JP4590702B2 - X-ray inspection equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for performing nondestructive inspection using X-rays.
[0002]
[Prior art]
In general, an X-ray inspection apparatus irradiates X-rays from one side of an inspection object and captures a fluoroscopic image with an image detector disposed on the opposite side. However, this X-ray inspection apparatus cannot accurately capture an image of a desired inspection surface of an inspection object. This is because images of different surfaces apart from the desired inspection surface overlap. For example, when electronic components are mounted on both sides of a printed circuit board, even if an attempt is made to photograph the bonding state of the components mounted on the upper surface of the printed circuit board, the images of the components mounted on the lower surface will overlap.
[0003]
Therefore, laminography has been developed as a technique for detecting a tomographic image on a desired inspection surface of an inspection object. This technology obtains a plurality of different fluoroscopic images by moving two of the three elements of the X-ray source, the inspection object, and the image detector in synchronization, and based on the plurality of fluoroscopic images, The image of the object other than the desired inspection surface is excluded, and only the image on the desired inspection surface is selected and detected.
[0004]
As an example of the means for selecting and detecting only the image of the desired inspection surface as described above, there is an apparatus disclosed in Japanese Patent No. 2925841. This apparatus has an X-ray source that irradiates X-rays with a spread. The desired inspection surface of the inspection object and the image receiving surface of the image detector are synchronously rotated while being inclined at the same angle as the central axis of the X-ray spread. Thereby, an image of a desired inspection surface can be detected on the image receiving surface. However, in the apparatus disclosed in Japanese Patent No. 2925841, since the inclination angle is the same, there is a case where an overlap between the image on the desired inspection surface and the image on the other surface cannot be avoided.
[0005]
In the inspection apparatus disclosed in Japanese Patent Application Laid-Open No. 59-1116040, an X-ray source, an inspection object, and an image detector are disposed along a horizontal optical axis. Then, the fluoroscopic images at a plurality of different tilt angles are obtained by synchronously tilting while maintaining the desired inspection surface of the inspection object and the image receiving surface of the image detector in parallel.
[0006]
[Problems to be solved by the invention]
In the inspection apparatus disclosed in Japanese Patent Application Laid-Open No. 59-1106040, it is necessary to tilt the object to be inspected and the image detector.
The present invention has been made to solve the above-described problems, and can obtain various X-ray investment images from different irradiation angles, can obtain an accurate tomographic image on a desired inspection surface, and can perform inspection. An object of the present invention is to provide an X-ray inspection apparatus that does not require tilting of an object or image detection means.
[0007]
[Means for Solving the Problems]
The X-ray inspection apparatus of the present invention irradiates X-rays with a spread, and tilts the central axes of the X-rays with respect to the first and second reference planes parallel to each other, whereby the first and first An X-ray source that forms a substantially elliptic X-ray irradiation region on two reference planes, first moving means for supporting and moving the inspection object on the first reference plane, and sandwiching the inspection object Image detection arranged to face the X-ray source and having an image receiving surface for receiving X-rays transmitted through the inspection object, and converting an X-ray image appearing on the image receiving surface into an electrical signal serving as image information And second moving means for moving the image detecting means on the second reference plane in a state where the image receiving surface is parallel to the first and second reference planes, The second moving means moves the inspection object and the image detecting means to the first A straight line that is movable along the longitudinal direction of the X-ray irradiation region on the second reference plane and connects the center point of the image receiving surface of the image detecting means and the center point of the desired inspection surface of the inspection object, The X-ray source is moved so as to pass through the irradiation focal point, and the X-ray source is rotated about a rotation axis that passes through the irradiation focal point and is orthogonal to the first and second reference planes . 1. A rotating means for changing the X-ray irradiation area on the second reference plane is provided, and the first and second moving means are within the range of the X-ray irradiation area changed by rotating the rotating means. characterized in that the pre-Symbol test object, wherein each image detecting means first, it is two-dimensionally movable in the second reference plane.
[0008]
According to the above configuration, various X-ray fluoroscopic images can be obtained from different irradiation angles, and an accurate tomographic image on a desired inspection surface can be obtained. Moreover, it is not necessary to tilt the inspection object and the image detection means. Further, in X-ray examination apparatus of the present invention, further, the X-ray source, the first through the irradiation focus, the first Ri by the be pivoted about a pivot axis orthogonal to the second reference plane, the comprising a rotating means for changing the X-ray irradiation region on the second reference plane, in the range of X-ray irradiated area has changed by rotating the rotating means, the first, the second moving means inspection object, The image detecting means can be moved two-dimensionally on the first and second reference planes. Thereby, X-ray fluoroscopic images having different irradiation directions can be obtained.
[0009]
In the X-ray inspection apparatus of the present invention, a straight line that passes through the irradiation focal point of the X-ray source and is orthogonal to the first and second reference planes is the first and second reference planes at the end of the X-ray irradiation region. Interact with. Thereby, an image from a direction orthogonal to the desired inspection surface can be obtained.
[0011]
In the X-ray inspection apparatus of the present invention, the rotation axis of the X-ray source is orthogonal to the first and second reference planes. Thereby, only the direction can be changed without changing the shape of the X-ray irradiation region.
[0018]
In the X-ray inspection apparatus of the present invention, the image detection means has a phosphor surface serving as the image receiving surface, an image conversion unit for converting an X-ray image on the phosphor surface into an optical image, and the optical image. And a photoelectric conversion unit for converting into an electrical signal serving as image information. Thereby, a light and small image detection means can be provided and the burden of a moving means can be lightened.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 show an X-ray inspection apparatus according to a first embodiment of the present invention. In order to explain the structure of this apparatus, for the sake of convenience, first and second reference planes P1 and P2 are assumed. These reference planes P1 and P2 are horizontal, and the second reference plane P2 is located above the first reference plane P1.
[0020]
An X-ray source 10 is arranged below the first reference plane P1. The X-ray source 10 emits X-rays toward the upper reference planes P1 and P2 with a predetermined spread angle. The irradiation focus of X-rays is indicated by symbol F. Further, the solid angle of the spread of the X-ray is indicated by a symbol Θ in the drawing, and the center axis of the spread is indicated by a symbol C. The cross section perpendicular to the central axis C of the X-ray is circular or nearly circular.
[0021]
The X-ray source 10 is installed in a state where it is inclined to a horizontal rotating table 12 (rotating means) via an inclined table 11. Due to the inclination of the X-ray source 10, the central axis C of the X-ray is inclined with respect to the reference planes P1 and P2. As a result, as shown in FIG. 3, the X-ray irradiation region R on the reference planes P1 and P2 is elongated. Although the shape of the irradiation region R is not strictly an ellipse, it is expressed as an almost elliptical shape and is also indicated by an ellipse in the figure. The rotation axis L of the turntable 12 passes through the irradiation focal point F and is orthogonal to the reference planes P1 and P2.
[0022]
The inspection apparatus according to the first embodiment of the present invention further includes first and second moving mechanisms 21 and 22 (first and second moving means). In addition, the 1st, 2nd moving mechanisms 21 and 22 are shown smaller than the actual thing in FIG. 1, FIG. 2, and abbreviate | omitting the detailed structure.
[0023]
The first moving mechanism 21 includes a basic table and an XYZ axis moving table mounted on the basic table. The inspection object 100 is supported by the uppermost table among the XYZ axis tables. The height of the inspection object 100 is adjusted by moving the Z-axis table. In the embodiment of the present invention, in the inspection object 100, the tomographic plane on the first reference plane P1 is set as a desired inspection plane, so that the inspection target plane can be selected by adjusting the height. By moving the XY axis table of the first moving mechanism 21, the inspection object 100 is moved horizontally on the first reference plane P1.
[0024]
Similar to the first moving mechanism 21, the second moving mechanism 22 includes a basic table and an XYZ axis moving table mounted on the basic table. The image detector 30 (image detection means) is supported on the uppermost table among the XYZ axis tables. The height of the image detector 30 is adjusted by moving the Z-axis table. In the embodiment of the present invention, the plane on which the phosphor surface 31a of the image detector 30 to be described later exists is defined as the second reference plane P2. The image detector 30 is horizontally moved on the second reference plane P2 by the movement of the XY axis table of the second moving mechanism 22.
[0025]
The image detector 30 is configured by superposing a photoelectric conversion unit 32 and a plate-shaped image conversion unit 31 having a phosphor surface 31a (image receiving surface). The image conversion unit 31 receives an X-ray image transmitted through the inspection object 100 at the phosphor surface 31a, and converts the X-ray image into an optical image. The photoelectric conversion unit 32 converts this optical image into an electrical signal representing image information. The photoelectric conversion unit 32 includes a solid-state imaging device or a small and lightweight imaging camera.
[0026]
The X-ray inspection apparatus according to the first embodiment of the present invention further includes a control device 50 (control means), an image processing device 51 (image processing means), and a display device 52 (display means). The control device 50 controls the turntable 12 and the first and second moving mechanisms 21 and 22. The image processing device 51 receives position information from the control device 50, receives image information from the photoelectric conversion unit 32 of the image detector 30, performs image analysis based on both pieces of information, and displays the analysis result on the display device 52. indicate.
[0027]
Next, the operation of the X-ray inspection apparatus according to the embodiment of the present invention will be described. A printed circuit board 100 to be inspected has a flat component 102 (ball grid array component) mounted on one surface 100a via 16 solder joints 101 having a circular cross section arranged in a matrix and the other surface 100a. It is configured by mounting one rectangular component 103 on the surface 100b via solder joints 104 on both sides thereof.
[0028]
The printed circuit board 100 is placed on the uppermost table in the first moving mechanism 21 with the surface 100a on which the component 102 is mounted facing down. As described above, the height of the printed circuit board 100 is adjusted by controlling the Z table, and the lower surface 100a thereof is positioned on the first reference plane 21a. Thereby, the lower surface 100a can be selected as a desired inspection surface.
[0029]
Note that the distance between the X-ray source 10 and the desired inspection surface 100a (first reference plane P1) is sufficiently longer than the distance between the desired inspection surface 100a and the phosphor surface 31a (second reference plane P2). .
[0030]
The printed circuit board 100 and the image detector 30 are horizontally moved synchronously on the reference planes P1 and P2 by the moving mechanisms 21 and 22, are temporarily stopped at a plurality of positions, and the image detector 30 is X-rayed at each position. An image is detected and the image information is sent to the image processing device 51.
[0031]
When the printed circuit board 100 and the image detector 30 are synchronously moved horizontally, each portion of the desired inspection surface 100a and the phosphor surface 31a of the image detector 30 always maintains a one-to-one correspondence as viewed from the X-ray source 10. Yes. In other words, a straight line connecting an arbitrary point on the desired inspection surface 100a of the printed circuit board 100 and an arbitrary point on the phosphor surface 31a of the image detector 30 always sets the irradiation focus F of the X-ray source 10 during horizontal movement. A straight line connecting another arbitrary point on the desired inspection surface 100a and another arbitrary point on the phosphor surface 31a also always passes through the irradiation focus F of the X-ray source 10 during horizontal movement. In the embodiment of the present invention, for example, a line M (hereinafter referred to as an operation line M) connecting the center point O1 of the desired inspection surface 100a and the center point O2 of the phosphor surface 31a is always passed through the irradiation focus F. The correspondence relationship can be maintained. This is because the printed circuit board 100 and the image detector 30 are not rotated.
[0032]
In order to maintain the correspondence between the desired inspection surface 100a of the printed circuit board 100 and the phosphor surface 31a of the image detector 30, it is necessary to make the movement amount of the image detector 30 larger than the movement amount of the printed circuit board 100. . The ratio of the movement amounts coincides with the ratio of the distance between the points F and O2 along the operating line M and the distance between the points F and O1.
[0033]
Initially, the X-ray irradiation region R extends in the X-axis direction, and the printed circuit board 100 and the image detector 30 are supported at the first position shown in FIG. In this first position, the operation line M coincides with the rotation axis L, and the center point O1 of the printed circuit board 100 and the center point O2 of the phosphor surface 31a of the image detector 30 are on the rotation axis L, that is, the X-ray. It is located directly above the irradiation focus F of the source 10.
[0034]
As shown in FIG. 3, at the first position, the printed circuit board 100 and the image detector 30 are located at the left end (one end) of the X-ray irradiation region R. The X-ray fluoroscopic image is a fluoroscopic image when the printed circuit board 100 is viewed from directly above, and has 16 images of the solder joints 101 and images of the parts 103 (an image including the parts 103 and the solder joints 104). Yes. Here, the two solder joint portions 101 overlap the image of the component 103 and the like.
[0035]
The image treatment device 51 receives position information from the control device 50 and recognizes in advance that the images of the two solder joints 101 overlap with the image of the component 103 or the like at this position. Then, the images of the 14 solder joints 101 excluding the two solder joints 101 are compared with the reference image, and the joining state of these 14 solder joints 101 is detected. Note that the image processing device 51 may use information from detection means for detecting the positions of the printed circuit board 100 and the image detector 30 instead of the position information from the control device 50.
[0036]
Next, the control device 50 controls the moving mechanisms 21 and 22 to move the printed circuit board 100 and the image detector 30 in the X-axis direction as shown in FIG. It moves to the 2nd position of the right end part (the other end part). At this second position, image information based on the X-ray fluoroscopic image is obtained by the image detector 30 in the same manner as described above. In this X-ray fluoroscopic image, as shown in FIG. 3, the image of one solder joint 101 and the image of the component 103 and the like overlap. The image processing device 51 receives position information from the control device 50, and recognizes in advance that one solder joint 101 overlaps an image of the component 103 or the like at this position. Then, the image of the 15 solder joints 101 excluding the one solder joint 101 is compared with the reference image, and the joining state of these 15 solder joints 101 is detected.
[0037]
There may be a case where a complete tomographic image of the desired inspection surface 100a cannot be obtained only by the X-ray images at the first and second positions. For example, in the case of the printed circuit board 100, an image of one solder joint portion 101 in the third row from the left and the third row from the top in FIG. 3 cannot be obtained. In such a case, the control device 50 controls the rotation table 12 to rotate the X-ray source 10 by 90 °. Then, in the X-ray irradiation region R on the first reference plane P1, the major axis of the elliptical shape coincides with the Y-axis direction as shown in FIG. The first and second support mechanisms 21 and 22 move the printed circuit board 100 and the image detector 30 from the first position to the third position in FIG. 3 along the Y-axis direction.
[0038]
At the third position, image information based on the fluoroscopic image is obtained by the image detector 30 in the same manner as described above. In this X-ray fluoroscopic image, as shown in FIG. 3, the images of the two solder joints 101 and the image of the component 103 and the like overlap. The image processing device 51 receives position information from the control device 50 and recognizes in advance that the two solder joints 101 overlap the image of the component 103 or the like at this position. Then, the images of the 14 solder joints 101 excluding the two solder joints 101 are compared with the reference image, and the joining state of these 14 solder joints 101 is detected.
[0039]
At the third position, the images of the two solder joints 101 different from the first and second positions overlap with the image of the component 103 and the like, so that a complete tomographic image of the desired inspection surface 100a is obtained from the images at the three positions. Can be obtained. As is apparent from FIG. 3, in this embodiment, the image at the second position can be omitted. When images at three positions are required, the printed circuit board 100 and the image detector 30 are moved from the first position to the second position and then returned from the second position to the third position without returning to the first position. You may make it move.
[0040]
As described above, since the operation line M connecting the center O1 of the desired inspection surface 100a of the printed circuit board 100 and the center O2 of the phosphor surface 31a of the image detector 30 passes through the irradiation focus F at each position, the desired inspection surface 100a. Tomograms (images of the solder joints 101) appear at substantially the same position on the phosphor surface 31a. On the other hand, since the other surface 100b of the printed circuit board 100 is deviated from the inclination center O1 by the thickness of the printed circuit board 100, the tomographic image of this surface 100b changes according to the position change. Specifically, the image of the component 103 or the like appears at a different position on the phosphor surface 31a as the position changes, and overlaps with the image of the different solder joint portion 101. Therefore, as described above, if the image of the part 103 and the like and the image of the solder joint 101 that overlaps the image at each position are excluded, and the image of the remaining solder joint 101 is selected, the image is mounted on the desired inspection surface 100a. In addition, image information of all the solder joint portions 101 can be obtained, and the joint state can be detected. The image processing apparatus 51 finally displays images of all the joined solder joints 101 on the display device 52. When some of the solder joints 101 are not mounted due to a manufacturing error, the inspector can determine this from the image displayed on the display device 52 and determine that the printed circuit board 100 is defective. Can do. Note that the image processing device 51 may determine the bonding state of the solder bonding portion 101 to determine whether the printed circuit board 100 is good or bad, and notify the determination result by a not-shown notification means.
[0041]
In the above operation, the printed circuit board 100 and the image detector 30 are horizontally moved and temporarily stopped at three positions to obtain image information at each position. Instead, the printed circuit board 100 and the image detector 30 are moved. It is also possible to horizontally move continuously and maintain the exposure state of the photoelectric conversion unit 32 during this continuous movement period. In this case, charges corresponding to the image in the exposure period are stored in the pixels of the photoelectric conversion unit 32. Therefore, the image information output from the photoelectric conversion unit 32 after continuous movement represents an image obtained by substantially superimposing X-ray fluoroscopic images that continuously change on the phosphor surface 31a. Since the image of the solder joint portion 101 on the desired inspection surface 100a appears at substantially the same position on the phosphor surface 31a, it has a strong contrast. On the other hand, the image of the component 103 and the like on the other surface 100b of the substrate 100 changes in the position where it appears on the phosphor surface 31a, and thus appears in a wider area than the actual image with a weak contrast. The image processing device 51 uses the contrast threshold to eliminate intermediate contrast and process the image at a binary logic level. Thereby, an image of only the solder joint portion 101 can be obtained by eliminating the image of the component 103 and the like.
[0042]
In the case of the continuous horizontal movement in the exposure state described above, the phosphor surface 31a moves horizontally in synchronization with the desired inspection surface 100a, and the operation line M must always pass through the irradiation focal point F. When the image is obtained in the pause state described in (1), the operation line M may pass through the irradiation focus F at the stop position, and the movements may not be synchronized.
[0043]
In the above-described operation, the case where the X-ray source 10 is rotated 90 ° has been described. However, the X-ray source 10 may be rotated less than 90 °, or may be rotated 360 ° as shown in FIG. In the case of FIG. 4, two X-ray irradiation regions R arranged in the X axis can be formed, and the moving mechanisms 21 and 22 move the printed circuit board 100 and the image detector 30 from the left end of the left X-ray irradiation region R. If it is moved to the right end of the right X-ray irradiation region R, X-rays can be irradiated from different directions over a wide angle range, and more image information can be obtained. The same applies to the Y-axis direction.
[0044]
In the embodiment of the present invention, if the other surface 100b of the printed circuit board 100 is made to coincide with the first reference plane P1 by the movement of the Z-axis table of the first moving mechanism 21, this surface 100b is set as a desired inspection surface. The joining state of the component 103 can be inspected.
[0045]
In the first embodiment of the present invention, the distance between the phosphor surface 31a of the image detector 30 and the desired inspection surface 100a of the printed circuit board 100 on the operation line M is determined by the movement of the Z-axis table of the second moving mechanism 22. This can change the magnification of the image. In this case, the ratio of the movement amount of the image detector 30 and the printed board 100 also changes.
[0046]
Hereinafter, other embodiments of the present invention will be described. In these other embodiments, components corresponding to those of the first embodiment are denoted by the same reference numerals in the drawing, and detailed description thereof is omitted.
[0047]
FIG. 5 shows an X-ray inspection apparatus according to the second embodiment of the present invention. In the second embodiment of the present invention, the table 13 that supports the X-ray source 10 does not rotate, and the X-ray source 10 only provides a fixed X-ray irradiation region on the first reference plane P1. . The major axis of the ellipse in this X-ray irradiation region extends in the X-axis direction.
[0048]
In the second embodiment, first and second moving mechanisms 41 and 42 (first and second moving means) that translate the printed circuit board 100 and the image detector 30 along reference planes P1 and P2, respectively. Operate with a common motor 40 (drive source). These moving mechanisms 41 and 42 have screw rods 41a and 42a extending in the X-axis direction, and support tables 41b and 42b screwed to the screw rods 41a and 42a, respectively. The printed circuit board 100 is supported on the support table 41b, and the image detector 30 is supported on the support table 42b.
[0049]
The rotation of the motor 40 is transmitted to the screw rods 42 a and 42 b through power transmission means including a gear train 45. That is, the rotation of the motor 40 is directly transmitted to the screw rod 41 a and is transmitted to the screw rod 42 a via the gear train 45. These screw rods 41a and 42a are rotated in the same direction at the same rotation speed. As the screw rods 41a and 41b rotate, the support tables 41b and 42b move in the X-axis direction.
[0050]
In the second embodiment of the present invention, the screw pitch of the screw rod 42a is larger than that of the screw rod 41a, and the amount of movement of the support table 42b (the amount of movement of the image detector 30) is the amount of movement of the support table 41b (printed circuit board). Greater than 100). The ratio of these pitches is equal to the ratio of the distance between the points O2 and F on the operating line M and the distance between O1 and F. Thus, the operating line M always passes through the irradiation focal point F of the X-ray source 10 during the synchronous horizontal movement.
[0051]
In the second embodiment of the present invention, the common motor 40 is used and the operation line M always passes through the irradiation focal point F at the pitch ratio of the screw rods 41a and 42a. An accurate and clear image of the desired inspection surface 100a can be obtained.
[0052]
In addition, you may make the pitch of the screw rods 41a and 42a into the same pitch. In this case, the gear ratio is set so that the ratio of the number of rotations of the screw rods 41a and 42a is equal to the distance between the points O1 and F on the operating line M and the distance between O2 and F. A column 45 is formed. Thereby, the operation line M always passes through the irradiation focal point F of the X-ray source 10.
[0053]
The support tables 41b and 42b may include a basic table and a Z-axis table in order to adjust the height of the printed circuit board 100 and the image detector 30. In this case, the screw rod is screwed onto the foundation table.
Moreover, you may use a belt as a power transmission means between the screw rods 41a and 42a.
[0054]
Next, a third embodiment of the present invention will be described with reference to FIG. In this embodiment, the X-ray source 10 is supported by a rotating table 16 (rotating means) via an inclined table 11 and a linear table 15. The X-ray source 10 is separated from the rotation axis L ′ of the rotation table 16 and rotates around the rotation axis L ′. The rotation axis L ′ is orthogonal to the reference planes P1 and P2. As a result, as shown in FIG. 7, the X-ray irradiation region R on the reference planes P1 and P2 can be changed within an angle range of 360 ° around the rotation axis L ′. Since this operation is almost the same as that of the first embodiment of the present invention, description thereof is omitted.
[0055]
The linear movement table 15 moves the X-ray source 10 along a straight line passing through the rotation axis L ′ (in the radial direction of the rotation table 16 and in the longitudinal direction of the X-ray irradiation region). The positional relationship between the axis L ′ and the X-ray irradiation region R can be changed. This linear motion table 15 may be omitted.
[0056]
Next, a fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, the linear motion table 15 (second moving means) similar to that of the third embodiment is indispensable for obtaining a plurality of pieces of image information. The image detector 30 is supported at a stationary position by a support table 22 ′ (second support means). The center O2 of the phosphor surface 31a of the image detector 30 is preferably on the rotation axis L ′ of the X-ray source 10. The rotation axis L ′ is located at the end of the X-ray irradiation area. The printed circuit board 100 is supported by a moving mechanism 21 ′ similar to that of the first embodiment and is horizontally moved along the reference plane P1. The moving mechanism 21 ′ is not only the first supporting means but also the first moving means.
[0057]
In the fourth embodiment of the present invention, the X-ray source 10 is horizontally moved in the X-axis direction (longitudinal direction of the X-ray irradiation region) by the linear motion table 15, and the printed circuit board 100 is moved by the moving mechanism 21 ′. Synchronously moved in the X-axis direction. The operating line M always passes through the irradiation focal point F during this horizontal movement. In other words, the ratio of the movement amount of the X-ray source 10 and the movement amount of the printed circuit board 100 is equal to the ratio of the distance between the points F and O2 and the distance between the points O1 and O2 on the operation line M.
[0058]
If the X-ray source 10 and the printed circuit board 100 are moved in the Y-axis direction (longitudinal direction of the X-ray irradiation region) in the same manner as described above with the rotating table 16 rotated by 90 °, the irradiation directions are different. A fluoroscopic image is obtained. Further, the X irradiation region and the irradiation direction may be changed by rotating the turntable 16 by 180 °.
[0059]
Also in the fourth embodiment of the present invention, image information can be obtained by two methods in the same manner as in the first embodiment.
In the case of continuous horizontal movement in the exposure state, the phosphor surface 31a moves horizontally in synchronization with the desired inspection surface 100a, and the operation line M must always pass through the irradiation focus F, but stops at a plurality of positions. In the case of obtaining an image in a state, it is sufficient that the operation line M passes through the irradiation focus F at the stop position, and the movements do not have to be synchronized.
[0060]
Further, the printed circuit board 100 is supported at a stationary position by a support table (first support means) (not shown), and the image detector 30 is moved to a second reference by a movement mechanism (which constitutes the second support means and the first movement means) (not shown). You may make it move along the plane P2. In this case, it is preferable that the center point O1 of the printed circuit board 100 is positioned on the rotation axis L ′. In this case, the moving direction of the image detector 30 is opposite to the moving direction of the X-ray source 10.
[0061]
【The invention's effect】
As is clear from the above description, according to the present invention, various X-ray fluoroscopic images can be obtained from different irradiation angles, and an accurate tomographic image on a desired examination surface can be obtained. Moreover, it is not necessary to tilt the inspection object and the image detection means.
[Brief description of the drawings]
FIG. 1 is a schematic view of an X-ray inspection apparatus according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a state in which an inspection object and an image detector are translated in the first embodiment of the present invention.
FIG. 3 is an explanatory diagram showing X-ray fluoroscopic images of the printed circuit board at three positions, changes in the X-ray irradiation area on the first reference plane in the first embodiment of the present invention.
FIG. 4 is an explanatory diagram showing a change in an X-ray irradiation region on a first reference plane in the first embodiment of the present invention.
FIG. 5 is a schematic view of an X-ray inspection apparatus according to a second embodiment of the present invention.
FIG. 6 is a schematic view of an X-ray inspection apparatus according to a third embodiment of the present invention.
FIG. 7 is a diagram showing an X-ray irradiation region on a reference plane in the third embodiment of the present invention.
FIG. 8 is a schematic view of an X-ray inspection apparatus according to a fourth embodiment of the present invention.
[Explanation of symbols]
P1 First reference plane P2 Second reference plane C X-ray central axis F X-ray irradiation focus R X-ray irradiation area L, L ′ on the reference plane X-ray source 12, 16 X-ray source 12, 16 means)
15 linear motion table (second moving means)
21 1st moving mechanism (1st moving means)
22 Second moving mechanism (second moving means)
21 'support table (first support means, first moving means)
22 'support table (second support means)
30 Image detector (image detection means)
31 Image converter 31a Phosphor surface (image receiving surface)
32 Photoelectric conversion unit 40 Common motor (common drive source)
41 1st moving mechanism (1st moving means)
42 Second moving mechanism (second moving means)
41a, 42a Screw rods 41b, 42b Support table 45 Gear train (image transmission means)
100 Printed circuit board (inspection object)
100a Desired inspection surface

Claims (4)

The X-ray is irradiated with a spread, and the central axis of the X-ray is inclined with respect to the first and second reference planes that are parallel to each other, whereby a substantially elliptic X is formed on the first and second reference planes. An X-ray source that forms an irradiation region;
First moving means for supporting the object to be inspected and moving on the first reference plane;
An X-ray image that is arranged opposite to the X-ray source with the inspection object interposed therebetween and that receives an X-ray transmitted through the inspection object and that appears on the image receiving surface is image information. Image detection means for converting into an electrical signal,
Second moving means for moving the image detecting means on the second reference plane in a state where the image receiving surface is parallel to the first and second reference planes;
The first and second moving means are capable of moving the inspection object and the image detecting means along the longitudinal direction of the X-ray irradiation region on the first and second reference planes, and A straight line connecting the center point of the image receiving surface of the detecting means and the center point of the desired inspection surface of the inspection object is moved so as to pass through the irradiation focus of the X-ray source,
The X-ray irradiation area on the first and second reference planes is changed by rotating the X-ray source around a rotation axis that passes through the irradiation focus and is orthogonal to the first and second reference planes. A rotation means,
Within the scope of the X-ray irradiated area has changed by rotating the rotation means, said first, second moving means before Symbol test object, wherein each image detecting means first, second reference plane An X-ray inspection apparatus characterized in that it can be moved two-dimensionally.   The straight line passing through the irradiation focal point of the X-ray source and orthogonal to the first and second reference planes intersects with the first and second reference planes at the end of the X-ray irradiation region. X-ray inspection apparatus described in 1.   The X-ray inspection apparatus according to claim 1, wherein a rotation axis of the X-ray source is orthogonal to the first and second reference planes. The image detecting means has a phosphor surface serving as the image receiving surface, and converts an X-ray image on the phosphor surface into an optical image, and photoelectric conversion that converts the optical image into an electrical signal serving as image information. The X-ray inspection apparatus according to claim 1, further comprising: a section.

Images