JP2012233781A - Radiation image detector and radiographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a satisfactory energy subtraction image by a simple device constitution.SOLUTION: A radiation image detector 3 has: a fluorescent body 30 including a first fluorescence composition which emits first fluorescence by absorbing mainly low energy components of irradiated radioactive ray and a second fluorescence composition which emits second fluorescence by absorbing mainly high energy components of the radioactive ray; an array 41 of a first pixel for detecting the first fluorescence; a first sensor panel 32 disposed on the incident side of the radioactive ray of the fluorescent body; an array 51 of a second pixel for detecting the second fluorescence; and a second sensor panel 32 disposed opposite to the first sensor panel across the fluorescent body. As for the content rates of the first and second fluorescence compositions in the fluorescent body, the content rate of the first fluorescence composition is high on the side of the first sensor panel and the rate of the second fluorescence composition is high on the side of the second senor panel.

Description

  The present invention relates to a radiation image detection device and a radiation imaging apparatus including the radiation image detection device.

  In recent years, a radiological image detection apparatus that detects a radiographic image and generates digital image data has been put into practical use, and is rapidly spreading for the reason that an image can be immediately confirmed as compared with a conventional imaging plate. There are various types of radiological image detection apparatuses, and one of them is an indirect conversion type.

  An indirect conversion type radiological image detection apparatus includes a scintillator (phosphor) formed of a fluorescent composition that emits fluorescence by radiation exposure, and an array of pixels that detect the fluorescence generated in the scintillator and convert it into an electrical signal on a substrate. And a provided sensor panel. The radiation transmitted through the subject is converted into light by the scintillator, and the fluorescence of the scintillator is converted into an electrical signal by the pixel of the sensor panel, thereby generating image data.

  Then, image data based on a low energy component of radiation and image data based on a high energy component are acquired, and an image in which a specific structure of a subject (for example, a patient's organ, bone, or blood vessel) is emphasized is obtained. An indirect conversion type radiological image detection apparatus for performing so-called energy subtraction is known (see, for example, Patent Document 1).

  The radiological image detection apparatus described in Patent Document 1 includes a scintillator obtained by uniformly mixing two types of fluorescent materials A and B, two sensor panels disposed opposite to each other with the scintillator interposed therebetween, It consists of two filters that are respectively interposed between the sensor panel and the scintillator. One of the fluorescent materials A and B mainly absorbs a low-energy component of radiation, the other mainly absorbs a high-energy component of radiation, and has different peak wavelengths of fluorescence emitted by absorbing radiation. One filter blocks the fluorescence of the fluorescent material A and transmits the fluorescence of the other fluorescent material B, and the other filter blocks the fluorescence of the fluorescent material B and transmits the fluorescence of the other fluorescent material A. It is configured to let you. With these filters, one sensor panel receives only the fluorescence of the fluorescent material A and generates image data based on the low-energy component of the radiation, and the other sensor panel receives only the fluorescence of the fluorescent material B. Thus, image data based on the high energy component of the radiation is generated.

JP-A-7-120557

  In the radiological image detection apparatus described in Patent Document 1, a filter is required to select the fluorescence of the fluorescent material A and the fluorescence of the fluorescent material B. Without the filter, the fluorescence of the fluorescent material A and the fluorescent material Contamination with B fluorescence occurs, and the energy subtraction image is deteriorated.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a radiographic image detection apparatus and a radiographic apparatus that can obtain a good energy subtraction image with a simple apparatus configuration.

(1) A first fluorescent composition that mainly absorbs a low energy component of irradiated radiation and emits first fluorescence, and a second that mainly absorbs a high energy component of the radiation and emits second fluorescence. A phosphor having a phosphor composition; a first sensor panel having a first pixel array for detecting the first fluorescence; and disposed on a radiation incident side of the phosphor; And a second sensor panel disposed opposite to the first sensor panel with the phosphor interposed therebetween, wherein the phosphor in the phosphor includes the second pixel array. The content ratio of the first fluorescent composition and the second fluorescent composition is higher in the first fluorescent composition on the first sensor panel side and in the second sensor panel side. A radiological image detection apparatus having a high fluorescent composition.
(2) Using the radiographic image detection apparatus according to (1), the first image data generated by the first sensor panel, and the second image data generated by the second sensor panel, A radiation imaging apparatus comprising: an image processing unit that generates an energy subtraction image.

  According to the present invention, the first fluorescence of the first phosphor composition is mainly on the first sensor panel side of the phosphor, and the second fluorescence of the second phosphor composition is mainly of the phosphor. It occurs on the second sensor panel side. The first fluorescence is attenuated by absorption or the like by the phosphor itself until it reaches the second sensor panel, and the second fluorescence is similarly reduced until it reaches the first sensor panel. Attenuated. Therefore, in the first sensor panel, the first fluorescence is mainly detected and image data based on the low energy component of the radiation is generated, and in the second sensor panel, the second fluorescence is mainly detected and the radiation is detected. Image data based on the high energy component of is generated. In this manner, fluorescence received by each sensor panel can be selected without using a filter, and a good energy subtraction image can be obtained with a simple device configuration.

It is a figure which shows typically the structure of an example of the radiographic image detection apparatus and radiography apparatus for describing embodiment of this invention. It is a control block diagram of the radiography apparatus of FIG. It is a figure which shows typically the structure of the radiographic image detection apparatus of FIG. It is a graph which shows typically conversion of the content rate of the 1st fluorescence composition and 2nd fluorescence composition which form the fluorescent substance contained in the radiographic image detection apparatus of FIG. It is a figure which shows typically the structure of the other example of the radiographic image detection apparatus for describing embodiment of this invention. It is a figure which shows typically the structure of the other example of the radiographic image detection apparatus for describing embodiment of this invention. It is a figure which shows typically the structure of the other example of the radiographic image detection apparatus for describing embodiment of this invention. It is a figure which shows typically the structure of the other example of the radiographic image detection apparatus for describing embodiment of this invention.

  FIG. 1 shows a configuration of an example of a radiation image detection apparatus and a radiation imaging apparatus for explaining an embodiment of the present invention, and FIG. 2 shows a control block of the radiation imaging apparatus of FIG.

  The X-ray imaging apparatus 1 is an X-ray diagnostic apparatus that images a subject (patient) H in a standing position, and is disposed opposite to the X-ray source 2 and an X-ray source 2 that emits cone beam X-rays to the subject H. The X-ray image detection apparatus 3 that detects X-rays transmitted from the X-ray source 2 through the subject H and generates image data, and the exposure operation and X-ray image of the X-ray source 2 based on the operation of the operator The operation is broadly divided into a console 4 that controls the imaging operation of the detection device 3 and processes image data acquired by the X-ray image detection device 3. The X-ray source 2 is held by an X-ray source holding device 5 suspended from the ceiling. The X-ray image detection apparatus 3 is held by a stand 6 installed on the floor.

  The X-ray source 2 is emitted from the X-ray tube 12 and the X-ray tube 12 that generates X-rays according to the high voltage applied from the high voltage generator 11 based on the control of the X-ray source control unit 10. The X-ray includes a collimator unit 14 having a movable collimator 13 that limits an irradiation field so as to shield a portion that does not contribute to the inspection area of the subject H.

  The X-ray source holding device 5 is connected to a carriage unit 16 configured to be movable in a horizontal direction (z direction) along a ceiling rail 15 installed on the ceiling, and extends downward from the carriage unit 16. A plurality of support columns 17, a drive mechanism for moving the carriage unit 16 along the ceiling rail, and a drive mechanism for expanding and contracting the support columns 17 are provided. The X-ray source 2 is attached to the distal end portion of the column portion 17. When the X-ray source holding device 5 moves along the ceiling rail 15, the distance SID in the horizontal direction between the X-ray source 2 and the X-ray image detection device 3 is changed, and the support column 17 expands and contracts. As a result, the position of the X-ray source 2 in the vertical direction is changed. Both drive mechanisms are controlled by the console 4 based on an operator's setting operation.

  The stand 6 includes a main body 18 installed on the floor, a holding portion 19 attached to the main body 18 so as to be movable in the vertical direction, and a drive mechanism for moving the holding portion 19 up and down. The X-ray image detection device 3 is attached to the holding unit 19. The drive mechanism is controlled by the control device 20 of the console 4 described later based on the setting operation by the operator.

The console 4 is provided with a control device 20 including a CPU, a ROM, a RAM, and the like.
The control device 20 includes an input device 21 through which an operator inputs an imaging instruction and the content of the instruction, and an image processing unit 22 that processes the image data acquired by the X-ray image detection device 3 to generate an X-ray image. , An image storage unit 23 for storing X-ray images, a monitor 24 for displaying X-ray images and the like, and an interface (I / F) 25 connected to each unit of the X-ray imaging apparatus 1. The control device 20, input device 21, image processing unit 22, image storage unit 23, monitor 24, and I / F 25 are connected via a bus 26.

  By operating the input device 21, the distance between the X-ray source 2 and the X-ray image detection device 3 (imaging distance) SID, X-ray imaging conditions such as tube voltage, imaging timing, and the like are input. Based on the horizontal position of the X-ray source 2 supplied from the X-ray source holding device 5, the control device 20 moves the X-ray source 2 to a position corresponding to the input imaging distance SID. The radiation source holding device 5 is driven. Further, the control device 20 moves the X-ray source 2 to the vertical position facing the X-ray image detection device 3 based on the vertical position of the X-ray image detection device 3 supplied from the stand 6. The radiation source holding device 5 is driven.

  The X-ray image detection device 3 includes a scintillator (phosphor) 30 containing a phosphor composition that emits fluorescence by X-ray exposure, a first sensor panel 31 and a second sensor panel 31 disposed so as to sandwich the scintillator 30 therebetween. And a sensor panel 32.

  The X-ray image detection apparatus 3 of this example is attached to the holding unit 19 (see FIG. 1) so that the first sensor panel 31 is located on the X-ray source 2 side. The light enters the X-ray image detection device 3 from the panel 31 side. X-rays incident on the X-ray image detection apparatus 3 (hereinafter referred to as incident X-rays) are transmitted through the first sensor panel 31 and incident on the scintillator 30, and fluorescence is generated in the scintillator 30 exposed to X-rays. The first sensor panel 31 detects a part of the fluorescence generated in the scintillator 30 and generates image data corresponding to the detected X-ray. The second sensor panel 32 also detects a part of the fluorescence generated in the scintillator 30 and generates image data corresponding to the detected X-ray.

  Both image data generated by the first sensor panel 31 and the second sensor panel 32 are sent to the image processing unit 22 (see FIG. 2) of the console 4, respectively. For example, the image processing unit 22 appropriately weights both image data, and subtracts the other image data from one image data to generate an energy subtraction image.

  FIG. 3 shows the configuration of the X-ray image detection apparatus 3.

  First, the first sensor panel 31 and the second sensor panel 32 of the X-ray image detection apparatus 3 will be described.

  The first sensor panel 31 includes an insulating substrate 40 such as a glass substrate and an array of first pixels 41 provided on the insulating substrate 40. Each of the first pixels 41 includes a photoelectric conversion element 42 that receives the fluorescence of the scintillator 30 and generates a charge, and a read circuit unit 43 that reads out the charge generated in the photoelectric conversion element.

  In this example, the readout circuit section 43 is formed of a thin film transistor (TFT) and is formed on the insulating substrate 40. The photoelectric conversion element 42 is a thin film photodiode in which a photoelectric conversion film is provided between a pair of electrodes, and is formed on the insulating substrate 40. Amorphous silicon (a-Si) is used for the photoelectric conversion film, and the spectral sensitivity of the a-Si photodiode is in the green wavelength range (495 nm to 570 nm) with a peak wavelength of 550 nm to 600 nm. Is widely distributed up to the blue wavelength region. In the present specification, the blue wavelength region includes the near ultraviolet region, and refers to a region having a wavelength of 200 nm to 495 nm.

  The charges generated in each of the photoelectric conversion elements 42 are sequentially read out through the corresponding readout circuit units 43, and converted into electric signals in a signal processing unit (not shown) to which these readout circuit units 43 are connected. Digital image data is generated.

  In the illustrated example, the photoelectric conversion element 42 and the readout circuit portion 43 are formed in different layers, and the layer of the photoelectric conversion element 42 is disposed on the scintillator 30 side. Note that the photoelectric conversion element 42 and the readout circuit unit 43 may be formed in one and the same layer, or the layer of the readout circuit unit 43 and the layer of the photoelectric conversion element 42 are formed in this order from the scintillator 30 side. However, as shown in the illustrated example, the photoelectric conversion element 42 and the readout circuit unit 43 are formed in different layers, whereby the size of the photoelectric conversion element 42 can be increased. The photoelectric conversion element 42 is formed in this order from the scintillator 13 side to the readout circuit unit 43 layer, so that the photoelectric conversion element 42 can be disposed closer to the scintillator 30 and the sensitivity is improved. To do.

  The second sensor panel 32 includes an insulating substrate 50 such as a glass substrate and an array of second pixels 51 provided on the insulating substrate 50. Each of the second pixels 51 includes a photoelectric conversion element 52 and a readout circuit unit 53. The configurations of the photoelectric conversion element 52 and the readout circuit unit 53 are the same as the configurations of the photoelectric conversion element 42 and the readout circuit unit 43 in the first pixel 41, and a description thereof will be omitted.

  Next, the scintillator 30 will be described.

  The scintillator 30 is formed by a mixture of the first fluorescent composition and the second fluorescent composition. The first fluorescent composition has a K absorption edge in a relatively low energy region, and mainly absorbs low energy components of X-rays to emit fluorescence. The second fluorescent composition has a K absorption edge in a higher energy region than the fluorescent composition forming the first scintillator 31, and absorbs a higher energy component of X-rays than the first fluorescent composition. Emits fluorescence.

In this example, europium-activated barium fluorohalide (BaFX: Eu (X is a halogen such as Cl, Br, or I)) is used as the first fluorescent composition, and calcium tungstate (CaWO) is used as the second fluorescent composition. ₄ ) is used. In this case, the peak wavelength of fluorescence (380 nm) emitted from the first fluorescent composition (BaFX: Eu) and the peak wavelength of fluorescence (425 nm) emitted from the second fluorescent composition (CaWO ₄ ) are both blue. In the wavelength range of.

  FIG. 4 shows the content of the first fluorescent composition and the second fluorescent composition in the scintillator 30.

  In the scintillator 30, the content ratios of the first fluorescent composition and the second fluorescent composition are determined in the thickness direction of the scintillator 30 (first sensor panel 31 and second sensor panel 32 facing each other with the scintillator 30 interposed therebetween. In the opposite direction). On the X-ray incident side (first sensor panel 31 side) of the scintillator 30, the content ratio of the first fluorescent composition is higher than that of the second fluorescent composition, and is opposite to the X-ray incident side of the scintillator 30. On the side (second sensor panel 32 side), the content of the second fluorescent composition is higher than that of the first fluorescent composition.

  The change in the content ratio of the first fluorescent composition and the second fluorescent composition in the scintillator 30 is, for example, a resin that transmits light to each particle of the first fluorescent composition and the second fluorescent composition. And the resin is cured to produce a scintillator, wherein the particle diameter of the first fluorescent composition and the particle diameter of the second fluorescent composition are made different from each other under appropriate stirring conditions. The particles of any of the fluorescent compositions can be obtained by making the particles relatively easy to settle.

  The contents of the first fluorescent composition and the second fluorescent composition may change linearly in the thickness direction of the scintillator 30, or may change nonlinearly, or change stepwise. May be.

  In the X-ray image detection apparatus 3 configured as described above, incident X-rays pass through the first sensor panel 31 and enter the scintillator 30. On the X-ray incident side of the scintillator 30, that is, on the first sensor panel 31 side, the content of the first fluorescent composition that mainly absorbs the low-energy component of X-rays is relatively high. On the one sensor panel 31 side, low energy components of incident X-rays are mainly absorbed. Then, the fluorescence Lb1 corresponding to the absorbed X-rays is generated on the first sensor panel 31 side of the scintillator 30, and the fluorescence Lb1 is detected by the first sensor panel 31. Thereby, image data based on the low energy component of the incident X-ray is generated.

  On the other hand, the high energy component of incident X-rays is not absorbed on the first sensor panel 31 side where the content of the first fluorescent composition is high in the scintillator 30, but is deep in the scintillator 30, that is, the first fluorescent composition. It reaches the second sensor panel 32 side where the content rate of the second fluorescent composition that absorbs more high-energy components of X-rays than the object is relatively high, and is absorbed there. Then, the fluorescence Lb2 corresponding to the absorbed X-rays is generated on the second sensor panel 32 side of the scintillator 30, and the fluorescence Lb2 is detected by the second sensor panel 32. Thereby, image data based on the high energy component of incident X-rays is generated.

Here, the peak wavelength (380 nm) of fluorescence emitted from the first fluorescent composition (BaFX: Eu) and the peak wavelength (425 nm) of fluorescence emitted from the second fluorescent composition (CaWO ₄ ) are both blue. The fluorescence Lb2 that is in the wavelength range and is generated on the second sensor panel side 32 of the scintillator 30 by the high energy component of the incident X-rays can also be detected by the first sensor panel 31, but the fluorescence Lb2 Before reaching the sensor panel 31, it is attenuated by absorption by the scintillator 30 itself. Therefore, in the first sensor panel 31, the fluorescence Lb2 is prevented from being mixed and detected in the fluorescence Lb1 generated on the first sensor panel 31 side of the scintillator 30 due to the low energy component of the incident X-ray. Thereby, in the image data based on the low energy component of the incident X-ray, the influence of the high energy component of the incident X-ray is reduced.

  Similarly, the fluorescence Lb1 can also be detected by the second sensor panel 32, but the fluorescence Lb1 is attenuated by absorption by the scintillator 30 itself before reaching the second sensor panel 32. Therefore, in the second sensor panel 32, the fluorescence Lb1 is prevented from being detected by being mixed with the fluorescence Lb2. Thereby, in the image data based on the high energy component of the incident X-ray, the influence of the low energy component of the incident X-ray is reduced.

  As described above, the fluorescence Lb1 of the first fluorescent composition is mainly on the first sensor panel 31 side of the scintillator 30, and the fluorescence Lb2 of the second fluorescent composition is mainly on the second side of the scintillator 30. This occurs on the sensor panel 32 side. The fluorescence Lb1 is attenuated by absorption or the like by the scintillator 30 itself until it reaches the second sensor panel 32, and the fluorescence Lb2 is similarly attenuated until it reaches the first sensor panel 31. The Therefore, in the first sensor panel 31, the fluorescence Lb1 is mainly detected and image data based on the low energy component of the radiation is generated, and in the second sensor panel 32, the fluorescence Lb2 is mainly detected and the high level of the radiation is detected. Image data based on the energy component is generated. Thus, the fluorescence received by the sensor panels 31 and 32 can be selected without using a filter, and a good energy subtraction image can be obtained with a simple device configuration.

  The insulating substrates 40 and 50 included in the first sensor panel 31 and the second sensor panel 32 are not limited to glass substrates but may be flexible substrates made of resin materials. In addition, although an inorganic semiconductor material such as a-Si is typically used for the TFTs constituting the readout circuit portions 43 and 53, an organic semiconductor material or an amorphous oxide semiconductor material can also be used. These materials will be described later.

  FIG. 5 shows another example of the radiation image detection apparatus for explaining the embodiment of the present invention. In addition, description is abbreviate | omitted or simplified by attaching | subjecting a common code | symbol to the element which is common in the X-ray image detection apparatus 3 mentioned above.

  An X-ray image detection apparatus 103 shown in FIG. 5 includes a scintillator 130, a first sensor panel 31 and a second sensor panel 32 that are arranged so as to sandwich the scintillator 130, and the scintillator 130 and the first sensor panel. 31 and a second filter 134 provided between the scintillator 130 and the second sensor panel 32.

  The scintillator 130 is formed by a mixture of the first fluorescent composition and the second fluorescent composition. The first fluorescent composition has a K absorption edge in a relatively low energy region, and mainly absorbs low energy components of X-rays to emit fluorescence. The second fluorescent composition has a K absorption edge in a higher energy region than the fluorescent composition forming the first scintillator 31, and absorbs a higher energy component of X-rays than the first fluorescent composition. And the peak wavelength of the fluorescence is in a second wavelength region that is out of the first wavelength region where the peak wavelength of the fluorescence of the first fluorescent composition is.

In this example, europium activated barium fluorohalide (BaFX: Eu) is used as the first fluorescent composition, and terbium activated gadolinium oxide (Gd ₂ O ₂ S: Tb) is used as the second fluorescent composition. . In this case, the fluorescence peak wavelength (380 nm) emitted from the first fluorescent composition (BaFX: Eu) is in the blue wavelength range, and the fluorescence emitted from the second fluorescent composition (Gd ₂ O ₂ S: Tb). The peak wavelength (545 nm) is in the green wavelength region.

  In the scintillator 130, the content ratios of the first fluorescent composition and the second fluorescent composition are the same as those in the second fluorescent composition on the X-ray incident side (first sensor panel 31 side) in the scintillator 130. Compared to the first fluorescent composition, the content of the first fluorescent composition is higher than the first fluorescent composition on the side opposite to the X-ray incident side (second sensor panel 32 side) in the scintillator 130. The content of the composition is high.

The first filter 133 selectively blocks the light in the green wavelength region having the fluorescence peak wavelength of the second fluorescent composition (Gd ₂ O ₂ S: Tb), so that the first fluorescent composition ( This is a filter that transmits light in the blue wavelength range having a peak wavelength of fluorescence of BaFX: Eu). The second filter 134 is a filter that selectively blocks light in the green wavelength range and transmits light in the blue wavelength range. As the first filter 133 and the second filter 134, a color filter that selectively absorbs light in a specific wavelength range can be used, but in this example, light in a specific wavelength range is used. A selectively reflecting dichroic filter is used.

  In the X-ray image detection apparatus 103 configured as described above, incident X-rays pass through the first sensor panel 31 and enter the scintillator 130. On the X-ray incident side of the scintillator 130, that is, the first sensor panel 31 side, the content of the first fluorescent composition that mainly absorbs the low energy component of the X-ray is relatively high. On the one sensor panel 31 side, low energy components of incident X-rays are mainly absorbed. Then, on the first sensor panel 31 side of the scintillator 130, the fluorescence Lb in the blue wavelength region corresponding to the absorbed X-rays is generated, and this fluorescence Lb passes through the first filter 133 and passes through the first sensor 133. Detected by panel 31. Thereby, image data based on the low energy component of the incident X-ray is generated.

  On the other hand, the high energy component of incident X-rays is not absorbed on the first sensor panel 31 side where the content of the first fluorescent composition is high in the scintillator 130, but is deep in the scintillator 130, that is, the first fluorescent composition. It reaches the second sensor panel 32 side where the content rate of the second fluorescent composition that absorbs more high-energy components of X-rays than the object is relatively high, and is absorbed there. Then, on the second sensor panel 32 side of the scintillator 130, fluorescence Lg in the green wavelength range corresponding to the absorbed X-rays is generated, and this fluorescence Lg passes through the second filter 134 and is transmitted to the second sensor. Detected by panel 32. Thereby, image data based on the high energy component of incident X-rays is generated.

  Here, as described above, the photoelectric conversion element including the a-Si photodiode included in each of the first pixel 41 of the first sensor panel 31 and the second pixel 51 of the second sensor panel 32 has a visible region. Have wide spectral sensitivity. Therefore, the fluorescence Lg generated on the second sensor panel side 32 of the scintillator 130 by the high energy component of the incident X-rays can be detected also by the first sensor panel 31, but the fluorescence Lg is transmitted to the first sensor panel. In the meantime, the light is attenuated by absorption by the scintillator 130 itself, and further reflected by the first filter 133 that reflects light in the green wavelength region. Therefore, in the first sensor panel 31, the fluorescence Lg is prevented from being detected by being mixed with the fluorescence Lb generated on the first sensor panel 31 side of the scintillator 130 due to the low energy component of the incident X-rays. Thereby, in the image data based on the low energy component of the incident X-ray, the influence of the high energy component of the incident X-ray is reduced.

  Similarly, the fluorescence Lb generated on the first sensor panel side 31 of the scintillator 130 by the low energy component of the incident X-rays can be detected by the second sensor panel 32, but the fluorescence Lb is detected by the second sensor panel. The light is attenuated by absorption by the scintillator 130 itself until reaching 32, and further reflected by the second filter 134 that reflects light in the blue wavelength region. Therefore, in the second sensor panel 32, the fluorescence Lb is prevented from being detected by being mixed with the fluorescence Lg generated on the second sensor panel 32 side of the scintillator 130 due to the high energy component of the incident X-ray. Thereby, in the image data based on the high energy component of the incident X-ray, the influence of the low energy component of the incident X-ray is reduced.

  Further, the fluorescence Lg reflected by the first filter 133 is detected by the second sensor panel 32, and the fluorescence Lb reflected by the second filter 134 is detected by the first sensor panel 31. . Thereby, the sensitivity in the 1st sensor panel 31 and the 2nd sensor panel 32 improves.

  FIG. 6 shows another example of the radiation image detection apparatus for explaining the embodiment of the present invention. Note that elements common to the above-described X-ray image detection apparatuses 3 and 103 are denoted by common reference numerals, and description thereof is omitted or simplified.

  The X-ray image detection apparatus 203 shown in FIG. 6 includes a scintillator 130, and a first sensor panel 231 and a second sensor panel 232 arranged so as to sandwich the scintillator 130 therebetween.

  The first sensor panel 231 includes an insulating substrate 40 and an array of first pixels 241 provided on the insulating substrate 40. Each of the first pixels 241 includes a photoelectric conversion element 242 and a reading circuit unit 43 for reading charges generated in the photoelectric conversion element.

  In the first sensor panel 231 of this example, the readout circuit unit 43 is made of a thin film transistor (TFT) and is formed on the insulating substrate 40. The photoelectric conversion element 242 is a thin film photodiode in which a photoelectric conversion film is provided between a pair of electrodes, and is formed on the insulating substrate 40. The photoelectric conversion film absorbs light in the blue wavelength region having the peak wavelength of the first fluorescent composition (BaFX: Eu) contained in the scintillator 130 and generates an electric charge (hereinafter referred to as “electric photoelectric conversion film”). Blue absorption OPC (Organic photoelectric conversion) film) is used. Since the OPC film generally has a sharp absorption spectrum, the photoelectric conversion element 242 has spectral sensitivity substantially only in the blue wavelength region. In addition, due to the sharp absorption spectrum of the OPC film, the photoelectric conversion element using the OPC film hardly absorbs X-rays, so that it has excellent X-ray resistance and noise generated by absorbing X-rays. Is suppressed.

  As the blue absorbing OPC film, for example, an OPC film described in JP-A-2009-218599 can be used.

The second sensor panel 232 is configured in the same manner as the first sensor panel 231 and includes an insulating substrate 50 and an array of second pixels 251 provided on the insulating substrate. Each of the second pixels 251 includes a photoelectric conversion element 252 and a readout circuit unit 53. The photoelectric conversion element 252 is a thin film photodiode in which a photoelectric conversion film is provided between a pair of electrodes, and is formed on the insulating substrate 50. The photoelectric conversion film absorbs light in a green wavelength region having a peak wavelength of the second fluorescent composition (Gd ₂ O ₂ S: Tb) contained in the scintillator 130 and generates an electric charge. A conversion film (hereinafter referred to as a green absorption OPC (Organic photoelectric conversion) film) is used. Since the OPC film generally has a sharp absorption spectrum, the photoelectric conversion element 252 has spectral sensitivity substantially only in the green wavelength region.

  As the green absorption OPC film, for example, an OPC film using quinacridone described in JP-A-2009-32854 can be used.

  In the X-ray image detection apparatus 203 configured as described above, incident X-rays pass through the first sensor panel 231 and enter the scintillator 130. On the X-ray incident side of the scintillator 130, that is, on the first sensor panel 231 side, the content of the first fluorescent composition that mainly absorbs the low energy component of X-rays is relatively high. On the one sensor panel 231 side, low energy components of incident X-rays are mainly absorbed. Then, on the first sensor panel 231 side of the scintillator 130, fluorescence Lb in a blue wavelength region corresponding to the absorbed X-rays is generated, and this fluorescence Lb is detected by the first sensor panel 231. Thereby, image data based on the low energy component of the incident X-ray is generated.

  On the other hand, the high energy component of incident X-rays is not absorbed on the first sensor panel 231 side where the content of the first fluorescent composition is high in the scintillator 130, but is deep in the scintillator 130, that is, the first fluorescent composition. It reaches the second sensor panel 232 side where the content rate of the second fluorescent composition that absorbs more high-energy components of X-rays than the object is relatively high, and is absorbed there. Then, on the second sensor panel 232 side of the scintillator 130, fluorescence Lg in the green wavelength region corresponding to the absorbed X-rays is generated, and this fluorescence Lg is detected by the second sensor panel 232. Thereby, image data based on the high energy component of incident X-rays is generated.

  Here, the organic photoelectric conversion element 242 included in the first pixel 241 of the first sensor panel 231 has spectral sensitivity substantially only in the blue wavelength region. Therefore, the fluorescence Lg in the green wavelength region generated on the second sensor panel side 32 of the scintillator 130 by the high energy component of the incident X-ray is not detected by the first sensor panel 231. Thereby, in the image data based on the low energy component of the incident X-ray, the influence of the high energy component of the incident X-ray is reduced.

  Similarly, the organic photoelectric conversion element 252 included in the second pixel 251 of the second sensor panel 232 has spectral sensitivity substantially only in the green wavelength region. The fluorescence Lb in the blue wavelength region generated on the first sensor panel side 231 of the scintillator 130 by the low energy component of the incident X-ray is not detected by the second sensor panel 232. Thereby, in the image data based on the high energy component of the incident X-ray, the influence of the low energy component of the incident X-ray is reduced.

  FIG. 7 shows another example of a radiological image detection apparatus for explaining an embodiment of the present invention. Note that elements common to the above-described X-ray image detection apparatuses 3, 103, and 203 are denoted by common reference numerals, and description thereof is omitted or simplified.

  The X-ray image detection apparatus 303 shown in FIG. 7 includes a scintillator 30 and a first sensor panel 331 and a second sensor panel 332 arranged so as to sandwich the scintillator 30 therebetween.

The scintillator 30 is formed of a mixture of a first fluorescent composition and a second fluorescent composition. As the first fluorescent composition, europium-activated barium fluorohalide (BaFX: Eu (X is Cl or Br). And halogens such as I)), and calcium tungstate (CaWO ₄ ) is used as the second fluorescent composition. In this case, the peak wavelength of fluorescence (380 nm) emitted from the first fluorescent composition (BaFX: Eu) and the peak wavelength of fluorescence (425 nm) emitted from the second fluorescent composition (CaWO ₄ ) are both blue. In the wavelength range of.

  The first sensor panel 331 includes a semiconductor substrate 340 and an array of first pixels 341 provided on the semiconductor substrate 340.

  In the first sensor panel 331 of this example, the semiconductor substrate 340 is formed of a semiconductor material having a band gap of 2.8 eV or more, and has an absorption characteristic for light in the blue wavelength region. Examples of such semiconductor materials include SiC (band gap: 2.8 eV), ZnO (band gap: 3.2 eV), GaN (band gap: 3.4 eV), and the like.

  Each of the first pixels 341 includes a photoelectric conversion element 342 such as a photodiode that receives the fluorescence of the scintillator 30 and generates a charge, and a CCD (Charge Coupled Device) for reading out the charge generated in the photoelectric conversion element 343. And a readout circuit unit 343 such as CMOS (Complementary Metal Oxide Semiconductor). The photoelectric conversion element 342 and the readout circuit portion 343 that form the first pixel 341 are both formed over the semiconductor substrate 340. In this manner, the photoelectric conversion element 342 formed on the semiconductor substrate 340 having absorption characteristics for light in the blue wavelength region has spectral sensitivity only substantially in the blue wavelength region.

  Note that single crystal Si is typically used for the semiconductor substrate on which the photoelectric conversion element and the readout circuit portion are formed. In this example, the semiconductor substrate 340 has a band gap of single crystal Si. A semiconductor material such as SiC larger than the band gap of 1.1 eV is used, and the X-ray resistance of the photoelectric conversion element 342 and the readout circuit portion 343 formed on the semiconductor substrate 340 is formed on the single crystal Si semiconductor substrate. Excellent compared to things. Since the first sensor panel 331 is disposed on the X-ray incident side and directly exposed to the incident X-ray, it is preferable that the photoelectric conversion element 342 and the readout circuit unit 343 have excellent X-ray resistance. A readout circuit unit 343 such as a CCD or CMOS formed on the semiconductor substrate 340 is superior in terms of readout speed as compared with a readout circuit unit composed of TFTs formed on a glass substrate.

  The second sensor panel 332 is configured in the same manner as the first sensor panel 331, and includes a semiconductor substrate 350 and an array of second pixels 351 provided on the semiconductor substrate 350. The semiconductor substrate 350 is formed of a semiconductor material having a band gap of 2.8 eV or more, and has an absorption characteristic for light in a blue wavelength region. Each of the second pixels 351 includes a photoelectric conversion element 352 and a readout circuit portion 353, and both the photoelectric conversion element 352 and the readout circuit portion 353 are formed on the semiconductor substrate 350. The photoelectric conversion element 352 formed on the semiconductor substrate 350 having absorption characteristics with respect to light in the blue wavelength region has spectral sensitivity substantially only in the blue wavelength region.

  In the X-ray image detection apparatus 303 configured as described above, incident X-rays pass through the first sensor panel 331 and enter the scintillator 30. On the X-ray incident side of the scintillator 30, that is, on the first sensor panel 31 side, the content of the first fluorescent composition that mainly absorbs the low-energy component of X-rays is relatively high. On the one sensor panel 331 side, low energy components of incident X-rays are mainly absorbed. Then, the fluorescence Lb1 corresponding to the absorbed X-rays is generated on the first sensor panel 31 side of the scintillator 30, and this fluorescence Lb1 is detected by the first sensor panel 331. Thereby, image data based on the low energy component of the incident X-ray is generated.

  On the other hand, the high energy component of incident X-rays is not absorbed on the first sensor panel 331 side where the content of the first fluorescent composition is high in the scintillator 30, but is deep in the scintillator 30, that is, the first fluorescent composition. It reaches the second sensor panel 332 side where the content ratio of the second fluorescent composition that absorbs more high-energy components of X-rays than the object is relatively high, and is absorbed there. Then, the fluorescence Lb2 corresponding to the absorbed X-rays is generated on the second sensor panel 332 side of the scintillator 30, and the fluorescence Lb2 is detected by the second sensor panel 332. Thereby, image data based on the high energy component of incident X-rays is generated.

  Then, the fluorescence Lb1 toward the second sensor panel and the fluorescence Lb2 toward the first sensor panel are both attenuated by absorption or the like in the scintillator 30 itself. Therefore, in the first sensor panel 331, the fluorescence Lb2 is prevented from being mixed and detected in the fluorescence Lb1, and in the second sensor panel 32, the fluorescence Lb1 is mixed into the fluorescence Lb2 and detected. Is prevented.

The first fluorescent composition and the second fluorescent composition are not limited to the combination of BaFX: Eu and CaWO ₄ described above. As long as the K absorption edge can be distinguished, the fluorescent compositions shown in the table below are used. It can use combining suitably from the inside. For example, when BaFX: Eu is used as the first fluorescent composition, BaSO4: Eu, HfP 2 O 7, YTaO 4, or the like can be used as the second fluorescent composition instead of CaWO ₄ . In the X-ray image detection apparatus 303 of this example, the photoelectric conversion elements 342 and 352 included in the pixels 341 and 351 of the first sensor panel 331 and the second sensor panel 332 are light in the blue wavelength range. Formed in the semiconductor substrates 340 and 350 having the absorption characteristics with respect to the light, and has spectral sensitivity substantially only in the blue wavelength region. In such a case, the first fluorescent composition and the second fluorescent composition As the fluorescent composition, among the fluorescent compositions shown in the table below, it is preferable to use those whose fluorescent wavelength is in the blue wavelength range (200 nm to 495 nm).

  FIG. 8 shows another example of the radiation image detection apparatus for explaining the embodiment of the present invention. Note that elements common to the above-described X-ray image detection apparatuses 3, 103, 203, and 303 are denoted by common reference numerals, and description thereof is omitted or simplified.

  The X-ray image detection apparatus 403 shown in FIG. 8 includes a scintillator 130, and a first sensor panel 431 and a second sensor panel 432 arranged so as to sandwich the scintillator 130 therebetween.

The scintillator 130 is formed of a mixture of the first fluorescent composition and the second fluorescent composition, and europium-activated barium fluorohalide (BaFX: Eu) is used as the second fluorescent composition as the first fluorescent composition. Terbium activated gadolinium oxide (Gd ₂ O ₂ S: Tb) is used as the composition. In this case, the fluorescence peak wavelength (380 nm) emitted from the first fluorescent composition (BaFX: Eu) is in the blue wavelength range, and the fluorescence emitted from the second fluorescent composition (Gd ₂ O ₂ S: Tb). The peak wavelength (545 nm) is in the green wavelength region.

  The first sensor panel 431 includes a semiconductor substrate 340 formed of a semiconductor material having a band gap of 2.8 eV or more, and an array of first pixels 441 provided on the semiconductor substrate 340. Each of the first pixels 441 includes a photoelectric conversion element 242 and a reading circuit portion 343. The photoelectric conversion element 242 is an organic photoelectric conversion element in which a blue absorption OPC film is used as a photoelectric conversion film, has a spectral sensitivity substantially only in the blue wavelength region, and is formed on the semiconductor substrate 340. Yes. The read circuit portion 343 is formed on the semiconductor substrate 340.

  The second sensor panel 432 includes a semiconductor substrate 350 formed of a semiconductor material having a band gap of 2.8 eV or more, and an array of second pixels 451 provided on the semiconductor substrate 350. Each of the second pixels 451 includes a photoelectric conversion element 252 and a reading circuit portion 353. The photoelectric conversion element 252 is an organic photoelectric conversion element in which a green absorption OPC film is used as a photoelectric conversion film, has a spectral sensitivity only in a substantially green wavelength region, and is formed on the semiconductor substrate 350. Yes. The read circuit portion 353 is formed on the semiconductor substrate 350.

  In the X-ray image detection apparatus 403 configured as described above, incident X-rays pass through the first sensor panel 431 and enter the scintillator 130. On the X-ray incident side of the scintillator 130, that is, the first sensor panel 431 side, the content of the first fluorescent composition that mainly absorbs the low energy component of X-rays is relatively high. On the one sensor panel 431 side, low energy components of incident X-rays are mainly absorbed. Then, on the first sensor panel 431 side of the scintillator 130, fluorescence Lb in a blue wavelength region corresponding to the absorbed X-rays is generated, and this fluorescence Lb is detected by the first sensor panel 431. Thereby, image data based on the low energy component of the incident X-ray is generated.

  On the other hand, the high energy component of incident X-rays is not absorbed on the first sensor panel 431 side where the content of the first fluorescent composition is high in the scintillator 130, but is deep in the scintillator 130, that is, the first fluorescent composition. It reaches the second sensor panel 432 side where the content rate of the second fluorescent composition that absorbs more high-energy components of X-rays than the object is relatively high, and is absorbed there. Then, on the second sensor panel 432 side of the scintillator 130, fluorescence Lg in the green wavelength range corresponding to the absorbed X-rays is generated, and this fluorescence Lg is detected by the second sensor panel 432. Thereby, image data based on the high energy component of incident X-rays is generated.

  The organic photoelectric conversion element 242 included in the first pixel 441 of the first sensor panel 431 has spectral sensitivity substantially only in the blue wavelength region, and the second sensor panel 432 has a second sensitivity. The organic photoelectric conversion element 252 included in the pixel 451 has spectral sensitivity substantially only in the green wavelength region. Therefore, the first sensor panel 431 prevents the detection of the fluorescence Lg mixed with the fluorescence Lb, and the second sensor panel 432 detects the detection of the fluorescence Lb mixed with the fluorescence Lg. Is prevented.

  The above-described radiographic image detection apparatus can detect a radiographic image with high sensitivity and high definition, and is therefore required to detect a sharp image with a low radiation dose, such as an X-ray imaging apparatus for medical diagnosis such as mammography. It can be used by incorporating it into various devices. For example, it can be used for nondestructive inspection as an industrial X-ray imaging apparatus, or can be used as a detection apparatus for particle beams (α rays, β rays, γ rays) other than electromagnetic waves, and its application range is wide. .

  Hereinafter, materials that can be used for the TFTs that constitute the readout circuit units 43 and 53 and the insulating substrates 40 and 50 in the X-ray image detection apparatus 3 described above will be described.

[TFT]
As the active layer of the TFT, an inorganic semiconductor material such as amorphous silicon is often used, but an organic material can be used as described in, for example, Japanese Patent Application Laid-Open No. 2009-212389. The organic TFT may have any type of structure, but the most preferred is a field effect transistor (FET) structure. In this FET structure, a gate electrode is provided on a part of the upper surface of an insulating substrate, and further, an insulating layer is provided so as to cover the electrode and to be in contact with the substrate at a portion other than the electrode. Further, a semiconductor active layer is provided on the upper surface of the insulator layer, and the transparent source electrode and the transparent drain electrode are separately arranged on a part of the upper surface. Although this configuration is called a top contact type element, a bottom contact type element in which a source electrode and a drain electrode are located below the semiconductor active layer can also be preferably used. Alternatively, a vertical transistor structure in which carriers flow in the film thickness direction of the organic semiconductor film may be used.

(Active layer)
The organic semiconductor material referred to here is an organic material exhibiting the characteristics of a semiconductor, and similarly to a semiconductor made of an inorganic material, a p-type organic semiconductor material that conducts holes as carriers (or simply p-type). And an n-type organic semiconductor material that conducts electrons as carriers (or simply referred to as an n-type material or an electron transport material). In general, many organic semiconductor materials exhibit better characteristics than p-type materials, and generally, p-type transistors are also superior in terms of transistor operation stability in the atmosphere. The material will be described.

One of the characteristics of the organic thin film transistor is carrier mobility (also simply referred to as mobility) μ indicating the mobility of carriers in the organic semiconductor layer. Although it depends on the application, in general, the mobility should be high, preferably 1.0 × 10 ⁻⁷ cm ² / Vs or more, and more preferably 1.0 × 10 ⁻⁶ cm ² / Vs or more. Preferably, it is 1.0 × 10 ⁻⁵ cm ² / Vs or more. The mobility can be obtained by characteristics when a field effect transistor (FET) element is manufactured or by a time-of-flight measurement (TOF) method.

  The p-type organic semiconductor material may be a low molecular material or a high molecular material, but is preferably a low molecular material. Low molecular weight materials can be easily purified because various purification methods such as sublimation purification, recrystallization, column chromatography, etc. can be applied. Many have high characteristics for reasons such as these. The molecular weight of the low molecular weight material is preferably 100 or more and 5000 or less, more preferably 150 or more and 3000 or less, and still more preferably 200 or more and 2000 or less.

  As such a p-type organic semiconductor material, a phthalocyanine compound or a naphthalocyanine compound can be exemplified, and specific examples are shown below. M represents a metal atom, Bu represents a butyl group, Pr represents a propyl group, Et represents an ethyl group, and Ph represents a phenyl group.

(Constituent elements of switch elements other than the active layer)
The material constituting the gate electrode, the source electrode, or the drain electrode is not particularly limited as long as it has necessary conductivity. For example, ITO (indium doped tin oxide), IZO (indium doped zinc oxide), Transparent conductive oxides such as SnO ₂ , ATO (antimony-doped tin oxide), ZnO, AZO (aluminum-doped zinc oxide), GZO (gallium-doped zinc oxide), TiO ₂ , FTO (fluorine-doped tin oxide), PEDOT / PSS Examples thereof include transparent conductive polymers such as (poly (3,4-ethylenedioxythiophene) / polystyrene sulfonic acid) and carbon materials such as carbon nanotubes. These electrode materials can be formed by a method such as a vacuum deposition method, a sputtering method, or a solution coating method.

The material used for the insulating layer is not particularly limited as long as it has a necessary insulating effect. For example, inorganic materials such as silicon dioxide, silicon nitride, and alumina, polyester (PEN (polyethylene naphthalate), PET ( Polyethylene terephthalate)), polycarbonate, polyimide, polyamide, polyacrylate, epoxy resin, polyparaxylylene resin, novolac resin, PVA (polyvinyl alcohol), PS (polystyrene), and the like. These insulating film materials can be formed by a method such as vacuum deposition, sputtering, or solution coating.
For other configurations related to the organic TFT described above, for example, the description in JP-A-2009-212389 is helpful.

  In addition, an amorphous oxide described in, for example, Japanese Patent Application Laid-Open No. 2010-186860 can also be used for the active layer of the TFT. Here, an active layer containing an amorphous oxide included in a field effect transistor described in Japanese Patent Application Laid-Open No. 2010-186860 will be described. This active layer functions as a channel layer of a field effect transistor in which electrons or holes move.

  The active layer is configured to include an amorphous oxide semiconductor. Since the amorphous oxide semiconductor can be formed at a low temperature, it is preferably formed over a flexible substrate. The amorphous oxide semiconductor used for the active layer is preferably an amorphous oxide containing at least one element selected from the group consisting of In, Sn, Zn, or Cd, more preferably In. An amorphous oxide containing at least one selected from the group consisting of Sn and Zn, more preferably an amorphous oxide containing at least one selected from the group consisting of In and Zn.

Specific examples of the amorphous oxide used for the active layer include In ₂ O ₃ , ZnO, SnO ₂ , CdO, Indium-Zinc-Oxide (IZO), Indium-Tin-Oxide (ITO), Gallium- Zinc-Oxide (GZO), Indium-Gallium-Oxide (IGO), and Indium-Gallium-Zinc-Oxide (IGZO) are mentioned.

  As a method for forming the active layer, it is preferable to use a vapor phase film forming method with a polycrystalline sintered body of an oxide semiconductor as a target. Among vapor deposition methods, sputtering and pulsed laser deposition (PLD) are suitable. Furthermore, the sputtering method is preferable from the viewpoint of mass productivity. For example, the film is formed by controlling the degree of vacuum and the oxygen flow rate by RF magnetron sputtering deposition.

  The formed active layer is confirmed to be an amorphous film by a well-known X-ray diffraction method. The composition ratio of the active layer is determined by RBS (Rutherford backscattering) analysis.

The electrical conductivity of the active layer is preferably 10 ⁻⁴ Scm ⁻¹ or more and less than 10 ² Scm ⁻¹ , more preferably 10 ⁻¹ Scm ⁻¹ or more and less than 10 ² Scm ⁻¹ . Examples of the method for adjusting the electrical conductivity of the active layer include a known adjustment method using oxygen vacancies, an adjustment method using a composition ratio, an adjustment method using impurities, and an adjustment method using an oxide semiconductor material.
For other configurations relating to the above-described amorphous oxide, for example, the description in Japanese Patent Application Laid-Open No. 2010-186860 is helpful.

[Insulating substrate]
Examples of the insulating substrate include glass, quartz, and plastic film. Examples of plastic films include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), and cellulose triacetate. Examples thereof include films made of (TAC), cellulose acetate propionate (CAP) and the like. Further, these plastic films may contain an organic or inorganic filler. In addition, a flexible substrate formed using aramid, bionanofiber, or the like that is flexible, has low thermal expansion, and high strength, and has characteristics that cannot be obtained with existing glass or plastic, can be suitably used.

(Aramid)
The aramid material has high heat resistance with a glass transition temperature of 315 ° C., high rigidity with Young's modulus of 10 GPa, and high dimensional stability with a thermal expansion coefficient of −3 to 5 ppm / ° C. For this reason, when an aramid film is used, it is possible to easily form a high-quality film of a semiconductor layer as compared with a case where a general resin film is used. In addition, the high heat resistance of the aramid material allows the electrode material to be cured at a high temperature to reduce resistance. Furthermore, it can cope with automatic mounting of IC including a solder reflow process. Furthermore, since the thermal expansion coefficient is close to that of ITO (indium tin oxide), gas / barrier film, and glass substrate, there is little warpage after production. And hard to break. Here, it is preferable to use an aramid material that does not contain halogen and is halogen-free (conforming to JPCA-ES01-2003). The aramid film may be laminated with a glass substrate or a PET substrate, or may be attached to a device casing.

  Suitable for aramid materials that can be easily formed into colorless and transparent films by solving low solubility in solvents due to the high cohesion (hydrogen bonding) between molecules of aramid by molecular design. Can be used. The molecular design that controls the order of the monomer units and the type and position of the substituents on the aromatic ring maintains the linear molecular structure with high linearity that leads to high rigidity and dimensional stability of the aramid material, while maintaining solubility. Good moldability is obtained. This molecular design can also be halogen-free.

  Moreover, it can use suitably also about the aramid material in which the characteristic of the in-plane direction of the film was optimized. By controlling the tension condition for each step of solution casting, longitudinal stretching, and transverse stretching according to the strength of the aramid film that changes sequentially during molding, it has a highly linear rod-like molecular structure and anisotropy in physical properties. The in-plane characteristics of the aramid film that tends to occur can be balanced.

  Specifically, in the solution casting process, the physical properties in the in-plane thickness direction are controlled by controlling the drying rate of the solvent, and the strength of the film containing the solvent and the peel strength from the cast drum are optimized. . In the longitudinal stretching step, stretching conditions according to the strength of the film, which changes sequentially during stretching, and the residual amount of solvent are precisely controlled. In the transverse stretching step, the transverse stretching conditions are controlled in accordance with changes in the film strength that change due to heating, and the transverse stretching conditions for relaxing the residual stress of the film are controlled. Use of such an aramid material can solve the problem that the aramid film after molding is curled.

  In any of the above devices for ease of forming and the device for balancing the characteristics in the in-plane direction of the film, since the rod-like molecular structure with high linearity unique to aramid is maintained, the thermal expansion coefficient can be kept low. It is also possible to further reduce the thermal expansion coefficient by changing the stretching conditions during film formation.

(Bionanofiber)
A nanofiber can be used as a reinforcement of a transparent and flexible resin material because a component sufficiently small with respect to the wavelength of light does not cause light scattering. Among nanofibers, cellulose microfibril bundles produced by bacteria (Acetobacter Xylinum) have a width of 50 nm and a size of about 1/10 of the visible light wavelength, and have high strength, high elasticity, and low heat. It has a characteristic of being swollen, and a composite material of this bacterial cellulose and a transparent resin (sometimes referred to as bionanofiber) can be suitably used.

Transparent Bionano that shows light transmittance of about 90% at a wavelength of 500 nm while impregnating and curing transparent resin such as acrylic resin and epoxy resin on bacterial cellulose sheet and containing fiber at a high ratio of about 60-70% Fiber is obtained. This bionanofiber provides a low thermal expansion coefficient (about 3 to 7 ppm) comparable to that of silicon crystals, steel-like strength (about 460 MPa), and high elasticity (about 30 GPa).
For the configuration relating to the above-described bio-nanofiber, for example, the description in JP-A-2008-34556 is helpful.

  As described above, the present specification discloses the following radiation image detection devices (1) to (13) and the following radiation imaging device (14).

(1) A first fluorescent composition that mainly absorbs a low energy component of irradiated radiation and emits first fluorescence, and a second that mainly absorbs a high energy component of the radiation and emits second fluorescence. A phosphor having a phosphor composition; a first sensor panel having a first pixel array for detecting the first fluorescence; and disposed on a radiation incident side of the phosphor; And a second sensor panel disposed opposite to the first sensor panel with the phosphor interposed therebetween, wherein the phosphor in the phosphor includes the second pixel array. The content ratio of the first fluorescent composition and the second fluorescent composition is higher in the first fluorescent composition on the first sensor panel side and in the second sensor panel side. A radiological image detection apparatus having a high fluorescent composition.
(2) The radiological image detection apparatus according to (1), wherein the peak wavelength of the first fluorescence is in a first wavelength range, and the peak wavelength of the second fluorescence is in the first wavelength range. The radiographic image detection apparatus in the 2nd wavelength range which remove | deviates from.
(3) In the radiological image detection apparatus according to (2), light in the second wavelength band is selectively blocked between the phosphor and the first sensor panel, and the first A radiation image detection apparatus including a filter that transmits light in a wavelength region.
(4) The radiological image detection apparatus according to (2) or (3), wherein light in the first wavelength range is selectively blocked between a phosphor and the second sensor panel. A radiation image detection apparatus comprising a filter that transmits light in the second wavelength range.
(5) The radiological image detection apparatus according to (3) or (4), wherein the filter is a dichroic filter.
(6) In the radiological image detection apparatus according to (2), a peak wavelength of spectral sensitivity of the first pixel is in the first wavelength range, and a peak wavelength of spectral sensitivity of the second pixel is The radiation image detection apparatus in the second wavelength range.
(7) In the radiological image detection apparatus according to any one of (1) to (6), the first sensor panel includes a semiconductor substrate on which the first array of pixels is provided. The first pixel includes a photoelectric conversion element and a readout circuit unit that reads out charges generated in the photoelectric conversion element, and the readout circuit unit is formed on the semiconductor substrate.
(8) The radiological image detection apparatus according to (7), wherein the semiconductor material forming the semiconductor substrate has a larger band gap than single crystal Si.
(9) The radiological image detection apparatus according to (8), wherein the semiconductor material is any one selected from the group consisting of SiC, GaN, ZnO, C (diamond), BN, and AlN. .
(10) In the radiological image detection apparatus according to (8) or (9), the photoelectric conversion element of the first pixel is formed on the semiconductor substrate, and the first wavelength range is blue. Radiation image detection device in the wavelength range of.
(11) The radiological image detection apparatus according to any one of (1) to (9), wherein the first pixel includes an organic photoelectric conversion element.
(12) The radiological image detection apparatus according to any one of (1) to (11), wherein the first fluorescent composition is BaFX: Eu (where X is halogen), and the second fluorescent composition _things, Gd ₂ O 2 S: radiation image detecting apparatus is Tb.
(13) The radiation image detection apparatus according to (1), wherein the first fluorescent composition is BaFX: Eu (X is halogen), and the second fluorescent composition is CaWO ₄ Image detection device.
(14) The radiographic image detection device according to any one of (1) to (13), the first image data generated by the first sensor panel, and the first image data generated by the second sensor panel. A radiation imaging apparatus comprising: an image processing unit that generates an energy subtraction image using the image data of 2.

DESCRIPTION OF SYMBOLS 1 X-ray imaging apparatus 2 X-ray source 3 X-ray image detection apparatus 4 Console 5 X-ray source holding | maintenance apparatus 6 Stand 10 X-ray source control part 11 High voltage generator 12 X-ray tube 13 Collimator 14 Collimator unit 15 Ceiling rail 16 Car Unit 17 Supporting unit 18 Main body 19 Holding unit 20 Control device 21 Input device 22 Image processing unit 23 Image storage unit 24 Monitor 25 I / F
26 Bus 30 Scintillator (phosphor)
31 First Sensor Panel 32 Second Sensor Panel 40 Insulating Substrate 41 First Pixel 42 Photoelectric Conversion Element 43 Readout Circuit Unit 50 Insulating Substrate 51 Second Pixel 52 Photoelectric Conversion Element 53 Readout Circuit Unit

Claims (14)

A first fluorescent composition that mainly absorbs a low energy component of irradiated radiation and emits first fluorescence, and a second fluorescent composition that mainly absorbs a high energy component of the radiation and emits second fluorescence. A phosphor comprising:
A first sensor panel having a first pixel array for detecting the first fluorescence and disposed on a radiation incident side of the phosphor;
A second sensor panel having a second pixel array for detecting the second fluorescence, and disposed opposite to the first sensor panel with the phosphor interposed therebetween;
With
The content of the first fluorescent composition and the second fluorescent composition in the phosphor is higher on the first sensor panel side than on the first sensor panel side, and on the second sensor panel side. Then, the radiographic image detection apparatus with said 2nd fluorescent composition high. The radiological image detection apparatus according to claim 1,
The peak wavelength of the first fluorescence is in the first wavelength range;
The peak image wavelength of the second fluorescence is a radiological image detection apparatus in a second wavelength region that is out of the first wavelength region. The radiological image detection apparatus according to claim 2,
A radiological image detection apparatus comprising: a filter that selectively blocks light in the second wavelength range and transmits light in the first wavelength range between the phosphor and the first sensor panel. The radiological image detection apparatus according to claim 2 or 3,
A radiation image detection apparatus comprising: a filter that selectively blocks light in the first wavelength range and transmits light in the second wavelength range between a phosphor and the second sensor panel. The radiological image detection apparatus according to claim 3 or 4,
The radiographic image detection apparatus, wherein the filter is a dichroic filter. The radiological image detection apparatus according to claim 2,
The peak wavelength of the spectral sensitivity of the first pixel is in the first wavelength range,
The peak image wavelength of the spectral sensitivity of the second pixel is a radiological image detection apparatus in the second wavelength range. The radiological image detection apparatus according to any one of claims 1 to 6,
The first sensor panel has a semiconductor substrate on which the first array of pixels is provided,
The first pixel includes a photoelectric conversion element and a readout circuit unit that reads out charges generated in the photoelectric conversion element, and the readout circuit unit is formed on the semiconductor substrate. The radiological image detection apparatus according to claim 7,
The semiconductor material which forms the said semiconductor substrate is a radiographic image detection apparatus with a larger band gap than single crystal Si. The radiological image detection apparatus according to claim 8,
The radiographic image detection apparatus, wherein the semiconductor material is any one selected from the group consisting of SiC, GaN, ZnO, C (diamond), BN, and AlN. The radiological image detection apparatus according to claim 8 or 9,
The photoelectric conversion element of the first pixel is formed on the semiconductor substrate;
The first wavelength range is a radiological image detection apparatus that is a blue wavelength range. The radiological image detection apparatus according to any one of claims 1 to 9,
The first pixel is a radiation image detection apparatus including an organic photoelectric conversion element. It is a radiographic image detection apparatus as described in any one of Claim 1 to 11, Comprising:
The first fluorescent composition is BaFX: Eu (X is halogen),
The second fluorescent composition is a radiological image detection apparatus in which Gd ₂ O ₂ S: Tb is used. The radiological image detection apparatus according to claim 1,
The first fluorescent composition is BaFX: Eu (X is halogen),
Said second fluorescent composition, the radiation image detection apparatus is CaWO _4. The radiological image detection apparatus according to any one of claims 1 to 13,
An image processing unit that generates an energy subtraction image using the first image data generated by the first sensor panel and the second image data generated by the second sensor panel;
A radiographic apparatus comprising:

Images