Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
  • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
  • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
  • G01N23/046—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using tomography, e.g. computed tomography [CT]
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2223/00—Investigating materials by wave or particle radiation
  • G01N2223/40—Imaging
  • G01N2223/419—Imaging computed tomograph

Definitions

• the present invention relates to an industrial X-ray CT apparatus and an X-ray CT for obtaining a tomographic image of non-destructive investigation of internal defects and internal structures of industrial products such as electronic parts. About the method.
• a rotating stage that rotates around an axis orthogonal to the X-ray optical axis is generally arranged between an X-ray source and an X-ray detector that are arranged opposite to each other. Then, while irradiating X-rays with the subject held on the rotating stage, X-ray transmission data of the X-ray detector force is captured each time the rotating stage is rotated by a predetermined minute angle. Then, using the acquired X-ray transmission data, a tomographic image of a subject along a plane perpendicular to the rotation axis of the rotary stage is reconstructed (see, for example, Patent Document 1).
• the rotation stage is normally movable in the direction of the X-ray optical axis (X-axis direction) and the direction orthogonal to it (y and z-axis directions) by a moving mechanism.
• X-axis direction the direction of the X-ray optical axis
• y and z-axis directions the direction orthogonal to it
• xy table for moving a subject in two axial directions (X and y axis directions) perpendicular to the rotation axis.
• Patent Document 1 Japanese Patent Publication No. 2004-117024
• an xy table is provided on the rotary stage so that a desired position on the subject can be moved to the vicinity of the rotation center. It is necessary to carry out the above adjustment work again after the operation to see if it interferes with the X-ray source, which causes a reduction in work efficiency.
• the present invention has been made to solve various problems in the conventional industrial X-ray CT apparatus, and the main problem is that it can prevent interference with the X-ray source when the subject rotates, and CT imaging.
• the object is to provide an X-ray CT apparatus and an X-ray CT method that can eliminate the need for the operator to perform confirmation work by rotating the rotary stage before.
• Still another object of the present invention is to intuitively grasp the power or inability to obtain an intended tomographic image. It is to provide an X-ray CT apparatus capable of performing the above.
• the X-ray CT apparatus of the present invention holds an object between an X-ray source and an X-ray detector arranged to face each other and is orthogonal to the X-ray optical axis.
• a rotating stage that rotates around the rotating axis is disposed, and a plane orthogonal to the rotating axis is obtained by using the X-ray transmission data of the subject captured at predetermined angles while rotating the rotating stage.
• the X-ray CT apparatus having a reconstruction calculation unit that reconstructs a tomographic image of the subject along the line, and the subject on the rotation stage is positioned on or near the rotation axis of the rotation stage.
• An optical camera that captures the image, an image processing unit that obtains information on the shape, size, and position of the subject relative to the rotation axis from the appearance image of the subject captured by the optical camera, and the image processing unit. It is characterized by having an interference monitoring unit that monitors the interference between the subject and the X-ray source when the rotary stage is rotated using the obtained information.
• the specific configuration of the interference monitoring unit according to the present invention is based on the position of the X-ray source and the rotary stage, and the information obtained by the image processing unit. It is determined whether or not the subject and the X-ray source interfere with each other during rotation, and if there is an interference, a warning is given to that effect, or in the same manner, the subject and the X when the rotation stage is rotated. It is possible to adopt a configuration in which it is determined whether or not the force interferes with the radiation source, and in the case of interference, the rotation of the rotary stage is prohibited.
• the interference monitoring unit determines the rotation direction of the rotary stage without causing the subject to interfere with the X-ray source. It is also possible to adopt a configuration in which interference monitoring is performed by restricting the rotary stage so that it can approach the X-ray source more closely.
• the rotation axis of the rotary stage is closest to the X-ray source, and A configuration including a rotary stage position setting unit that sets the position of the rotary stage at which the subject does not interfere with the X-ray source when the rotary stage rotates can also be adopted.
• the rotary stage position setting unit sets the rotation direction of the rotary stage, and the subject is the X It is possible to adopt a configuration that sets the position of the rotary stage by restricting the rotary stage so that it can approach the X-ray source without interfering with the X-ray source. When the half scan is selected, the operator does not need to consider the direction of rotation of the subject, and other problems of the present invention can be solved.
• the positional relationship of the X-ray source, the X-ray detector, and the rotation stage in the X-ray optical axis direction and the size of the light receiving surface of the X-ray detector Using this information, a CT imaging area calculation unit that calculates a CT-capable area centered on the rotation axis and the area calculated by the CT imaging area calculation unit were imaged by the optical camera. It is preferable to employ a configuration including a display unit that superimposes on a subject image and displays the image on a display.
• the positional relationship of the X-ray source, the X-ray detector, and the rotary stage in the X-ray optical axis direction and the size of the light receiving surface of the X-ray detector are determined.
• a CT imaging region calculation unit that calculates a CT imageable region centered on the rotation axis, and a subject imaged by the optical camera using the CT imaging region calculation unit.
• the X-ray detector or the object is linked to the X-ray optical axis in conjunction with a display unit that is superimposed on the image and displayed on the display unit, and the size of the region displayed on the display unit is changed. It is preferable to adopt a configuration with a control unit that moves in the direction.
• the X-ray CT apparatus of the present invention is an invention in which main constituent elements are the same as those of the X-ray CT apparatus, and an object between an X-ray source and an X-ray detector arranged to face each other.
• a rotation stage that rotates around a rotation axis that is orthogonal to the X-ray optical axis is arranged, and the X-ray transmission data of the subject captured at a predetermined angle while rotating the rotation stage is used.
• the subject on the rotation stage is placed on the rotation stage.
• Positional force on or near the rotation axis Take an image from the optical camera and the appearance image of the subject taken by the optical camera.
• An image processing unit that obtains information related to the shape, size, and position of the rotation axis, and information obtained by the image processing unit is used to detect the subject in the field of view of the X-ray detector during X-ray air calibration. It is characterized by having a subject retracting section that moves it outside.
• a subject on a rotary stage is photographed with an optical camera on or near its rotational axis, and the image power of the subject is information relating to the shape, size, and position of the subject relative to the rotational axis.
• the image power of the subject is information relating to the shape, size, and position of the subject relative to the rotational axis.
• the shape and size of the subject and position information with respect to the rotation axis of the rotation stage are obtained. Can do. From this information, it is possible to determine whether or not the force interferes with the X-ray source when the subject is rotated at the current rotation stage position (rotation axis position). In the above X-ray CT system, an alarm is issued when it is determined that interference occurs, or the rotation of the rotary stage is prohibited.
• the rotation axis of the rotary stage is closest to the X-ray source, and the position where the subject does not interfere with the X-ray source, that is, the imaging magnification and brightness are the same. Position automatically at the maximum position.
• Such monitoring or positioning operation eliminates the need for confirmation work and repositioning work for the presence of interference prior to CT imaging.
• the orientation of the subject can be determined from the appearance image of the subject on the rotary stage without interfering with the X-ray source. Limit the direction of rotation to that direction, and then monitor or position the rotation stage.
• the operator's work prior to C ⁇ imaging can be greatly reduced.
• it is possible to quickly determine whether or not a tomographic image covering an intended region can be obtained with the function of the interference monitoring unit or setting unit described above in a state where the rotary stage is as close as possible to the X-ray source. Therefore, when it is not possible to cover, it is possible to use the rotating stage with the X-ray source force away from the closest approach point.
• the X-ray CT apparatus can geometrically form a CT-capable region.
• the calculated area is displayed superimposed on the appearance image of the subject by the optical camera, and when the size of the displayed area is changed, the X-ray is linked.
• the X-ray CT apparatus uses the same optical camera and image processing unit as those in the above-described inventions, the object shape and size, and positional information with respect to the rotation axis of the rotary stage, and X-ray air calibration. Sometimes used. Air calibration is an essential procedure for accurately determining the X-ray luminance radiation distribution before CT imaging. In practice, the X-ray source tube voltage, tube current, X-ray source and X-ray detection are used. After determining the distance between the instruments, remove the subject from the rotation stage and place it outside the field of view of the X-ray detector. Use the detector output as a reference image to determine the 100% level of each pixel by integrating the output of the detector.
• the distance between the X-ray source and the X-ray detector can be changed, or the area size of the X-ray detector can be changed. In the case of further trouble (when using a multi-image tube), it is necessary to perform this air calibration again.
• the movement of the rotary stage and Z or the xy table when it is placed are The table can be moved to automatically retract the subject outside the field of view of the X-ray detector.
• the present invention it is possible to prevent the X-ray source and the subject from interfering (collision) without the operator's special attention, and the subject to the X-ray source as much as possible. It is possible to easily obtain a high-magnification shooting magnification and a bright fluoroscopic image.
• the rotation direction that can bring the subject closer without interfering with the X-ray source when the subject is rotated is determined.
• the operator should pay attention to the direction of rotation of the rotary stage and the distance to the X-ray source, even when obtaining a partial tomographic image of a plate-like object such as a substrate at the highest possible magnification. A high-magnification tomographic image can be easily obtained.
• the X-ray CT apparatus since the CT-capable region determined by the positions of the X-ray source, the X-ray detector, and the rotary stage is displayed superimposed on the appearance image of the subject, Combined with the function to bring the subject as close as possible to the X-ray source without interfering with the X-ray source, the work before CT imaging can be greatly reduced, and the tomographic image of the intended area can be maximized. It becomes easy to obtain under the enlargement ratio.
• the subject is automatically detected at the time of air calibration using the shape and size of the subject obtained by image processing using the appearance image of the subject and the positional information with respect to the rotation axis. Since the X-ray detector is moved out of the field of view, the calibration work can be facilitated when the distance between the X-ray source and the X-ray detector is changed.
• FIG. 1 A configuration diagram of an embodiment of the present invention, which is a diagram showing a schematic diagram showing a mechanical configuration and a block diagram showing a system configuration.
• FIG. 2 is an explanatory diagram of a method for calculating the diameter of a circle C of a CT imaging possible region in the CT imaging region computing unit 16c in the embodiment of the present invention.
• FIG. 3 is an explanatory diagram of a display example by the display unit 14 in the embodiment of the present invention.
• FIG. 4 (A) is a plan view showing an example of a state in which the rotary stage 3 is positioned by the stage position setting unit 16d of the embodiment of the present invention, and (B) is a stage position of the embodiment of the present invention.
• FIG. 7 is a side view showing an example of a state where the rotary stage 3 is positioned by the setting unit 16d
• FIG. 5 is an explanatory view of an example of movement of the rotary stage 3 during air calibration in the embodiment of the present invention.
• FIG. 6 (A) is an operation explanatory diagram when moving the xy table 5 in the embodiment of the present invention, and is a plan view of the state before the movement of the xy table 5, and (B) is a diagram of the present invention.
• FIG. 6 is an operation explanatory diagram when moving the xy table 5 in the embodiment, and is a front view showing a state before the xy table 5 is moved.
• FIG. 7 (A) is an operation explanatory diagram when moving the xy table 5 in the embodiment of the present invention, and is a plan view of the state after the xy table 5 is moved.
• FIG. 5 is an operation explanatory diagram when the xy table 5 is moved in the embodiment of the invention, and is a front view of the state after the xy table 5 is moved.
• FIG. 8 (A) is an explanatory diagram of a method of limiting the rotation direction of the subject W when half scan is selected in the embodiment of the present invention, and (B) is a half view in the embodiment of the present invention.
• FIG. 6 is an explanatory diagram of a method for limiting the direction of rotation of a subject W when scanning is selected.
• FIG. 9 is a plan view of relevant parts showing an example of the positioning state of the subject W when half scanning is selected in the embodiment of the present invention.
• FIG. 1 is a configuration diagram of an embodiment of the present invention, and is a diagram illustrating a schematic diagram showing a mechanical configuration and a block diagram showing a system configuration.
• An X-ray detector 2 is disposed facing the X-ray source 1, and a rotation stage 3 for rotating the subject W is disposed therebetween.
• the rotation stage 3 is rotated about a rotation axis R in the z-axis direction orthogonal to the X-axis direction along the X-ray optical axis L from the X-ray source 1 and is orthogonal to each other by the stage moving mechanism 4 It can move in the X, y and z axis directions.
• the rotary stage 3 and the stage moving mechanism 4 are driven and controlled by a drive signal supplied from the stage controller 11. Further, on the rotary stage 3, an xy table 5 for mounting the subject W and moving it in the X and y axis directions is provided.
• This xy table 5 is a drive signal supplied from the table controller 12. The drive is controlled by the number.
• the X-ray detector 2 is movable in the X-axis direction, and its position in the X-axis direction can be changed by a driving signal supplied from a detector position controller force (not shown).
• the subject W is placed on the xy table 5 and irradiated with X-rays, and is rotated about the rotation axis R, and transmitted through the X-ray detector 2 at every minute rotation angle.
• the CT image reconstruction calculation device 13 uses the X-ray transmission data of the object W for 360 ° (180 ° + ⁇ in the case of half scan described later) captured in this way, and is orthogonal to the rotation axis R.
• X — Builds a tomographic image of the subject W sliced along a plane along the y plane and displays it on the display 14.
• the optical camera 6 having the same power as the CCD and the lens is disposed on the rotation axis R in a posture facing vertically downward.
• the optical camera 6 is coupled to the stage drive mechanism 4 by a column (not shown) or the like, and moves as the rotary stage 3 moves in the X, y, and z-axis directions. It is located on the rotation axis R.
• the video signal from the optical camera 6, and thus the video signal of the rotating stage 3, the xy table 5, and the subject W to be placed on / from the rotating stage 3, is sent to the arithmetic control device via the image data capturing circuit 15.
• the images are taken into 16 image processing units 16a and 16b.
• the image processing unit 16a uses the video signal from the optical camera 6 to determine the shape and size of the subject W and the positional relationship with respect to the rotation axis R.
• the image composition unit 16b synthesizes the appearance image of the subject W by the optical camera 6 and the CT imageable region obtained by the CT image region computation unit 16c described later and displays them on the display 14.
• the arithmetic and control unit 16 is actually composed of a computer and its peripheral devices, and operates so as to realize the functions of the installed program. In FIG. For the sake of convenience, the installed program has a block diagram for each function.
• the arithmetic control device 16 is given a command for manually moving the rotary stage 3, the xy table 5, or the X-ray detector 2, and various other commands.
• the operation unit 17 is connected.
• the position information of the stage controller 11 and the detector position controller force of the rotary stage 3 and the X-ray detector 2 and the effective width of the light receiving surface of the X-ray detector 2 are calculated.
• a circle representing the CT imaging possible area around the rotation axis R is calculated. That is, as shown in the plan view of FIG. 2, the distance in the X-axis direction between the X-ray source 1 (focal point, hereinafter the same) and the rotation axis R is A, and the light received by the X-ray source 1 and the X-ray detector 2 is the same. If the distance in the X-axis direction to the surface is B and the effective width in the y-axis direction of the light-receiving surface of X-ray detector 2 is D, CT imaging The diameter ⁇ of the circle C representing the shadowable area is
• the circle C with the diameter ⁇ calculated in this way is displayed on the display unit 14 by being combined with the appearance image of the subject W by the image combining unit 16b as shown in the display example of the display unit 14 in FIG.
• the stage position setting unit 16d uses the information related to the shape and size of the subject W and the positional relationship with respect to the rotation axis R supplied from the image processing unit 16a to rotate the subject W around the rotation axis. ° When rotating, find the position of the rotary stage 3 where the circle drawn by the point on the subject W farthest from the rotation axis R and the X-ray source 1 are separated by a preset small gap, A drive control signal is supplied to the stage controller 11 via a veg drive controller 16e that automatically moves the rotary stage 3 to that position.
• subject W is mounted on xy table 5 with rotary stage 3 and xy table 5 positioned at a specified position, for example, the origin, the output of optical camera 6 is captured, and subject W is captured by image processing unit 16a.
• image processing unit 16a The contour, the size, and the positional relationship with respect to the rotation axis R are obtained.
• the stage position setting unit 16d causes the subject W not to interfere with the X-ray source 1 when the subject W is rotated about the rotation axis R, and the shadow is the most X.
• a drive signal is supplied to the rotary stage 3 via the veg drive controller 16e and the stage controller 11 that move the rotary stage 3 to a position approaching the radiation source 1.
• Fig. 4 (A) shows the state after movement
• Fig. 4 (B) shows a side view.
• the SOD is set to the smallest SOD that can obtain the X-ray fluoroscopic data of the brightest subject W having the highest magnification.
• the X-ray detector 2 is moved in the X-axis direction to adjust the region intended for imaging to the circle c, but for this adjustment, the subject W is moved in the X-axis direction. You can move it.
• the stage moving mechanism 4 can be driven manually or automatically to adjust the subject position!
• the stage moving mechanism 4 is driven to drive the subject. Move W in the X-axis direction and determine SOD.
• SOD When determining the SOD, after the operator changes the size of the circle C displayed on the display 14 to the circle C ′ by operating the operation unit 17, the circle C, which is an actual CT imaging possible region, is changed to the operator. It can also be configured to automatically move the subject W in the X-axis direction by driving the stage moving mechanism 4 so as to coincide with the specified circle C ′.
• the stage position setting unit 16d is based on information on the shape and size of the object from the image processing unit 16a and the positional relationship with the rotation axis R as shown in FIG.
• the rotary stage 3 and the Z or xy stage are driven to automatically move in the y axis direction or in the X axis direction.
• a drive signal is supplied to the rotary stage 3 and the Z or xy table 5 via the control unit 16e, the stage controller 11 and / or the table controller 12. Then, perform air calibration in this state. After performing this air calibration, return rotary stage 3 and Z or xy table 5 to the position before air calibration.
• CT imaging is performed.
• the subject W can be placed on the X-ray source 1 as much as possible without interfering with the X-ray source 1 without confirmation by the operator before CT imaging.
• CT images can be taken at a high magnification, and X-ray fluoroscopy data can be obtained as much as possible even when photographing at the same magnification, and images with good SN can be obtained. Further, even when the xy table 5 is moved, the work for confirming the interference of the subject W with the X-ray source 1 becomes unnecessary.
• Half-scan is a force that can make the SOD shorter, especially when a plate-like subject W is magnified when the center power is shifted. Stated.
• the direction of rotation of the rotary stage 3 is limited to the direction in which the point farthest from the rotation axis R on the subject W is away from the X-ray source 1.
• the subject W has a small gap ⁇ with respect to the X-ray source 1.
• the operator does not pay attention to the rotation direction of the subject W, and confirms the position of the rotary stage 3 by trial and error.
• the optimal SOD is set, and it is mounted on the printed wiring board as described above, and when performing CT imaging around each of the multiple IC chips with a large magnification ratio
• the burden on the operator can be greatly reduced.
• the optical camera 6 is always directly above the rotation axis R as in the above-described embodiment.
• the optical camera 6 is fixed to the device frame etc., and the rotation axis R is positioned directly below the optical mela 6 by, for example, positioning the rotary stage 3 at the origin position.
• an external appearance image of the subject W may be captured and stored in this state.
• a circle C representing the CT imaging possible area obtained by the CT imaging area computing unit 16c and The appearance image of the subject W to be combined and displayed on the display 14 can be taken and memorized in advance.
• the subject W does not interfere with the X-ray source 1 based on the shape and size of the subject W obtained by the image processing unit 16a and the positional information with respect to the rotation axis R, and is possible.
• Example of positioning the rotary stage 3 to a position as close as possible When the rotary stage 3 is moved by manual operation, the rotary stage 3 is rotated at that position according to the position of the rotary stage 3 every moment. Automatically determines whether the subject W interferes with the X-ray source 1, and issues an alarm or prohibits rotation according to the determination result.
• the present application is based on a Japanese patent application filed on November 12, 2004 (Japanese Patent Application No. 2004-328401), the contents of which are incorporated herein by reference.

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• 2005
  • 2005-10-26 KR KR1020077010057A patent/KR100888530B1/ko active IP Right Grant
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