JP2012018017A - Radiographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation imaging apparatus capable of photographing various radiation images.SOLUTION: A temperature adjustment part 82 is controlled so that the temperature of a radiation detector 20 is within a temperature range where warpage of the radiation detector 20 caused by temperature change including the temperature when a TFT substrate 30 and a deposition layer 31 having a scintillator 8 are bonded is within a predetermined allowable amount allowing the influence on the radiation images.

Description

  The present invention relates to a radiation imaging apparatus.

  2. Description of the Related Art In recent years, radiation detectors such as FPD (Flat Panel Detector) capable of directly converting radiation such as X-rays into digital data by arranging a radiation sensitive layer on a TFT (Thin Film Transistor) active matrix substrate have been put into practical use. The radiography apparatus using this radiation detector can see images immediately, compared with conventional radiography apparatuses using X-ray film or imaging plate, and radiographic imaging (moving image) (Photographing) can also be performed.

  Various types of radiation detectors of this type have been proposed. For example, radiation is once converted into light by a scintillator such as CsI: Tl or GOS (Gd2O2S: Tb), and the converted light is a photodiode or the like. There is an indirect conversion method in which the sensor unit converts the charges into charges. In the radiation imaging apparatus, the electric charge accumulated in the radiation detector is read as an electric signal, and the read electric signal is amplified by an amplifier and then converted into digital data by an A / D (analog / digital) converter.

  By the way, the radiation detector may be warped due to a temperature change. For example, the indirect conversion type radiation detector has a coefficient of thermal expansion between the TFT substrate and the vapor deposition substrate when the TFT substrate on which the TFT is formed and the vapor deposition substrate on which the scintillator is formed by vapor deposition of CsI or the like are bonded together. Due to the difference, warping occurs due to temperature change.

  As a technique for suppressing the warpage of the radiation detector, Patent Document 1 discloses a radiation imaging in which a fluorescent plate made of a phosphor base / phosphor / phosphor protective layer is bonded to a photosensor from the phosphor protective layer surface side. In the apparatus, a technique is disclosed in which a fluorescent plate is bonded to an optical sensor and then a phosphor base is cut.

  Further, in Patent Document 2, the power consumption immediately after power-on is changed to the internal temperature by energizing a heater arranged in the radiation imaging apparatus, changing the drive frequency of the circuit, or changing the power supply voltage of the circuit. There has been proposed a technique for shortening the time until the internal temperature becomes stable by making the value larger than that in a stable steady state.

JP 2003-270352 A JP 2009-292974 A

  However, although the technique of Patent Document 1 can suppress the occurrence of warping of the radiation detector, the radiation detector is warped due to a temperature change, and the captured radiographic image is affected.

  In addition, although the technique of Patent Document 2 can shorten the time until the temperature in the radiation imaging apparatus is stabilized, the radiation detector may be warped in a state where the temperature is stable, and radiation to be imaged. The image will be affected.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a radiation imaging apparatus capable of capturing a radiation image while suppressing the influence of warping.

  In order to achieve the above object, a radiation imaging apparatus according to claim 1 is formed by bonding two flat substrates having different coefficients of thermal expansion to each other, and an imaging panel for capturing a radiation image, and the imaging Temperature adjusting means for adjusting the temperature of the panel, and a temperature at which the imaging panel includes a temperature at the time of bonding of the two substrates, and warping of the imaging panel due to a temperature change is allowed to have an influence on a radiographic image Control means for controlling the temperature adjusting means so as to be within a temperature range within an allowable amount.

  According to the present invention, two plate-like substrates having different thermal expansion coefficients are bonded together to form an imaging panel, and a radiographic image is taken by the imaging panel. The panel temperature is adjustable.

  Then, by the control means, the temperature of the imaging panel includes a temperature at the time of bonding of the two substrates, and the warping of the imaging panel due to the temperature change is within a predetermined allowable amount in which the influence on the radiation image is allowed. The temperature adjusting means is controlled so that

Thus, according to the first aspect of the invention, the temperature of the imaging panel includes the temperature at the time of bonding of the two substrates, and the warp of the imaging panel due to the temperature change is allowed to have an influence on the radiation image. Since the warping of the imaging panel is suppressed within the allowable amount, the radiation image can be captured while suppressing the influence of the warping. As in the invention described in (1), the apparatus further includes a housing that accommodates the imaging panel, and the control unit is configured to be within a temperature range in which the warping of the imaging panel is within the allowable amount when radiographic images are captured. The temperature adjusting unit may be controlled to control the temperature adjusting unit so that the warp of the photographing panel does not contact the housing and falls within a temperature range within the housing when not photographing. .

  Further, according to the present invention, as in the invention described in claim 3, when the control unit performs radiographic image capturing, the temperature of the imaging panel is within a temperature range in which the warp of the imaging panel is within the allowable amount. If it is within the range, control for permitting photographing may be performed.

  Further, according to the present invention, as in the invention described in claim 4, one of the two substrates is a substrate on which a scintillator that converts incident radiation into light is formed, and the other is light converted by the scintillator. It is preferable that the substrate has a sensor portion for detecting

  Further, according to the present invention, as in the invention described in claim 5, the photographing panel is formed so that a warpage amount is within the allowable amount near an upper limit or a lower limit of a usable temperature range usable for photographing. Also good.

  According to a fifth aspect of the present invention, as in the sixth aspect of the present invention, the photographing panel has a warpage amount within the allowable amount near an upper limit of the operating temperature range, and the temperature adjusting means is It may be a heating means for heating the imaging panel.

  According to a fifth aspect of the present invention, as in the seventh aspect of the present invention, the photographing panel has a warpage amount within the allowable amount near a lower limit of the operating temperature range, and the temperature adjusting means is A cooling means for cooling the imaging panel may be used.

  In the present invention, as in the invention described in claim 8, at least one of the two substrates may be formed of any one of plastic resin, aramid, bionanofiber, and a flexible glass substrate. .

  The radiation imaging apparatus of the present invention has an excellent effect that radiographic images can be captured while suppressing the influence of warpage.

It is sectional drawing which showed typically the structure of the radiation detector which concerns on embodiment. It is sectional drawing which showed the structure of the thin-film transistor and capacitor | condenser of the radiation detector which concern on embodiment. It is a top view which shows the structure of the radiation detector which concerns on embodiment. It is a perspective view which shows the structure of the electronic cassette concerning embodiment. It is sectional drawing which shows the structure of the electronic cassette concerning embodiment. It is a top view which shows arrangement | positioning of the connector provided in the radiation detector which concerns on embodiment. It is a block diagram which shows the principal part structure of the electric system of the electronic cassette concerning embodiment. It is a graph which shows the relationship between the temperature change of the radiation detector which concerns on embodiment, and the amount of curvature. (A) And (B) is sectional drawing which shows the state along which the radiation detector which concerns on embodiment followed. It is sectional drawing which shows the state which has arrange | positioned the temperature sensor and the temperature adjustment part to the radiation detector which concerns on embodiment. It is a flowchart which shows the flow of a process of the temperature control switching process program which concerns on 2nd Embodiment. It is a graph which shows the relationship between the temperature change of the radiation detector which concerns on 3rd Embodiment, and curvature amount. It is sectional drawing which shows the state which has arrange | positioned the temperature sensor and the heater to the radiation detector which concerns on 3rd Embodiment. It is sectional drawing which shows the state which has arrange | positioned the temperature sensor and the temperature adjustment part, or the heater to the radiation detector which concerns on another form. It is a graph which shows the relationship between the temperature change and curvature amount of the radiation detector which concerns on other embodiment. It is sectional drawing which shows the state which has arrange | positioned the temperature sensor and the cooling mechanism to the radiation detector which concerns on another form.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. Here, a radiographic image obtained by imaging a radiographic image using a portable radiographic imaging device (hereinafter also referred to as “electronic cassette”) that captures a radiographic image represented by radiation irradiated using a radiation detector. An example in which the present invention is applied to a photographing system will be described.
[First Embodiment]
First, the configuration of the radiation detector 20 according to the present embodiment will be described.

  FIG. 1 is a cross-sectional view schematically showing the configuration of the radiation detector 20 according to the present embodiment, and FIG. 2 is a plan view showing the configuration of the radiation detector 20. .

  As shown in FIG. 1, the radiation detector 20 includes a TFT active matrix substrate (hereinafter referred to as “TFT substrate”) 30 in which a thin film transistor (TFT) 10 and a capacitor 9 are formed on an insulating substrate 1. I have.

  A scintillator 8 that converts incident radiation into light is disposed on the TFT substrate 30.

As the scintillator 8, for example, CsI: Tl, GOS (Gd ₂ O ₂ S: Tb) can be used. The scintillator 8 is not limited to these materials.

  The insulating substrate 1 may be any substrate as long as it is light transmissive and absorbs little radiation. For example, a glass substrate, a transparent ceramic substrate, or a light transmissive resin substrate can be used. The insulating substrate 1 is not limited to these materials.

  The TFT substrate 30 is formed with a sensor unit 13 that generates charges when light converted by the scintillator 8 is incident thereon. Further, a planarizing layer 5 for planarizing the TFT substrate 30 is formed on the TFT substrate 30. An adhesive layer 7 for bonding the scintillator 8 to the TFT substrate 30 is formed between the TFT substrate 30 and the scintillator 8 and on the planarizing layer 5.

  The sensor unit 13 includes an upper electrode 6, a lower electrode 2, and a photoelectric conversion film 4 disposed between the upper and lower electrodes.

  The photoelectric conversion film 4 absorbs light emitted from the scintillator 8 and generates electric charges according to the absorbed light. The photoelectric conversion film 4 may be formed of a material that generates charges when irradiated with light. For example, the photoelectric conversion film 4 can be formed of amorphous silicon, an organic photoelectric conversion material, or the like. The photoelectric conversion film 4 containing amorphous silicon has a wide absorption spectrum and can absorb light emitted by the scintillator 8. If the photoelectric conversion film 4 includes an organic photoelectric conversion material, it has a sharp absorption spectrum in the visible range, and electromagnetic waves other than light emitted by the scintillator 8 are hardly absorbed by the photoelectric conversion film 4, and radiation such as X-rays. Can be effectively suppressed noise generated by the absorption by the photoelectric conversion film 4.

  In the present embodiment, the photoelectric conversion film 4 includes an organic photoelectric conversion material. Examples of the organic photoelectric conversion material include quinacridone organic compounds and phthalocyanine organic compounds. For example, since the absorption peak wavelength in the visible region of quinacridone is 560 nm, if quinacridone is used as the organic photoelectric conversion material and CsI (Ti) is used as the material of the scintillator 8, the difference in peak wavelength can be made within 5 nm. Thus, the amount of charge generated in the photoelectric conversion film 4 can be substantially maximized. Since an organic photoelectric conversion material applicable as the photoelectric conversion film 4 is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

  FIG. 2 schematically shows the configuration of the thin film transistor 10 and the capacitor 9.

  On the insulating substrate 1, a capacitor 9 that accumulates the charges transferred to the lower electrode 2 corresponding to the lower electrode 2, and a thin film transistor 10 that converts the charges accumulated in the capacitor 9 into an electric signal and outputs the electric signal is formed. Has been. The region in which the capacitor 9 and the thin film transistor 10 are formed has a portion that overlaps the lower electrode 2 in plan view. With such a configuration, the capacitor 9 and the thin film transistor 10 in each pixel unit, the sensor unit 13, Will have an overlap in the thickness direction. In order to minimize the plane area of the radiation detector 20 (pixel portion), it is desirable that the region where the capacitor 9 and the thin film transistor 10 are formed is completely covered by the lower electrode 2.

  The capacitor 9 is electrically connected to the corresponding lower electrode 2 through a wiring made of a conductive material formed through an insulating film 11 provided between the insulating substrate 1 and the lower electrode 2. . Thereby, the electric charge collected by the lower electrode 2 can be moved to the capacitor 9.

In the thin film transistor 10, a gate electrode 15, a gate insulating film 16, and an active layer (channel layer) 17 are stacked, and a source electrode 18 and a drain electrode 19 are formed on the active layer 17 at a predetermined interval. . In the radiation detector 20, the active layer 17 is formed of an amorphous oxide. The amorphous oxide constituting the active layer 17 is preferably an oxide containing at least one of In, Ga, and Zn (for example, In—O-based), and at least two of In, Ga, and Zn. An oxide containing In (for example, In—Zn—O, In—Ga, or Ga—Zn—O) is more preferable, and an oxide containing In, Ga, and Zn is particularly preferable. As the In—Ga—Zn—O-based amorphous oxide, an amorphous oxide whose composition in a crystalline state is represented by InGaO ₃ (ZnO) _m (m is a natural number less than 6) is preferable, and InGaZnO is particularly preferable. ₄ is more preferable.

  If the active layer 17 of the thin film transistor 10 is formed of an amorphous oxide, it does not absorb radiation such as X-rays, or even if it is absorbed, it remains extremely small, so that the generation of noise is effectively suppressed. be able to.

  Here, both the amorphous oxide constituting the active layer 17 of the thin film transistor 10 and the organic photoelectric conversion material constituting the photoelectric conversion film 4 can be formed at a low temperature. Therefore, the insulating substrate 1 is not limited to a substrate having high heat resistance such as a semiconductor substrate, a quartz substrate, and a glass substrate, and a flexible substrate such as plastic, aramid, or bio-nanofiber can also be used. Specifically, flexible materials such as polyesters such as polyethylene terephthalate, polybutylene phthalate, polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, poly (chlorotrifluoroethylene), etc. A conductive substrate can be used. If such a plastic flexible substrate is used, it is possible to reduce the weight, which is advantageous for carrying around, for example. The insulating substrate 1 includes an insulating layer for ensuring insulation, a gas barrier layer for preventing permeation of moisture and oxygen, an undercoat layer for improving flatness or adhesion to electrodes, etc. May be provided.

  Since aramid can be applied at a high temperature process of 200 ° C. or more, the transparent electrode material can be cured at a high temperature to reduce the resistance, and can also be used for automatic mounting of a driver IC including a solder reflow process. Moreover, since aramid has a thermal expansion coefficient close to that of ITO (indium tin oxide) or a glass substrate, warping after production is small and it is difficult to crack. In addition, aramid can form a substrate thinner than a glass substrate or the like. The insulating substrate 1 may be formed by laminating an ultrathin glass substrate and aramid.

  Bionanofiber is a composite of cellulose microfibril bundles (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 insulating substrate 1 can be formed.

  As shown in FIG. 3, the TFT substrate 30 includes pixels 32 including the sensor unit 13, the capacitor 9, and the thin film transistor 10 described above. A plurality of two-dimensional shapes are provided (in the column direction in FIG. 3).

  Further, the radiation detector 20 has a plurality of gate wirings 34 extending in a certain direction (row direction) for turning on / off each thin film transistor 10 and a crossing direction (column direction) extending in an on state. A plurality of data wirings 36 for reading out charges through the thin film transistor 10 are provided.

  The radiation detector 20 is flat and has a quadrilateral shape with four sides at the outer edge in plan view. Specifically, it is formed in a rectangular shape.

  In the radiation detector 20 according to this embodiment, the scintillator 8 is formed on the surface of the TFT substrate 30 as shown in FIG.

  For example, the scintillator 8 is formed by vapor deposition on the vapor deposition substrate 31 when it is intended to be formed of a columnar crystal such as CsI: Tl. Thus, when the scintillator 8 is formed by vapor deposition, the vapor deposition substrate 31 is often an Al plate in terms of X-ray transmittance and cost, handling properties during vapor deposition, prevention of warpage due to its own weight, and deformation due to radiant heat. Therefore, a certain thickness (about several mm) is required.

  The radiation detector 20 is formed by attaching a vapor deposition substrate 31 on which the scintillator 8 is formed on the TFT substrate 30 using an adhesive resin having low light absorption. Specifically, the TFT substrate 30 and the vapor deposition substrate 31 on which the scintillator 8 is formed are placed in a constant temperature bath, and the TFT substrate 30 and the scintillator 8 are bonded together in a state where the environment such as temperature is controlled.

  Next, the configuration of a portable radiation imaging apparatus (hereinafter referred to as an electronic cassette) 40 that incorporates such a radiation detector 20 and captures a radiation image will be described.

  4 is a perspective view showing the configuration of the electronic cassette 40, and FIG. 5 is a cross-sectional view of the electronic cassette 40. As shown in FIG.

  The electronic cassette 40 includes a flat housing 41 made of a material that transmits radiation, and has a waterproof and airtight structure. In the electronic cassette 40, a control board 42 in which a radiation detector 20 and various control integrated circuits are provided in a housing 41 is sequentially provided. In the case 41, an area corresponding to the arrangement position of the radiation detector 20 on one flat surface is an imaging area 41A to which the radiation is irradiated during imaging.

  As shown in FIG. 5, a flat base 64 is provided inside the housing 41. The base 64 is fixed to the housing 41 by support legs 64. The radiation detector 20 is disposed on the surface of the base 64 on the imaging region 41A side, and the control board 42 is disposed on the surface of the base 64 opposite to the imaging region 41A.

  As shown in FIG. 6, the radiation detector 20 is provided with a plurality of connection connectors 33 arranged at one end side in the direction of the data wiring 36 and a plurality of connectors 35 arranged at one end side in the direction of the gate wiring 34. It has been. Each signal wiring 24 is connected to a connector 33, and each scanning wiring 22 is connected to a connector 35.

  One end of a flexible cable 44 is electrically connected to the connector 33, and one end of a flexible cable 45 is electrically connected to the connector 35.

  The control board 42 is provided with a plurality of connectors 46 and 48, the other end of the flexible cable 44 is electrically connected to the connector 46, and the other end of the flexible cable 45 is electrically connected to the connector 48. It is connected.

  The control board 42 is provided with a gate line driver 52, a signal processing unit 54, an image memory 56, a cassette control unit 58, a wireless communication unit 60, and the like, which will be described later.

  FIG. 7 is a block diagram showing a main configuration of the electric system of the electronic cassette 40 according to the present exemplary embodiment.

  Each gate wiring 34 of the TFT substrate 30 is connected to the gate line driver 52 via the flexible cable 45, and each data wiring 36 of the TFT substrate 30 is connected to the signal processing unit 54 via the flexible cable 44. Yes.

  Each thin film transistor 10 of the TFT substrate 30 is sequentially turned on in a row unit by a signal supplied from the gate line driver 52 via the gate wiring 34, and the electric charge read by the thin film transistor 10 in the on state is converted into an electric signal. The data wiring 36 is transmitted and input to the signal processing unit 54. As a result, the charges are sequentially read out in units of rows, and a two-dimensional radiation image can be acquired.

  Although not shown, the signal processing unit 54 includes an amplification circuit and a sample hold circuit for amplifying an input electric signal for each data wiring 36, and the electric signal transmitted through the individual data wiring 36. Is amplified by the amplifier circuit and then held in the sample hold circuit. Further, a multiplexer and an A / D (analog / digital) converter are connected in order to the output side of the sample and hold circuit, and the electric 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 56 is connected to the signal processing unit 54, and image data output from the A / D converter of the signal processing unit 54 is sequentially stored in the image memory 56. The image memory 56 has a storage capacity capable of storing a predetermined number of image data, and image data obtained by imaging is sequentially stored in the image memory 56 each time a radiographic image is captured.

  The image memory 56 is connected to the cassette control unit 58. The cassette control unit 58 includes a microcomputer (CPU) 58A, a memory 58B including a ROM and a RAM, a nonvolatile storage unit 58C including a flash memory, and the like, and operates the entire electronic cassette 40. Control.

  A wireless communication unit 60 is connected to the cassette control unit 58. The wireless communication unit 60 corresponds to a wireless local area network (LAN) standard represented by IEEE (Institute of Electrical and Electronics Engineers) 802.11a / b / g, etc. Control transmission of various information. The cassette control unit 58 can wirelessly communicate with an external device such as a console for controlling the entire radiation imaging via the wireless communication unit 60, and can transmit and receive various types of information to and from the console.

  In addition, the electronic cassette 40 is provided with a power supply unit 70, which functions as the above-described various circuits and elements (gate line driver 52, signal processing unit 54, image memory 56, wireless communication unit 60, and cassette control unit 58). The microcomputer that operates is operated by the power supplied from the power supply unit 70. The power supply unit 70 incorporates a battery (a rechargeable secondary battery) so as not to impair the portability of the electronic cassette 40, and supplies power from the charged battery to various circuits and elements. In FIG. 7, the power supply unit 70, various circuits, and wirings for connecting each element are omitted.

  The cassette control unit 58 controls the operation of the gate line driver 52 and can control reading of image information indicating a radiation image from the TFT substrate 30.

  Incidentally, the radiation detector 20 may be warped as shown in FIG. 8 due to a temperature change due to a difference in thermal expansion coefficient between the insulating substrate 1 and the vapor deposition substrate 31.

  For example, when the insulating substrate 1 is made of glass having a thickness of 0.7 mm and a thermal expansion coefficient of 3 ppm, and the vapor deposition substrate 31 is made of Al having a thickness of 0.5 to 0.7 mm and a thermal expansion coefficient of 30 ppm, the temperature is low. In the case of FIG. 9A, the insulating substrate 1 side warps so as to be convex, and in the case of a high temperature, the deposition substrate 31 side warps as shown in FIG. 9B. .

  Therefore, the electronic cassette 40 according to the present exemplary embodiment captures a radiographic image while suppressing the warp of the radiation detector 20, and therefore, as shown in FIG. 10, a temperature sensor 80 that detects the temperature on the radiation detector 20, In addition, a temperature adjustment unit 82 that adjusts the temperature of the radiation detector 20 is provided so as to overlap almost the entire surface of the radiation detector 20.

  For example, when the temperature adjusting unit 82 is configured by a Peltier element, the radiation detector 20 can be heated and cooled by changing the direction of a current flowing between two types of metals that configure the Peltier element. Note that a heater or a cooling mechanism may be provided as the temperature adjustment unit 82 to heat and cool the radiation detector 20. When the radiation detector 20 is formed by attaching the TFT substrate 30 and the vapor deposition substrate 31, the temperature adjustment unit 82 is preferably provided on at least the substrate side having a higher coefficient of thermal expansion.

  The temperature sensor 80 and the temperature adjustment unit 82 are connected to a cassette control unit 58 as shown in FIG. The cassette control unit 58 can grasp the temperature detected by the temperature sensor 80. The cassette control unit 58 can control the temperature of the radiation detector 20 by heating or cooling the radiation detector 20 by the temperature adjustment unit 82.

  By the way, as described above, the radiation detector 20 is formed by bonding the TFT substrate 30 and the vapor deposition substrate 31 in a constant temperature bath. However, the radiation detector 20 is bonded after stabilizing the expansion change of the TFT substrate 30 and the vapor deposition substrate 31. Thus, it can be formed with almost no warping at the time of bonding. For example, when the inside of the thermostatic chamber is set to 18 ° C., the TFT substrate 30 and the vapor deposition substrate 31 are bonded together, so that there is almost no warpage around 18 ° C. as shown in FIG.

  In the present embodiment, the storage unit 58C of the cassette control unit 58 includes a temperature at the time of bonding of the vapor deposition substrate 31 and the TFT substrate 30, and the warp of the radiation detector 20 is allowed to have a predetermined permission that is allowed to affect the radiation image. A predetermined temperature range HA within the capacity X is stored, and the cassette control unit 58 controls the temperature adjustment unit 82 so that the temperature of the radiation detector 20 falls within the temperature range HA.

  As described above, according to the present embodiment, the radiation image can be taken while suppressing the influence of the warp by controlling the temperature range HA to include the temperature at the time of bonding the vapor deposition substrate 31 and the TFT substrate 30.

[Second Embodiment]
Next, a second embodiment will be described.

  Since the configurations of the radiation detector 20 and the electronic cassette 40 according to the second embodiment are the same as those of the first embodiment (see FIGS. 1 to 10), description thereof is omitted here.

  By the way, a cassette having a built-in film and an imaging plate has an outer size standard defined in JIS (Japanese Industrial Standard) Z4905. In order to use the electronic cassette 40 by replacing it with a cassette incorporating a film or an imaging plate, it is necessary to satisfy the outer size of JIS Z4905, and the thickness needs to be 14 mm (± 1 mm) or less. In some cases, the electronic cassette 40 is inserted into the lower part of the body of a lying patient to perform imaging, and the thinner one is easier to handle.

  However, it is difficult for the electronic cassette 40 to be raised in advance so that the radiation detector 20 does not come into contact with the housing 41 when the radiation detector 20 warps as the thickness becomes thinner.

  On the other hand, the electronic cassette 40 is not affected even if the radiation detector 20 is warped as long as it does not contact the casing 41 during standby when no image is taken.

  Therefore, in the present embodiment, the allowable amount of warpage is changed between standby and radiographic image capturing. Specifically, in the storage unit 58C of the cassette control unit 58, the warp of the radiation detector 20 does not come into contact with the casing 41 in the storage unit 58C of the cassette control unit 58, and is within the range (the warp in FIG. 8). The temperature range HB in which the amount is in the range of + Y to -Y) is stored as the standby temperature range, and the temperature range HA in which the warp of the radiation detector 20 is within a predetermined allowable amount X in which the influence on the radiation image is allowed It is stored as a shooting temperature range. The cassette control unit 58 controls the temperature of the radiation detector 20 to be in the waiting temperature range during standby, and controls the temperature of the radiation detector 20 to be within the imaging temperature range during imaging.

  In the electronic cassette 40 according to the present embodiment, when a radiographic image is captured, an instruction to switch to the imaging temperature range is notified from a control device (so-called console) that controls radiographic image capturing.

  After the activation, the cassette control unit 58 controls the temperature adjustment unit 82 so that the radiation detector 20 is within the standby temperature range, and when the switching instruction to the imaging temperature range is notified from the console, the radiation detector 20. Is switched so that the temperature is within the imaging temperature range, and imaging permission is notified to the console when the temperature of the radiation detector 20 is within the imaging temperature range. Then, the cassette control unit 58 switches the control of the temperature adjustment unit 82 so that the radiation detector 20 is within the imaging temperature range after the imaging is completed.

  FIG. 11 shows a flowchart showing the flow of the temperature control switching processing program executed by the CPU 58A when an instruction to switch to the photographing temperature range is notified from the console. The program is stored in advance in a predetermined area of the ROM of the memory 58.

  In step S10, control of the temperature adjustment unit 82 is started so that the radiation detector 20 is within the imaging temperature range.

  In the next step S12, it is determined whether or not the temperature of the radiation detector 20 is within the imaging temperature range. If the determination is affirmative, the process proceeds to step S14. If the determination is negative, the process returns to step S12. The process waits until the temperature of the radiation detector 20 falls within the imaging temperature range.

  In step S14, the photographing permission is notified to the console.

  Thereby, the radiographic image is taken.

  In the next step S16, it is determined whether or not the radiographic image capturing has been completed. If the determination is affirmative, the process proceeds to step S18. If the determination is negative, the process proceeds to step S16 again to complete the imaging. Wait.

  In step S18, control of the temperature adjustment unit 82 is started so that the radiation detector 20 is within the standby temperature range, and the process is terminated.

  As described above, according to the present embodiment, it is possible to capture a radiographic image while suppressing the influence of warping by controlling the temperature range HA during imaging.

  Further, according to the present embodiment, at the time of standby, the curvature of the radiation detector 20 is not brought into contact with the housing 41, and is switched to the temperature range HB that is within the housing, so that the range becomes as narrow as the time of photographing. Since there is no need for temperature control, power consumption for temperature control can be suppressed.

[Third Embodiment]
Next, a third embodiment will be described.

  Since the configurations of the radiation detector 20 and the electronic cassette 40 according to the third embodiment are the same as those of the first embodiment (see FIGS. 1 to 10), description thereof is omitted here.

  By the way, the electronic cassette 40 may be photographed in contact with a patient. Further, the electronic cassette 40 generates noise or the like in an electronic device built in depending on the temperature. For this reason, as for the electronic cassette 40, the use temperature range which can be used by imaging | photography is defined (for example, 10 to 40 degreeC).

  In the present embodiment, as shown in FIG. 12, the radiation detector 20 is warped near the upper limit of the operating temperature range so that the curvature of the radiation detector 20 is within an allowable amount X that is allowed to affect the radiation image. Is formed. Specifically, when the TFT substrate 30 and the vapor deposition substrate 31 are bonded together, the temperature in the thermostatic chamber is set to a temperature near the upper limit of the use temperature range, so that there is almost no warpage near the upper limit of the use temperature range. Forming.

  In addition, the electronic cassette 40 according to the present exemplary embodiment is provided with a heater 82 </ b> A that heats the radiation detector 20 as a temperature adjustment unit 82 as a mechanism for adjusting the temperature of the radiation detector 20.

  The storage unit 58C of the cassette control unit 58 stores a temperature range HC in which the amount of warpage of the radiation detector 20 is within the allowable amount X within the operating temperature range. The heater 82A is controlled so that the temperature of the vessel 20 falls within the temperature range HC.

  As described above, according to the present embodiment, the radiation detector 20 is formed so that the amount of warpage becomes the allowable amount X near the upper limit of the usable temperature range, and is heated by the heater 82A to be the temperature of the radiation detector 20. By controlling the temperature of the radiation detector 20 so as to be in the temperature range HC, it is possible to capture a radiation image while suppressing the influence of warping.

  Further, according to the present embodiment, when the amount of warpage of the radiation detector 20 is controlled within the allowable amount X, it is not necessary to cool the radiation detector 20 and only heating is required. The configuration of 82 can be simplified.

  As mentioned above, although this invention was demonstrated using the 1st-3rd embodiment, not only each embodiment mentioned above is implemented independently, but you may combine each embodiment suitably. The technical scope of the present invention is not limited to the scope described in the above embodiment. Various modifications or improvements can be added to the above-described embodiment without departing from the gist of the invention, and embodiments to which such modifications or improvements are added are also included in the technical scope of the present invention. For example, in the third embodiment, similarly to the second embodiment, the temperature range of the radiation detector 20 is set to a standby temperature range in which the warp of the radiation detector 20 does not contact the housing 41 during standby, You may make it control to the imaging | photography temperature range from which the curvature of the radiation detector 20 becomes less than the tolerance | permissible_quantity X at the time of imaging | photography.

  In each of the above embodiments, the case where the present invention is applied to the electronic cassette 40 which is a portable radiation imaging apparatus has been described. However, the present invention is not limited to this, and a stationary radiation imaging apparatus is provided. You may apply to.

  Further, in each of the above-described embodiments, the case where the temperature adjustment unit 82 or the heater 82A is provided on almost the entire surface of the radiation detector 20 as shown in FIGS. 10 and 13 is described, but the present invention is not limited to this. . For example, as shown in FIG. 14, a heat conductive sheet 83 may be disposed on almost the entire surface of the radiation detector 20, and the temperature adjustment unit 82 may perform cooling or heating via the heat conductive sheet 83.

  Further, in the third embodiment, the radiation detector 20 is formed so that the amount of warpage becomes an allowable amount near the upper limit of the usable temperature range, and the amount of warpage of the radiation detector 20 is controlled by heating. However, the present invention is not limited to this. For example, as shown in FIG. 15, the radiation detector 20 is formed so that the amount of warpage becomes an allowable amount X near the lower limit of the usable temperature range, and as shown in FIG. A cooling mechanism 82B may be provided on the entire surface, and the radiation detector 20 may be cooled to a temperature range HD in which the amount of warpage of the radiation detector 20 is within the allowable amount X within the operating temperature range by cooling.

  Thus, by forming the radiation detector 20 so that the amount of warpage becomes an allowable amount X near the upper or lower limit of the usable temperature range, either the heating by the heater or the cooling by the cooling mechanism 82B is stored. It becomes possible to cope with temperature. For example, when shooting is mainly performed in a cold district, the cassette for cold district specification can be manufactured by lowering the affixing temperature.

  As described above, the radiation detector 20 can be formed in a state where there is almost no warping at the time of bonding by bonding after stabilizing the expansion change of the TFT substrate 30 and the vapor deposition substrate 31 in the thermostat. For this reason, considering the usage environment of the electronic cassette 40 (when considering use overseas, the average temperature in the country where it is used, the medical situation (whether the hospital has air conditioning, etc.), etc.) The temperature at the time of bonding may be changed in accordance with, for example, the average temperature of the usage environment of the electronic cassette 40 may be set as the temperature at the time of bonding. Thereby, in order to suppress the curvature of the radiation detector 20, the necessity to perform heating or cooling can be suppressed.

DESCRIPTION OF SYMBOLS 1 Insulating board 8 Scintillator 13 Sensor part 20 Radiation detector (imaging panel)
30 TFT substrate 31 Vapor deposition substrate 40 Electronic cassette 41 Case 42 Control substrate 58 Cassette control unit 58A CPU
58B Memory 58C Storage part 80 Temperature sensor 82 Temperature adjustment part (Temperature adjustment means)
82A heater (heating means)
82B Cooling mechanism (cooling means)
83 Thermally conductive sheet

Claims (8)

An imaging panel that is formed by laminating two flat substrates having different thermal expansion coefficients, and that captures radiographic images;
Temperature adjusting means for adjusting the temperature of the photographing panel;
The temperature of the imaging panel includes a temperature at the time of bonding of the two substrates, and the warp of the imaging panel due to the temperature change is within a predetermined allowable range in which the influence on the radiation image is allowed. Control means for controlling the temperature adjusting means;
A radiography apparatus comprising: A housing for accommodating the photographing panel;
The control means controls the temperature adjusting means so that the curvature of the imaging panel is within the allowable range when capturing a radiographic image, and the curvature of the imaging panel is a case when not capturing. The radiation imaging apparatus according to claim 1, wherein the temperature adjusting unit is controlled so as to be within a temperature range that is within a range that does not abut on the housing and is within a housing. The said control means performs control which permits imaging | photography, when the temperature of the said imaging panel is in the temperature range in which the curvature of the said imaging panel becomes less than the said allowable amount when imaging | photography of a radiographic image. Item 3. The radiographic apparatus according to Item 2. The one of the two substrates is a substrate on which a scintillator that converts incident radiation into light is formed, and the other is a substrate on which a sensor unit that detects light converted by the scintillator is formed. Item 4. The radiographic apparatus according to any one of Items3. The radiographic apparatus according to any one of claims 1 to 4, wherein the imaging panel is formed such that a warpage amount is within the allowable amount near an upper limit or a lower limit of a usable temperature range usable for imaging. . The photographing panel has a warpage amount within the allowable amount near the upper limit of the operating temperature range,
The radiation imaging apparatus according to claim 5, wherein the temperature adjusting unit is a heating unit that heats the imaging panel. The photographing panel has a warpage amount within the allowable amount near the lower limit of the operating temperature range,
The radiation imaging apparatus according to claim 5, wherein the temperature adjustment unit is a cooling unit that cools the imaging panel. The radiation imaging apparatus according to claim 3, wherein at least one of the two substrates is made of any one of a plastic resin, an aramid, a bionanofiber, and a flexible glass substrate.

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