Inspection apparatus and inspection method

Abstract

To reduce as much as possible the number of a magnetic sensor used for an inspection device for inspecting magnetic characteristics of a test object, for example, presence or absence of foreign substances in the test object.SOLUTION: An inspection device for inspecting magnetic characteristics of a test object includes: a magnetic sensor; a test object table that rotates against the magnetic sensor and on which the test object is placed; and a magnetic shield that surrounds the magnetic sensor and the test object table. A field of view of the magnetic sensor faces a line extending from a center of rotation of the test object table in parallel to the test object table surface and radially.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to an improvement in an inspection apparatus using a magnetic sensor such as an SQUID type and an inspection method thereof.

Background Art

[0002] There is a non-destructive inspection apparatus that uses a magnetic sensor. For example, Patent Document 1 proposes an inspection apparatus using an SQUID type magnetic sensor. By using such a magnetic sensor, fine foreign substances in a subject can be detected. In the inspection apparatus disclosed in Patent Document 1, a magnetic sensor is arranged in a magnetic shield, and a linear subject is passed through the magnetic field of view (sensitivity region) of this magnetic sensor to detect fine foreign substances in the linear subject. Note that Patent Document 2 is referred to as a prior art document related to the present invention.

Prior Art Documents

Patent Documents

[0003] Patent Document 1 Japanese Patent No. 3152074 Patent Document 2 Japanese Patent No. 5145552

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] Subjects that require detection of fine foreign substances are not limited to linear ones. In the example of Patent Document 1, when a linear subject is replaced with a wide one, the width of the magnetic field of view of the magnetic sensor is widened according to the width. Since each magnetic sensor has a narrow field of view, it is necessary to arrange a plurality of magnetic sensors linearly (array of magnetic sensors) to obtain a wide field of view. However, since magnetic sensors are expensive, the number of magnetic sensors constituting the array is desired to be as small as possible.

[0005] Also, when the width of the array is increased to widen the field of view, the number of magnetic sensors to be arranged there increases. As a result, it becomes difficult to make the environments of all the magnetic sensors the same. If the environments are different, differences in the sensitivity of the magnetic sensors may occur. For example, even within a magnetic shield, the influence of an external magnetic field varies depending on the distance from the wall. As a result, the greater the number of magnetic sensors constituting the array, the more likely variations in the sensitivity of each magnetic sensor will occur. From this point as well, it is desirable to minimize the number of magnetic sensors used in the inspection apparatus.

Means for Solving the Problem

[0006] This invention has been made to solve such problems. The first aspect of this invention is defined as follows. That is, An inspection apparatus for inspecting the magnetic characteristics of a subject, a magnetic sensor, a subject table that rotates facing the magnetic sensor and on which the subject is placed, and a magnetic shield that surrounds the magnetic sensor and the subject table, and an inspection apparatus in which the field of view of the magnetic sensor faces a line that is parallel to the surface of the subject table and extends radially from the rotation center of the subject table.

[0007] According to the inspection apparatus of the first aspect defined in this way, the subject is placed on the subject table and rotated. Here, the field of view of the magnetic sensor is made to face a line that is parallel to the surface of the subject table and extends radially from the rotation center of the subject table. For example, assuming the subject table is circular, the field of view of the magnetic sensor is made to face a straight line extending from the center of the circle to the outer periphery. At this time, the length of the magnetic sensor becomes the length of the radius of the circular table. Even when the subject is equal to the diameter of the circular table, by rotating the subject table, the entire subject can be covered by the magnetic sensor with a field of view that covers the radius of the subject table. Thereby, the number of magnetic sensors can be minimized as much as possible. The magnetic characteristics of the subject are inspected by such a magnetic sensor. Here, the magnetic characteristics refer to the magnetic characteristics that characterize the subject, and for example, the amount, size, position, etc. of foreign matter present in the subject correspond thereto. In addition, a change in the composition of the formation material itself of the subject (manifested as a magnetic change) also corresponds thereto.

[0008] The second aspect of this invention is defined as follows. That is, In the inspection apparatus defined in the first aspect, the magnetic sensor is a SQUID type magnetic sensor, The rotation frequency of the subject table is set to a frequency excluding the commercial frequency and frequencies that are integer multiples thereof. According to the inspection apparatus of the second aspect defined in this way, by adopting a SUQUID type magnetic sensor as the magnetic sensor, foreign matter present in the inspection target can be detected with high sensitivity. By rotating the subject table at a predetermined rotation frequency, foreign matter present in the subject passes through the field of view of the magnetic sensor at a predetermined frequency. As a result, it can be understood that what is repeatedly detected at that frequency in the signal detected by the magnetic sensor corresponds to the foreign matter present in the subject. Here, when a SQUID type magnetic sensor is adopted, it is preferable to set the rotation frequency of the subject table within its drive frequency (for example, 50 kHz or less). Note that when the rotation frequency is 10 Hz or less, the sensitivity decreases due to the influence of noise called 1 / f noise. In addition, in the usage environment of the inspection apparatus, there is always a magnetic field at the commercial power frequency (50 Hz or 60 Hz, etc.) and frequencies that are integer multiples thereof caused by its harmonics. That is, by rotating the subject table at a frequency excluding such commercial frequencies and frequencies that are integer multiples thereof, the influence of the external magnetic field can be reliably excluded. Thus, high sensitivity is ensured for the SQUID type magnetic sensor.

[0009] The third aspect of this invention is defined as follows. That is, in the inspection apparatus defined in the first or second aspect, a subject feeder for loading and unloading the subject with respect to the subject table is further provided, A passage window through which the subject feeder passes is formed in the side wall of the magnetic shield. According to the inspection apparatus defined in the third aspect as thus defined, by using the specimen feeder to carry the specimen to the specimen table and carry the specimen out from the specimen table, the inspection throughput is improved.

[0010] The fourth aspect of this invention is defined as follows. That is, in the inspection apparatus defined in the third aspect, one passing window through which the specimen feeder passes is formed in one side wall of the magnetic shield, The specimen feeder is passed through the one passing window. According to the inspection apparatus of the fourth aspect defined as thus defined, since there is only one window formed in the side wall of the magnetic shield, the influence of the external magnetic field is minimized.

[0011] The fifth aspect of this invention is defined as follows. That is, in the inspection apparatus defined in the third or fourth aspect, compared with the passing window of the magnetic shield, the magnetic sensors are unevenly distributed on the upper wall side or the bottom wall side of the magnetic shield, A table moving device for moving the specimen table is further arranged, The table moving device moves the specimen table to a first position and a second position, where the specimen can be transferred between the specimen table and the specimen feeder at the first position, and the specimen table faces the magnetic sensors at the second position. According to the inspection apparatus of the fifth aspect defined as thus defined, compared with the case where the magnetic sensors are arranged at the same level as the passing window, since the magnetic sensors are offset to the upper wall side or the bottom wall side, the distance from the passing window to the magnetic sensors becomes longer. As a result, the influence of the external magnetic field on the magnetic sensors can be suppressed.

[0012] The sixth aspect of this invention is defined as follows. That is, in the inspection apparatus defined in the first to fifth aspects, the magnetic shield is box-shaped, the rotation center of the specimen table passes through the center of gravity of the box-shaped magnetic shield, and the specimen feeder passing through the passing window and the specimen table are arranged on a virtual straight line, The field of view of the magnetic sensor faces a line orthogonal to the virtual line. According to the inspection apparatus of the sixth aspect defined in this way, the influence of an external magnetic field entering through the passage window can be suppressed. That is, because the distance from the passage window to each magnetic sensor becomes large.

[0013] The seventh aspect of this invention is defined as follows. That is, an inspection method using an inspection apparatus including a magnetic sensor, a specimen table, and a magnetic shield surrounding the magnetic sensor and the specimen table, opposing the field of view (inspection region) of the magnetic sensor to a line parallel to and radially extending from the center of rotation of the specimen table on the specimen table surface, An inspection method of rotating the specimen table with a specimen placed thereon so as to face the magnetic sensor. According to the inspection method defined in the seventh aspect defined in this way, the same operation as that of the inspection apparatus defined in the first aspect can be obtained.

[0014] The eighth aspect of this invention defines an inspection method using the inspection apparatus defined in the second aspect, and exhibits the same operation as the inspection apparatus defined in the second aspect. The inspection method of the eighth aspect is defined as follows. That is, in the inspection method defined in the seventh aspect, the magnetic sensor is a SQUID type magnetic sensor, The rotation frequency of the specimen table is set to a frequency excluding the commercial frequency and its integral multiple frequencies.

[0015] The ninth aspect of this invention defines an inspection method using the inspection apparatus defined in the third aspect, and exhibits the same operation as the inspection apparatus defined in the third aspect. The inspection method of the ninth aspect is defined as follows. That is, in the inspection method defined in the seventh or eighth aspect, a specimen feeder for loading and unloading the specimen with respect to the specimen table is further provided, A passage window through which the specimen feeder passes is formed in the side wall of the magnetic shield.

[0016] The tenth aspect of the present invention defines an inspection method using the inspection apparatus defined in the fourth aspect, and has the same effect as the inspection apparatus defined in the fourth aspect. The inspection method of the tenth aspect is defined as follows. That is, in the inspection method defined in the ninth aspect, one passage window through which the specimen feeder passes is formed in one side wall of the magnetic shield, and the specimen feeder is passed through the one passage window.

[0017] The eleventh aspect of the present invention defines an inspection method using the inspection apparatus defined in the fifth aspect, and has the same effect as the inspection apparatus defined in the fifth aspect. The inspection method of the eleventh aspect is defined as follows. That is, in the inspection method defined in the ninth or tenth aspect, the magnetic sensor is unevenly distributed on the upper wall side or the bottom wall side of the magnetic shield as compared with the passage window of the magnetic shield, a table moving device for moving the specimen table is further arranged, and the specimen table is moved to a first position and a second position by the table moving device. Here, at the first position, a specimen can be transferred between the specimen table and the specimen feeder, and at the second position, the specimen table faces the magnetic sensor.

[0018] The twelfth aspect of the present invention defines an inspection method using the inspection apparatus defined in the sixth aspect, and has the same effect as the inspection apparatus defined in the sixth aspect. The inspection method of the twelfth aspect is defined as follows. That is, in the inspection method defined in any one of the seventh to eleventh aspects, the magnetic shield is box-shaped, the rotation center of the specimen table passes through the center of gravity of the box-shaped magnetic shield, and the specimen feeder that has passed through the passage window and the specimen table are arranged on a virtual straight line, and the visual field of the magnetic sensor faces a straight line orthogonal to the virtual straight line.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the inspection apparatus 1 according to the embodiment includes a magnetic sensor array 10, a specimen table 20, a magnetic shield 30, and loading / unloading feeders 41 and 43. The magnetic sensor array 10 is an array in which a plurality of SQUID magnetic sensors (elements) are arranged linearly. This array 10 is fixed by a holder (not shown). In this example, as each magnetic sensor constituting the array 10, a SQUID (superconducting quantum interference device) described in Patent Document 2 proposed by the present inventor is adopted. However, other general-purpose magnetic sensors such as Hall elements and magnetoresistive effect elements can be arbitrarily selected according to the characteristics of the specimen and the inspection environment. The magnetic sensor array 10 arranges magnetic sensors linearly and has the same height for their detection surfaces to obtain a wide field of view. The line serving as the reference for the arrangement may be a straight line or a curve. Furthermore, the magnetic sensors can be arranged in multiple rows.

[0021] The specimen table 20 is not particularly limited as long as it can fix and hold the specimen when it rotates and does not affect the magnetic field. In the example of FIG. 1, made of resinA disk was used as the subject table 20. This subject table 20 is arranged parallel to the arrangement direction of each magnetic sensor constituting the magnetic sensor array 10. In other words, each magnetic sensor is always arranged at an equal distance from the opposing surface of the subject table 20. Thus, the influence of magnetism from the subject placed on the subject table is uniformly detected by each magnetic sensor. By arranging them linearly, each magnetic sensor can be made as close as possible. As a result, the external environment of each magnetic sensor, such as the influence from an external magnetic field on each magnetic sensor, can be made as uniform as possible. In this subject table 20, the magnetic sensor array 10 is configured by arranging each magnetic sensor so as to face a straight line extending from the center of rotation to the outer periphery and facing the side of the loading feeder 41.

[0022] In the above example, the field of view of the magnetic sensor array 10 was set to the same length as the radius of the subject table 20, but it is not limited to this. Depending on the shape and size of the subject, the field of view can be made longer or shorter. Also, the magnetic sensors can be arranged in an arc shape to make the field of view arc-shaped.

[0023] The subject table 20 rotates as the rotation axis 23 rotates. The frequency of this rotation is set to a frequency excluding the commercial frequency and its integral multiple frequencies. The rotation frequency of the subject table 20 is preferably constant, but the rotation frequency can also be changed. In either case, in the electronic control circuit 50, a signal corresponding to the rotation frequency is picked up from the detection signal of the magnetic sensor array 10. The electronic control circuit 50 can identify the position of a foreign object (the cause of the signal) in the subject 3 according to the picked-up signal.

[0024] The magnetic shield 30 can be arbitrarily designed according to the characteristics of the subject and the external environment. In this example, the magnetic shield 30 was formed of a sheet metal of a flat rectangular box-shaped high-permeability material (Permalloy). At the centers of the opposing side walls 34 and 35 of the magnetic shield 30 shown in FIG. 1, a loading window 31 and an unloading window 33 are formed as passing windows. A belt conveyor type loading feeder 41 and an unloading feeder 43 are passed through these windows 31 and 33. The edges of the loading feeder 41 and the unloading feeder 43 face the specimen table 20 and are at the same height.

[0025] Next, the operation of the inspection apparatus 1 in FIG. 1 will be described. First, the rotation frequency of the rotary shaft 23 is determined, and the frequency of, for example, a lock-in amplifier circuit in the electronic control circuit 50 is synchronized and set so that a signal of a frequency corresponding to the rotation frequency is picked up. The specimen 3 is magnetized by a well-known method at a position sufficiently separated from the magnetic shield 30 and placed on the loading feeder 41. The specimen 3 placed on the loading feeder 41 enters the magnetic shield 30 through the loading window 31. At the end of the loading feeder 41, a pick-and-release device (not shown) receives the specimen 3 and places it at the center of the specimen table 20.

[0026] As in this example, the loading feeder 41, the specimen table 20, and the unloading feeder 43 are arranged on the same virtual straight line LH. This facilitates the transfer of the specimen 3. This virtual straight line LH is to connect the transport direction center axes of the loading feeder 41 and the unloading feeder 43 and the rotation center of the specimen table 20. Note that the magnetic sensor array 10 is arranged to face this virtual straight line LH. Also, it is preferable that the rotation center axis of the specimen table 20 coincides with the center of gravity of the magnetic shield 20. Thereby, the magnetic sensor array 10 associated with the specimen table 20 is also arranged near the center of gravity of the magnetic shield. Thus, the influence of the external magnetic field through the wall portion of the magnetic shield 30 is minimized.

[0027] In this example, a disk-shaped specimen 3 is employed. The disk-shaped specimen 3 placed at the center of the specimen table 20 rotates as the specimen table 20 rotates. At this time, the field of view of the magnetic sensor array 10, that is, the arrangement of the magnetic sensors, covers one radius of the specimen table 20. Therefore, if the specimen 3 placed at the center of the specimen table 20 is rotated together with the specimen table 20, all regions of the specimen 3 will have been scanned relative to the field of view of the magnetic sensor array 10.

[0028] As described above, by rotating the specimen 3 at a predetermined rotation frequency, noise in the external magnetic field can be removed. That is, the rotation frequency when a SQUID type magnetic sensor is employed as the magnetic sensor is set within the drive frequency of the SQUID type magnetic sensor and is a frequency excluding commercial frequency and its integral multiple frequencies. Thereby, only magnetic changes caused by foreign objects are detected. In other words, noise can be removed. Also, by repeatedly rotating the specimen 3, signals caused by foreign objects can be repeatedly detected. Thereby, the sensitivity can be increased.

[0029] Note that by shifting the timing of picking up the signal, the two-dimensional spread of foreign objects in the specimen 3 can be specified. By combining the data obtained in this way with the image data of the specimen 3 on the specimen table 20, the absolute position of the foreign objects in the specimen 3 can be specified.

[0030] When the inspection by the magnetic sensor array 10 is completed and the rotation of the specimen table 20 stops, the pick-and-release device moves the specimen 3 on the specimen table 20 to the end of the carry-out feeder 43. Then, the carry-out feeder 43 is operated to carry out the specimen 3 from the magnetic shield 30 through the carry-out window 33. Then, demagnetization is performed by a well-known method.

[0031] FIG. 2 is a schematic diagram showing the configuration of an inspection apparatus 1A according to another embodiment. Note that the same elements as those in FIG. 1 are denoted by the same reference numerals and their description is omitted. In the inspection apparatus 1A of FIG. 2, the magnetic sensor array 10 is arranged to be orthogonal in a plan view to a virtual straight line LH in the transport direction of the object 3 and to face a virtual straight line LV passing through the rotation center of the object table 20. By arranging the magnetic sensor array 10 in this way, the distances between each magnetic sensor constituting the magnetic sensor array and the loading window 31 and the unloading window 33 become maximum. Thus, the influence of an external magnetic field can be suppressed.

[0032] FIG. 3 is a schematic diagram showing the configuration of an inspection apparatus 1B according to another embodiment. Note that the same reference numerals are given to the same elements as in FIG. 1 and the description thereof is omitted. In this inspection apparatus 1B, a window (loading / unloading window 35) is provided only in one side wall 34 of the magnetic shield 30, and a loading / unloading feeder 45 passes through this loading / unloading window 35. The object 3 is loaded onto the object table 20 and then unloaded from the object table 20 by this loading / unloading feeder 45. By thus limiting the window provided in the magnetic shield 30, the influence of an external magnetic field can be suppressed. Thus, the inspection sensitivity is improved.

[0033] FIG. 4 is a schematic diagram showing the configuration of an inspection apparatus 1C according to another embodiment. Note that the same reference numerals are given to the same elements as in FIG. 1 and the description thereof is omitted. In this example, the magnetic sensor array 10 is displaced toward the upper wall 37 side of the magnetic shield 30. Thereby, the influence of an external magnetic field from the loading window 31 and the unloading window 33 can be suppressed. Note that the object table 20 is moved up and down by a lifter 25 as a table moving device. When the object table 20 is at the lower first position, the object is transferred between the loading feeder 41 and the unloading feeder 43. When the object table 20 is at the upper second position, the object 3 is opposed to the magnetic sensor array 10. In the example of FIG. 4, compared with the example of FIG. 1, the magnetic sensor array 10 is unevenly distributed vertically upward. However, from the viewpoint of separating the magnetic sensor array 10 further from the loading window 31 and the unloading window 33, the magnetic sensor array 10 may be unevenly distributed in the vertical direction toward the bottom wall 38 side. Furthermore, it may be unevenly distributed in the diagonally up and down direction from the position of the magnetic sensor array in the example of FIG. 1.

[0034] The present invention is not limited to the description of the embodiments and examples of the above invention. Various modifications are also included in the present invention within the scope that can be easily conceived by those skilled in the art without departing from the description of the claims.

Explanation of Reference Numerals

[0035] 1, 1A, 1B, 1C inspection device 3 subject 20 subject table 30 magnetic shield 31, 33, 35 window 34, 35 side wall 37 upper wall 38 bottom wall

Claims

1. An inspection device for inspecting the magnetic characteristics of a subject, comprising: a magnetic sensor; a subject table that rotates facing the magnetic sensor and on which the subject is placed; and a magnetic shield that surrounds the magnetic sensor and the subject table, wherein in the inspection device, the field of view of the magnetic sensor faces a line that is parallel to the surface of the subject table and extends radially from the rotation center of the subject table. The inspection device further comprises a subject feeder for loading the subject onto the subject table and unloading the subject from the subject table. A passage window through which the subject feeder passes is formed in a side wall of the magnetic shield. The magnetic shield is box-shaped, the rotation center of the subject table passes through the center of gravity of the box-shaped magnetic shield, and the subject feeder that has passed through the passage window and the subject table are arranged on a virtual straight line. The inspection device, wherein the field of view of the magnetic sensor faces a line orthogonal to the virtual straight line.

2. An inspection device for inspecting the magnetic characteristics of a subject, comprising: a magnetic sensor; a subject table that rotates facing the magnetic sensor and on which the subject is fixedly held; and a magnetic shield that surrounds the magnetic sensor and the subject table, wherein in the inspection device, the field of view of the magnetic sensor faces a line that is parallel to the surface of the subject table and extends radially from the rotation center of the subject table. The magnetic sensor is a SQUID type magnetic sensor. The rotation frequency of the subject table is more than 10 Hz. The inspection device further comprises an electronic control circuit for picking up a detection signal of the SQUID type magnetic sensor, and the electronic control circuit comprises a lock-in amplifier circuit that is synchronized and set so as to pick up the detection signal at a frequency corresponding to the rotation frequency of the subject table.

3. The inspection device according to claim 2, wherein the rotation frequency of the subject table is 50 kHz or less.

4. The inspection device according to claim 2 or 3, wherein the rotation frequency of the subject table is changed.

5. The inspection device according to any one of claims 2 to 4, wherein the rotation frequency of the subject table is a frequency excluding commercial frequency and its integral multiple frequencies.

6. The inspection device further comprises a subject feeder for loading the subject onto the subject table and unloading the subject from the subject table. The inspection apparatus according to any one of claims 2 to 5, wherein a passage window through which the specimen feeder passes is formed in a side wall of the magnetic shield.

7. One passage window through which the specimen feeder passes is formed in one side wall of the magnetic shield, The inspection apparatus according to claim 6, wherein the specimen feeder is passed through the one passage window.

8. Compared with the passage window of the magnetic shield, the magnetic sensor is unevenly distributed on the upper wall side or the bottom wall side of the magnetic shield, A table moving device for moving the specimen table is further arranged, The table moving device moves the specimen table to a first position and a second position, where a specimen can be transferred between the specimen table and the specimen feeder at the first position, and the specimen table faces the magnetic sensor at the second position. The inspection apparatus according to claim 6 or 7.

9. The magnetic shield is box-shaped, the rotation center of the specimen table passes through the center of gravity of the box-shaped magnetic shield, the specimen feeder passing through the passage window and the specimen table are arranged on a virtual straight line, The inspection apparatus according to any one of claims 6 to 8, wherein the field of view of the magnetic sensor faces a straight line orthogonal to the virtual straight line.

10. An inspection method using an inspection apparatus including a magnetic sensor, a specimen table, and a magnetic shield surrounding the magnetic sensor and the specimen table, The field of view (inspection area) of the magnetic sensor is opposed to a straight line parallel to the specimen table surface and radially extending from the rotation center of the specimen table, In the inspection method, the specimen table with the specimen thereon is rotated to face the magnetic sensor. The inspection method further includes a specimen feeder for loading and unloading the specimen with respect to the specimen table, A passage window through which the specimen feeder passes is formed in a side wall of the magnetic shield, The magnetic shield is box-shaped, the rotation center of the specimen table passes through the center of gravity of the box-shaped magnetic shield, the specimen feeder passing through the passage window and the specimen table are arranged on a virtual straight line, The field of view of the magnetic sensor faces a straight line orthogonal to the virtual straight line.

11. An inspection method using an inspection apparatus including a magnetic sensor, a specimen table, and a magnetic shield surrounding the magnetic sensor and the specimen table, The visual field (inspection area) of the magnetic sensor is made to face a straight line that is parallel to the surface of the subject table and extends radially from the rotation center of the subject table. In an inspection method of rotating the subject table, which holds the subject fixed, so as to face the magnetic sensor. The magnetic sensor is a SQUID type magnetic sensor. The rotation frequency of the subject table is set to be more than 10 Hz. An electronic control circuit for picking up the detection signal of the SQUID type magnetic sensor is further provided. The electronic control circuit includes a lock-in amplifier circuit, and the lock-in amplifier circuit picks up the detection signal having a frequency corresponding to the rotation frequency of the subject table. An inspection method.

12. The inspection method according to claim 11, wherein the rotation frequency of the subject table is 50 kHz or less.

13. The inspection method according to claim 11 or 12, wherein the rotation frequency of the subject table is changed.

14. The inspection method according to any one of claims 11 to 13, wherein the rotation frequency of the subject table is a frequency excluding the commercial frequency and frequencies that are integer multiples thereof.

15. The inspection method according to any one of claims 11 to 14, further comprising a subject feeder for loading and unloading the subject with respect to the subject table, wherein a passage window through which the subject feeder passes is formed in a side wall of the magnetic shield.

16. One passage window through which the subject feeder passes is formed in one side wall of the magnetic shield, and the subject feeder is passed through the one passage window. The inspection method according to claim 15.

17. Compared with the passage window of the magnetic shield, the magnetic sensor is unevenly distributed on the upper wall side or the bottom wall side of the magnetic shield, and a table moving device for moving the subject table is further arranged, wherein the table moving device moves the subject table to a first position and a second position. Here, at the first position, the subject can be transferred between the subject table and the subject feeder, and at the second position, the subject table faces the magnetic sensor. The inspection method according to claim 15 or 16.

18. The magnetic shield is box-shaped, the rotation center of the subject table passes through the center of gravity of the box-shaped magnetic shield, and the subject feeder that has passed through the passage window and the subject table are arranged on a virtual straight line. The inspection method according to claim 15, wherein the field of view of the magnetic sensor faces a line orthogonal to the virtual line.

19. An inspection apparatus for inspecting the magnetic characteristics of a subject, comprising: a magnetic sensor; a subject table that rotates facing the magnetic sensor and on which the subject is fixedly held; and a magnetic shield surrounding the magnetic sensor and the subject table, in the inspection apparatus, the field of view of the magnetic sensor faces a line that is parallel to the surface of the subject table and radially extends from the center of rotation of the subject table. The magnetic sensor is a SQUID type magnetic sensor. The inspection apparatus further includes an electronic control circuit that picks up the detection signal of the SQUID type magnetic sensor, and the electronic control circuit includes a lock-in amplifier circuit that is synchronized and set so that the detection signal of a frequency corresponding to the rotation frequency of the subject table is picked up.

20. An inspection method using an inspection apparatus including a magnetic sensor, a subject table, and a magnetic shield surrounding the magnetic sensor and the subject table, wherein the field of view (inspection region) of the magnetic sensor is made to face a line that is parallel to the surface of the subject table and radially extends from the center of rotation of the subject table, and the subject table on which the subject is fixedly held is rotated facing the magnetic sensor. The magnetic sensor is a SQUID type magnetic sensor. The inspection method further includes an electronic control circuit that picks up the detection signal of the SQUID type magnetic sensor, the electronic control circuit includes a lock-in amplifier circuit, and the lock-in amplifier circuit picks up the detection signal of a frequency corresponding to the rotation frequency of the subject table.

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