Radiographic imaging panels, devices, systems, and scintillator sheets

Abstract

The present invention provides a radiographic imaging panel, device, system, and scintillator sheet. The radiographic imaging panel includes a substrate on which a plurality of pixels, each including a photoelectric conversion element, are arranged, a scintillator arranged on the substrate, and a protective layer arranged to cover the scintillator. The scintillator includes a plurality of columnar crystals containing an alkali metal halide. The protective layer includes a resin layer containing a resin to which metal oxide particles are added. The thickness of the resin layer from the apex of each of the plurality of columnar crystals to the upper surface of the resin layer is greater than or equal to 10 μm and less than 30 μm, and the particle concentration in the resin layer is greater than or equal to 0.15 vol% and less than 7.5 vol%.

Description

Technical Field

[0001] The present invention relates to a radiation imaging panel, a radiation imaging device, a radiation imaging system, and a scintillator sheet. Background Art

[0002] Flat panel detectors (FPDs) used in radiography for applications such as medical image diagnosis and non-destructive testing include indirect-conversion FPDs, which convert radiation that has passed through a subject into light using a scintillator and detect the light emitted by the scintillator using a photoelectric conversion element. Columnar crystals of alkali metal halides, such as cesium iodide, are widely used for converting radiation into light. To effectively transmit the light converted from the radiation to the photoelectric conversion element, alkali metal halides degrade due to moisture absorption. Therefore, a moisture-proof protective layer may be placed over the scintillator. Furthermore, a light-reflecting reflective layer may be placed on the side of the scintillator opposite the photoelectric conversion element, enabling the photoelectric conversion element to effectively detect the light converted from the radiation by the scintillator. Japanese Patent Application Laid-Open No. 2006-052980 discloses a radiation detection device including a phosphor protective layer made of a resin containing fine light-reflecting particles and having moisture-proof and light-reflective properties relative to the phosphor layer. Summary of the Invention

[0003] The dispersion concentration of the fine light-reflecting particles disclosed in Japanese Patent Application Laid-Open No. 2006-052980 requires further consideration. More specifically, if the concentration of the fine light-reflecting particles is too low, the effect of reflecting light will become insufficient, which may result in an insufficient effect of improving the MTF (Modulation Transfer Function). On the other hand, Japanese Patent Application Laid-Open No. 2006-052980 discloses the use of metal oxides such as TiO2 as fine light-reflecting particles, which transmit light entering at an angle of the critical angle or less. However, if the concentration of the fine light-reflecting particles is too high, the probability of light entering the fine light-reflecting particles at a narrow angle equal to or less than the critical angle increases. Furthermore, if the concentration of the fine light-reflecting particles is high and the particles are in contact with each other, light that has passed through one fine light-reflecting particle may enter another fine light-reflecting particle, and thus the light may diffuse. As a result, the light reflection effect becomes insufficient, which may result in an insufficient effect of improving the MTF.

[0004] Furthermore, the thickness of the phosphor protective layer, in which fine light-reflecting particles are dispersed, requires further consideration. If the phosphor protective layer is too thick, light will diffuse within it, potentially inadequately improving the MTF. On the other hand, if the protective layer is too thin, moisture resistance may be insufficient.

[0005] An embodiment of the present invention provides a technique that is advantageous for improving the MTF in a radiographic panel.

[0006] According to some embodiments, a radiation imaging panel includes: a substrate on which a plurality of pixels are arranged, each pixel including a photoelectric conversion element; a scintillator arranged above the substrate; and a protective layer arranged to cover the scintillator, wherein the scintillator includes a plurality of columnar crystals containing an alkali metal halide, the protective layer includes a resin layer containing a resin to which metal oxide particles are added, the thickness of the resin layer from the apex of each of the plurality of columnar crystals to the upper surface of the resin layer is greater than or equal to 10 μm and less than 30 μm, and the particle concentration in the resin layer is greater than or equal to 0.15 vol% and less than 7.5 vol%.

[0007] According to some other embodiments, a scintillator sheet includes: a substrate; a scintillator arranged on the substrate; and a protective layer arranged to cover the scintillator, wherein the scintillator includes a plurality of columnar crystals containing alkali metal halide, the protective layer includes a resin layer containing a resin added with metal oxide particles, the thickness of the resin layer from the apex of each columnar crystal in the plurality of columnar crystals to the upper surface of the resin layer is greater than or equal to 10 μm and less than 30 μm, and the particle concentration in the resin layer is greater than or equal to 0.15 vol% and less than 7.5 vol%.

[0008] Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A and Figure 1B is a cross-sectional view showing a configuration example of a radiation imaging panel according to the embodiment;

[0010] Figure 2 It shows Figure 1A and Figure 1B A cross-sectional view showing an example of the configuration of a protective layer of a radiation imaging panel shown in FIG.

[0011] Figure 3 It shows Figure 1A and Figure 1B Graph showing the characteristics of the radiographic panel shown in ;

[0012] Figure 4 It shows Figure 1A and Figure 1B Graph showing the characteristics of the radiographic panel shown in FIG.

[0013] Figure 5 It shows Figure 1A and Figure 1B FIG is a SEM image of a cross section of the radiographic plate shown in ;

[0014] Figure 6 It shows Figure 1A and Figure 1B Graph showing the characteristics of the radiographic panel shown in ;

[0015] Figure 7 It shows Figure 1A and Figure 1B Graph showing the characteristics of the radiographic panel shown in FIG.

[0016] Figure 8 Is shown using Figure 1A and Figure 1B A diagram showing a configuration example of a radiation imaging device and a radiation imaging system including a radiation imaging panel shown in FIG; and

[0017] Figure 9A and Figure 9B Is used to illustrate Figure 1A and Figure 1B The problem of the resin layer of the radiographic plate is shown in FIG. DETAILED DESCRIPTION

[0018] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the scope of the claimed invention. While a plurality of features are described in the embodiments, the invention is not limited to all of these features, and a plurality of such features may be appropriately combined. In addition, in the accompanying drawings, the same reference numerals are assigned to the same or similar structures, and their redundant description is omitted.

[0019] The radiation in the present invention includes α rays, β rays and γ rays, which are beams formed by particles (including photons) emitted by radioactive decay. The radiation may also include beams with energy equal to or higher than the energy of the above beams, such as X-rays, particle beams and cosmic rays.

[0020] The following will refer to Figures 1A to 9B The arrangement of the radiation imaging panel according to the embodiment will be described. Figure 1A 2 is a diagram showing a cross-sectional structure of the radiation imaging panel 100 according to the present embodiment. Figure 1B yes Figure 1A An enlarged view of portion 111 is shown.

[0021] The radiation imaging panel 100 includes a substrate 101 having a pixel region 105 in which a plurality of pixels each including a photoelectric conversion element is arranged, a scintillator 108 arranged on the substrate 101, and a protective layer 110 arranged to cover the scintillator 108. The scintillator 108 includes a plurality of columnar crystals 102 containing an alkali metal halide. The protective layer 110 includes a resin layer 104 containing a resin 103 to which particles 106 of a metal oxide are added. A pixel protection layer 107 for protecting the pixels arranged in the pixel region 105 may also be formed between the substrate 101 and the scintillator 108.

[0022] In the pixel area 105, a plurality of pixels can be arranged in the form of a two-dimensional array. For example, 3300×2800 pixels can be arranged on a substrate 101 of 550 mm×445 mm. Among the 3300×2800 pixels, 10 pixels arranged on the periphery can be used as a dummy pixel area, and an effective pixel area of ​​the pixel area 105 can be formed by using 3280×2780 pixels arranged within the dummy pixels. The number of pixels to be arranged in the pixel area 105 and the number of pixels to be arranged in the effective pixel area of ​​the pixel area 105 can be appropriately set according to, for example, the size of the substrate 101 and the subject to be imaged.

[0023] In the pixel region 105, column signal lines for extracting signals generated in each pixel and row signal lines for driving the components including these pixels arranged in the pixel region 105 can be formed. The column signal lines and row signal lines can be electrically connected to the readout circuit substrate and the drive circuit substrate via a flexible printed circuit board. To connect the column signal lines and row signal lines to the readout circuit substrate and the drive circuit substrate, the substrate 101 can have a connection terminal portion (not shown). The signals generated in each pixel of the pixel region 105 can be output from the radiation imaging board 100 via the connection terminal portion.

[0024] In this example, the reading circuit and the driving circuit are arranged outside the radiation imaging panel 100. However, the reading circuit and the driving circuit may be arranged in the radiation imaging panel 100. Even in this case, a connection terminal portion (not shown) may be arranged over the substrate 101, and a signal generated in each pixel of the pixel area 105 may be output from the radiation imaging panel 100 via the connection terminal portion (not shown).

[0025] like Figure 1A As shown, a resin layer 104 in which metal oxide particles 106 are dispersed in a resin 103 is disposed on the side of the scintillator 108 opposite to the pixel region 105. This makes it possible to effectively utilize light generated by the scintillator 108 and improve the sensitivity of the radiation imaging panel 100.

[0026] The scintillator 108 formed of the plurality of columnar crystals 102 containing an alkali metal halide deteriorates due to moisture absorption. Therefore, the resin layer 104 in which the metal oxide particles 106 are dispersed in the resin 103 can also serve as a moisture-proof layer for the scintillator 108. When the resin layer 104 covering the scintillator 108 also serves as a moisture-proof layer, degradation of the scintillator 108 due to moisture absorption can be suppressed.

[0027] Figure 1B 1 is a diagram for explaining the function of the resin layer 104 in which the metal oxide particles 106 are dispersed in the resin 103. Figure 1B As shown, light emitted from the columnar crystals of the scintillator 108 toward the resin 103 is reflected by the dispersed particles 106 through specular reflection or diffuse reflection. A portion of the light reflected by the particles 106 returns to the columnar crystals 102 that emitted the light. Another portion of the light reflected by the particles 106 is attenuated by repeated reflection by other particles. In other words, light can be prevented from diffusing and propagating in the resin layer 104. This indicates that a high MTF (Modulation Transfer Function) can be achieved by the resin layer 104 in which the metal oxide particles 106 are dispersed in the resin 103.

[0028] However, if Figure 9A As shown in FIG. 1 , if the number of particles 106 is small, the reflective effect of the metal oxide particles 106 may not be obtained. Figure 9B As shown, if the concentration of metal oxide particles 106, such as TiO2, which transmit light entering at an angle less than or equal to the critical angle, is too high, the probability of light entering at a narrow angle equal to or less than the critical angle increases. Furthermore, if the concentration of fine light-reflecting particles is high and the particles are in contact with each other, light transmitted through one fine light-reflecting particle may enter another fine light-reflecting particle and diffuse. As a result, the light reflection effect becomes insufficient, which may lead to an insufficient MTF improvement effect. The appropriate concentration of metal oxide particles 106 and the appropriate thickness of resin layer 104 will be described later.

[0029] Next, a method for manufacturing the radiation imaging panel 100 will be described. For example, 550 mm × 445 mm alkali-free glass with a thickness of 500 μm can be used as the substrate 101. The pixel region 105 is formed by repeatedly performing deposition steps, photolithography steps, etching steps, and the like on the glass substrate 101. In the pixel region 105, a plurality of pixels are arranged, each including a light conversion element for generating a charge corresponding to the light emission of the scintillator 108 and a switching element for outputting a signal corresponding to the generated charge. Furthermore, a connection terminal portion (not shown) for driving the pixels and transmitting the obtained signal to an external circuit is formed in the pixel region 105.

[0030] After forming the pixel region 105, an array inspection may be performed to inspect the operation of the pixels formed in the pixel region 105. After confirming good operation and no or only a few defective pixels through the array inspection, a pixel protection layer 107 for protecting the connection terminal portion (not shown) may be formed by masking the periphery of the substrate 101 with a masking film. The pixel protection layer 107 may be formed by, for example, placing the substrate 101 in a spray spin coater, rotating the substrate 101 at a rotation speed of approximately 100 rpm while spraying a polyimide solution, and then drying and annealing the substrate 101 at a temperature of 220°C. The pixel protection layer 107 may have a thickness of, for example, approximately 2 μm.

[0031] Then, the scintillator 108 is formed. First, a vapor deposition mask is set on the area of ​​the substrate 101 on which the pixel protection layer 107 is formed, where the scintillator 108 is not formed, and the substrate 101 is set in a vapor deposition device so that the pixel protection layer 107 is a vapor deposition surface. Thereafter, a cell vessel is filled with cesium iodide (CsI) and thallium iodide (TlI) so that the Tl concentration is 1 mol% relative to CsI, and these materials are heated for co-deposition. The scintillator 108 can have a thickness of, for example, 380 μm and a film filling rate of 75%. In this state, the outer edge of the scintillator 108 can be arranged outside the outer edge of the pixel area 105. When performing the vapor deposition of the scintillator 108, the vapor deposition device can also be evacuated to 10 -3 Pa, and heating was performed using a lamp heater so that the substrate surface temperature became 175°C.

[0032] The protective layer 110 can also be formed as follows. Figure 2 1 is a diagram showing an example of the structure of the protective layer 110. In the protective layer 110 of this embodiment, an aluminum metal layer 202 is arranged on a substrate 201, and a resin layer 104 containing a resin 103 to which metal oxide particles 106 are added is arranged on the metal layer 202. The resin layer 104 of the protective layer 110 may be in contact with the scintillator 108. The protective layer 110 is not limited to Figure 2 For example, another layer such as a resin layer without metal oxide particles added may be further stacked on the protective layer 110. Alternatively, the protective layer 110 may include only the resin layer 104 or may have a two-layer structure including the resin layer 104 and the metal layer 202.

[0033] In this embodiment, a hot-melt resin primarily containing a polyolefin resin is used as the resin 103 forming the resin layer 104. A hot-melt resin is defined as an adhesive resin that contains neither water nor solvent, is solid at room temperature, and is made of a 100% non-volatile thermoplastic material (Thomas P. Flanagan, Adhesives Age, vol. 9, No. 3, pp. 28 (1966)). Furthermore, a hot-melt resin has the property of melting when the resin temperature rises and solidifying when the resin temperature drops. A hot-melt resin is a resin that adheres to another organic material and an inorganic material in a heated and molten state, but does not adhere in a solid state at room temperature. Furthermore, the hot-melt resin does not contain any of polar solvating media, solvents, or water. Therefore, even when the hot-melt resin comes into contact with the scintillator 108 having the alkali metal halide columnar crystals 102, the hot-melt resin does not dissolve the scintillator 108, and thus the hot-melt resin can also function as a protective layer.

[0034] Hot melt resins are classified according to the type of base polymer (base material) as a main component, and polyolefin-based, polyester-based, and polyamide-based resins can be used. When using a hot melt resin as the protective layer 110 of the scintillator 108, it is important that the resin has high moisture resistance and high light transmittance that transmits visible light generated from the scintillator 108.

[0035] Resin layer 104 is formed as follows. For example, a polyolefin resin serving as resin 103 is dissolved in a toluene-xylene solvent mixture, and the viscosity is adjusted to approximately 10 cps. Furthermore, metal oxide particles 106 are pre-dispersed in a solution mixture of butanol and propanol along with a dispersant. A dispersion prepared by thoroughly pulverizing the polyolefin resin dissolved in the toluene-xylene solution mixture using a ball mill is added to the mixture so that the particles 106 constitute 0 to 32 vol% of the resin layer 104, followed by mixing. After the dispersion is thoroughly stirred, the solvent is evaporated while preventing foaming, thereby obtaining resin layer 104.

[0036] A material with a higher refractive index than that of the scintillator 108 can be used as the metal oxide particles 106. For example, when CsI (refractive index (n): 1.78 to 1.84 (depending on the type of activator, etc.)) is used as the alkali metal halide scintillator 108, a material with a higher refractive index than CsI can be used. The metal oxide particles 106 can contain at least one selected from the group consisting of, for example, white lead (2PbCo3·Pb(OH)2) (n: 1.94 to 2.09), zinc oxide (n: 2.0), yttrium oxide (n: 1.91), zirconium oxide (n: 2.20), and titanium oxide (n: 2.50 to 2.72). For example, the refractive index of the metal oxide particles 106 can be greater than or equal to 1.94 and less than or equal to 2.72. This embodiment will be described assuming that rutile titanium dioxide particles, which have a higher refractive index than other types of titanium oxides, are used as the metal oxide.

[0037] In addition, the average particle size of the metal oxide particles 106 can be greater than or equal to 200 nm and less than or equal to 500 nm. The sensitivity characteristics of the photoelectric conversion element are generally 500 nm to 800 nm, but if the particle size is 1 / 2 of the wavelength of light or less, the influence of Rayleigh scattering occurs, which increases the probability of reflection in the incident direction of light. As the metal oxide particles 106, this embodiment uses particles with an average particle size of 250 nm and a particle size distribution of 10% diameter D 10 =195μm, 50% diameter (median diameter) D 50 = 245 μm and 90% diameter D 90 =275μm rutile titanium dioxide particles.

[0038] A PET substrate or the like can be used as the base 201. The protective layer 110 of this embodiment is obtained by forming a resin layer 104 to which metal oxide particles 106 are added on a film obtained by forming a 12 μm thick aluminum metal layer 202 on a 30 μm thick PET base 201. The protective layer 110 can be formed by, for example, placing the base 201 formed with the metal layer 202 in a roll coater apparatus and coating the metal layer 202 with the resin 103 to which the particles 106 prepared as described above are added. Thus, the protective layer 110 includes the base 201 disposed on the side of the resin layer 104 opposite to the scintillator 108, and the metal layer 202 formed between the resin layer 104 and the base 201.

[0039] When the present inventors actually formed the protective layer 110, if the thickness of the resin layer 104 was less than 10 μm, it was difficult to obtain film thickness uniformity of the resin layer 104. That is, the resin layer 104 needed to have a thickness of 10 μm or more.

[0040] The radiation imaging panel 100 can be manufactured on the substrate 201 by adhering the protective layer 110 including the resin layer 104 having a desired thickness and in which the metal oxide particles 106 having a desired concentration are dispersed, on the scintillator 108 .

[0041] For example, the protective layer 110 formed is cut according to the size of the scintillator 108 of the substrate 101, and the protective layer 110 is set in a vacuum thermal transfer device. In addition, the substrate 101 formed with the scintillator 108 is set in the vacuum thermal transfer device so as to face the protective layer 110. After the base 201 and the substrate 101 are aligned by using the alignment mark, the substrate 101 and the protective layer 110 are brought into contact with each other at 30°C and the pressure is reduced to 10 -1 Pa is used to remove air bubbles. In addition, the substrate 101 on which the scintillator 108 is formed and the protective layer 110 are adhered by first heating the substrate 101 and the protective layer 110 together to 70 to 100° C. under pressure and then maintaining them in this state for an appropriate time.

[0042] Subsequently, a drive substrate and the like are connected to a connection terminal portion (not shown) of the substrate 101 to which the protective layer 110 is attached via an anisotropic conductive film or the like. Furthermore, a sheet for increasing strength is attached to the side of the substrate 101 opposite to the scintillator 108. In this manner, the radiation imaging panel 100 of this embodiment is obtained.

[0043] The relationship between the concentration of the metal oxide particles 106 , the thickness of the resin layer 104 , and the MTF in the radiation imaging panel 100 will be described below. Figure 3 and Figure 4 Graphs showing the characteristics of radiographic panels 100 manufactured by varying the concentration of metal oxide particles 106 and the thickness of the resin layer 104. The characteristics of the radiographic panels 100 were evaluated by setting the radiographic panels 100 in a drive system and irradiating them with X-rays of radiation quality RQA5 that conforms to international standards, thereby measuring MTF and DQE (quantum detection efficiency). The MTF and DQE values ​​at a volume ratio of 2 lp / mm for the metal oxide particles 106 in the resin layer 104 and at a thickness t of the resin layer 104 were obtained. Figure 3 are shown in the form of a list and in Figure 4 The thickness t of the resin layer 104 is expressed as a range obtained by observing a plurality of SEM images because the height of the phosphor varies with the pillars in practice.

[0044] like Figure 1BAs shown, the thickness t of the resin layer 104 is the thickness from the apex of each of the plurality of columnar crystals 102 in the resin layer 104 to the upper surface of the resin layer 104. The apex of each columnar crystal 102 may be the portion of the columnar crystal 102 farthest from the substrate 101. After manufacturing the radiation imaging plate 100, the thickness t of the resin layer 104 can be measured by cutting out a small piece, exposing the cut cross section with a chemical polishing device, and taking an SEM image of the cross section. Figure 5 The SEM image shows the columnar crystals 102 of the scintillator 108 and the resin layer 104 of the protective layer 110. The thickness t of the resin layer 104 can be controlled by the thickness of the resin 103 when forming the protective layer 110 and the heating temperature and holding time in the vacuum thermal transfer device.

[0045] Figure 3 and Figure 4 The figure shows that when the thickness t of the resin layer 104 is less than 30 μm, the improvement trend of the MTF changes with respect to the volume ratio of the metal oxide particles 106. In addition, when the thickness of the resin layer 104 is less than 30 μm, the MTF increases if the concentration of the metal oxide particles 106 in the resin 104 is greater than or equal to 0.15 vol% and less than 7.5 vol%. Figure 3 It is also revealed that within the range of the thickness of the formed resin layer 104 and the range of the concentration of the metal oxide particles 106 , the DQE value is hardly affected by the thickness of the resin layer 104 and the concentration of the metal oxide particles 106 .

[0046] As can be seen from the foregoing, the thickness t of the resin layer 104 from the apex of each of the plurality of columnar crystals 102 in the resin layer 104 to the upper surface of the resin layer 104 is greater than or equal to 10 μm and less than 30 μm, and the concentration of the metal oxide particles 106 in the resin layer 104 is greater than or equal to 0.15 vol% and less than 7.5 vol%. This makes it possible to improve the MTF characteristics of the radiographic panel 100 while maintaining the DQE characteristics.

[0047] In the above-described embodiment, a case has been described in which a hot-melt resin is used as the resin 103 to be used in the resin layer 104. However, the resin 103 is not limited to the hot-melt resin. As the resin 103 to be used in the resin layer 104, for example, a resin having pressure-sensitive adhesiveness obtained by intermolecular force, that is, a resin as a so-called adhesive can also be used. In this case, a material having a refractive index lower than that of the scintillator 108 can be used as the resin 103. For example, the resin 103 can contain at least one selected from the group consisting of a polyurethane resin (n: 1.49) and an acrylic resin (n: 1.49 to 1.53). That is, the refractive index of the resin 103 can be, for example, greater than or equal to 1.49 and less than or equal to 1.53. For example, a polymethyl methacrylate resin (n: 1.491) as an acrylic resin can be used as the resin 103.

[0048] With the above Figure 3 and Figure 4 similar, Figure 6 and Figure 7 104. The graph shows the characteristics of the radiographic panel 100 manufactured by changing the concentration of the metal oxide particles 106 and the thickness of the resin layer 104. Figure 6 and Figure 7 The radiation imaging panel 100 having the characteristics shown is the same as the radiation imaging panel 100 described above. When an acrylic resin is used as the resin 103, for example, the protective layer 110 can be formed by transferring the resin layer 104 onto the base 201 formed with the metal layer 202 using a roll laminator. Furthermore, the radiation imaging panel 100 can be manufactured by attaching the protective layer 110 to the scintillator 108 on the base 101 using a roll laminator and performing pressure degassing.

[0049] like Figure 6 and Figure 7 As shown in FIG. 1 , even when an acrylic resin is used as the resin 103, if the thickness t of the resin layer 104 is less than 30 μm, the improvement tendency of the MTF changes with respect to the volume ratio of the metal oxide particles 106. Furthermore, when the thickness of the resin layer 104 is less than 30 μm, if the concentration of the metal oxide particles 106 in the resin layer 104 is greater than or equal to 0.15 vol% and less than 7.5 vol%, the MTF increases. Figure 6 It is also revealed that within the range of the thickness of the formed resin layer 104 and the range of the concentration of the metal oxide particles 106 , the DQE value is hardly affected by the thickness of the resin layer 104 and the concentration of the metal oxide particles 106 .

[0050] As can be seen from the foregoing, the thickness t of the resin layer 104 from the apex of each of the plurality of columnar crystals 102 in the resin layer 104 to the upper surface of the resin layer 104 is greater than or equal to 10 μm and less than 30 μm, and the concentration of the metal oxide particles 106 in the resin layer 104 is greater than or equal to 0.15 vol% and less than 7.5 vol%. This makes it possible to improve the MTF characteristics of the radiographic panel 100 while maintaining the DQE characteristics.

[0051] In the present embodiment, particles of rutile titanium dioxide are used as the metal oxide particles 106. However, even when the above-mentioned metal oxides (e.g., white lead, zinc oxide, yttrium oxide, and zirconium oxide) are used, by controlling the concentration of the metal oxide particles 106 and the thickness of the resin layer 104 as described above, the MTF characteristics of the radiation imaging panel 100 can be improved while maintaining the DQE characteristics.

[0052] Furthermore, this embodiment describes a case where the substrate 101 includes a pixel region 105 with multiple pixels arranged therein, but the present invention is not limited thereto. For example, the substrate 101 need not include the pixel region 105. In this case, the component denoted by reference numeral 100 may be referred to as a scintillator sheet. For example, when this scintillator sheet is mounted on a sensor substrate including a pixel region with multiple pixels arranged therein, the resulting structure can function as a radiation imaging panel. Therefore, when the substrate 101 does not include the pixel region 105, it may be a transparent substrate that transmits light emitted from the scintillator 108.

[0053] The following will refer to Figure 8 A radiation imaging apparatus incorporating the above-described radiation imaging panel 100 and a radiation imaging system 800 using the radiation imaging apparatus incorporating the radiation imaging panel 100 will be described.

[0054] The radiation imaging system 800 is configured to electrically capture an optical image formed by radiation, thereby obtaining an electrical radiation image (ie, radiation image data). The radiation imaging system 800 includes, for example, a radiation imaging device 801 , an exposure controller 802 , a radiation source 803 , and a computer 804 .

[0055] A radiation source 803 for emitting radiation toward the radiation imaging device 801 starts emitting radiation in accordance with an exposure command from the exposure controller 802. The radiation emitted from the radiation source 803 passes through a subject to be examined (not shown) and irradiates the radiation imaging device 801. The radiation source 803 stops emitting radiation in accordance with a stop command from the exposure controller 802.

[0056] The radiographic apparatus 801 includes the aforementioned radiographic panel 100, a controller 805 for controlling the radiographic panel 100, and a signal processor 806 for processing signals output from the radiographic panel 100. For example, the signal processor 806 can perform A / D conversion on the signal output from the radiographic panel 100 and output the signal as radiographic image data to the computer 804. As another example, the signal processor 806 can also generate a stop signal for stopping the emission of radiation from the radiation source 803 based on the signal output from the radiographic panel 100. This stop signal is supplied to the exposure controller 802 via the computer 804, and the exposure controller 802 transmits a stop command to the radiation source 803 in response to the stop signal.

[0057] The controller 805 may be a PLD (abbreviation of programmable logic device) such as FPGA (abbreviation of field programmable gate array), an ASIC (abbreviation of application specific integrated circuit), a general-purpose computer installed with a program, or a combination of all or part of these components.

[0058] In this embodiment, the signal processor 806 is arranged in the controller 805 or is shown as a function of the controller 805. However, the present invention is not limited to this. The controller 805 and the signal processor 806 may also be separate units. In addition, the signal processor 806 may also be arranged outside the radiation imaging device 801. For example, the computer 804 may have the function of the signal processor 806. Therefore, the signal processor 806 may also be included in the radiation imaging system 800 as a signal processing device for processing the signal output from the radiation imaging device 801.

[0059] The computer 804 can control the radiation imaging device 801 and the exposure controller 802, and can perform processing such as receiving radiation image data from the radiation imaging device 801 and displaying the data as a radiation image. The computer 804 can also function as an input unit through which a user inputs conditions for capturing radiation images.

[0060] For example, the exposure controller 802 includes an exposure switch, and when the user turns on the exposure switch, it transmits an exposure command to the radiation source 803 and a start notification instructing the start of radiation emission to the computer 804. The computer 804, having received the start notification, responds to the start notification by notifying the controller 805 of the radiation imaging device 801 to start emission of radiation. In response to the notification, the controller 805 causes the radiation imaging panel 100 to generate a signal corresponding to the incident radiation.

[0061] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A radiation imaging panel comprising: a substrate on which a plurality of pixels are arranged, each of the plurality of pixels including a photoelectric conversion element; a scintillator disposed on the substrate; as well as a protective layer arranged to cover the scintillator, The scintillator comprises a plurality of columnar crystals containing alkali metal halides. The protective layer includes a resin layer containing a resin to which metal oxide particles are added. The thickness of the resin layer from the apex of each of the plurality of columnar crystals to the upper surface of the resin layer is greater than or equal to 10 μm and less than 30 μm, and The particle concentration in the resin layer is greater than or equal to 0.15 vol % and less than 7.5 vol %.

2. The radiation imaging panel according to claim 1, wherein The average particle size of the particles is greater than or equal to 200 nm and less than or equal to 500 nm.

3. The radiation imaging panel according to claim 1, wherein The refractive index of the particles is greater than or equal to 1.94 and less than or equal to 2.

72.

4. The radiation imaging panel according to claim 1, wherein The particles contain at least one selected from the group consisting of white lead, zinc oxide, and titanium oxide.

5. The radiation imaging panel according to claim 1, wherein The particles contain rutile titanium dioxide.

6. The radiation imaging panel according to claim 1, wherein The refractive index of the resin is greater than or equal to 1.49 and less than or equal to 1.

53.

7. The radiation imaging panel according to claim 1, wherein The resin is made of a non-volatile thermoplastic material.

8. The radiation imaging panel according to claim 7, wherein The resin contains a hot-melt resin.

9. The radiation imaging panel according to claim 1, wherein The resin contains a resin having pressure-sensitive adhesiveness obtained by intermolecular force.

10. The radiation imaging panel according to claim 9, wherein The resin contains at least one selected from the group consisting of polyurethane resins and acrylic resins.

11. The radiation imaging panel according to claim 1, wherein The alkali metal halide contains cesium iodide.

12. The radiation imaging panel according to claim 1, wherein The protective layer further includes a base formed on a side of the resin layer opposite to the scintillator.

13. The radiation imaging panel according to claim 12, wherein The protective layer further includes a metal layer formed between the resin layer and the substrate.

14. A radiation imaging device comprising: The radiation imaging panel according to any one of claims 1 to 13; as well as A controller is configured to control the radiation imaging panel.

15. A radiation imaging system comprising: The radiation imaging device according to claim 14; as well as A signal processing device is configured to process a signal output from the radiation imaging device.

16. A scintillator sheet, comprising: substrate; a scintillator disposed on the substrate; as well as a protective layer arranged to cover the scintillator, The scintillator comprises a plurality of columnar crystals containing alkali metal halides. The protective layer includes a resin layer containing a resin to which metal oxide particles are added. The thickness of the resin layer from the apex of each of the plurality of columnar crystals to the upper surface of the resin layer is greater than or equal to 10 μm and less than 30 μm, and The particle concentration in the resin layer is greater than or equal to 0.15 vol % and less than 7.5 vol %. The scintillator sheet according to claim 16 , wherein: The substrate is a transparent substrate that transmits light generated by the scintillator.

Images