JP2024066806A - Test piece - Google Patents

Abstract

To provide a test piece capable of accurately measuring an outer diameter of a reference material covered by a translucent cover.SOLUTION: A test piece 1 has a reference material 2 fixed to a mount 3, and a translucent upper cover 5 and a translucent lower cover 6 covering the mount 3 and the reference material 2. The upper cover 5 has a flat part 7 larger than the reference material 2 in plan view when viewed from a measurement direction, and a side periphery part 8 continuous to an outer periphery of the flat part 7. The reference material 2 is fixed at a middle position separated from the side periphery part 8. When an outer shape of the reference material is measured by reflected light, the outer shape of the reference material 2 can be accurately measured since light reflected by the reference material transmits through the side periphery part 8, transmits only through the flat part 7 without being deflected, and travels straight (Fig.4).SELECTED DRAWING: Figure 1

Description

Application for exception to loss of novelty has been filed

The present invention relates to a test piece that has a structure in which a standard material is covered with a translucent cover and is used to check the accuracy of foreign object detection by an X-ray inspection device, and in particular to a test piece that allows the external shape of the standard material to be accurately measured from outside the cover.

When using X-ray inspection equipment to detect foreign bodies that have become mixed in with an object under inspection, test pieces are used to check the accuracy of foreign body detection. Specifically, a test piece consisting of a standard substance of a specified material and external shape (shape, outer diameter, etc.) covered with a translucent cover is attached to the object under inspection, and X-ray inspection is performed using the X-ray inspection equipment. The size of detectable foreign bodies can be checked based on how the standard substance appears (is captured) in the X-ray transmission image.

The following Patent Document 1 discloses an invention regarding such a test piece.
This test piece (specimen 10 in Patent Document 1) includes a number of spherical standard substances (sample 11a, etc. in Patent Document 1) having various outer diameters, and a light-transmitting cover (laminate films 13a, 13b in Patent Document 1) that covers these standard substances.

The test piece disclosed in the following Patent Document 1 is a multiple-type having a plurality of reference substances, an example of which is shown in FIG. 9. This test piece 100 comprises a mount 101, a plurality of spherical reference substances 102 attached in a row on the mount 101, an upper cover 104 in which a plurality of hemispherical (or bullet-shaped) containers 103 for covering each of the reference substances 102 are formed in a row, and a flat lower cover 105. The plurality of reference substances 102 have different outer diameters and are arranged in order of the size of the outer diameter. The plurality of containers 103 of the upper cover 104 have inner diameters determined to correspond to the outer diameters of the respective reference substances 102, and are arranged in order of the size of the inner diameters. Then, the mount 101 with the reference materials 102 attached is sandwiched between the upper cover 104 and the lower cover 105 so that each reference material 102 is contained in the container 103 with the corresponding inner diameter, and the outer periphery of the upper cover 104 and the lower cover 105 are heat sealed to integrate them, resulting in a test piece 100 in which multiple reference materials 102 with different outer diameters arranged in order of size are covered by the covers 104 and 105.

There are also single-item test pieces that contain one standard substance, an example of which is shown in Figure 10. As shown in Figure 10, the single-item test piece 200 comprises a mount 201, a spherical standard substance 202 attached to the mount 201, an upper cover 204 in which a hemispherical (or bullet-shaped) container 203 that covers the standard substance 202 is formed, and a flat lower cover 205, with the upper cover 204 and the lower cover 205 being integrated at their outer periphery with the mount 201 in between.

When manufacturing a single-item type test piece 200, as shown in FIG. 11(a), the mount 201 with the reference material 200 attached is placed on the lower cover 205, and the upper cover 204 is placed on the mount 201 so that the reference material 202 is covered by the storage section 203. As shown in FIG. 11(b), the outer periphery of the upper cover 204 and the lower cover 205 are clamped and heat-sealed by the heat-pressing device 300.

Patent Application No. 2020-46342

The test piece is an important tool for checking the accuracy of foreign body detection by an X-ray inspection device. For this reason, the standard substance covered with the cover must be manufactured accurately so that its outer shape has a predetermined shape, outer diameter, etc. For example, if the standard substance is spherical, if the outer diameter of the standard substance displayed on the cover or mount differs from the outer diameter of the standard substance actually covered by the cover, the accuracy of foreign body detection by X-ray transmission images may not be guaranteed. In addition, if the test piece is the above-mentioned multiple type, the outer diameter of each of the multiple standard substances must be correct and each standard substance must be arranged in order of size. Even if the outer diameters of each of the multiple standard substances are correct, if the standard substances are misaligned when arranged on the mount and are not arranged in order of size, the image of the standard substance shown in the X-ray transmission image may be erroneously evaluated, and in this case, the accuracy of foreign body detection by X-ray transmission images may not be guaranteed.

Therefore, to guarantee the accuracy of foreign object detection by X-ray inspection equipment using test pieces, a process is carried out at the time of production to check whether the test pieces have been manufactured as genuine products. In this case, it is common to check by measuring the outer diameter of the standard material from the outside of the cover after the outer periphery of the upper and lower covers that cover the standard material is heat sealed to complete the test piece manufacturing process.

Figure 12 is a diagram showing a method of photographing the standard material 202 with a camera from the side of the upper cover 204 of the test piece 200 and measuring its outer diameter. In Figure 12, a camera (not shown) is arranged above the storage section 203 of the test piece 200 with the shooting direction facing downward, and photographs the standard material 202 below through the storage section 203. Light coming from the periphery of the test piece 200 to the standard material 202 is reflected by the standard material 202 in all directions around it, but the camera captures the light reflected upward as indicated by the vertical arrow in the figure to photograph the standard material 202. At this time, at least a part of the light reflected by the standard material 202 and heading toward the camera is refracted and its path changes when passing through the storage section 203 of the upper cover 204 as indicated by the vertical arrow in the figure, so that the outer diameter of the photographed standard material 202 may be measured as a length DF larger than the actual size. Thus, with the conventional test piece 200, there was a problem in that it was sometimes difficult to accurately measure the outer diameter of the reference material 202 using reflected light.

13 is a diagram showing a method of irradiating light upward from below the lower cover 205 of the test piece 200, photographing the reference material 202 with a camera arranged facing downward above the storage section 203 of the upper cover 204, and measuring its outer diameter. As shown by the upward arrow in FIG. 13(b), the light irradiated upward from below the test piece 200 is photographed by the camera as transmitted light of the test piece 200. At least a part of the transmitted light is refracted and changes its path when passing through the storage section 203 of the upper cover 204 as shown by the arrow in the figure, so that as shown in FIG. 13(a), the inner edge of the ring-shaped shadow S1 generated by the hemispherical storage section 203 of the upper cover 204 and the outer edge of the circular shadow S2 generated by the reference material 202 may overlap with each other, making it difficult to recognize the outer edge or outline of the reference material 202 from the image. Thus, with the conventional test piece 200, there was a problem in that it was sometimes difficult to accurately measure the outer diameter of the reference material 202 using transmitted light.

For this reason, it is conceivable to measure the outer diameter of the standard material during the manufacturing process of the test pieces, rather than after the manufacturing process is completed. For example, it is conceivable to take a direct photograph of the standard material placed on the mount with a camera prior to the process of heat sealing the upper and lower covers. However, this would not only add one manufacturing step, but would also require rearrangement of the manufacturing line to insert an inspection process in the middle of the normal manufacturing process, and would be expected to be extremely cumbersome when handling or transporting the standard material that is in the middle of manufacturing and not covered, as special consideration would be required to prevent loss or mishandling of the standard material and further contamination.

Next, even for properly manufactured test pieces, there are cases where it is required to periodically (e.g., once a year) check whether the standard material of the test piece used in foreign body inspection by the X-ray inspection device has an outer diameter that meets the inspection standards. In such cases, as explained with reference to Figures 12 and 13, the outer diameter of the standard material 202 is measured through the cover using reflected or transmitted light to check whether it meets the standards. However, as described above, light is refracted by the housing portion 203 of the upper cover 204, so even in this case, there is a problem that accurate measurement may be difficult.

The present invention has been made to solve the problems in the conventional technology described above, and aims to provide a test piece that can accurately measure the outer diameter of a reference material covered with a translucent cover.

The test pieces 1, 1a, 21, and 31 described in claim 1 are
A test piece 1, 1a, 21, 31 for confirming the accuracy of foreign object detection by an X-ray inspection device,
A reference material 2 formed into a predetermined shape by a predetermined material;
a light-transmitting cover 5, 6 having a flat portion 7 larger than the reference material 2 provided in a portion covering the reference material 2;
The present invention is characterized by being provided with the following:

The test pieces 1, 1a, 21, and 31 described in claim 2 are the test pieces described in claim 1,
It is characterized in that the size of the flat portion 7 as viewed from a measurement direction intersecting the flat portion 7 is larger than the outer shape of the reference material 2 as viewed from the measurement direction.

The test pieces 1, 21, and 31 described in claim 3 are the test pieces described in claim 2,
The reference material 2 is characterized in that it is fixed at a position spaced apart from a side peripheral portion 8 that is continuous with the outer periphery of the flat portion 7 .

The test pieces 1, 21, and 31 described in claim 4 are the test pieces described in claim 3,
The standard material 2 is characterized in that it is fixed to the center of the side periphery 8 .

The test pieces 1, 21, and 31 described in claim 5 are the test pieces described in claim 4,
The covers 5, 6 are characterized in that they are composed of a flat plate-like first member 6 and a second member 5 in which the side peripheral portion 8 and the flat portion 7 are formed.

The test pieces 1 and 31 described in claim 6 are the test pieces described in claim 5,
The device further includes a base 3 sandwiched between the first member 6 and the second member 5 so as to face the flat portion 7, and the reference material 2 is fixed to the base 3.

The test piece 21 according to the seventh aspect of the present invention is the test piece according to the fifth aspect of the present invention,
The reference material 2 is fixed to the first member 6 so as to face the flat portion 7 .

According to the test piece described in claim 1, a part of the cover that covers the standard substance is provided with a flat portion that is larger than the standard substance, so that the standard substance can be placed inside the outer edge of the flat portion, and therefore the outer shape of the standard substance can be accurately measured.

According to the test piece described in claim 2, the size of the flat portion as viewed from the measurement direction is larger than the outer shape of the standard material as viewed from the measurement direction, so a configuration can be adopted in which the standard material is positioned so that a gap is created between the outer edge of the flat portion and the standard material, allowing the outer shape of the standard material to be accurately measured.

According to the test piece described in claim 3, the standard material is fixed at a position inward away from the side periphery surrounding the flat portion. Therefore, when the external shape of the standard material is measured with reflected light, the light reflected by the standard material passes only through the flat portion without passing through the side periphery and being refracted, so that the external shape of the standard material can be accurately measured. Also, when the external shape of the standard material is measured with transmitted light, the shadow of the standard material and the shadow of the side periphery are separated by the annular light that passes between the standard material and the side periphery and passes through the flat portion, and do not overlap with each other, so that the outer edge or contour of the standard material can be accurately recognized from the image, and the external shape of the standard material can be accurately measured.

According to the test piece described in claim 4, the standard material is fixed in the center of the periphery, so the shadow of the standard material and the shadow of the periphery are separated by the annular light that passes between the standard material and the periphery, is transmitted through the flat portion, and travels straight ahead, and do not overlap each other. Therefore, the outer edge or contour of the standard material can be accurately recognized from the image, and the external shape of the standard material can be accurately measured.

According to the test piece described in claim 5, the effects of the test pieces described in claims 1 to 4 can be easily achieved with a simple configuration with a small number of parts, consisting of a flat first member and a flat second member formed with a side periphery and a flat portion.

According to the test piece described in claim 6, the reference material is fixed to the base, so the reference material can be easily positioned in the center of the periphery by simply sandwiching the base between the first and second members, making it easy to handle the reference material, which is a relatively small part.

According to the test piece described in claim 7, since the standard substance is fixed directly to the first member, a third member for fixing the standard substance between the first and second members is not required, and the test piece can be constructed with a small number of parts. Furthermore, when measuring the outer diameter of the standard substance with transmitted light, the only members through which the light passes are the standard substance and the first and second members, so the contrast between the shadow of the standard substance and the shadow of the side periphery obtained by photographing is stronger, the outer edge or contour of the standard substance becomes clearer, and the outer diameter of the standard substance can be measured more accurately.

FIG. 2 is a cross-sectional view of a test piece according to the first embodiment. 5A to 5C are manufacturing process diagrams of a second member constituting the test piece of the first embodiment. 4A to 4C are manufacturing process diagrams of the test piece of the first embodiment. 4 is a cross-sectional view for explaining measurement of the external shape of a standard substance using reflected light in the test piece of the first embodiment. FIG. 4 is a cross-sectional view for explaining measurement of the external shape of a standard substance using transmitted light in the test piece of the first embodiment. FIG. 10 is a cross-sectional view for explaining measurement of the external shape of a standard substance using transmitted light in a test piece according to a modified example of the first embodiment. FIG. 10A to 10C are diagrams showing a manufacturing process of the test piece of the second embodiment. FIG. 11 is a cross-sectional view of a test piece according to a third embodiment. FIG. 1 is a cross-sectional view of a conventional test piece of a multiple-type. FIG. 1 is a cross-sectional view of a conventional test piece of a single type. FIG. 1 is a manufacturing process diagram of a conventional test piece of a single type. FIG. 1 is a cross-sectional view for explaining measurement of the external shape of a standard substance using reflected light in a conventional test piece that is a single item type. FIG. 1 is a cross-sectional view for explaining measurement of the external shape of a standard material using transmitted light in a conventional test piece of a multiple-type.

Embodiments of the present invention will be described below with reference to Figures 1 to 8. The components of the embodiments shown in the drawings do not necessarily faithfully represent the same configuration as the actual product, but may be represented diagrammatically to be understood in a manner consistent with the description in the specification, and the dimensional ratios of the components do not necessarily match the actual dimensional ratios.

A test piece 1 of the first embodiment will be described with reference to FIGS. 1 to 5. FIG.
The structure of a test piece 1 according to the first embodiment will be described with reference to FIG.
Fig. 1 is a cross-sectional view of a test piece 1 of the first embodiment. This test piece 1 is a single type having one reference material 2. As shown in Fig. 1, this test piece 1 includes a flat mount 3 as a base, a spherical reference material 2 attached to the mount 3 by a fixing means such as an adhesive (not shown), an upper cover 5 as a second member in which a storage section 4 that covers the test piece 1 is formed, and a lower cover 6 as a first member having a substantially flat shape, and the upper cover 5 and the lower cover 6 are integrated at their outer periphery portions sandwiching the outer periphery of the mount 3 to cover the reference material 2.

As shown in FIG. 1, the storage section 4 of the upper cover 5 has a flat section 7 on its upper surface. The flat section 7 is approximately parallel to the flat portion of the lower cover 6 other than the storage section 4, and its shape is circular in a plan view (a downward line of sight parallel to the paper surface in FIG. 1). The storage section 4 of the upper cover 5 has a side periphery 8 formed continuously with the outer periphery of this flat section 7. The side periphery 8 is a portion that connects the flat portion 7 to the flat portion of the lower cover 6 other than the storage section 4. Therefore, the storage section 4 of the upper cover 5 has an overall truncated cone shape.

In FIG. 1, when the standard material 2 is photographed with a camera to measure the outer diameter, the measurement direction (photographing direction) is a direction perpendicular to the plane of the flat portion 7, that is, a downward direction parallel to the paper surface in FIG. 1. When viewed from this measurement direction, the outer diameter and inner diameter of the flat portion 7 are sufficiently larger than the outer diameter of the standard material 2 viewed from the measurement direction. The standard material 2 is fixed at a position approximately at the center of the peripheral side portion 8, which is circumferential. Therefore, the standard material 2 is separated from the peripheral side portion 8, and there is a sufficient gap between the standard material 2 and the peripheral side portion 8. Here, the word "sufficient" in the above explanation means that the peripheral side portion 8 and the standard material 2 are separated enough to be photographed separately when measuring the outer diameter of the standard material 2, which will be described later. The gap between the standard material 2 and the flat portion 7 is also approximately the same as the gap between the standard material 2 and the peripheral side portion 8.

The manufacturing process of the test piece 1 of the first embodiment will be described with reference to FIGS.
As shown in Fig. 2(a), the upper cover 5 made of resin that has been softened by heating using any heating means is molded using a vacuum molding device 10. The vacuum molding device 10 has a molding die 13 consisting of a truncated cone-shaped protruding portion 11 corresponding to the housing portion 4 of the upper cover 5 and a flat plate portion 12 continuous with the protruding portion 11. The inside of the protruding portion 11 is a cavity 14, and a through hole 15 communicating with the cavity 14 is formed on the upper surface of the protruding portion 11. One end of a suction pipe 16 communicating with the cavity 14 is connected to the flat plate portion 12, and the other end of the suction pipe 16 is connected to a suction device (not shown).

As shown in FIG. 2(b), the upper cover 5 made of heated and softened resin is placed over the mold 13 of the vacuum molding device 10. The suction device is operated to generate negative pressure in the cavity 14 as shown by the arrow. The softened upper cover 5 made of resin is attached to the mold 13 by the negative pressure generated in the cavity 14.

As shown in FIG. 2(c), after a predetermined molding time under negative pressure has elapsed, the resin upper cover 5 molded to the shape of the mold 13 is removed from the mold 13 of the vacuum molding device 10.

As shown in FIG. 3(a), the mount 3 with the reference material 2 attached is placed approximately in the center of the upper surface of the lower cover 6, and the upper cover 5 is placed over the mount 3 so that the reference material 2 is covered by the storage section 4. As shown in FIG. 3(b), the outer periphery of the upper cover 5 and the lower cover 6 are clamped and heat sealed with a heat pressing device 300, to obtain the test piece 1 of the first embodiment.

Measurement of the outer diameter of the standard material 2 in the test piece 1 of the first embodiment will be described with reference to FIGS.
Fig. 4 is a diagram showing a method of photographing the standard material 2 with a camera from the side of the upper cover 5 of the test piece 1 to measure its outer diameter. In Fig. 4, a camera (not shown) is arranged above the container 4 of the test piece 1 with the photographing direction facing downward, and photographs the standard material 2 below through the flat part 7 of the upper cover 5. Light coming from the periphery of the test piece 1 to the standard material 2 is reflected by the standard material 2 in all directions around it, but the camera captures the light reflected upward as indicated by the arrow in the figure to photograph the standard material 2. At this time, the light reflected by the standard material 2 toward the camera passes only through the flat part 7 of the upper cover 5 as indicated by the arrow in the figure, so that the outer diameter D of the photographed standard material 2 is the actual size, and the outer diameter D of the standard material 2 can be accurately measured by photographing using reflected light.

Figure 5 shows a method of irradiating light upward from below the lower cover 6 of the test piece 1, photographing the standard material 2 with a camera placed facing downward above the flat part 7 of the upper cover 5, and measuring its outer diameter. As shown by the upward arrow in Figure 5 (b), the light irradiated upward from below the test piece 1 is photographed by the camera as transmitted light through the test piece 1. Here, since the standard material 2 is fixed at a position inside away from the side circumference 8 surrounding the flat part 7, as shown in Figure 5 (a), the shadow S1 of the standard material 2 and the shadow S2 of the side circumference 8 are separated by the annular light L that passes through the gap between the standard material 2 and the side circumference 8 and passes straight through the flat part 7, and do not overlap each other. Therefore, the outer edge or contour of the standard material 2 can be accurately recognized from the image, and the outer diameter of the standard material 2 can be accurately measured.

In addition, according to the test piece 1 of the first embodiment, the reference material 2 is fixed to the mount 3, so that the reference material 2 can be easily positioned in the center of the peripheral portion 8 by simply determining the position of the mount 3 and sandwiching it between the upper cover 5 and the lower cover 6, making it easy to handle even a small reference material 2.

A test piece 1a which is a modified example of the first embodiment will be described with reference to FIG.
As shown in Fig. 6(b), this test piece 1a has the same structure as the test piece 1 of the first embodiment except for one point. The difference is that the reference material 2 is fixed at a position that is off the center of the flat portion 7 or the center of the peripheral side portion 8 of the test piece 1a when viewed from the photographing direction, and the reference material 2 is substantially in contact with the inner surface of the peripheral side portion 8. Note that the same reference numerals as those in the drawings of the first embodiment are used for each component, and the description of the first embodiment is incorporated herein.

As shown in FIG. 6(b), in the modified test piece 1a, light does not pass above the test piece 1a in the area where the reference material 2 contacts the side periphery 8. For this reason, as shown in FIG. 6(a), the shadow S1 of the reference material 2 and the shadow S2 of the side periphery 8 are largely separated by the annular light L that passes through the gap between the reference material 2 and the side periphery 8 and passes through the flat portion 7, but because they contact each other in the area where the reference material 2 contacts the side periphery 8, the outer edge or outline of the reference material 2 becomes slightly unclear in that area.

Thus, the effect of being able to accurately recognize the outer edge or contour of the reference material 2 from the image is somewhat weaker than in the first embodiment, but it is possible to recognize that the shadow S1 of the reference material 2 is circular. Therefore, by setting an appropriate measurement position for the shadow S1, it is possible to measure the outer diameter of the circular shadow S1, unlike the conventional test piece 1 shown in FIG. 13 in which the shadow S1 of the reference material 2 and the shadow S2 of the side periphery 8 overlap all around, and the outer diameter of the reference material 2 can be measured more accurately than with the conventional test piece 1.

A test piece 21 according to the second embodiment will be described with reference to FIG.
Similar to the first embodiment, this test piece 21 is a single type having one reference material 2. However, as can be seen from Fig. 7, the test piece 21 of the second embodiment differs from the first embodiment in that it does not have a mount 3 as a base on which the reference material 2 is attached. The reference material 2 is directly fixed to the upper surface of the lower cover 6 by a fixing means such as an adhesive.

The procedure for manufacturing the test piece 21 of the second embodiment is as follows. As in the first embodiment, an upper cover 5 having a storage section 4 with a flat section 7 is produced by a molding process. As shown in FIG. 7(a), a reference material 2 is fixed at a predetermined position on the lower cover 6, and the upper cover 5 is placed over the lower cover 6 so that the reference material 2 is positioned in the center of the flat section 7 or the side peripheral section 8 when viewed from the shooting direction. Then, as shown in FIG. 7(b), the outer peripheral edges of the upper cover 5 and the lower cover 6 are clamped and heat-sealed by a heat-pressing device 300 to obtain the test piece 21 of the second embodiment.

According to the test piece 21 of the second embodiment, the reference material 2 is fixed directly to the lower cover 6, so that the mount 3 is not necessary and the test piece 21 can be constructed with a small number of parts. Furthermore, when measuring the outer diameter of the reference material 2 with transmitted light, the only components through which the light passes are the reference material 2 and the upper and lower covers 5, 6, so the contrast between the shadow of the reference material 2 obtained by photographing and the shadow of the side periphery 8 is stronger, the outer edge or contour of the reference material 2 becomes clearer, and the outer diameter of the reference material 2 can be measured more accurately.

A test piece 31 according to the third embodiment will be described with reference to FIG.
8 is a cross-sectional view of a test piece 31 of the third embodiment. This test piece 31 is a multiple type having five standard substances 2. This test piece 31 includes a mount 3, five spherical standard substances 2 attached in a row on the mount 3, an upper cover 5 in which five storage sections 4 each having a flat portion 7 covering each standard substance 2 are formed in a row, and a flat lower cover 6. The five standard substances 2 have different outer diameters and are arranged in order of the size of the outer diameter. The five storage sections 4 of the upper cover 5 have inner diameters determined to correspond to the outer diameters of the standard substances 2, and are arranged in order of the size of the inner diameter. Then, the mount 3 to which the standard substances 2 are attached is sandwiched between the upper cover 5 and the lower cover 6 so that each standard substance 2 is stored in the storage section 4 with the corresponding inner diameter, and the outer peripheries of the upper cover 5 and the lower cover 6 are heat-sealed to integrate them, thereby obtaining a test piece 31 having a structure in which five standard substances 2 with different outer diameters arranged in order of size are covered with a cover.

The test piece 31 of the third embodiment can also achieve the same effects as the test piece 1 of the single-item type embodiment described above.

In the above-described embodiment and modified examples, the external shape of the standard material 2 is spherical, but the external shape is not limited to spherical and may be, for example, linear or disc-shaped. If it is linear, the diameter and length can be measured to confirm the type of standard material 2, and if it is disc-shaped, the diameter and thickness can be measured to confirm the type of standard material 2. Furthermore, the material of the standard material 2 is not particularly limited. Furthermore, in the case of a multiple-row type, the number of standard materials 2 is not particularly limited.

Reference Signs List 1, 1a, 21, 31... Test piece 2... Reference material 3... Mount as base 4... Storage section 5... Upper cover as second member 6... Lower cover as first member 7... Flat section 8... Side periphery 10... Vacuum forming device 300... Heat pressing device

Claims (7)

A test piece (1, 1a, 21, 31) for confirming the accuracy of foreign object detection by an X-ray inspection device,
A reference material (2) formed into a predetermined shape using a predetermined material;
a light-transmitting cover (5, 6) having a flat portion (7) larger than the reference material in a portion covering the reference material;
A test piece (1, 1a, 21, 31) comprising: A test piece (1, 1a, 21, 31) as described in claim 1, characterized in that the size of the flat portion as viewed from a measurement direction intersecting the flat portion (7) is larger than the outer shape of the reference material (2) as viewed from the measurement direction. The test piece (1, 21, 31) described in claim 2, characterized in that the standard material (2) is fixed at a position spaced apart from the side peripheral portion (8) that is continuous with the outer periphery of the flat portion (7). A test piece (1, 21, 31) as described in claim 3, characterized in that the reference material (2) is fixed to the center of the peripheral portion (8). The test piece (1, 21, 31) described in claim 4, characterized in that the cover (5, 6) is composed of a flat first member (6) and a second member (5) on which the side peripheral portion (8) and the flat portion (7) are formed. The test piece (1, 21, 31) described in claim 5 further comprises a base (3) sandwiched between the first member (6) and the second member (7) so as to face the flat portion (7), and the reference material (2) is fixed to the base. A test piece (21) as described in claim 5, characterized in that the standard material (2) is fixed to the first member (6) so as to face the flat portion (7).