JP2001324456A - X-ray cross-sectional plane examination apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray cross-sectional plane examination apparatus which can obtain clear X-ray images using a limited number of parts and a simple structure and without the use of a special optical system. SOLUTION: This apparatus is provided with an X-ray source 2 for irradiating a subject S with X rays, a first rotating means (rotating stage 4) for revolving the specimen, an X ray-optical image conversion means (X rays I.I5) to convert a fluoroscopic image transmitted through the specimen into an optical image, an image pickup means 8 for picking up the optical image, a second rotating means (rotation mechanism 6) for rotating the imaging means synchronized with the first rotation means and an image processing means 9, which composites a plurality of images at the angles of rotation to generate a tomographic image of a subject. The fluoroscopic image is detected by rotating the subject, while the imaging means for obtaining the optical image from transmission X rays is rotated to synchronize the rotation of the subject, thereby obtaining an X-ray image with a higher sharpness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray tomographic plane inspection apparatus for inspecting an X-ray tomographic plane of an inspected object using transmitted X-rays transmitted through the inspected object. Can be applied.

[0002]

2. Description of the Related Art X-ray laminography, X-ray laminography and the like
An X-ray tomography apparatus using transmitted X-rays such as X-ray tomosynthesis is known. X-ray laminography is an X-ray source,
An image of a tomographic plane is detected by moving two of the three elements of the subject and the X-ray detector. FIG. 6 is a diagram showing one configuration of an X-ray tomographic plane inspection apparatus using X-ray laminography. The X-ray tomographic plane inspection apparatus shown in FIG. 6 obtains a tomographic plane image by rotating an X-ray source and an X-ray detector. This is changed by moving the table 27.

In FIG. 6, a scanning X-ray source 20 irradiates a cylindrical anode 21 while rotating an electron beam 28, and transmits an inspection object S while rotating an X-ray beam 29 obtained thereby. The X-ray beam 29 transmitted through the subject S is detected by the CCD camera 25 via the scintillator rotating mechanism 23, and the tomographic plane of the subject is inspected by the transmitted X-ray image obtained by the detection. The scintillator rotation mechanism 23 includes a detection screen 24, a mirror, and a rotation mechanism (not shown), and detects a transmitted X-ray circulating by a rotation operation.

On the other hand, X-ray tomosynthesis detects an image of a tomographic plane by synthesizing a plurality of image data obtained by one imaging. FIG. 7 is a diagram showing one configuration of an X-ray tomographic plane inspection apparatus using X-ray tomosynthesis. The X-ray tomography apparatus shown in FIG. 7 forms an X-ray beam 29 rotated by the X-ray source 20 and
The transmission X-ray beam obtained during one rotation of the 9 is converted into a plurality of X-ray brightness doubling tubes and a plurality of CCD cameras (30 in the figure).
a) to 30h), and performs data processing such as rotation / movement / combination of the image using a plurality of obtained image data to obtain a tomographic plane image.

[0005]

An X-ray tomographic plane inspection apparatus using X-ray laminography has a problem that it is necessary to drive a rotating mechanism for each image data of a tomographic plane to take an image. There is a problem that a high precision is required for the rotation and vertical movement of the lens, and a special optical system such as a scintillator rotation mechanism is required, and the structure becomes complicated. Also, X
An X-ray tomography apparatus using X-ray tomosynthesis requires an X-ray luminance doubler having a small curvature of an X-ray incident surface in order to enhance the accuracy of a tomographic image. In addition, there is a problem that the number of CCD cameras needs to be increased and a large number of parts are required.

On the other hand, it is difficult to use an X-ray luminance doubler with a small degree of curvature or to increase the number of X-ray luminance doublers and CCD cameras in terms of cost and space.
With an X-ray tomography apparatus using X-ray tomosynthesis, it is difficult to obtain a clear X-ray image from a practical viewpoint.
Therefore, the present invention solves the above-mentioned problems of the conventional X-ray tomographic plane inspection apparatus, without using a special optical system,
It is another object of the present invention to provide an X-ray tomographic plane inspection apparatus capable of obtaining a clear X-ray tomographic image with a simple configuration with a small number of parts.

[0007]

SUMMARY OF THE INVENTION The present invention is an apparatus for inspecting a tomographic plane by synthesizing a tomographic plane image by performing image processing on image data obtained from a transmission X-ray image. While detecting the transmitted X-ray image,
By rotating an imaging unit for obtaining an optical image from a line in synchronization with the rotation of the object to be inspected, an X-ray image with high definition is obtained. The X-ray tomographic plane inspection apparatus of the present invention requires a special optical system such as a scintillator rotating mechanism, a large number of X-ray luminance doubling tubes, and a CCD camera by a simple configuration in which the imaging means is rotated synchronously with the object to be inspected. In addition, the height accuracy of the tomographic plane can be improved and a simple structure can be achieved.

An X-ray tomographic plane inspection apparatus according to the present invention comprises: an X-ray source for irradiating an X-ray to an object to be inspected; first rotating means for rotating the object to be inspected; X-ray-optical image conversion means for converting an X-ray image into an optical image, imaging means for capturing an optical image, second rotation means for rotating the imaging means in synchronization with the first rotation means, and each rotation Image processing means for combining a plurality of images at different angles to generate a tomographic image of the object to be inspected.

The first rotating means of the present invention detects a transmission X-ray image while rotating an object to be inspected, thereby obtaining a plurality of transmission X-ray images at a tomographic position to be inspected. The second rotating means is for obtaining a plurality of optical images having different rotation positions by capturing an optical image obtained from the transmitted X-ray image while rotating the image capturing means. Then, the present invention synchronizes the rotations of the first rotating means and the second rotating means, adjusts the rotational positions of the optical images shifted by the first rotating means, and sets a plurality of positions at a tomographic position to be inspected. The optical images are aligned in the same direction. As a result, a tomographic image at a tomographic position to be inspected can be obtained by performing a combining process such as addition on the plurality of obtained images.

In the present invention, only two rotating means are driven, and a simple structure of synchronously rotating the two rotating means without using a special optical system or a large number of parts is used on the object to be inspected. The rotational position of the transmitted X-ray image at the tomographic position to be inspected and the rotational position of the optical image obtained by the imaging unit can be matched. The synchronous rotation of the first rotating means and the second rotating means may be a step-like operation in which a rotation operation and a stop operation at the same angle are repeated in synchronization. The first rotating means and the second rotating means are stopped after rotating by the same angle, and at this time, an optical image is captured by the imaging means. In this step-like operation,
The angle of each rotation operation can be equal, or can be an arbitrary angle for each rotation position.

[0011] The image processing means can generate a tomographic plane by synthesizing images by adding a plurality of images at each rotation angle. By shifting the image of the tomographic position of the body to be inspected to the same position and adding these images, an image of the tomographic plane of an arbitrary cross section can be obtained.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram for explaining an outline of a configuration example of the X-ray tomography apparatus according to the present invention. The X-ray tomographic plane inspection apparatus 1
A mechanism for rotating the subject S with respect to the X-ray source 2 is provided as a mechanism for changing a position to irradiate a line, and a mechanism for rotating the imaging unit 8 for capturing an optical image while rotating it is provided. .

The X-ray tomographic plane inspection apparatus 1 includes an X-ray source 2, an X-Y stage 3 for supporting the inspection object S movably in the X and Y directions, and an X-Y stage 3 together with the X-Y stage 3. A rotating stage 4 for rotating and moving around a first rotation axis C1,
X-rays I. for outputting a transmitted X-ray image obtained by transmitting the object S as an optical image. I (brightness doubling tube) 5 and X-ray I.I. I
Imaging means 8 (imaging lens 8)
a and the optical imaging camera 8b) and the imaging means 8 are connected to an X-ray I.D.
A rotating mechanism 6 and an adapter 7 for rotating and moving around the second rotation axis C2 with respect to I5; an image processing means 9 for processing image data obtained by the imaging means 8 to generate an image of a tomographic plane; and a monitor 11, rotating stage 4 and rotating mechanism 6
And a controller 10 for synchronizing and rotating them.

The image processing means 9 converts an image signal obtained by the image pickup means 8 into a digital signal to perform image processing, and stores image data obtained every time the rotation mechanism 6 rotates. The image storage unit 9b includes an image synthesizing unit 9b that performs operations such as parallel movement and addition on a plurality of images stored in the image storage unit 9b to form a synthesized image. The control unit 10 includes a rotation stage 4 and a rotation mechanism 6
Are rotated in synchronization with each other, and the rotating stage 4 and the rotating mechanism 6 are rotated according to a predetermined rotating angle.
And rotate them synchronously. Note that the rotation angle may be equal or arbitrary.

The mode of the synchronous rotation can be various modes such as a step-like operation in which a rotation operation and a stop operation at the same angle are repeated in synchronization, and a rotation operation at different timings. If the rotation stage 4 and the rotation mechanism 6 are in the same rotation position when the means captures an image, an arbitrary synchronous rotation mode can be adopted. The rotating stage 4 constitutes first rotating means, the rotating mechanism 6 constitutes second rotating means, and the X-ray I.D. I5 is X-ray-
It constitutes an optical image conversion means.

FIG. 2 is a schematic diagram for explaining formation of a transmission X-ray image by rotation of the object to be inspected. An X-ray beam 12 is emitted from a fixed X-ray source 2 toward a subject S arranged on a rotary stage 4. The transmitted X-rays that have transmitted through the subject S are X-ray I.I. An X-ray image 5A is formed by entering the input surface 5a of I5. X-ray I. I5 converts the X-ray image 5A into an optical image 5B and outputs it. The irradiation angle and the beam opening of the X-ray beam 12 are desirably such that the X-ray beam 12 transmits at least through the entire inspection object S.
I5 is desirably large enough to receive transmitted X-rays.

In the above configuration, the X-ray source 2, the X and Y stages 3 and the rotary stage 4, and the X-ray I.D. I5, rotating mechanism 6
Since the arrangement position of the imaging means 8 is fixed,
Irradiated X-rays emitted from the X-ray source 2 always pass through the subject S under the same conditions, and the X-rays I.I. Detected at I5. Therefore, when the inspection object S is rotated by the rotation stage 4, the rotational X-ray I.D. The rotation positions of the X-ray image detected at I5 and the formed optical image correspond one-to-one with the rotation position of the rotary stage 4. On the other hand, the tomographic plane of the subject S is X-ray I.O. At I5, the displacement is detected in the plane direction. Inspection object S
Has a distribution in the thickness direction, the distribution in the thickness direction appears as a distribution in the lateral direction in the transmission X-ray image and the optical image. For example, when the inspection object S has a distribution in the thickness direction of an upper layer Su (indicated by F in the figure) and a lower layer Sd (indicated by K in the figure), the X-ray I.D. The transmission X-ray image and the optical image formed in I5 are formed as images in which the F image of the upper layer Su and the K image of the lower layer Sd are arranged in the horizontal direction.

Here, when the test object S is rotated around the first rotation axis C1, the X-ray I.D. Transmission X formed in I5
The line image and the optical image also rotate. At this time, each rotation image of the transmission X-ray image and the optical image rotates around a predetermined tomographic plane of the subject S. Which tomographic plane becomes the center of rotation depends on the X-ray source 2, the subject S, and the X-ray I.D. Determined from the arrangement relationship of I5, the image of the upper or lower tomographic plane is formed around the image of the central tomographic plane at a position corresponding to each rotation angle. X
The line tomographic plane inspection apparatus utilizes the fact that a tomographic image is formed laterally shifted on the same plane, and superimposes the image of the tomographic plane to be inspected as the same rotational position, thereby providing a clear inspection object. Get the fault plane.

In the superposition of the rotated optical images, since the image at the center position is an image rotated in synchronization with the rotation of the subject S, the X-ray I.D. If the optical images formed on I5 are superimposed at the same rotational position, an accurate superimposed image cannot be obtained due to a displacement in the rotational direction. Therefore, the X-ray tomographic plane inspection apparatus of the present invention provides an X-ray I.D.
An image pickup means such as a CCD camera for picking up an optical image formed on I5 is rotated in synchronization with the rotation of the inspected object S, whereby the rotational position of each image is adjusted to shift the position in the rotational direction. Eliminate and obtain an accurate superimposed image.

The image processing of the X-ray tomographic plane inspection apparatus according to the present invention will be described with reference to FIG. Note that FIG. 3 shows a case where the test object S is rotated at every 90 degrees around the rotation axis C1, but the rotation angle can be arbitrarily set, and the image obtained by reducing the rotation angle is obtained. By increasing the number of data, a more accurate tomographic plane image can be obtained. Hereinafter, it is assumed that the inspected object S has an upper layer part Su (indicated by the symbol of F) and a lower layer part Sd (indicated by the symbol of K), thereby forming a tomographic image by the X-ray tomographic inspection apparatus of the present invention. Will be described.

FIG. 3 shows an upper layer part Su in the tomogram of the object S to be inspected.
X-ray I.M. The case where it is formed on the rotation center on I5 is shown. When the inspected object S is at the position of 0 degree (the rotational position shown on the left side in the figure is 0 degree), the X-ray I.D. I5 is the transmission X in the direction indicated by FK in the X-ray image 5A.
The lines are detected, and an optical image 5B is formed by X-ray-optical image conversion. At this time, the rotation position of the imaging unit 8 is set to 0 ° by the rotation mechanism 6 and the X-ray I.D. The rotational position is adjusted to the reference position of I5. An optical image formed at I5 is captured at the same rotation angle. The image data 8Au (0 °) indicates image data obtained by imaging.

Hereinafter, the description will be made with reference to the rotational position of the inspection object S from which the image data 8Au is obtained. Inspection object S
Is rotated about the rotation axis C1 by 180 ° (the rotation position shown on the right side in the figure is 180 °), and the X-ray I.I. I5
Detects the transmitted X-ray indicated by the inverted FK in the X-ray image 5A ', and forms an optical image 5B' by X-ray-optical image conversion. At this time, the image pickup means 8 is moved to 18 by the rotation mechanism 6.
0 °, and the rotational position 180 ° is changed to X-ray I.D. The rotational position is adjusted to the reference position of I5. The optical image formed at I5 is imaged at a rotation angle of 180 °.
Image data 8Au (180 °) indicates image data obtained by imaging. The image data 8Au (18) obtained by rotating the image capturing unit 180 by 180 ° and capturing an image.
0 °) is based on the reference image data 8Au (0 °).
°).

Similarly, when the test object S is rotated by 90 ° around the rotation axis C1, the image pickup means 8 is rotated by 90 ° to obtain image data 8Au (90 °). Is rotated 270 ° about the rotation axis C1,
The image data 8Au (2
70 °). Further, although not shown, the image pickup means is also rotated at an angle between the rotation angles of 0 °, 90 °, 180 °, and 270 ° in synchronization with the object to be inspected, so that the rotational position is obtained. To obtain a plurality of image data. Obtained image data 8A
u (0 °),..., 8Au (90 °),.
.., 8Au (270 °),... To form a composite image 8Bu. Thereby, the image (for example, K) other than the layer other than the target (for example, the lower part Sd) is blurred and disappears, and the tomographic plane in which the image (for example, F) of the target layer (for example, upper part Su) is made visible Obtainable.

Next, a case where another tomographic plane of the object to be inspected is obtained will be described. FIG. 4 is a schematic diagram for explaining image processing for obtaining another tomographic plane of the test object. Hereinafter, a case where the tomographic plane of the lower layer portion Sd of the inspection object S is obtained will be described. The other tomographic plane of the object to be inspected is image data 8Au (0) of the optical image obtained when the tomographic plane of the upper layer part Su is obtained.
°), ..., 8Au (90 °), ..., 8Au (180 °),
, 8Au (270 °),..., And can be obtained by moving the image data in parallel and adding the processed image data.

The image data 8Au (0 °),..., 8Au (9
0 °),..., 8Au (180 °),.
°) are moved in parallel, so that K of the lower layer portion Sd to be inspected this time is positioned at the same position. The obtained image data 8Ad (0 °),..., 8Ad (90
°), ..., 8Ad (180 °), ..., 8Ad (270
°) are added to form a composite image 8Bd. As a result, an unintended layer (for example, the upper layer S
The image (for example, F) other than u) is blurred and disappears, and a tomographic plane in which the image (for example, K) of the target layer (for example, the lower layer portion Sd) is made visible can be obtained.

The determination of the slice plane as to which of the tomographic planes of the inspected object is the inspection tomographic plane can be performed by superimposing images on the inspected object using the reference points.
FIG. 5 is a diagram for explaining the determination of the slice plane. In FIG. 5A, when an X-ray image is detected from different angles for the detection unit S1 and the reference unit S2, an X-ray image as shown in FIG. 5B is obtained. About this X-ray image,
When the images are synthesized such that the reference portions S2 overlap (see FIG. 5).
(C)), the detection section S1 having the same height as the reference section S2 is added (FIG. 5D). Since the slice plane can be determined by image processing, there is no need to move the object to be inspected, and the slice plane can be determined by only one imaging.

In the above description, an example is shown in which two tomographic planes of the upper layer and the lower layer of the object to be inspected are obtained. However, by changing the amount of parallel movement of the obtained image, an arbitrary depth can be obtained. An X-ray cross-sectional image can be obtained. According to the embodiment of the present invention, an X-ray cross-sectional image can be obtained without using a complicated optical system and a large number of components by a simple configuration in which the imaging unit is simply rotated synchronously with the rotation of the inspection object.

According to the embodiment of the present invention, a clear X-ray cross-sectional image at an arbitrary depth can be obtained by one imaging. According to the embodiment of the present invention, the state of the solder connection can be inspected at an arbitrary height by applying to the mounted component on the board.

[0029]

As described above, according to the X-ray tomographic plane inspection apparatus of the present invention, a special optical system is not used.
Also, a clear X-ray tomographic image can be obtained with a simple configuration with a small number of parts.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining an outline of a configuration example of an X-ray tomographic plane inspection apparatus according to the present invention.

FIG. 2 is a schematic diagram for explaining formation of a transmission X-ray image by rotation of a test object.

FIG. 3 is a schematic diagram illustrating image processing of the X-ray tomographic plane inspection apparatus according to the present invention.

FIG. 4 is a schematic diagram for explaining image processing for obtaining another tomographic plane of a test object.

FIG. 5 is a diagram for explaining how a slice plane is determined.

FIG. 6 is a diagram showing one configuration of an X-ray tomographic plane inspection apparatus using X-ray laminography.

FIG. 7 is a diagram showing one configuration of an X-ray tomographic plane inspection apparatus using X-ray tomosynthesis.

[Explanation of symbols]

1. X-ray tomographic plane inspection apparatus, 2. X-ray source, 3. XY stage, 4. rotary stage, 5. X-ray I. I (brightness intensifier), 5a ... X-ray I.I. I input surface, 5A ... X-ray image, 5B ...
Optical image, 6 ... rotating mechanism, 7 ... adapter, 8 ... imaging means,
8a: imaging lens, 8b: optical imaging camera, 8Au, 8
Ad: image data, 8Bu, 8Bd: composite image, 9: image processing means, 9a: digital processing unit, 9b: image storage unit, 9c: image synthesis unit, 10: control unit, 11: monitor, 12: X-ray Beam, C1, C2: rotation axis, S: test object, Sa: upper layer, Sb: lower layer, S1: detection unit, S
2: Reference part, 20: Scanned X-ray image, 21: Anode, 23: Scintillator rotation mechanism, 24: Detection screen, 25: C
CD camera 26 control unit 27 XYZ table 2
8: electron beam, 29: X-ray beam, 30a to 30h ...
CCD camera.

Claims (3)

[Claims] 1. An X-ray source for irradiating an X-ray to an object to be inspected, first rotating means for rotating the object to be inspected, and a transmitted X-ray image transmitted through the object to be inspected is converted into an optical image. X-ray-optical image conversion means, imaging means for capturing the optical image, second rotation means for rotating the imaging means in synchronization with first rotation means, and a plurality of images at each rotation angle are synthesized. And an image processing means for generating a tomographic image of the object to be inspected. 2. The synchronous rotation of the first rotation means and the second rotation means is a step-like operation in which a rotation operation and a stop operation at the same angle are repeated in synchronization, and the angle of each rotation operation is equiangular or The X-ray tomographic plane inspection apparatus according to claim 1, wherein the angle is an arbitrary angle. 3. An X-ray imaging apparatus according to claim 1, wherein said image processing means generates a tomographic plane of an arbitrary cross section of the inspection object by image synthesis in which a plurality of images at respective rotation angles are translated and added. Line fault plane inspection equipment.