JP5504203B2 - Radiation conversion panel - Google Patents

Description

  The present invention relates to a radiation conversion panel that converts radiation into visible light and receives the light.

  In the medical field, a radiation imaging apparatus is used that images a human body by irradiating the human body with radiation and detecting the intensity of the radiation transmitted through the human body. In a radiation imaging apparatus, a direct conversion type radiation conversion panel that converts radiation directly into an electrical signal, an indirect conversion type radiation conversion panel that converts radiation into visible light, and converts the converted visible light into an electrical signal; There is.

  In an indirect conversion type radiation conversion panel, a scintillator is attached to a photoelectric conversion layer provided with a photoelectric conversion element with an adhesive or the like to prevent ingress of dust, and is formed between the photoelectric conversion layer and the scintillator. The image quality is improved by reducing the light refraction caused by the air gap.

  However, the thermal expansion coefficient of the optical coupler (epoxy resin for sealing an optical semiconductor) used as an adhesive is 200 PPM / ° C., which is about 30 times or more the thermal expansion coefficient of the scintillator and the photoelectric conversion element. Since the difference in expansion coefficient between the adhesive, the scintillator, and the photoelectric conversion element is large, the optical coupler is peeled off due to the temperature change, and the scintillator and the photoelectric conversion layer are separated.

  In order to solve such a problem, Patent Document 1 shown below describes that a scintillator is mixed in an optical coupler layer to lower the thermal expansion coefficient of the optical coupler layer and prevent peeling. .

JP 2001-188085 A

  However, although the technique of Patent Document 1 described above can suppress the peeling of the optical coupler layer, since the scintillator and the photoelectric conversion layer are bonded using an optical coupler, the scintillator and the photoelectric conversion layer are bonded together. However, there is a possibility that the image quality of the radiographic image is deteriorated due to the peeling. Further, the adhesive is deteriorated and colored by radiation, and the image quality of the radiation image is deteriorated by coloring of the adhesive.

  Therefore, the present invention has been made in view of such conventional problems, and an object of the present invention is to provide a radiation conversion panel that prevents deterioration of the image quality of a radiation image.

  To achieve the above object, the present invention provides a radiation conversion panel, a support substrate that also functions as a scintillator having sensitivity to radiation in which a phosphor is kneaded, and the support substrate formed on the support substrate, A first photoelectric conversion element having sensitivity to fluorescence emitted from the phosphor, and a first switching element for outputting a signal of the first photoelectric conversion element.

  The first photoelectric conversion element and the first switching element may be formed in contact with the support substrate.

  The first photoelectric conversion element may be formed in contact with the support substrate, and the first switching element may be formed on the support substrate with the first photoelectric conversion element interposed therebetween.

  The side of the support substrate on which the first photoelectric conversion element and the first switching element are provided has a larger size of the incorporated phosphor particles than the side on which the first photoelectric conversion element is not provided. At least one of the following conditions may be satisfied: the density of the kneaded phosphor particles is high, and the amount of the kneaded activator is large.

  The first photoelectric conversion element may be formed using an organic photoelectric conversion material.

  On the side of the support substrate where the first photoelectric conversion element and the first switching element are not provided, a second photoelectric conversion element having sensitivity to fluorescence emitted by the phosphor, and a second photoelectric conversion element A second switching element for outputting a signal may be formed.

  Of the first photoelectric conversion element and the second photoelectric conversion element, at least the photoelectric conversion element provided on the side irradiated with radiation may be molded using an organic photoelectric conversion material.

  Of the first photoelectric conversion element and the second photoelectric conversion element, the photoelectric conversion element provided on the side opposite to the irradiation side may be molded using an inorganic photoelectric conversion material.

  At least one of the first switching element and the second switching element may be formed using an oxide semiconductor.

  The support substrate may include aramid or bionanofiber.

  According to the present invention, since the phosphor is kneaded into the support substrate to function as a scintillator, it is not necessary to attach the scintillator using an adhesive on the first photoelectric conversion element, and the scintillator and the first photoelectric conversion element It is possible to prevent deterioration of the image quality of the radiation image due to peeling. In addition, since the process of manufacturing the scintillator separately from the support substrate and the process of attaching the scintillator are eliminated, the cost is reduced. Moreover, since no adhesive is used, the image quality of the radiation image is not deteriorated by the adhesive.

  Since the phosphor is farther away from the first photoelectric conversion element, the particles are made smaller, so that the range of fluorescence when reaching the first photoelectric conversion element can be narrowed and blurring of the radiographic image to be captured is suppressed. And the image quality of the radiation image can be improved.

  Since the phosphor located farther from the first photoelectric conversion element has a lower density, the phosphor located farther from the first photoelectric conversion element has a smaller amount of emitted fluorescence, and blurs the captured radiation image. The image quality of the radiation image can be improved.

  Since the amount of the activator decreases as the phosphor is located farther from the first photoelectric conversion element, the amount of fluorescence emitted from the phosphor farther from the first photoelectric conversion element becomes smaller and the image is captured. The blur of the radiation image can be suppressed, and the image quality of the radiation image can be improved.

  In order to output the signals of the second photoelectric conversion element and the second photoelectric conversion element sensitive to the fluorescence emitted by the phosphor on the side of the support substrate where the first photoelectric conversion element and the first switching element are not provided. Since the second switching element is formed, two radiation images can be obtained simultaneously.

  Of the first photoelectric conversion element and the second photoelectric conversion element, at least the photoelectric conversion element provided on the side irradiated with radiation is molded using an organic photoelectric conversion material. The light can enter the support substrate that functions as a scintillator without being attenuated.

  Since at least one of the first switching element and the second switching element is formed using an oxide semiconductor, the switching element can be formed without deforming the support substrate by heat.

  Since the support substrate contains aramid or bionanofiber, the heat resistance of the support substrate can be improved and the coefficient of thermal expansion can be lowered.

It is a block diagram of the radiation imaging system of this Embodiment. It is a perspective view of the electronic cassette shown in FIG. It is a figure which shows typically the electrical connection between the arrangement | sequence of the photoelectric conversion element in a radiation conversion panel, and a photoelectric conversion element and a cassette control part. It is a figure which shows the circuit structure of the electronic cassette shown in FIG. It is the figure which showed typically an example of the cross section of the radiation conversion panel shown in FIG.3 and FIG.4. It is the figure which showed typically the other example of the cross section of the radiation conversion panel shown in FIG. It is the figure which showed typically the other example of the cross section of the radiation conversion panel shown in FIG.3 and FIG.4. It is the figure which showed typically an example of the cross section of the radiation conversion panel of the modification 1. FIG. It is the figure which showed typically the other example of the cross section of the radiation conversion panel of the modification 1. It is a perspective view of the electronic cassette by which the panel part and control part of the modification 2 were laminated | stacked. FIG. 11A is a perspective view illustrating a state of an electronic cassette in which the panel unit and the control unit are joined by a hinge during conveyance of the second modification, and FIG. 11B illustrates the state of FIG. 11A in order to use the electronic cassette. FIG. 11C is a perspective view showing a state of the electronic cassette when in use.

  The radiation conversion panel according to the present invention will be described in detail below with reference to the accompanying drawings with preferred embodiments.

  FIG. 1 is a configuration diagram of a radiation imaging system according to an embodiment. The radiation imaging system 10 includes a radiation source 18 for irradiating a patient 16 as a subject 14 lying on an imaging stand 12 such as a bed with radiation 16 having a dose according to imaging conditions, and radiation 16 transmitted through the subject 14. An electronic cassette (radiation imaging device) 20 that detects and converts to a radiographic image, a console 24 that controls the radiation source 18 and the electronic cassette 20, and a display device 26 that displays the radiographic image are provided.

  Between the console 24, the radiation source 18, the electronic cassette 20, and the display device 26, for example, UWB (Ultra Wide Band), IEEE802.11. Signals are transmitted and received by wireless LAN using a / g / n or wireless communication using millimeter waves or the like. Note that signals may be transmitted and received by wired communication using a cable.

  Connected to the console 24 is an RIS (radiology department information system) 28 that centrally manages radiographic images and other information handled in the radiology department in the hospital. A HIS (medical information system) 30 to be managed is connected.

  FIG. 2 is a perspective view of the electronic cassette 20 shown in FIG. 1, and the electronic cassette 20 includes a panel unit 32 and a control unit 34 disposed on the panel unit 32. The thickness of the panel unit 32 is set to be thinner than the thickness of the control unit 34.

  The panel unit 32 includes a substantially rectangular casing 40 made of a material that can transmit the radiation 16, and the imaging surface 42 of the panel unit 32 is irradiated with the radiation 16. A guide line 44 indicating the imaging area and imaging position of the subject 14 is formed at a substantially central portion of the imaging surface 42. The outer frame of the guide line 44 becomes an imageable region 36 indicating the irradiation field of the radiation 16. The center position of the guide line 44 (intersection where the guide line 44 intersects in a cross shape) is the center position of the imageable area 36 and the geometric center position of the electronic cassette 20.

  The control unit 34 has a substantially rectangular casing 50 made of a material that is impermeable to the radiation 16. The housing 50 extends along one end of the imaging surface 42, and the control unit 34 is disposed outside the imageable region 36 on the imaging surface 42. In this case, inside the housing 50, there is a cassette control unit 80 that controls a panel unit 32, which will be described later, a power supply unit 108 such as a battery, and a communication unit 110 that can transmit and receive signals wirelessly between the console 24. Etc. are arranged (see FIGS. 3 and 4). The power supply unit 108 supplies power to the panel unit 32, and also supplies power to the cassette control unit 80 and the communication unit 110.

  On the side surface 52 in the short direction of the control unit 34, as an interface means capable of transmitting and receiving information between the input terminal 54 of the AC adapter for charging the power source unit 108 from an external power source and an external device. USB terminal 56 and a card slot 58 for loading a memory card such as a PC card.

  The panel unit 32 includes a radiation conversion panel and a drive circuit unit which will be described later. The radiation conversion panel is an indirect conversion type in which the radiation 16 transmitted through the subject 14 is once converted into fluorescence contained in a visible light region by a scintillator (light conversion unit), and the converted fluorescence is converted into an electric signal by a photoelectric conversion element. It is a radiation conversion panel.

  FIG. 3 is a diagram schematically showing the arrangement of photoelectric conversion elements in the radiation conversion panel and the electrical connection between the photoelectric conversion elements and the cassette control unit. In the radiation conversion panel 70, a large number of photoelectric conversion elements (first photoelectric conversion elements) 72 are arranged on a substrate (not shown), and a plurality of photoelectric conversion elements 72 for supplying control signals from the drive circuit unit 74 to the photoelectric conversion elements 72. The gate lines 76 and a plurality of signal lines 78 for reading out electrical signals output from the plurality of photoelectric conversion elements 72 and outputting the signals to the drive circuit unit 74 are arranged. The cassette control unit 80 of the control unit 34 controls the drive circuit unit 74 by supplying a control signal to the drive circuit unit 74.

  FIG. 4 is a diagram illustrating a circuit configuration of the electronic cassette. The radiation conversion panel 70 includes photoelectric conversion elements 72 and TFTs 82 arranged in a matrix. The photoelectric conversion layer in which each photoelectric conversion element 72 that converts visible light into an electric signal is formed may be arranged on an array of matrix-like TFTs 82. In each photoelectric conversion element 72 to which a bias voltage is supplied from the bias circuit 84 constituting the drive circuit unit 74, charges generated by converting visible light into an electric signal (analog signal) are accumulated, and the TFT 82 is provided for each column. The charge can be read out as an image signal by sequentially turning on the. That is, the TFT 82 is a switching element for outputting a signal from the photoelectric conversion element 72.

  A TFT (first switching element) 82 connected to each photoelectric conversion element 72 is connected to a gate line 76 extending in parallel to the column direction and a signal line 78 extending in parallel to the row direction. Each gate line 76 is connected to a gate drive circuit 86, and each signal line 78 is connected to a multiplexer 92 constituting the drive circuit unit 74. A control signal for controlling on / off of the TFTs 82 arranged in the column direction is supplied from the gate drive circuit 86 to the gate line 76. In this case, the gate drive circuit 86 is supplied with an address signal from the cassette control unit 80, and the gate drive circuit 86 performs on / off control of the TFT 82 in accordance with the address signal.

  When the TFT 82 is turned on, the current held in each photoelectric conversion element 72 flows out to the signal line 78 via the TFTs 82 arranged in the row direction. This charge is amplified by the amplifier 88. A multiplexer 92 is connected to the amplifier 88 via a sample and hold circuit 90. The multiplexer 92 includes an FET switch 94 that switches a signal line 78 that outputs a signal, and a multiplexer driving circuit 96 that turns on one FET switch 94 and outputs a selection signal. The multiplexer drive circuit 96 is supplied with an address signal from the cassette control unit 80, and turns on one FET switch 94 in accordance with the address signal. An A / D converter 98 is connected to the FET switch 94, and a radiation image converted into a digital signal by the A / D converter 98 is supplied to the cassette control unit 80 via the flexible substrate 112. The flexible substrate 112 electrically connects the cassette control unit 80 and the drive circuit unit 74.

  The TFT 82 functioning as a switching element may be realized in combination with another imaging element such as a CMOS (Complementary Metal-Oxide Semiconductor) image sensor. Furthermore, it can be replaced with a CCD (Charge-Coupled Device) image sensor that transfers charges while shifting them with a shift pulse corresponding to a gate signal referred to as a TFT.

  The cassette control unit 80 includes an address signal generation unit 100 that generates an address signal to be supplied to the gate drive circuit 86 and the multiplexer drive circuit 96, and an image memory 102 that stores a radiation image detected by the radiation conversion panel 70. Prepare. The radiographic image stored in the image memory 102 is transmitted to the console 24 or the like by the communication unit 110.

  FIG. 5 is a diagram schematically showing an example of a cross section of the radiation conversion panel shown in FIGS. 3 and 4. The radiation conversion panel 70 includes a support substrate 120 and photoelectric conversion elements 72 and TFTs 82 formed on the support substrate 120 by vapor deposition or the like. The photoelectric conversion element 72 and the TFT 82 are formed in contact with the support substrate 120. In FIG. 5, the photoelectric conversion element 72 and the TFT 82 are represented by one layer. However, as illustrated in FIG. 6, the photoelectric conversion element 72 and the TFT 82 may be formed of two layers. Specifically, the layer of the photoelectric conversion element 72 may be formed on the support substrate 120, and the TFT 82 may be formed thereon. That is, the layer of the TFT 82 may be formed on the support substrate 120 with the photoelectric conversion element 72 interposed therebetween. The support substrate 120 is a flexible substrate containing plastic or the like. Specifically, polyesters such as polyethylene terephthalate, polybutylene phthalate, and polyethylene naphthalate, polyethylene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, poly (chlorotrifluoroethylene), etc. may be included. A flexible substrate (flexible substrate) can be used. The support substrate 120 may be a flexible substrate including aramid, bionanofiber, or the like. Aramid and bionanofiber are materials that have both high heat resistance and low expansion coefficient. Polyethylene terephthalate absorbs radiation and emits light having a peak at 370 nm.

  The support substrate 120 is kneaded with a phosphor 122 that absorbs radiation and emits fluorescence. That is, the support substrate 120 kneaded with the scintillator functions as a scintillator that converts incident radiation into fluorescence in a wavelength band in which the photoelectric conversion element 72 has sensitivity. Thereby, the support substrate 120 functions as a scintillator having sensitivity to radiation. The wavelength band of the fluorescence emitted by the phosphor 122 is preferably in the visible light band (about 360 nm to 830 nm). In order to enable monochrome imaging by the photoelectric conversion element 72, the wavelength band of green is included. Preferably it is.

Specific examples of the phosphor 122 include those containing gadolinium sulfate (GOS), La ₂ O ₂ S: Tb, BaFX: Eu, BaSO ₄ : Pb, CaWO ₄ , La ₂ OBr: Tb, ZnS: Ag. May be included.

  The photoelectric conversion element 72 may be formed using an organic photoelectric conversion material (OPC; Organic Photoconductor), absorbs the fluorescence emitted by the phosphor, and generates a charge corresponding to the received light. In the case of the photoelectric conversion element 72 formed using an organic photoelectric conversion material, the photoelectric conversion element 72 hardly absorbs electromagnetic waves other than the fluorescence having a sharp absorption spectrum in visible light and emitted from the phosphor 122. In addition, noise generated by absorption of radiation such as X-rays by the photoelectric conversion element 72 can be effectively suppressed. In addition, since an organic photoelectric conversion material is formed with a vacuum evaporation method, it is hard to peel compared with bonding, such as adhesion.

  The organic photoelectric conversion material constituting the photoelectric conversion element 72 is preferably as close as possible to the absorption peak wavelength of the phosphor and the emission peak wavelength of the phosphor in order to best absorb the fluorescence emitted by the phosphor. Ideally, the absorption peak wavelength of the organic photoelectric conversion material coincides with the emission peak wavelength of the phosphor 122. However, the smaller the difference between the two, the more the photoelectric conversion element 72 emits fluorescence emitted from the phosphor 122. 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 phosphor 122 is preferably within 10 nm, and more preferably within 5 nm. Note that the organic photoelectric conversion material may be applied to the support substrate 120. Also in this case, the adhesion is good.

  Note that the photoelectric conversion element 72 may be formed using an inorganic photoelectric conversion material. Since the inorganic photoelectric conversion material has low selectivity depending on the wavelength of light, a filter that transmits visible light may be provided in the photoelectric conversion element 72. Thereby, the photoelectric conversion element 72 can have the function equivalent to an organic photoelectric conversion material by absorbing the light which permeate | transmitted this filter. Inorganic photoelectric conversion materials include amorphous silicon (a-Si).

The TFT 82 is formed using, for example, an oxide semiconductor. An amorphous oxide semiconductor (IGZO) may be used as the oxide semiconductor. Since IGZO (InGaZnO ₄ ) can be molded at a low temperature, the TFT 82 can be molded without deforming the support substrate 120 by heat even when a flexible support substrate 120 such as plastic is used. Note that when the support substrate 120 is formed using aramid or bionanofiber, the TFT 82 may be formed using a semiconductor other than an oxide semiconductor. This is because aramid and bionanofiber have high heat resistance, so that the support substrate 120 is not easily deformed even when the TFT 82 is formed at a high temperature.

  In this manner, the phosphor 122 is kneaded into the support substrate 120 so that the support substrate 120 functions as a scintillator, so that the scintillator is attached to the photoelectric conversion element 72 provided on the support substrate 120 with an adhesive. This eliminates the need to prevent deterioration of the image quality of the radiation image due to peeling between the scintillator and the photoelectric conversion element 72. Further, since the process of manufacturing the scintillator separately from the support substrate 120 and the process of attaching the scintillator are eliminated, the cost is reduced. Moreover, since no adhesive is used, the image quality of the radiation image is not deteriorated by the adhesive.

  FIG. 7 is a diagram schematically showing another example of the cross section of the radiation conversion panel shown in FIGS. 3 and 4, and only the parts different from FIG. 5 will be described. The support substrate 120 shown in FIG. 7 differs from the support substrate 120 shown in FIG. 5 in that the size (size) and density of the particles of the phosphor 122 kneaded are different depending on the location.

  As shown in FIG. 7, the particles of the phosphor 122 on the side of the support substrate 120 where the photoelectric conversion elements 72 and TFTs 82 are provided are the phosphors on the side of the support substrate 120 where the photoelectric conversion elements 72 and TFTs 82 are not provided. Greater than 122 particles.

  When the particles of the phosphor 122 are large, the amount of emitted fluorescence increases, so the luminance signal output from the photoelectric conversion element 72 increases, but the emitted fluorescence easily diffuses (of the emitted light). Since the spread range is widened), the obtained radiation image is easily blurred. In addition, when the phosphor 122 particles are small, the emitted fluorescence is difficult to diffuse (because the spread range of the emitted light becomes narrow), so that a clear radiation image can be obtained, but the amount of emitted fluorescence is small. Therefore, the luminance signal output from the photoelectric conversion element 72 becomes small.

  As shown in FIG. 7, the particles of the phosphor 122 kneaded on the side of the support substrate 120 where the photoelectric conversion element 72 and the TFT 82 are provided are provided with the photoelectric conversion element 72 and the TFT 82 of the support substrate 120. The density is higher than the phosphor 122 on the non-side. The higher the density of the phosphor particles, the greater the amount of fluorescence emitted.

  Reference numeral 124 represents an interface, and the particle size and particle density of the phosphor 122 differ from each other at the interface 124. Thus, the particle size and particle density of the phosphor 122 are changed stepwise. Note that the interface 124 is at the particle size of the phosphor, and the support substrate 120 has no interface. That is, there is one support substrate 120.

  Further, the activator of the phosphor 122 on the side where the photoelectric conversion element 72 and the TFT 82 of the support substrate 120 are provided is used as the activator of the phosphor 122 on the side of the support substrate 120 where the photoelectric conversion element 72 and TFT 82 are not provided. It may be more than the active agent. As the amount of the activator increases, the amount of fluorescence emitted from the phosphor 122 increases.

  When the phosphor is kneaded into the plastic or the like used as the support substrate 120, by controlling the stirring force, the phosphor 122 is cured while being settled, and the particle distribution of the phosphor 122 as shown in FIG. 7 is created. be able to.

  In FIG. 7, the particle size and particle density of the phosphor 122 are divided into two stages, but the particle size and particle density of the phosphor 122 may be divided into three or more stages. In the case of dividing into three or more stages, the particle size and particle density of the phosphor 122 may be increased and increased as the side closer to the side where the photoelectric conversion element 72 and the like of the support substrate 120 are provided. In FIG. 7, the particle size and particle density of the phosphor 122 are divided stepwise (although they are divided so that the interface 124 is generated), the particle size and particle density of the phosphor 122 are changed. You may change gradually so that an interface may not arise. That is, the particle size and particle density of the phosphor 122 may be gradually increased and increased as the support substrate 120 is closer to the side where the photoelectric conversion element 72 and the like are provided. Similarly, as the amount of the activator is closer to the side where the photoelectric conversion element 72 and the TFT 82 are provided, the amount of the activator of the phosphor 122 is gradually increased so as not to cause an interface. May be more.

  Further, since the support substrate 120 contains a large amount of aramid and bionanofiber, the thermal expansion coefficient of the support substrate 120 can be made substantially uniform even if the particle distribution of the phosphor 122 as shown in FIG. 7 is made. When the support substrate 120 does not include aramid and bio-nanofiber, the location where the phosphor 122 is large tends to have a low coefficient of thermal expansion, and the location where the phosphor 122 is small tends to have a high coefficient of thermal expansion. Note that the thermal expansion coefficient of the support substrate 120 changes according to the ratio of the support substrate 120 including aramid and bio-nanofiber, and the greater the ratio of aramid and bio-nanofiber, the lower the thermal expansion coefficient. The coefficient of thermal expansion can be made substantially constant.

  Thus, the phosphor 122 located farther from the photoelectric conversion element 72 has smaller particles, and thus the phosphor 122 located farther from the photoelectric conversion element 72 is less likely to diffuse the emitted fluorescence. Thereby, the spread range of the fluorescence when it reaches the photoelectric conversion element 72 can be narrowed, blurring of the captured radiographic image can be suppressed, and the image quality of the radiographic image can be improved.

  Since the density of the particles is smaller as the phosphor 122 is farther from the photoelectric conversion element 72, the amount of fluorescence emitted is smaller as the phosphor 122 is farther from the photoelectric conversion element 72. Thereby, blur of the radiographic image to be captured can be suppressed, and the image quality of the radiographic image can be improved. Further, since the phosphor 122 located farther from the photoelectric conversion element 72 has a smaller amount of activator, the phosphor 122 located farther from the photoelectric conversion element 72 has a smaller amount of emitted fluorescence, and imaging. Therefore, it is possible to suppress blurring of the radiographic image, and to improve the image quality of the radiographic image. In FIG. 7, the photoelectric conversion element 72 and the TFT 82 are represented by one layer. However, as illustrated in FIG. 6, the photoelectric conversion element 72 and the TFT 82 may be formed of two layers.

The photoelectric conversion element 72 may be formed of an organic photoelectric conversion material, and a flexible TFT layer may be realized by a CMOS circuit including a TFT 82 made of an organic material. In this case, pentacene may be adopted as the material of the p-type organic semiconductor used in the CMOS circuit, and copper fluoride phthalocyanine (F ₁₆ CuPc) may be adopted as the material of the n-type organic semiconductor. As a result, a flexible TFT layer capable of having a smaller bending radius can be realized. In addition, by configuring the TFT layer in this way, the gate insulating film can be significantly thinned, and the driving voltage can be lowered. Furthermore, the gate insulating film, the semiconductor, and each electrode can be manufactured at room temperature or 100 ° C. or lower. Furthermore, a CMOS circuit can be directly formed over the flexible support substrate 120. Moreover, the TFT 82 made of an organic material can be miniaturized by a manufacturing process in accordance with a scaling law. Note that the support substrate 120 can be realized by applying a polyimide precursor onto a thin polyimide substrate by spin coating and heating, so that the polyimide precursor changes to polyimide, so that a flat substrate without unevenness can be realized. .

  Further, by applying a self-alignment arrangement technique (Fluidic Self-Assembly method) in which a plurality of micron-order device blocks are arranged at specified positions on the substrate, the photoelectric conversion element 72 and the TFT 82 made of crystalline Si are made of a resin substrate. You may arrange | position on the support substrate 120. FIG. In this case, the photoelectric conversion element 72 and the TFT 82 as micro device blocks of micron order are prepared in advance on another substrate and then separated from the substrate, and the photoelectric conversion element 72 and the TFT 82 are used as a target substrate in a liquid. Spread over 120 and place statistically. The support substrate 120 is preliminarily processed to fit the device block, and the device block can be selectively placed on the support substrate 120. Therefore, an optimum device block (photoelectric conversion element 72 and TFT 82) made of an optimum material can be integrated on an optimum substrate (support substrate 120), and photoelectric support can be applied to a non-crystal support substrate 120 (resin substrate). The conversion element 72 and the TFT 82 can be integrated.

  The above embodiment can be modified as follows.

(Modification 1)
In the above embodiment, the photoelectric conversion element and the TFT are formed only on one side of the support substrate 120, but the photoelectric conversion element and the TFT may be formed on both sides of the support substrate 120. In this case, radiation images can be read from both sides, and two radiation images can be obtained simultaneously.

  FIG. 8 is a diagram schematically illustrating an example of a cross section of the radiation conversion panel of the first modification. In the radiation conversion panel 70 of this modification, a photoelectric conversion element (second photoelectric conversion element) 130 and a TFT (second switching) are further provided on the side of the support substrate 120 shown in FIG. 5 where the photoelectric conversion element 72 and the TFT 82 are not formed. Element) 132 is formed.

  At least one of the photoelectric conversion element 72 and the photoelectric conversion element 130 may be formed using an organic photoelectric conversion material. As described above, since the organic photoelectric conversion material does not absorb electromagnetic waves other than the fluorescence emitted by the phosphor 122 (since it transmits X-rays), a photoelectric conversion element formed using the organic photoelectric conversion material is provided. The other side may be the radiation irradiation side. An inorganic photoelectric conversion material such as amorphous silicon has the property of absorbing X-rays and deteriorates due to the absorption of X-rays, so the side on which the photoelectric conversion element formed of the inorganic photoelectric conversion material is provided It may be the side.

  In FIG. 8, it is assumed that the photoelectric conversion element 130 on the irradiation side is molded from an organic photoelectric conversion material, and the photoelectric conversion element 72 on the back side is molded from an inorganic photoelectric conversion material. Thereby, the lifetime of the photoelectric conversion element 72 shape | molded with the inorganic photoelectric conversion material can be extended. Moreover, since the radiation irradiated from the irradiation side and having passed through the support substrate 120 is absorbed by the photoelectric conversion element 72 that is an inorganic photoelectric conversion material on the back surface side, the amount of radiation leaking from the back surface side can be reduced. Further, since the photoelectric conversion element 130 formed of an organic photoelectric conversion material is provided on the radiation side, radiation attenuation by the photoelectric conversion element 130 can be reduced. Therefore, the irradiated radiation can be incident on the support substrate 120 without being attenuated to the left.

  FIG. 9 is a diagram schematically illustrating another example of a cross section of the radiation conversion panel of the first modification. The radiation conversion panel 70 of this modification is obtained by further forming a photoelectric conversion element 130 and a TFT 132 on the side of the support substrate 120 of the radiation conversion panel 70 shown in FIG. 7 where the photoelectric conversion element 72 and the TFT 82 are not formed. . At least one of the photoelectric conversion element 72 and the photoelectric conversion element 130 may be formed using an organic photoelectric conversion material, and the side on which the photoelectric conversion element formed using the organic photoelectric conversion material is provided is radiation. It is good also as the irradiation side.

  In FIG. 9, the photoelectric conversion element 130 is molded from an organic photoelectric conversion material, and the photoelectric conversion element 72 is molded from an inorganic photoelectric conversion material such as amorphous silicon. When the support substrate 120 does not contain aramid and bionanofiber, or when the content of aramid and bionanofiber is low, the side of the support substrate 120 on which the photoelectric conversion element 130 is provided is the side on which the photoelectric conversion element 72 is provided. The coefficient of thermal expansion is higher than This is because the difference in expansion coefficient is due to the difference in the amount of phosphor 122 kneaded. The organic photoelectric conversion material has a higher coefficient of thermal expansion than amorphous silicon. Accordingly, the photoelectric conversion element 130 formed from an organic photoelectric conversion material and the side of the support substrate 120 on which the photoelectric conversion element 130 is provided have a high coefficient of thermal expansion, and thus the support substrate 120 and the photoelectric conversion element 130 are separated. There is nothing.

  8 and 9, the TFT 132 may be formed using an amorphous oxide semiconductor (IGZO). In addition, although the side where the photoelectric conversion element 130 is provided is the irradiation side, the side where the photoelectric conversion element 72 is provided may be the irradiation side. 8 and 9, the photoelectric conversion element 130 and the TFT 132 are represented by one layer, but the photoelectric conversion element 130 and the TFT 132 may be formed by two layers.

  8 and 9, the photoelectric conversion element 130 is formed using an organic photoelectric conversion material, the photoelectric conversion element 72 and the TFTs 82 and 132 are formed using IGZO, and a GOS: A phosphor 122 of Tb is kneaded. When the radiation conversion panel 70 is irradiated with radiation, the GOS: Tb phosphor 122 emits green light, and the polyethylene terephthalate emits light having a peak at 370 nm. The fluorescence emitted by the phosphor 122 of GOS: Tb is absorbed by the photoelectric conversion element 130 formed of an organic photoelectric conversion material, and the light emitted by polyethylene terephthalate is absorbed by the photoelectric conversion element 72 formed using IGZO. Is done. Sensitivity can be improved by receiving light emitted from the polyethylene terephthalate of the support substrate 120.

  Furthermore, in the said embodiment and the modification 1, the photoelectric conversion elements 72 and 130 are comprised with a flexible organic photoelectric conversion material, and TFT82 and 132 are also comprised with a flexible organic material, The radiation conversion panel 70 is made flexible. The radiation conversion panel 70 can function as a flexible CMOS sensor made of an organic material. Thereby, it becomes possible to make the panel part 32 flexible, and portability can be improved by winding the panel part 32 at the time of conveyance.

(Modification 2)
In the above embodiment, as shown in FIG. 2, the electronic cassette 20 in which the control unit 34 is provided on the imaging surface 42 outside the imaging region of the panel unit 32 has been described. The electronic cassette 20 having such a form may be used. 10 and 11, the same components as those shown in FIG. 2 are denoted by the same reference numerals, and only the portions different from FIG. 2 will be described.

  FIG. 10 is a perspective view of an electronic cassette in which a panel unit and a control unit according to Modification 2 are stacked. In the electronic cassette 20, a panel unit 32 is laminated on a control unit 34. The upper surface of the panel unit 32 is an imaging surface 42 including the imageable region 36 and the guide line 44, and the control unit 34 is provided on the opposite side of the panel unit 32 from the side where the imaging surface 42 is provided. Radiation imaging can be performed by placing a patient as a subject on the imaging surface 42 and irradiating the patient with radiation. In the case of the electronic cassette 20 in which the panel unit 32 and the control unit 34 are laminated, the incidence of radiation transmitted through the panel unit 32 on the control unit 34 causes a failure of the control unit 34. A shielding plate (not shown) that does not transmit radiation is provided between the control unit 34. In FIG. 10, for ease of understanding, the panel unit 32 and the control unit 34 are separated from each other, and the panel unit 32 and the control unit 34 are bonded to each other. 34 may be housed in one housing.

  FIG. 11 is a diagram illustrating the electronic cassette 20 that can be folded by joining the panel unit 32 and the control unit 34 of Modification 2 with a hinge 134. As shown in FIG. 11A, the electronic cassette 20 is in a folded state during transportation, and the panel unit 32 and the control unit 34 are overlaid. At the time of use, as shown in FIG. 11B, the electronic cassette 20 is unfolded by rotating the panel part 32 around the hinge 134 in a direction away from the control part 34. As shown in FIG. 11C, when the panel unit 32 is expanded, an imaging surface 42 including 36 indicating the imageable area and the guide line 44 appears. Radiation imaging can be performed by placing a patient as a subject on the imaging surface 42 and irradiating the patient with radiation.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Radiation imaging system 12 ... Imaging stand 14 ... Subject 16 ... Radiation 18 ... Radiation source 20 ... Electronic cassette 24 ... Console 26 ... Display apparatus 28 ... Radiology information system 30 ... Medical information system 32 ... Panel part 34 ... Control part 70 ... Radiation conversion panel 72 ... Photoelectric conversion element 82 ... TFT 120 ... Support substrate 122 ... Phosphor 124 ... Interface 130 ... Second photoelectric conversion element 132 ... TFT
134 ... Hinge

Claims (4)

A support substrate that also functions as a scintillator sensitive to radiation in which a phosphor is kneaded;
A first photoelectric conversion element formed on the support substrate and sensitive to fluorescence emitted by the phosphor, and a first switching element for outputting a signal of the first photoelectric conversion element;
Equipped with a,
The side of the support substrate on which the first photoelectric conversion element and the first switching element are provided has a larger size of the incorporated phosphor particles than the side on which the first photoelectric conversion element is not provided. Satisfying at least one of the following conditions: a high density of the kneaded phosphor particles, and a large amount of the kneaded activator;
On the side of the support substrate where the first photoelectric conversion element and the first switching element are not provided, a second photoelectric conversion element having sensitivity to fluorescence emitted by the phosphor, and a second photoelectric conversion element A second switching element for outputting a signal is formed;
The second photoelectric conversion element is molded using an organic photoelectric conversion material,
The first photoelectric conversion element is formed by using an inorganic photoelectric conversion material, and the radiation conversion panel. The radiation conversion panel according to claim 1,
The radiation conversion panel, wherein the first photoelectric conversion element and the first switching element are formed in contact with the support substrate. The radiation conversion panel according to claim 1,
The first photoelectric conversion element is formed in contact with the support substrate, and the first switching element is formed on the support substrate with the first photoelectric conversion element interposed therebetween. Radiation conversion panel. The radiation conversion panel according to any one of claims 1 to 3 ,
At least one of said 1st switching element and said 2nd switching element is shape | molded using the oxide semiconductor. The radiation conversion panel characterized by the above-mentioned.

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