JP2012021913A - Radiation detector and radiation image photographing apparatus - Google Patents

Abstract

A radiation detector and a radiographic imaging apparatus capable of suppressing warpage due to a temperature change regardless of adhesive strength.
A scintillator layer that converts incident radiation X into light, a scintillator layer provided on the surface, a light detection substrate that converts light emitted from the scintillator layer into electric charge, and a coefficient of thermal expansion. Are formed by joining two different metal plates, provided on the light detection substrate 30 side or the scintillator layer 36 side, one metal plate close to the coefficient of thermal expansion of the provided location is arranged on the inside, and the other And a bimetal 60 that suppresses the warpage of the light detection substrate 30.
[Selection] Figure 4

Description

  The present invention relates to a radiation detector and a radiation image capturing apparatus.

  In recent years, radiation detectors such as an FPD (Flat Panel Detector) capable of directly converting radiation into digital data by arranging a radiation sensitive layer on a TFT (Thin Film Transistor) active matrix substrate have been put into practical use. This radiation detector has an advantage that an image can be confirmed immediately and a moving image can be confirmed as compared with a conventional imaging plate. Radiation detectors convert radiation into indirect conversion methods in which radiation is converted into light by a scintillator and then converted into charges in a semiconductor layer such as a photodiode, or radiation is charged in a semiconductor layer such as amorphous selenium. There are various types of materials that can be used for the semiconductor layer in each method.

  A radiographic imaging apparatus (hereinafter also referred to as an electronic cassette) that incorporates this radiation detector and stores radiation image data output from the radiation detector has been put into practical use.

  Since this electronic cassette has portability, the patient (patient) can be photographed while being placed on a stretcher or bed, and the photographing location can be adjusted by changing the position of the electronic cassette. It is possible to flexibly deal with patients who are not.

  By the way, the radiation detector built in the electronic cassette is a thermal expansion coefficient (coefficient) of the active matrix substrate and the radiation sensitive layer constituting the radiation detector or the substrate for depositing the active matrix substrate and the radiation sensitive layer. If the coefficients of thermal expansion are different from each other, thermal expansion may occur due to a temperature change inside the electronic cassette and warp in the out-of-plane direction.

  Therefore, Patent Document 1 discloses a light conversion layer, a substrate having a coefficient of thermal expansion different from that of the light conversion layer, and a deformation of the light conversion layer and the substrate that are provided in the light conversion layer and are caused by thermal expansion. There is disclosed a solid state detector comprising a deformation suppressing layer for suppressing the above. Specifically, when the thermal expansion coefficient of the substrate is smaller than the thermal expansion coefficient of the light conversion layer, the thermal expansion coefficient of the deformation suppression layer is made smaller than the thermal expansion coefficient of the light conversion layer, and conversely the thermal expansion coefficient of the substrate. Is larger than the thermal expansion coefficient of the light conversion layer, the thermal expansion coefficient of the deformation suppression layer is made larger than the thermal expansion coefficient of the light conversion layer to suppress deformation of the light conversion layer and the substrate due to thermal expansion.

  Patent Document 2 discloses a photoconductive layer, a substrate having a thermal expansion coefficient smaller than that of the photoconductive layer, and a thermal expansion larger than the thermal expansion coefficient of the substrate fixed to the substrate with an adhesive. A radiation detector comprising a deformation suppression layer having a rate is disclosed.

Japanese Patent Laid-Open No. 2003-209232 JP 2008-235657 A

  However, in the configuration of Patent Document 1, it is necessary to fix the deformation suppression layer to the light conversion layer with an adhesive or the like. However, since the thermal expansion coefficients of the deformation suppression layer and the light conversion layer are different, there is a temperature change. However, the thermal expansion amounts of the deformation suppression layer and the light conversion layer are different, and depending on the adhesive strength of the adhesive that bonds and fixes them, the adhesive may be peeled off and the deformation suppression layer may not function.

  Similarly, in the configuration of Patent Document 2, the deformation suppression layer is fixed to the substrate with an adhesive. However, since the coefficient of thermal expansion of the deformation suppression layer and the substrate is different, the deformation suppression layer The thermal expansion amounts of the substrates are different, and depending on the adhesive strength of the adhesive that bonds and fixes them, the adhesive may be peeled off and the deformation suppression layer may not function.

  The present invention has been made in view of the above-described facts, and an object of the present invention is to provide a radiation detector and a radiographic imaging apparatus capable of suppressing warpage due to a temperature change regardless of adhesive strength.

  The radiation detector according to the first aspect of the present invention includes a scintillator layer that converts incident radiation into light, and a photodetection that includes the scintillator layer on a surface and converts light emitted from the scintillator layer into electric charge. A substrate and two metal plates having different thermal expansion coefficients are joined to each other, provided on the light detection substrate side or the scintillator layer side, and one metal plate close to the thermal expansion coefficient at the provided location. A bimetal disposed on the inner side and the other metal plate disposed on the outer side to suppress warpage of the light detection substrate.

According to this configuration, the place where the bimetal is provided, that is, one metal plate close to the coefficient of thermal expansion of the light detection substrate or the scintillator layer is arranged on the inner side (the place where the scintillator is provided). The difference in thermal expansion between the place where the bimetal is provided and one metal plate of the bimetal can be reduced, and the place where the bimetal is provided and the one metal plate are pasted together with an adhesive having low adhesive strength. Moreover, it can suppress that an adhesive peels according to the difference in the amount of thermal expansion when there is a temperature change. In addition, the warp of the light detection substrate caused by a temperature change can be suppressed by a bimetal composed of two metal plates.
Accordingly, since the warpage can be suppressed even when the adhesive strength is low, it is possible to provide a radiation detector capable of suppressing the warpage due to the temperature change regardless of the adhesive strength.

  In the radiation detector according to the second aspect of the present invention, a support for the scintillator layer is provided on the scintillator layer side, and the bimetal is provided on the light detection substrate or the support.

  Thus, even if the scintillator layer support is provided on the scintillator layer side, since the bimetal is provided on the photodetection substrate or the support, warpage of the photodetection substrate can be suppressed.

  In the radiation detector according to the third aspect of the present invention, the support has a higher coefficient of thermal expansion than the photodetection substrate.

  According to this configuration, when the temperature changes, the thermal expansion amount of the support becomes larger than the thermal expansion amount of the light detection substrate, and the possibility that the light detection substrate and the support warp increases. Even in such a case, the bimetal can surely suppress the warpage of the light detection substrate and the support.

  In the radiation detector according to the fourth aspect of the present invention, the scintillator layer includes a plurality of columnar crystals.

  Thus, the scintillator layer can also be configured to include a plurality of columnar crystals.

  In the radiation detector according to a fifth aspect of the present invention, the bimetal is provided on a side of the photodetection substrate or the support that has a high coefficient of thermal expansion.

  According to this configuration, since the bimetal is provided on the light detection substrate or the support that causes the warp, it is possible to reliably suppress the warp of the radiation detector.

  In the radiation detector according to the sixth aspect of the present invention, the bimetal is provided on the support, and the light detection substrate is a radiation irradiation surface.

  According to this configuration, the radiation is applied to the scintillator layer after passing through the light detection substrate. That is, since the scintillator layer is irradiated without going through the bimetal, the bimetal does not interfere with the radiation, and the image quality obtained from the radiation can be prevented from deteriorating.

  In the radiation detector according to the seventh aspect of the present invention, the bimetal is provided in a portion where warpage occurs due to thermal expansion on the light detection substrate side or the scintillator layer side.

  According to this structure, the curvature by the thermal expansion of a photon detection board | substrate can be suppressed reliably.

  In the radiation detector according to the eighth aspect of the present invention, the bimetal is provided in a central portion on the light detection substrate side or the scintillator layer side.

  According to this configuration, it is possible to reliably suppress the warpage of the central portion where the warpage amount due to the temperature change is large.

  In the radiation detector according to the ninth aspect of the present invention, the bimetal is provided in a portion having a low breaking strength on the light detection substrate side or the scintillator layer side.

  According to this configuration, it is possible to reliably suppress warpage of a portion that is easily destroyed and prevent the destruction.

  In the radiation detector according to the tenth aspect of the present invention, the bimetal is bonded to the provided place with an adhesive.

  In this way, even when the bimetal is bonded to the place where the bimetal is provided with an adhesive, the amount of thermal expansion between the place where the bimetal is provided and one of the metal plates of the bimetal is opposed to each other. Since the difference can be reduced, there is no fear of the adhesive peeling due to the difference in thermal expansion.

  A radiation detector according to an eleventh aspect of the present invention includes a housing and the radiation detector according to any one of the above, which is stored in the housing, and the bimetal of the radiation detector includes the bimetal Attached to the housing and spaced apart from the other components of the radiation detector.

According to this configuration, since the bimetal is attached to the housing, when there is a temperature change, it will warp in the other configuration direction of the radiation detector, and the warp of the light detection substrate and thus the radiation detector will be Can be suppressed. That is, even if the bimetal is not bonded to the other components of the radiation detector by an adhesive (even if the adhesive strength is 0), the bimetal can be warped so as to suppress the warpage of the light detection substrate due to a temperature change. Become.
Also, since the bimetal is separated from the other components of the radiation detector, the bimetal warps due to temperature changes and comes into contact with the other components of the radiation detector, and then the bimetallic warping force is applied to the light detection substrate. The warp of the light detection substrate is suppressed. As a result, the warpage of the light detection substrate is accepted before the contact, the frequency of applying the bimetallic warping force to the light detection substrate is reduced, and the occurrence of cracks in the light detection substrate or the scintillator layer is suppressed. be able to.

  A radiographic imaging device according to a twelfth aspect of the present invention includes a radiation detector according to any one of the above, a first temperature sensor that detects a temperature of the photodetection substrate or the scintillator layer, and a temperature of the bimetal. And a warning means for issuing a warning when it is determined that the radiation detector is warped based on the detected temperatures of the first temperature sensor and the second temperature sensor.

  According to this configuration, for example, when the detected temperatures of the first temperature sensor and the second temperature sensor are greatly different, that is, when the temperature of the light detection substrate or scintillator layer and the bimetal is greatly different, the amount of warpage of the bimetal is less than the light amount. Even if there is a bimetal, the photodetection substrate and the scintillator layer, that is, the radiation detector may be warped because the amount of warpage of the detection substrate and the scintillator layer is less than or exceeded. Even in such a case, since the warning means can determine that the radiation detector is warped based on the detected temperatures of the first temperature sensor and the second temperature sensor and issue a warning, the radiation detector is warped. It is possible to prevent malfunctions such as sometimes starting a shooting operation.

  A radiographic imaging device according to a thirteenth aspect of the present invention is the radiation detector according to any one of the above, a first temperature sensor that detects a temperature of the light detection substrate or the scintillator layer, and a temperature of the bimetal. When there is a difference in detection temperature between the second temperature sensor for detecting the temperature and the first temperature sensor and the second temperature sensor, the temperature of the photodetection substrate and the scintillator layer is equal to the temperature of the bimetal. And a temperature adjusting mechanism.

  According to this configuration, even if there is a difference between the temperature of the light detection substrate or scintillator layer and the temperature of the bimetal, the temperature adjustment mechanism makes the temperature of the light detection substrate and scintillator layer the same as that of the bimetal. The warpage of the vessel can be reliably suppressed.

  A radiographic imaging device according to a fourteenth aspect of the present invention includes the radiation detector according to any one of the above, and a bimetal control unit that controls the amount of warpage of the bimetal by causing a current to flow through the bimetal.

  According to this configuration, the amount of warp of the bimetal can be appropriately controlled so that the warp can be suppressed, for example, according to the warp of the light detection substrate.

  ADVANTAGE OF THE INVENTION According to this invention, the radiation detector and radiographic imaging apparatus which can suppress the curvature by a temperature change irrespective of adhesive strength can be provided.

It is the schematic which shows arrangement | positioning of the electronic cassette at the time of radiographic image photography. It is a schematic perspective view which shows the internal structure of an electronic cassette. It is a figure which shows the circuit diagram of an electronic cassette. It is sectional drawing which showed the cross-sectional structure of the electronic cassette concerning 1st Embodiment of this invention. It is sectional drawing which showed the cross-sectional structure of the radiation detector which concerns on 1st Embodiment of this invention. It is a figure which shows the modification of the radiation detector which concerns on 1st Embodiment of this invention. It is sectional drawing which showed the cross-sectional structure of the radiation detector which concerns on 2nd Embodiment of this invention. It is a figure which shows the modification of the radiation detector which concerns on 2nd Embodiment of this invention. It is sectional drawing which showed the cross-sectional structure of the radiation detector which concerns on 3rd Embodiment of this invention. It is a figure which shows the modification of the radiation detector which concerns on 3rd Embodiment of this invention. It is sectional drawing which showed the cross-sectional structure of the electronic cassette as an example of the radiographic imaging apparatus which concerns on 4th Embodiment of this invention, (A) is a figure which shows the state before temperature change, (B) is It is a figure which shows the state after temperature change. It is a figure which shows the principal part structure of the electric system of the radiographic imaging system which concerns on 5th Embodiment of this invention. It is sectional drawing which showed the cross-sectional structure of the electronic cassette concerning 5th Embodiment of this invention. It is a flowchart which shows the flow of a process of the warning program performed by CPU in the cassette control part of an electronic cassette. It is a figure which shows the modification of a bimetal, and is a top view of a radiation detector.

(First embodiment)
Hereinafter, the radiation detector and the radiographic imaging apparatus according to the first embodiment of the present invention will be specifically described with reference to the accompanying drawings. In the drawings, members (components) having the same or corresponding functions are denoted by the same reference numerals and description thereof is omitted as appropriate.

-Overall configuration of radiographic imaging device-
First, the configuration of an electronic cassette as an example of a radiographic imaging apparatus according to the first embodiment of the present invention will be described.

  The electronic cassette according to the first embodiment of the present invention has portability, detects radiation from a radiation source that has passed through the subject, generates image information of a radiographic image represented by the detected radiation, and generates the same The radiographic image capturing apparatus is capable of storing the obtained image information, and is specifically configured as follows. The electronic cassette may be configured not to store the generated image information.

  FIG. 1 is a schematic view showing the arrangement of the electronic cassette 10 at the time of radiographic imaging.

  The electronic cassette 10 is arranged at a distance from the radiation generation unit 12 as a radiation source for generating the radiation X at the time of capturing a radiation image. The space between the radiation generation unit 12 and the electronic cassette 10 at this time is an imaging position for the patient 14 as a subject to be positioned. When an instruction to capture a radiographic image is given, the radiation generation unit 12 gives in advance. Radiation X having a radiation dose according to the imaging conditions is emitted. The radiation X emitted from the radiation generation unit 12 passes through the patient 14 located at the imaging position, and is applied to the electronic cassette 10 after carrying image information.

  FIG. 2 is a schematic perspective view showing the internal structure of the electronic cassette 10.

  The electronic cassette 10 is made of a material that transmits the radiation X, and includes a flat housing 16 having a predetermined thickness. And the radiation detector 20 which detects the radiation X which permeate | transmitted the patient 14 from the irradiation surface 18 side of the housing | casing 16 where radiation X is irradiated inside this housing | casing 16, and the said radiation detector 20 are controlled. A control board 22 is provided in order.

  FIG. 3 is a circuit diagram of the electronic cassette 10.

  The radiation detector 20 includes an upper electrode, a semiconductor layer, and a lower electrode, and includes a sensor unit 24 that receives light and accumulates charges, and a TFT switch 26 for reading out the charges accumulated in the sensor unit 24. The configured pixel 28 includes a TFT (Thin Film Transistor) active matrix substrate 30 (hereinafter referred to as a TFT substrate) provided with a number of two-dimensionally provided pixels.

  Further, on the TFT substrate 30, a plurality of scanning wirings 32 for turning on / off the above-described TFT switch 26 and a plurality of signal wirings 34 for reading out charges accumulated in the sensor unit 24 intersect each other. Is provided.

  In the radiation detector 20 according to the first embodiment of the present invention, the scintillator layer 36 is attached to the surface of the TFT substrate 30.

  The scintillator layer 36 converts the irradiated radiation X such as X-rays and γ-rays into light. The sensor unit 24 receives the light emitted from the scintillator layer 36 and accumulates electric charges.

  Each signal wiring 34 has an electrical signal (image signal) indicating a radiation image in accordance with the amount of charge accumulated in the sensor unit 24 when any TFT switch 26 connected to the signal wiring 34 is turned on. Is flowing.

  Further, a plurality of connection connectors 38 are arranged side by side on one end side in the signal wiring 34 direction of the radiation detector 20, and a plurality of connectors 40 are arranged on one end side in the scanning wiring 32 direction. Yes. Each signal wiring 34 is connected to a connector 38, and each scanning wiring 32 is connected to a connector 40.

One end of a flexible cable 42 is electrically connected to these connectors 38. One end of the flexible cable 44 is electrically connected to the connector 40.
The flexible cable 42 and the flexible cable 44 are coupled to the control board 22.

  The control board 22 is provided with a control unit 46 for controlling the imaging operation by the radiation detector 20 and controlling the signal processing for the electric signal flowing through each signal wiring 34. The control unit 46 includes a signal detection circuit 48 and a control unit 46. And a scan signal control circuit 50.

  The signal detection circuit 48 is provided with a plurality of connectors 52, and the other end of the flexible cable 42 described above is electrically connected to these connectors 52. The signal detection circuit 48 incorporates an amplification circuit for amplifying an input electric signal for each signal wiring 34. With this configuration, the signal detection circuit 48 amplifies and detects the electric signal input from each signal wiring 34 by the amplification circuit, and is stored in each sensor unit 24 as information of each pixel 28 constituting the image. Detect the amount of charge.

  On the other hand, the scan signal control circuit 50 is provided with a plurality of connectors 54, and the other end of the flexible cable 44 described above is electrically connected to these connectors 54. A control signal for turning on / off the TFT switch 26 can be output to each scanning wiring 32.

  When taking a radiographic image in such a configuration, the radiation detector 20 is irradiated with the radiation X transmitted through the patient 14. The irradiated radiation X is converted into light by the scintillator layer 36 and irradiated to the sensor unit 24. The sensor unit 24 receives the light emitted from the scintillator layer 36 and accumulates electric charges.

  At the time of image reading, an ON signal (+10 to 20 V) is sequentially applied from the scan signal control circuit 50 to the gate electrode of the TFT switch 26 of the radiation detector 20 via the scanning wiring 32. Thereby, when the TFT switch 26 of the radiation detector 20 is sequentially turned on, an electrical signal corresponding to the amount of charge accumulated in the sensor unit 24 flows out to the signal wiring 34. The signal detection circuit 48 detects the amount of electric charge accumulated in each sensor unit 24 based on the electric signal that has flowed out to the signal wiring 34 of the radiation detector 20 as information of each pixel 28 constituting the image. Thereby, the image information which shows the image shown with the radiation irradiated to the radiation detector 20 is obtained.

-Configuration of electronic cassette 10-
Next, the configuration of the electronic cassette 10 according to the first embodiment of the present invention will be described more specifically. FIG. 4 is a cross-sectional view showing a cross-sectional configuration of the electronic cassette 10 according to the first exemplary embodiment of the present invention.

  As shown in the figure, the electronic cassette 10 is arranged in the housing 16 in order from the opposite side of the irradiation surface 18 irradiated with the radiation X, the control board 22, the base 56, and the first of the present invention. The radiation detector 20 according to one embodiment is incorporated.

The base 56 is placed on the bottom surface inside the housing 16 via support legs 58. The control board 22 is fixed to the lower surface of the base 56. The radiation detector 20 is connected to the control board 22 via the flexible cable 42 and the flexible cable 44 described above.
In the following embodiments, “up” refers to the direction from the control board 22 side to the radiation detector 20 side, and “down” refers to the direction from the radiation detector 20 side to the control board 22 side. .

  The radiation detector 20 according to the first embodiment of the present invention has a rectangular flat plate shape and detects a radiation image expressed by the radiation X transmitted through the patient 14 as described above. It consists of a scintillator layer 36 and a bimetal 60.

  The TFT substrate 30 is placed on a base 56 via a bimetal 60 which will be described later, and the TFT switch 26 and the sensor unit 24 described above are formed on a substrate (not shown).

The substrate material of the TFT substrate 30 is not particularly limited as long as it has a higher thermal expansion coefficient than the scintillator layer 36 in the first embodiment. As the substrate material, all materials generally used as substrates can be used. For example, in addition to inorganic materials such as YSZ (zirconia stabilized yttrium) and glass, saturated polyester resins, polyethylene terephthalate (PET) systems. Resin, polyethylene naphthalate (PEN) resin, polybutylene terephthalate resin, polystyrene, polycycloolefin, norbornene resin, poly (chlorotrifluoroethylene), crosslinked fumaric acid diester resin, polycarbonate (PC) resin, polyether Sulphone (PES) resin, polysulfone (PSF, PSU) resin, polyarylate (PAR) resin, allyl diglycol carbonate, cyclic polyolefin (COP, COC) resin, cellulosic resin, polyimide (PI) resin, polyamideimide ( AI) resin, maleimide-olefin resin, polyamide (Pa) resin, acrylic resin, fluorine resin, epoxy resin, silicone resin film, polybenzazole resin, episulfide compound, liquid crystal polymer (LCP), cyanate resin And organic materials such as aromatic ether resins. Other composite plastic materials with silicon oxide particles, composite plastic materials with metal nanoparticles / inorganic oxide nanoparticles / inorganic nitride nanoparticles, composites with metal / inorganic nanofibers and / or microfibers Plastic material, carbon fiber, composite plastic material with carbon nanotube, composite plastic material with glass ferret, glass fiber, glass bead, composite plastic material with clay mineral or particles with mica derived crystal structure, thin glass and above alone By alternately laminating a laminated plastic material or inorganic layer (for example, SiO ₂ , Al ₂ O ₃ , SiO _x N _y ) having at least one bonding interface with an organic material and an organic layer made of the above-described material. , Having a barrier performance having at least one bonding interface Aluminum with an oxide film whose surface insulation is improved by applying an oxidation treatment (for example, anodizing treatment) to a composite material, stainless steel, or a metal laminate material obtained by laminating stainless and different metals, an aluminum substrate, or the surface. A substrate can also be used. In the case of the organic material, it is preferable that the organic material is excellent in dimensional stability, solvent resistance, electrical insulation, workability, low air permeability, low hygroscopicity, and the like.

Further, as a substrate material of the TFT substrate 30, bionanofiber can also be used. The bionanofiber is a composite of a cellulose microfibril bundle (bacterial cellulose) produced by bacteria (Acetobacter Xylinum) and a transparent resin. The cellulose microfibril bundle has a width of 50 nm and a size of 1/10 of the visible light wavelength, and has high strength, high elasticity, and low thermal expansion. By impregnating and curing a transparent resin such as an acrylic resin or an epoxy resin in bacterial cellulose, a bio-nanofiber having a light transmittance of about 90% at a wavelength of 500 nm can be obtained while containing 60-70% of the fiber. Bionanofiber has a low coefficient of thermal expansion (3-7ppm) comparable to silicon crystals, and is as strong as steel (460MPa), highly elastic (30GPa), and flexible, compared to glass substrates, etc. A thin TFT substrate 30 can be formed.
A colorless and transparent aramid film can also be used. This aramid film has heat resistance up to 315 ° C., and has an advantageous feature that it has a low coefficient of thermal expansion since it has a thermal expansion coefficient close to that of a glass substrate, and is difficult to break.

The above-described scintillator layer 36 is attached to the upper surface of the TFT substrate 30.
In the first embodiment, the material of the scintillator layer 36 is not particularly limited as long as the coefficient of thermal expansion is lower than that of the TFT substrate 30. As the material of the scintillator layer 36, any material generally used as a scintillator can be used, and examples thereof include GOS (Gd ₂ O ₂ S: Tb).

  On the upper surface side of the scintillator layer 36, the irradiation surface 18 of the housing 16 is disposed through a gap, and the radiation X is irradiated on the surface from the irradiation surface 18. That is, irradiation is performed from the front side where the scintillator layer 36 of the radiation detector 20 is deposited, and the upper end surface 36A of the scintillator layer 36 becomes an irradiation surface of the radiation X when viewed by the radiation detector 20 alone.

  Here, since the thermal expansion coefficients of the TFT substrate 30 and the scintillator layer 36 are different, the TFT substrate 30 and the scintillator layer 36 may be warped due to temperature changes.

  Therefore, in the first embodiment of the present invention, the bimetal 60 that suppresses the warpage of the TFT substrate 30 and the scintillator layer 36 is provided on the TFT substrate 30. Hereinafter, this will be specifically described with reference to FIG.

-Cross-sectional structure of the radiation detector 20-
FIG. 5 is a cross-sectional view showing a cross-sectional configuration of the radiation detector 20 according to the first exemplary embodiment of the present invention.
As shown in the figure, a bimetal 60 is bonded to the TFT substrate 30 on the side where the scintillator layer 36 is not deposited via an adhesive 62.

The size of the bimetal 60 is not particularly limited. For example, the length in the in-plane direction of the bimetal 60 is the same as the length in the in-plane direction of the TFT substrate 30.
The bimetal 60 is configured by joining two metal plates having different thermal expansion coefficients. Of these two metal plates, one metal plate having a high thermal expansion coefficient is disposed inside the out-of-plane direction Z of the radiation detector 20, that is, disposed on the TFT substrate 30 side, and bonded to the TFT substrate 30. ing. The other metal plate is disposed outside the out-of-plane direction Z of the radiation detector 20. Hereinafter, of the two metal plates of the bimetal 60, one metal plate to be bonded to the TFT substrate 30 may be referred to as a high thermal expansion plate 60A, and the other metal plate may be referred to as a low thermal expansion plate 60B.

  Thus, of the two metal plates 60A and 60B, the high thermal expansion plate 60A is bonded to the TFT substrate 30 having a higher thermal expansion coefficient than that of the scintillator layer 36, that is, those having a higher thermal expansion coefficient are bonded together. Thus, the metal plate 60A close to the coefficient of thermal expansion of the TFT substrate 30 is arranged on the TFT substrate 30 side.

-Action-
As described above, according to the radiation detector 20 of the first embodiment of the present invention, the high thermal expansion plate 60A close to the thermal expansion coefficient of the scintillator layer 36 among the two metal plates 60A and 60B of the bimetal 60 is the TFT substrate 30. Therefore, the difference in thermal expansion between the TFT substrate 30 and the high thermal expansion plate 60A arranged on the TFT substrate 30 side can be reduced, and the TFT substrate 30 and the high thermal expansion plate 60A are temporarily bonded with low adhesive strength. Even if the adhesive 62 is bonded, it is possible to prevent the adhesive 62 from being peeled off due to a difference in thermal expansion when there is a temperature change.

Here, since the coefficient of thermal expansion of the TFT substrate 30 is higher than the coefficient of thermal expansion of the scintillator layer 36, the scintillator layer is arranged in one of the two out-of-plane directions Z of the radiation detector 20 when there is a temperature change. 36 and the TFT substrate 30 may be warped. However, according to the radiation detector 20 of the first embodiment of the present invention, of the two metal plates 60A and 60B of the bimetal 60, the high thermal expansion plate 60A is arranged inside the out-of-plane direction Z of the radiation detector 20. Since the low thermal expansion plate 60B is disposed outside the out-of-plane direction Z of the radiation detector 20, a warping force is generated in a direction opposite to the warping direction of the scintillator layer 36 and the TFT substrate 30. The warping force in the reverse direction acts on the scintillator layer 36 and the TFT substrate 30 and can suppress warping of the scintillator layer 36 and the TFT substrate 30.
As described above, since the warpage of the scintillator layer 36 and the TFT substrate 30 can be suppressed even when the adhesive strength of the adhesive 62 is low, it is possible to provide the radiation detector 20 capable of suppressing the warpage due to the temperature change regardless of the adhesive strength. Can do.

  Further, in the radiation detector 20, since the upper end surface 36 </ b> A of the scintillator layer 36 is an irradiation surface of the radiation X, even when the radiation X is irradiated to the radiation detector 20, the radiation X is passed before passing through the bimetal 60. It will hit layer 36. Therefore, the bimetal 60 does not interfere with the irradiation of the radiation X, and the image quality obtained from the radiation X can be prevented from deteriorating.

-Modification-
Next, a modification of the radiation detector 20 according to the first embodiment of the present invention will be described.

In the radiation detector 20 of the first embodiment, the case where the bimetal 60 is provided on the TFT substrate 30 side of the scintillator layer 36 and the TFT substrate 30 in order to suppress warpage of the scintillator layer 36 and the TFT substrate 30 has been described. However, as shown in FIG. 6, in the radiation detector 20 </ b> A of the modification, a bimetal 70 may be provided on the scintillator layer 36 side. The bimetal 70 has the same configuration as the bimetal 60, and is configured by joining two metal plates, a high thermal expansion plate 70A and a low thermal expansion plate 70B.
However, in this case, since the scintillator layer 36 has a lower coefficient of thermal expansion than the TFT substrate 30, the low thermal expansion plate 70 B of the two metal plates 70 A and 70 B of the bimetal 70 is used as the scintillator layer 36. The metal plates 70B close to the thermal expansion coefficient of the scintillator layer 36 are arranged on the scintillator layer 36 side by bonding them together, that is, by bonding together those having a low thermal expansion coefficient.

  According to such a modification, as in the first embodiment, the low thermal expansion plate 70B close to the thermal expansion coefficient of the scintillator layer 36 is disposed on the scintillator layer 36 side, so that the scintillator layer 36 and the scintillator layer 36 are arranged. The difference in thermal expansion amount with the low thermal expansion plate 70B arranged on the side can be reduced, and even if the scintillator layer 36 and the low thermal expansion plate 70B are bonded with the adhesive 62 having low adhesive strength, there is a change in temperature. It is possible to prevent the adhesive 62 from being peeled off due to the difference in thermal expansion amount. Further, the warpage of the scintillator layer 36 and the TFT substrate 30 caused by the temperature change can be suppressed by the bimetal 70 constituted by the two metal plates 70A and 70B.

(Second Embodiment)
Next, a radiation detector according to the second embodiment of the present invention will be described.

−Configuration of radiation detector−
FIG. 7 is a cross-sectional view showing a cross-sectional configuration of the radiation detector 100 according to the second exemplary embodiment of the present invention.
As shown in the figure, the configuration of the radiation detector 100 according to the second embodiment of the present invention is the same as the configuration shown in FIG. 5 described in the first embodiment, but the relationship between the thermal expansion coefficients of the respective configurations. Is different.

  Specifically, in the first embodiment, the TFT substrate 30 has a higher coefficient of thermal expansion than the scintillator layer 36, whereas in the second embodiment, the TFT substrate 102 is more than the scintillator layer 104. It has a low coefficient of thermal expansion. In the first embodiment, of the two metal plates 60A and 60B of the bimetal 60, the high thermal expansion plate 60A is bonded to the TFT substrate 30, whereas in the second embodiment, two of the bimetal 106 are used. Of these metal plates 106A and 106B, the low thermal expansion plate 106B is bonded to the TFT substrate 102.

  Thus, of the two metal plates 106A and 106B of the bimetal 106, the low thermal expansion plate 106B is bonded to the TFT substrate 102 having a thermal expansion coefficient lower than that of the scintillator layer 104, that is, those having a low thermal expansion coefficient. Is attached so that the metal plate 106B having a thermal expansion coefficient close to that of the TFT substrate 30 is arranged on the TFT substrate 102 side.

-Action-
As described above, according to the radiation detector 100 according to the second embodiment of the present invention, the bimetal 106 is provided on the TFT substrate 102, and the thermal expansion coefficient of the TFT substrate 102 among the two metal plates 106 </ b> A and 106 </ b> B of the bimetal 106. Since the metal plate 106 </ b> B close to the TFT substrate 102 is disposed on the TFT substrate 102 side, warpage due to temperature change can be suppressed regardless of the adhesive strength of the adhesive 62 as in the first embodiment.

-Modification-
Next, a modification of the radiation detector 100 according to the second embodiment of the present invention will be described.

In the radiation detector 100 of the second embodiment, the case where the bimetal 106 is provided on the TFT substrate 102 side of the scintillator layer 104 and the TFT substrate 102 in order to suppress the warpage of the scintillator layer 104 and the TFT substrate 102 has been described. However, as shown in FIG. 8, in the radiation detector 100 </ b> A of the modification, a bimetal 110 may be provided on the scintillator layer 104 side. The bimetal 110 has the same configuration as the bimetal 106, and is formed by joining two metal plates, a high thermal expansion plate 110A and a low thermal expansion plate 110B.
However, in this case, since the scintillator layer 104 has a higher coefficient of thermal expansion than the TFT substrate 30, the high thermal expansion plate 110A of the two metal plates 110A and 110B of the bimetal 110 is used as the scintillator layer 104. The metal plates 110A close to the thermal expansion coefficient of the scintillator layer 104 are arranged on the scintillator layer 104 side by bonding them together, that is, by bonding together those having a high thermal expansion coefficient.

(Third embodiment)
Next, a radiation detector according to a third embodiment of the present invention will be described.

−Configuration of radiation detector−
FIG. 9 is a cross-sectional view showing a cross-sectional configuration of a radiation detector 200 according to the third exemplary embodiment of the present invention.
As shown in the figure, the configuration of the radiation detector 200 according to the third embodiment of the present invention is the same as the configuration shown in FIG. 5 described in the first embodiment, and an additional deposition substrate 202 is added. Has been.

  Specifically, in the radiation detector 20 of the first embodiment, the TFT substrate 30 has a higher coefficient of thermal expansion than the scintillator layer 36, whereas in the radiation detector 200 of the third embodiment, The scintillator layer 204 has a columnar structure made of CsI: Tl, CsI: Na (sodium activated cesium iodide), ZnS: Cu, CsBr, or the like, and a gap (not shown) is formed between the columnar crystals. . Since there is this gap, it is assumed that the amount of thermal expansion of the scintillator layer 204 due to temperature change is negligible, and the relationship between the thermal expansion coefficients of the scintillator layer 204 and the TFT substrate 206 is not considered (the same or different). May be) Instead, the coefficient of thermal expansion of the TFT substrate 206 is different from that of the vapor deposition substrate 202, and the vapor deposition substrate 202 has a higher coefficient of thermal expansion than the TFT substrate 206.

The deposition substrate 202 is a substrate used when the scintillator layer 204 is formed by vapor deposition by a vapor deposition method.
The material of the evaporation donor substrate 202 is not particularly limited as long as it has a higher coefficient of thermal expansion than the TFT substrate 206, and the same material as the substrate material of the TFT substrate 206 described above can be used. Preferably, carbon is used in terms of high rigidity, high X-ray transmission, homogeneity, no material unevenness, heat resistance, thermal expansion coefficient close to glass, chemical resistance, and conductivity. be able to. Aluminum can also be used because it has higher thermal conductivity than carbon and is cheaper. Moreover, a bionanofiber and an aramid film can also be used.
The thickness of the evaporation donor substrate 202 is preferably thicker from the viewpoints of improving handling properties, preventing warpage due to the weight of the scintillator layer 204, preventing deformation due to radiant heat, and the like in an evaporation process using a vapor deposition method.

  In the first embodiment, the bimetal 60 is bonded to the TFT substrate 30, whereas in the third embodiment, the bimetal 208 is bonded to the deposition substrate 202. Specifically, in the first embodiment, of the two metal plates 60A and 60B of the bimetal 60, the high thermal expansion plate 60A is bonded to the TFT substrate 30, whereas in the third embodiment, the bimetal 208 is used. Of these two metal plates 208A and 208B, the high thermal expansion plate 208A is bonded to the vapor deposition substrate 202 with an adhesive 62.

  Thus, the high thermal expansion plate 208A of the two metal plates 208A and 208B of the bimetal 208 is bonded to the deposition substrate 202 having a higher thermal expansion coefficient than the TFT substrate 206, that is, the one having a high thermal expansion coefficient. By bonding them together, a metal plate 208A having a thermal expansion coefficient close to that of the vapor deposition substrate 202 is arranged on the vapor deposition substrate 202 side.

In such a case, the configuration in which the radiation X is irradiated on the front surface, that is, when one surface (the upper surface in FIG. 9) of the bimetal 208 is the irradiation surface, it interferes with the radiation X irradiation. Irradiation, that is, one surface (the lower surface in FIG. 9) of the TFT substrate 206 is an irradiation surface.
According to this configuration, the radiation X is applied to the scintillator layer 204 after passing through the TFT substrate 206. That is, since the scintillator layer 204 is irradiated without passing through the bimetal 208, the bimetal 208 does not interfere with the radiation X, and it is possible to prevent the image quality obtained from the radiation X from deteriorating.

-Action-
As described above, according to the radiation detector 200 according to the third embodiment of the present invention, the bimetal 208 is provided on the vapor deposition substrate 202 and the heat of the vapor deposition substrate 202 out of the two metal plates 208A and 208B of the bimetal 208. Since the metal plate 208A having a coefficient of expansion close to that of the vapor deposition substrate 202 is disposed, the vapor deposition substrate 202 and the scintillator layer due to the temperature change, regardless of the adhesive strength of the adhesive 62, as in the first embodiment. 204 and the warpage of the TFT substrate 206 can be suppressed.

  In addition, since the bimetal 208 is provided on the evaporation substrate 202 and the TFT substrate 206 on the side having a high coefficient of thermal expansion, that is, on the evaporation deposition substrate 202 that causes warping, the radiation detector 200 is reliably warped. Can be suppressed.

  Further, since one surface (the lower surface in FIG. 9) of the TFT substrate 206 is an irradiation surface, the radiation X passes through the TFT substrate 206 and is irradiated to the scintillator layer 204. That is, since the scintillator layer 204 is irradiated without passing through the bimetal 208, the bimetal 208 does not interfere with the radiation X, and it is possible to prevent the image quality obtained from the radiation X from deteriorating.

-Modification-
Next, a modification of the radiation detector 200 according to the third embodiment of the present invention will be described.

  In the radiation detector 200 of the third embodiment, in order to suppress warping of the deposition substrate 202, the scintillator layer 204, and the TFT substrate 206, the deposition substrate 202 of the deposition substrate 202 and the TFT substrate 206 are bimetallic on the deposition substrate 202 side. Although the case where 208 is provided has been described, as shown in FIG. 10, in the radiation detector 200A of the modification, a bimetal 210 may be provided on the TFT substrate 206 side. The bimetal 210 has the same configuration as the bimetal 208, and is formed by joining two metal plates, a high thermal expansion plate 210A and a low thermal expansion plate 210B.

However, in this case, since the TFT substrate 206 has a lower coefficient of thermal expansion than the vapor deposition substrate 202, the low thermal expansion plate 210B of the two metal plates 210A and 210B of the bimetal 210 is used as the TFT substrate 206. The metal plates 210B close to the thermal expansion coefficient of the TFT substrate 206 are arranged on the TFT substrate 206 side by bonding together those having low thermal expansion coefficients.
In such a case, if the radiation X is irradiated on the back surface, that is, if one surface of the bimetal 210 (the lower surface in FIG. 10) is an irradiation surface, the radiation X is obstructed, so the surface of the radiation X is irradiated. The surface of the deposition substrate 202 (upper surface in FIG. 10) is the irradiation surface.

(Fourth embodiment)
Next, a radiographic imaging device according to the fourth exemplary embodiment of the present invention will be described.

-Configuration of radiographic imaging device-
FIG. 11 is a cross-sectional view showing a cross-sectional configuration of an electronic cassette 300 as an example of a radiographic image capturing apparatus according to the fourth embodiment of the present invention, and (A) is a view showing a state before a temperature change. (B) is a figure which shows the state after a temperature change.

  The electronic cassette 300 according to the fourth embodiment of the present invention has the same configuration as the electronic cassette 10 shown in FIG. 4 described in the first embodiment, but the configuration and arrangement of bimetals are different.

  Specifically, the bimetal 60 that suppresses the warp of the radiation detector 20 of the first embodiment is bonded to the TFT substrate 30, whereas the bimetal that suppresses the warp of the radiation detector 302 of the fourth embodiment. As shown in FIG. 11A, 304 is not attached to the TFT substrate 30 or the scintillator layer 36, and is attached to the casing 16 of the electronic cassette 300 so that it can be warped due to a temperature change. The TFT 302 is separated from the TFT substrate 30 and the scintillator layer 36 of the vessel 302.

  Further, since the scintillator layer 36 has a lower coefficient of thermal expansion than the TFT substrate 30, the bimetal 304 is warped vertically and symmetrically with the warp of the scintillator layer 36 and the TFT substrate 30. Of the metal plates 304A and 304B, the low thermal expansion plate 304B is disposed on the scintillator layer 36 side.

-Action-
According to the electronic cassette 300 according to the fourth exemplary embodiment of the present invention, since the bimetal 304 is attached to the housing 16, when the temperature changes as shown in FIG. 11B, the scintillator layer 36 and The warpage of the scintillator layer 36 and the TFT substrate 30 can be suppressed by warping in the direction of the TFT substrate 30. That is, even if the bimetal 304 is not bonded to the scintillator layer 36 or the TFT substrate 30 by the adhesive 62 (even if the adhesive strength is 0), the bimetal 304 suppresses the warpage of the scintillator layer 36 and the TFT substrate 30 due to the temperature change. It becomes possible to warp.

  In addition, since the bimetal 304 is separated from the scintillator layer 36 and the TFT substrate 30, the bimetal 304 is warped against the scintillator layer 36 due to a temperature change, and then the warping force of the bimetal 304 is applied to the scintillator layer 36. The warpage of the layer 36 and the TFT substrate 30 is suppressed. As a result, the warpage of the scintillator layer 36 and the TFT substrate 30 is accepted before the contact, the frequency of applying the bimetallic warp force to the scintillator layer 36 is reduced, and the scintillator layer 36 is prevented from cracking. be able to.

(Fifth embodiment)
Next, a radiographic image capturing apparatus and a radiographic image capturing system according to a fifth embodiment of the present invention will be described with reference to the drawings.

-Configuration of radiographic imaging system-
FIG. 12 is a diagram showing the main configuration of the electrical system of the radiation image capturing system 400 according to the fifth embodiment of the present invention.
As shown in the figure, the radiographic image capturing system 400 according to the fifth embodiment of the present invention includes an electronic cassette 410, a console 430, and a radiation generator 460.

The electronic cassette 410 contains, for example, the radiation detector 20 of the first embodiment, and includes a signal detection circuit 48 that is electrically connected to each signal wiring 34 of the TFT substrate 30 of the radiation detector 20. .
The signal detection circuit 48 includes an amplifier and a sample hold circuit provided for each signal wiring 34, and the charge signal transmitted through each signal wiring 34 is amplified by the amplifier and then held in the sample hold circuit. The Further, a multiplexer and an A / D (analog / digital) converter are sequentially connected to the output side of the sample and hold circuit, and the charge signals held in the individual sample and hold circuits are sequentially (serially) input to the multiplexer. The digital image data is converted by an A / D converter.

  An image memory 412 is connected to the signal detection circuit 48, and image data output from the A / D converter of the signal detection circuit 48 is sequentially stored in the image memory 412. The image memory 412 has a storage capacity capable of storing image data for a plurality of frames, and image data obtained by imaging is sequentially stored in the image memory 412 each time a radiographic image is captured.

  The image memory 412 is connected to a cassette control unit 414 that controls the operation of the entire electronic cassette 410. The cassette control unit 414 includes a microcomputer, and includes a CPU (Central Processing Unit) 414A, a memory 414B including a ROM (Read Only Memory) and a RAM (Random Access Memory), an HDD (Hard Disk Drive), and a flash memory. A non-volatile storage unit 414C made up of and the like is provided.

  Also, a buzzer 416 and a temperature sensor 418 are connected to the cassette control unit 414. The operation of the buzzer 416 is controlled by a CPU 414A provided in the cassette control unit 414, while the CPU 414A is detected by the temperature sensor 418. Temperature can be grasped.

  In addition, the cassette control unit 414 is connected to the connection terminal 410A and is a communication interface (I / F) unit that transmits and receives various information to and from the console 430 while being connected to the console 430 via the communication cable 420. 422 is connected.

  The electronic cassette 410 is provided with a power supply unit 424. The power supply unit 424 incorporates a battery (secondary battery) (not shown) so as not to impair the portability of the electronic cassette 410, and supplies power from a charged battery to a predetermined part. In FIG. 12, illustration of wirings that connect the power supply unit 424 and each unit of the power supply destination is omitted.

  In the radiographic image capturing system 400 according to the fifth embodiment, the electronic cassette 410 and the console 430 are connected by the communication cable 420 to transmit and receive various types of information. The communication cable 420 includes a power supply line. Power for driving each part of the electronic cassette 410 is supplied from the console 430 via the communication cable 420.

  The battery (not shown) supplies driving power to the minimum necessary part of the electronic cassette 410 when the electronic cassette 410 is not connected to the console 430 by the communication cable 420. In this case, the electronic cassette 410 according to the embodiment supplies driving power to the cassette control unit 414 and supplies driving power to the buzzer 416 and the temperature sensor 418 as necessary.

  On the other hand, the console 430 is configured as a server computer, and includes a display 432 that displays an operation menu, a captured radiographic image, and the like, and a plurality of keys, and inputs various information and operation instructions. An operation panel 434.

  The console 430 according to the present embodiment includes a CPU 436 that controls the operation of the entire apparatus, a ROM 438 that stores various programs including a control program in advance, a RAM 440 that temporarily stores various data, and various data. An HDD 442 that stores and holds, a display driver 444 that controls display of various types of information on the display 432, and an operation input detection unit 446 that detects an operation state of the operation panel 434 are provided.

  The console 430 is connected to the connection terminal 430A, and is connected to the radiation generator 460 via the communication cable 448. The console 430 transmits and receives various information to and from the radiation generator 460. The communication I / F unit 452 is connected to the connection terminal 430B and transmits / receives various information to / from the electronic cassette 410 while being connected to the electronic cassette 410 via the communication cable 420.

  The CPU 436, the ROM 438, the RAM 440, the HDD 442, the display driver 444, the operation input detection unit 446, the communication I / F unit 450, and the communication I / F unit 452 are connected to each other via the system bus BUS. Therefore, the CPU 436 can access the ROM 438, the RAM 440, and the HDD 442, and controls the display of various information on the display 432 via the display driver 444, the communication I / F unit 450 and the communication I / F unit 452. Control of transmission and reception of various types of information with the radiation generator 460 and the electronic cassette 410 can be performed. Further, the CPU 436 can grasp the operation state of the user with respect to the operation panel 434 via the operation input detection unit 446.

  On the other hand, the radiation generator 460 is connected to the radiation source 462 and the connection terminal 460A, and transmits and receives various information such as exposure conditions to and from the console 430 while being connected to the console 430 via the communication cable 448. A communication I / F unit 464 to perform and a radiation source control unit 466 that controls the radiation source 462 based on the received exposure conditions are provided.

  The radiation source control unit 466 is also configured to include a microcomputer, and stores the received exposure conditions and the like. The exposure conditions received from the console 430 include information such as tube voltage, tube current, and exposure period. The radiation source control unit 466 irradiates the radiation X from the radiation source 462 based on the received exposure conditions.

-Electronic cassette configuration-
Next, the internal configuration of the electronic cassette 410 shown in FIG. 12 will be specifically described with reference to FIG. FIG. 13 is a cross-sectional view showing a cross-sectional configuration of an electronic cassette 410 according to the fifth embodiment.

  In the electronic cassette 410 according to the fifth embodiment, the above-described buzzer 416 and a temperature sensor 418 are further added to the configuration of the electronic cassette 10 of the first embodiment.

  The buzzer 416 is a kind of warning means, and emits a warning by sound when the radiation detector 20 warps due to a temperature change. The arrangement of the buzzer 416 is not particularly limited, but is attached to the lower surface of the base 56 as shown in FIG.

  The temperature sensor 418 includes two temperature sensors, a first temperature sensor 418A that detects the temperature of the scintillator layer 36 (and the TFT substrate 30) and a second temperature sensor 418B that detects the temperature of the bimetal 60. .

  The first temperature sensor 418A is attached to the upper end surface 36A of the scintillator layer 36, for example. Further, the second temperature sensor 418B is attached to, for example, an in-plane direction side surface of the bimetal 60.

-Action-
Next, the operation of the electronic cassette 410 according to the fifth exemplary embodiment of the present invention will be described.

  FIG. 14 is a flowchart showing a processing flow of a warning program executed by the CPU 414A in the cassette control unit 414 of the electronic cassette 410 every predetermined period (in this embodiment, 10 seconds). Is stored in advance in a predetermined area of the ROM of the memory 414B. In the following, the step identification codes in the figure are in parentheses.

(S1000) The detected temperature T1 is acquired from the first temperature sensor 418A.
(S1002) The detected temperature T2 is acquired from the second temperature sensor 418B.
(S1004) It is determined whether or not the difference between the acquired detection temperature T1 and the detection temperature T2 is large, for example, a temperature difference C in which the radiation detector 20 warps. If the determination is affirmative, the process proceeds to step S1006, and if the determination is negative, the process ends.
(S1006) The buzzer 416 is controlled to emit a warning sound for 10 seconds, for example.

  Here, for example, when the detected temperatures of the first temperature sensor 418A and the second temperature sensor 418B are greatly different, that is, when the temperatures of the scintillator layer 36 and the TFT substrate 30 and the bimetal 60 are greatly different, the amount of warpage of the bimetal 60 However, even if the bimetal 60 is present, the radiation detector 20 may be warped because the amount of warpage of the scintillator layer 36 and the TFT substrate 30 is less than or exceeded. However, according to the configuration of the fifth embodiment of the present invention, even in such a case, the cassette control unit 414 operates the radiation detector 20 on the basis of the detected temperatures of the first temperature sensor 418A and the second temperature sensor 418B. Therefore, it is possible to control the buzzer 416 and emit a warning sound, so that it is possible to prevent malfunction such as starting an imaging operation when the radiation detector 20 is warped.

(Modification)
In addition, although this invention was demonstrated in detail about specific 1st-5th embodiment, this invention is not limited to this embodiment, Other various embodiment is possible within the scope of the present invention. It will be apparent to those skilled in the art. For example, the above-described plurality of embodiments can be implemented in combination as appropriate. Moreover, you may combine the following modifications suitably.

  For example, in the first embodiment, the housing 16 includes a radiation detector 20 that detects the radiation X that has passed through the patient 14 from the irradiation surface 18 side of the housing 16 that is irradiated with the radiation X, and a control board. Although the case where 22 is provided in order has been described, in order from the irradiation surface 18 side where the radiation X is irradiated, the grid and the radiation detector 20 that remove scattered radiation of the radiation X caused by passing through the patient 14. , And a lead plate that absorbs backscattered radiation X may be accommodated.

  Moreover, although the case where the shape of the housing | casing 16 was a rectangular flat plate shape was demonstrated in 1st Embodiment, it is not specifically limited, For example, a front view may be made into a square or a circle.

  Moreover, although 1st Embodiment demonstrated the case where the control board 22 was formed by one, this invention is not limited to this embodiment, Even if the control board 22 is divided into several for every function. Good. Furthermore, although the case where the control board 22 is arranged side by side in the vertical direction (thickness direction of the housing 16) with the radiation detector 20 has been described, it may be arranged side by side with the radiation detector 20 in the horizontal direction. .

  Further, the case where the length in the in-plane direction of the bimetal 60 is the same as the length in the in-plane direction of the TFT substrate 30 has been described, but the length may not be the same and the size is not particularly limited. Therefore, for example, the bimetal 60 may be provided on a part of the TFT substrate 30 or the scintillator layer 36 where warpage occurs due to thermal expansion. Specifically, as shown in FIG. 15, the TFT substrate 30 or the scintillator layer is provided in a part including at least the central portion of the TFT substrate 30 or the scintillator layer 36 that has a large amount of warping due to a temperature change. 36 may be provided in a portion having a low breaking strength (for example, a TCP (Tape-Carrier Package) portion including wiring or the like).

  Further, instead of the buzzer 416 of the fifth embodiment, when there is a difference in the detected temperature between the first temperature sensor 418A and the second temperature sensor 418B, the temperature of the scintillator layer 36 and the TFT substrate 30 and the bimetal 60 A temperature adjusting mechanism such as a heater having the same temperature may be provided. According to such a configuration, even if a difference occurs between the temperature of the scintillator layer 36 and the TFT substrate 30 and the temperature of the bimetal 60, the temperature of the scintillator layer 36 and the TFT substrate 30 is equal to the temperature of the bimetal 60 by the temperature adjustment mechanism. Therefore, the curvature of the radiation detector 20 can be reliably suppressed.

  Further, instead of the buzzer 416 of the fifth embodiment, a bimetal control unit that controls the amount of warpage of the bimetal 60 by passing a current through the bimetal 60 may be provided. According to such a configuration, for example, according to the warp of the scintillator layer 36 and the TFT substrate 30, the warp amount of the bimetal 60 can be appropriately controlled so that the warp can be suppressed.

  Further, instead of the buzzer 416 of the fifth embodiment, a warning may be issued by smell, light, or vibration. Further, a warning may be displayed on the screen of the display 432 of the console 430.

10 Electronic cassette (radiation imaging equipment)
16 Housing 20 Radiation detector 20A Radiation detector 30 TFT substrate (light detection substrate)
36 scintillator layer 60 bimetal 62 adhesive 70 bimetal 100 radiation detector 100A radiation detector 102 TFT substrate (light detection substrate)
104 Scintillator layer 106 Bimetal 110 Bimetal 200 Radiation detector 200A Radiation detector 202 Deposition substrate (support)
204 Scintillator layer 206 TFT substrate (photodetection substrate)
208 Bimetal 210 Bimetal 300 Electronic cassette (Radiation imaging equipment)
302 Radiation detector 304 Bimetal 410 Electronic cassette (radiation imaging device)
414 cassette control unit (warning means, temperature adjustment mechanism, bimetal control means)
416 Buzzer (Warning means)
418 Temperature sensor (first temperature sensor, second temperature sensor)
418A First temperature sensor 418B Second temperature sensor T1 Detection temperature T2 Detection temperature X Radiation

Claims (14)

A scintillator layer that converts incident radiation into light;
The scintillator layer is provided on a surface, and a light detection substrate that converts light emitted from the scintillator layer into an electric charge;
Two metal plates with different coefficients of thermal expansion are joined to each other, provided on the light detection substrate side or the scintillator layer side, and one metal plate close to the coefficient of thermal expansion at the provided location is placed inside The other metal plate is arranged on the outside, the bimetal for suppressing the warp of the light detection substrate,
A radiation detector comprising: On the scintillator layer side, a support for the scintillator layer is provided,
The bimetal is provided on the light detection substrate or the support.
The radiation detector according to claim 1. The support has a higher coefficient of thermal expansion than the photodetection substrate.
The radiation detector according to claim 2. The scintillator layer is configured to include a plurality of columnar crystals.
The radiation detector of Claim 2 or Claim 3. The bimetal is provided on the side of the photodetection substrate or the support that has a high coefficient of thermal expansion.
The radiation detector of any one of Claims 2-4. The bimetal is provided on the support, and the light detection substrate is a radiation irradiation surface.
The radiation detector of any one of Claims 2-5. The bimetal is provided on the light detection substrate side or the scintillator layer side where warpage occurs due to thermal expansion.
The radiation detector of any one of Claims 1-6. The bimetal is provided in a central portion on the light detection substrate side or the scintillator layer side,
The radiation detector according to claim 7. The bimetal is provided in a portion having a low breaking strength on the light detection substrate side or the scintillator layer side,
The radiation detector according to claim 7 or 8. The bimetal is bonded to the provided place with an adhesive,
The radiation detector of any one of Claims 1-9. A housing,
The radiation detector according to any one of claims 1 to 9, wherein the radiation detector is stored in the housing.
The bimetal of the radiation detector is attached to the housing and spaced apart from other configurations of the radiation detector;
Radiation imaging device. The radiation detector according to any one of claims 1 to 10,
A first temperature sensor for detecting a temperature of the light detection substrate or the scintillator layer;
A second temperature sensor for detecting the temperature of the bimetal;
Warning means for issuing a warning when it is determined that the radiation detector is warped based on the detected temperatures of the first temperature sensor and the second temperature sensor;
A radiographic imaging apparatus comprising: The radiation detector according to any one of claims 1 to 10,
A first temperature sensor for detecting a temperature of the light detection substrate or the scintillator layer;
A second temperature sensor for detecting the temperature of the bimetal;
When there is a difference in detection temperature between the first temperature sensor and the second temperature sensor, a temperature adjustment mechanism that makes the temperature of the photodetection substrate and the scintillator layer the same as the temperature of the bimetal;
A radiographic imaging apparatus comprising: The radiation detector according to any one of claims 1 to 10,
Bimetal control means for controlling the amount of warpage of the bimetal by passing a current through the bimetal;
A radiographic imaging apparatus comprising:

Images