Compensation filter device and x-ray imaging apparatus employing the same

Abstract

The present application is a compensation filter device and an X-ray imaging device capable of moving a compensation filter plate to a desired position using a simple structure and avoiding deterioration of the compensation filter plate. A rotation plate that drives a compensation filter plate (25) is stacked in a vertically overlapping manner, the rotation plate (21) and the compensation filter plate are configured to be able to rotate with a support point as a center, a protrusion (55) is provided on the rotation plate (23), a long hole (57) that fits with the protrusion (55) and allows the protrusion (55) to move is provided on the compensation filter plate, the rotation plate (21) is provided with a protrusion (73), the rotation plate (23) is provided with a groove portion (75), the protrusion (73) and the groove portion interfere with each other to inhibit rotation of the rotation plate due to the rotation angle of the rotation plate (23) with respect to the rotation plate (21) being upper or lower limits, thereby limiting the relative rotation angle to a predetermined range, and interference of the protrusion (73) and the groove portion occurs before the protrusion (55) contacts the end of the long hole.

Description

Technical Field

[0001] This invention relates to a compensation filtering device for driving a compensation filtering plate and an X-ray imaging device using the compensation filtering device. Background Technology

[0002] Conventionally, such compensation filter devices are used in X-ray imaging devices, such as X-ray fluoroscopy cameras, and are installed in the X-ray tube of the X-ray imaging device. Furthermore, the compensation filter device is equipped with a compensation filter plate that is semi-transmissive relative to X-rays, and this compensation filter plate is used to suppress halos, etc. For example, when a part of the subject is more easily transmitted by X-rays compared to other parts, halos may sometimes occur in that part. The compensation filter plate makes the X-rays in such parts semi-transmissive, thus suppressing halos. For this purpose, the compensation filter device has a structure that drives the compensation filter plate to move towards the target location.

[0003] As a conventional structure for a compensation filter device that drives the compensation filter plate to the target location, the following structures can be listed. That is, such as Figure 21 As shown, a conventional compensation filter device 100 includes a gear 101, a compensation filter plate 110, and a gear 111 (for example, Patent Document 1). The gear 101, the compensation filter plate 110, and the gear 111 are stacked sequentially. The gear 101 and the gear 111 are configured to rotate in both directions under the action of a motor (not shown).

[0004] Gear 101 has a protrusion 102 near its outer periphery on its upper surface, and gear 111 has a protrusion 112 near its outer periphery on its lower surface. The compensation filter plate 110 is a thin, generally rectangular plate-like member. A hole Fa is formed at one end of the compensation filter plate 110 to engage with the protrusion 102. Furthermore, an elongated hole Fb is formed at the other end of the compensation filter plate 110, which engages with the protrusion 112 and allows the protrusion 112 to move.

[0005] Furthermore, the gear 101, the compensation filter plate 110, and the gear 111 are stacked in an overlapping manner, with the protrusion 102 engaging with the hole Fa and the protrusion 112 engaging with the elongated hole Fb. Figure 22 This is a top view of the compensation filter device 100 in its initial state. By engaging the protrusion 102 with the hole Fa, the compensation filter plate 110 can rotate around the support portion provided with the hole Fa and the protrusion 102.

[0006] In the compensation filter device 100, with gear 101, compensation filter plate 110, and gear 111 stacked, the rotational and forward / backward movement of compensation filter plate 110 is achieved by appropriately adjusting the rotational direction and angle of gears 101 and 111. When compensation filter plate 110 rotates about the central axis P of compensation filter device 100, gears 101 and 111 rotate in the same direction at the same speed. In this case, compensation filter plate 110 rotates and moves together with gears 101 and 111 about the central axis P.

[0007] While the compensation filter plate 110 moves forward and backward along the face of the gear 101, the gears 101 and 111 rotate in opposite directions. Figure 23 This indicates a state where gear 101 rotates counterclockwise (left-hand) and gear 111 rotates clockwise (right-hand) at the same speed. Through this rotation, protrusion 102 moves counterclockwise along with hole Fa, moving from the position indicated by the dashed line to the position indicated by the solid line. Furthermore, protrusion 112 moves clockwise along with elongated hole Fb, moving from the position indicated by the dashed line to the position indicated by the solid line. At this time, protrusion 112 moves along the length of elongated hole Fb. Therefore, the compensation filter plate 110 maintains an angle relative to the central axis P. Figure 23 Move to the right in the middle. This causes the compensation filter plate 110 to move towards... Figure 23 When moving to the left, gear 101 rotates clockwise and gear 111 rotates counterclockwise at the same speed. This relatively simple structure, which appropriately controls the rotation direction and angle of gears 101 and 111, allows the compensation filter plate 110 to be moved to the desired position by controlling its rotational and forward / backward movements respectively.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent No. 5573648 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] However, in previous examples with such a structure, the following problems exist.

[0013] In conventional structures, when the compensation filter plate 110 moves forward or backward, the distance that the protrusion 112 on gear 111 moves along the elongated hole Fb increases depending on the magnitude of the rotation angle that causes gears 101 and 111 to rotate in opposite directions. Therefore, when the compensation filter plate 110 moves to the right, if the rotation angle of gears 101 and 111 increases, the protrusions 102 and 112 move away from each other, thus increasing their straight-line distance. Therefore, as... Figure 24 As shown, the protrusion 112 contacts one end of the elongated hole Fb (the upper end in the figure), thereby applying a pressing force B1 from the protrusion 112 to the end face of the elongated hole Fb. Since the compensation filter plate 110 is a relatively thin plate-shaped component with low strength, it is possible that the pressing force B1 may cause strain or damage to the compensation filter plate 110.

[0014] On the outside of the elongated hole Fb towards the compensation filter plate 110 ( Figure 24 When the upper side of the protrusion is sufficiently extended, even when the protrusion 112 is moved to its furthest position from the protrusion 102, it is possible to avoid contact between the protrusion 112 and one end of the elongated hole Fb. However, in this case, if the gears 101 and 111 are further rotated in opposite directions, the protrusions 102 and 112 move closer to each other to the right, thus reducing their straight-line distance. As a result, as Figure 25 As shown, protrusion 112 will connect with the other end of elongated hole Fb ( Figure 25 The lower end of the protrusion 112 contacts the end face of the elongated hole Fb, thereby applying a pressing force B2. Therefore, it is difficult to avoid strain or damage to the compensation filter plate 110, which would lead to the deterioration of the compensation filter 110.

[0015] The present invention was made in view of such circumstances, and its object is to provide a compensation filter device that can move the compensation filter plate to a desired position using a simple structure and can more reliably avoid the deterioration of the compensation filter plate, and an X-ray imaging device using the compensation filter device.

[0016] Solution for solving the problem

[0017] The present invention adopts the following structure to achieve this objective.

[0018] That is, the first aspect of the present invention is a compensation filtering device for driving a compensation filter plate, wherein the compensation filtering device includes two rotating members that drive the compensation filter plate by rotational drive, and each of the rotating members has a rotational drive unit that drives the two rotating members to rotate respectively. The two rotating members are stacked vertically overlapping each other. One of the two rotating members and the compensation filter plate are respectively configured to be able to rotate about a support portion. A protrusion is provided in either the other rotating member or the compensation filter plate, and a part that engages with the protrusion is provided in the other rotating member. The protrusion has an elongated hole that allows it to move. One of the two rotating members has a first member, and the other rotating member has a second member. The first member and the second member interfere with each other to suppress the rotation of the two rotating members, thereby limiting the relative rotation angle within the predetermined range, because the relative rotation angle of the other rotating member relative to the first rotating member is an upper or lower limit of a predetermined range. The first member and the second member are configured to generate the interference between the first member and the second member before the protrusion contacts the end of the elongated hole.

[0019] Furthermore, the X-ray imaging apparatus of the second aspect of the present invention includes: an X-ray tube that irradiates an object with X-rays; an X-ray detector that detects X-rays transmitted through the object; an X-ray image generation unit that generates an X-ray image using the detection signal output by the X-ray detector; and a compensation filter device disposed between the X-ray tube and the X-ray detector, wherein the compensation filter device is the compensation filter device of the first aspect of the present invention.

[0020] The effects of the invention

[0021] According to the first aspect of the compensation filtering device of the present invention, two rotating members that drive the compensation filter plate by rotation are stacked one on top of the other, and a rotation drive unit is provided for each rotating member. Therefore, the two rotating members can be driven to rotate in one direction respectively. Furthermore, one of the two rotating members and the compensation filter plate can rotate around a support portion. In addition, either the other rotating member or the compensation filter plate is provided with a protrusion, and the other is provided with an elongated hole that engages with the protrusion and allows the protrusion to move, so that the compensation filter plate can be held at the portion where the protrusion is provided by the other rotating member and can move within the range of the elongated hole. Therefore, when each rotating member is driven to rotate by the respective rotation drive unit, the compensation filter plate held on each rotating member can not only rotate in the rotation direction, but also move within the range of the elongated hole, and the above-mentioned rotation and movement can be combined to move the compensation filter plate to a desired location.

[0022] Furthermore, one of the two rotating members has a first member, and the other rotating member has a second member. The first and second members interfere with each other to suppress the rotation of the two rotating members because the relative rotation angle of the other rotating member relative to the first member is within a predetermined upper or lower limit, thereby limiting the relative rotation angle of the other rotating member relative to the first member to a predetermined range. Moreover, the first and second members are configured to generate interference between the first and second members before the protrusion contacts the end of the elongated hole. With this structure, interference between the first and second members is generated before the protrusion contacts the end of the elongated hole and applies a pressing force to the end face of the elongated hole, suppressing the relative rotation of the two rotating members. Therefore, it is possible to avoid the situation where the protrusion contacts the end of the elongated hole and applies a pressing force to the end face of the elongated hole due to an excessively large relative rotation angle of the other rotating member relative to the first member, which would lead to deterioration of the compensation filter plate. Therefore, a simple structure can be used to move the compensation filter plate to the desired position, and deterioration of the compensation filter plate can be avoided more reliably.

[0023] According to a second aspect of the present invention, an X-ray imaging apparatus includes: an X-ray tube that irradiates an object with X-rays; an X-ray detector that detects X-rays transmitted through the object; an X-ray image generation unit that generates an X-ray image using a detection signal output from the X-ray detector; and a compensation filter device disposed between the X-ray tube and the X-ray detector. This compensation filter device is the same as the compensation filter device of the first aspect of the present invention. Therefore, when each rotating member is driven to rotate using the respective rotation drive unit of the compensation filter device, the compensation filter plate held on each rotating member can not only rotate along the rotation direction but also move within the range of the elongated hole. This rotation and movement can be combined to move the compensation filter plate to a desired location. Furthermore, interference between the first and second members is generated before the protrusion contacts the end of the elongated hole and applies a pressing force to the end face of the elongated hole, suppressing the relative rotation of the two rotating members. Therefore, it is possible to avoid the situation where the protrusion contacts the end of the elongated hole due to an excessively large relative rotation angle between the other rotating component and the first rotating component, thus applying a pressing force to the end face of the elongated hole and causing deterioration of the compensation filter plate. Therefore, it is possible to realize an X-ray imaging device that allows the compensation filter plate to be moved to the desired position using a simple structure, and that more reliably avoids deterioration of the compensation filter plate. Attached Figure Description

[0024] Figure 1 This is a schematic structural diagram and block diagram of the X-ray imaging device and compensation filter device of Example 1.

[0025] Figure 2This is a schematic cross-sectional view of the compensation filter device in Embodiment 1.

[0026] Figure 3 This is an exploded view illustrating the structure of the compensation filter device in Embodiment 1.

[0027] Figure 4 This is a top view showing the structure of the rotating plate and the compensation filter plate in Embodiment 1.

[0028] Figure 5 This is a perspective view showing the main structure of the compensation filter device in Embodiment 1.

[0029] Figure 6 This is a schematic top view showing the initial state of the compensation filter device in Embodiment 1.

[0030] Figure 7 This is a schematic top view showing the state in which each rotating plate rotates in the same direction, according to the compensation filter device of Embodiment 1.

[0031] Figure 8 This is a schematic top view showing the state in which the various rotating plates rotate in opposite directions relative to each other, according to the compensation filter device of Embodiment 1.

[0032] Figure 9 This is a schematic top view of the compensation filter device of Embodiment 1, showing the state in which each rotating plate rotates in opposite directions and the relative rotation angle reaches the upper limit.

[0033] Figure 10 This is a schematic top view of the compensation filter device of Embodiment 1, showing the state in which each rotating plate rotates in opposite directions and the relative rotation angle reaches the lower limit.

[0034] Figure 11 This is a perspective view showing the structure of the rotating plate in Embodiment 2.

[0035] Figure 12 This is a schematic top view showing the initial state of the compensation filter device in Embodiment 2.

[0036] Figure 13 This is a perspective view showing the main structure of the compensation filter device in Embodiment 2.

[0037] Figure 14 This is a schematic top view showing the state in which the various rotating plates rotate in opposite directions relative to each other, according to the compensation filter device of Embodiment 2.

[0038] Figure 15 This is a schematic top view of the compensation filter device of Embodiment 2, showing the state in which each rotating plate rotates in opposite directions and the relative rotation angle reaches the upper limit.

[0039] Figure 16 This is a schematic top view of the compensation filter device of Embodiment 2, showing the state in which each rotating plate rotates in opposite directions and the relative rotation angle reaches the lower limit.

[0040] Figure 17 This is a perspective view showing the structure of the rotating plate and the compensation filter plate in the first modified example.

[0041] Figure 18 This is a top view showing the structure of the rotating plate and the compensation filter plate in the first modified example.

[0042] Figure 19 This is a perspective view showing the main structure of the compensation filter device in the second variation.

[0043] Figure 20 This is a schematic top view showing the structure of the compensation filter device in the second variation.

[0044] Figure 21 This is a three-dimensional diagram showing the structure of a compensation filter device as in previous examples.

[0045] Figure 22 This is a top view showing the structure of the compensation filter device in the previous example.

[0046] Figure 23 This is a top view showing the state in which the compensation filter device, as described in previous examples, causes the gears to rotate in opposite directions.

[0047] Figure 24 This is a top view showing the problem points of the compensation filter device in previous examples.

[0048] Figure 25 This is a top view showing the problem points of the compensation filter device in previous examples.

[0049] Figure 26 This is a top view showing the structure of the compensation filter device for the comparative example.

[0050] Figure 27 This is a top view showing the problem points of the compensation filter device in the comparative example.

[0051] Explanation of reference numerals in the attached figures

[0052] 1. X-ray imaging device; 3. X-ray tube; 5. X-ray detector; 7. Compensation filter; 9. Collimator; 11. Main control unit; 12. Image processing unit; 13. Display unit; 15. Storage unit; 17. Input unit; 21. Rotating plate; 23. Rotating plate; 25. Compensation filter plate; 27. Motor; 29. ​​Motor; 31. Holding member; 33. Holding member; 43. Filtering unit; 45. Support unit; 51. Protrusion; 53. Hole; 55. Protrusion; 57. Elongated hole; 61. Protrusion; 63. Hole; 65. Protrusion; 67. Elongated hole; 71. Rotation angle limiting mechanism; 73. Protrusion; 75. Groove; 77. Wall panel; 79. Wall panel. Detailed Implementation

[0053] Hereinafter, Embodiment 1 of the present invention will be described with reference to the accompanying drawings.

[0054] <Explanation of the overall structure>

[0055] like Figure 1 As shown, the X-ray imaging apparatus 1 of Embodiment 1 includes an X-ray tube 3, an X-ray detector 5, a compensation filter 7, a collimator 9, a main control unit 11, an input unit 13, a storage unit 15, and a display unit 17. The X-ray tube 3 irradiates the subject M with X-rays. The X-ray detector 5 detects the X-rays transmitted from the X-ray tube 3 to the subject M, converts them into electrical signals, and outputs them as X-ray detection signals. As an example of the X-ray detector 5, an FPD (Flat Panel Detector) can be cited. In this embodiment, the direction from the X-ray tube 3 toward the center of the X-ray detector 5 (the X-ray irradiation direction) is defined as the z-direction.

[0056] A compensation filter 7 is installed on the X-ray irradiation side of the X-ray tube 3 to suppress halos, etc. That is, the compensation filter 7 is positioned between the X-ray tube 3 and the X-ray detector 5. The specific structure of the compensation filter 7 will be described later. A collimator 9 is positioned downstream of the compensation filter 7 to control the X-ray irradiation area. The collimator 9 is constructed of an X-ray absorber, such as lead, and the irradiation area of ​​the X-rays irradiated from the X-ray tube 3 is controlled by adjusting the size of the opening of the collimator 9. Alternatively, the collimator 9 can also be positioned upstream of the compensation filter 7. That is, the X-rays irradiated from the X-ray tube 3 pass through the compensation filter 7 and the collimator 9, and are then detected by the X-ray detector 5 after passing through the subject M.

[0057] The main control unit 11 includes, for example, an information processing unit such as a central processing unit (CPU). The main control unit 11 provides overall control over the various structures of the X-ray imaging device 1, taking the X-ray tube 3 and X-ray detector 5 as examples. The main control unit 11 also includes an image processing unit 12. The image processing unit 12 is located after the X-ray detector 5 and generates an X-ray image based on the X-ray detection signal output from the X-ray detector 5. In this embodiment, the image processing unit 12 corresponds to the X-ray image generation unit.

[0058] Display unit 13 displays X-ray images generated by image processing unit 12 and various information related to X-ray imaging device 1. Examples of display units 13 include liquid crystal monitors or high-resolution displays. Storage unit 15 writes and stores various X-ray images generated by image processing unit 12 and various information related to the operation of X-ray device 1. The stored information is read out as needed and output to display unit 13 via main control unit 11. Storage unit 15 is constructed using a storage medium, such as non-volatile memory.

[0059] The input unit 17 is used to input operator instructions related to the operation of the X-ray imaging device 1, and the main control unit 11 performs overall control according to the instructions input by the technician into the input unit 17. Examples of operating devices provided in the input unit 17 include a keyboard input panel, a touch input panel, a mouse, a dial, a toggle switch, and a push-button switch.

[0060] <Structure of the Compensation Filter Device>

[0061] Here, the structure of the compensation filter device 7 will be explained. For example... Figure 2 and Figure 3 As shown, the compensation filter device 7 includes two rotating plates 21 and 23, a compensation filter plate 25, two motors 27 and 29, two holding members 31 and 33, two spacers 35 and 37, and a lower substrate 39 and an upper substrate 41 that house the above-described structure. For example, two support pillars 43 are erected between the lower substrate 39 and the upper substrate 41. Furthermore, for example, the rotating plates 21 and 23, the holding members 31 and 33, the spacers 35 and 37, the lower substrate 39, and the upper substrate 41 each have a circular opening at their center. X-rays irradiated from the X-ray tube 3 irradiate the subject M through these openings.

[0062] A compensation filter device 7 is constructed by stacking rotating plates 21 and 23 one on top of the other and placing a compensation filter plate 25 between them. A motor 27 is mounted on the side of the rotating plate 21 and drives it to rotate about the axis of the central axis P (the axis in the z-direction). The motor 27 is configured not to move with the rotating plate 21. That is, the position of the motor 27 remains unchanged while driving the rotating plate 21 to rotate. A motor 29 is mounted on the side of the rotating plate 23 and drives it to rotate about the axis of the central axis P. The motor 29 is also configured not to move with the rotating plate 23. The rotating plates 21 and 23 correspond to the rotating members of this embodiment.

[0063] The lower substrate 39 is disposed on the side of the compensation filter device 7 near the X-ray tube 3. Figure 2 The lower side of the upper substrate 41 is disposed on the side of the compensation filter device 7 near the X-ray detector 7. Figure 2 (The upper side of the middle).

[0064] In this embodiment, the compensation filter plate 25 consists of a pair of compensation filter plates 25A and 25B. The compensation filter plates 25A and 25B are arranged opposite each other with a central axis P between them. The compensation filter plates 25A and 25B are configured to move forward and backward in directions toward each other and in directions away from each other using the structure described later.

[0065] A retaining member 31 is disposed inside the rotating plate 21 to retain the inner side of the rotating plate 21 in a manner that prevents the rotating plate 21 from moving in any direction other than the rotation direction. Similarly, a retaining member 33 is disposed inside the rotating plate 23 to retain the inner side of the rotating plate 23 in a manner that prevents the rotating plate 23 from moving in any direction other than the rotation direction. A spacer 35 is disposed between the rotating plate 21 and the lower substrate 39 to prevent contact between the rotating plate 21 and the lower substrate 39. A spacer 37 is disposed between the rotating plate 23 and the upper substrate 41 to prevent contact between the rotating plate 23 and the upper substrate 41.

[0066] like Figure 3As shown, the lower side of the end (outer periphery) of the retaining member 31 is a recess 31a. In this embodiment, the recess 31a is annular. That is, the retaining member 31 contacts the spacer 35 at a portion other than the end, and the inner side of the rotating plate 21 is held by the retaining member 31 by fitting the rotating plate 21 into the recess 31a between the retaining member 31 and the spacer 35 at the end. Furthermore, the upper side of the end of the retaining member 33 is a recess 33a. In this embodiment, the recess 33a is annular. The retaining member 33 contacts the spacer 37 at a portion other than the end, and the inner side of the rotating plate 23 is held by the retaining member 33 by fitting the rotating plate 23 into the recess 33a between the retaining member 33 and the spacer 37 at the end.

[0067] like Figure 2 As shown, the lower retaining member 31 contacts the compensation filter plate 25, and the retaining member 31 guides the compensation filter plate 25. The compensation filter plate 25 is guided and moved by the retaining member 31 while in contact with the upper surface of the retaining member 31.

[0068] With the spacer 35 mounted on the lower substrate 39, two rotating plates 21 and 23, a compensation filter plate 25, two motors 27 and 29, two holding members 31 and 33, and the spacer 37 are mounted, and the support columns 43 are erected. The compensation filter device 7 is completed by mounting the upper substrate 41 on the erected support columns 43.

[0069] Next, use Figures 4-6 Explain the main structure of the compensation filter device 7. Figure 4 These are top views showing the rotating plate 21, rotating plate 23, and compensation filter plate 25, which are the main structures of the compensation filter device 7. Figure 5 It is a three-dimensional diagram showing the state in which the rotating plate 21, the rotating plate 23 and the compensation filter plate 25 are superimposed in the vertical direction (z direction). Figure 6 This is a top view showing the overlapping state of rotating plate 21, rotating plate 23, and compensation filter plate 25. Additionally, Figure 6 The initial positions of rotating plate 21, rotating plate 23, and compensation filter plate 25 are shown. Additionally, Figures 1-3 The compensation filter 7 indicates the view when viewed from the front. Figure 5 This is a perspective view of the compensation filter device 7 as seen from the left side.

[0070] like Figure 4 and Figure 5As shown, compensation filter plates 25A and 25B each include a filter portion 43 and a support portion 45. The filter portion 43 and the support portion 45 are constructed from thin, plate-like members. In this embodiment, compensation filter plates 25A and 25B are generally rectangular, and the filter portion 43 is semi-circular, but the shapes can be appropriately modified. The filter portion 43 is made of a material that is semi-transparent to X-rays; copper is an example of such a material.

[0071] The filter section 43 is disposed on the side of the compensation filter plate 25 closest to the central axis P. Furthermore, by bringing the compensation filter plates 25A and 25B close together and abutting against each other, the filter section 43 disposed on the compensation filter plate 25A and the filter section 43 disposed on the compensation filter plate 25B abut against each other, forming a circular filter section 43. The shape of the filter section 43 is not limited to a semi-circle; it can be a rectangular shape, a roughly semi-circular shape, or other suitable shapes.

[0072] The support portion 45 is configured as an arc portion surrounding the semi-circular filter portion 43. Examples of materials constituting the support portion 45 include iron. In this embodiment, the rotating plate 21 and the rotating plate 23 have annular shapes, and examples of materials constituting the rotating plate 21 and the rotating plate 23 include resin or metal. Furthermore, the rotating plate 21 and the rotating plate 23 are plate-shaped members that are thicker than the compensation filter plate 25.

[0073] Here, the structure that allows the compensation filter plate 25 to move will be described. First, a protrusion 51 is provided on the upper surface of the rotating plate 21, and a hole 53 is provided on the compensation filter plate 25A. The protrusion 51 is configured to engage with the hole 53, such that by engaging the protrusion 51 with the hole 53, the compensation filter plate 25A and the rotating plate 21 can rotate around the support portion where the protrusion 51 and the hole 53 are formed.

[0074] Furthermore, a protrusion 55 is provided on the lower surface of the rotating plate 23, and an elongated hole 57 is provided on the compensation filter plate 25A. The elongated hole 57 is configured to allow the protrusion 55 to fit into it, and the protrusion 55 is movable. With this structure, the compensation filter plate 25A is held by the rotating plate 23 at the location where the protrusion 55 is provided and can move within the range of the elongated hole 57. In the compensation filter plate 25A, a hole 53 is provided on one end side of the compensation filter plate 25A (…). Figure 4 The lower side of the middle Figure 5 The elongated hole 57 is located on the other end side (near the front side of the middle). Figure 4 (The upper side of the middle).

[0075] Therefore, by using motors 27 and 29 to drive the rotating plates 21 and 23 to rotate respectively, the compensation filter plate 25A can be rotated and moved about the central axis P in accordance with its rotation direction and rotation angle, and can also move forward and backward toward the central axis P. Moreover, by combining this rotational movement and forward and backward movement, the compensation filter plate 25A can be moved to the desired location.

[0076] The compensation filter plate 25B also has the same structure as the compensation filter plate 25A. That is, a protrusion 61 is provided on the lower surface of the rotating plate 23, and a hole 63 is provided on the compensation filter plate 25B. The protrusion 61 is configured to fit into the hole 63, so that by fitting the protrusion 61 into the hole 63, the compensation filter plate 25B and the rotating plate 23 can rotate around the support portion where the protrusion 61 and the hole 63 are formed.

[0077] Furthermore, a protrusion 65 is provided on the upper surface of the rotating plate 21, and an elongated hole 67 is provided on the compensation filter plate 25B. The elongated hole 67 is configured to fit the protrusion 65, and the protrusion 65 is movable. With this structure, the compensation filter plate 25B is held by the rotating plate 21 at the location where the protrusion 65 is provided and can move within the range of the elongated hole 67. In the compensation filter plate 25B, a hole 63 is provided on one end side of the compensation filter plate 25B (…). Figure 4 The lower side of the middle Figure 5 The elongated hole 67 is located on the other end side (near the front side of the middle). Figure 4 (The upper side of the middle).

[0078] Therefore, by using motors 27 and 29 to drive the rotating plates 21 and 23 to rotate respectively, the compensation filter plate 25B can rotate and move around the central axis P in accordance with its rotation direction and rotation angle, and move forward and backward toward the central axis P. Moreover, by combining this rotational movement and forward and backward movement, the compensation filter plate 25B can be moved to the desired location. In addition, the compensation filter plates 25A and 25B are arranged in a point-symmetric manner with respect to the central axis P, and move relative to each other with respect to the central axis P. That is, by moving the compensation filter plates 25A and 25B forward and backward, the compensation filter plate 25 as a whole can be moved to open and close.

[0079] Furthermore, the compensation filter device 7 of Embodiment 1 includes a rotation angle limiting mechanism 71 on the rotating plate 21 and the rotating plate 23. The rotation angle limiting mechanism 71 restricts the rotational movement of the rotating plate 21 and the rotating plate 23, thereby limiting the relative rotation angle of the rotating plate 23 with respect to the rotating plate 21 within a predetermined range. In Embodiment 1, the rotation angle limiting mechanism 71 includes a protrusion 73 provided on the upper surface of the rotating plate 21 and a groove 75 provided on the rotating plate 23. When the rotating plate 21 and the rotating plate 23 are overlapped, the protrusion 73 is configured to fit into the groove 75. The groove 75 is configured to have a shape (here, an arc-shaped trajectory) along the trajectory of the protrusion 73 as it moves through the rotating plate 21. The end face of one end of the groove 75 ( Figure 4 The right end face of the groove 75 is designated as end face 75a. Furthermore, the end face of the other end of the groove 75 ( Figure 4 The left end face is designated as end face 75b. The protrusion 73 corresponds to the first component of this embodiment, and the groove 75 corresponds to the second component of this embodiment.

[0080] The length of the groove 75 is appropriately determined in accordance with the range of the relative rotation angle of the limiting rotating plate 23 relative to the rotating plate 21 (denoted as the "relative rotation range" in this embodiment). The relative rotation range is also predetermined in accordance with the range of allowable forward and backward movement of the compensation filter plate 25. In this embodiment, the position of the protrusion 73 and the length of the groove 75 are determined in such a way that the protrusion 73 abuts against the end face 75a of the groove 75 when the compensation filter plate 25A and the compensation filter plate 25B are close to each other and abut against each other.

[0081] In this embodiment, when the rotating plate 23 rotates clockwise relative to the rotating plate 21, the relative rotation angle (hereinafter referred to as "relative rotation angle") of the rotating plate 23 relative to the rotating plate 21 is set to a positive value. Conversely, when the rotating plate 23 rotates counterclockwise relative to the rotating plate 21, the relative rotation angle is set to a negative value. For example, when the rotating plate 21 rotates 20° clockwise and the rotating plate 23 rotates 60° clockwise, the relative rotation angle is +40°. Furthermore, as another example, when the rotating plate 21 rotates 20° clockwise and the rotating plate 23 rotates 30° counterclockwise, the rotating plate 23 rotates 50° counterclockwise relative to the rotating plate 21, therefore the relative rotation angle is -50°.

[0082] Furthermore, the structures of elongated holes 57 and 67 are determined accordingly to the structure of the rotation angle limiting mechanism 71. Specifically, the length and position of elongated hole 57 are determined such that, when the compensation filter plate 25A moves forward or backward, protrusion 73 moves to abut against the end face 75a or 75b of groove 75 before protrusion 55 contacts the end face of elongated hole 57. Similarly, the length and position of elongated hole 67 are determined such that, when the compensation filter plate 25B moves forward or backward, protrusion 73 moves to abut against the end face 75a or 75b of groove 75 before protrusion 65 contacts the end face of elongated hole 67.

[0083] <Explanation of the operation of the compensation filter board>

[0084] Here, use Figures 6-10 Explain the operation of the compensation filter plate 25 when rotating plate 21 and rotating plate 23 are rotated and moved respectively. Figures 6-10 These are schematic top views showing the operating modes of the compensation filter plate 25 when the rotating plate 21 and the rotating plate 23 are rotated respectively. Figure 6 This is a schematic top view of the compensation filter device 7 in its initial state. In the initial state, the protrusion 73 is located near the center of the groove 75. Furthermore, the relative rotation angle in the initial state is set to 0°.

[0085] First, the operation of rotating and moving the compensation filter plates 25 separately will be explained. When rotating and moving the compensation filter plates 25 separately, rotating plates 21 and 23 rotate in the same direction at the same speed. In this case, since rotating plates 21 and 23 rotate at the same angle, their relative rotation angle is 0°.

[0086] As an example, when rotating plate 21 and rotating plate 23 are rotated 90° to the right, a schematic top view of the compensation filter device 7 is shown below. Figure 7 As shown. The protrusions 51, 65, and 73 on the rotating plate 21 rotate 90° clockwise together with the rotating plate 21. Furthermore, the protrusions 55, 61, and groove 75 on the rotating plate 23 rotate 90° clockwise together with the rotating plate 23.

[0087] Compensation filter plate 25A is supported on protrusion 51 of rotating plate 21 that engages with hole 53, and compensation filter plate 25B is supported on protrusion 61 of rotating plate 23 that engages with hole 63. Furthermore, since the relative rotation angle is 0°, the relative position of protrusion 73 relative to groove 75 remains unchanged in rotation angle limiting mechanism 71. Additionally, since the relative rotation angle is 0°, the relative positions of protrusion 55 relative to elongated hole 57 and protrusion 65 relative to elongated hole 67 also remain unchanged. As a result, as... Figure 7As shown, compensation filter plates 25A and 25B rotate 90° clockwise around the central axis P while maintaining a constant distance from the central axis P. This causes rotating plates 21 and 23 to rotate in the same direction at the same speed. Corresponding to the rotation direction and angle of rotating plates 21 and 23, compensation filter plates 25 rotate around the central axis P while maintaining a constant distance from the central axis P.

[0088] Next, the operation of moving the compensation filter plate 25 forward and backward will be explained. While moving the compensation filter plate 25 forward and backward toward the central axis P without rotating it relative to the central axis P, the rotating plates 21 and 23 rotate in opposite directions at the same speed. At this time, the absolute values ​​of the rotation angles of the rotating plates 21 and 23 are equal. Therefore, the absolute value of the relative rotation angle is twice the rotation angle of the rotating plates 21 and 23.

[0089] Here, we will describe the action of moving the compensation filter plate 25 closer to the central axis P during the forward and backward movement process. Figure 8 A schematic top view of the compensation filter device 7 is shown, in which the rotating plates 21 and 23 are rotated in opposite directions to the extent that the protrusion 73 in the rotation angle limiting mechanism 71 has not moved to the end of the groove 75. In this case, the rotating plate 21 is rotated to the left by an angle H from its initial state, and the rotating plate 23 is rotated to the right by an angle H. In this case, the rotating plate 23 rotates relative to the rotating plate 21 in the right-hand direction with a rotation angle of 2H. That is, in this case, the relative rotation angle is "2H".

[0090] The protrusions 51, 65, and 73 on the rotating plate 21 rotate and move together with the rotating plate 21 from the initial state in a left-hand direction with a rotation angle H. Similarly, the protrusions 55, 61, and groove 75 on the rotating plate 23 rotate and move together with the rotating plate 23 from the initial state in a right-hand direction with a rotation angle H. Therefore, in the rotation angle limiting mechanism 71, the protrusion 73 moves relative to the groove 75 in a right-hand direction. The distance the protrusion 73 moves relative to the groove 75 is proportional to the magnitude of the relative rotation angle (here, 2H). Furthermore, in... Figure 8 In the figures, the initial positions of protrusion 51 and hole 53 are indicated by dashed lines with reference numeral G1. Furthermore, the initial positions of protrusion 61 and hole 63 are indicated by dashed lines with reference numeral G2.

[0091] In addition, such as Figure 8As shown, by rotating protrusion 51 clockwise, protrusion 55 rotates counterclockwise, thereby increasing the distance between protrusions 51 and 55 when viewed from above. At this time, in the compensation filter plate 25A, hole 53 is supported by protrusion 51. Therefore, the change in the distance between protrusion 55 and protrusions 51 and 55, which engages with the elongated hole 57, corresponds to the movement within the elongated hole 57. Here, because the distance between protrusions 51 and 55 increases, protrusion 55 moves towards the other end of the elongated hole 57 (…). Figure 8 The compensation filter plate 25A moves towards the central axis P while maintaining its angle relative to the central axis P. The distance traveled by the compensation filter plate 25A is determined accordingly based on the magnitude of the relative rotation angle.

[0092] The compensation filter plate 25B also moves in the same manner as the compensation filter plate 25A. That is, as... Figure 8 As shown, by rotating protrusion 61 counterclockwise and protrusion 65 clockwise, the distance between protrusions 61 and 65 when viewed from above increases. Therefore, the change in distance between protrusion 65, which engages with elongated hole 67, and protrusions 61 and 65 corresponds to the change in distance towards the other end of elongated hole 67. As a result, compensation filter plate 25B moves closer to central axis P while maintaining its angle relative to central axis P. That is, compensation filter plate 25A and compensation filter plate 25B move closer to each other.

[0093] In addition, from Figure 8 The state shown further becomes such that rotating plate 21 and rotating plate 23 rotate in opposite directions to each other. Figure 9 The state shown. Figure 9 A schematic top view of the compensation filter device 7 is shown, in which the rotating plates 21 and 23 are rotated in opposite directions to the extent that the protrusion 73 in the rotation angle limiting mechanism 71 moves to the end of the groove 75. In this case, the rotating plate 21 is rotated to the left by an angle K from its initial state, and the rotating plate 23 is rotated to the right by an angle K. In this case, the rotating plate 23 rotates relative to the rotating plate 21 in the right-hand direction by a rotation angle of 2K. That is, in this case, the relative rotation angle is "2K".

[0094] The protrusions 51, 65, and 73 on the rotating plate 21 rotate and move together with the rotating plate 21 from the initial state in a left-hand direction, with a rotation angle K. Similarly, the protrusions 55, 61, and groove 75 on the rotating plate 23 rotate and move together with the rotating plate 23 from the initial state in a right-hand direction, with a rotation angle K. Therefore, in the rotation angle limiting mechanism 71, the protrusion 73 moves relative to the groove 75 in a right-hand direction and contacts the end face 75a of one end of the groove 75.

[0095] In this embodiment, the position of the end face 75a of the groove 75 (the position of the right end of the groove 75) is predetermined in such a way that the compensation filter plate 25A and the compensation filter plate 25B are brought closer together and abutted when the relative rotation angle is 2K. Therefore, by moving the protrusion 51 in a right-hand rotation direction by a rotation angle K and moving the protrusion 55 in a left-hand rotation direction by a rotation angle K, the distance between the protrusions 51 and 55 when viewed from above is maximized. Therefore, the protrusion 55, which engages with the elongated hole 57, moves toward one end of the elongated hole 57. As a result, the compensation filter plate 25A moves further toward the central axis P while maintaining its angle relative to the central axis P, and abuts against the central axis P when viewed from above.

[0096] Furthermore, by causing protrusion 61 to rotate counterclockwise and protrusion 65 to rotate clockwise, the distance between protrusions 61 and 65 when viewed from above is maximized. Therefore, protrusion 65, which engages with the elongated hole 67, moves toward one end of the elongated hole 67. As a result, the compensation filter plate 25B, while maintaining its angle relative to the central axis P, moves further toward the central axis P, and abuts against the central axis P when viewed from above. That is, compensation filter plates 25A and 25B move toward the central axis P respectively and abut against each other.

[0097] exist Figure 9 In the shown state, by abutting the protrusion 73 against the end face 75a of the groove 75, the rotating plate 23 is prevented from rotating further relative to the rotating plate 21 in the right-hand direction. That is, since the rotation angle limiting mechanism 71 with the protrusion 73 and the groove 75 is used to limit the relative rotation drive of the rotating plate 23 relative to the rotating plate 21, the upper limit of the relative rotation angle is limited to 2K.

[0098] Furthermore, in the structure of Embodiment 1, when the rotating plate 23 is rotated relative to the rotating plate 21 in a right-handed direction, before the protrusion 55 moves to the other end side in the elongated hole 57 and reaches the end face 57a of the elongated hole 57, the protrusion 73 moves to one end side and contacts the end face 75a of the groove 75. In other words, the magnitude of the relative rotation angle required for the protrusion 55 to contact the end face 57a of the elongated hole 57 is greater than the magnitude K2 of the relative rotation speed K2 that the rotating plate 23 can substantially rotate relative to the rotating plate 21.

[0099] Therefore, even when a force is applied that causes the rotating plate 23 to rotate excessively to the right relative to the rotating plate 21, the relative rotation angle will not become larger than K2 because the excessive right-hand rotation of the rotating plate 23 relative to the rotating plate 21 is limited by the protrusion 73 and the groove 75. As a result, it is possible to avoid the situation where the protrusion 55 moves excessively toward one end of the elongated hole 57 and comes into contact with the end face 57a, thereby applying pressure to the end face 57a. Therefore, it is possible to prevent the compensation filter plate 25A from deteriorating due to the application of such pressure.

[0100] The same effect of preventing the deterioration of the compensation filter plate 25A can be achieved in the compensation filter plate 25B. Specifically, when the rotating plate 23 rotates relative to the rotating plate 21 in a clockwise direction, before the protrusion 65 moves to the other end of the elongated hole 67 and reaches the end face 67a of the elongated hole 67, the protrusion 73 moves to one end and contacts the end face 75a of the groove 75. As a result, the situation where the protrusion 65 moves excessively to the other end of the elongated hole 67 and contacts the end face 67a, thus avoiding applying pressure to the end face 67a, can be prevented. Therefore, the deterioration of the compensation filter plate 25B caused by the application of such pressure can be prevented.

[0101] Furthermore, the action of moving the compensation filter plate 25 away from the central axis P during the forward and backward movement process is explained. Figure 10 A schematic top view of the compensation filter device 7 is shown, in which the rotating plates 21 and 23 are rotated in opposite directions to each other and retract from the central axis P to the extent that the protrusion 73 in the rotation angle limiting mechanism 71 moves to the end of the groove 75. In this case, the rotating plate 21 is rotated clockwise by an angle L from the initial state, and the rotating plate 23 is rotated counterclockwise by an angle L. In this case, the rotating plate 23 rotates counterclockwise relative to the rotating plate 21 by a rotation angle of 2L. That is, in this case, the relative rotation angle is "-2L". Furthermore, in this embodiment, the position of the end face 75b of the groove 75 (the position of the left end of the groove 75) is predetermined in such a way that the protrusion 73 contacts the end face 75b when the relative rotation angle is "-2L".

[0102] The protrusions 51, 65, and 73 on the rotating plate 21 rotate together with the rotating plate 21 from the initial state in a clockwise direction with a rotation angle L. Furthermore, the protrusions 55, 61, and groove 75 on the rotating plate 23 rotate together with the rotating plate 23 from the initial state in a counterclockwise direction with a rotation angle L. Moreover, in the rotation angle limiting mechanism 71, the protrusion 73 moves relative to the groove 75 in a leftward direction and contacts the end face 75b on the other end side of the groove 75.

[0103] By moving protrusion 51 clockwise by a rotation angle L and protrusion 55 counterclockwise by a rotation angle L, the distance between protrusions 51 and 55 when viewed from above is reduced. Therefore, protrusion 55, which engages with elongated hole 57, faces the other end of elongated hole 57. Figure 10 The lower side of the filter plate 25A moves away from the central axis P while maintaining its angle relative to the central axis P.

[0104] Furthermore, by rotating protrusion 61 counterclockwise and protrusion 65 clockwise, the distance between protrusions 61 and 65 when viewed from above is reduced. Therefore, protrusion 65, which engages with elongated hole 67, moves toward the other end of elongated hole 67. As a result, compensation filter plate 25B retracts away from central axis P while maintaining its angle relative to central axis P. That is, compensation filter plate 25A and compensation filter plate 25B retract in opposite directions away from central axis P, respectively.

[0105] exist Figure 10 In the shown state, by abutting the protrusion 73 against the end face 75b of the other end of the groove 75, the rotating plate 23 is prevented from rotating further to the left relative to the rotating plate 21. That is, since the rotational angle limiting mechanism 71 with the protrusion 73 and the groove 75 limits the relative rotational drive of the rotating plate 23 relative to the rotating plate 21, the lower limit of the relative rotation angle is limited to "-2L". Thus, the rotational angle limiting mechanism 71 of Embodiment 1 limits the range of the relative rotation angle to an upper limit of 2K and a lower limit of -2L. By limiting the range of the relative rotation angle, the range in which the protrusion 55 can move in the elongated hole 57 and the range in which the protrusion 65 can move in the elongated hole 67 are also limited to predetermined ranges.

[0106] Furthermore, in the structure of Embodiment 1, when the rotating plate 23 is rotated relative to the rotating plate 21 in a left-handed direction, the protrusion 55 extends towards one end of the elongated hole 57 ( Figure 10 Before the protrusion 73 moves to the other end face 57b of the elongated hole 57 (the lower side of the hole) and reaches the other end face 57b, the protrusion 73 moves towards the other end face (the lower side of the hole). Figure 10 The protrusion 55 moves to contact the end face 75b of the groove 75. In other words, the absolute value of the relative rotation angle required for the protrusion 55 to contact the end face 57b of the elongated hole 57 is greater than the absolute value (L2) of the lower limit of the relative rotation speed "-L2" that the rotating plate 23 can actually rotate relative to the rotating plate 21.

[0107] Therefore, even when a force is applied that causes the rotating plate 23 to rotate excessively to the left relative to the rotating plate 21, the relative rotation angle will not become smaller than -L2 because the excessive leftward rotation of the rotating plate 23 relative to the rotating plate 21 is limited by the protrusion 73 and the groove 75. As a result, it is possible to avoid the situation where the protrusion 55 moves excessively towards the other end of the elongated hole 57 and comes into contact with the end face 57b, thereby applying pressure to the end face 57b. Therefore, it is possible to prevent the compensation filter plate 25A from deteriorating due to the application of such pressure.

[0108] The same effect of preventing the deterioration of the compensation filter plate 25A can be achieved in the compensation filter plate 25B. Specifically, when the rotating plate 23 rotates counterclockwise relative to the rotating plate 21, before the protrusion 65 moves towards one end of the elongated hole 67 and reaches the end face 67b of the elongated hole 67, the protrusion 73 moves towards the other end and contacts the end face 75b of the groove 75. As a result, the situation where the protrusion 65 moves excessively towards one end of the elongated hole 67 and contacts the end face 67b, thus avoiding applying pressure to the end face 67b, can be prevented. Therefore, the deterioration of the compensation filter plate 25B caused by the application of such pressure can be prevented.

[0109] When the compensation filter plate 25 is rotated about the central axis P and moved forward and backward relative to the central axis P, the actions of driving the rotating plate 21 and the rotating plate 23 to rotate in the same direction according to the angle of rotation of the compensation filter plate 25 and the actions of driving the rotating plate 21 and the rotating plate 23 to rotate in opposite directions according to the distance of forward and backward movement of the compensation filter plate 25 are combined.

[0110] In this embodiment, the rotating plates 21 and 23 are equipped with a rotation angle limiting mechanism 71, which allows the rotating plates 21 and 23 to rotate infinitely in the same direction, while limiting the relative rotation angle within a predetermined range for rotation in opposite directions. Therefore, the compensation filter plate 25 can be freely rotated and moved, and adverse conditions caused by excessive forward and backward movement of the compensation filter plate 25 can be avoided.

[0111] That is, in a structure in which the protrusion 55 provided on the rotating plate 21 moves inside the elongated hole 57 of the compensating filter plate 25 in accordance with the distance of its forward and backward movement, the protrusion 73 of the rotation angle limiting mechanism 71 contacts the end face 75a or end face 75b of the groove 75 before the protrusion 55 on the rotating plate 21 contacts the end face 57a or end face 57b of the elongated hole 57 of the compensating filter plate 25. By making the protrusion 73 contact the end face 75a or end face 75b of the groove 75, the further rotation of the rotating plate 21 and the rotating plate 23 is suppressed, and the relative rotation angle becomes outside a predetermined range. Therefore, the further forward and backward movement of the compensating filter plate 25 can be prevented. As a result, the situation where the protrusion 55 exerts pressure on the end face 57a or end face 57b of the elongated hole 57 can be avoided, and the situation where the compensating filter plate 25 is strained or damaged due to such pressure can be prevented.

[0112] The protrusion 73 and the groove 75 are provided on the rotating plate 21 or rotating plate 23, which has a greater thickness and strength than the compensation filter plate 25. Therefore, even when the protrusion 73 contacts the end face 75a or end face 75b of the groove 75 and applies pressure, strain or breakage of the rotating plate 21 or rotating plate 23 can be avoided. Therefore, by providing the rotation angle limiting mechanism 71 on the rotating plate 21 and rotating plate 23, deterioration of the compensation filter plate 25 and the components constituting the compensation filter device 7 can be avoided.

[0113] Furthermore, the rotation angle limiting mechanism 71 is provided on the rotating plate 21 or the rotating plate 23. That is, the rotation angle limiting mechanism 71 uses a mechanical structure (hardware) to limit the relative rotation angle of the rotating plate 23 relative to the rotating plate 21 within a predetermined range. When the relative rotation angle of the rotating plate 23 relative to the rotating plate 21 is limited within the predetermined range by software control, such as a computer, it is possible that due to software malfunctions, the relative rotation angle of the rotating plate 23 cannot be reliably limited. In addition, it is also possible that a time delay occurs before the software signal is transmitted to the mechanism that drives the rotating plate 23 or the other rotating plate to limit the relative rotation of the rotating plate 23, resulting in a delay in the action of limiting the rotation of the rotating plate 23, and the protrusion 55 contacts and presses the end face 57a or end face 57b of the elongated hole 57.

[0114] In contrast, the rotation angle limiting mechanism 71 of this embodiment uses a mechanical structure such as the protrusion 73 and the groove 75 to physically limit the relative rotation angle of the rotating plate 23, thus reliably limiting the relative rotation angle of the rotating plate 23 relative to the rotating plate 21 within a predetermined range. Therefore, it is possible to reliably prevent the compensation filter plate 25 from deteriorating due to strain or other factors.

[0115] Furthermore, in the compensation filter device 7 of this embodiment, even with a structure having multiple compensation filter plates 25A and 25B, deterioration of the compensation filter plates 25A or 25B caused by mutual interference between the compensation filter plates can be avoided. Figure 21 and Figure 22 In the conventional compensation filter device 100 shown, the number of built-in compensation filter plates 110 is one. Therefore, in order for multiple compensation filter plates 110 to act on X-rays, it is necessary to arrange a number of compensation filter devices 100, corresponding to the number of compensation filter plates 110, stacked in the z-direction. As a result, this leads to the problem of device enlargement.

[0116] In the conventional compensation filter device 100, as a structure to avoid this problem, such as Figure 26 As shown, a comparative example is illustrated by a structure in which multiple compensation filter plates 110 are arranged opposite each other on a plane orthogonal to the z-direction (xy-plane) and driven to move closer to each other to control the opening and closing of the compensation filter plates. In this comparative example structure, by moving the multiple compensation filter plates 110 forward and backward toward the central axis P, the multiple compensation filter plates 110 can act on X-rays even when using a single compensation filter device 100. However, in the structure where the multiple compensation filter plates 110 are moved closer to each other, as... Figure 27 As shown, due to excessive rotation of gears 101 and 111 in opposite directions, the compensation filter plates 110 will come into contact with each other at the central portion and exert a pressing force St due to further mutual pressing. Since the compensation filter plates 110 have a lower strength structure compared to gears 101, a new problem will arise where the compensation filter plates 110 deteriorate due to this pressing force St.

[0117] In the compensation filter device 7 of this embodiment, the relative rotation angle is limited to a predetermined range by including a rotation angle limiting mechanism 71. Since the distance the compensation filter plate 25A and the compensation filter plate 25B move forward and backward is determined accordingly with the relative rotation angle, it is possible to prevent the compensation filter plate 25A and the compensation filter plate 25B from moving too far forward and backward by limiting the relative rotation angle. In this embodiment, since the upper limit of the relative rotation angle is limited to 2K, the movement of the compensation filter plate 25A and the compensation filter plate 25B closer together can be controlled as follows: Figure 9 The state where the compensation filter plates 25A and 25B are in contact with each other at the central axis P is suppressed. Therefore, the compensation filter plates 25A and 25B are prevented from contacting each other and moving further by pressing against each other. Thus, in the compensation filter device 7 equipped with compensation filter plates 25A and 25B, the condition where compensation filter plates 25A and 25B deteriorate due to interference can be avoided.

[0118]

Example 2

[0119] Next, Embodiment 2 of the present invention will be described. In Embodiment 2, the same reference numerals are used for structures common to Embodiment 1, and detailed descriptions are omitted. The rotation angle limiting mechanism 71A of Embodiment 2 will be described. The overall structure of the X-ray imaging device of Embodiment 2 is similar to that of Embodiment 1. Figure 1 The overall structure of the X-ray imaging device 1 shown in Embodiment 1 is basically the same. On the other hand, the structure of the rotation angle limiting mechanism 71, which limits the relative rotation angle of the rotating plate 23 with respect to the rotating plate 21, differs between Embodiment 1 and Embodiment 2.

[0120] Figure 11 This is a diagram showing the rotating plate 21A and rotating plate 23A in Embodiment 2. Figure 11 In the text, the surface below the rotating plate 21A is referred to as the surface side. Figure 12 This is a top view showing the overlapping state of rotating plate 21A, rotating plate 23A and compensation filter plate 25 in the compensation filter device 7A of Embodiment 2.

[0121] Figure 13 This is a perspective view showing the state in which the rotating plate 21A, rotating plate 23A, and compensation filter plate 25 of Embodiment 2 overlap in the vertical direction (z direction). Furthermore, Figure 12 The positions of the rotating plate 21A, rotating plate 23A, and compensation filter plate 25 in the initial state are indicated.

[0122] like Figures 11-13 As shown, the rotation angle limiting mechanism 71A of Embodiment 2 includes a wall plate 77 and a wall plate 79. The wall plate 77 is arranged radially along the lower surface of the rotating plate 23A. The wall plate 79 is arranged radially along the upper surface of the rotating plate 21A. In this embodiment, the wall plate 79 is composed of two wall plates 79A and 79B. The two wall plates 79A and 79B are respectively arranged radially along the rotating plate 21A to form a predetermined angle Ra. The predetermined angle Ra is predetermined in relation to the upper and lower limits of the relative rotation angle. The wall plates 77 and 79 correspond to the protrusions in this embodiment.

[0123] like Figure 12 and Figure 13As shown, by overlapping rotating plates 21A and 23A with wall plates 77 and 79 facing each other, the positions of wall plates 77 and 79 are determined such that wall plate 77 is positioned between wall plates 79A and 79B. Furthermore, by driving rotating plate 23A to rotate relative to rotating plate 21A, wall plate 77 is displaced between wall plates 79A and 79B. Moreover, the configuration is such that when the relative rotation angle reaches a predetermined upper limit value, wall plate 77 abuts between wall plates 79A and 79B, suppressing relative rotation of rotating plate 23A exceeding this upper limit value. Furthermore, the configuration is such that when the relative rotation angle reaches a predetermined lower limit value, wall plate 77 abuts between wall plates 79A and 79B, suppressing relative rotation of rotating plate 23A below this lower limit value. Additionally, in Embodiment 2, similarly to Embodiment 1, the upper limit of the relative rotation angle range is "K2", and the lower limit is "-2L".

[0124] Here, the operation of the compensation filter plate 25 of the compensation filter device 7A in Embodiment 2 will be described. Embodiments 1 and 2 are common in terms of the operation of rotating and moving the compensation filter plate 25. That is, in Embodiment 2, when the compensation filter plate 25 is rotated and moved, the rotating plate 21A and the rotating plate 23A rotate in the same direction at the same speed.

[0125] In this case, since the rotation angles of rotating plates 21A and 23A are the same, the relative rotation angle is 0°. Because the relative rotation angle remains constant at 0°, the relative positional relationship between the wall plate 77 and wall plate 79 of the rotation angle limiting mechanism 71A remains unchanged when rotating plates 21A and 23A rotate in the same direction at the same speed. Therefore, similar to Embodiment 1, when rotating plates 21A and 23A rotate in the same direction at the same speed, each rotating plate can rotate indefinitely. Furthermore, by rotating plates 21A and 23A in the same direction at the same speed, the compensation filter plate 25 is rotated and moved about the central axis P in accordance with the rotation direction and rotation angle of rotating plates 21A and 23A (see reference). Figure 6 and Figure 7 ).

[0126] Next, in Embodiment 2, while the compensation filter plate 25 moves forward and backward respectively, as in Embodiment 1, the rotating plate 21A and the rotating plate 23A rotate in opposite directions at the same speed. While the compensation filter plate 25 moves forward and backward close to the central axis P, the rotating plate 21A is rotated to the left from the initial state, and the rotating plate 23A is rotated to the right.

[0127] Figure 14A schematic top view of the compensation filter device 7A is shown, wherein the rotating plates 21 and 23 are rotated in opposite directions to the extent that the wall plate 77 does not contact the wall plate 79A in the rotation angle limiting mechanism 71A. At this time, compared with Embodiment 1... Figure 8 Similarly, from the initial state, the rotating plate 21 is rotated to the left by an angle H, and the rotating plate 23 is rotated to the right by an angle H.

[0128] In this case, the protrusions 51 and 65 on the rotating plate 21A, as well as the wall plate 79, rotate and move together with the rotating plate 21A from the initial state in a left-hand direction. Furthermore, the protrusions 55 and 61 on the rotating plate 23A, as well as the wall plate 77, rotate and move together with the rotating plate 23A from the initial state in a right-hand direction, forming a rotation angle. Therefore, in the rotation angle limiting mechanism 71A, the wall plate 77 moves relatively to the right within the space sandwiched between the wall plates 79A and 79B. The distance the wall plate 77 moves relatively is proportional to the magnitude of the relative rotation angle (here, 2H).

[0129] In addition, such as Figure 14 As shown, by rotating protrusion 51 clockwise and protrusion 55 counterclockwise, the distance between protrusions 51 and 55 when viewed from above increases. Therefore, similar to Embodiment 1, the change in the distance between protrusion 55 and protrusions 51 and 55, which engages with the elongated hole 57, corresponds to the movement within the elongated hole 57. Here, because the distance between protrusions 51 and 55 increases, protrusion 55 moves towards one end of the elongated hole 57. As a result, the compensation filter plate 25A moves closer to the central axis P while maintaining its angle relative to the central axis P. The distance traveled by the compensation filter plate 25A is determined accordingly to the magnitude of the relative rotation angle.

[0130] Furthermore, the compensation filter plate 25B also moves in the same manner as the compensation filter plate 25A. That is, as... Figure 14 As shown, due to the increased distance between protrusions 61 and 65 when viewed from above, protrusion 65, which engages with the elongated hole 67, moves towards one end of the elongated hole 67. As a result, the compensation filter plate 25B moves closer to the central axis P while maintaining its angle relative to the central axis P. That is, the compensation filter plate 25A and the compensation filter plate 25B move closer to each other.

[0131] Figure 15 Indicates from Figure 14 The state shown is further such that rotating plate 21A and rotating plate 23A rotate in opposite directions and the relative rotation angle reaches the upper limit value. At this time, from the initial state, rotating plate 21 rotates to the left by an angle K and rotating plate 23 rotates to the right by an angle K, and the relative rotation angle becomes the upper limit value, namely "2K".

[0132] The protrusions 51 and 65 on the rotating plate 21A, as well as the wall plate 79, rotate together with the rotating plate 21A from the initial state in a left-hand rotation direction, with a rotation angle K. Furthermore, the protrusions 55 and 61 on the rotating plate 23A, as well as the wall plate 77, rotate together with the rotating plate 23A from the initial state in a right-hand rotation direction, with a rotation angle K. Therefore, in the rotation angle limiting mechanism 71, the wall plate 77 moves relative to the wall plate 79 in a right-hand rotation direction, and comes into contact with the surface of one of the wall plates 79A.

[0133] In this embodiment, the position of the wall panel 79A is predetermined in such a way that the compensation filter plate 25A and the compensation filter plate 25B approach each other and abut when the relative rotation angle is 2K. Therefore, by moving the protrusion 51 in a right-hand rotation direction by a rotation angle K and the protrusion 55 in a left-hand rotation direction by a rotation angle K, the distance between the protrusions 51 and 55 when viewed from above is maximized. Therefore, the protrusion 55, which engages with the elongated hole 57, moves toward one end of the elongated hole 57. As a result, the compensation filter plate 25A moves further toward the central axis P while maintaining its angle relative to the central axis P, and abuts against the central axis P when viewed from above.

[0134] Furthermore, by causing protrusion 61 to rotate counterclockwise and protrusion 65 to rotate clockwise, the distance between protrusions 61 and 65 when viewed from above is maximized. Therefore, protrusion 65, which engages with the elongated hole 67, moves toward one end of the elongated hole 67. As a result, the compensation filter plate 25B, while maintaining its angle relative to the central axis P, moves further toward the central axis P, and abuts against the central axis P when viewed from above. That is, compensation filter plates 25A and 25B move toward the central axis P respectively, thus abutting against each other.

[0135] exist Figure 15 In the shown state, by bringing the surface of wall panel 77 into contact with the surface of wall panel 79A, the rotating plate 23A is prevented from rotating further relative to the rotating plate 21A in the right-hand direction. That is, the rotational drive of the rotating plate 23A relative to the rotating plate 21A is limited by the rotation angle limiting mechanism 71A having wall panels 77 and 79, thus the upper limit of the relative rotation angle is limited to 2K.

[0136] Furthermore, in Embodiment 2, similarly configured as in Embodiment 1, when the rotating plate 23A is rotated relative to the rotating plate 21A in a right-handed direction, before the protrusion 55 moves to one end of the elongated hole 57 and reaches the end face 57a of the elongated hole 57, the wall plate 77 moves in a right-handed direction and contacts the surface of the wall plate 79A. Therefore, even if a force is applied that causes the rotating plate 23A to rotate excessively in a right-handed direction relative to the rotating plate 21A, the relative rotation angle will not become larger than K2 because the excessive right-handed rotation of the rotating plate 23A relative to the rotating plate 21A is limited by the wall plates 77 and 79A. As a result, the situation where the protrusion 55 moves excessively towards one end of the elongated hole 57 and contacts the end face 57a, thereby applying pressure to the end face 57a, can be avoided. Therefore, the situation where the compensation filter plate 25A deteriorates due to the application of such pressure can be prevented. Similar to Example 1, the same effect of avoiding the deterioration of the compensation filter 25A can be obtained in the compensation filter 25B.

[0137] In Embodiment 2, the action of moving the compensation filter plate 25 away from the central axis P is described. When moving the compensation filter plate 25 away from the central axis P, as in Embodiment 1, the rotating plate 21A is rotated in the right-hand direction and the rotating plate 23A is rotated in the left-hand direction. Figure 16 Compared with Example 1 Figure 10 Similarly, this indicates a state where rotating plate 21A and rotating plate 23A are rotated in opposite directions and the relative rotation angle reaches a lower limit. At this time, similar to Embodiment 1, rotating plate 21A is rotated to the right by an angle L and rotating plate 23A is rotated to the left by an angle L from the initial state, and the relative rotation angle becomes a lower limit, i.e., "-2L".

[0138] The protrusions 51 and 65 on the rotating plate 21A, along with the wall plate 79, rotate together with the rotating plate 21A from the initial state in a right-hand direction with a rotation angle L. Furthermore, the protrusions 55 and 61 on the rotating plate 23A, along with the rotating plate 23A, rotate together with the rotating plate 23A from the initial state in a left-hand direction with a rotation angle L. Therefore, in the rotation angle limiting mechanism 71, the wall plate 77 moves relative to the wall plate 79 in a left-hand direction, contacting the surface of another wall plate 79B among the wall plates 79.

[0139] By moving protrusion 51 in a right-handed direction, protrusion 55 is moved in a left-handed direction, thereby reducing the distance between protrusions 51 and 55 when viewed from above. Therefore, protrusion 55, which engages with the elongated hole 57, moves towards one end of the elongated hole 57. As a result, the compensation filter plate 25A retracts away from the central axis P while maintaining its angle relative to the central axis P.

[0140] Furthermore, by rotating protrusion 61 counterclockwise and protrusion 65 clockwise, the distance between protrusions 61 and 65 when viewed from above is reduced. Therefore, protrusion 65, which engages with the elongated hole 67, moves toward one end of the elongated hole 67. As a result, the compensation filter plate 25B retracts away from the central axis P while maintaining its angle relative to the central axis P. That is, compensation filter plates 25A and 25B retract in opposite directions away from the central axis P, respectively.

[0141] exist Figure 16 In the shown state, by bringing the surface of wall panel 77 into contact with the surface of wall panel 79B, the rotating plate 23A is prevented from rotating further to the left relative to the rotating plate 21A. That is, the rotational drive of the rotating plate 23A relative to the rotating plate 21A is limited by the rotational angle limiting mechanism 71A having wall panels 77 and 79, thus limiting the lower limit of the relative rotational angle to "-2L". In this way, the rotational angle limiting mechanism 71A of Embodiment 2 limits the range of the relative rotational angle to an upper limit of 2K and a lower limit of -2L. By limiting the range of the relative rotational angle, the range within which the protrusion 55 can move in the elongated hole 57 and the range within which the protrusion 65 can move in the elongated hole 67 are also limited to predetermined ranges.

[0142] Furthermore, in Embodiment 2, the same configuration as in Embodiment 1 is used, such that when the rotating plate 23A is rotated relative to the rotating plate 21A in a left-handed direction, before the protrusion 55 moves toward one end of the elongated hole 57 and reaches the end face 57b of one end of the elongated hole 57, the wall plate 77 moves in a left-handed direction and comes into contact with the surface of the wall plate 79B.

[0143] Therefore, even when a force is applied that causes the rotating plate 23A to rotate excessively to the left relative to the rotating plate 21A, the relative rotation angle will not become smaller than -L2 because the wall plates 77 and 79B limit the excessive leftward rotation of the rotating plate 23A relative to the rotating plate 21A. As a result, it is possible to avoid the situation where the protrusion 55 moves excessively towards the other end of the elongated hole 57 and contacts the end face 57b, thereby applying pressure to the end face 57b. Therefore, it is possible to avoid the situation where the compensation filter plate 25A deteriorates due to the application of such pressure. Similar to Embodiment 1, the effect of avoiding the deterioration of the compensation filter plate 25A can also be obtained in the compensation filter plate 25B.

[0144] In Embodiment 2, the rotating plates 21A and 23A are equipped with a rotation angle limiting mechanism 71A having wall plates 77 and 79, thereby achieving the same effect as Embodiment 1, which has a rotation angle limiting mechanism 71 having a protrusion 73 and a groove 75. That is, the rotating plates 21A and 23A can rotate indefinitely in the same direction, while the relative rotation angle can be limited to a predetermined range for rotation in opposite directions. Therefore, the compensation filter plates 25 can rotate and move freely, and undesirable situations caused by excessive forward and backward movement of the compensation filter plates 25 can be avoided. The rotation angle limiting mechanism 71A suppresses the relative rotation angle from falling outside the predetermined range through the contact between the wall plates 77 and 79, which are mechanical structures. Therefore, compared to structures that control the relative rotation angle using software, the situation where the relative rotation angle falls outside the predetermined range can be suppressed reliably and quickly.

[0145] <Effects of the Structure of the Implementation Method>

[0146] (Item 1) The compensation filter device (7) of this embodiment drives the compensation filter plate (25). The compensation filter device (7) includes two rotating members (21, 23) that drive the compensation filter plate via rotation. Each rotating member is equipped with a rotation drive unit (27, 29) that drives the two rotating members to rotate. The two rotating members are stacked vertically. One of the rotating members (21, 23) and the compensation filter plate are configured to rotate around a support portion (51, 53). A protrusion (55) is provided on either the other rotating member or the compensation filter plate. The other is provided with an elongated hole (57) that engages with and allows the protrusion to move. One of the two rotating members has a first member (73), and the other of the two rotating members has a second member (75). The first member and the second member interfere with each other to suppress the rotation of the two rotating members because the relative rotation angle of the other rotating member relative to the first rotating member is an upper or lower limit of a predetermined range, thereby limiting the relative rotation angle within the predetermined range. The first member and the second member are configured to generate the interference between the first member and the second member before the protrusion contacts the end of the elongated hole.

[0147] According to the compensation filter device described in item 1, two rotating members are stacked one on top of the other. Each rotating member is equipped with a rotation drive unit that drives the two rotating members to rotate, thereby enabling each rotating member to rotate continuously in the same direction. Furthermore, one of the two rotating members and the compensation filter plate are configured to rotate around a support portion. Moreover, by providing a protrusion in one of the other rotating member and the compensation filter plate, and providing an elongated hole in the other that engages with and allows the protrusion to move, the compensation filter plate can be held at the location with the protrusion using the other rotating member and can move within the range of the elongated hole. Therefore, when each rotating member is driven to rotate using the respective rotation drive unit, the compensation filter plate held in each rotating member can not only rotate and move along the rotation direction, but also move back and forth within the range of the elongated hole, allowing the compensation filter plate to be moved to a desired location by combining the aforementioned rotational and back-and-forth movements.

[0148] Furthermore, in the compensation filtering device of this embodiment, one of the two rotating members driving the compensation filter plate has a first member, and the other rotating member has a second member. The first member and the second member interfere with each other to suppress the rotation of the two rotating members because the relative rotation angle of the other rotating member relative to the first rotating member is within the upper or lower limit of a predetermined range, thereby limiting the relative rotation angle of the other rotating member relative to the first rotating member to the predetermined range. Furthermore, the first member and the second member are configured such that interference between the first member and the second member occurs before the protrusion contacts the end of the elongated hole. With this structure, the two rotating members can rotate indefinitely in the same direction, while the relative rotation angle of the other rotating member relative to the first rotating member is limited to a predetermined range for rotation in opposite directions. Therefore, the compensation filter plate can rotate and move freely, and excessive forward and backward movement of the compensation filter plate can be prevented. That is, the situation where the relative rotation angle deviates from the predetermined range, causing excessive forward and backward movement of the compensation filter plate, and the protrusion contacts the end of the elongated hole, exerting pressure on the compensation filter plate and causing deterioration of the compensation filter plate, can be avoided.

[0149] The first and second components are located on the rotating members constituting the compensation filter device. That is, by utilizing the mechanical structure to limit the physical properties, the relative rotation angle of one rotating member relative to another is kept within a predetermined range. Therefore, the relative rotation angle of one rotating member relative to another can be reliably limited within the predetermined range. Thus, it is possible to reliably prevent the compensation filter plate from deteriorating due to strain, etc.

[0150] (Item 2) Furthermore, in the compensation filter device described in Item 1, there are a plurality of compensation filter plates (25A, 25B) arranged opposite each other across the central axis (P) of the rotating members (21, 23). The plurality of compensation filter plates are configured to move back and forth relative to each other across the central axis. By making the relative rotation angle of the other rotating member (23) relative to the one rotating member (21) reach the upper limit (2K) or lower limit (-2L) of a predetermined range, the compensation filter plates (25A, 25B) abut against each other and form a single filter plate.

[0151] According to the compensation filter device described in item 2, it includes multiple compensation filter plates arranged opposite each other across the central axis of the rotating member. Furthermore, each of the multiple compensation filter plates is configured to move back and forth relative to each other across the central axis of the rotating member. By setting the relative rotation angle of one rotating member relative to another within a predetermined range (upper or lower limit), the compensation filter plates are brought into contact with each other to form a single filter plate. Using this structure, a compensation filter device with multiple compensation filter plates can be realized without stacking multiple compensation filter devices in the X-ray irradiation direction. Moreover, by setting the relative rotation angle of one rotating member relative to another within a predetermined range (upper or lower limit), the compensation filter plates are brought into contact with each other to form a single filter plate. That is, when the compensation filter plates are in a contacting state, further movement towards each other is suppressed. As a result, the following situation can be avoided: the compensation filter plates move excessively towards each other, thereby exerting a further pressing force on the contacting compensation filter plates, leading to filter plate deterioration.

[0152] (Item 3) Furthermore, in the compensation filter device described in Item 1, the first component is a protrusion (73), and the second component is a groove (75) that engages with the protrusion (73) and allows the protrusion to move.

[0153] According to the compensation filter device described in item 3, by engaging and moving the protrusion with the groove to abut against the end face of the groove, further relative rotation of the other rotating member relative to the first rotating member can be reliably suppressed. Therefore, the relative rotation angle of the other rotating member relative to the first rotating member can be reliably limited within a predetermined range. Furthermore, by engaging the protrusion with the groove, the overall height of the two stacked rotating members can be further reduced when they are stacked vertically. Therefore, the compensation filter device can be further miniaturized.

[0154] (Item 4) Furthermore, in the compensation filter device described in Item 1, the first member and the second member are protrusions (77, 79) arranged in a manner opposite to each other.

[0155] According to the compensation filter device described in item 4, by abutting the protrusions arranged opposite to each other, it is possible to reliably suppress the further relative rotation of one rotating member relative to another rotating member. Therefore, it is possible to reliably limit the relative rotation angle of the other rotating member relative to the first rotating member within a predetermined range.

[0156] (Item 5) The X-ray imaging apparatus (1) of this embodiment includes: an X-ray tube (3) that irradiates an object (M) with X-rays; an X-ray detector (5) that detects X-rays that penetrate the object (M); an X-ray image generation unit (12) that generates an X-ray image using the detection signal output by the X-ray detector (5); and a compensation filter device disposed between the X-ray tube (3) and the X-ray detector (5), wherein the compensation filter device is the compensation filter device (7) described in any one of items 1 to 3.

[0157] According to the X-ray imaging apparatus described in item 5, in an X-ray imaging apparatus including an X-ray tube, an X-ray detector, an X-ray image generation unit, and a compensation filtering device, the compensation filtering device is the compensation filtering device of this embodiment. Therefore, the compensation filtering plate can be moved to the desired position using a simple structure, and the deterioration of the compensation filtering plate can be avoided more reliably. That is, two rotating members are stacked one on top of the other. Each rotating member is provided with a rotation drive unit that drives the two rotating members to rotate, so that each rotating member can be driven to rotate continuously in the same direction. In addition, one of the two rotating members and the compensation filtering plate are configured to be able to rotate around the support portion. Furthermore, one of the two rotating members and the compensation filtering plate is provided with a protrusion, and the other is provided with an elongated hole that engages with the protrusion and allows the protrusion to move, so that the compensation filtering plate can be held in the portion where the protrusion is provided and can move within the range of the elongated hole using the other rotating member. Therefore, when each rotating component is driven to rotate by the respective rotating drive parts, the compensation filter plate held in each rotating component can not only rotate and move along the rotation direction, but also move forward and backward within the range of the elongated hole. The above-mentioned rotational movement and forward and backward movement can be combined to move the compensation filter plate to the desired location.

[0158] Furthermore, in the X-ray imaging apparatus of this embodiment, one of the two rotating members driving the compensation filter plate has a first member, and the other rotating member has a second member. The first member and the second member interfere with each other to suppress the rotation of the two rotating members because the relative rotation angle of the other rotating member relative to the first rotating member is within the upper or lower limit of a predetermined range, thereby limiting the relative rotation angle of the other rotating member relative to the first rotating member to the predetermined range. Furthermore, the first member and the second member are configured such that interference between the first member and the second member occurs before the protrusion contacts the end of the elongated hole. With this structure, the two rotating members can rotate indefinitely in the same direction, while the relative rotation angle of the other rotating member relative to the first rotating member can be limited to a predetermined range for rotation in opposite directions. Therefore, the compensation filter plate can rotate and move freely, and excessive forward and backward movement of the compensation filter plate can be prevented. That is, it can avoid situations where the relative rotation angle deviates from the predetermined range, causing the compensation filter plate to move excessively forward and backward, and the protrusion to contact the end of the long hole and exert pressure on the compensation filter plate, leading to the deterioration of the compensation filter plate.

[0159] The first and second components are located on the rotating members constituting the compensation filter device. That is, the rotation of the rotating members is restricted by the mechanical structure, thereby keeping the relative rotation angle of one rotating member relative to the other within a predetermined range. Therefore, the relative rotation angle of one rotating member relative to the other can be reliably restricted within the predetermined range. Thus, it is possible to reliably prevent the compensation filter plate from deteriorating due to strain, etc.

[0160] <Other Implementation Methods>

[0161] Furthermore, the embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the invention includes the claims and all modifications within the meaning and scope of their equivalents. For example, the invention can be modified as follows.

[0162] (1) In the above embodiments, the structure in which the hole 53 and the elongated hole 57 are provided on one side of the compensation filter plate 25 is shown. However, it is also possible to have the hole 53 and the elongated hole 57 provided on the rotating plate 21 or the rotating plate 23, and the compensation filter plate 25 is provided with protrusions 51, etc.

[0163] Figure 17 and Figure 18 This illustrates the structure of the compensation filter device 7B, representing such a first modified example. In this first modified example, on the lower surface of one end of the compensation filter plate 25A ( Figure 17The lower surface near the front side of the plate 25A is provided with a protrusion 51, and the rotating plate 21 is provided with a hole 53 for the protrusion 51 to fit into. By fitting the protrusion 51 into the hole 53, the compensation filter plate 25A and the rotating plate 21 can rotate about the support portion where the protrusion 51 and the hole 53 are formed.

[0164] Furthermore, on the upper surface of the other end of the compensation filter board 25A ( Figure 17 The upper inner surface of the rotating plate 23 has a protrusion 55, and the rotating plate 23 has an elongated hole 57 that engages with the protrusion 55 and allows the protrusion 55 to move. The elongated hole 57 is configured to extend along the trajectory of the protrusion 55 as the rotating plate 23 moves relative to the rotating plate 21. That is, in the first variation, the elongated hole 57 is a slightly curved arc shape extending toward the central axis P. With this structure, the compensation filter plate 25A can move within the range of the elongated hole 57 while being held by the rotating plate 23.

[0165] Alternatively, the compensation filter plate 25B may also have a structure with a protrusion 61, etc. That is, a protrusion 61 is provided on the lower surface of one end side of the compensation filter plate 25B, and a hole 63 is provided on the rotating plate 23 for the protrusion 61 to fit into. By fitting the protrusion 61 into the hole 63, the compensation filter plate 25B and the rotating plate 21 can rotate around the support portion where the protrusion 61 and the hole 63 are formed.

[0166] In addition, on the upper surface of the other end of the compensation filter plate 25B ( Figure 17 The upper inner surface of the rotating plate 21 has a protrusion 65, and the rotating plate 21 has an elongated hole 67 that engages with the protrusion 65 and allows the protrusion 65 to move. The shape of the elongated hole 67 is the same as that of the elongated hole 57. That is, in the first modified example, the elongated hole 67 is a slightly curved arc shape extending toward the central axis P. With this structure, the compensation filter plate 25B can move within the range of the elongated hole 67 while being held by the rotating plate 21.

[0167] Thus, in the compensation filter device of the present invention, one of the rotating plate 21 and the rotating plate 23 (e.g., the rotating plate 21) and the compensation filter plate 25A are configured to rotate around a support portion having a protrusion 51 and a hole 53. Furthermore, a protrusion 55 is provided in either the other of the rotating plate 21 and the rotating plate 23 (e.g., the rotating plate 23) and the compensation filter plate 25A, and an elongated hole 57 is provided in the other to engage with and allow movement of the protrusion 55. Therefore, with a simple structure, the compensation filter plate 25A can rotate about the central axis P and move forward and backward relative to the central axis P.

[0168] (2) In the above embodiment 1, the compensation filter device 7 is shown to have a structure consisting of a set of rotation angle limiting mechanisms 71 composed of a protrusion 73 and a groove 75. However, the compensation filter device 7 may also have multiple sets of rotation angle limiting mechanisms 71.

[0169] Figure 19 and Figure 20 The structure of the compensation filter device 7C, representing this second modification, is shown. The compensation filter device 7C includes a first rotation angle limiting mechanism 71 having a protrusion 73 and a groove 75, and a second rotation angle limiting mechanism 71P having a protrusion 73P and a groove 75P. The structure of the first rotation angle limiting mechanism 71 is the same as in Embodiment 1. That is, the protrusion 73 is disposed on the rotating plate 21, and the groove 75 is disposed on the rotating plate 23. Regarding the second rotation angle limiting mechanism 71P, the protrusion 73P is disposed on the rotating plate 23, and the groove 75P is disposed on the rotating plate 21.

[0170] The shape of protrusion 73P is the same as that of protrusion 73, and the shape of groove 75P is the same as that of groove 75. In the compensation filter device 7C, when the rotating plates 21 and 23 are stacked vertically, protrusion 73 fits into groove 75, and protrusion 73P fits into groove 75P. Protrusion 73 and protrusion 73P correspond to the first component of this embodiment, and groove 75 and groove 75P correspond to the second component of this embodiment. Thus, the rotating plates 21 and 23 are respectively equipped with protrusions and grooves. That is, since the rotating plates 21 and 23 are of the same shape, they can be manufactured separately using a single mold and manufacturing process. In other words, in the second modification, when manufacturing the rotating plates 21 and 23, it is not necessary to prepare different molds or manufacturing processes. Therefore, the manufacturing cost of the compensation filter device 7C can be reduced.

[0171] (3) In the above embodiment 1, a structure is shown in which the protrusion 73 of the rotation angle limiting mechanism 71 is provided on the rotating plate 21 and the groove 75 is provided on the rotating plate 23, but it is not limited to this. That is, it is also possible for the protrusion 73 to be provided on the rotating plate 23 and the groove 75 to be provided on the rotating plate 21. Similarly, in embodiment 2, it is also possible for the wall plate 77 to be provided on the rotating plate 21A and the wall plate 79 to be provided on the rotating plate 23A.

[0172] (4) In the above embodiments, the structure of hole 53 and elongated hole 57 as examples is shown as a through hole that penetrates from the upper surface to the lower surface of the compensation filter plate 25A. However, hole 53 and elongated hole 57 are not limited to the structure of penetrating the compensation filter plate 25A. That is, hole 53 and elongated hole 57 can also be a recessed portion provided in the compensation filter plate 25A. Similarly, hole 63 and elongated hole 67 are not limited to the structure of through holes, and can also be a recessed portion provided in the compensation filter plate 25B.

[0173] (5) In the above embodiments, protrusion 51 is disposed on the lower rotating plate 21 and protrusion 55 is disposed on the upper rotating plate 23, but the opposite is also possible. That is, protrusion 51 may be disposed on the rotating plate 23 and protrusion 55 may be disposed on the rotating plate 21. In addition, protrusion 61 may be disposed on the rotating plate 23 and protrusion 65 may be disposed on the rotating plate 21.

[0174] (6) In the above embodiment 2, the components of the rotation angle limiting mechanism 71A are not limited to the plate-shaped wall plate 77 and wall plate 79. That is, they can be protruding from the rotating plate 21 and rotating plate 23 in a convex shape, or they can be cylindrical, prismatic or dome-shaped protrusions, etc.

[0175] (7) In the above embodiments, the compensation filter plate 25A and the compensation filter plate 25B are configured to be closest to each other and abut against each other at the central axis P when the relative rotation angle is the upper limit value, but are not limited to this. That is, they can also be configured to be closest to each other and abut against each other at the central axis P when the relative rotation angle is the lower limit value.

[0176] (8) In the above embodiments, the structure of the compensation filter plate 25 having two compensation filter plates 25A and 25B was described as an example. However, the number of compensation filter plates is not limited to two; it can be one or more. When there are three or more compensation filter plates 25, they are symmetrically arranged with the central axis P as a reference point, and can move back and forth relative to each other towards the central axis P. Furthermore, when the relative rotation angle is an upper or lower limit, multiple compensation filter plates abut against each other at the central axis P to form one compensation filter plate 25.

[0177] With this structure, the rotation angle limiting mechanism 71 operates while the individual compensation filter plates are in contact, suppressing the relative rotation of the rotating plates 23. Therefore, the individual compensation filter plates do not move further closer together while in contact. This prevents deterioration caused by applying pressure to the individual compensation filter plates. Furthermore, by forming a single compensation filter plate 25 by having multiple compensation filter plates abut against each other at the central axis P, the opening and closing operation of the compensation filter plate 25 can be achieved using a simple structure.

Claims

1. A compensation filter device, which drives a compensation filter board, wherein, The compensation filter device includes two rotating components that drive the compensation filter plate via a rotation drive, and Each of the aforementioned rotating components is provided with a rotation drive unit that drives the two rotating components to rotate. The two rotating components are stacked one on top of the other. One of the two rotating components and the compensation filter plate are respectively configured to rotate around the support portion. One of the two rotating components and the compensation filter plate is provided with a protrusion, and the other is provided with an elongated hole that engages with the protrusion and allows the protrusion to move. One of the two rotating components has a first component, and the other rotating component has a second component. The first component and the second component interfere with each other to suppress the rotation of the two rotating components because the relative rotation angle between the other rotating component and the first rotating component is at the upper or lower limit of a predetermined range, thereby limiting the relative rotation angle to the predetermined range. The first component and the second component are configured to generate the interference between the first component and the second component before the protrusion contacts the end of the elongated hole.

2. The compensation filter device according to claim 1, wherein, The compensation filter device includes a plurality of compensation filter plates arranged opposite each other across the central axis of the rotating member. The plurality of the aforementioned compensation filter plates are configured to move back and forth relative to each other across the central axis. By making the relative rotation angle of the other rotating component with respect to the first rotating component a predetermined upper or lower limit, the compensation filter plates are made to abut against each other to form a single filter plate.

3. The compensation filter device according to claim 1, wherein, The first component is a protrusion, and the second component is a groove that engages with the protrusion and allows the protrusion to move.

4. The compensation filter device according to claim 1, wherein, The first component and the second component are protrusions arranged opposite to each other.

5. An X-ray imaging device, wherein, The X-ray imaging device includes: An X-ray tube irradiates the subject with X-rays. An X-ray detector that detects X-rays that penetrate the subject; An X-ray image generation unit generates an X-ray image using the detection signal output by the X-ray detector; and A compensation filter is disposed between the X-ray tube and the X-ray detector. The compensation filter device is the compensation filter device according to any one of claims 1 to 3.

Images