JP4965841B2 - X-ray shutter mechanism, X-ray imaging apparatus including the same, and X-ray imaging method therefor - Google Patents

Description

  The present invention relates to an X-ray shutter mechanism for taking a transmission image of an object when observing and inspecting the internal structure and internal defect of the object in a nondestructive inspection and the like, an X-ray imaging apparatus including the X-ray shutter mechanism, and The present invention relates to the X-ray imaging method.

Conventionally, in a nondestructive inspection, an X-ray fluoroscope has been used as a method for observing the internal structure of a subject and detecting internal defects. By taking a transmission image, for example, an electrical connection failure of a solder portion of various electronic components mounted on a substrate or the like is detected, and the introduction of a defective product is prevented in advance.
Various studies have been made on the X-ray shutter mechanism used for photographing a transmission image using such X-rays.
For example, (Patent Document 1) states that “a rotating drum having an opening through which X-rays pass in a direction perpendicular to the rotation axis is rotated at a predetermined speed and passes through X-rays for a predetermined short period of time every predetermined period. A rotary drum type X-ray beam opening / closing device having an X-ray shutter mechanism for obtaining intermittent radiation, and the X-ray passage opening of the rotary drum has a divergent opening defined by radiation from the rotating shaft. An X-ray irradiation control device characterized in that "is disclosed.
(Patent Document 2) states that “at least two shielding plates arranged between an X-ray focal point and an X-ray irradiation field and capable of opening and closing, and two opposingly arranged in the vicinity of the shielding plates. A rotating member, a connecting member that simultaneously rotates the two rotating members, a power transmission member that is connected to the respective rotating members, and that converts the rotational motion of the rotating members into parallel motion to open and close the shielding plate; An intermittent X-ray exposure apparatus comprising a drive source that performs a rotational movement of the rotating member is disclosed. "
Japanese Patent No. 3334747 JP-A-56-76200

However, the above conventional techniques have the following problems.
(1) The X-ray shutter mechanism used in the X-ray irradiation control device of (Patent Document 1) rotates a rotating drum having an opening through which X-rays pass in a direction perpendicular to the rotation axis at a predetermined speed. For this reason, the X-ray shutter mechanism itself is increased in size and the distance between the X-ray source and the subject is increased, so that the enlargement ratio of the image is likely to decrease, and is not suitable for industrial use for examining a small subject. It had the problem that.
In addition, the rotating drum having the opening portion must be formed of an X-ray shielding material. However, the processing is complicated and lacks productivity, the vibration increases as the weight increases, and the image quality tends to decrease. In industrial applications where the observation object is minute, there is a problem that the detection performance of minute defects and the like is not reliable.
Furthermore, since a free space is eliminated around the focal point of the X-ray source by arranging the rotating drum, there is a problem that the X-ray irradiation to the subject is likely to be obstructed, and handling and versatility are lacking. It was.
(2) Since the X-ray intermittent irradiation apparatus of (Patent Document 2) has a structure in which one rectangular hole is opened and closed by two shielding plates, it is surely square if the two shielding plates are not completely synchronized. There is a problem that the hole cannot be closed and the operation stability is lacking and it is difficult to make the two shielding plates contact each other without a gap, and the X-ray cannot be completely shielded and the reliability is lacking. Was.
Also, in the case of a structure in which one square hole is opened and closed by two shielding plates, when opening the square hole, it is opened from the central part, and when closing the square hole, it is closed from both ends. The exposure time is long, the exposure time at both ends is shortened, the X-rays cannot be uniformly irradiated to the irradiation field, and the image quality is likely to deteriorate. .

  The present invention solves the above-described conventional problems, and reciprocates an X-ray shutter plate that includes a single window portion and two X-ray shielding portions provided on both sides of the window portion as a set. Provides an X-ray shutter mechanism that can easily control the presence / absence of irradiation of X-rays and the irradiation time by opening and closing the irradiation port of the X-ray source, and having a small, lightweight, and space-saving movable part. X-rays with excellent reliability can be obtained by irradiating the subject with a uniform X-ray dose so that a high-quality transmission image can be obtained. An object of the present invention is to provide an imaging apparatus and an X-ray imaging method that can capture a plurality of transmission images continuously in a short time and is excellent in practicality and functionality.

In order to solve the above problems, an X-ray shutter mechanism of the present invention, an X-ray imaging apparatus including the same, and an X-ray imaging method thereof have the following configurations.
The X-ray shutter mechanism according to claim 1 of the present invention includes: (a) an X-ray shutter plate having a window portion and two X-ray shielding portions provided on both sides of the window portion; (B) a drive motor, a disc crank disposed on the drive motor, one end swingably disposed on one end of the X-ray shutter plate, and the other end pivotable on the disc crank An X-ray shutter opening / closing section that opens and closes an X-ray source irradiation opening by reciprocating the X-ray shutter plate by converting the rotational movement of the disc crank into a reciprocating linear movement. The speed at which the irradiation port is opened and the speed at which the irradiation port is closed are equal, and each X-ray is determined from the rotation radius of the disc crank and the center position of the window portion of the X-ray shutter plate. The length to the center position of the shielding part is the same.
This configuration has the following effects.
(1) Since the X-ray shutter plate has a window portion and two X-ray shielding portions provided on both sides of the window portion, the X-ray shutter plate is reciprocated by the X-ray shutter opening / closing portion. Thus, one image can be taken in one way and two times in reciprocation, the operation of the X-ray shutter opening / closing unit is not wasteful, and a plurality of images can be taken in a short time, which is excellent in practicality.
(2) The X-ray shutter plate can be opened and closed by reciprocating the X-ray shutter plate by means of an X-ray shutter opening / closing unit provided continuously with the X-ray shutter plate, so that irradiation can be reliably performed except during imaging. It is possible to prevent the X-ray from being irradiated by closing the mouth, and to obtain a pulse X-ray necessary for imaging.
(3) A window is provided between the two X-ray shielding parts of the X-ray shutter plate, and the speed at which the irradiation port is opened and the speed at which the irradiation port is closed are set to be equal, so that Can be obtained, and a high-quality transmission image can be obtained that enables highly accurate image analysis.
(4) Since the X-ray shutter opening / closing part is a rotary linear conversion mechanism that converts the rotational movement of the disc crank into a reciprocating linear movement, the X-ray shutter plate can be reciprocated only by rotating the drive part. It is possible to perform uniform X-ray irradiation on the subject by equalizing the opening speed and the closing speed.
(5) The shutter speed can be easily changed by changing the speed of the rotational motion, which is excellent in versatility and practicality.
(6) Since the X-ray shutter opening / closing section has a disc crank disposed in the drive motor and a link shaft connecting the X-ray shutter plate and the disc crank, the rotary motion of the disc crank with a simple configuration Can be converted into a linear motion to reciprocate the X-ray shutter plate, resulting in excellent space saving.
(7) By rotating the disc crank by a predetermined angle by the drive motor, the opening and closing of the irradiation port of the X-ray source can be easily switched, and the practicality is excellent.
(8) and the radius of rotation of the disc crank, by the length from the center position of the window portion of the X-ray shutter plate to the central position of the X-ray shielding portion of each of the same, the disc crank is rotated 90 degrees Every time, the opening and closing of the irradiation port of the X-ray source can be switched. When the disk crank is continuously rotated, photographing can be performed continuously. Further, if the rotation of the disc crank is stopped for a certain time while the irradiation port of the X-ray source is opened, X-rays can be irradiated only during that time, and the X-ray irradiation time can be arbitrarily set.

Here, it is necessary to form at least two X-ray shielding portions of the X-ray shutter plate with an X-ray shielding material such as tungsten or lead. The region to which X-rays are irradiated when the irradiation port of the X-ray source is closed is the X-ray shielding part, but the entire X-ray shutter plate including its periphery may be formed of an X-ray shielding material. In addition, if the area formed by the X-ray shielding material is reduced, the X-ray shutter plate can be reduced in weight, and the power necessary for driving the X-ray shutter plate and the vibration generated during the driving can be reduced. Excellent in properties.
The window portion is formed to be larger than the irradiation port of the X-ray source, but the boundary between the at least two X-ray shielding portions is preferably formed in a straight line perpendicular to the operation direction of the X-ray shutter plate. Thereby, when the X-ray shutter plate crosses the irradiation port of the X-ray source, the X-ray shutter plate is opened and closed at a uniform speed, and uniform X-ray irradiation can be performed to obtain a high-quality transmission image.
Further, by forming the window portion larger than the irradiation port of the X-ray source, the X-ray shutter plate can be stopped in a state where the irradiation port is completely opened, and imaging can be performed with a longer X-ray irradiation time. . If the speed at which the irradiation port is opened is equal to the speed at which the irradiation port is closed, the stop time of the X-ray shutter plate in the opened state of the irradiation port can be arbitrarily set.
In a macrofocus X-ray source with an irradiation port as small as several millimeters, the X-ray shutter plate can be formed in an elongated plate shape with a width of 1 cm or less, so that a small and lightweight configuration can be realized and the apparatus can be downsized. Easy and easy to handle and save space.

  The X-ray shutter opening / closing unit only needs to be able to linearly reciprocate the X-ray shutter plate between the two X-ray shielding units, and the movement of the drive unit itself may be any movement. For example, in order to directly drive the X-ray shutter plate in a straight line, one end of the X-ray shutter plate is connected to the tip of an extendable drive unit such as a piston cylinder, and the drive unit is linearly expanded and contracted. A device that reciprocates the X-ray shutter plate, a device that connects one end of the X-ray shutter plate to a reciprocating drive unit such as a linear motor or a solenoid, and reciprocates the X-ray shutter plate together with the drive unit are suitable. Used. In order to reciprocate the X-ray shutter plate by converting the rotational motion of the drive unit into a linear motion, a crank portion such as a crankshaft or a disc crank is linked to one end portion of the X-ray shutter plate and the crank portion The slider crank mechanism that reciprocates the X-ray shutter plate by the rotation of the X-ray shutter plate. A rack is formed on one end of the X-ray shutter plate, and the X-ray shutter plate is reciprocated by rotating the pinion meshed with the rack forward and backward. A cam, such as an involute cam or a heart cam, which is shifted in phase at both ends of the X-ray shutter plate, and reciprocating the X-ray shutter plate by rotating each cam; The link portion connected to one end is guided by a single groove formed on the outer periphery of the cylindrical cam, and the X-ray shutter plate is moved in the axial direction of the cylindrical cam by rotating the cylindrical cam. We shall be moving or the like is preferably used.

The X-ray shutter mechanism is preferably provided with a guide portion that slidably holds the X-ray shutter plate in parallel with the reciprocating direction of the X-ray shutter plate. Thus, the X-ray shutter plate can be held substantially parallel to the irradiation port, and the X-ray shutter plate can be reliably reciprocated. In addition, when a bearing etc. are arrange | positioned at the both sides of an X-ray shutter board, the resistance between an X-ray shutter board and a guide part can be reduced, and it is excellent in the stability of reciprocation. The guide portion may be anything that can hold the X-ray shutter plate so as to be able to reciprocate. The guide portion can freely slide on the top surface and bottom surface of the X-ray shutter plate or the link portion connected to the X-ray shutter plate. It may be held.
If the stroke of the reciprocating motion of the X-ray shutter plate can be long, a plurality of window portions and X-ray shielding portions may be alternately formed on the long plate-shaped X-ray shutter plate. A plurality of transmission images can be taken continuously by one operation, and the photographing time can be greatly shortened.
When the rotational motion is converted into a linear motion by the X-ray shutter opening / closing section, a stepping motor (pulse motor), an AC motor, a DC motor, various servo motors, and the like are preferably used as a driving source for the rotational motion. When a stepping motor is used, the rotation angle and rotation speed change in proportion to the number and frequency of input pulses, so that the movement amount and movement speed of the X-ray shutter plate can be easily controlled. For a stepping motor or the like that can freely control the rotation direction, the same function can be realized even if the rotation direction is reversed in the forward and reverse directions. In particular, it is preferably used when a rack and pinion mechanism or the like is applied as the X-ray shutter opening / closing part.

When the X-ray shutter opening / closing section has a configuration that is a rotation linear conversion mechanism that converts the rotational movement of the cam into a reciprocating linear movement , the X-ray shutter plate can be reciprocated only by rotating the drive section. It is possible to perform uniform X-ray irradiation on the subject by equalizing the opening speed and the closing speed.
In addition, the shutter speed can be easily changed by changing the speed of the rotational motion, which is excellent in versatility and practicality.

Here, as the drive source of the X-ray shutter opening / closing unit, the above-described stepping motor, AC motor, DC motor, various servo motors, and the like are preferably used.
By controlling the rotation speed using a stepping motor or the like, the opening speed and the closing speed of the irradiation port by the X-ray shutter plate can be made substantially equal. When the rotation speed is not controlled and the rotation speed (angular speed) is constant, the shutter speed is the slowest at the closed position of the X-ray shutter plate and the fastest at the open position of the X-ray shutter plate. The time required to move from the closed state or the closed state to the open state is substantially constant. Therefore, the average opening speed and closing speed are substantially equal, and the X-ray irradiation time can be kept substantially constant in the reciprocating operation of the X-ray shutter plate, so that the subject can be irradiated with substantially uniform X-rays. There is no practical problem because it can be done. Further, since the shutter speed is the slowest at the closed position of the X-ray shutter plate, the position control of the closed position can be easily and reliably performed, and the safety is excellent.

As the cam, a flat plate cam, a cylindrical cam, or the like such as the involute cam or the heart cam described above can be used. For involute cams, heart cams, etc. that cannot reciprocate the X-ray shutter plate as a single unit, arrange the X-ray shutter plates at opposite ends in the longitudinal direction and synchronize each cam with the drive motor. And rotate it. Further, a cam may be provided only on one end side in the longitudinal direction of the X-ray shutter plate, and an elastic member such as a coil spring may be provided on the other end side.
Further, as the crank, the above-described crankshaft, disk crank, or the like can be suitably used, and various slider crank mechanisms can be used as the rotating linear conversion mechanism.

  If the guide portion for holding the X-ray shutter plate is provided in parallel with the reciprocating direction of the X-ray shutter plate as described above, the X-ray shutter plate and the irradiation port can be held substantially in parallel. The line shutter plate can be reliably reciprocated. The guide portion may have any configuration as long as it can hold the X-ray shutter plate so as to be able to reciprocate, but the X-ray shutter plate is held from both sides by two concaves having a substantially U-shaped cross section. Are preferably used. In particular, when a bearing is provided between the guide portion of the concave stripe and both side portions of the X-ray shutter plate, the resistance between the X-ray shutter plate and the guide portion can be reduced and the reciprocating operation can be performed smoothly. It is excellent in operational stability. Alternatively, concave grooves may be formed on both sides of the X-ray shutter plate and held by the convex guides from both sides.

A second aspect of the present invention is the X-ray shutter mechanism according to the first aspect, wherein a notch portion is formed in an outer peripheral portion of the disc crank of the X-ray shutter opening / closing portion , and the disc crank is It has the structure provided with the optical sensor which detects the said notch part .
With this configuration, in addition to the operation of the first aspect , the following operation is provided.
(1) Since the amount of movement of the X-ray shutter plate is determined by the rotation angle of the disc crank, a notch is formed in the outer periphery of the disc crank, and this is detected by a transmissive optical sensor such as a photohead Thus, it is possible to easily determine whether the irradiation port of the X-ray source is in an open state or a closed state.

Here, the same drive motor as described above is preferably used.
Further, a notch or a protrusion may be provided on the X-ray shutter plate, and its movement (position) may be directly detected.

The X-ray imaging apparatus according to claim 3 is an X-ray source, an X-ray shutter mechanism according to claim 1 or 2 disposed opposite to an irradiation port of the X-ray source, and an X of the X-ray shutter mechanism. And an image sensor that is disposed opposite to the X-ray source with a line shutter plate interposed therebetween and detects a transmission image of the subject.
This configuration has the following effects.
(1) An X-ray shutter mechanism disposed opposite to the irradiation port of the X-ray source, an image sensor disposed opposite to the X-ray source across the X-ray shutter plate of the X-ray shutter mechanism, and detecting a transmission image of the subject. When the transmission image is not taken, the X-ray shutter plate of the X-ray shutter mechanism closes the X-ray source irradiation port to stop the X-ray irradiation, and the transmission image is taken. X-rays can be irradiated by opening the irradiation port.
(2) With the X-ray shutter mechanism, the opening / closing speed of the X-ray shutter plate, the opening time of the irradiation port of the X-ray source, and the like can be easily changed, and imaging under various conditions can be performed in a short time. Excellent versatility and practicality.
(3) Since the opening and closing of the X-ray source irradiation port can be switched by the X-ray shutter mechanism, an X-ray source that continuously emits X-rays is used in addition to the X-ray source that irradiates X-rays in pulses. Therefore, stable X-ray output can be maintained, and the reliability is excellent.

Here, as the image sensor, a CCD type or CMOS type is preferably used. In particular, an image sensor formed in a planar shape is less likely to be distorted in a captured image, can be easily miniaturized, and can be suitably used for observation of a minute object. By combining with the X-ray shutter mechanism, uniform X-ray irradiation can be performed on the entire surface of the subject with high accuracy, enabling high-accuracy image analysis and excellent reliability. The X-ray shutter mechanism can also be applied to a conventional image sensor such as an image intensifier (image intensifier).
By providing the X-ray imaging apparatus with a display for displaying the captured transmission image, the captured image can be confirmed immediately, and the imaging can be performed efficiently while changing the imaging direction and magnification. be able to. Further, when the X-ray fluoroscopic apparatus is provided with a subject holding table that holds the subject and can move in the X, Y, and Z directions, the observation position and the observation depth of the subject can be arbitrarily set. In addition, when the subject holding table can rotate around the X, Y, and Z axes, the orientation and observation angle of the subject can be arbitrarily set, and the observation workability is excellent. Furthermore, by providing a control unit such as a personal computer, operations of the subject holding table and the X-ray shutter mechanism can be controlled in synchronization, and imaging under various conditions can be performed in a short time. Excellent observation work efficiency and practicality.

Note that the data of the photographed transmission image can be stored in various storage media such as a hard disk, MO, CD, and DVD provided in the control unit. As a result, the stored data can be easily managed, and the data can be taken out and displayed on a display as appropriate, or the image can be processed by image processing software or the like. In addition, when the display device has a stereo display function, two types of transmission images with different angles can be selected from the captured transmission images and displayed in stereo on the display device. The state and position of structures and internal defects can be observed three-dimensionally. As a display having a stereo display function, an anaglyph stereoscopic display using red and blue glasses, a cross-stereoscopic display or a parallel stereoscopic display by autostereoscopic viewing, a liquid crystal display or a stereoscopic display capable of independent stereoscopic display. Visual glasses or a combination of a display capable of switching screens and liquid crystal shutter glasses is preferably used.
Further, by installing software for analyzing the state of the inside of the subject, the state of defects, etc. based on these data, and determining quality, etc., it can be suitably used as an inspection apparatus or the like.

The X-ray imaging method according to claim 4 is a shutter opening / closing step of opening / closing an irradiation port of the X-ray source of the X-ray imaging apparatus according to claim 3 by the X-ray shutter mechanism according to claim 1 or 2 ; A transmission image capturing step of irradiating the subject with X-rays at a position where the window portion of the X-ray shutter plate and the irradiation port of the X-ray source overlap, and capturing a transmission image with the image sensor. It has a configuration.
This configuration has the following effects.
(1) Since the X-ray shutter mechanism has a shutter opening / closing process for opening and closing the X-ray source irradiation port, X-rays continuously generated by the X-ray source can be converted into pulse X-rays at the irradiation port and transmitted. In the image capturing process, the X-ray shutter plate window and the irradiation port of the X-ray source of the X-ray imaging apparatus overlap each other to reliably irradiate the subject with the required amount of X-rays and transmit the image through the image sensor. Can be taken.
(2) By changing the imaging angle and imaging depth of the subject while repeating the shutter opening / closing process and the transmission image imaging process, continuous imaging can be performed in a short time, and the captured images are switched in time series. By displaying the image, it is possible to display a simple moving image and excel in versatility and efficiency of observation work.

  Here, by controlling the X-ray shutter mechanism and the image sensor by the control unit, the opening / closing timing of the irradiation port by the X-ray shutter plate and the timing of image capture by the image sensor can be synchronized, and reliably in a short time. A transmission image can be taken.

As described above, according to the X-ray shutter mechanism of the present invention, the X-ray imaging apparatus including the same, and the X-ray imaging method, the following advantageous effects can be obtained.
According to invention of Claim 1, it has the following effects.
(1) An X-ray shutter plate having two X-ray shielding portions connected on both sides across a window portion is reciprocated by an X-ray shutter opening / closing portion, so that one image is photographed once in one way and twice in two reciprocations. It is possible to provide an X-ray shutter mechanism that can perform imaging, has no waste in the operation of the X-ray shutter opening / closing unit, can perform imaging a plurality of times in a short time, and has excellent practicality.
(2) The X-ray shutter plate can be opened and closed by reciprocating the X-ray shutter plate by means of an X-ray shutter opening / closing unit provided continuously with the X-ray shutter plate, so that irradiation can be reliably performed except during imaging. It is possible to provide an X-ray shutter mechanism excellent in practicality and reliability that can prevent the X-ray irradiation by closing the mouth and obtain pulse X-rays necessary for imaging.
(3) A window is provided between the two X-ray shielding parts of the X-ray shutter plate, and the speed at which the irradiation port is opened and the speed at which the irradiation port is closed are set to be equal, so that Therefore, it is possible to provide an X-ray shutter mechanism with excellent observation workability and reliability that can perform high-accuracy image analysis using a high-quality transmitted image with a uniform irradiation amount.
(4) Highly accurate and uniform reproducible X-ray irradiation enables high-accuracy image analysis, facilitates automated inspections, and further expands the application to sites that require X-ray fluoroscopy. An X-ray shutter mechanism with excellent practicality and reliability that can be realized can be provided.
(5) Since the X-ray shutter opening / closing part is a rotary linear conversion mechanism that converts the rotational movement of the disc crank into a reciprocating linear movement, the X-ray shutter plate can be reciprocated only by rotating the drive part. It is possible to perform uniform X-ray irradiation on the subject by equalizing the opening speed and the closing speed.
(6) It is possible to provide an X-ray shutter mechanism excellent in versatility and practicality that can easily change the shutter speed by changing the rotational speed.
(7) Since the X-ray shutter opening / closing section has a disc crank disposed in the drive motor and a link shaft connecting the X-ray shutter plate and the disc crank, the rotary motion of the disc crank with a simple configuration It is possible to provide an X-ray shutter mechanism excellent in space saving, productivity, and long life, in which the X-ray shutter plate can be reciprocated by converting the motion into a linear motion.
(8) An X-ray shutter excellent in handling, practicality, and versatility that can easily switch between opening and closing the irradiation port of the X-ray source by rotating the disc crank by a predetermined angle with a drive motor. A mechanism can be provided.
(9) By making the rotation radius of the disc crank equal to the pitch from the window portion of the X-ray shutter plate to each X-ray shielding portion, every time the disc crank rotates 90 degrees, the X-ray source The opening and closing of the irradiation port can be switched. When the disk crank is continuously rotated, photographing can be performed continuously. Further, if the rotation of the disc crank is stopped for a certain time while the irradiation port of the X-ray source is opened, X-rays can be irradiated only during that time, and the X-ray irradiation time can be arbitrarily set.

According to invention of Claim 2, in addition to the effect of Claim 1, it has the following effects.
(1) Since the amount of movement of the X-ray shutter plate is determined by the rotation angle of the disc crank, a notch is formed in the outer periphery of the disc crank, and this is detected by a transmission type optical sensor such as a photo head. Thus, it is possible to easily determine whether the irradiation port of the X-ray source is in an open state or a closed state.

According to invention of Claim 3 , it has the following effects.
(1) An X-ray shutter mechanism disposed opposite to the irradiation port of the X-ray source, an image sensor disposed opposite to the X-ray source across the X-ray shutter plate of the X-ray shutter mechanism, and detecting a transmission image of the subject. When the transmission image is not taken, the X-ray shutter plate of the X-ray shutter mechanism closes the X-ray source irradiation port to stop the X-ray irradiation, and the transmission image is taken. It is possible to provide an X-ray imaging apparatus with excellent practicality capable of opening an irradiation port and irradiating X-rays.
(2) With the X-ray shutter mechanism, the opening / closing speed of the X-ray shutter plate, the opening time of the irradiation port of the X-ray source, etc. can be easily changed, and imaging under various conditions can be performed in a short time. An X-ray imaging apparatus having excellent versatility and practicality can be provided.
(3) By providing the X-ray shutter mechanism, a stable X-ray output can be maintained using an X-ray source that continuously emits X-rays in addition to an X-ray source that emits X-rays in a pulsed manner. An X-ray imaging apparatus with excellent reliability and versatility can be provided.
(4) Since the X-ray shutter mechanism can irradiate a uniform X-ray dose with a simple configuration, a compact and highly accurate X-ray imaging apparatus excellent in practicality can be provided by combining with a small image sensor. Can do.

According to invention of Claim 4 , it has the following effects.
(1) Since the irradiation port of the X-ray source can be opened and closed by the X-ray shutter mechanism, X-rays continuously generated by the X-ray source can be converted into pulse X-rays at the irradiation port. At the position where the window portion of the X-ray shutter plate and the irradiation port of the X-ray source of the X-ray imaging apparatus overlap, the subject is surely irradiated with the necessary amount of X-rays and the transmission image is captured by the image sensor. Therefore, it is possible to provide an X-ray imaging method having excellent reliability and practicality.
(2) By changing the imaging angle and imaging depth of the subject while repeating the shutter opening / closing process and the transmission image imaging process, continuous imaging can be performed in a short time, and the captured images are switched in time series. By displaying the images, it is possible to provide an X-ray imaging method excellent in versatility and efficiency of observation work capable of displaying a simple moving image.

Hereinafter, an X-ray shutter mechanism, an X-ray imaging apparatus including the X-ray shutter mechanism, and an X-ray imaging method according to the embodiment of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a schematic cross-sectional front view of an essential part showing a configuration of an X-ray imaging apparatus including an X-ray shutter mechanism according to Embodiment 1 of the present invention.
In FIG. 1, reference numeral 1 denotes an X-ray imaging apparatus provided with the X-ray shutter mechanism 6 in the first embodiment, 2 denotes a shielding box that covers the apparatus body of the X-ray imaging apparatus 1, and 3 controls the X-ray imaging apparatus 1. A control unit such as a personal computer, 4 is connected to the control unit 3 and is a display of the X-ray imaging apparatus 1 that displays a transmission image of the subject 20, and 5a is an X-ray tube 5 that irradiates the subject 20 with X-rays. The X-ray source 5b of the housed X-ray imaging apparatus 1 has an irradiation port 5 and 6 formed at the bottom of the X-ray source 5a, and the irradiation port 5 and 6 are arranged opposite to the irradiation port 5b of the X-ray source 5a. An X-ray shutter mechanism, 7 is an X-ray shutter plate of the X-ray shutter mechanism 6 having a window portion 8 formed substantially at the center in the longitudinal direction, and 11 is connected to the X-ray shutter plate 7 to reciprocate the X-ray shutter plate 7 X-ray shutter opening / closing of X-ray shutter mechanism 6 that moves and opens / closes irradiation port 5b of X-ray source 5a , 16 is a subject holding table for holding the subject 20, and 17 is a CCD type for detecting a transmission image of the subject 20 irradiated with X-rays arranged opposite to the X-ray source 5a across the subject holding table 16. It is a CMOS type image sensor.

By covering the parts other than the control unit 3 and the display 4 with the shielding box 2, leakage of X-rays to the outside was prevented.
The subject 20 was fixed on the subject holding table 16 by sticking with a double-sided tape. When the subject 20 is relatively large, the subject 20 may be fixed by being adsorbed by air or holding the outer shape of the subject 20.
By making the subject holding table 16 movable in the X, Y, and Z directions, the subject 20 can be moved back and forth, left and right, and up and down, and an arbitrary planar position and depth of the subject 20 can be selected. Thus, a transparent image can be taken. In addition, by enabling the subject holding table 16 to rotate around the X, Y, and Z axes, it is possible to select an arbitrary direction and angle (tilt) of the subject 20, and to perform more detailed observation. It can be carried out.
As the image sensor 17, an arbitrary one can be used. In particular, when an image sensor formed in a planar shape is used, the image is hardly distorted and suitable for observation of a minute object. The entire X-ray imaging apparatus 1 can be reduced in size and is excellent in space saving.

Since the control unit 3 can control the operations of the X-ray shutter mechanism 6, the subject holding table 16, the image sensor 17 and the like in synchronization with each other, it is possible to perform imaging under various conditions in a short time, and to observe Excellent work efficiency and practicality.
In addition, data such as transmission images and observation conditions can be stored in various storage media such as a hard disk, MO, CD, and DVD disposed in the control unit 3. As a result, the stored data can be easily managed, and the data can be taken out and displayed on the display 4 as appropriate, or the image can be processed by image processing software or the like. In particular, when the display device 4 has a stereo display function, two types of transmission images having different shooting angles can be selected from the captured transmission images and displayed on the display device 4 in a stereo manner. The internal structure of the specimen 20 and the state and position of internal defects can be observed three-dimensionally.

Next, the configuration of the X-ray shutter mechanism according to Embodiment 1 of the present invention will be described in detail.
FIG. 2A is a plan view of the main part of the back surface side of the X-ray shutter mechanism according to Embodiment 1 of the present invention, and FIG. 2B is the main part of the X-ray shutter mechanism according to Embodiment 1 of the present invention. FIG. 2C is a sectional front view, and FIG. 2C is a sectional view taken along line AA in FIG.
In FIG. 2, 9a and 9b are two X-ray shielding parts of the X-ray shutter plate 7 provided on both sides of the window part 8 formed in a substantially rectangular shape, and 10 is a concave line having a substantially U-shaped cross section. Two X-ray shutter mechanisms 6 that are formed on the X-ray shutter plate 7 in parallel with the reciprocating direction (longitudinal direction) of the X-ray shutter plate 7 and are slidably held on the bottom of the X-ray source 5a. The guide portions 10a are arranged in the longitudinal direction on both sides of the X-ray shutter plate 7 and are guided by the guide portions 10, 12 is a drive motor for the X-ray shutter opening / closing portion 11 using a stepping motor, and 12a is driven. The drive shaft of the motor 12, 13 is a disc crank of the X-ray shutter opening / closing portion 11 disposed on the drive motor 12 via the drive shaft 12 a, and 13 a is four places on the outer periphery of the disc crank 13, approximately every 90 degrees. One end of the formed notch, 14 is fixed. A link shaft of the X-ray shutter opening / closing portion 11, which is swingably disposed at one end portion of the X-ray shutter plate 7 by 14 a and is pivotally disposed on the disc crank 13 by the rotation fixing portion 14 b; Reference numeral 15 denotes a transmission type optical sensor such as a photo head which is disposed so as to sandwich the disc crank 13 and detects the notch 13a.

At least two X-ray shielding portions 9a and 9b of the X-ray shutter plate 7 are formed of an X-ray shielding material such as tungsten or lead. The X-ray shielding portions 9a and 9b are irradiated with X-rays when the irradiation port 5b of the X-ray source 5a is closed. The entire X-ray shutter plate 7 including its periphery is formed of an X-ray shielding material. May be. If the area formed by the X-ray shielding material is reduced, the X-ray shutter plate 7 can be reduced in weight, and the power necessary for driving the X-ray shutter plate 7 and the vibrations generated during the driving can be reduced. Excellent reliability.
The window 8 was formed in a substantially rectangular shape larger than the irradiation port 5b of the X-ray source 5a. Thus, when the X-ray shielding portions 9a and 9b of the X-ray shutter plate 7 cross the irradiation port 5b of the X-ray source 5a, the X-ray shutter plate 7 is aligned in the width direction (vertical direction in FIG. 2A). Thus, a high-quality transmission image can be obtained by performing uniform X-ray irradiation. The shape of the window portion 8 is not limited to this, and the shape of the boundary between the at least two X-ray shielding portions 9 a and 9 b is formed in a straight line perpendicular to the operation direction of the X-ray shutter plate 7. It only has to be.

Since the X-ray shutter mechanism 6 has the guide portion 10 that holds the X-ray shutter plate 7 in parallel with the reciprocating direction of the X-ray shutter plate 7, the X-ray shutter plate 7 and the irradiation port 5b are held substantially in parallel. And the X-ray shutter plate can be reliably reciprocated. Further, by disposing the bearings 10a on both sides of the X-ray shutter plate 7, the resistance between the X-ray shutter plate 7 and the guide portion 10 can be reduced, and the stability of the reciprocating operation is excellent. The guide portion 10 may be any member that can hold the X-ray shutter plate 7 so as to be able to reciprocate. The guide portion 10 slides on the top and bottom surfaces of the X-ray shutter plate 7 or the swinging fixing portion 14 a of the link shaft 14. It may be held freely.
In the present embodiment, the combination of the disc crank 13 and the link shaft 14 is used as the X-ray shutter opening / closing unit 11. However, the present invention is not limited to this, and the X-ray shutter plate 7 is composed of two X-ray shielding units. Any device that can linearly reciprocate between 9a and 9b may be used. For example, a drive unit such as a piston cylinder linearly expands and contracts to reciprocate the X-ray shutter plate 7, a slider crank mechanism other than the combination of the disc crank 13 and the link shaft 14, a combination of a rack and a pinion, an X-ray A cam such as an involute cam or a heart cam is disposed on one end side of the shutter plate 7 in the longitudinal direction, and a similar cam is disposed on the other end side with a phase shifted by 90 degrees, or an elastic member such as a coil spring is disposed. A device that converts a rotational motion into a linear motion using a device, a linear motor, a device that directly drives the X-ray shutter plate 7 by a solenoid, or the like is preferably used.

By using a stepping motor as the drive motor 12, the rotation angle and rotation speed of the disc crank 13 change in proportion to the number and frequency of input pulses, so the movement amount and movement speed of the X-ray shutter plate 7 can be easily achieved. Can be controlled.
And the radius of rotation of the disc crank 13, the length from the center position of the window portion 8 of the X-ray shutter plate 7 each X-ray shielding portion 9a, to the center position of 9b were almost equally formed. Thereby, every time the disc crank 13 rotates approximately 90 degrees, the opening and closing of the irradiation port 5b of the X-ray source 5a can be switched. When the disk crank 13 is continuously rotated, the X-ray shutter plate 7 can be continuously reciprocated to perform imaging. Further, if the rotation of the disc crank 13 is stopped for a certain time while the irradiation port 5b of the X-ray source 5a is opened, X-rays can be irradiated only during that period, and the X-ray irradiation time can be arbitrarily set. .
Since the amount of movement of the X-ray shutter plate 7 is determined by the rotation angle of the disc crank 13, the notch 13 a formed in the disc crank 13 is detected by the optical sensor 15, and the irradiation port 5 b of the X-ray source 5 is completely detected. An open state and a completely closed state can be reliably detected.
In the present embodiment, the open / closed state of the irradiation port 5b of the X-ray source 5a is determined by the combination of the notch 13a and the transmission optical sensor 15, but the number, shape, and shape of the notch 13a and the optical sensor 15 are determined. The arrangement and the like are not limited to the present embodiment. Further, the discriminating means for detecting the open state and the closed state of the irradiation port 5b is not limited to the present embodiment, and a reflective optical sensor may be used, or the rotation angle of the disc crank 13 is detected. In addition to this, the movement amount (position) of the X-ray shutter plate 7 may be directly detected.

The X-ray imaging method of the X-ray imaging apparatus provided with the X-ray shutter mechanism in the first embodiment formed as described above will be described based on the operation of the X-ray shutter mechanism.
FIG. 3A is a plan view of the main part on the back side of the X-ray shutter mechanism showing the closed state of the irradiation port before X-ray irradiation, and FIG. 3B shows the open state of the irradiation port during X-ray irradiation. FIG. 3C is a plan view of the main part of the back side of the X-ray shutter mechanism showing the closed state of the irradiation port after X-ray irradiation.
First, in the initial state of the shutter opening / closing process, as shown in FIG. 3A, the irradiation port 5b and the X-ray shielding part 9a of the X-ray shutter plate 7 overlap, and the irradiation port 5b is closed. When the disk crank 13 is rotated 90 degrees clockwise by the drive motor 12 from the closed state of the irradiation port 5b in FIG. 3A, the X-ray shutter plate 7 moves to the left, and FIG. As shown, the window 8 and the irradiation port 5b of the X-ray source 5a are in an open state. At this time, a transmission image capturing process is performed in which the subject 20 is irradiated with X-rays and the image sensor 17 captures a transmission image.
Further, when the disk crank 13 is rotated 90 degrees clockwise by the drive motor 12, the X-ray shutter plate 7 moves to the left, and as shown in FIG. 3C, the X-ray shield 9b and the X-ray source are moved. The irradiation port 5b of 5a overlaps to be in a closed state, and one photographing is finished.

  In addition, the amount of X-ray irradiation can be made substantially uniform by controlling the rotational speed of the disc crank 13 so that the speed at which the irradiation port 5b is opened and the speed at which it is closed are substantially equal. Further, the shutter speed when the rotational speed (angular speed) is constant without performing the rotational speed control is the slowest at the closed position of the X-ray shutter plate 7 and the fastest at the open position of the X-ray shutter plate 7. The time required from the open state to the closed state or from the closed state to the open state is substantially constant. Therefore, the average opening speed and closing speed of the irradiation port 5b are equal, and the X-ray irradiation time can be kept substantially constant in the reciprocating operation of the X-ray shutter plate 7 and is substantially uniform with respect to the subject 20. X-ray irradiation can be performed, the shutter speed can be easily controlled, and the utility is excellent.

A series of operations of the X-ray shutter mechanism 6 shown in FIGS. 3A to 3C is a shutter opening / closing process. Next, when a transmission image is to be captured, the state of FIG. 3C is the initial state of the shutter opening / closing process, and the state is shifted from the state of FIG. 3C to the state of FIG. Then, the process returns to the state shown in FIG.
As described above, every time the disc crank 13 rotates 180 degrees, the X-ray shutter plate 7 moves from the right end to the left end or from the left end to the right end to perform the shutter opening / closing process, and the transmission image capturing process is performed at the intermediate point. Therefore, the operation of the X-ray shutter plate 7 is not wasted and continuous imaging can be easily performed.

Since the X-ray shutter mechanism in the first embodiment is configured as described above, it has the following effects.
(1) Since the X-ray shutter plate 7 includes the window portion 8 and the two X-ray shielding portions 9a and 9b provided on both sides of the window portion 8, the X-ray shutter opening / closing portion 11 By reciprocating the line shutter plate 7, one image can be taken in one way and two times in reciprocation, the operation of the X-ray shutter opening / closing unit 11 is not wasteful, and a plurality of times are taken in a short time. It is possible and excellent in practicality.
(2) Since the X-ray shutter plate 7 can be reciprocated by the X-ray shutter opening / closing section 11 connected to the X-ray shutter plate 7 to open and close the irradiation port 5b of the X-ray source 5a. Therefore, the irradiation port 5b can be reliably closed to prevent the X-rays from being irradiated, and the pulse X-rays necessary for imaging can be obtained.
(3) The window portion 8 is provided between the two X-ray shielding portions 9a and 9b of the X-ray shutter plate 7, and the speed for opening the irradiation port 5b and the speed for closing the irradiation port 5b are set equal. As a result, the X-ray irradiation amount on the subject 20 becomes uniform, and a high-quality transmission image that can perform high-accuracy image analysis can be obtained.
(4) Since the X-ray shutter opening / closing part 11 includes the disc crank 13 disposed in the drive motor 12 and the link shaft 14 connecting the X-ray shutter plate 7 and the disc crank 13, the configuration is simple. The X-ray shutter plate 7 can be reciprocated by converting the rotational motion of the disc crank 13 into a linear motion, which is excellent in space saving.
(5) By rotating the disc crank 13 by a predetermined angle by the drive motor 12, opening and closing of the irradiation port 5b of the X-ray source 5a can be easily switched, which is excellent in practicality.

The X-ray imaging apparatus provided with the X-ray shutter mechanism in the first embodiment has the following operation.
(1) The X-ray shutter mechanism 6 disposed opposite to the irradiation port 5b of the X-ray source 5a and the X-ray shutter plate 7 of the X-ray shutter mechanism 6 are disposed opposite to the X-ray source 5a and transmitted through the subject 20. And an image sensor 17 for detecting an image. When a transmission image is not taken, the X-ray shutter plate 7 of the X-ray shutter mechanism 6 closes the irradiation port 5b of the X-ray source 5a to When the irradiation is stopped and a transmission image is taken, X-rays can be irradiated by opening the irradiation port 5b.
(2) The X-ray shutter mechanism 6 can easily change the opening / closing speed of the X-ray shutter plate 7, the opening time of the irradiation port 5b of the X-ray source 5a, and the like. It can be used and has excellent versatility and practicality.
(3) Since the opening and closing of the irradiation port 5b of the X-ray source 5a can be switched by the X-ray shutter mechanism 6, in addition to the X-ray source 5a that irradiates X-rays in a pulsed manner, X that continuously irradiates X-rays Since the radiation source 5a can be used, a stable X-ray output can be maintained and the reliability is excellent.

According to the X-ray imaging method of the X-ray imaging apparatus provided with the X-ray shutter mechanism in the first embodiment, the following operations are provided.
(1) Since the X-ray shutter mechanism 6 has a shutter opening / closing process of opening / closing the irradiation port 5b of the X-ray source 5a, even when X-rays are continuously generated by the X-ray source 5a, pulse X-rays are generated at the irradiation port 5b. In the transmission image capturing process, a necessary amount of X-rays can be applied at a position where the window portion 8 of the X-ray shutter plate 7 and the irradiation port 5b of the X-ray source 5a of the X-ray imaging apparatus 1 overlap. The specimen 20 can be reliably irradiated and a transmission image can be taken by the image sensor 17.
(2) By repeating the shutter opening / closing step and the transmission image photographing step while changing the photographing angle and photographing depth of the subject 20 on the subject holding table 16, continuous photographing can be performed in a short time. By switching the displayed images in time series and displaying them on the display unit 4, simple moving image display is possible, and the versatility and efficiency of observation work are excellent.

(Embodiment 2)
FIG. 4A is a plan view of the main part on the back side of the X-ray shutter mechanism according to the second embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along line BB in FIG. is there. Components similar to those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
In FIG. 4, the X-ray shutter mechanism in the second embodiment is different from that in the first embodiment in that the X-ray shutter opening / closing portion 11 a is formed with a single guide groove 23 a on the outer periphery instead of the disc crank 13. By having the cylindrical cam 23 and rotating the cylindrical cam 23 by the drive motor 12, the guide pin 14 c protruding from the tip of the link shaft 14 is moved along the guide groove 23 a, and the axial direction of the cylindrical cam 23 In other words, the X-ray shutter plate 7 is reciprocated.
Reference numeral 24 denotes a link shaft guide portion that is provided continuously with the guide portion 10 and guides the link shaft 14. Thereby, the link shaft 14 can be held and the reciprocating operation can be stabilized.

While the cylindrical cam 23 rotates once, the X-ray shutter plate 7 can be reciprocated once at a constant speed, and each time the cylindrical cam 23 rotates 90 degrees, the irradiation port 5b is opened and closed as in the first embodiment. A transmission image can be taken by switching.
At this time, the speed of reciprocation of the X-ray shutter plate 7 and the opening time of the irradiation port 5b can be controlled by controlling the rotational speed of the drive motor 12 and the like as in the first embodiment. Further, the speed of reciprocation of the X-ray shutter plate 7 corresponding to the rotational speed of the drive motor 12 can be changed by appropriately selecting the shape of the guide groove 23a. Further, the shape of the guide groove 23a can provide a period in which the X-ray shutter plate 7 does not move even when the drive motor 12 rotates, and the X-ray shutter plate 7 can be placed at the open position or the closed position of the X-ray shutter plate 7. It is also possible to stop and adjust the X-ray irradiation time and the transmission interval of transmission images.

As described above, the X-ray shutter mechanism according to the second embodiment has the following operation in addition to the operation of the first embodiment.
(1) The X-ray shutter plate 7 can be reciprocated at a constant speed simply by rotating the cylindrical cam 23 at a constant speed, and the X-ray irradiation amount to the subject 20 is made uniform, and a high-accuracy image analysis is performed. A high-quality transmission image can be obtained.
(2) By selecting the shape of the guide groove 23a formed in the cylindrical cam 23, the reciprocating speed and stop time of the X-ray shutter plate 7 can be adjusted, and the X-ray irradiation time and transmission image can be captured. The control of the interval is easy, and versatility and practicality are excellent.

  The present invention relates to an X-ray shutter mechanism for taking a transmission image of an object when observing and inspecting the internal structure and internal defect of the object in a nondestructive inspection and the like, an X-ray imaging apparatus including the X-ray shutter mechanism, and With respect to the X-ray imaging method, an X-ray source plate is reciprocally moved by reciprocating an X-ray shutter plate having a window portion and two X-ray shielding portions provided continuously on both sides of the window portion. Providing an X-ray shutter mechanism that can easily control the presence / absence of irradiation of X-rays and the irradiation time by opening and closing the irradiation port, and having a movable part that is small, lightweight, and excellent in space saving. Providing an X-ray imaging apparatus that can perform uniform X-ray irradiation with the same opening speed and closing speed, obtain a high-quality transmission image, and is excellent in reliability, and shoot a plurality of transmission images continuously in a short time. We can also provide X-ray imaging methods that are practical and functional. , And particularly the observation object can be suitably used for small industrial applications, it is possible to realize an inspection in a short time.

1 is a schematic cross-sectional front view of an essential part showing a configuration of an X-ray imaging apparatus including an X-ray shutter mechanism according to Embodiment 1 of the present invention. (A) The principal part top view of the back surface side of the X-ray shutter mechanism in Embodiment 1 of this invention (b) The principal part cross-sectional front view of the X-ray shutter mechanism in Embodiment 1 of this invention (c) FIG. b) AA arrow cross-sectional view (A) Plan view of the main part on the back side of the X-ray shutter mechanism showing the closed state of the irradiation port before X-ray irradiation (b) On the back side of the X-ray shutter mechanism showing the open state of the irradiation port during X-ray irradiation Main part plan view (c) Main part plan view on the back side of the X-ray shutter mechanism showing the closed state of the irradiation port after X-ray irradiation (A) The principal part top view of the back surface side of the X-ray shutter mechanism in Embodiment 2 of this invention (b) BB sectional view taken on the line in FIG. 4 (a)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 X-ray imaging apparatus 2 Shielding box 3 Control part 4 Display 5 X-ray tube 5a X-ray source 5b Irradiation port 6 X-ray shutter mechanism 7 X-ray shutter board 8 Window part 9a, 9b X-ray shielding part 10 Guide part 10a Bearing 11, 11a X-ray shutter opening / closing part 12 Drive motor 12a Drive shaft 13 Disc crank 13a Notch part 14 Link shaft 14a Oscillation fixing part 14b Rotation fixing part 14c Guide pin 15 Optical sensor 16 Subject holding table 17 Image sensor 20 Subject 23 Cylindrical cam 23a Guide groove 24 Link shaft guide

Claims (4)

(A) an X-ray shutter plate having a window portion and two X-ray shielding portions provided on both sides of the window portion; (b) a drive motor; and the drive motor. A disc crank, and a link shaft having one end pivotably disposed at one end of the X-ray shutter plate and the other end pivotally disposed on the disc crank. An X-ray shutter opening / closing section that converts the rotational motion of the X-ray into a reciprocating linear motion to reciprocate the X-ray shutter plate to open and close the irradiation port of the X-ray source, and the irradiation speed of the irradiation port and the irradiation equal velocity for closing the mouth, and a rotation radius of said disc crank, the length from the center position of the window portion of the X-ray shutter plate to the central position of the X-ray blocking portion of each is equal A featured X-ray shutter mechanism. The notch part is formed in the outer peripheral part of the said disc crank of the said X-ray shutter opening-and-closing part, The optical sensor which detects the said notch part of the said disc crank was provided. X-ray shutter mechanism. The X-ray source and the X-ray shutter mechanism according to claim 1, which is disposed opposite to an irradiation port of the X-ray source, and the X-ray shutter plate of the X-ray shutter mechanism so as to face the X-ray source An X-ray imaging apparatus comprising: an image sensor that is disposed and detects a transmission image of a subject. A shutter opening / closing step of opening / closing an irradiation port of the X-ray source of the X-ray imaging apparatus according to claim 3 by the X-ray shutter mechanism according to claim 1, the window portion of the X-ray shutter plate, and the X A transmission image photographing step of irradiating the subject with X-rays at a position where an irradiation port of a radiation source overlaps and photographing a transmission image with the image sensor.

Images