Test device

Abstract

To miniaturize a test device checking belongings of persons on the basis of collected electromagnetic waves in comparison with a case in which a composite mirror is not used.SOLUTION: A composite mirror 11 has a plurality of concave surface mirrors M0, M1, ..., Mi, Mi+1, .... Curves of the concave surface mirrors M0, M1, ..., Mi, Mi+1, ... passing through an xy plane are represented by respective functions f0(x), f1(x), ..., fi(x), fi+1(x), ... of an independent variable x. A plurality of these functions is a parabola each having a common optical axis I and a focal point P, thus a plurality of concave surface mirrors M forming the composite mirror 11 is a parabolic surface mirror. The concave surface mirror M is all cut off so as not to exceed a thickness t. That is, a y-coordinate of the concave surface mirror M is equal to or more than 0 and equal to or less than t.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a technology for an inspection device that inspects people's belongings based on electromagnetic waves. [Background technology]

[0002] 2. Description of the Related Art As a scanner for inspecting the inside of an object to be inspected, for example, a body scanner for carrying out a body check at an airport or the like is known (see, for example, Patent Document 1).

[0003] Moreover, Patent Document 2 discloses a moving body scanner that detects the position of a moving object (moving body) such as a pedestrian, and switches the propagation direction of the terahertz wave according to the detected position. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-36680 A [Patent Document 2] JP 2019-190951 A Summary of the Invention [Problem to be solved by the invention]

[0005] Techniques for imaging an object using electromagnetic waves include active imaging, in which electromagnetic waves are irradiated onto the object and the transmitted or reflected waves are detected to create an image, and passive imaging, in which electromagnetic waves emitted from the object itself are detected to create an image.

[0006] For example, terahertz waves are electromagnetic waves with frequencies of 100 GHz or more and less than 10 THz. These terahertz waves are used in the above-mentioned active imaging, but because they are emitted in minute amounts from the human body and belongings, they are also used in the above-mentioned passive imaging type walk-through possession inspection device, which detects hidden possessions by using the difference in the amount of radiation.

[0007] In order to receive weak terahertz waves emitted from an object, the receiving system must support a wide bandwidth. However, lenses are not suitable for a wide bandwidth because of their chromatic aberration. In addition, if a single parabolic mirror is used to collect the electromagnetic waves emitted from the entire human body, a considerable depth is required, making the device larger and making it difficult to reduce space. The same is true for active imaging.

[0008] It is an object of the present invention to provide a smaller inspection device for inspecting a person's possessions based on collected electromagnetic waves than would be possible without the composite mirror of the present invention. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the present invention provides, in a first aspect, an inspection device that inspects a person's belongings based on electromagnetic waves collected by a composite mirror consisting of multiple concave mirrors with different focal lengths arranged so that their optical axes and foci overlap.

[0010] According to the inspection device of the first aspect, the inspection device that inspects people's belongings based on collected electromagnetic waves can be made smaller than when the composite mirror according to the present invention is not used.

[0011] In the inspection apparatus of the first aspect, the composite mirror has constants p and c 1 and expressed using an independent variable x indicating the distance from the optical axis. As a second aspect, a configuration may be adopted in which the image sensor has a curved surface obtained by rotating a function curve of JPEG2025036699000002.jpg17143 around the optical axis.

[0012] According to the second aspect of the inspection device, the inspection device that inspects people's belongings based on collected electromagnetic waves can be made small.

[0013] In the inspection device of the first aspect, a configuration in which the concave mirror is a parabolic mirror may be adopted as a third aspect.

[0014] According to the inspection device of the third aspect, parallel light (electromagnetic waves traveling in parallel) from the object to be inspected can be collected at one focal point.

[0015] In the inspection device according to any one of the first to third aspects, a configuration in which the complex mirror is disposed so as not to block the line of movement of the person may be adopted as a fourth aspect.

[0016] According to the inspection device of the fourth aspect, the composite mirror does not impede people's movement line.

[0017] In the inspection device according to any one of the first to fourth aspects, a configuration in which the composite mirror has no gap when viewed from the focal point may be adopted as a fifth aspect.

[0018] According to the inspection device of the fifth aspect, even if the multiple concave mirrors that make up the composite mirror are separated from each other, the reflected light that reaches the focal point is continuous.

[0019] In the inspection device according to any one of the first to fifth aspects, a configuration may be adopted as a sixth aspect in which the electromagnetic waves collected by the composite mirror are guided to a detector by an optical system arranged at the focal point.

[0020] According to the inspection apparatus of the sixth aspect, the optical system guides the electromagnetic wave from the focal point to the detector.

[0021] In the inspection device of the sixth aspect, a configuration in which the optical system is a polygon mirror may be adopted as a seventh aspect.

[0022] According to the inspection device of the seventh aspect, a wide range can be inspected by rotating the optical system, which is a polygon mirror, to scan the inspection object. [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 is a plan view showing an example of an inspection system 9 according to an embodiment of the present invention as viewed from above. [Diagram 2]FIG. 2 is a conceptual diagram illustrating the height direction of the inspection device 1. [Diagram 3] FIG. 2 is a diagram for explaining a parabolic mirror. [Figure 4] FIG. 2 is a diagram showing an example of a composite mirror 11 housed in the inspection device 1. [Diagram 5] 1 is a diagram showing an example of how a composite mirror 11 inspects electromagnetic waves emitted from an inspection target having a length Lz. [Figure 6] 2A and 2B are diagrams showing examples of multiple concave mirrors that make up the composite mirror 11. [Figure 7] FIG. 1 is a diagram showing an example of an inspection device 1 using a polygon mirror in an optical system 12. [Figure 8] FIG. 2 is a diagram showing an example of a composite mirror 11 with no gap when viewed from a focal point P. [Figure 9] FIG. 2 is a diagram showing an example of the shapes of multiple concave mirrors M expressed by one function. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] <Embodiment> <Inspection equipment configuration> Hereinafter, in the figures, the space in which each component is arranged is represented as an XYZ right-handed coordinate space or an xyz right-handed coordinate space. Among the coordinate symbols shown in the figures, a dot in a circle represents an arrow pointing from the back of the paper to the front, and a circle with two intersecting lines represents an arrow pointing from the front of the paper to the back. The direction along the x-axis in space is called the x-axis direction. Among the x-axis directions, the direction in which the x component increases is called the +x direction, and the direction in which the x component decreases is called the -x direction. The y, z, X, Y, and Z components are defined in the same way as the x component.

[0025] FIG. 1 is a plan view showing an example of an inspection system 9 according to an embodiment of the present invention, seen from above. The inspection system 9 is a system for inspecting belongings of a person Q walking along a passageway, and a total of four inspection devices 1 are placed, two on each side of the passageway and in positions that do not block the passageway. This passageway has a width W that extends in the Y-axis direction in an XYZ right-handed coordinate space, and includes the path of movement of person Q when walking. Since all of the four inspection devices 1 are placed in positions that do not block the passageway, they do not block the path of movement of person Q. In FIG. 1, the -Z direction is downward, that is, the direction of gravity, and the X-axis direction is the direction of the width of the passageway.

[0026] Each of the four inspection devices 1 receives (or receives) electromagnetic waves such as terahertz waves emitted in direction D from person Q and his / her belongings. As person Q walks (moves) in the +Y direction, the four inspection devices 1 scan person Q and his / her belongings in the Y-axis direction and the X-axis direction (i.e., the horizontal direction). In addition, the four inspection devices 1 scan person Q and his / her belongings in the Z-axis direction.

[0027] Fig. 2 is a conceptual diagram illustrating the height direction of the inspection device 1. The possessions carried by person Q are present, for example, in the range from above the knees to below the neck, as indicated by the diagonal lines in Fig. 2. Therefore, the inspection device 1 must inspect the range along the Z axis from the position H1 of the knees of person Q walking on the floor surface G with the above-mentioned passage to the position H2 of the neck. The length Lz of this range along the Z axis is, for example, 1200 millimeters.

[0028] FIG. 3 is a diagram for explaining a parabolic mirror. A parabola passing through the origin O is drawn on the xy plane shown in FIG. 3. This parabola is a curve connecting (x, y) when the dependent variable y is expressed as a quadratic function of the independent variable x. Here, the focus P is placed on the y axis, and its y component is p. In this case, the dependent variable y is expressed by the following mathematical formula (1).

[0029]

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[0030] When the range of the incident angle of the electromagnetic waves received at the focal point P by the parabolic mirror exceeds two right angles, i.e., 2π radians, the incident lights will face each other, making it difficult to convert them into collimated light (parallel light) by the optical system and guide them to the detector. Therefore, in general, the y components of the end points E1 and E2 of this parabolic mirror do not exceed p, which is the y component of the focal point P. And, for example, if the y components of the end points E1 and E2 are the same as p, which is the y component of the focal point P, the distance from the end point E1 to the end point E2 is 4p.

[0031] Therefore, when the above-mentioned length Lz is to be inspected with a single parabolic mirror, the depth is Lz / 4. When the above-mentioned length Lz is 1200 mm, the depth of the parabolic mirror is 300 mm. In other words, when the inspection target is, for example, a height of 1200 mm with a single parabolic mirror, the inspection device 1 needs to be large enough to accommodate a parabolic mirror with a depth direction of 300 mm.

[0032] <Configuration of the composite mirror> Fig. 4 is a diagram showing an example of a composite mirror 11 housed in the inspection device 1. Fig. 5 is a diagram showing an example of the composite mirror 11 inspecting electromagnetic waves emitted from an inspection target having a length Lz. As described above, the inspection devices 1 do not block the movement line of the person Q, and the composite mirror 11 is housed in the inspection device 1. Therefore, the composite mirrors 11 shown in Figs. 4 and 5 do not block the movement line of the person Q.

[0033] 4 shows the inside of the inspection device 1 viewed in the -Z direction. The xyz right-handed coordinate space is defined so that the +x direction coincides with the +Z direction, and the -y direction coincides with the direction D in which the electromagnetic wave is received. The inspection device 1 shown in FIG. 4 has a composite mirror 11, an optical system 12, and a detector 13.

[0034] An optical axis I of the composite mirror 11 extends in a direction parallel to the direction D. An optical system 12 is disposed at a focal point P on the optical axis I. This optical system 12 is, for example, a parabolic mirror, and adjusts the electromagnetic waves collected by the composite mirror 11 so that their traveling directions become parallel, and guides them to a detector 13 disposed on the optical axis I. In other words, the inspection device 1 having this optical system 12 is an example of an inspection device in which the electromagnetic waves collected by the composite mirror are guided to a detector by an optical system disposed at the focal point.

[0035] 5, the thickness of the composite mirror 11 in the y-axis direction is thinner than one-fourth of the length Lz. This is because the composite mirror 11 is not a single parabolic mirror, but is formed by arranging multiple concave mirrors with different focal lengths so that their optical axes I and focal points P overlap.

[0036] <Detailed structure of the composite mirror> Fig. 6 is a diagram showing an example of multiple concave mirrors that make up the composite mirror 11. Fig. 6 shows a cross section of the composite mirror 11, which is a rotating body with the y-axis as its center of rotation, cut along an xy plane that includes the y-axis. The y-axis coincides with the optical axis I of the composite mirror 11.

[0037] The composite mirror 11 is made up of a plurality of concave mirrors M 0 , M 1 , …, M i , M i+1 , ... (hereinafter, when there is no need to distinguish between these, they will simply be referred to as concave mirror M).

[0038] The subscript i of each of the multiple concave mirrors M is an integer starting from 0. When the subscript i=0, the concave mirror M 0 contains the origin O. The larger the subscript i, the farther the concave mirror M is from the y-axis.

[0039] Concave mirror M 0, M 1 , …, M i , M i+1 , … that pass through the xy-plane are functions f 0 (x), f 1 (x), …, f i (x), f i+1 (x), … respectively. These multiple functions shown in Fig. 6 are all parabolas having a common optical axis I and a focus P. That is, the multiple concave mirrors M that make up the compound mirror 11 shown in Fig. 6 are mirrors with a curved surface obtained by rotating the above-mentioned parabola around the y-axis, that is, parabolic mirrors.

[0040] y = f i (x) is, in general, a parabola with a y-coordinate on the y-axis being y i (y i ≤ 0) and having a focus P(0, p), and is represented by the following formula (2). Note that y 0 = 0 and i = 0, 1, 2, … (an integer starting from 0).

[0041]

Equation

[0042] Also, all the concave mirrors M are in contact with the straight line indicated by y = t at their respective outer circumferences. And the x-coordinates of the outer circumferences of the multiple concave mirrors M i (i ≥ 0) all coincide with the x-coordinates of the inner circumferences of the adjacent concave mirrors M i+1 on the outside. That is, the compound mirror 11 composed of these multiple concave mirrors M has no gap when viewed from the y-axis direction.

[0043] Here, the point a where y = f i (x) shown by formula (2) is in contact with the straight line indicated by y = ti The x coordinate of i (x i >0). This point a i The perpendicular line drawn from the x-axis to point b i+1 At this point b i+1 is y=f i+1 (x) is the point where it intersects with the x-axis.

[0044] In addition, among the multiple concave mirrors M shown in FIG. 0 has no inner circumference, and the other concave mirrors M i The inner perimeter for (i≧1) has a y coordinate of 0.

[0045] As mentioned above, y=f i (x) is point a i (x i ,t), so by substituting this into equation (2), we get x i p,y i ,t, we obtain the following equation (3).

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[0050] As described above, the four inspection devices 1 provided in the inspection system 9 have a composite mirror 11 in which a plurality of concave mirrors M with different focal lengths are arranged so that their optical axes I and focal points P overlap. In the example shown in Fig. 6, this composite mirror 11 has a thickness t along the optical axis I which is thinner than p, but when it receives electromagnetic waves parallel to the optical axis I, it can collect them at the focal point P regardless of the x coordinate. Therefore, the inspection device 1 according to the present invention is smaller than one that does not use the composite mirror 11.

[0051] The configurations, shapes, sizes, and layouts described in the above embodiments are merely schematic to the extent that the present invention can be understood and practiced. Therefore, the present invention is not limited to the described embodiments, and may be modified in various forms without departing from the scope of the technical ideas set forth in the claims.

[0052] <Modification> The above is a description of the embodiment, but the contents of this embodiment may be modified as follows. In addition, the following modifications may be combined.

[0053] <1> In the above-described embodiment, the optical system 12 is a parabolic mirror that collimates the electromagnetic waves collected by the composite mirror 11 and guides them to the detector 13, but it may have another configuration. For example, the optical system 12 may be a polygon mirror.

[0054] 7 is a diagram showing an example of an inspection device 1 using a polygon mirror in the optical system 12. The optical system 12 shown in FIG. 7 is, for example, a quadrangular pyramid polygon mirror, and scans the composite mirror 11 in the Z-axis direction (x-axis direction) by rotating around an axis J. The electromagnetic wave reflected by the composite mirror 11 is further reflected by the optical system 12, and then further reflected by the parabolic mirror 14 to be guided to the detector 13.

[0055] <2> In the above-described embodiment, the composite mirror 11 is configured so as to have no gaps when viewed from the y-axis direction, but it is sufficient that there are no gaps when viewed from the focal point P.

[0056] Fig. 8 is a diagram showing an example of a composite mirror 11 with no gaps as viewed from focal point P. In the composite mirror 11 shown in Fig. 8, the point where a straight line extending from focal point P to a point on the outer periphery of concave mirror M intersects with the x-axis in the xy plane is a point on the inner periphery of concave mirror M located outside of that concave mirror M. Even with this configuration, electromagnetic waves traveling in the -y direction are reflected by multiple concave mirrors M and collected at focal point P. And, because there are no gaps in composite mirror 11 as viewed from focal point P, the collected electromagnetic waves do not disperse.

[0057] <3> In the above-described embodiment, the curved surface shapes of the multiple concave mirrors M are determined by functions f 0 (x), f 1 (x), …, f i (x), f i+1 (x), ..., but they may also be determined by a common function f(x).

[0058] Fig. 9 is a diagram showing an example of the shape of multiple concave mirrors M expressed by one function. The multiple concave mirrors M shown in Fig. 9 have a shape obtained by cutting one function f(x) along the y-axis direction at intervals of t. All of the multiple concave mirrors M are arranged by translating their bottom ends so that they are in contact with the x-axis.

[0059] In this case, each of the multiple concave mirrors M reflects the electromagnetic wave incident in the -y direction on its inner periphery and directs it to a focal point P(0,p), and also reflects it on its outer periphery and directs it to a point Pt(0,p+t).

[0060] For example, in the composite mirror 11, the x coordinate is x i The point is the concave mirror M i On the outer circumference of the concave mirror M i+1 The inclination of these points on each concave mirror M is expressed as the x coordinate of the above-mentioned y=f(x) x i This coincides with the slope of the tangent line T at the points. Therefore, electromagnetic waves incident in the -y direction at these points are reflected in the direction that would be reflected by a plane mirror placed along the tangent line T.

[0061] Normal N has an x-coordinate of x i 9 is a line perpendicular to the tangent line T at the point. The incident angle and reflection angle shown in FIG. 9 are equal, and both are angles Φ. The complementary angle of twice the angle Φ is the angle θ between the x-axis and the reflection direction described above. Therefore, the relationship between angles Φ and θ is expressed by the following formula (7).

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[0065]

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[0067] In this case, even if the composite mirror 11 has a thickness t, when it receives electromagnetic waves radiated in the -y direction, it can collect them between focus P and focus Pt regardless of the x coordinate. [Explanation of symbols]

[0068] 1...inspection device, 11...composite mirror, 12...optical system, 13...detector, 14...parabolic mirror, 9...inspection system.

Claims

1. An inspection device that inspects people's belongings based on electromagnetic waves collected by multiple concave mirrors with different focal lengths, which are arranged in an xyz coordinate space so that their optical axis coincides with the y axis, the x coordinate of the focus is 0, the y coordinate is p, and the range in the y-axis direction is from 0 to t (where 0<t<p).

2. The concave mirror is a parabolic mirror.

2. The inspection device according to claim 1.

3. The plurality of concave mirrors are arranged so as not to block the path of movement of the person.

3. The inspection device according to claim 1 or 2.

4. The plurality of concave mirrors have no gaps when viewed along the optical axis. The inspection device according to any one of claims 1 to 3.

5. The plurality of concave mirrors have no gaps when viewed from the focal point. The inspection device according to any one of claims 1 to 3.

6. An optical system arranged at the focal point guides the electromagnetic waves collected by the multiple concave mirrors to a detector. The inspection device according to any one of claims 1 to 5.

7. The optical system is a polygon mirror.

7. The inspection apparatus according to claim 6.

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