JP7408512B2 - Radiation detector and drilling device - Google Patents

Description

The present invention relates to a radiation detector and a drilling device.

Patent Documents 1 and 2 disclose radiation detectors. The radiation detector includes a scintillator, a fiber optic plate, and a solid-state image sensor. A radiation detector converts radiation into visible light using a scintillator. A radiation detector directs visible light from a scintillator to a solid-state imaging device by means of a fiber optic plate. Then, the radiation detector detects the visible light using a solid-state image sensor.

Patent No. 4080873 Patent No. 4070598

In the technical field of radiation detectors, it is desired to improve detection capabilities. One way to improve the detection capability is to increase the size of optical components such as scintillators and fiber optic plates. The optical component is housed in a casing that houses a solid-state imaging device and a circuit board that drives the device. More specifically, some of the optical components are fixed to the housing. A solid-state image sensor is fixed to this optical component. Furthermore, a circuit board is fixed to the solid-state image sensor via electrode pins. The circuit board is fixed to the housing with screws or the like.

When a plurality of components are housed in a casing and each component is individually fixed to the casing, a mechanical load may be generated at the connection points of the components. For example, when a shock or vibration is applied, there will be a difference in movement between the optical component and the circuit board depending on the difference in mass. As a result, a load is generated at the connection point between the optical component and the circuit board. The greater the difference in mass between the optical component and the circuit board, the greater the difference in movement, which tends to increase the load. Therefore, it has been difficult to increase the size of optical components.

Therefore, the present invention provides a radiation detector that allows the size of an optical component to be increased, and a drilling device equipped with the radiation detector.

A radiation detector that is an embodiment of the present invention includes a scintillator that generates light corresponding to received radiation, a fiber optical plate that receives the light generated by the scintillator from a light incident surface and emits it from a light output surface, and an imaging section having a light receiving section that receives light emitted from a surface and a solid-state imaging device that generates an electrical signal corresponding to the received light; a driving circuit that receives an electrical signal from the solid-state imaging device; an imaging section and a driving circuit. a first holding member that holds the position of the imaging unit with respect to the housing, and a second holding member that holds the position of the light emitting surface with respect to the light receiving unit, and a fiber optic plate and the imaging unit. are integrated by a second holding member, and the imaging section is movable with respect to the drive circuit.

In a radiation detector, the fiber optic plate and the imaging section can be considered as an integrated structure. These are integrally held in the housing by the first holding member. On the other hand, the imaging section is movable with respect to the drive circuit. In this way, even if there is a change in relative position between the imaging section, which is integrated with the fiber optic plate, which has a relatively large mass, and the drive circuit, which has a relatively small mass, each can move independently. be. In other words, no load is generated between the imaging section and the drive circuit due to a change in relative position. As a result, it becomes possible to determine the size and mass of the fiber optic plate without being influenced by the characteristics of the drive circuit. Therefore, the scintillator and fiber optical plate, which are optical components, can be made larger.

The radiation detector in one form may further include a fixing member that fixes the drive circuit to the housing. According to this configuration, the drive circuit can be securely fixed.

The radiation detector in one embodiment may further include a flexible substrate that transmits electrical signals from the imaging unit to the drive circuit and has flexibility. According to this configuration, it is possible to realize a configuration in which electrical signals are transmitted from the imaging section to the driving circuit while allowing movement of the driving circuit with respect to the imaging section.

In one form, the fiber optic plate may include a tapered portion provided on the light exit surface side and having a cross-sectional area that gradually becomes smaller along the direction in which the light travels. According to this configuration, the area of the light incidence surface can be increased to increase sensitivity, and the area of the light exit surface can be decreased to reduce the size of the image sensor.

In one form, a cut surface may be provided on the side surface of the fiber optic plate on the light exit surface side. According to this configuration, the fiber optic plate can be suitably arranged in the housing.

In one form, the imaging section may include an element mounting surface on which the solid-state image sensor is mounted, and a frame section that stands up from the element mounting surface. According to this configuration, the solid-state image sensor and the fiber optic plate can be connected while protecting the solid-state image sensor.

In one form, the first holding member may be epoxy resin or silicone rubber. According to this configuration, the fiber optic plate can be reliably held in the housing.

In one form, the second holding member may be made of epoxy resin. According to this configuration, the position of the light emitting surface with respect to the light receiving section can be suitably maintained.

In one form, the area of the light exit surface may be smaller than the area of the light entrance surface. According to this configuration, it is possible to reduce the area of the light exit surface and downsize the image sensor.

A drilling device according to another embodiment of the present invention includes a radiation emitting section that is disposed on a first surface side of a workpiece and irradiates radiation toward the first surface of the workpiece; a radiation detection section that is disposed on a second surface opposite to the first surface of the workpiece and receives radiation emitted from the radiation detection section and transmitted through the workpiece; The radiation detection section includes a movement mechanism that moves the workpiece relatively to the workpiece, and a drilling section that forms a through hole in the workpiece. It has a fiber optical plate that receives light from a light incidence surface and emits light from a light output surface, and a solid-state image sensor that has a light receiving section that receives light emitted from the light output surface and generates an electrical signal corresponding to the received light. An imaging section, a drive circuit that receives electrical signals from the solid-state imaging device, a housing that houses the imaging section and the drive circuit, a first holding member that holds the position of the imaging section with respect to the housing, and a light exit surface for the light receiving section. The fiber optic plate and the imaging section are integrated by the second holding member, and the imaging section is movable with respect to the drive circuit.

This drilling device is equipped with the radiation detector described above. Therefore, the detection accuracy of the drilling position can be improved by using a fiber optic plate that can be made larger. Furthermore, when moving the radiation detection section relative to the workpiece, it is possible to increase the movement speed even though the radiation detector includes large optical components. Therefore, processing speed can be increased.

According to the present invention, there is provided a radiation detector that allows the size of an optical component to be increased, and a drilling device equipped with the radiation detector.

FIG. 1 is a perspective view showing the structure of a radiation detector according to an embodiment. FIG. 2 is a front view showing the structure of the radiation detector according to the embodiment. FIG. 3 is an enlarged view showing the second holding member and coating member included in the radiation detector shown in FIG. FIG. 4 is a perspective view of the fiber optic plate. FIG. 5 is a side view of the fiber optic plate. FIG. 6 is a schematic diagram showing an X-ray drilling apparatus equipped with the radiation detector shown in FIG. 1; FIG. 7 is a perspective view showing the structure of a radiation detector according to a comparative example.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description will be omitted.

As shown in FIGS. 1 and 2, the radiation detector 1 includes a housing 2, an X-ray detection section 3, and a drive circuit 4.

The housing 2 accommodates a part of the X-ray detection section 3 and the drive circuit 4. The housing 2 shields the contents from X-rays. The housing 2 has a substantially rectangular parallelepiped shape and is made of stainless steel. The housing 2 includes a case 21 and a fixing member 22. The case 21 accommodates a part of the X-ray detection section 3 (a solid-state imaging device to be described later) and the drive circuit 4. A fixing member 22 is attached to a first end of the case 21 . A connection terminal 23 is provided at the second end of the case 21 . This connection terminal 23 may be used to transmit and receive electrical signals to and from the drive circuit 4, or may be used to supply power.

The fixing member 22 accommodates another portion of the X-ray detection section 3 (a fiber optic plate 34 described later). The fixing member 22 also holds the fiber optic plate 34 . The fixing member 22 has, for example, a circular through hole 22h in plan view. A fiber optic plate 34 is arranged in the through hole 22h. The thickness of the fixing member 22 may be shorter than the length of the fiber optic plate 34. That is, the light incident surface 34R, which is the first end of the fiber optic plate 34, protrudes from the first end of the fixing member 22. Similarly, a light exit surface 34S, which is a second end of the fiber optic plate 34, protrudes from the second end of the fixing member 22. The second end of the fiber optic plate 34 is placed inside the case 21 described above.

The fixing member 22 is fixed to the case 21. This fixation means that the position of the fixing member 22 does not substantially change with respect to the case 21. In other words, the fixing member 22 and the case 21 may be regarded as an integral body.

The X-ray detection unit 3 includes a package 31 , a circuit board 32 , a solid-state imaging device 33 , a fiber optic plate 34 , a scintillator 35 , and a closing member 36 . Of these, the package 31 , the circuit board 32 , the solid-state imaging device 33 , and the closing member 36 constitute the imaging section 5 . A solid-state image sensor 33 is attached to a package 31 made of a ceramic member. The package 31 has an element mounting surface 31a and a frame portion 31b. The element mounting surface 31a has a region for mounting the solid-state image sensor 33 and a wiring pattern, and the wiring pattern and the solid-state image sensor 33 are electrically connected by bonding wires. A frame portion 31b that stands upright from the element mounting surface 31a is provided at a peripheral portion of the element mounting surface 31a. The height of the frame portion 31b is higher than the solid-state image sensor 33 and higher than the bonding wire. A space surrounded by the element mounting surface 31a and the frame portion 31b is a recess 31S (see FIG. 2) that accommodates the solid-state image sensor 33.

As shown in FIG. 3, the closing member 36 covers the recess 31S. The closing member 36 is fixed to the frame portion 31b of the package 31. The closing member 36 may be a resin tape (for example, Kapton (registered trademark) tape) using a polyimide film. The closing member 36 has an opening 36h formed therein. The opening 36h is for inserting the fiber optic plate 34. According to this closing member 36, it is possible to prevent a coating member 37B, which will be described later, from entering the recess 31S.

Note that the closing member 36 does not need to be a resin tape. For example, a metal plate having sufficient rigidity and blocking visible light may be used as the closing member. As the closing member, an opaque plate-like member made of stainless steel and having a thickness of about 1 mm may be employed. When an opaque plate-like member made of stainless steel is used as the closing member, it is possible to block X-rays and visible light.

The closing member 36 is provided with a coating member 37B. More specifically, the coating member 37B covers the closure member 36. The closing member 36 includes a portion that covers the recess 31S and a portion that covers the frame portion 31b. Coating member 37B is provided on both of these parts. Of these, the coating member 37B provided on the part that covers the frame portion 31b can be said to be provided on the closing member 36, strictly speaking, but in this embodiment, the coating member 37B is provided on the frame portion 31b. It is also said that it is set up. The coating member 37B also covers the boundary between the closure member 36 and the fiber optic plate 34. The coating member 37B may be in contact with the cut surface 34C, which is the surface of the fiber optic plate 34. By filling the space between the closing member 36 and the fiber optic plate 34 with the coating member 37B, the inside of the package 31 (the recess 31S) is sealed. In other words, gas, water vapor, and the like are prevented from flowing in and out between the inside and outside of the package 31. In other words, the coating member 37B prevents moisture from entering the recess 31S from the connecting portion between the closing member 36 and the fiber optic plate 34. The coating member 37B may be made of, for example, epoxy resin. It is desirable that the coating member 37B not enter the recess 31S. According to this configuration, it is possible to suppress damage to the solid-state image sensor 33 and the bonding wire disposed in the recess 31S due to thermal deformation of the coating member 37B.

The solid-state image sensor 33 is fixed to an element mounting surface 31a forming the bottom of the recess 31S. A plurality of electrode pads are provided outside the region of the recess 31S where the solid-state image sensor 33 is fixed. The solid-state image sensor 33 and the electrode pads are connected to each other by the above-described bonding wire. The wiring pattern including these electrode pads is electrically connected to the drive circuit 4 by a flexible substrate 38 connected to the input/output section of the package 31.

The solid-state image sensor 33 is a CMOS image sensor formed on a silicon substrate. The solid-state image sensor 33 includes a light receiving section 33a. The solid-state image sensor 33 includes a plurality of electrode pads that output generated signals. The electrode pads of the solid-state imaging device 33 are electrically connected to the electrode pads on the device mounting surface 31a by bonding wires. The signals generated by the solid-state image sensor 33 are sent to the drive circuit 4 via the electrode pads and bonding wires on the solid-state image sensor 33 side, the electrode pads and wiring patterns on the package 31 side, and the flexible substrate 38 (see FIG. 1). Output.

An epoxy optical adhesive 37A is applied to the light receiving portion 33a of the solid-state image sensor 33, and the light output surface 34S of the fiber optical plate 34 is fixed by this epoxy optical adhesive 37A. The epoxy optical adhesive 37A maintains the position of the solid-state image sensor 33 relative to the fiber optic plate 34. In other words, the epoxy optical adhesive 37A is the second holding member.

Note that the position where the second holding member is provided is not limited to the above-mentioned position as long as the position of the solid-state image sensor 33 with respect to the fiber optic plate 34 can be held. For example, it may be arranged inside the coating member 37B. That is, the second holding member may be provided to fix the closure member 36 and the fiber optic plate 34.

As shown in FIG. 4, the fiber optic plate 34 guides the light generated by the scintillator 35 to the solid-state image sensor 33. Therefore, the fiber optic plate 34 is placed between the scintillator 35 and the solid-state image sensor 33. The fiber optical plate 34 is composed of a core made of a core glass material, a clad core glass made of a clad glass material, and the like.

The fiber optic plate 34 has a light entrance surface 34R and a light exit surface 34S. The light entrance surface 34R of the fiber optic plate 34 is optically connected to the scintillator 35. The light exit surface 34S of the fiber optic plate 34 includes an effective area of the light receiving section 33a of the solid-state image sensor 33 when viewed from the X-ray incident direction. The optical connection includes not only a mode in which the scintillator 35 is in direct contact with the light incidence surface 34R of the fiber optical plate 34, but also a mode in which an optical material is provided between the light incidence surface 34R of the fiber optical plate 34 and the scintillator 35. It may include an aspect in which the image is placed. The light emitting surface 34S of the fiber optic plate 34 is optically connected to the light receiving section 33a of the solid-state image sensor 33 by an epoxy optical adhesive 37A.

The fiber optic plate 34 is held with the light emitting surface 34S optically connected to the light receiving section 33a of the solid-state image sensor 33. More specifically, the fiber optic plate 34 is held on the fixing member 22 by a first holding member 39 . The fiber optic plate 34 includes a held surface 34t, and the held surface 34t faces the inner circumferential surface 22t of the through hole 22h provided in the fixing member 22. Since the outer diameter of the fiber optic plate 34 at the held surface 34t is smaller than the inner diameter of the through hole 22h, a gap is formed between the held surface 34t and the inner peripheral surface 22t.

A first holding member 39 is filled in the gap formed between the held surface 34t and the inner circumferential surface 22t. When the held surface 34t is a circumferential surface, the first holding member 39 has an annular shape when viewed from the X-ray incident direction. The first holding member 39 is made of resin material. For example, the first holding member 39 may be made of silicone rubber. In this case, the first holding member 39 may be considered to undergo significant elastic deformation. This significant elastic deformation may significantly change the position of fiber optic plate 34 relative to fixation member 22. For example, if the central axis of the fiber optic plate 34 and the central axis of the through hole 22h match in the initial state, the distance from the held surface 34t to the inner circumferential surface 22t is the same. On the other hand, if the first holding member 39 is deformed, the distance from the held surface 34t to the inner circumferential surface 22t will be uneven.

The area of the light exit surface 34S is smaller than the area of the light entrance surface 34R. The shape of the fiber optic plate 34 having such a relationship is a tapered shape. The area of the light incident surface 34R of the fiber optic plate 34 is, for example, approximately 310 mm ² . Further, the area of the light exit surface 34S of the fiber optic plate 34 is, for example, approximately 95 mm ² . Therefore, the ratio of the area of the light entrance surface 34R to the area of the light exit surface 34S is 1.0 or more, and is 3.24 as an example.

The shape of the fiber optic plate 34 will be further explained. The fiber optic plate 34 includes an upstream section 34a including a light entrance surface 34R, and a downstream section 34b (tapered section) including a light exit surface 34S. In the examples shown in FIGS. 4 and 5, the upstream portion 34a has a constant width along the X-ray incident direction RA and perpendicular to the X-ray incident direction RA. That is, if the shape of the upstream portion 34a in plan view is circular, the width perpendicular to the X-ray incident direction RA is the diameter.

The width of the downstream portion 34b gradually becomes narrower at a predetermined rate along the X-ray incident direction RA. According to the examples shown in FIGS. 4 and 5, the approximate shape of the downstream portion 34b is a generally tapered shape with a concave tip. When the downstream portion 34b is viewed in cross section in a plane including the X-ray incident direction RA, the outline defining the cross-sectional shape of the downstream portion 34b is a curve. That is, the outer surface of the downstream portion 34b is a curved surface. Further, the downstream portion 34b includes four planes formed by partially cutting off this curved surface. These four planes are called cut surfaces 34C.

The lower end of the cut surface 34C surrounds the light exit surface 34S. That is, the lower end defines the shape of the light exit surface 34S. Therefore, by providing the cut surface 34C, the shape of the light emitting surface 34S can be made into any planar shape. For example, in the examples shown in FIGS. 4 and 5, the shape of the light exit surface 34S is a rectangle. The shape of the light emitting surface 34S corresponds to the shape of the light receiving section 33a of the solid-state image sensor 33. According to such a configuration, the radiation detector 1 can be downsized.

The cut surface 34C can be defined, for example, by the angle A1 between the axis AZ along the X-ray incident direction RA and a virtual plane AX perpendicular to the axis AZ, and the position of the intersection between the virtual plane including the cut surface 34C and the axis AZ. . The angle A1 is 30 degrees or more and 60 degrees or less. For example, the angle A1 may be 50 degrees. Moreover, according to the cut surface 34C, interference with components arranged around the fiber optic plate 34 can be avoided. Such a configuration also allows the radiation detector 1 to be miniaturized. Moreover, when assembling the radiation detector 1, for example, in the step of connecting the solid-state image sensor 33 and the fiber optic plate 34, a jig is used for positioning or fixing the circuit board 32 to which the package 31 is attached. In this case, by providing the cut surface 34C, it becomes difficult for the fiber optic plate 34 to interfere with the jig. In other words, a sufficient working space can be secured around the area where the epoxy optical adhesive 37A that holds the fiber optic plate 34 and the solid-state image sensor 33 together is arranged. Therefore, it is possible to easily assemble the solid-state image sensor 33 and the fiber optic plate 34. In short, the aspect of the cut surface 34C may be determined not only by the shape of the light exit surface 34S but also by the positional relationship with peripheral components.

Referring again to FIGS. 1 and 2, a scintillator 35 is formed on the light incident surface 34R of the fiber optical plate 34. The scintillator 35 converts X-rays incident from the first end surface 35R into light. The wavelength band of light corresponds to the wavelength band to which the solid-state image sensor 33 has sensitivity. Then, the scintillator 35 emits light from the second end surface 35S. The scintillator 35 is made of columnar crystals or granular crystals of CsI, NaI, or the like. An organic film is provided on the surface of the scintillator 35. This organic film prevents air from coming into contact with the scintillator 35. As a result, in the case of a deliquescent scintillator, deterioration in luminous efficiency due to deliquescence is suppressed. In the case of a scintillator that does not have deliquescent properties, it is not necessary to form an organic film. The organic membrane is made of xylylene resin such as polyparaxylylene or polyparachloroxylylene, which has high X-ray permeability and extremely low permeation of water vapor and gas. A CVD (chemical vapor deposition) method or the like is used to form the organic film. These parylene coatings have extremely low permeation of water vapor and gas. Furthermore, these coating films also have high water repellency and chemical resistance. Moreover, these coating films have excellent electrical insulation properties even if they are thin films, and are transparent to radiation and visible light. A reflective thin film made of gold, silver, aluminum, etc. is provided on the outside or inside of the organic film. Of the light generated by the scintillator 35, the reflective thin film reflects the light that is directed toward the X-ray incident surface, not toward the solid-state imaging device 33 (fiber optical plate 34). As a result, the loss of light is reduced, so the sensitivity of the radiation detector 1 can be increased. Further, the reflective film can also block light that enters from the outside and becomes noise.

A filter 41 is arranged on the first end surface 35R side of the scintillator 35. The filter 41 selectively transmits X-rays received by the scintillator 35 . The filter 41 is a circular or rectangular flat plate that covers the first end surface 35R. The rectangular filter 41 is removably fixed to the fixing member 22 via spacers 42 at each corner. The length of the spacer 42 is set so that the distance between the filter 41 and the scintillator 35 is a predetermined value. The filter 41 may be an aluminum plate member. The thickness of the filter 41 is approximately 1 mm. The filter 41 made of aluminum blocks low-energy X-rays and transmits high-energy X-rays. As a result, high-energy X-rays can be detected with high accuracy. Further, the material and thickness of the filter 41 may be selected as appropriate depending on the energy level of the X-rays to be detected.

Note that the filter 41 is not limited to a plate-shaped member. For example, a case-shaped component having a side portion that covers the side surface of the fiber optic plate 34 may be employed as the filter 41. Since the filter 41 has a side portion, the side surface of the fiber optic plate 34 can be reliably shielded from light.

The drive circuit 4 is electrically connected to the second end side of the flexible substrate 38. The drive circuit 4 includes an arithmetic processing section that performs predetermined arithmetic processing, an amplification section that amplifies the output of the arithmetic processing section, and the like. The drive circuit 4 is housed within a case 21. More specifically, the inner surface of the case 21 is provided with a protrusion 21a. This protrusion 21a is structurally integral with the case 21. The drive circuit 4 is fixed to this protrusion 21a. For example, a corner of the drive circuit 4 is placed on the protrusion 21a. A through hole is provided in a portion of the mounted drive circuit 4 and the protrusion 21a so as to pass through each other. By inserting the fastening parts 21b into these through holes, the drive circuit 4 is fixed to the protrusion 21a. Due to this fixation, the drive circuit 4 does not move significantly with respect to the protrusion 21a. In other words, the drive circuit 4 does not cause any significant movement with respect to the case 21, nor does it cause any significant movement with respect to the housing 2 including the case 21.

The radiation detector 1 can be applied to, for example, an X-ray drilling device 200 (drilling device) shown in FIG. The X-ray drilling device 200 provides a guide hole in the workpiece 101. When performing this drilling process, it is necessary to accurately align the drilling mechanism 102 with the position in the workpiece 101 where the hole is to be provided. The radiation detector 1 is used for positioning the drilling mechanism 102. That is, the X-ray drilling apparatus 200 includes a radiation emitting device 103 (radiation emitting section), a radiation detector 1 (radiation detecting section), a drilling mechanism 102 (drilling section), and a moving mechanism 104. The radiation emitting device 103 is disposed on the first surface 101a side of the workpiece 101, and irradiates radiation toward the first surface 101a. The radiation may be, for example, an X-ray. The radiation detector 1 is placed on the second surface 101b side of the workpiece 101. The second surface 101b is the back side of the first surface 101a. That is, the radiation emitting device 103 and the radiation detector 1 are arranged so as to sandwich the workpiece 101 therebetween.

The radiation detector 1 measures the position of a marker provided on the workpiece 101. The position of the drilling mechanism 102 with respect to the workpiece 101 is controlled using the position information of the marker. The radiation detector 1 moves along the XY plane with respect to a workpiece 101 such as a circuit board in order to measure the marker. The moving speed of the radiation detector 1 is, for example, 50 cm/sec. That is, the radiation detector 1 is movable along two axes. The X-ray drilling device 200 includes a moving mechanism 104 for moving the radiation emitting device 103, the radiation detector 1, and the drilling mechanism 102. The moving mechanism 104 moves the radiation detector 1 relative to the workpiece 101. The drilling mechanism 102 forms a through hole in the workpiece 101. The drilling mechanism 102 may employ a drill device or a laser device. In the example shown in FIG. 6, the drilling mechanism 102 is arranged on the first surface 101a side, but may be arranged on the second surface 101b side.

Incidentally, it is desired that an X-ray drilling apparatus 200 as shown in FIG. 6 has an improved processing speed. In order to improve processing speed, it is necessary to quickly obtain marker position information. In this case, it is necessary to quickly move the radiation detector 1 to the area where the marker is set. Assume that after moving the radiation detector 1 to a target position at high speed, the radiation detector 1 is stopped at the target position. Then, an inertial force corresponding to the mass of each component acts on each component constituting the radiation detector 1. For example, the mass of the fiber optic plate 34 is greater than the mass of the drive circuit 4. Therefore, the inertial force acting on the fiber optic plate 34 is greater than the inertial force acting on the drive circuit 4. This difference in inertial force causes a change in relative position between the fiber optic plate 34 and the drive circuit 4. Such changes in relative position can also be caused by vibrations, shocks, temperature changes, and the like.

Here, as in the radiation detector 300 of the comparative example shown in FIG. is connected to. According to this connection configuration, the circuit board 332 and the drive circuit 4 can be considered to be structurally integrated. Furthermore, the fiber optic plate 34 is held by the housing 2 via a first holding member 39, and the drive circuit 4 is held by the housing 2 via a fixing member 22. In such a structure, if a relative positional change occurs between the fiber optic plate 34 and the drive circuit 4, a load will be applied to the connecting portion between the fiber optic plate 34 and the drive circuit 4, that is, the solid-state image sensor 33. It will happen. In other words, since the respective component parts are connected to each other by a strong fixation that does not allow relative movement, relative positional changes between the parts are difficult to tolerate. As a result, a load (stress) is generated on one of the parts. According to this load, the connection state between the fiber optic plate 34 and the solid-state image sensor 33 changes. For example, the epoxy optical adhesive 37A that holds the solid-state image sensor 33 on the fiber optic plate 34 may peel off. As a result, the reliability of the radiation detector 1 is impaired. This load increases as the degree of relative position change increases. It can be said that the degree of relative positional change depends on, for example, the difference in mass between the parts. Furthermore, even if the radiation detector 1 is moved at high speed in order to respond to the increase in processing speed in the X-ray drilling apparatus 200, the degree of relative positional change increases.

Therefore, the larger the fiber optical plate 34 is made for the purpose of improving detection sensitivity, the greater the degree of relative position change becomes, and the higher the moving speed of the radiation detector 1 is for the purpose of improving processing speed. The degree of relative position change increases. As a result, the load generated between the parts also increases.

One of the causes of the above-mentioned problem is that the plurality of parts are firmly fixed to each other. Therefore, the radiation detector 1 of the embodiment adopts a configuration that actively allows relative positional changes between components.

Specifically, a configuration was adopted in which the circuit board 32 to which the package 31 was attached and the drive circuit 4 were electrically connected by a flexible board 38 and were not mechanically connected. In other words, in this configuration, the solid-state image sensor 33 is not firmly fixed to the housing 2. The housing 2 accommodates a first structure in which the scintillator 35, the fiber optic plate 34, and the solid-state image sensor 33 are integrated, and a second structure including the drive circuit 4. Furthermore, a first structure is held to the housing 2 and a second structure is held to the housing 2 at another position. The first structure and the second structure are only electrically connected and not mechanically connected. In other words, the solid-state image sensor 33 is not directly fixed to the housing 2.

Note that the circuit board 32 only needs to be movable with respect to the drive circuit 4 and/or the housing 2, so its physical configuration may take several forms. For example, the circuit board 32 may be in contact only with the fiber optic plate 34 and not directly with the housing 2. Furthermore, the circuit board 32 may simply be placed on a portion such as the protrusion 21a, for example. In this case, the circuit board 32 cannot move in the direction of the X-ray incident direction RA, but is allowed to move in the direction perpendicular to the X-ray incident direction RA. On the other hand, a gap is required between the side surfaces of the package 31 and the circuit board 32 and the inner surface of the casing 2 to allow movement.

According to such a configuration, even if a force that causes a change in the relative positional relationship between the fiber optic plate 34 and the drive circuit 4 is applied, the flexible substrate 38 does not hinder the relative movement, so that the fiber The optical plate 34, the circuit board 32, and the drive circuit 4 can each move independently. As a result, no load is generated between the circuit board 32 and the drive circuit 4. Therefore, a desired shape and size of the fiber optic plate 34 can be selected from the viewpoint of detection accuracy. Furthermore, it becomes possible to relax the upper limit on the moving speed of the radiation detector 1.

In short, the radiation detector 1 includes a scintillator 35 that generates light corresponding to received radiation, a fiber optical plate 34 that receives the light generated by the scintillator 35 from a light incidence surface 34R and emits it from a light exit surface 34S, and a An imaging unit 5 having a light receiving unit 33a that receives light emitted from the output surface 34S and a solid-state image sensor 33 that generates an electrical signal corresponding to the received light; and a drive circuit 4 that receives the electrical signal from the solid-state image sensor 33. , a housing 2 that houses the imaging unit 5 and the drive circuit 4, a first holding member 39 that maintains the position of the imaging unit 5 with respect to the housing 2, and an epoxy resin that maintains the position of the light output surface 34S with respect to the light receiving unit 33a. An optical adhesive 37A is provided. The fiber optic plate 34 and the imaging section 5 are integrated with an epoxy optical adhesive 37A. The imaging unit 5 is movable with respect to the drive circuit 4.

In the radiation detector 1, the fiber optical plate 34 and the imaging section 5 can be regarded as an integrated structure. These are integrally held in the housing 2 by a first holding member 39. On the other hand, the imaging unit 5 is movable with respect to the drive circuit 4. In this way, even if a relative positional change occurs between the imaging unit 5, which is integrated with the fiber optic plate 34, which has a relatively large mass, and the drive circuit 4, which has a relatively small mass, each can move independently. is possible. In other words, no load is generated between the imaging unit 5 and the drive circuit 4 due to a change in relative position. As a result, it becomes possible to determine the size and mass of the fiber optic plate 34 without being influenced by the characteristics of the drive circuit 4. Therefore, the scintillator 35 can be made larger.

The radiation detector 1 further includes a protrusion 21a that fixes the drive circuit 4 to the housing 2. According to this configuration, the drive circuit 4 can be securely fixed.

The radiation detector 1 further includes a flexible substrate 38 that transmits electrical signals from the imaging section 5 to the drive circuit 4 and has flexibility. According to this configuration, it is possible to realize a configuration in which an electric signal is transmitted from the imaging section 5 to the driving circuit 4 while allowing movement of the driving circuit 4 with respect to the imaging section 5.

The fiber optic plate 34 includes a downstream portion 34b, which is a tapered portion that is provided on the light exit surface 34S side and has a cross-sectional area that gradually becomes smaller along the direction in which light travels. In other words, the area of the light exit surface 34S is smaller than the area of the light entrance surface 34R. According to this configuration, the area of the light incident surface 34R can be increased to increase sensitivity, and the area of the light exit surface 34S can be decreased to reduce the size of the image sensor.

A cut surface 34C is provided on the side surface of the fiber optic plate 34 on the light exit surface 34S side. According to this configuration, the fiber optic plate 34 can be suitably arranged in the housing 2.

The imaging section 5 includes an element mounting surface 31a to which the solid-state image sensor 33 is mounted, and a frame section 31b that stands up from the element mounting surface 31a. According to this configuration, the solid-state image sensor 33 and the fiber optic plate 34 can be connected while protecting the solid-state image sensor 33.

The first holding member 39 is made of epoxy resin or silicone rubber. According to this configuration, the fiber optic plate 34 can be reliably held in the housing 2.

The epoxy optical adhesive 37A is an epoxy resin. According to this configuration, the position of the light emitting surface 34S with respect to the light receiving section 33a can be suitably maintained.

The X-ray drilling device 200 includes a radiation emitting device 103 that is disposed on the first surface 101a side of the workpiece 101 and irradiates radiation toward the first surface 101a of the workpiece 101; A radiation detector 1 is disposed on a second surface 101b side opposite to the first surface 101a of the radiation detector 1 and receives radiation emitted from the radiation detector 1 and transmitted through the workpiece 101; 1 relative to the workpiece 101, and a drilling mechanism 102 that forms a through hole in the workpiece 101. The radiation detector 1 includes a scintillator 35 that generates light corresponding to received radiation, and a fiber that receives the light generated by the scintillator 35 from a light entrance surface 34R and outputs it from a light exit surface 34S that is smaller than the light entrance surface 34R. an optical plate 34; an imaging section 5 having a light receiving section 33a that receives light emitted from the light emitting surface 34S; and a solid-state imaging device 33 that generates an electrical signal corresponding to the received light; A drive circuit 4 that receives signals, a housing 2 that houses the imaging unit 5 and the drive circuit 4, a first holding member 39 that holds the position of the imaging unit 5 with respect to the housing 2, and a light exit surface 34S for the light receiving unit 33a. and an epoxy optical adhesive 37A that holds the position. The imaging unit 5 is movable with respect to the drive circuit 4.

This X-ray drilling apparatus 200 includes the radiation detector 1 described above. Therefore, the detection accuracy of the drilling position can be improved by using the fiber optic plate 34 which can be made larger. Furthermore, although the radiation detector 1 is equipped with a large fiber optic plate 34, it is also possible to increase the movement speed. Therefore, processing speed can be increased.

The present invention has been described above in detail based on the embodiments thereof. However, the present invention is not limited to the above embodiments. The present invention can be modified in various ways without departing from the gist thereof.

In the radiation detector 1 of the embodiment, a package 31 containing a solid-state image sensor 33 was connected to a flexible board 38 via a circuit board 32. For example, the radiation detector may omit the circuit board 32. In this case, the first end of the flexible substrate 38 is directly electrically connected to the package 31.

Furthermore, the application of the radiation detector 1 is not limited to the X-ray drilling apparatus 200. For example, the radiation detector 1 may be applied to a synchrotron radiation beam monitor or an X-ray imaging camera.

DESCRIPTION OF SYMBOLS 1... Radiation detector (radiation detection part), 2... Housing, 3... X-ray detection part, 4... Drive circuit, 5... Imaging part, 21... Case, 21a... Projection part, 21b... Fastening parts, 22... Fixation Member, 22h... Through hole, 22t... Inner peripheral surface, 23... Connection terminal, 31... Package, 31S... Recess, 31a... Element mounting surface, 31b... Frame, 32... Circuit board, 33... Solid-state imaging device, 33a... Light receiving part, 34... Fiber optical plate, 34C... Cut surface, 34R... Light incident surface, 34S... Light exit surface, 34a... Upstream section, 34b... Downstream section (tapered section), 34t... Supported surface, 35... Scintillator, 35R...First end surface, 35S...Second end surface, 36...Closing member, 36h...Opening, 37A...Epoxy optical adhesive (second holding member), 37B...Coating member, 38...Flexible substrate, 39...First Holding member, 41...Filter, 42...Spacer, 200...X-ray drilling device, 101...Workpiece, 101a...First surface, 101b...Second surface, 102...Drilling mechanism (drilling part), 103 ...Radiation emitting device, 104...Movement mechanism, 332...Circuit board, 333...Electrode pin, 200...X-ray drilling device (hole punching device), RA...X-ray incident direction.

Claims (10)

a scintillator that generates light corresponding to the received radiation;
a fiber optical plate that receives the light generated by the scintillator from a light incident surface and emits the light from a light exit surface;
an imaging section having a light receiving section that receives the light emitted from the light emitting surface and a solid-state imaging device that generates an electric signal corresponding to the received light;
a drive circuit that receives the electrical signal from the solid-state image sensor;
a casing that accommodates the imaging unit and the drive circuit;
a first holding member that holds the position of the imaging unit with respect to the housing;
a second holding member that holds the position of the light emitting surface with respect to the light receiving section;
The fiber optic plate and the imaging section are integrated by the second holding member,
The imaging unit is a radiation detector that is movable with respect to the drive circuit. The radiation detector according to claim 1, further comprising a fixing member that fixes the drive circuit to the housing. The radiation detector according to claim 1 or 2, further comprising a flexible substrate that transmits the electrical signal from the imaging section to the drive circuit and has flexibility. The radiation detector according to any one of claims 1 to 3, wherein the fiber optical plate includes a tapered portion provided on the light exit surface side and whose cross-sectional area gradually becomes smaller along the traveling direction of the light. . The radiation detector according to any one of claims 1 to 4, wherein a cut surface is provided on a side surface of the fiber optical plate on the light exit surface side. The imaging unit includes:
an element mounting surface on which the solid-state image sensor is attached;
The radiation detector according to any one of claims 1 to 5, further comprising a frame portion erected from the element mounting surface. The radiation detector according to any one of claims 1 to 6, wherein the first holding member is made of epoxy resin or silicone rubber. The radiation detector according to any one of claims 1 to 7, wherein the second holding member is made of epoxy resin. The radiation detector according to any one of claims 1 to 8, wherein the area of the light exit surface is smaller than the area of the light entrance surface. a radiation emitting unit that is disposed on a first surface side of the workpiece and irradiates radiation toward the first surface of the workpiece;
a radiation detection section that is disposed on a second surface side of the workpiece opposite to the first surface and receives the radiation irradiated from the radiation emitting section and transmitted through the workpiece;
a movement mechanism that moves the radiation detection section relative to the workpiece;
a drilling section for forming a through hole in the workpiece,
The radiation detection section includes:
a scintillator that generates light corresponding to the received radiation;
a fiber optical plate that receives the light generated by the scintillator from a light incident surface and emits the light from a light exit surface;
an imaging section having a light receiving section that receives the light emitted from the light emitting surface and a solid-state imaging device that generates an electric signal corresponding to the received light;
a drive circuit that receives the electrical signal from the solid-state image sensor;
a casing that accommodates the imaging unit and the drive circuit;
a first holding member that holds the position of the imaging unit with respect to the housing;
a second holding member that holds the position of the light emitting surface with respect to the light receiving section;
The fiber optic plate and the imaging section are integrated by the second holding member,
The drilling device, wherein the imaging section is movable with respect to the drive circuit.

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