JP5999516B2 - Radiography equipment - Google Patents

Description

  The present invention relates to a radiation imaging apparatus that performs tomography by acquiring tomographic images based on a plurality of projection images.

  An X-ray inspection apparatus will be described as an example of the radiation imaging apparatus. Conventionally, as shown in FIG. 7, this type of X-ray inspection apparatus includes a stage S on which an object O is placed and an X-ray tube T ( Radiation irradiating means) and an X-ray detector D (radiation detecting means). The stage S is a rotation stage having a rotation mechanism, and rotationally drives the rotation stage around the axis of the rotation axis Ax.

  Note that X-ray inspection objects include mounting substrates, through-holes / patterns / solder joints of multilayer substrates, electronic components before mounting such as integrated circuits (ICs) placed on pallets, metal There are castings such as video decks.

  In particular, when performing X-ray inspection by tomography of an object having a very fine structure such as a Ball Grid Array (BGA) or wiring, it is necessary to perform imaging with a large enlargement ratio. However, in order to increase the enlargement ratio, it is necessary to photograph a radiation source typified by an X-ray tube close to the object. Therefore, if the object has a wide shape on a plane, the X-ray tube and the object May interfere with each other. As a result, the enlargement rate cannot be increased so much to avoid interference.

  Therefore, as shown in FIG. 8, the rotation stage S and the X-ray tube T and the X-ray detector D are arranged in an axial direction inclined by a certain angle (lamino angle) with respect to the rotation axis Ax for rotationally driving the rotation stage S. It arrange | positions (for example, refer patent document 1). In the case of FIG. 8, the X-ray tube T is fixedly arranged, and the rotary stage S is rotationally driven around the axis of the rotary axis Ax. At the time of data acquisition, the X-ray detector D detects X-rays irradiated from the X-ray tube T and transmitted through the object O from an oblique direction inclined by the lamino angle, and on the detection surface of the X-ray detector D based on the detection. A projected image is obtained. A projection image is acquired from a plurality of angles by acquiring a projection image each time the rotary stage S is rotationally driven.

  Thus, by arranging the X-ray tube and the X-ray detector in the oblique direction inclined by the lamino angle and photographing from the oblique direction, it is possible to bring the X-ray tube and the rotation stage and consequently the object close to each other. There is an advantage that a projection image with a high magnification can be obtained without interference between the ray tube and the object. However, since there is a restriction on the degree of freedom of the drive system, it is difficult to obtain a projected image of an object from an arbitrary position, and there is a drawback that the application is limited to CT (Computed Tomography).

  Therefore, for example, as shown in FIG. 9, there is known a method for realizing photographing from an oblique direction with an apparatus that does not have a special rotation mechanism in the stage S (see, for example, Patent Documents 2 and 3). In FIG. 9, the stage S together with the object O is translated (moves straight) along a plane perpendicular to the rotation axis Ax (horizontal plane in FIG. 9) so as to draw a circular orbit, and the same rotation is synchronized with the movement of the stage S. By rotating the X-ray detector D around the axis of the axis Ax, a plurality of projection images are acquired, and further, a tomographic image is acquired based on the plurality of projection images.

  As described above, the relative geometric relationship between the X-ray tube, the object, and the X-ray detector at the time of imaging in FIG. 9 is the same as in FIG. 8 (the object and the rotary stage are driven to rotate around the axis of the rotation axis Ax. In this case, the images are taken in an oblique direction by synchronously driving them so as to be the same as in FIG. In the case of FIG. 9, unlike FIG. 8, the direction of the stage S can be fixed. Further, there are many apparatus configurations other than those shown in FIG. 9 for realizing imaging from an oblique direction. For example, there is a method of driving an X-ray tube and an X-ray detector by fixing a stage (and an object). (For example, refer to Patent Document 4).

JP 2005-106515 A JP 2010-2221 A JP 2006-162335 A Patent No. 4490943

  However, as shown in FIG. 9, when CT imaging is performed from an oblique direction, the degree of freedom of the drive system is greater than that of the CT-dedicated apparatus having only one degree of freedom of stage rotation, and the drive accuracy of each drive system is increased. Is important. In particular, since the stage and the X-ray detector are independent drive mechanisms, a highly accurate positioning and synchronization mechanism and control are required to obtain an ideal tomographic scanning trajectory. There is a problem that it becomes expensive.

  Specifically, as the X-ray tube and the stage are brought closer to each other and imaged at a higher magnification, the influence of the stage driving accuracy on the projection image becomes larger. For this reason, when CT imaging is performed from an oblique direction at a high magnification, the stage needs to operate so as to draw a circular orbit with high accuracy. In order to realize high-precision driving of such a stage, it is necessary that the mechanism is highly rigid and that minute position control (positioning) is possible, which increases costs. .

Further, in order to operate the stage so as to draw a circular orbit, as shown in FIG. 10, two orthogonal drive systems (X-axis and Y-axis of the orthogonal coordinate system) are driven by a sine wave (90 ° out of phase). Each position may be controlled so that a sine wave is obtained. _{P X} in FIG. 10 is an X-coordinate value, _{P Y} is a Y coordinate value. However, when sampling at regular intervals with a certain rotation angle at the time of shooting, the driving amount is a position where the gain of the sine wave is large (the angles θ in the Y coordinate in FIG. 10 are around 0 °, 180 °, 360 °, and in the X coordinate. When the angle θ is around 90 ° and 270 °, the driving amount of each axis becomes small and the driving direction needs to be reversed. As described above, since the minute driving is performed at the position where the driving direction is reversed, there is a problem that the influence of static friction and backlash is increased, and it is difficult to ensure the driving accuracy.

  These problems are not limited to the case where CT imaging is performed from an oblique direction by driving the stage and the X-ray detector. For example, even when CT imaging is performed from an oblique direction by driving an X-ray tube and an X-ray detector, in order to achieve an oblique CT function at a high magnification rate, the X-ray tube has a circular orbit with high accuracy. Has the same problem that needs to be drawn.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a radiation imaging apparatus that can maintain driving accuracy at low cost.

In order to achieve such an object, the present invention has the following configuration.
That is, the radiation imaging apparatus of the present invention is irradiated with a stage on which an object is placed, radiation irradiation means and radiation detection means arranged to face each other with the stage interposed therebetween, and the radiation irradiation means. A radiation imaging apparatus comprising: a calculation unit that calculates a tomographic image based on a plurality of projection images obtained by detecting radiation transmitted through the object by the radiation detection unit; At least one of the radiation irradiating means and the stage so that the combined trajectory of the driven parts driven by the respective rectilinear drive mechanisms becomes a trajectory according to a circular trajectory. comprising a combined drive unit for driving the driving unit, and control means for controlling the combined drive means, said control means, each of the straight drive at the inverting area The absolute value of the moving amount per unit step of the mechanism, based on the condition that is set to a predetermined value or more or "0" having a positive value larger than the movement amount in the inversion region when the circular orbit, each The linear drive mechanism is controlled to achieve a trajectory according to the circular trajectory, and from a small circular orbit having a half size of the circular orbit to a concentric circle of the circular orbit. The combined driving means is controlled by setting a trajectory in a range up to a great circular trajectory as a trajectory according to the circular trajectory.
Here, the above-described tomographic image in the present invention is a three-dimensional tomographic image including a plurality of tomographic images, and of course includes a case of a single tomographic image.

If two or more linear drive mechanisms are used to achieve a circular orbit, the drive is always fine at a position where the drive direction of the linear drive mechanism is reversed, so that the effect of static friction and backlash increases and the drive accuracy is maintained. I can't. Therefore, according to the radiographic apparatus according to the present invention, the control means sets the absolute value of the amount of movement per unit step of each rectilinear drive mechanism in the inversion region to be larger than the amount of movement in the inversion region in the case of a circular orbit. Under the condition that the positive value is equal to or greater than a predetermined value or “0”, each linear drive mechanism is controlled to realize a track corresponding to a circular track. By this control, the amount of movement equal to or greater than the predetermined value or the amount of movement of “0” (that is, the stopped state) is obtained without performing minute driving at a position where the driving direction of the linear drive mechanism is reversed. Further, the control means removes the restriction of the circular orbit and, from the small circular orbit having a half size of the concentric circle of the circular orbit, under the restriction that the minute driving is not performed at the position where the driving direction of the linear drive mechanism is reversed. The trajectory in the range up to a large circular orbit that is a concentric circle twice the size of the circular orbit is used as a trajectory according to the circular orbit, and at least one of the radiation irradiating means and the stage is driven and controlled. . At this time, the control means is a combination of two or more rectilinear drive mechanisms so that the combined trajectory of the driven parts driven by the respective rectilinear drive mechanisms becomes a trajectory according to the circular trajectory (described above). The composite driving means is controlled. As a result, it is possible to maintain the drive accuracy without performing a minute drive at a position where the drive direction of the linear drive mechanism is reversed. In addition, the movement amount per unit step of one of the two linear drive mechanisms is set to “0” (that is, the stopped state), and the linear drive is operated only by the other linear drive mechanism. By adopting the trajectory that incorporates the movement, the position control in each of the rectilinear drive mechanisms (drive systems) can be simplified, and the driving accuracy can be easily maintained. Moreover, since the mechanically required rigidity condition is eased by improving the driving accuracy, the cost can be reduced, and low cost can be realized in each linear drive mechanism (drive system).

An invention (the latter invention) different from the above-described invention (the former invention) is a stage on which an object is placed, a radiation irradiating means and a radiation detection arranged so as to face each other with the stage interposed therebetween And a computing means for computing a tomographic image based on a plurality of projection images obtained by detecting radiation emitted from the radiation irradiating means and transmitted through the object by the radiation detecting means. A radiation imaging apparatus comprising: a combination of two or more linear drive mechanisms, wherein the radiation irradiation is performed so that a combined trajectory of a driven part driven by each of the linear drive mechanisms becomes a trajectory according to a circular trajectory. And a composite drive means for driving at least one of the stages as the driven portion, and a control means for controlling the composite drive means, wherein the control means comprises a unit step. Under the condition that the absolute value of the amount of movement per hit is equal to or greater than a predetermined value having a positive value or “0”, each linear drive mechanism is controlled to realize a trajectory according to the circular trajectory. And a trajectory in a range from a small circular orbit having a half size in a concentric circle of the circular orbit to a large circular orbit having a size twice as large as a concentric circle in the circular orbit as a trajectory according to the circular orbit, The combination driving means is controlled.
Further, the above-described combined drive means is composed of two orthogonal drive mechanisms that are orthogonal to each other, and while the amount of movement per unit step is not less than a predetermined value (having a positive value), the track of the driven part is a circular track. In addition to controlling the composite drive means so as to become itself, only the region where the drive direction of one of the straight drive mechanisms is reversed, the movement amount per unit step of one of the straight drive mechanisms is set to “0”, Only in the region where the drive direction of the other straight drive mechanism is reversed, the movement amount per unit step of the other straight drive mechanism is set to “0”, so that the track of the driven part is a track corresponding to a circular track. In other words, each of the linear drive mechanisms is controlled. That is, only in the region where the drive direction of one of the two linear drive mechanisms is reversed, the movement amount per unit step of one of the linear drive mechanisms is set to “0”, and the other regions (In other words, while the amount of movement per unit step is greater than or equal to a predetermined value having a positive value) By setting the same trajectory as the circular trajectory, the influence of the false image that occurs when moving out of the circular trajectory is minimized. In addition, it is possible to improve the driving accuracy in a problematic area (an area where the driving direction of the linear drive mechanism is reversed). The predetermined value in the former invention has a positive value larger than the amount of movement in the reversal region in the case of a circular orbit, whereas the predetermined value in the latter invention is simply a positive value. Please keep in mind.
In one example of the above-described invention (the former invention) , the above-mentioned combined drive means is composed of two orthogonal drive mechanisms that are orthogonal to each other, and the control means has a circular orbit while the track of the driven part is outside the reversal region. The combined drive means is controlled so that it becomes the same, and only the region where the drive direction of one of the rectilinear drive mechanisms is reversed is the amount of movement per unit step of one of the rectilinear drive mechanisms (movement in the reversal region when a circular orbit is used) Set a fixed value equal to or greater than a predetermined value (having a positive value greater than the amount ), and similarly, move the unit of the other linear drive mechanism per unit step only in the region where the drive direction of the other linear drive mechanism is reversed. By setting the absolute value of the quantity to a fixed value (described above), each of the linear drive mechanisms is controlled so that the trajectory of the driven part becomes a trajectory according to the circular trajectory. In other words, only in the region where the drive direction of one of the two linear drive mechanisms is reversed, the movement amount per unit step of one of the linear drive mechanisms, or the absolute value of the movement amount, is calculated based on the circular orbit. By setting a fixed value equal to or greater than a predetermined value having a positive value larger than the amount of movement in the reversal area at the time , as shown in FIG. In the region, the circular vertex that protrudes from the circular orbit is assumed to be an extra orbit, minimizing the influence of the false image that is generated when it deviates from the circular orbit, and driving accuracy in the problematic region (the region where the drive direction of the linear drive mechanism is reversed) Can be improved.

In another example of the above-described invention (the former invention) , the above-described combined drive means is composed of two orthogonal drive mechanisms that are orthogonal to each other, and the trajectory according to the circular trajectory is from the small circular trajectory to the great circular trajectory. The control means, when driving corresponding to one side of the quadrangular trajectory, has a movement amount per unit step (having a positive value) when driving corresponding to one side of the quadrangular trajectory. ) A rectangular trajectory is realized by setting a fixed value equal to or greater than a predetermined value and driving, and setting the amount of movement per unit step by the other straight drive mechanism to “0”. When driving corresponding to one side of the square track, the other linear drive mechanism is set to a movement amount of “0” (that is, stopped), and the movement amount per unit step by one linear drive mechanism is set to By implementing the rectangular trajectory by setting a fixed value equal to or greater than a predetermined value, the position control can be simplified and the driving accuracy is improved. In addition, since it is a straight traveling track, it can be driven in a shorter time than a circular track, and the data collection time related to imaging can be shortened.
Still another example of the above-described invention (the former invention) is that the above-described combined drive means is composed of two orthogonal drive mechanisms that are orthogonal to each other, and the trajectory according to the circular orbit is from the small circle orbit to the great circle. The trajectory is a trajectory up to the trajectory and is a quadrangular trajectory. When the control means performs driving corresponding to one side of the quadrangular trajectory, the absolute value of the amount of movement per unit step by one of the linear drive mechanisms is corrected (corrected). And driving by setting a fixed value equal to or greater than a predetermined value) and driving the absolute value of the amount of movement per unit step by the other straight drive mechanism to a fixed value (described above), It is to realize a square orbit. When driving corresponding to one side of the rectangular orbit, by setting the absolute value of the amount of movement per unit step by each linear drive mechanism to a fixed value (having a positive value) above a predetermined value, As shown in FIG. 5 (a), a rectangular orbit having a vertex in the drive axis direction of the linear drive mechanism is used, so that the position control is simplified and the drive accuracy is improved. In addition, since it is a straight traveling track, it can be driven in a shorter time than a circular track, and the data collection time related to imaging can be shortened.

In these inventions described above, it is preferable to include a detection drive means for driving the radiation detection means in synchronization with the drive of the driven part by the composite drive means. By operating the radiation detection means, it is possible to secure a field of view and to calculate a tomographic image of a wider area.

  In the case where the detection driving means is provided, the detection driving means detects the radiation detection means so that the radiation emitted from the radiation irradiation means passes through the target point of the object and is detected at the center of the radiation detection means. More preferably, it is driven. By capturing the point of interest at the center of the radiation detection means, it is possible to reconstruct (back projection) at almost the same position (point of interest) when calculating a tomographic image, which is sufficient based on the center of the field of view. A wide range of tomographic images can be obtained.

According to the radiation imaging apparatus according to the present invention (the former and the latter inventions) , the control means removes the restriction of the circular orbit, and under the restriction that the micro drive is not performed at the position where the drive direction of the rectilinear drive mechanism is reversed, Radiation irradiation with a trajectory in the range from a small circular orbit that is half the size of a concentric circle of the circular orbit to a large circular orbit that is twice the size of a concentric circle of the circular orbit and that conforms to the circular orbit At least one of the means and the stage is driven and controlled as a driven part to control the composite driving means composed of a combination of two or more linear drive mechanisms. As a result, driving accuracy can be maintained at low cost.

It is a schematic block diagram of the X-ray inspection apparatus which concerns on an Example. It is a block diagram of the X-ray inspection apparatus which concerns on an Example. (A) is a circular orbit, a concentric circle of a circular orbit having a half size, a concentric circle of a circular orbit having a double size and a circular orbit inscribed in a circular orbit. FIG. 5B is a schematic diagram illustrating a regular triangle circumscribing a circle and a regular triangle inscribed in a great circle orbit and circumscribed in a circle orbit, and FIG. A regular triangle that divides a regular hexagon by connecting the diagonal of the regular hexagon and passing through the center of the circular or great circular orbit, a side that connects the diagonal of the regular hexagon and does not pass through the center of the circular or great circular orbit, and the corresponding side -It is the schematic which also illustrated the right triangle formed with the edge | side of a regular triangle and the edge | side which passes along the center of a great circle orbit. (A) is a normal circular orbit for comparison of (b) and (c) and an X coordinate value and a Y coordinate value when realizing a circular orbit, and (b) is a trajectory obtained by shortcutting a circular orbit and its An X coordinate value and a Y coordinate value when realizing the trajectory, and (c) are a quadrature trajectory and an X coordinate value and a Y coordinate value when realizing the trajectory. (A)-(d) is each form of the track | orbit according to the circular track | orbit concerning a modification. (A)-(e) is each drive form for implementing the diagonal imaging | photography concerning a modification. It is the schematic of the conventional imaging | photography. It is the schematic of the conventional diagonal imaging | photography. It is the schematic of the conventional diagonal imaging | photography when a stage is moved in parallel and an X-ray detector is rotationally driven synchronizing with the movement of a stage. These are the X coordinate value and the Y coordinate value when realizing a normal circular orbit.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an X-ray inspection apparatus according to the embodiment, and FIG. 2 is a block diagram of the X-ray inspection apparatus according to the embodiment. In the present embodiment, an X-ray inspection apparatus will be described as an example of a radiation imaging apparatus.

As shown in FIG. 1, an X-ray inspection apparatus 1 includes a stage 2 on which an object O is placed, and an X-ray tube 3 and an X-ray detector arranged so as to face each other with the stage 2 interposed therebetween. 4 is provided. The X-ray detector 4 is not particularly limited, as exemplified by an image intensifier (II), a flat panel X-ray detector (FPD: Flat Panel Detector), and the like. In the present embodiment, a flat panel X-ray detector (FPD) will be described as an example of the X-ray detector 4. The stage 2 corresponds to the stage in the present invention, the X-ray tube 3 corresponds to the radiation irradiation means in the present invention, and the X-ray detector 4 corresponds to the radiation detection means in the present invention. The stage 2 also corresponds to the driven part in the present invention.

  The FPD is composed of a plurality of detection elements arranged vertically and horizontally corresponding to pixels, and the detection elements detect X-rays and output detected X-ray data (charge signals) as X-ray detection signals. In this way, the X-rays irradiated from the X-ray tube 3 and transmitted through the object O are detected by the X-ray detector 4 made of FPD and output an X-ray detection signal, and the pixel value based on the X-ray detection signal Are arranged in correspondence with the pixels to obtain a projection image projected on the detection surface of the X-ray detector 4.

Other, X-ray inspection apparatus 1, as shown in FIG. 1, tilting the detector rotation mechanism 5 for rotating the X-ray detector 4 around arrow R _1, the X-ray detector 4 in the arrow R ₂ direction And a detector tilting mechanism 6 to be operated. The detector tilting mechanism 6 includes an arcuate guide portion 6a that supports the X-ray detector 4, and a rotary motor 6b (see FIG. 2). The rotary motor 6b is driven to rotate, and thus the detector tilt mechanism 6 extends along the guide portion 6a. X-ray detector 4 is tilted in the arrow R ₂ direction of Te. The detector rotation mechanism 5 corresponds to the detection drive means in this invention.

Detector rotation mechanism 5 is composed of a rotary motor 5a (see FIG. 2), by rotating the motor 5a rotationally drives the guide portion 6a of the detector tilt mechanism 6 around the arrow R _1, is supported by the guide portion 6a X-ray detector 4 is also rotated about arrow R _1. In this embodiment, the detector rotation mechanism 5 rotates the X-ray detector 4 around the arrow R ₁ in synchronization with the drive of the stage 2. In particular, the detector rotation mechanism 5 moves the X-ray detector 4 to the arrow so that X-rays emitted from the X-ray tube 3 pass through the target point of the object O and are detected at the center of the radiation detector 4. for rotating about the R _1.

  In addition, as shown in FIG. 2, the X-ray inspection apparatus 1 includes a stage drive mechanism 7 that drives the stage 2 straightly in an orthogonal coordinate system X, Y, and Z (see FIG. 1), and a plurality of projection images. A tomographic image calculation unit 8 that calculates and calculates a tomographic image based thereon, a controller 9 that performs overall control thereof, and outputs a tomographic image obtained by the tomographic image calculation unit 8 (display output on a monitor or print output on a printer) And an image output unit 10 for performing the operation. The stage drive mechanism 7 includes an X-axis linear motor 7a that linearly drives the stage 2 in the X direction (here, horizontal drive), a Y-axis linear motor 7b that linearly drives the stage 2 in the Y direction (here, horizontal drive), and a stage. 2 is composed of a Z-axis rectilinear motor 7c that linearly drives in the Z direction (in this case, lift drive). In the present embodiment, the stage 2 is driven by a trajectory in which the synthesis of the trajectories by the X-axis rectilinear motor 7a and the Y-axis rectilinear motor 7b is based on a circular trajectory. The trajectory according to the circular trajectory will be described later in detail. The stage drive mechanism 7 corresponds to the composite drive means in the present invention, and the X-axis linear motor 7a, the Y-axis linear motor 7b, and the Z-axis linear motor 7c correspond to the linear drive mechanism in the present invention, and the tomographic image calculation unit 8 Corresponds to the calculation means in the present invention, and the controller 9 corresponds to the control means in the present invention.

  The tomographic image calculation unit 8 calculates and calculates a tomographic image based on a plurality of projection images. The controller 9 comprehensively controls each part constituting the X-ray inspection apparatus 1, and in particular, a rotation motor 5 a of the detector rotation mechanism 5, a rotation motor 6 b of the detector tilting mechanism 6, and an X-axis linear motor of the stage drive mechanism 7. 7a, Y-axis rectilinear motor 7b and Z-axis rectilinear motor 7c are respectively controlled. Although the X-ray tube 3 is in the fixed position in FIG. 1, the controller 9 may control the X-ray tube 3 to be tiltable according to the tilting of the X-ray detector 4. Specific control by the controller 9 will also be described in detail later. The tomographic image calculation unit 8 and the controller 9 described above are configured by a central processing unit (CPU) and the like.

  As shown in FIG. 1, by arranging the X-ray tube 3, the object O, and the X-ray detector 4, the X-ray tube 3 and the X-ray detector 4 in an oblique direction inclined by the lamino angle, as in FIG. 9. And can be taken from an oblique direction. Then, the X-ray tube 3 and the stage 2 and thus the object O can be brought close to each other, and a high-magnification projection image can be obtained without the X-ray tube 3 and the object O interfering with each other. A tomographic image calculation unit 8 shown in FIG. 2 acquires a projection image from a plurality of angles by acquiring a projection image each time the stage 2 is driven in a trajectory according to a circular orbit, and the tomographic image calculation unit 8 shown in FIG. Compute and calculate a tomographic image.

  Here, the range of the orbit according to the circular orbit will be described with reference to FIG. FIG. 3A shows a circular orbit, a concentric circle of a circular orbit having a half size, a circular orbit of a concentric circle having a size twice as large, a circular orbit inscribed in a small circle. FIG. 3B is a schematic diagram illustrating an equilateral triangle circumscribing the circular orbit and an equilateral triangle inscribed in the great circle orbit and circumscribing the circular orbit; FIG. Regular hexagons inscribed in the trajectory, connecting the diagonals of the regular hexagons, equilateral triangles that divide the regular hexagons along the sides passing through the centers of the circular or great circular orbits, and connecting the diagonals of the regular hexagons to the centers of the circular or great circular orbits It is the schematic which also illustrated the right-angled triangle formed in the edge | side which does not pass and the edge | side which passes along the said edge | side, the edge | side of an equilateral triangle, and the center of a great circle orbit.

  There is no limit to the orbit according to the circular orbit. In this specification, a circular orbit that is half the size of the concentric circle of the standard circular orbit is called a “small circular orbit”, and doubled by the concentric circle of the standard circular orbit. If each circular orbit having a size is defined as a “large circle orbit”, the trajectory in the range from the small circle orbit to the great circle orbit is defined as a trajectory according to the circular orbit. Therefore, a trajectory that does not draw inside the small circular orbit and does not draw outside the great circular orbit is a trajectory according to the circular orbit. Here, the small circular orbit is a concentric circle of the (standard) circular orbit and half the size, and the large circular orbit is a circular orbit that is twice the size of the (standard) concentric circle. The reason is as follows.

Considering a regular polygon inscribed in a (standard) circular orbit, the circle inscribed in the regular polygon is the smallest. The regular polygon is a regular triangle, and the circle inscribed in the regular triangle. It is. Conversely, when considering a regular polygon circumscribing a (standard) circular orbit, the circle that circumscribes the regular polygon is the largest when the regular polygon is an equilateral triangle. A circumscribed circle. As shown in FIG. 3 (a), a circular orbit as a standard and C, (the standard) and equilateral triangle inscribed in the circular orbit C and TR _1, the circular path inscribed in the regular triangle TR ₁ C _S Let TR ₂ be a regular triangle circumscribing the (standard) circular orbit C, and let C _B be a circular orbit circumscribing the regular triangle TR ₂ .

(The standard) diameter of the circular orbit C, and focused only the relationship between the diameter of the circular orbit C _B circumscribing an equilateral triangle TR _2. As shown in FIG. 3 (b), the regular hexagon inscribed in circular orbit C _B and HEX, obtained by dividing the regular hexagon HEX at the sides passing through the center of the circular orbit C · C _B bear diagonal regular hexagon HEX positive When the triangle is TR ₃ , the regular hexagon HEX is divided into six regular triangles TR ₃ . On the other hand, as shown in FIG. 3 (b), the side that does not pass through the center of the circular orbit _{C-C B} bear diagonal regular hexagon HEX and AB, edge-circular orbit C of the sides AB, equilateral triangle TR ₃ A right triangle formed by a side passing through the center of _B is referred to as TR ₄ (see the thick frame in FIG. 3B).

Right triangle TR ₄ becomes a triangle bisected by a line with a perpendicular line is drawn from the apexes of an equilateral triangle TR ₃ (a portion of the side AB), the length of the hypotenuse of a right triangle TR ₄ are circular orbit C _B radial Thus, the length of the side perpendicular to the perpendicular is the radius of the circular trajectory C (which is standard). The length of the hypotenuse of a right triangle TR _4: the length of the side perpendicular to the vertical line is 2: 1 relationship. Therefore, as shown in FIG. 3B, when the radius of the circular trajectory C (standard) is r, the length of the side perpendicular to the perpendicular is equal to the radius r of the circular trajectory C, and the right triangle TR ₄ the length of the hypotenuse is 2r, and consequently, the radius of the circular orbit C _B is equal to the length 2r of the hypotenuse of a right triangle TR _4.

That is, radius 2r of the circular orbit _{C B} circumscribing an equilateral triangle TR ₂ in FIG. 3 (a), is twice that (a standard) radius r of the circular orbit C, the circular orbit _{C B} is the circular orbit C It is a great circle orbit having a double size. Therefore, the circular path having a large circular orbit the C _B (the standard) twice as large as in the concentric circular orbit C. For the same reason, (a standard) a circular orbit C (inscribed in equilateral triangle TR ₁ in FIG. 3 (a)) replaced by the circular orbit _{C S,} (the standard) a large circular orbit _{C B} circular orbit C when replaced, the circular orbit C is a circular path having twice the size in concentric circular orbit C _S. In other words, the circular orbit C _S becomes a small circular path having half the size in the concentric circular orbit C.

  Next, an example of a specific orbit according to a circular orbit will be described with reference to FIG. FIG. 4 (a) is a normal circular orbit for comparison with FIG. 4 (b) and FIG. 4 (c), and the X coordinate value and the Y coordinate value when realizing the circular orbit. FIG. Is a trajectory obtained by shortcutting a circular trajectory and an X coordinate value / Y coordinate value when the trajectory is realized, and FIG. 4C is an X coordinate value / Y coordinate value when realizing a quadrangular trajectory and the trajectory. It is. 4 (a) to 4 (c), the horizontal axis represents θ in FIGS. 4 (a) to 4 (c), and the starting point (θ) indicated by the black circles in FIGS. 4 (a) to 4 (c). = 0 °) to the end point (θ = 360 °) indicated by the arrow in FIGS. 4 (a) to 4 (c), and the vertical axes in FIGS. 4 (a) to 4 (c) are , X coordinate value / Y coordinate value. Further, the X coordinate value / Y coordinate value when realizing the circular orbit of FIG. 4A is the same as the X coordinate value / Y coordinate value shown in FIG.

As shown in FIG. 4 (a), the conventional ordinary circular orbit has a sine wave (sin wave) because the X coordinate value P _X and the Y coordinate value P _Y draw a circular orbit as described in FIG. ) Therefore, the driving amount (absolute value of the movement amount per unit step) is a region where the gain of the sine wave is large (the angle θ at the Y coordinate in FIG. 4A is around 0 °, 180 °, 360 °, X The angle θ in the coordinates becomes smaller at around 90 ° and 270 °, respectively, and the driving directions of the X-axis linear motor 7a and the Y-axis linear motor 7b (see FIG. 1) are reversed. Therefore, when the stage 2 is linearly driven by the X-axis linear motor 7a and the Y-axis linear motor 7b, the composition of the trajectory by the X-axis linear motor 7a and the Y-axis linear motor 7b is the circular orbit shown in FIG. In this case, the effect of the above-mentioned static friction and backlash becomes large, and it becomes difficult to ensure driving accuracy.

  Therefore, as shown in FIG. 4 other than FIG. 4A, the restriction of the circular orbit is removed, and a linear orbit (straight drive) is adopted in at least a part of the orbit. There are many examples of trajectories that can eliminate the minute driving at the position where the driving direction seen in the circular trajectory is reversed, and these trajectories are referred to as “circular orbits”. It should be noted that if the image is too deviated from the standard circular orbit (for example, an ellipse having a long axis exceeding 4 times the short axis), a plurality of projection images obtained when the image is too deviated If a tomographic image is calculated and calculated based on this, a correct value cannot be obtained for a tomographic image reconstructed with a standard circular orbit. This can also be seen from the fact that the tomographic images of CT and oblique CT are different, considering an extreme example.

Therefore, as described above, the trajectory according to the circular trajectory is not limited, and a small circular trajectory C _S (FIG. 3 (a)) that is a concentric half of the circular trajectory C (see FIG. 3 (a)) is half. The trajectory in a range from a reference circle) to a great circle orbit C _B (see FIG. 3A) that is a concentric circle of the circle orbit C and has a size twice as large as that of the circle orbit C is a trajectory according to the circular orbit. Further, when a tomographic image is calculated and calculated based on a plurality of projection images obtained in each trajectory shown in FIG. 4 other than FIG. 4A, it is almost the same as a tomographic image reconstructed with a standard circular trajectory. It has been confirmed that this will result.

For example, as shown in FIG. 4B, when the X coordinate value P _X and the Y coordinate value P _Y draw a trajectory that is a shortcut of the circular trajectory, it is larger than the minute driving amount at the position where the driving direction is reversed. , a predetermined value having a positive value. Then, the drive amount (absolute value of the movement amount per unit step) is set to be equal to or greater than the predetermined value or “0”, and the controller 9 (see FIG. 2) sets the X-axis linear motor 7a and the Y-axis linear motor 7b. To control each.

More specifically, each of the X-axis linear motor 7a and the Y-axis linear motor 7b that are linearly driven in the Cartesian coordinate system maintains a predetermined value or more with a driving amount such that the synthesis of the trajectory becomes the circular trajectory. The X-axis linear motor 7a and Y-axis linear motor 7b are respectively controlled, and the drive amount is set to “0” only in the region where the driving directions of the X-axis linear motor 7a and Y-axis linear motor 7b are reversed. Then , the composite drive means (the stage drive mechanism 7 in this embodiment) composed of a combination of the X-axis linear motor 7a and the Y-axis linear motor 7b is controlled. That is, only the region where the driving direction of each of the X-axis linear motor 7a and Y-axis linear motor 7b is reversed, the driving amount is set to “0” (a circular track is shortcut) and other regions (ie, , the moving amount per unit steps is the same track as the is between) the said circular path than the predetermined value having a positive value. Accordingly, as shown on the right side of the drawing, only the region where the driving direction is reversed is “0”, and the sine wave is generated in other regions. As described above, only in the region where the driving direction is reversed, the driving amount is set to “0” as a straight traveling trajectory, and in the other regions, the same trajectory as the circular trajectory is generated. Can be reduced as much as possible, and the drive accuracy in the problematic region (region where the drive directions of the X-axis linear motor 7a and Y-axis linear motor 7b are reversed) can be improved.

For example, as shown in FIG. 4C, the same applies when the X coordinate value P _X and the Y coordinate value P _Y draw a quadrangular trajectory (a square trajectory inscribed in the circular trajectory in FIG. 4C). Is set to a predetermined value having a positive value. Then, the driving amount (absolute value of the moving amount per unit step) is set to the predetermined value or more or “0”, and the controller 9 is a composite composed of a combination of the X-axis linear motor 7a and the Y-axis linear motor 7b. The driving means (the stage driving mechanism 7 in this embodiment) is controlled.

More specifically, this quadrangular trajectory is a trajectory in the range from the small circular trajectory C _S to the great circular trajectory C _{B. When} the controller 9 performs driving corresponding to one side of the quadrangular trajectory, Linear drive mechanism (if one linear drive mechanism is an X-axis linear motor 7a , the other linear drive mechanism is a Y-axis linear motor 7b , and if one linear drive mechanism is a Y-axis linear motor 7b , the other linear drive with mechanism drives the moving amount per unit step by X-axis linear motor 7a) (having a positive value) is set to a predetermined value or more fixed values, the mobile unit stearyl Tsu per flop by the other linear drive mechanism The rectangular trajectory is realized by setting the quantity to “0”. For example, as shown in the right of the drawing, when controlling only the X-axis linear motor 7a X coordinate value P _X is varied in response to one of the sides of the rectangle trajectory (straight in the X direction), Y The drive amount in the shaft linear motor 7b is set to “0”, the Y coordinate value _PY is fixed, and the motor is stopped. Conversely, Y coordinate values P _Y by controlling only the Y-axis linear motor 7b is (straight in the Y direction) varies in response to one of the sides of the rectangle orbit case, the driving of the X-axis linear motor 7a the amount of "0" to the X-coordinate value P _X to the fixed set to the stopped state. Thus, the movement amount of “0” (that is, the stop state) is set, and the movement amount per unit step by one of the linear drive mechanisms (motors) is set to a fixed value (having a positive value ) that is a predetermined value or more. Thus, by realizing the rectangular trajectory, the position control is simplified, and the driving accuracy is improved. In addition, since it is a straight traveling track, it can be driven in a shorter time than a circular track, and the data collection time related to imaging can be shortened.

As described above, when the circular orbit shown in FIG. 4A is realized by two or more rectilinear drive mechanisms (X-axis rectilinear motor 7a and Y-axis rectilinear motor 7b in this embodiment), the rectilinear drive mechanism Since the driving is always performed at a position where the driving direction is reversed, the influence of static friction and backlash increases and the driving accuracy cannot be maintained. Therefore, according to the X-ray inspection apparatus according to the present embodiment having the above-described configuration, the controller 9 sets the absolute value (drive amount) of the movement amount per unit step to a predetermined value having a positive value or more or “ Under the condition of “0”, each linear drive mechanism (X-axis linear motor 7a, Y-axis linear motor 7b) is controlled to realize a track in accordance with the circular track . By this control, the amount of movement equal to or greater than the predetermined value or the amount of movement of “0” (that is, the amount of movement of “0”) (ie, the amount of movement equal to or greater than the predetermined value) is not driven at a position where the driving direction of the linear drive mechanism (X-axis linear motor 7a, Y-axis linear motor 7b) is reversed. Stop state).

In addition, the controller 9 removes the restriction of the circular orbit and, under the restriction that the minute drive is not performed at a position where the drive direction of the rectilinear drive mechanism (X-axis rectilinear motor 7a, Y-axis rectilinear motor 7b) is reversed, The stage 2 is driven with a trajectory ranging from a small circular orbit that is half the size of a concentric circle to a large circular orbit that is twice the size of a concentric circle of the circular orbit. Drive and control as a unit . At this time, as a trajectory combined trajectory of the driven unit that is driven by a respective linear drive mechanisms pursuant to (above) the circular orbit, controller 9, two or more linear drive mechanisms ( X-axis linear motors 7a, controls the combined drive means consisting of Y-axis linear combination of the motor 7b) (stage drive mechanism 7). As a result, the driving accuracy can be maintained without performing minute driving at a position where the driving direction of the rectilinear drive mechanism (X-axis rectilinear motor 7a, Y-axis rectilinear motor 7b) is reversed.

In addition, the movement amount per unit step of one of the two linear drive mechanisms (X-axis linear motor 7a, Y-axis linear motor 7b ) is set to “0” ( that is, stopped state), and the other By adopting a trajectory that adopts the movement of driving straightly by operating only the straight drive mechanism, the position control in each straight drive mechanism (drive system) can be simplified, and the drive accuracy can be easily maintained. There is. Moreover, since the mechanically required rigidity condition is eased by improving the driving accuracy, the cost can be reduced, and low cost can be realized in each linear drive mechanism (drive system).

  In this embodiment, preferably, a detector rotating mechanism 5 for driving the X-ray detector 4 in synchronization with the driving of the stage 2 is provided. By operating the X-ray detector 4 as well, an imaging field of view can be secured, and a tomographic image of a wider area can be calculated.

  When the detector rotation mechanism 5 is provided, preferably, the X-rays emitted from the X-ray tube 3 pass through the point of interest of the object O and are detected at the central portion of the X-ray detector 4. The detector rotating mechanism 5 drives the X-ray detector 4. By capturing the point of interest at the center of the X-ray detector 4, it is possible to reconstruct (back projection) at substantially the same position (point of interest) when calculating a tomographic image. A sufficiently wide range of tomographic images can be obtained.

  The present invention is not limited to the above-described embodiment, and can be modified as follows.

  (1) In the above-described embodiments, the X-ray inspection apparatus has been described as an example of the radiation imaging apparatus. However, if the apparatus performs radiography by acquiring tomographic images based on a plurality of projection images, radiation Is not limited to X-rays, and may be radiation other than X-rays (α rays, β rays, γ rays, etc.).

  (2) The object is not particularly limited. As described above, mounting boards, through holes / patterns / solder joints on multilayer boards, electronic parts before mounting such as integrated circuits (ICs) placed on pallets, castings of metals, moldings such as video decks What is necessary is just to perform radiography with respect to a target object, as exemplified by goods.

  (3) In the above-described embodiment, the trajectory according to the circular trajectory is the trajectory shown in FIG. 4B or 4C. However, the trajectory is composed of a combination of two or more linear drive mechanisms, and has unit steps. The absolute value (drive amount) of the amount of movement per hit,PositiveGreater than or equal to a predetermined value or “0”ConfigurationAnd each Straight aheadAs long as each of the driving mechanisms is controlled and the trajectory in the range from the aforementioned small circular trajectory to the above great circular trajectory is a trajectory according to the circular trajectory, the present invention is not limited thereto. For example, as shown in FIG. 5 (a), it may be a rectangular orbit having a vertex in the direction of the drive axis (in this case, the X-axis and Y-axis), or as shown in FIG. In other areas, a circular vertex that is a circular orbit may be a protruding orbit. In addition, as shown in FIG. 5 (c), it may be a rectangular orbit that circumscribes the circular orbit (a square orbit in FIG. 5 (c)), or as shown in FIG. 5 (d), a circular orbit. It may be an equilateral triangular orbit that is inscribed or circumscribed.

  (4) In the above-described embodiment, the two X-axis linear motor 7a and Y-axis linear motor 7b shown in FIG. 2 are controlled to draw a trajectory according to a circular trajectory (along the horizontal plane). Draw a trajectory according to a circular trajectory along the vertical plane while keeping the horizontal posture, the object can be placed on the stage (for example, by a support member) even in the vertical posture, or a modification (8) described later If the radiation irradiation means (X-ray tube 3 in the embodiment) is driven as shown in FIG. 1, when the horizontal plane is the XY plane and the Z axis is the vertical axis as shown in FIG. The X-axis rectilinear motor 7a and the Z-axis rectilinear motor 7c (see FIG. 2) are controlled respectively, or the Y-axis rectilinear motor 7b and the Z-axis rectilinear motor 7c are respectively controlled so as to draw a trajectory according to the circular orbit Also good.

  (5) In the above-described embodiment, each linear drive mechanism (in the embodiment, two X-axis linear motors) is drawn so that a trajectory according to a circular trajectory is drawn, and a trajectory according to a circular trajectory along a horizontal plane is drawn. 7a and Y-axis rectilinear motors 7b) are controlled respectively, but each rectilinear drive mechanism is controlled so as to draw a trajectory according to a circular trajectory along the vertical plane as in the above-described modification (4). Alternatively, each straight drive mechanism may be controlled so as to draw a trajectory according to a circular trajectory along the slope.

  (6) In the above-described embodiment, combined drive means (stage drive in the embodiment) comprising a combination of the two X-axis rectilinear motors 7a and 7b shown in FIG. Although each of the mechanisms 7) is controlled, each of the combined drive means composed of a combination of three or more straight drive mechanisms may be controlled. To draw a trajectory according to the circular trajectory, for example, a Z-axis rectilinear motor 7c (see FIG. 2) may be combined in addition to the X-axis rectilinear motor 7a and the Y-axis rectilinear motor 7b. Further, the present invention is not limited to the orthogonal coordinate system. For example, at least one of the X-axis rectilinear motor 7a, the Y-axis rectilinear motor 7b, and the Z-axis rectilinear motor 7c, and an axis oblique to these axes. It may be combined with a motor that is driven in a straight line.

  (7) In the above-described embodiment, as shown in FIG. 1, the radiation irradiation means (X-ray tube 3 in the embodiment) and the radiation detection means (X-ray detector 4 in the embodiment) from the oblique direction inclined by the lamino angle. Were taken from an oblique direction, and as shown in FIGS. 6A to 6E, the radiation irradiation means (X-ray tube 3) and the radiation detection means (X-ray detector 4) were provided. You may arrange. Further, the radiation irradiation means may be arranged on the upper side and the radiation detection means may be arranged on the lower side.

(8) In the embodiment described above, the stage 2 is driven as shown in FIG. 1, but at least one of the radiation irradiation means (X-ray tube 3 in the embodiment) and the stage 2 is driven as a driven part. For example, the driven portion need not be only the stage 2 and is not limited to driving only the stage 2. The driven part may be radiation irradiation means (X-ray tube 3). For example, as shown in FIG. 6B or FIG. 6E, only the radiation irradiation means (X-ray tube 3) may be driven as a driven part, or as shown in FIG. You may drive both a radiation irradiation means (X-ray tube 3) and the stage 2 as a to- be-driven part .

  (9) In the above-described embodiment, as shown in FIG. 1, the radiation detection means (X-ray detector 4 in the embodiment) is driven in synchronization with the drive of the stage 2, but FIG. As shown in FIG. 6E, imaging may be performed without driving the radiation detection means (X-ray detector 4). In this case, there is an effect that no special drive mechanism is required for the radiation detection means (X-ray detector 4).

  (10) In the embodiment described above, as shown in FIG. 1, the radiation (X-ray in the embodiment) passes through the target point of the object O, and the center of the radiation detection means (X-ray detector 4 in the embodiment). Although the structure is such that it is detected at a portion, as shown in FIG. 6D or 6E, if the radiation detection means (X-ray detector 4) is very large, the radiation detection means ( There is no need to detect radiation (X-rays) at the center of the X-ray detector 4).

DESCRIPTION OF SYMBOLS 2 ... Stage 3 ... X-ray tube 4 ... X-ray detector 5 ... Detector rotation mechanism 7 ... Stage drive mechanism 7a ... X-axis rectilinear motor 7b ... Y-axis rectilinear motor 7c ... Z-axis rectilinear motor 8 ... Tomographic image calculation part 9 ... Controller C ... Standard circular orbit C _B ... Great circular orbit C _S ... Small circular orbit O ... Object

Claims (7)

A stage on which the object is placed;
A radiation irradiating means and a radiation detecting means arranged to face each other with the stage in between,
A radiation imaging apparatus comprising: an arithmetic unit that calculates a tomographic image based on a plurality of projection images obtained by detecting radiation emitted from the radiation irradiation unit and transmitted through the object by the radiation detection unit. Because
At least one of the radiation irradiation means and the stage is a combination of two or more rectilinear drive mechanisms, and the combined trajectory of the driven parts driven by the respective rectilinear drive mechanisms becomes a trajectory according to a circular trajectory. Combined drive means for driving as a driven part;
Control means for controlling the composite drive means,
The control means includes
A condition that the absolute value of the amount of movement per unit step of each linear drive mechanism in the reversal region is set to a predetermined value or more or “0” having a positive value larger than the movement amount in the reversal region in the case of a circular orbit. Based on the above, each linear drive mechanism is controlled individually to realize a trajectory according to the circular trajectory,
The above-mentioned synthesis is performed by setting a trajectory in a range from a small circular orbit having a half size in a concentric circle of the circular orbit to a large circular orbit having a size twice as large as a concentric circle in the circular orbit as a trajectory according to the circular orbit. A radiation imaging apparatus characterized by controlling a driving means. A stage on which the object is placed;
A radiation irradiating means and a radiation detecting means arranged to face each other with the stage in between,
Computing means for computing a tomographic image based on a plurality of projection images obtained by detecting radiation emitted from the radiation irradiating means and transmitted through the object by the radiation detecting means;
A radiography apparatus comprising :
At least one of the radiation irradiation means and the stage is a combination of two or more rectilinear drive mechanisms, and the combined trajectory of the driven parts driven by the respective rectilinear drive mechanisms becomes a trajectory according to a circular trajectory. Combined drive means for driving as a driven part;
Control means for controlling the composite drive means,
The control means includes
Based on the condition that the absolute value of the movement amount per unit step is equal to or greater than a predetermined value having a positive value or “0”, each linear drive mechanism is controlled to create a trajectory according to the circular trajectory. As well as
The above-mentioned synthesis is performed by setting a trajectory in a range from a small circular orbit having a half size in a concentric circle of the circular orbit to a large circular orbit having a size twice as large as a concentric circle in the circular orbit as a trajectory according to the circular orbit. Control the driving means ,
The composite drive means is composed of two orthogonal drive mechanisms orthogonal to each other,
The control means includes
While the amount of movement per unit step is not less than the predetermined value, the combined drive means is controlled so that the trajectory of the driven part becomes the circular trajectory itself,
Only in the region where the drive direction of one of the rectilinear drive mechanisms is reversed, the movement amount per unit step of the one rectilinear drive mechanism is set to “0”, and similarly, the drive direction of the other rectilinear drive mechanism is reversed. By setting the movement amount per unit step of the other linear drive mechanism only to the region to “0”, each of the linear drive mechanisms is set so that the track of the driven part becomes a track according to the circular track. A radiographic apparatus characterized by controlling each of them. The radiographic apparatus according to claim 1,
The composite drive means is composed of two orthogonal drive mechanisms orthogonal to each other,
The control means includes
While controlling the combined drive means so that the trajectory of the driven part becomes the circular trajectory itself while it is outside the inversion region ,
Only in the region where the drive direction of one of the rectilinear drive mechanisms is reversed, the movement amount per unit step of the one rectilinear drive mechanism is set to a fixed value that is equal to or greater than the predetermined value, and similarly, the drive of the other rectilinear drive mechanism is driven. By setting the absolute value of the movement amount per unit step of the other linear drive mechanism only to the fixed value only in the region where the direction is reversed, the trajectory of the driven part becomes a trajectory according to the circular trajectory. A radiation imaging apparatus, wherein each of the linear drive mechanisms is controlled. The radiographic apparatus according to claim 1,
The composite drive means is composed of two orthogonal drive mechanisms orthogonal to each other,
The trajectory according to the circular trajectory is a trajectory ranging from the small circular trajectory to the great circular trajectory, and a rectangular trajectory,
The control means, when driving corresponding to one side of the rectangular orbit, is driven by setting the amount of movement per unit step by one of the linear drive mechanisms to a fixed value equal to or greater than the predetermined value, The radiation imaging apparatus characterized in that the rectangular trajectory is realized by setting the amount of movement per unit step by the other straight drive mechanism to “0”. The radiographic apparatus according to claim 1,
The composite drive means is composed of two orthogonal drive mechanisms orthogonal to each other,
The trajectory according to the circular trajectory is a trajectory ranging from the small circular trajectory to the great circular trajectory, and a rectangular trajectory,
When the driving corresponding to one side of the rectangular track is performed, the control means sets the absolute value of the amount of movement per unit step by one of the linear drive mechanisms to a fixed value that is equal to or greater than the predetermined value. In addition, the rectangular trajectory is realized by driving by setting the absolute value of the movement amount per unit step by the other linear drive mechanism to the fixed value. In the radiography apparatus in any one of Claims 1-5,
A radiation imaging apparatus comprising: a detection drive unit that drives the radiation detection unit in synchronization with the drive of the driven part by the synthesis drive unit. The radiographic apparatus according to claim 6,
The detection drive means drives the radiation detection means so that the radiation emitted from the radiation irradiation means passes through a point of interest of the object and is detected at the central portion of the radiation detection means. Radiation imaging device.

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