X-RAY INSPECTION DEVICE
20170350831 ยท 2017-12-07
Assignee
Inventors
Cpc classification
G01N23/223
PHYSICS
G01N23/18
PHYSICS
International classification
G01N23/223
PHYSICS
Abstract
An X-ray inspecting apparatus, with which X-rays of a broad energy band can be detected while manufacturing costs are suppressed, comprises an X-ray radiation device, a line sensor assembly, and other components. The line sensor assembly has a plurality of detection units and other components. Each detection unit has a scintillator, a detection main body including a plurality of elements disposed thereon, and a ceramic substrate supporting the scintillator and detection main body. In the line sensor assembly, the plurality of detection units etc. are aligned in a forward-backward direction so that the scintillators and the detection main bodies of the detection units etc. are aligned without gaps with the scintillators and detection main bodies of adjacent detection units.
Claims
1. An X-ray inspecting apparatus comprising; an X-ray source configured to radiate X-rays onto goods to be inspected; a detection part configured to detect X-rays of a predetermined energy band and visible light rays of a predetermined wavelength band and to generate a signal; an image production part configured to produce an image on the basis of the signal generated by the detection part; and an inspection part configured to inspect the goods on the basis of the image produced by the image production part; the detection part having a plurality of detection units; the plurality of detection units individually having: a scintillator which extends in a predetermined direction and which emits visible light rays of the predetermined wavelength band by absorbing X-rays of an energy band higher than the predetermined energy band; a detection main body which is disposed on the side of the scintillator that faces the X-ray source and which includes a plurality of elements aligned in the predetermined direction, the plurality of elements being sensitive to X-rays of the predetermined energy band and visible light rays of the predetermined wavelength band and generating the signal; and a base configured to support the scintillator and the detection main body; and the plurality of detection units being aligned along the predetermined direction within the detection part so that the scintillators and the detection main bodies of any of the detection units are aligned without gaps with the scintillators and the detection main bodies of the adjacent detection units.
2. The X-ray inspecting apparatus according to claim 1, wherein the bases are made of a ceramic material.
3. The X-ray inspecting apparatus according to claim 1, wherein the scintillators, the detection main bodies, and the bases are of equal length in the predetermined direction among the plurality of detection units.
4. The X-ray inspecting apparatus according to claim 1, wherein each of the detection main bodies has a fixed part fixed to the base, and an overhanging part protruding from an end of the base; and the plurality of elements are included on the overhanging part.
5. The X-ray inspecting apparatus according to claim 4, wherein the X-ray source is positioned above the plurality of elements; and the detection part further has a cover member which covers the plurality of elements from above and has a lower rate of absorption of the X-rays than the bases.
6. The X-ray inspecting apparatus according to claim 5, wherein the detection part further has a support member configured to support a plurality of the detection units; the support member has a first side face contact part which comes into contact with first side faces of the bases of the plurality of detection units; the cover member has a second side face contact part which comes into contact with second side faces that oppose the first side faces of the bases of the plurality of detection units; and the bases of the plurality of detection units are positioned by the first side face contact part of the support member and by the second side face contact part of the cover member.
7. The X-ray inspecting apparatus according to claim 1, wherein the detection part further has: a support member configured to support the plurality of detection units; and a slitted member disposed between the X-ray source and the plurality of detection units, and having a slit formed therein through which the X-rays pass; and the plurality of detection units are sandwiched between the support member and the slitted member.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
[0039] (1) Overall configuration
[0040] An external view of an X-ray inspecting apparatus according to an embodiment of the present invention is shown in
[0041] The X-ray inspecting apparatus 10 determines whether or not goods which are the articles to be inspected in the X-ray inspecting apparatus 10, contain foreign materials, and when the goods are determined by the X-ray inspecting apparatus 10 to contain foreign materials, the goods are sorted as inferior products by a sorting apparatus 70 (see
[0042] The X-ray inspecting apparatus 10 is configured from a shield box 11, a conveyor 12, an X-ray radiation device 13, a line sensor assembly 14, an LCD monitor 30 with a touch panel function, a control computer 20, etc., as shown in
[0043] (2) Detailed configuration
[0044] (2-1) Shield Box
[0045] The shield box 11 has openings 11a in both sides. The openings 11a are open portions for conveying the goods G in and out. Part of the conveyor 12, the X-ray radiation device 13, the line sensor assembly 14, the control computer 20, etc. are housed within the shield box 11.
[0046] The openings 11a, which serve as openings to convey the goods G in and out, are closed by shielding curtains 16 for suppressing leakage of X-rays to the exterior of the shield box 11. The shielding curtains 16 are molded from rubber containing lead, and are pushed apart by the goods G when the goods G are conveyed in or out.
[0047] In addition to the LCD monitor 30, a key insertion hole and/or a power source switch is also disposed in the upper part of the front face of the shield box 11.
[0048] (2-2) Conveyor
[0049] The conveyor 12 conveys goods G inside the shield box 11, and the conveyor is driven by a conveyor motor 12a shown in
[0050] (2-3) X-Ray Radiation Device
[0051] The X-ray radiation device 13, which is an X-ray source disposed above the central portion of the conveyor 12, radiates X-rays (refer to the symbol XR in
[0052] (2-4) LCD Monitor
[0053] The LCD monitor 30, which is a liquid crystal display that uses a full-dot display, displays X-ray images and/or foreign material determination results. The LCD monitor 30 also has a touch panel function, and also displays a screen prompting, inter alia, input of parameters pertaining to initial settings and/or foreign material inspection.
[0054] (2-5) Control Computer
[0055] The control computer 20 is equipped with a CPU 21, and is also equipped with a ROM 22, a RAM 23, and a hard disk drive (HDD) 25 as main storage parts controlled by the CPU 21, as shown in
[0056] The control computer 20 is also connected with the conveyor motor 12a, the X-ray radiation device 13, the line sensor assembly 14, the LCD monitor 30, the sorting apparatus 70, etc.
[0057] (2-6) Line Sensor Assembly
[0058] The line sensor assembly 14, which is disposed underneath the conveyor 12 as shown in
[0059] The line sensor assembly 14 is configured mainly from first through fourth detection units 41 to 44, a mount 45 made of metal, a cover panel 46 made of carbon, and a slitted panel 47 made of metal.
[0060] (2-6-1) Detection Units
[0061] The first through fourth detection units 41 to 44 are a plurality of units with the same configuration, each of which has a ceramic substrate 51, a detection main body 52, and a scintillator 53.
[0062] The ceramic substrate 51 is a substrate made of a ceramic which supports the detection main body 52 and supports the scintillator 53 via the detection main body 52, and the ceramic substrate has higher hardness and resists deformation better than would a plastic substrate.
[0063] The detection main body 52 is a CMOS image sensor, including a plurality of elements 60 which are light-receiving elements. The plurality of elements 60 are disposed in a straight line in the forward-backward direction (the Y direction). The elements 60 are disposed on the scintillator 53, i.e., on the side of the scintillator 53 that faces the X-ray radiation device 13, as shown in
[0064] The detection main body 52 has a fixed part 52a fixed to an end part of the ceramic substrate 51, and an overhanging part 52b protruding leftward from a left-side end face 51c of the ceramic substrate 51, as shown in
[0065] The plurality of elements 60 are positioned vertically below the X-ray radiation device 13, and X-rays spreading out in a fan shape along a vertical plane from the X-ray radiation device 13, as shown in
[0066] The scintillator 53 is a thin panel-shaped phosphor extending in the forward-backward direction (the Y direction) in which the plurality of elements 60 are aligned, and is bonded to the lower face of the detection main body 52. The scintillator 53 emits visible light rays of a predetermined wavelength band by absorbing X-rays of an energy band higher than the predetermined energy band. The visible light rays emitted from the scintillator 53 are detected by the elements 60 positioned directly above. The elements 60 detect these visible light rays and X-rays of the predetermined energy band, convert the intensities thereof to electric signals, and output these signals as detection signals to the control computer 20.
[0067] The first through fourth detection units 41 to 44 are aligned in the forward-backward direction (the Y direction) in the line sensor assembly 14 so that the detection main body 52 and the scintillator 53 of one of the first through fourth detection units 41 to 44 are aligned without gaps with the detection main body 52 and scintillator 53 of one of the adjacent first through fourth detection units 41 to 44 (for example, the second detection unit 42 adjacent to the first detection unit 41), as shown in
[0068] (2-6-2) Mount
[0069] The metal mount 45 is a support member which supports the first through fourth detection units 41 to 44. The first through fourth detection units 41 to 44, and the hereinafter-described cover panel 46 and slitted panel 47, are placed on the metal mount 45, and are sandwiched by the mount 45 and a fixing panel 48, as shown in
[0070] On the upper part of the mount 45 are formed a groove 45a extending in the forward-backward direction (the Y direction), and step side faces 45b, 45c, as shown in
[0071] (2-6-3) Cover Panel
[0072] The cover panel 46 is a panel-shaped member covering the plurality of elements 60 of the four first through fourth detection units 41 to 44 from above. The cover panel 46, which is made of carbon, has lower X-ray absorptivity than the ceramic substrate 51.
[0073] The cover panel 46 is placed on the mount 45, and the height position of the upper face of the cover panel is level with the position of the upper faces of the ceramic substrates 51 of the first through fourth detection units 41 to 44 (see
[0074] The right-side end face 46c of the main body part 46a of the cover panel 46 is in contact with the left-side end faces 51c of the ceramic substrates 51, and the step side face 45b of the mount 45 described above is in contact with the right-side end faces 51b of the ceramic substrates 51, whereby the first through fourth detection units 41 to 44 are positioned with respect to the left-right direction (the X direction).
[0075] Furthermore, a front side face 46d of the protruding part 46b of the cover panel 46 is in contact with a rear-side end face 51e of the fourth detection unit 44, and the step side face 45c of the mount 45 described above is in contact with the front-side end face 51d of the first detection unit 41 as shown in
[0076] (2-6-4) Slitted Panel
[0077] The slitted panel 47 is a metal plate disposed so as to cover, from above, the cover panel 46 and the ceramic substrates 51 of the left-to-right aligned first through fourth detection units 41 to 44 described above. One slitted panel 47 is placed on top of four ceramic substrates 51 and one cover panel 46, and the slitted panel presses these components down on the upper face of the mount 45. Specifically, the first through fourth detection units 41 to 44 are sandwiched between one mount 45 and one slitted panel 47.
[0078] One long slit 47a extending in the forward-backward direction is formed in the slitted panel 47, directly above the plurality of elements 60 extending continuously in the forward-backward direction (the Y direction) across the first through fourth detection units 41 to 44 (see
[0079] (3) Inspection of Foreign Material Presence/Absence by Control Computer
[0080] (3-1) X-Ray Image Production
[0081] When goods G pass through the X-ray radiation area (refer to the hatched portion in
[0082] (3-2) Determination of Foreign Material Presence/Absence
[0083] From the obtained X-ray image, the foreign material presence/absence inspection part 21b of the control computer 20 determines whether or not the goods G have been contaminated by foreign materials. There are several determination methods, but one example is to set a reference level (a threshold value) in accordance with the general thickness of the detected objects, and to determine that foreign materials have contaminated the goods G when the image is darker than the reference level. As a result of the determinations by the determination methods, if there is determined to be foreign material contamination in the determination of any method, the foreign material presence/absence inspection part 21b determines that foreign materials have contaminated the goods G In this case, the control computer 20 puts an inferior product display on the LCD monitor 30 and sends a sorting command to the sorting apparatus 70.
[0084] (4) Assembly Procedure for Line Sensor Assembly
[0085] Next, some of the assembly steps for the line sensor assembly are described with reference to
[0086] The first detection unit 41 is first placed on the upper face of the mount 45 shown in
[0087] Next, the other detection units are placed in order on the mount 45 so that the second detection unit 42 is aligned with the rear side of the first detection unit 41, the third detection unit 43 is aligned with the rear side of the second detection unit 42, and the fourth detection unit 44 is aligned with the rear side of the third detection unit 43.
[0088] When the first through fourth detection units 41 to 44 are then placed on the mount 45 so that the right-side end faces 51b of the ceramic substrates 51 of the first through fourth detection units 41 to 44 come to be in close proximity to the step side face 45b of the mount 45 as shown in
[0089] After the cover panel 46 has been placed on the mount 45, the cover panel 46 is pushed on the front and right sides. The ceramic substrates 51 of the first through fourth detection units 41 to 44 are thereby pushed on the front and right sides by the cover panel 46. The right-side end faces 51b of the ceramic substrates 51 of the first through fourth detection units 41 to 44 then come to be in contact with the step side face 45b of the mount 45, and the front-side end face 51d of the first detection unit 41 comes to be in contact with the step side face 45c of the mount 45. This is the regular planar positioning of the first through fourth detection units 41 to 44, and in this state, the cover panel 46 is screwed to the mount 45. The screwing may be accomplished by placing the slitted panel 47 on top and then securing both the slitted panel 47 and the cover panel 46 to the mount 45.
[0090] (5) Characteristics of X-Ray Inspecting Apparatus
[0091] (5-1)
[0092] In the X-ray inspecting apparatus 10, because the plurality of elements 60 are disposed on the side of the scintillator 53 that faces the X-ray radiation device 13 in the line sensor assembly 14, X-rays are directly incident on the elements 60, and X-rays of a predetermined energy band are detected by the elements 60. X-rays of an energy band higher than the predetermined energy band are also detected by the elements 60 because these X-rays are converted to visible light rays of a predetermined wavelength band by the scintillator 53. Therefore, the first through fourth detection units 41 to 44 are able to detect X-rays of a broad energy band.
[0093] (5-2)
[0094] In the X-ray inspecting apparatus 10, a configuration is used in which the first through fourth detection units 41 to 44 are aligned in the line sensor assembly 14, but if a configuration were to be used in which all of the elements 60 were included on one unit, the unit would be larger and manufacturing costs would rise for reasons such as assembly being more difficult.
[0095] However, because the X-ray inspecting apparatus 10 employs a configuration in which the first through fourth detection units 41 to 44 are aligned in the forward-backward direction, the yield of each of the first through fourth detection units 41 to 44 is improved, the apparatus is easier to assemble, and manufacturing costs are reduced.
[0096] (5-3)
[0097] In the X-ray inspecting apparatus 10, the first through fourth detection units 41 to 44, in which the plurality of elements 60 are disposed on the sides of the scintillators 53 that face the X-ray radiation device 13, are aligned in the forward-backward direction, which is the longitudinal direction of the detection units, but depending on the manner of alignment, there is a risk that the elements 60 and the scintillators 53 would not be continuous in the borders of adjacent units.
[0098] However, in the X-ray inspecting apparatus 10, the first through fourth detection units 41 to 44 are aligned in the forward-backward direction so that the detection main bodies 52 and the scintillators 53 of the first through fourth detection units 41 to 44 are aligned without gaps with the detection main bodies 52 and the scintillators 53 of the adjacent first through fourth detection units 41 to 44. Therefore, the continuity of the elements 60 and the scintillators 53 is ensured, and there is no problem of X-ray sensitivity being lowered in any section along the forward-backward direction.
[0099] (5-4)
[0100] In the X-ray inspecting apparatus 10, the ceramic substrates 51, which have higher hardness than plastic substrates, are employed as the bases supporting the detection main bodies 52 and the scintillators 53 in the first through fourth detection units 41 to 44 of the line sensor assembly 14. Therefore, there are no situations in which the ceramic substrates 51 deform to compromise the continuity of the elements 60 and the scintillators 53 after the ceramic substrates 51 of adjacent first through fourth detection units 41 to 44 have been brought into contact and the relative positions thereof have been fixed.
[0101] (5-5)
[0102] In the X-ray inspecting apparatus 10, the forward-backward directional length of the ceramic substrate 51, the forward-backward directional length of the detection main body 52, and the forward-backward directional length of the scintillator 53 are equal in each of the first through fourth detection units 41 to 44 of the line sensor assembly 14. The first through fourth detection units 41 to 44 are aligned sequentially so that the front and rear end faces of one ceramic substrate 51 is in contact with the front and rear end faces of the ceramic substrates 51 of adjacent first through fourth detection units 41 to 44, as shown in
[0103] (5-6)
[0104] In the X-ray inspecting apparatus 10, in all of the first through fourth detection units 41 to 44 of the line sensor assembly 14, the elements 60 are disposed on the overhanging parts 52b protruding leftward from the left-side end faces 51c of the ceramic substrates 51. Therefore, even in a line sensor assembly 14 in which the X-ray radiation device 13, the elements 60, and the scintillators 53 are aligned from the top downward, it is possible to achieve a state in which the ceramic substrates 51 are not located between the X-ray radiation device 13 and the elements 60 (see
[0105] Specifically, if the elements 60 were to be included on the fixed parts 52a of the detection main bodies 52 fixed to the ceramic substrates 51, the ceramic substrates 51, the elements 60, and the scintillators 53 would be aligned from the top downward, and X-rays would first pass through the ceramic substrates 51 should X-rays be caused to be incident not from the scintillator 53-side but from the element 60-side. Ceramic substrates generally have higher X-ray absorptivity than plastic substrates, and the output of the X-ray radiation device 13 would need to be increased in order to maintain detection sensitivity.
[0106] In contrast, due to the elements 60 being disposed on and made to receive light on the overhanging parts 52b of the detection main bodies 52 in the X-ray inspecting apparatus 10, it is possible to yield a line sensor assembly 14 that can detect X-rays over a broad energy band with low output, in which X-rays are directly incident on the elements 60 from the X-ray radiation device 13 and X-rays that have passed through the elements 60 are incident on the scintillators 53.
[0107] (5-7)
[0108] In the X-ray inspecting apparatus 10, because the elements 60 are disposed on the overhanging parts 52b of the detection main bodies 52 in the line sensor assembly 14, there is a risk that dust will collect on and adhere to the tops of the elements 60 if no countermeasures are taken. In view of this, in the X-ray inspecting apparatus 10, the elements 60 are covered from above by the cover panel 46, and loss of sensitivity of the elements 60 due to dust is suppressed. Because a carbon cover panel 46 is employed, which has a lower rate of X-ray absorption than the ceramic substrates 51, detection sensitivity can be maintained without increasing the output of the X-ray radiation device 13.
[0109] (5-8)
[0110] In the X-ray inspecting apparatus 10, the mount 45 supporting the first through fourth detection units 41 to 44 and the cover panel 46 covering the plurality of elements 60 from above in the line sensor assembly 14 both have a contact face that comes into contact with the side faces of the ceramic substrates 51 of the first through fourth detection units 41 to 44. Specifically, the step side face 45b of the mount 45 comes into contact with the right-side end faces 51b of the ceramic substrates 51, and the right-side end face 46c of the main body part 46a of the cover panel 46 comes into contact with the left-side end faces 51c of the ceramic substrates 51. The ceramic substrates 51 of the first through fourth detection units 41 to 44 are thereby positioned with respect to the left-right direction (the X direction), whereby the scintillators 53 and the elements 60 of the detection main bodies 52 supported on the ceramic substrates 51 are also accurately positioned. Therefore, in the X-ray inspecting apparatus 10, the scintillators 53 and detection main bodies 52 of two adjacent detection units are aligned without gaps, and the continuity of the elements 60 and the scintillators 53 is ensured.
[0111] (5-9)
[0112] In the line sensor assembly 14 of the X-ray inspecting apparatus 10, the state of X-ray detection stabilizes because X-rays that have passed through the slit 47a in the slitted panel 47 enter the elements 60 and the scintillators 53. The first through fourth detection units 41 to 44 are held by being vertically sandwiched between the slitted panel 47 and the mount 45. Therefore, with the scintillators 53 and the detection main bodies 52 aligned without gaps, the first through fourth detection units 41 to 44 can be maintained as being reliably supported on the mount 45.