WO2013065645A1 - Radiological imaging device, program and radiological imaging method - Google Patents

Abstract

Provided are a radiological imaging device, program and radiological imaging method with which the irradiation state of radiation can be detected with high precision. When a first thin-film transistor (TFT) substrate is used to capture still images, the irradiation state of radiation is detected on the basis of charges read by a second TFT substrate provided for capturing video.

Description

Radiographic imaging apparatus, program, and radiographic imaging method

The present invention relates to a radiographic image capturing apparatus, a program, and a radiographic image capturing method, and more particularly to a radiographic image capturing apparatus, a program, and a radiographic image capturing method for capturing a radiographic image indicated by radiation transmitted through a subject.

Recently, radiation detectors such as FPD (Flat Panel Detector) that can directly convert 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 radiographic imaging device using this radiation detector can see images immediately and can continuously capture radiographic images as compared with conventional radiographic imaging devices using X-ray film or imaging plate. There is an advantage that (moving image shooting) 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, GOS (Gd ₂ O ₂ S: Tb), and converted light. There is an indirect conversion method in which a sensor unit such as a photodiode converts it into electric charge and stores it. In the radiographic 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, in this type of radiographic imaging apparatus, if the radiographic imaging apparatus itself can detect the irradiation state such as the start and stop of irradiation and the irradiation amount, the radiographic imaging apparatus and the radiation source are integrated. Therefore, it is not necessary to connect the imaging control device to be controlled to the radiation source, which is preferable in simplifying the system configuration and simplifying the control by the imaging control device.

As a technique related to a radiographic imaging apparatus capable of detecting the irradiation state of this type of radiation, Japanese Patent No. 4217443 discloses a phosphor that converts incident radiation into visible light, and converts the visible light into an electrical signal. Including a pixel area including a plurality of pixels on a substrate including a first photoelectric conversion element that performs switching and a switching element that switches an output operation of an electric signal from the first photoelectric conversion element. A radiographic imaging apparatus in which image information is generated based on an electrical signal output from an element, comprising a second photoelectric conversion element for detecting an incident amount of the radiation, the switching element and the first The radiation image capturing apparatus is characterized in that the second photoelectric conversion element is disposed between the substrate and the first photoelectric conversion element in the pixel area. It is.

Japanese Patent No. 4217506 has a conversion unit including a plurality of pixels each having a first conversion element on the side on which radiation of the substrate is incident, and outputs image information according to the amount of radiation incident on the conversion unit. A radiation imaging apparatus for detecting a second conversion element for detecting at least one of an irradiation amount of radiation incident in the conversion unit, incidence of radiation into the conversion unit, and stop of radiation. The second conversion element has a width smaller than the pitch of the pixels between the first conversion elements of adjacent pixels in the conversion unit on the side of the substrate on which radiation is incident. A radiation imaging apparatus characterized by being arranged in a shape is disclosed.

However, the techniques disclosed in Japanese Patent Nos. 4217443 and 4217506 have a problem that the irradiation state of radiation cannot always be accurately detected.

That is, when taking a still image of a radiographic image, in order to reduce the exposure dose to the subject as much as possible, imaging is often performed only on the region of interest of the subject. A collimator is used to narrow down the irradiation area to be only the area of interest.

In this case, in the techniques disclosed in the above Patent Nos. 4217443 and 4217506, the radiation detector for capturing the radiation image is provided with a sensor for detecting the irradiation state of the radiation. As a result of a sensor that can be used to detect the irradiation state being narrowed by the collimator, it is not always possible to detect the irradiation state of radiation with high accuracy.

Note that the problem of narrowing the radiation irradiation area with this collimator is that the radiation irradiation state is detected according to the change in the bias voltage applied to the sensor section of the radiation detector, and the leakage from each pixel. This is a problem that may occur even in the form of detecting the irradiation state of radiation based on a change in current.

In addition, a technique that uses a part of the radiographic image capturing pixels to detect the irradiation state of the radiation is also conceivable. However, in this technique, defective pixels are generated in the radiographic image obtained by imaging. Too many pixels cannot be used for detecting the radiation irradiation state, and even with this technique, the radiation irradiation state cannot always be detected with high accuracy.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a radiographic image capturing apparatus, a program, and a radiographic image capturing method capable of detecting a radiation irradiation state with high accuracy. .

The radiographic imaging device according to the first aspect of the present invention includes a radiation-sensitive layer that generates light corresponding to irradiated radiation or generates a charge corresponding to irradiated radiation, and is laminated on the radiation-sensitive layer. A first photoelectric conversion unit that generates a charge corresponding to the light when the radiation sensitive layer generates light, and a first switching element for reading out the charge generated by the first photoelectric conversion unit. A plurality of first pixels are provided in a matrix, or a plurality of second pixels provided with a second switching element for reading out the charges when the radiation sensitive layer generates charges are provided in a matrix A first substrate for still image shooting and a layer opposite to the first substrate of the radiation sensitive layer are stacked, and when the radiation sensitive layer generates light, a charge corresponding to the light is generated. A plurality of third pixels having a second photoelectric conversion unit and a third switching element for reading out the electric charge generated by the second photoelectric conversion unit are provided in a matrix, or the radiation-sensitive layer has a charge. A radiation detector having a second substrate for moving image photography in which a plurality of fourth pixels each having a fourth switching element for reading out the electric charge when they are generated are provided in a matrix, and the first substrate. When still image shooting is performed, detection means for detecting the irradiation state of radiation based on the charges read from the second substrate, and still image shooting by the radiation detector based on the detection result by the detection means. Control means for controlling to perform.

According to the radiographic imaging device according to the first aspect, still image shooting is performed using the first substrate for still image shooting laminated on the radiation sensitive layer, while the first substrate of the radiation sensitive layer is Moving image shooting is performed using the second substrate for moving image shooting stacked on the opposite surface.

Here, in the present invention, when taking a still image using the first substrate, the detection unit detects the irradiation state of the radiation based on the electric charge read from the second substrate, and the control unit Based on the detection result by the detection means, the radiation detector is controlled to perform still image shooting.

Thus, according to the radiographic imaging device of the first aspect, when still image shooting is performed using the first substrate, based on the electric charges read from the second substrate provided for moving image shooting. Since the irradiation state of the radiation is detected, the irradiation state of the radiation can be detected with higher accuracy than when the detection is performed using the first substrate.

In the present invention, as the second aspect, the second substrate may have at least one of a low resolution and a small size as compared with the first substrate. Thereby, the irradiation state of radiation can be detected at higher speed.

In the present invention, as a third aspect, the second substrate may be configured such that pixels for detecting the radiation irradiation state are provided between pixels for capturing a radiation image. .

According to a fourth aspect of the present invention, there is provided, as a fourth aspect, first signal processing means for performing predetermined signal processing on the electric charges read from the first substrate in a state where power is supplied, and a state where power is supplied And second signal processing means for performing predetermined signal processing on the charges read from the second substrate, and the control means detects the start of radiation irradiation by the detection means. In this case, the power supply to the first substrate may be stopped. Thereby, power consumption can be reduced.

As a fifth aspect of the present invention, a binning state in which charges read from the second substrate are combined in units of adjacent pixels and a non-binning state in which the combining is not performed can be selectively set. The binning setting unit may be further provided, and the control unit may control the binning setting unit to set the binning state when the detection unit detects the start of radiation irradiation. Thereby, the irradiation state of radiation can be detected at higher speed.

According to a sixth aspect of the present invention, as a sixth aspect, when the control means detects the radiation irradiation state by the detection means, the charge readout speed from the second substrate is increased as compared with the case of moving image shooting. You may control to make it. Thereby, the irradiation state of radiation can be detected at higher speed.

In addition, the present invention provides, as a seventh aspect, a surface between the first substrate and the second substrate, a surface opposite to the surface on which the radiation sensitive layer of the first substrate is laminated, or the The second substrate is laminated on a surface opposite to the surface on which the radiation-sensitive layer is laminated, and generates light corresponding to the irradiated radiation or generates charges corresponding to the irradiated radiation. Two radiation sensitive layers may be further provided. Thereby, the radiation dose can also be detected.

In particular, in the seventh aspect, as the eighth aspect, the second substrate includes, as the second photoelectric conversion unit, a high-sensitivity photoelectric conversion unit and a low-sensitivity photoelectric conversion unit, each having different light detection sensitivities, When the detection means performs still image shooting using the first substrate, it detects the start of irradiation of the radiation based on the charge obtained by the high-sensitivity photoelectric conversion unit, and is obtained by the low-sensitivity photoelectric conversion unit. The irradiation stoppage of the radiation may be detected based on the generated electric charge. Thereby, the irradiation state of radiation can be detected with higher accuracy.

Further, according to the ninth aspect of the present invention, as the ninth aspect, when the radiation detector is used to capture a still image, the first substrate may be disposed on the radiation incident side of the radiation sensitive layer. Good. As a result, still images can be taken with higher image quality.

Furthermore, in the present invention, as a tenth aspect, when the radiation sensitive layer generates light corresponding to the irradiated radiation, the radiation sensitive layer may include a columnar crystal. As a result, still images can be taken with higher image quality.

On the other hand, in order to achieve the above object, the program according to the eleventh aspect of the present invention causes the computer to generate light corresponding to the irradiated radiation or generate a charge corresponding to the irradiated radiation. A radiation sensitive layer, laminated on the radiation sensitive layer, and when the radiation sensitive layer generates light, the first photoelectric conversion unit that generates a charge corresponding to the light and the charge generated by the first photoelectric conversion unit A plurality of first pixels having first switching elements for reading are provided in a matrix, or a plurality of second pixels having second switching elements for reading the charges when the radiation sensitive layer generates charges. A first substrate for photographing a still image in which second pixels are provided in a matrix, and a layer opposite to the first substrate of the radiation sensitive layer are stacked, and the radiation sensitive layer is A plurality of third pixels each having a second photoelectric conversion unit that generates a charge corresponding to the light and a third switching element for reading out the charge generated by the second photoelectric conversion unit. Or a second substrate for taking a moving image in which a plurality of fourth pixels provided with a fourth switching element for reading out the charge when the radiation sensitive layer generates a charge is provided in a matrix. When performing still image shooting using the first substrate by the radiation detector having, a detection means for detecting a radiation irradiation state based on the charge read from the second substrate, and a detection result by the detection means And a control means for controlling to take a still image by the radiation detector.

Therefore, according to the eleventh aspect, since the computer can be operated in the same manner as the radiographic imaging apparatus according to the first aspect, the radiation irradiation state can be detected with high accuracy as in the radiographic imaging apparatus. can do.

Furthermore, in order to achieve the above object, the radiographic imaging method according to the twelfth aspect generates a light corresponding to the irradiated radiation or generates a charge corresponding to the irradiated radiation. The first photoelectric conversion unit that is stacked on the radiation sensitive layer and generates a charge corresponding to the light when the radiation sensitive layer generates light, and for reading the charge generated by the first photoelectric conversion unit A plurality of first pixels provided with a first switching element are provided in a matrix or a plurality of second pixels provided with a second switching element for reading out the charge when the radiation sensitive layer generates a charge. Are stacked on a surface of the radiation sensitive layer opposite to the first substrate, and the radiation sensitive layer generates light. A plurality of third pixels having a second photoelectric conversion unit that generates a charge corresponding to the light and a third switching element for reading out the charge generated by the second photoelectric conversion unit in a matrix form Or a radiation detector having a second substrate for moving image photography in which a plurality of fourth pixels provided with a fourth switching element for reading out the charge when the radiation sensitive layer generates the charge are provided in a matrix. Thus, when performing still image shooting using the first substrate, based on the detection step of detecting the irradiation state of the radiation based on the charge read from the second substrate, and the detection result of the detection step, And a control step of controlling to take a still image by the radiation detector.

Therefore, according to the twelfth aspect, since it operates in the same manner as the radiographic image capturing apparatus according to the first aspect, it is possible to detect the radiation irradiation state with high accuracy as in the radiographic image capturing apparatus.

According to the present invention, when still image shooting is performed using the first substrate, the radiation irradiation state is detected based on the electric charge read from the second substrate provided for moving image shooting. Compared with the case where detection is performed using the first substrate, an effect that the irradiation state of radiation can be detected with high accuracy can be achieved.

It is a cross-sectional schematic diagram which shows schematic structure of the 3 pixel part of the radiation detector which concerns on embodiment. It is the schematic which shows typically an example of the crystal structure of the scintillator which concerns on embodiment. It is sectional drawing which showed roughly the structure of the signal output part of 1 pixel part of the radiation detector which concerns on embodiment. It is a schematic side view which shows the structure of the radiation detector which concerns on 1st Embodiment. It is a top view which shows the structure of the TFT substrate which concerns on 1st 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 block diagram which shows the principal part structure of the electric system of the electronic cassette concerning embodiment. It is a circuit diagram which shows the structure of the signal processing part 54B which concerns on embodiment. It is a circuit diagram which shows the structure of signal processing part 54A which concerns on embodiment. It is a flowchart which shows the flow of a process of the still image shooting processing program which concerns on embodiment. It is a top view which shows the structure of the TFT substrate which concerns on 2nd Embodiment. It is a schematic side view which shows the structure of the radiation detector which concerns on other embodiment. It is a top view which shows the structure of the TFT substrate which concerns on other embodiment. It is a top view which shows the structure of the TFT substrate which concerns on other embodiment. It is a graph with which it uses for description of the effect in the case of having a high sensitivity radiation detection pixel and a low sensitivity radiation detection pixel. It is a graph with which it uses for description of the switching between still image shooting and video shooting concerning other embodiments. It is the top view and side view which show the structure of the TFT substrate which concerns on other embodiment. It is a graph which shows an example of the sensitivity characteristic of various materials. It is a graph which shows an example of the sensitivity characteristic of various materials.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
First, the configuration of the indirect conversion radiation detector 20 according to the present embodiment will be described.

FIG. 1 is a schematic cross-sectional view schematically showing a configuration of three pixel portions of a radiation detector 20 according to an embodiment of the present invention.

The radiation detector 20 includes a TFT substrate 30A configured by sequentially forming a signal output unit 14, a sensor unit 13, and a transparent insulating film 7 on an insulating substrate 1, a scintillator 8, and an adhesive layer 22. And a TFT substrate 30B having substantially the same configuration as the TFT substrate 30A are stacked in this order, and the pixel portion is configured by the TFT substrate 30A, the signal output unit 14 of the TFT substrate 30B, and the sensor unit 13. . A plurality of pixel units are arranged on the substrate 1, and the signal output unit 14 and the sensor unit 13 in each pixel unit are configured to overlap each other.

The scintillator 8 is formed of a columnar crystal on the sensor unit 13 via the transparent insulating film 7, and forms a phosphor that emits light by converting radiation incident from above (TFT substrate 30 B side) into light. It is a thing. Providing such a scintillator 8 absorbs the radiation transmitted through the subject and the TFT substrate 30B and emits light.

The wavelength range of light emitted by the scintillator 8 is preferably the visible light range (wavelength 360 nm to 830 nm), and in order to enable monochrome imaging by the radiation detector 20, the wavelength range of green is included. Is more preferable.

Specifically, the phosphor used in the scintillator 8 preferably contains cesium iodide (CsI) when imaging using X-rays as radiation, and the emission spectrum upon X-ray irradiation is, for example, 420 nm to It is particularly preferred to use CsI: Tl at 700 nm. Note that the emission peak wavelength in the visible light region of CsI: Tl is 565 nm.

In the present embodiment, as shown in FIG. 2 as an example, the scintillator 8 is formed with a columnar portion made of a columnar crystal 71A on the radiation incident side (TFT substrate 30B side). A non-columnar portion made of a non-columnar crystal 71B is formed on the opposite side. A material containing CsI is used as the scintillator 8, and the material is directly deposited on the TFT substrate 30A, so that the columnar portion and the non-columnar portion are formed. The formed scintillator 8 is obtained. In the scintillator 8 according to the present embodiment, the average diameter of the columnar crystals 71A is approximately uniform along the longitudinal direction of the columnar crystals 71A.

As described above, by forming the scintillator 8 with the columnar portion, the light generated by the scintillator 8 travels in the columnar crystal 71A and is emitted to the TFT substrate 30A via the non-columnar crystal 71B. By suppressing the diffusion of the light emitted to the TFT substrate 30A side, a reduction in the sharpness of the resultant radiographic image is suppressed. Further, the light that has traveled toward the tip of the columnar crystal 71A of the scintillator 8 is emitted to the TFT substrate 30B, and contributes to an increase in the amount of light received by the TFT substrate 30B.

Note that it is preferable that the non-columnar portion has a porosity close to 0 (zero), whereby reflection of light by the non-columnar portion can be suppressed. Further, it is preferable to make the non-columnar portion as thin as possible (about 10 μm).

In the present embodiment, the TFT substrate 30B is disposed on the radiation irradiation surface side of the scintillator 8, but the method of disposing the scintillator 8 and the TFT substrate 30B in such a positional relationship is “surface reading method (ISS). : Irradiation Side Sampling) ”. Since the scintillator emits light more strongly on the radiation incident side, the surface reading method (ISS) in which the TFT substrate is disposed on the radiation incident side of the scintillator is the “back surface reading method (in which the TFT substrate is disposed on the opposite side of the scintillator from the radiation incident side” Since the TFT substrate and the light emission position of the scintillator are closer to each other than PSS (Penetration Side Sampling), the resolution of the radiographic image obtained by imaging is high, and the amount of light received by the TFT substrate is increased, resulting in radiation. Image sensitivity is improved.

On the other hand, 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 charges are generated. It is comprised with the organic photoelectric conversion material to generate | occur | produce.

The upper electrode 6 is preferably made of a conductive material transparent to at least the emission wavelength of the scintillator because it is necessary to make the light generated by the scintillator enter the photoelectric conversion film 4. It is preferable to use a transparent conductive oxide (TCO) having a high transmittance with respect to the surface and a low resistance value. Although a metal thin film such as Au can be used as the upper electrode 6, TCO is preferable because it tends to increase the resistance value when it is desired to obtain a transmittance of 90% or more. For example, ITO, IZO, AZO, FTO, SnO ₂ , TiO ₂ , ZnO _{2 and the} like can be preferably used, and ITO is most preferable from the viewpoint of process simplicity, low resistance, and transparency. Note that the upper electrode 6 may have a single configuration common to all the pixel portions, or may be divided for each pixel portion.

The photoelectric conversion film 4 includes an organic photoelectric conversion material, absorbs light emitted from the scintillator 8, and generates electric charges according to the absorbed light. In this way, the photoelectric conversion film 4 containing an organic photoelectric conversion material 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. The noise generated by the radiation such as being absorbed by the photoelectric conversion film 4 can be effectively suppressed.

The organic photoelectric conversion material constituting the photoelectric conversion film 4 is preferably such that its absorption peak wavelength is closer to the emission peak wavelength of the scintillator in order to absorb light emitted by the scintillator 8 most efficiently. Ideally, the absorption peak wavelength of the organic photoelectric conversion material matches the emission peak wavelength of the scintillator, but if the difference between the two is small, the light emitted from the scintillator can be sufficiently absorbed. Specifically, the difference between the absorption peak wavelength of the organic photoelectric conversion material and the emission peak wavelength with respect to the radiation of the scintillator is preferably within 10 nm, and more preferably within 5 nm.

Examples of the organic photoelectric conversion material that can satisfy such conditions 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: Tl is used as the material of the scintillator 8, the difference in peak wavelength can be made within 10 nm. The amount of charge generated in the photoelectric conversion film 4 can be substantially maximized.

Next, the photoelectric conversion film 4 applicable to the radiation detector 20 according to the present embodiment will be specifically described.

The electromagnetic wave absorption / photoelectric conversion site in the radiation detector 20 according to the present embodiment is constituted by an organic layer including a pair of electrodes 2 and 6 and an organic photoelectric conversion film 4 sandwiched between the electrodes 2 and 6. be able to. More specifically, this organic layer is a part that absorbs electromagnetic waves, a photoelectric conversion part, an electron transport part, a hole transport part, an electron blocking part, a hole blocking part, a crystallization preventing part, an electrode, and an interlayer contact improvement. It can be formed by stacking or mixing parts.

The organic layer preferably contains an organic p-type compound or an organic n-type compound.

An organic p-type semiconductor (compound) is a donor organic semiconductor (compound) typified by a hole-transporting organic compound and refers to an organic compound having a property of easily donating electrons. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Therefore, any organic compound can be used as the donor organic compound as long as it is an electron-donating organic compound.

An organic n-type semiconductor (compound) is an acceptor organic semiconductor (compound) typified by an electron-transporting organic compound and refers to an organic compound having a property of easily accepting electrons. More specifically, the organic compound having the higher electron affinity when two organic compounds are used in contact with each other. Therefore, as the acceptor organic compound, any organic compound can be used as long as it is an electron-accepting organic compound.

The materials applicable as the organic p-type semiconductor and the organic n-type semiconductor, and the configuration of the photoelectric conversion film 4 are described in detail in Japanese Patent Application Laid-Open No. 2009-32854, and thus the description thereof is omitted.

The thickness of the photoelectric conversion film 4 is preferably as large as possible in terms of absorbing light from the scintillator 8. However, when the thickness is more than a certain level, the photoelectric conversion film 4 is generated in the photoelectric conversion film 4 by a bias voltage applied from both ends of the photoelectric conversion film 4. Since electric field strength is reduced and charges cannot be collected, the thickness is preferably 30 nm to 300 nm, more preferably 50 nm to 250 nm, and particularly preferably 80 nm to 200 nm.

In the radiation detector 20 shown in FIG. 1, the photoelectric conversion film 4 has a single-sheet configuration common to all the pixel portions, but may be divided for each pixel portion.

The lower electrode 2 is a thin film divided for each pixel portion. The lower electrode 2 can be made of a transparent or opaque conductive material, and aluminum, silver, or the like can be suitably used.

The thickness of the lower electrode 2 can be, for example, 30 nm or more and 300 nm or less.

In the sensor unit 13, by applying a predetermined bias voltage between the upper electrode 6 and the lower electrode 2, one of electric charges (holes, electrons) generated in the photoelectric conversion film 4 is moved to the upper electrode 6. The other can be moved to the lower electrode 2. In the radiation detector 20 of the present embodiment, a wiring is connected to the upper electrode 6, and a bias voltage is applied to the upper electrode 6 through this wiring. In addition, the polarity of the bias voltage is determined so that electrons generated in the photoelectric conversion film 4 move to the upper electrode 6 and holes move to the lower electrode 2, but this polarity is reversed. May be.

The sensor unit 13 constituting each pixel unit only needs to include at least the lower electrode 2, the photoelectric conversion film 4, and the upper electrode 6. In order to suppress an increase in dark current, the electron blocking film 3 and hole blocking are performed. It is preferable to provide at least one of the films 5, and it is more preferable to provide both.

The electron blocking film 3 can be provided between the lower electrode 2 and the photoelectric conversion film 4. When a bias voltage is applied between the lower electrode 2 and the upper electrode 6, electrons are transferred from the lower electrode 2 to the photoelectric conversion film 4. It is possible to suppress the dark current from increasing due to the injection of.

An electron donating organic material can be used for the electron blocking film 3.

The material actually used for the electron blocking film 3 may be selected according to the material of the adjacent electrode, the material of the adjacent photoelectric conversion film 4 and the like, and 1.3 eV or more from the work function (Wf) of the material of the adjacent electrode. Those having a large electron affinity (Ea) and an Ip equivalent to or smaller than the ionization potential (Ip) of the material of the adjacent photoelectric conversion film 4 are preferable. Since the material applicable as the electron donating organic material is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted. The photoelectric conversion film 4 may be formed by further containing fullerenes or carbon nanotubes.

The thickness of the electron blocking film 3 is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, and particularly preferably, in order to surely exhibit the dark current suppressing effect and prevent a decrease in photoelectric conversion efficiency of the sensor unit 13. It is 50 nm or more and 100 nm or less.

The hole blocking film 5 can be provided between the photoelectric conversion film 4 and the upper electrode 6. When a bias voltage is applied between the lower electrode 2 and the upper electrode 6, the hole blocking film 5 is transferred from the upper electrode 6 to the photoelectric conversion film 4. It is possible to suppress the increase in dark current due to the injection of holes.

An electron-accepting organic material can be used for the hole blocking film 5.

The thickness of the hole blocking film 5 is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, and particularly preferably, in order to surely exhibit the dark current suppressing effect and prevent a decrease in photoelectric conversion efficiency of the sensor unit 13. Is from 50 nm to 100 nm.

The material actually used for the hole blocking film 5 may be selected according to the material of the adjacent electrode, the material of the adjacent photoelectric conversion film 4 and the like, and 1.3 eV from the work function (Wf) of the material of the adjacent electrode. As described above, it is preferable that the ionization potential (Ip) is large and that the Ea is equal to or larger than the electron affinity (Ea) of the material of the adjacent photoelectric conversion film 4. Since the material applicable as the electron-accepting organic material is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

In addition, when a bias voltage is set so that holes move to the upper electrode 6 and electrons move to the lower electrode 2 among the charges generated in the photoelectric conversion film 4, the electron blocking film 3 and the hole blocking are set. The position of the film 5 may be reversed. Moreover, it is not necessary to provide both the electron blocking film 3 and the hole blocking film 5. If either one is provided, a certain degree of dark current suppressing effect can be obtained.

A signal output unit 14 is formed on the surface of the substrate 1 below the lower electrode 2 of each pixel unit.

FIG. 3 schematically shows the configuration of the signal output unit 14.

Corresponding to the lower electrode 2, a capacitor 9 that accumulates the charges transferred to the lower electrode 2, and a field effect thin film transistor (Thin Transistor, hereinafter simply referred to as an electric signal converted from the electric charge accumulated in the capacitor 9) "Thin film transistor") 10 is formed. 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 a plan view. With such a configuration, the signal output unit 14 and the sensor unit 13 in each pixel unit are connected to each other. There will be 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 via a wiring made of a conductive material penetrating an insulating film 11 provided between the 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. .

The active layer 17 can be formed of, for example, amorphous silicon, amorphous oxide, organic semiconductor material, carbon nanotube, or the like. In addition, the material which comprises the active layer 17 is not limited to these.

The amorphous oxide that can form 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 2 of In, Ga, and Zn. (Eg, In—Zn—O, In—Ga—O, and Ga—Zn—O) are more preferable, and oxides including In, Ga, and Zn are 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 of less than 6) is preferable, and InGaZnO is particularly preferable. ₄ is more preferable. In addition, the amorphous oxide which can comprise the active layer 17 is not limited to these.

Examples of the organic semiconductor material that can form the active layer 17 include, but are not limited to, phthalocyanine compounds, pentacene, vanadyl phthalocyanine, and the like. Note that the configuration of the phthalocyanine compound is described in detail in JP-A-2009-212389, and thus the description thereof is omitted.

If the active layer 17 of the thin film transistor 10 is formed of an amorphous oxide, an organic semiconductor material, or a carbon nanotube, it will not absorb radiation such as X-rays, or even if it absorbs it, it will remain in a very small amount. Generation of noise in the portion 14 can be effectively suppressed.

Further, when the active layer 17 is formed of carbon nanotubes, the switching speed of the thin film transistor 10 can be increased, and the thin film transistor 10 having a low degree of light absorption in the visible light region can be formed. Note that when the active layer 17 is formed of carbon nanotubes, the performance of the thin film transistor 10 is remarkably deteriorated only by mixing a very small amount of metallic impurities into the active layer 17. It is necessary to form by separating and extracting.

Here, any of the above-described amorphous oxide, organic semiconductor material, carbon nanotube, and organic photoelectric conversion material can be formed at a low temperature. Therefore, the 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, and polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, and poly (chlorotrifluoroethylene). 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.

In addition, the substrate 1 is provided with 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, and the like. May be.

Since aramid can be applied to a high temperature process of 200 degrees or more, the transparent electrode material can be cured at a high temperature to reduce the resistance, and it 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 substrate 1 may be formed by laminating an ultrathin glass substrate and aramid.

Bionanofiber is a composite of cellulose microfibril bundle (bacterial cellulose) produced by bacteria (acetic acid bacteria, Acetobacter® Xylinum) and 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 acrylic resin or epoxy resin into 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. The substrate 1 can be formed thinly.

The configuration of the TFT substrate 30B according to the present embodiment is substantially the same as that of the TFT substrate 30A, but the TFT substrate 30A is slightly smaller in size than the scintillator 8 as schematically shown in FIG. The TFT substrate 30B is different from the TFT substrate 30A in that the TFT substrate 30B has substantially the same size as the scintillator 8, and the TFT substrate 30B is configured to have a higher pixel density (higher resolution) than the TFT substrate 30A. ing. In addition, it is not restricted to this form, You may be considered as the difference only in any one of these two points.

As described above, in the radiation detector 20 according to the present embodiment, the scintillator 8 is formed directly on the TFT substrate 30A by vapor deposition, while the side of the scintillator 8 opposite to the surface on which the TFT substrate 30A is provided. The TFT substrate 30B is bonded to the surface of the TFT substrate 30 via the adhesive layer 22. However, the present invention is not limited to this. For example, the scintillator 8 is formed directly on the TFT substrate 30B by vapor deposition. It goes without saying that the TFT substrate 30A may be formed by other methods such as a method of bonding the TFT substrate 30A to the surface opposite to the surface on which the substrate 30B is provided via the adhesive layer 22.

Also, in the radiation detector 20 according to the present embodiment, it is preferable to control the tip of each columnar part of the scintillator 8 to be as flat as possible. Specifically, it can be realized by controlling the temperature of the evaporation target substrate at the end of evaporation. For example, if the temperature of the substrate to be deposited at the end of vapor deposition is 110 ° C., the tip angle is about 170 degrees, and if the temperature of the substrate to be deposited at the end of vapor deposition is 140 degrees Celsius, the tip angle is about 60 degrees. If the temperature of the vapor deposition substrate at that time is 200 ° C., the tip angle is approximately 70 degrees, and if the temperature of the vapor deposition substrate at the end of vapor deposition is 260 ° C., the tip angle is approximately 120 degrees. Since this control is described in detail in Japanese Patent Application Laid-Open No. 2010-25620, further description is omitted.

On the other hand, on the TFT substrate 30A and the TFT substrate 30B, as shown in FIG. 5, the pixels 32 including the sensor unit 13, the capacitor 9, and the thin film transistor 10 are arranged in a certain direction (row direction in FIG. 5) and A plurality of two-dimensional shapes are provided in a crossing direction (column direction in FIG. 5) with respect to a certain direction.

In addition, the radiation detector 20 extends in the predetermined direction (scanning line direction), and extends in the intersecting direction (signal wiring direction) with a plurality of gate wirings 34 for turning on and off each thin film transistor 10. A plurality of data wirings 36 for reading out charges through the thin film transistor 10 in the on state are provided in two sets corresponding to the TFT substrate 30A and the TFT substrate 30B, respectively.

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.

Next, the configuration of a portable radiation image capturing apparatus (hereinafter referred to as “electronic cassette”) 40 that incorporates the radiation detector 20 and captures a radiation image will be described. FIG. 6 is a perspective view showing the configuration of the electronic cassette 40 according to the present exemplary embodiment.

As shown in the figure, the electronic cassette 40 includes a flat housing 41 made of a material that transmits radiation, and has a waterproof and airtight structure. Inside the housing 41 are a radiation detector 20 that detects the radiation X that has passed through the subject from the irradiation surface side of the housing 41 that is irradiated with the radiation X, and a lead plate 43 that absorbs backscattered rays of the radiation X. Are arranged in order. The case 41 has a quadrilateral imaging region 41A capable of detecting radiation in a region corresponding to the arrangement position of the radiation detector 20 on one flat surface. As shown in FIG. 7, the radiation detector 20 is disposed so that the TFT substrate 30B is on the imaging region 41A side, and is affixed to the inside of the housing 41 constituting the imaging region 41A.

In addition, a case 42 that accommodates a cassette control unit 58 and a power supply unit 70 described later is disposed on one end side inside the housing 41 at a position that does not overlap the radiation detector 20 (outside the range of the imaging region 41A). Yes.

FIG. 8 is a block diagram showing the main configuration of the electrical system of the electronic cassette 40 according to the present embodiment.

In the TFT substrates 30A and 30B, a gate line driver 52 is disposed on one side of two adjacent sides, and a signal processing unit 54 is disposed on the other side. Hereinafter, when the gate line driver 52 and the signal processing unit 54 provided corresponding to the two TFT substrates 30A and 30B are distinguished from each other, the gate line driver 52 and the signal processing unit 54 corresponding to the TFT substrate 30A are denoted by A. The gate line driver 52 and the signal processing unit 54 corresponding to the TFT substrate 30B will be described with reference character B.

Each gate wiring 34 of the TFT substrate 30A is connected to the gate line driver 52A, each data wiring 36 of the TFT substrate 30A is connected to the signal processing unit 54A, and each gate wiring 34 of the TFT substrate 30B is a gate line. Connected to the driver 52B, each data wiring 36 of the TFT substrate 30B is connected to the signal processing unit 54B.

In addition, the housing 41 includes an image memory 56, a cassette control unit 58, and a wireless communication unit 60.

The thin film transistors 10 on the TFT substrates 30A and 30B are sequentially turned on in units of scanning lines by signals supplied from the gate line drivers 52A and 52B via the gate wiring 34, and the electric charges read by the thin film transistors 10 turned on. Is transmitted through the data wiring 36 as an electrical signal and input to the signal processing units 54A and 54B. As a result, the charges are sequentially read in units of scanning lines, and a two-dimensional radiation image can be acquired.

Here, the configuration of the signal processing unit 54A and the signal processing unit 54B according to the present embodiment will be described. FIG. 9 is a circuit diagram showing the configuration of the signal processing unit 54B according to the present embodiment.

As shown in the figure, the signal processing unit 54B according to the present embodiment includes a variable gain preamplifier (charge amplifier) 82 and a sample hold circuit 86 corresponding to each of the data wirings 36 on the TFT substrate 30B. Is provided.

The variable gain preamplifier 82 includes an operational amplifier 82A whose positive input side is grounded, a capacitor 82B connected in parallel between the negative input side and the output side of the operational amplifier 82A, and a reset switch 82C. The reset switch 82C is switched by the cassette control unit 58.

Further, the signal processing unit 54B according to the present embodiment includes a multiplexer 88 and an A / D (analog / digital) converter 89. Note that the sample control of the sample hold circuit 86 and the selection output by the switch 88A provided in the multiplexer 88 are also switched by the cassette control unit 58.

When detecting the radiation image, the cassette control unit 58 first discharges the charge accumulated in the capacitor 82B by turning on the reset switch 82C of the variable gain preamplifier 82 for a predetermined period.

On the other hand, the electric charge accumulated in each capacitor 9 of each pixel 32 of the TFT substrate 30B by being irradiated with the radiation X is connected as an electric signal when the connected thin film transistor 10 is turned on. The electric signal transmitted through the data line 36 and transmitted through the data line 36 is amplified by a corresponding variable gain preamplifier 82 at a predetermined amplification factor.

On the other hand, the cassette control unit 58 causes the sample hold circuit 86 to hold the signal level of the electric signal amplified by the variable gain preamplifier 82 by driving the sample hold circuit 86 for a predetermined period after performing the above-described discharge.

The signal levels held in each sample and hold circuit 86 are sequentially selected by the multiplexer 88 in accordance with control by the cassette control unit 58 and are A / D converted by the A / D converter 89 and photographed. Image data indicating a radiation image is generated.

On the other hand, an image memory 56 is connected to the signal processing unit 54B, and the image data output from the A / D converter 89 of the signal processing unit 54B is stored in the image memory 56 in order. 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.

On the other hand, FIG. 10 shows a circuit diagram showing a configuration of the signal processing unit 54A according to the present embodiment.

As shown in the figure, the signal processing unit 54A according to the present embodiment corresponds to each of the data wirings 36 on the TFT substrate 30A, and includes a variable gain preamplifier (charge amplifier) 92, a binning unit 94, and a sample hold. Circuit 96 is provided.

The variable gain preamplifier 92 includes an operational amplifier 92A whose positive input side is grounded, a capacitor 92B connected in parallel between the negative input side and the output side of the operational amplifier 92A, and a reset switch 92C. The reset switch 92C is switched by the cassette control unit 58.

The binning unit 94 includes a switch 94A connected between adjacent communication lines and switches 94B and 94C connected in the middle of the communication lines, and each of the switches 94A, 94B and 94C is also cassette-controlled. Switching is performed by the unit 58. In the present embodiment, the switch 94A and the switch 94B are turned on and the switch 94C is turned off to be in the binning connection state. The switch 94B and the switch 94C are turned on and the switch 94A is turned off. By doing so, a normal connection state is established.

The signal processing unit 54A according to the present embodiment includes a multiplexer 98 and an A / D converter 99. Note that the sample control of the sample hold circuit 96 and the selection output by the switch 98A provided in the multiplexer 98 are also switched by the cassette control unit 58.

Each of the data wirings 36 of the TFT substrate 30A is individually connected to the input terminal of the multiplexer 98 through the variable gain preamplifier 92, the binning unit 94, and the sample hold circuit 96 in order. The output terminal of the multiplexer 98 is connected to the input terminal of the A / D converter 99 whose output terminal is connected to the image memory 56.

When detecting the radiation image, the cassette control unit 58 first discharges (resets) the charge accumulated in the capacitor 92B by turning on the reset switch 92C of the variable gain preamplifier 92 for a predetermined period.

Next, the cassette control unit 58 turns off the reset switch 92C of the variable gain preamplifier 92 and sets the binning connection state or the normal connection state by setting the on / off states of the switches 94A to 94C of the binning unit 94. .

On the other hand, the charge accumulated in each capacitor 9 of the pixel 32 of the TFT substrate 30A by the irradiation with the radiation X is the data connected as an electrical signal when the connected thin film transistor 10 is turned on. The electrical signal transmitted through the wiring 36 and transmitted through the data wiring 36 is amplified by a corresponding variable gain preamplifier 92 at a predetermined amplification factor, and then synthesized by the binning unit 94 as necessary.

On the other hand, after the discharge of the capacitor 92B and the setting of the binning unit 94 are performed, the cassette control unit 58 is amplified by the variable gain preamplifier 92 by driving the sample hold circuit 96 for a predetermined period, and binning is performed as necessary. The signal level of the (synthesized) electric signal is held in the sample hold circuit 96.

The signal levels held in the sample and hold circuits 96 are sequentially selected by the multiplexer 98 in accordance with the control by the cassette control unit 58 and are A / D converted by the A / D converter 99 to be photographed. Image data indicating a radiation image is generated.

On the other hand, an image memory 56 is connected to the signal processing unit 54A, and the image data output from the A / D converter 99 of the signal processing unit 54A is stored in the image memory 56 in order. 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 is constituted by a microcomputer, and includes a CPU (Central Processing Unit) 58A, a memory 58B including a ROM (Read Only Memory) and a RAM (Random Access Memory), a non-volatile storage unit 58C including a flash memory and the like. The operation of the entire electronic cassette 40 is controlled.

Also, a wireless communication unit 60 is connected to the cassette control unit 58. The wireless communication unit 60 corresponds to a wireless LAN (Local Area Network) standard represented by IEEE (Institute of Electrical and Electronics Electronics) (802.11a / b / g / n), etc., and communicates with an external device by wireless communication. Control the transmission of various information between them. 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, and the various circuits and elements described above ( gate line drivers 52A and 52B, signal processing units 54A and 54B, image memory 56, wireless communication unit 60, and cassette control). The microcomputer functioning as the unit 58 is operated by the electric 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. 8, wiring for connecting the power supply unit 70 to various circuits and elements is omitted.

Note that in the electronic cassette 40 according to the present exemplary embodiment, the cassette control unit 58 performs power supply and power supply stop from the power supply unit 70 to the signal processing unit 54A and power supply and power supply stop from the power supply unit 70 to the signal processing unit 54B. Can be switched individually.

By the way, the electronic cassette 40 according to the present embodiment is configured to be able to perform both still image shooting and moving image shooting. Here, in the electronic cassette 40 according to the present exemplary embodiment, the TFT substrate 30A is used as a moving image shooting substrate, and the TFT substrate 30B is used as a still image shooting substrate.

When radiographic images are captured, the electronic cassette 40 according to the present embodiment is arranged with the imaging region 41A facing upward and spaced apart from the radiation generator 80 that generates radiation, as shown in FIG. The imaging target region B of the patient is arranged on the imaging area. The radiation generator 80 emits radiation X having a radiation dose according to imaging conditions given in advance. The radiation X emitted from the radiation generator 80 is irradiated to the electronic cassette 40 after carrying image information by passing through the imaging target region B.

The radiation X emitted from the radiation generator 80 reaches the electronic cassette 40 after passing through the imaging target region B. As a result, charges corresponding to the dose of the irradiated radiation X are generated in each sensor unit 13 of the radiation detector 20 incorporated in the electronic cassette 40, and the charges generated by the sensor unit 13 are accumulated in the capacitor 9. The

On the other hand, the cassette control unit 58 controls the gate line driver 52B when shooting a still image, and sequentially outputs an ON signal line by line from the gate line driver 52B to each gate wiring 34 of the TFT substrate 30B. Read image information. Accordingly, the image information read from the TFT substrate 30B of the radiation detector 20 is stored in the image memory 56 as image data (hereinafter referred to as “still image data”) after passing through the signal processing unit 54B. The cassette control unit 58 reads the still image data from the image memory 56 and transmits it to the console via the wireless communication unit 60. The console stores the received still image data in a predetermined storage device and causes the display device to display a still image indicated by the image data.

On the other hand, the cassette control unit 58 controls the gate line driver 52A when shooting a moving image, and sequentially outputs an ON signal line by line from the gate line driver 52A to each gate wiring 34 of the TFT substrate 30A. Then, the reading of the image information is repeatedly executed at a speed corresponding to a predetermined frame rate (30 frames / second in the present embodiment). Thus, the image information read from the TFT substrate 30A of the radiation detector 20 is sequentially stored in the image memory 56 as image data (hereinafter referred to as “moving image data”) after passing through the signal processing unit 54A. The cassette control unit 58 continuously reads out the moving image data from the image memory 56 and transmits the moving image data to the console via the wireless communication unit 60 in real time. The console displays a moving image (perspective image) by displaying the moving image indicated by the moving image data received from the electronic cassette 40 in real time on the display device.

In the electronic cassette 40 according to the present embodiment, still image data read from the TFT substrate 30B and moving image data read from the TFT substrate 30A are stored in different storage areas of the image memory 56, respectively. It is supposed to be.

By the way, in the electronic cassette 40 according to the present exemplary embodiment, when a still image is captured, the start of radiation irradiation is detected based on information read from the TFT substrate 30A, and the start of the irradiation is detected. It is equipped with a synchronization-free function that captures radiographic images.

Next, with reference to FIG. 11, the operation of the electronic cassette 40 according to the present exemplary embodiment when the synchronization free function is activated will be described in detail. FIG. 11 is a flowchart showing a flow of processing of a still image shooting processing program executed by the CPU 58A in the cassette control unit 58 of the electronic cassette 40 at this time, and the program is stored in advance in the ROM of the memory 58B. Yes.

In step 100 of the figure, the cassette control unit 58 performs control so as to start power supply from the power supply unit 70 to the signal processing unit 54A, and in the next step 102, the binning unit 94 of the signal processing unit 54A is in the binning connection state. Control to be

In the next step 104, the cassette control unit 58 controls the gate line driver 52A to sequentially output an ON signal line by line from the gate line driver 52A to each gate wiring 34, and the capacitor in each pixel 32 of the TFT substrate 30A. 9, by resetting the pixels 32 of the TFT substrate 30A by discharging the charges accumulated in the TFT 9, the charge reading speed (frame rate) from the TFT substrate 30A is controlled to be higher than that for moving image shooting. To do. Note that the reset operation of each pixel 32 performed by the process of step 104 may be performed only once or may be repeated a plurality of times.

In the next step 105, the cassette control unit 58 starts the above-described operation during moving image shooting. Thereby, the moving image data is sequentially stored in the image memory 56.

Therefore, in the next step 106, the cassette control unit 58 reads out the moving image data stored in the image memory 56 from the signal processing unit 54A, and based on the moving image data, the radiation X-ray dose (hereinafter referred to as irradiation dose). In the next step 108, it is determined whether or not radiation irradiation has been started by determining whether or not the derived radiation dose has reached a predetermined threshold value. When a negative determination is made, the process returns to step 106, while when an affirmative determination is made, the process proceeds to step 109. In the present embodiment, the radiation dose is derived in step 106 by adding all the pixel values in the moving image data stored in the image memory 56 from the signal processing unit 54A. However, the present invention is not limited to this, and a form derived by adding a part of pixel values in the moving image data, a form derived by calculating an average value of at least a part of pixel values in the moving image data, etc. It is good.

In step 109, the cassette control unit 58 stops the operation at the time of moving image shooting started by the processing of step 105, and in the next step 110, the binning unit 94 of the signal processing unit 54A is set in the normal connection state. In the next step 112, control is performed so as to stop power supply from the power supply unit 70 to the signal processing unit 54A.

In the next step 114, the cassette control unit 58 performs control so that power supply from the power supply unit 70 to the signal processing unit 54B is started, and in the next step 116, the gate line driver 52B is controlled to control the gate line driver 52B. The gate signal 34 is sequentially output to the gate wiring 34 one line at a time to discharge the charge accumulated in the capacitor 9 in each pixel 32 on the TFT substrate 30B, thereby resetting each pixel 32 on the TFT substrate 30B. Note that the reset operation of each pixel 32 performed by the process of step 116 may be performed only once or may be repeated a plurality of times.

In the next step 118, the cassette control unit 58 executes the above-described operation at the time of still image shooting, and waits in the next step 120 until the operation is completed.

In the next step 122, the cassette control unit 58 reads out the still image data stored in the image memory 56, and in the next step 124, the processing of step 122 of the capacitor 9 in each pixel 32 of the radiation detector 20 is performed. After resetting each pixel 32 by discharging the residual charge or the charge in which the dark current is accumulated after the completion of the charge reading, the power supply from the power supply unit 70 started by the process of step 114 to the signal processing unit 54B. In step 126, the read still image data is transmitted to the console via the wireless communication unit 60, and then the still image shooting processing program is terminated.

Incidentally, in the radiation detector 20 according to the present embodiment, since the non-columnar portion is provided in the scintillator 8, the adhesion with the TFT substrate 30A can be increased. However, the non-columnar part is not essential, and the non-columnar part may not be provided.

Further, in the radiation detector 20 according to the present embodiment, the photoelectric conversion film 4 is made of an organic photoelectric conversion material, and radiation is hardly absorbed by the photoelectric conversion film 4. For this reason, in the radiation detector 20 according to the present embodiment, the radiation X passes through the TFT substrate 30B due to the ISS configuration, but the radiation X absorbed by the photoelectric conversion film 4 of the TFT substrate 30B is small. It is possible to suppress a decrease in sensitivity to In the ISS, the radiation X passes through the TFT substrate 30B and reaches the scintillator 8. In this way, when the photoelectric conversion film 4 of the TFT substrate 30B is made of an organic photoelectric conversion material, the radiation X in the photoelectric conversion film 4 is obtained. Therefore, it is suitable for ISS.

Further, 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. For this reason, the board | substrate 1 can be formed with a plastic resin, aramid, and bio-nanofiber with little radiation absorption. Since the substrate 1 formed in this way has a small amount of radiation absorption, a decrease in sensitivity to the radiation X can be suppressed even when the radiation X passes through the TFT substrate 30B by ISS.

Further, according to the present embodiment, as shown in FIG. 7, the radiation detector 20 is attached to the imaging region 41A portion in the housing 41 so that the TFT substrate 30B is on the imaging region 41A side. When the substrate 1 is formed of a highly rigid plastic resin, aramid, or bionanofiber, the radiation detector 20 itself has a high rigidity, so that the imaging region 41A portion of the housing 41 can be formed thin. In addition, when the substrate 1 is formed of a highly rigid plastic resin, aramid, or bionanofiber, the radiation detector 20 itself has flexibility, so that even when an impact is applied to the imaging region 41A, the radiation detector 20 is damaged. It ’s hard.

As described above in detail, in the present embodiment, when still image shooting is performed using the first substrate (TFT substrate 30B in the present embodiment), the second substrate provided for moving image shooting ( In the present embodiment, since the radiation irradiation state is detected based on the electric charges read from the TFT substrate 30A), the radiation irradiation state is increased compared to the case where detection is performed using the first substrate. It can be detected with accuracy.

In this embodiment, since the second substrate has a lower resolution and a smaller size than the first substrate, the radiation irradiation state can be detected at a higher speed.

In the present embodiment, the first signal processing means (in this embodiment, the signal processing unit) performs predetermined signal processing on the electric charges read from the first substrate in a state where power is supplied. 54B) and second signal processing means (in this embodiment, signal processing unit 54A) that performs predetermined signal processing on the electric charges read from the second substrate in a state where power is supplied. When the irradiation start of the radiation is detected, power supply to the first substrate is controlled to be stopped, so that power consumption can be reduced.

In the present embodiment, a binning setting unit configured to selectively set a binning state in which charges read from the second substrate are combined in units of adjacent pixels and a non-binning state in which the combining is not performed. (In this embodiment, a binning unit 94) is further provided, and when the radiation irradiation state is detected, the binning setting means is controlled to set the binning state, so that the radiation irradiation is performed at a higher speed. The state can be detected.

Further, in the present embodiment, when detecting the irradiation state of the radiation, the charge readout speed from the second substrate is controlled to be increased as compared with the case of moving image shooting, so that the radiation is faster. The irradiation state can be detected.

In the present embodiment, when the radiation detector is used to capture a still image, the first substrate is disposed on the radiation incident side of the radiation sensitive layer (scintillator 8 in the present embodiment). Therefore, still images can be taken with higher image quality.

Furthermore, in the present embodiment, the radiation sensitive layer is configured to include a columnar crystal (CsI in the present embodiment) that generates light according to the irradiated radiation. A still image can be taken.

[Second Embodiment]
In the first embodiment described above, an example has been described in which all image information read from the TFT substrate 30A is used for detection of radiation irradiation start when the synchronization-free function is activated. In the embodiment, an example in which some pixels 32 in the TFT substrate 30A are applied as pixels for detecting a radiation irradiation state will be described.

FIG. 12 shows the configuration of the TFT substrate 30A 'in the electronic cassette 40 according to the second embodiment.

As shown in the figure, on the TFT substrate 30A ′ に according to the present embodiment, the pixels 32 including the sensor unit 13, the capacitor 9, and the thin film transistor 10 described above are arranged in a certain direction (the row direction in FIG. A plurality of lines are provided in a two-dimensional manner in the scanning line direction) and the crossing direction with respect to the certain direction (column direction in FIG.

The radiation detector 20 according to the present embodiment includes a plurality of gate lines 34 extending in the predetermined direction (scanning line direction) for turning on / off each thin film transistor 10 and the crossing direction ( A plurality of data wirings 36 are provided extending in the signal wiring direction and for reading out charges through the thin film transistor 10 in the on state. The radiation detector 20 has a flat plate shape and a quadrilateral shape having four sides on the outer edge in a plan view, more specifically, a rectangular shape.

Here, in the radiation detector 20 according to the present embodiment, a part of the pixels 32 is used to detect the irradiation state of the radiation, and a moving image of the radiation image is captured by the remaining pixels 32. Hereinafter, the pixels 32 for detecting the radiation irradiation state are referred to as radiation detection pixels 32A, and the remaining pixels 32 are referred to as radiation image acquisition pixels 32B.

In the radiation detector 20 according to the present embodiment, a radiographic image is captured by the radiation image acquisition pixel 32B excluding the radiation detection pixel 32A in the pixel 32. Therefore, the radiation image at the arrangement position of the radiation detection pixel 32A is used. Cannot be obtained. For this reason, in the radiation detector 20 according to the present exemplary embodiment, the radiation detection pixels 32A are arranged so as to be dispersed, and the pixel information of the radiation image at the arrangement position of the radiation detection pixels 32A by the electronic cassette 40 or the console. Is corrected using the pixel information obtained by the radiation image acquisition pixel 32B located around the radiation detection pixel 32A, and a defective pixel correction process is executed.

Here, the radiation detector 20 according to the present embodiment is connected directly to the connection portion between the capacitor 9 and the thin film transistor 10 in the radiation detection pixel 32A, and directly reads out the electric charge accumulated in the capacitor 9. The readout wiring 38 is extended in the predetermined direction (scanning line direction). In the radiation detector 20 according to the present embodiment, one direct readout wiring 38 is assigned to the plurality of radiation detection pixels 32A arranged in the predetermined direction, and the plurality of radiation detection pixels 32A. The connection portion between the capacitor 9 and the thin film transistor 10 is connected to a common (single) direct readout wiring 38.

Each of the direct readout wirings 38 is connected to a signal processing unit having the same configuration as that of the signal processing unit 54A, and the cassette control unit 58 applies the radiation irradiation state based on the information output from the signal processing unit. Is detected.

Since the configuration other than the radiation detector 20 and the operation of the electronic cassette 40 are the same as those in the first embodiment, description thereof is omitted here.

Also in this embodiment, the same effects as those of the first embodiment can be obtained.

As mentioned above, although this invention was demonstrated using each embodiment, the technical scope of this invention is not limited to the range as described in each said 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.

In addition, each of the above embodiments does not limit the invention according to the claims (claims), and all combinations of features described in each embodiment are indispensable for solving means of the invention. Not always. Each embodiment described above includes inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. Even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, as long as an effect is obtained, a configuration from which these some constituent requirements are deleted can be extracted as an invention.

For example, in each of the above embodiments, the case where the present invention is applied to the electronic cassette 40 which is a portable radiographic image capturing apparatus has been described. However, the present invention is not limited to this, and a stationary radiographic image is provided. You may apply to an imaging device.

Further, in each of the above embodiments, the case where a radiation detector having only one radiation-sensitive layer as a scintillator has been described, but the present invention is not limited to this, for example, Instead of the scintillator, a radiation detector that is made of amorphous selenium or the like and that directly converts radiation into electric charges or that has two radiation sensitive layers may be applied.

FIG. 13 shows a configuration example of the radiation detector in this case.

The radiation detector shown in FIG. 13 (A) shows an example in which a radiation sensitive layer 8 ′ made of amorphous selenium is applied instead of the scintillator 8 in the radiation detector 20 according to each of the above embodiments. ing. 13 (B) to 13 (D) show an example in which two scintillators 8A and 8B are provided as radiation sensitive layers. FIGS. 13 (E) to 13 (G) show an example of a case in which a radiation sensitive layer 8A ′ and a radiation sensitive layer 8B ′ made of two amorphous selenium are provided as a radiation sensitive layer. Has been. Further, FIG. 13 (H) to FIG. 13 (J) show an example in which a radiation sensitive layer 8A ′ composed of one scintillator 8B and one amorphous selenium is provided as a radiation sensitive layer. ing. As another example of the direct conversion type radiation sensitive layer, Si (silicon), CdTe (cadmium telluride), or the like may be used instead of amorphous selenium.

In these embodiments, the same effects as those in the above embodiments can be obtained.

In particular, in a form in which two radiation sensitive layers are provided and a dedicated radiation sensitive layer is provided on the TFT substrate 30A for moving image shooting, as schematically shown in FIG. 14 and FIG. Based on the charge obtained by the high-sensitivity radiation detection pixel when performing still image shooting, including high-sensitivity radiation detection pixels and low-sensitivity radiation detection pixels that have different radiation detection sensitivities. Thus, the radiation irradiation start may be detected, and the radiation irradiation stop may be detected based on the charge obtained by the low-sensitivity radiation detection pixel.

In this case, as shown in FIG. 16 as an example, the start of radiation irradiation can be detected at a high speed, and the detection of the stop of radiation irradiation is less likely to cause saturation of the charge accumulated in the pixel. The irradiation stop can be detected.

Also, in each of the above embodiments, no particular mention was made of the timing for starting to capture a still image. On the other hand, as shown in FIG. 17 as an example, moving image shooting is performed based on the electric charge read from the TFT substrate 30A for moving image shooting, and an increase in the radiation dose of the irradiated radiation is performed based on the electric charge. The degree may be derived, and when the degree is equal to or greater than a predetermined threshold, it is possible to determine that the process shifts to still image shooting.

In each of the above embodiments, the case where the pixel for detecting the irradiation state of radiation is provided between the pixels of the TFT substrate 30A has been described. However, the present invention is not limited to this, and is illustrated as an example. As shown in FIG. 18, a pixel for detecting the irradiation state of radiation may be provided in the periphery of the TFT substrate 30A.

In each of the above embodiments, the case where the radiation-sensitive layer of the present invention including CsI is applied has been described. However, the present invention is not limited to this, and other elements such as CsBr are used. A form including a columnar crystal may be applied.

In each of the above embodiments, the case where the cassette control unit 58 and the power supply unit 70 are arranged in the casing 41 of the electronic cassette 40 so as not to overlap the case 42 and the radiation detector has been described. It is not limited. For example, you may arrange | position so that a radiation detector and the cassette control part 58 and the power supply part 70 may overlap.

Although not particularly mentioned in the above embodiments, it is preferable that at least one of the TFT substrate 30A and the TFT substrate 30B is a flexible substrate. Thereby, even when the positions of the end portions of the columnar crystals of the scintillator 8 are not aligned, the adhesion between the scintillator 8 and the TFT substrate stacked on the scintillator 8 can be improved. In this case, as a flexible substrate to be applied, it is preferable to use a substrate using ultra-thin glass by a recently developed float method as a base material in order to improve the radiation transmittance. As for the ultra-thin glass that can be applied at this time, for example, “Asahi Glass Co., Ltd.,“ Successfully developed the world's thinnest 0.1 mm thick ultra-thin glass by the float method ”, [online], [2011 Aug. 20 search], Internet <URL: http://www.agc.com/news/2011/0516.pdf> ”.

Moreover, you may use the organic CMOS sensor which comprised the photoelectric converting film 4 with the material containing an organic photoelectric conversion material as the sensor part 13 of the radiation detector 20, and it is a thin-film transistor as TFT board | substrate 30A, 30B of the radiation detector 20. An organic TFT array sheet in which organic transistors including the organic material 10 are arranged in an array on a flexible sheet may be used. The above organic CMOS sensor is disclosed in, for example, Japanese Patent Application Laid-Open No. 2009-212377. In addition, the organic TFT array sheet described above is, for example, “Nihon Keizai Shimbun,“ The University of Tokyo, “Developing“ Ultra Flexible ”Organic Transistor” ”, [online], [Search May 8, 2011], Internet <URL : Http://www.nikkei.com/tech/trend/article/g=96958A9C93819499E2EAE2E0E48DE2EAE3E3E0E2E3E2E2E2E2E2E2E2; p = 9694E0E7E2E6E0E2E3E2E2E0E2E0> ”

When a CMOS sensor is used as the sensor unit 13 of each radiation detector, the advantage that photoelectric conversion can be performed at a high speed and the result that the substrate can be thinned can suppress radiation absorption when the ISS method is adopted. There is an advantage that it can be suitably applied to mammography photography.

On the other hand, as a defect when a CMOS sensor is used as the sensor unit 13 of each radiation detector, the resistance to radiation is low when a crystalline silicon substrate is used. For this reason, conventionally, there has been a technique for taking measures such as providing an FOP (fiber optical plate) between the sensor unit and the TFT substrate.

Based on this drawback, a technique using a SiC (silicon carbide) substrate as a semiconductor substrate having high resistance to radiation can be applied. Advantages that can be used as an ISS method by using a SiC substrate, and because SiC has a lower internal resistance and a smaller amount of heat generation than Si, it suppresses the amount of heat generation when shooting movies, and raises the temperature of CsI There is an advantage that it is possible to suppress a decrease in sensitivity due to.

As described above, a substrate having high resistance to radiation such as a SiC substrate is generally a wide cap (about 3 eV), and as an example, as shown in FIG. 19, the absorption edge is about 440 nm corresponding to the blue region. Therefore, in this case, a scintillator such as CsI: Tl or GOS that emits light in the green region cannot be used. FIG. 19 shows spectra of various materials when quinacridone is used as the organic photoelectric conversion material.

In contrast, the scintillator that emits light in these green regions has been actively researched due to the sensitivity characteristics of amorphous silicon, and therefore there is a high demand for using the scintillator. For this reason, the scintillator which light-emits in a green area | region can be used by comprising the photoelectric converting film 4 with the material containing the organic photoelectric conversion material which absorbs light emission in a green area | region.

When the photoelectric conversion film 4 is formed of a material containing an organic photoelectric conversion material and the thin film transistor 10 is formed using a SiC substrate, the photoelectric conversion film 4 and the thin film transistor 10 have different sensitivity wavelength regions, and thus the light emitted by the scintillator is emitted. There is no noise of the thin film transistor 10.

Further, if SiC and a material containing an organic photoelectric conversion material are laminated as the photoelectric conversion film 4, in addition to receiving light emission mainly in the blue region, such as CsI: Na, light emission in the green region is also received. As a result, the sensitivity can be improved. In addition, since the organic photoelectric conversion material hardly absorbs radiation, it can be suitably used for the ISS system.

Note that SiC is highly resistant to radiation because it is difficult for nuclear nuclei to be blown away even when exposed to radiation. Develop semiconductor devices that can be used for a long time ", [online], [Search May 8, 2011], Internet <URL: http://www.jaea.go.jp/jari/jpn/publish/01/ff/ ff36 / sic.html> ”.

Moreover, C (diamond), BN, GaN, AlN, ZnO etc. are mentioned as a semiconductor material with high tolerance with respect to radiations other than SiC. These light element semiconductor materials have high radiation resistance because they are mainly wide-gap semiconductors, so they require high energy for ionization (electron-hole pair formation), small reaction cross-sections, This is due to the fact that bonding is strong and atomic displacement is less likely to occur. Regarding this point, for example, “Electronics Research Institute,“ New Development of Nuclear Electronics ”, [online], [Search May 8, 2011], Internet <URL: http: //www.aist .go.jp / ETL / jp / results / bulletin / pdf / 62-10to11 / kobayashi150.pdf> and “Research on Radiation Resistance of Zinc Oxide Electronic Devices”, 2009 Wakasa Bay Energy It is disclosed in “Research Center Public Research Report, March 2010”. Regarding the radiation resistance of GaN, for example, “Tohoku University,“ Evaluation of radiation resistance of gallium nitride device ”, [online], [Search May 8, 2011], Internet <URL: http: // cycgw1 .cyric.tohoku.ac.jp / ~ sakemi / ws2007 / ws / pdf / narita.pdf> ”.

In addition, since GaN has good thermal conductivity as a use other than blue LEDs and has high insulation resistance, ICs are being studied in the field of power systems. As for ZnO, an LED that emits light mainly in the blue to ultraviolet region has been studied.

By the way, when SiC is used, the band gap Eg is changed from about 1.1 eV to about 2.8 eV of Si, so that the light absorption wavelength λ shifts to the short wavelength side. Specifically, since the wavelength λ = 1.24 / Eg × 1000, the sensitivity changes to wavelengths up to about 440 nm. Therefore, when SiC is used, as shown in FIG. 20 as an example, the scintillator emits light in the blue region rather than CsI: Tl (peak wavelength: about 565 nm) that emits light in the green region, as well as CsI: Na (peak wavelength: about 420 nm). This is more suitable as the emission wavelength. Since the phosphor emits blue light well, CsI: Na (peak wavelength: about 420 nm), BaFX: Eu (X is a halogen such as Br and I, peak wavelength: about 380 nm), CaWO ₄ (peak wavelength: about 425 nm) ZnS: Ag (peak wavelength: about 450 nm), LaOBr: Tb, Y ₂ O ₂ S: Tb, and the like are suitable. In particular, BaFX: Eu used in CsI: Na and CR cassettes, and CaWO ₄ used in screens and films are preferably used.

On the other hand, as a CMOS sensor having high resistance to radiation, a CMOS sensor may be configured by using a configuration of Si substrate / thick film SiO ₂ / organic photoelectric conversion material by SOI (Silicon On Insulator).

Technologies that can be applied to this configuration include, for example, “Japan Aerospace Exploration Agency (JAXA) Institute for Space Science,“ High radiation resistance by combining the most advanced consumer SOI technology and radiation resistance technology for space. “Development of functional logic integrated circuit development platform for the first time in the world”, [online], [Search May 8, 2011], Internet <URL: http://www.jaxa.jp/press/2010/11/20101122_soi_j .html> ".

In addition, since the radiation resistance of the film thickness SOI is high in the SOI, examples of the high radiation durability element include a complete separation type thick film SOI and a partial separation type thick film SOI. As for these SOIs, for example, “Patent Office,“ Patent Application Technology Trend Survey Report on SOI (Silicon On Insulator) Technology ”, [online], [Search May 8, 2011], Internet <URL: http://www.jpo.go.jp/shiryou/pdf/gidou-houkoku/soi.pdf> ”.

Even if the thin film transistor 10 or the like of the radiation detector 20 does not have light transmission (for example, a structure in which the active layer 17 is formed of a material having no light transmission such as amorphous silicon), the thin film transistor 10 or the like. Is disposed on a light-transmitting substrate 1 (for example, a flexible substrate made of synthetic resin), and a portion of the substrate 1 where the thin film transistor 10 or the like is not formed is configured to transmit light. It is possible to obtain a radiation detector 20 having optical transparency. Arranging the thin film transistor 10 or the like having a non-light-transmitting structure on the light-transmitting substrate 1 is performed by separating the micro device block manufactured on the first substrate from the first substrate. This can be realized by applying the technology disposed above, specifically, for example, FSA (Fluidic Self-Assembly). The above FSA is, for example, “Toyama University,“ Study on Self-Aligned Placement Technology of Small Semiconductor Blocks ”, [online], [Search May 8, 2011], Internet <URL: http: //www3.u- toyama.ac.jp/maezawa/Research/FSA.html> ”.

The entire disclosure of Japanese Patent Application No. 2011-239681 is incorporated herein by reference.

All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

8, 8A, 8B Scintillator (radiation sensitive layer)
8 ', 8A', 8B 'Radiation sensitive layer 10 Thin film transistor 13 Sensor unit 14 Signal output unit 20 Radiation detector 22 Base 30A TFT substrate (second substrate)
30B TFT substrate (first substrate)
40 Electronic cassette 41 Housing 54A Signal processing unit (second signal processing means)
54B Signal processor (first signal processing means)
58A CPU (detection means, control means)
71A Columnar crystal 71B Non-columnar crystal 94 Binning part (binning setting means)

Claims (12)

1. A light-sensitive layer that generates light corresponding to the irradiated radiation or generates a charge corresponding to the irradiated radiation, is laminated on the radiation-sensitive layer, and the light is generated when the radiation-sensitive layer generates light. A plurality of first pixels including a first photoelectric conversion unit that generates a charge corresponding to the first photoelectric conversion unit and a first switching element for reading out the charge generated by the first photoelectric conversion unit, or When the radiation sensitive layer generates a charge, a first substrate for still image photography provided with a plurality of second pixels provided with a second switching element for reading out the charge, and the radiation sensitive layer The second photoelectric conversion unit and the second photoelectric conversion unit, which are stacked on the surface opposite to the first substrate and generate a charge corresponding to the light when the radiation sensitive layer generates light, A fourth switching element for reading a charge when a plurality of third pixels having a third switching element for reading the generated charge are provided in a matrix or when the radiation sensitive layer generates a charge A radiation detector having a second substrate for moving image shooting in which a plurality of fourth pixels provided in a matrix are provided;
   When performing still image shooting using the first substrate, detection means for detecting a radiation irradiation state based on the electric charge read from the second substrate;
   Control means for controlling to perform still image shooting by the radiation detector based on the detection result by the detection means;
   A radiographic imaging apparatus comprising:
2. The radiographic image capturing apparatus according to claim 1, wherein the second substrate is at least one of a low resolution and a small size as compared with the first substrate.
3. The radiographic image capturing apparatus according to claim 1, wherein the second substrate includes a pixel for detecting an irradiation state of the radiation provided between pixels for capturing a radiographic image.
4. First signal processing means for performing predetermined signal processing on the electric charge read from the first substrate in a state where power is supplied;
   Second signal processing means for performing predetermined signal processing on the electric charges read from the second substrate in a state where power is supplied;
   Further comprising
   The radiographic imaging apparatus according to any one of claims 1 to 3, wherein the control unit controls the power supply to the first substrate to be stopped when the detection unit detects an irradiation start of the radiation. .
5. A binning setting unit configured to selectively set a binning state for combining charges read from the second substrate in units of adjacent pixels and a non-binning state in which the combining is not performed;
   The radiographic image according to any one of claims 1 to 4, wherein the control unit controls the binning setting unit so as to set the binning state when the detection unit detects the start of irradiation of the radiation. Shooting device.
6. The control means controls the charge reading speed from the second substrate to be increased as compared to the case of moving image shooting when the radiation state of the radiation is detected by the detection means. The radiographic imaging device according to any one of the above.
7. Between the first substrate and the second substrate, the surface of the first substrate opposite to the surface on which the radiation sensitive layer is laminated, or the radiation sensitive layer of the second substrate is laminated. A second radiation-sensitive layer that is laminated on a surface opposite to the surface on which the light is irradiated and generates light according to the irradiated radiation or generates a charge according to the irradiated radiation. The radiographic imaging apparatus of any one of Claim 6.
8. The second substrate includes, as the second photoelectric conversion unit, a high-sensitivity photoelectric conversion unit and a low-sensitivity photoelectric conversion unit, each having different light detection sensitivities,
   When the still image shooting is performed using the first substrate, the detection unit detects the start of irradiation of the radiation based on the electric charge obtained by the high-sensitivity photoelectric conversion unit and is obtained by the low-sensitivity photoelectric conversion unit. The radiographic imaging apparatus according to claim 7, wherein the radiation stoppage of the radiation is detected based on the generated charge.
9. The radiation according to any one of claims 1 to 8, wherein the radiation detector is arranged such that the first substrate is disposed on a radiation incident side of the radiation sensitive layer when a still image is captured. Image shooting device.
10. The radiographic imaging apparatus according to any one of claims 1 to 9, wherein the radiation-sensitive layer includes a columnar crystal when generating light corresponding to the irradiated radiation.
11. Computer
    A light-sensitive layer that generates light corresponding to the irradiated radiation or generates a charge corresponding to the irradiated radiation, is laminated on the radiation-sensitive layer, and the light is generated when the radiation-sensitive layer generates light. A plurality of first pixels including a first photoelectric conversion unit that generates a charge corresponding to the first photoelectric conversion unit and a first switching element for reading out the charge generated by the first photoelectric conversion unit, or When the radiation sensitive layer generates a charge, a first substrate for still image photography provided with a plurality of second pixels provided with a second switching element for reading out the charge, and the radiation sensitive layer The second photoelectric conversion unit and the second photoelectric conversion unit, which are stacked on the surface opposite to the first substrate and generate a charge corresponding to the light when the radiation sensitive layer generates light, A fourth switching element for reading a charge when a plurality of third pixels having a third switching element for reading the generated charge are provided in a matrix or when the radiation sensitive layer generates a charge When performing still image shooting using the first substrate by a radiation detector having a second substrate for moving image shooting in which a plurality of fourth pixels provided in a matrix are read out from the second substrate Detecting means for detecting the irradiation state of radiation based on the generated charge;
    Control means for controlling to perform still image shooting by the radiation detector based on the detection result by the detection means;
    Program to function as.
12. A light-sensitive layer that generates light corresponding to the irradiated radiation or generates a charge corresponding to the irradiated radiation, is laminated on the radiation-sensitive layer, and the light is generated when the radiation-sensitive layer generates light. A plurality of first pixels including a first photoelectric conversion unit that generates a charge corresponding to the first photoelectric conversion unit and a first switching element for reading out the charge generated by the first photoelectric conversion unit; or When the radiation sensitive layer generates a charge, the first substrate for still image photography provided with a plurality of second pixels provided with a second switching element for reading out the charge, and the radiation sensitive layer The second photoelectric conversion unit and the second photoelectric conversion unit, which are stacked on the surface opposite to the first substrate and generate a charge corresponding to the light when the radiation sensitive layer generates light, A fourth switching element for reading a charge when a plurality of third pixels having a third switching element for reading the generated charge are provided in a matrix or when the radiation sensitive layer generates a charge When performing still image shooting using the first substrate by a radiation detector having a second substrate for moving image shooting in which a plurality of fourth pixels provided in a matrix are read out from the second substrate A detection step of detecting a radiation irradiation state based on the generated charge;
    Based on the detection result of the detection step, a control step for controlling to perform still image shooting by the radiation detector;
    A radiographic imaging method comprising:

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