Scintillator panel, radiation detector using the same, linear array camera and radiation inspection apparatus, and on-line inspection method and inspection method using the same

Abstract

A high-brightness scintillator panel is provided that suppresses brightness degradation caused by radiation irradiation. The scintillator panel comprises a substrate and a scintillator layer containing a phosphor, wherein the scintillator layer includes an adhesive resin having a π-conjugated structure consisting of 7 or more atoms, the glass transition temperature of the adhesive resin is 30–430°C, and the film thickness of the scintillator layer is 50–800 μm.

Description

Technical Field

[0001] The present invention relates to a scintillator panel, a radiation detector using the scintillator panel, a line camera, a radiation inspection apparatus, and an online inspection method using the radiation inspection apparatus. Background Technology

[0002] Previously, membrane-based detection methods were widely used in fields requiring X-ray imaging. However, since membrane-based X-ray images are analog, digital radiation detection devices such as flat panel detectors (FPDs) have been developed in recent years.

[0003] In indirect conversion FPDs, a scintillator panel is used to convert X-rays into visible light. The scintillator panel has a scintillator layer containing phosphors such as gadolinium oxysulfide (GOS), which emits light when irradiated with X-rays. The light emitted from the scintillator panel is converted into an electrical signal using a sensor (photoelectric conversion layer) equipped with a thin-film transistor (TFT) and a charge-coupled device (CCD), thereby converting the X-ray information into digital image information.

[0004] For X-ray detectors used in radiation detection devices that utilize X-rays as radiation, high brightness is desirable. Furthermore, from a durability point of view, excellent adhesion between the scintillator panel and the support is desirable. Therefore, research was conducted on the phosphor particles contained in the scintillator layer and the adhesive resin (see, for example, Patent Documents 1-3).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-194580

[0008] Patent Document 2: Japanese Patent Application Publication No. 2019-23579

[0009] Patent Document 3: Japanese Patent Application Publication No. 2016-38324 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] In industrial applications, online inspection of food, electronic components, etc., requires a fast inspection time (cycle time) for each product. Furthermore, a method for achieving a fast cycle time is to perform inspection while continuously irradiating with X-rays. However, the technology described in Patent Documents 1-3 has the problem of reduced detector brightness during use due to continuous X-ray irradiation.

[0012] Furthermore, the inventors' research revealed that the aforementioned problems were caused by the use of adhesive resin within the scintillator layer under high-dose radiation exposure conditions, resulting in degradation (e.g., discoloration).

[0013] In view of the above-mentioned problems, the object of the present invention is to provide a high-brightness scintillator panel that suppresses brightness degradation caused by radiation irradiation.

[0014] Methods for solving problems

[0015] The present invention is a scintillator panel having a substrate and a scintillator layer containing phosphors. The scintillator layer contains an adhesive resin having a π-conjugated structure consisting of 7 or more atoms, and the glass transition temperature of the adhesive resin is 30 to 430°C. The film thickness of the scintillator layer is 50 to 800 μm.

[0016] The effects of the invention

[0017] According to the present invention, a scintillator panel with high brightness and excellent radiation resistance can be obtained. Attached Figure Description

[0018] Figure 1 A cross-sectional view is shown schematically of an X-ray detector comprising the scintillator panel of the present invention.

[0019] Figure 2 A cross-sectional view is shown schematically of an X-ray detector comprising a scintillator panel having scintillator layers divided by spacers. Detailed Implementation

[0020] Hereinafter, preferred configurations of scintillator panels and radiation detectors using the scintillator panels according to embodiments of the present invention will be described with appropriate reference to the accompanying drawings, but the present invention is not limited thereto.

[0021] The scintillator panel of the present invention has at least a substrate and a scintillator layer. The scintillator layer absorbs the energy of incident radiation such as X-rays and emits electromagnetic waves in the range of wavelength, for example, 300 nm to 800 nm, that is, light in the range from ultraviolet to infrared light centered on visible light.

[0022] The scintillator layer contains at least a phosphor and a binder resin with a π-conjugated structure consisting of seven or more atoms. The phosphor absorbs energy from radiation such as X-rays and emits light. The binder resin binds multiple phosphor particles, fixing their relative positions within the scintillator layer.

[0023] exist Figure 1 The diagram schematically illustrates one embodiment of an X-ray detector including a scintillator panel according to an embodiment of the present invention. The X-ray detector 1 includes a scintillator panel 2, an output substrate 3, and a power supply unit 12.

[0024] The scintillator panel 2 has a substrate 5 and a scintillator layer 4. The scintillator layer 4 contains a phosphor 6 and an adhesive resin 7.

[0025] The output substrate 3 has a photoelectric conversion layer 9 and an output layer 10 on the substrate 11. The photoelectric conversion layer 9 is generally a material in which pixels with light sensors (not shown) are formed, for example, a material in which pixels are arranged in a matrix facing the scintillator layer 4 within the photoelectric conversion layer. A diaphragm layer 8 may be provided on the photoelectric conversion layer 9. Preferably, the light-emitting surface of the scintillator panel 2 is bonded or sealed to the photoelectric conversion layer 9 of the output substrate 3 via the diaphragm layer 8.

[0026] exist Figure 2 The diagram schematically illustrates another embodiment of an X-ray detector 1 that includes the scintillator panel according to an embodiment of the present invention. The X-ray detector 1 includes a scintillator panel 2, an output substrate 3, and a power supply unit 12.

[0027] The scintillator panel 2 has a substrate 5 and a scintillator layer 4, which is divided by spacers 13. The scintillator layer 4 contains a phosphor 6 and an adhesive resin 7. The output substrate 3 has a photoelectric conversion layer 9 and an output layer 10 on a substrate 11. The photoelectric conversion layer 9 is generally a material in which pixels with light sensors (not shown) are formed. A diaphragm layer 8 may be provided on the photoelectric conversion layer 9. Light emitted in the scintillator layer 4 reaches the photoelectric conversion layer 9, is photoelectrically converted, and is output.

[0028] (Adhesive resin)

[0029] The binder resin contained in the scintillator layer has a π-conjugated structure consisting of seven or more atoms. This π-conjugated structure provides the binder resin with a resonantly stable structure, suppressing discoloration caused by radiation irradiation. Because discoloration caused by radiation irradiation is suppressed, even when the scintillator panel is used under high-dose radiation irradiation conditions, brightness reduction can be suppressed, enabling a long lifespan for the scintillator panel.

[0030] The term "π-conjugated structure" in adhesive resins refers to a state in which the resin structure alternates between single bonds and multiple bonds, with multiple multiple bonds existing in multiple states. The term "π-conjugated structure consisting of 7 or more atoms" refers to a structure that alternates between single bonds and multiple bonds, with multiple multiple bonds existing in multiple states, and in this structure, 7 or more atoms constituting the multiple bonds. For example, the number of atoms constituting the π-conjugated structure of an adhesive resin is 0 for polymethyl methacrylate, 6 for polystyrene, 10 for polyethylene terephthalate, 6 for polyhydroxystyrene, 6 for polycarbonate, and 14 for poly(4,4'-oxydiphenyl pyromellitictetramethylimide). A π-conjugated structure consisting of 7 or more atoms can be confirmed by calculating the number of atoms constituting the multiple bonds in a structure with alternating single bonds and multiple multiple bonds, after confirming the structure of the adhesive resin using the method described later.

[0031] The adhesive resin preferably has a π-conjugated structure consisting of 30 or fewer atoms. By having a π-conjugated structure consisting of 30 or fewer atoms, the absorption wavelength of the adhesive resin can be suppressed to be extended to a longer wavelength, thereby increasing the transmittance in the visible light region, reducing the initial coloration of the adhesive resin, and further improving the brightness.

[0032] The transmittance of the solution containing 2.5% by weight of the adhesive resin used in this invention at a wavelength of 400 nm and an optical path length of 1 cm is preferably 85% or more, more preferably 90% or more. By having a transmittance of 85% or more at a wavelength of 400 nm and an optical path length of 1 cm of the solution containing 2.5% by weight of the adhesive resin, the initial coloration of the adhesive resin is reduced. Therefore, the absorption of light emitted by the phosphor in the adhesive resin can be suppressed, the attenuation of light in the phosphor layer is reduced, and thus the brightness is further improved. The transmittance of the solution containing 2.5% by weight of the adhesive resin at a wavelength of 400 nm and an optical path length of 1 cm is a value measured using a UV-Vis spectrophotometer (e.g., Hitachi Hightech U-4100). There is no particular limitation as long as the solvent in the solution uniformly dissolves the adhesive resin, and the transmittance of the solvent alone at a wavelength of 400 nm and an optical path length of 1 cm is 80% or more.

[0033] The adhesive resin used in this invention preferably has a repeating unit in the main chain as shown in the following general formula (1) or general formula (2).

[0034]

[0035]

[0036] In the above general formulas (1) and (2), X 1 X 2 Y1 and Y 2 Each of these represents a divalent organic group independently. Ar represents an aromatic hydrocarbon group. t represents an integer of 1 or 2.

[0037] Since Ar is an aromatic hydrocarbon group, the Ar-C (=O) portion in general formulas (1) and (2) is a structure capable of resonance stabilization. The aromatic hydrocarbon group can be substituted or unsubstituted. Preferred substituents in the case of substitution include aliphatic hydrocarbon groups, carboxyl groups, amino groups, hydroxyl groups, alkoxy groups, halogens, and silyl groups. The aromatic hydrocarbon group is preferably an aromatic hydrocarbon group with 6 to 25 carbon atoms including the substituent.

[0038] Specific examples of aromatic hydrocarbon groups include, for example, phenylene, naphthylene, anthraceneylene, and phenanthrene. Two or more of these groups may be present. Among them, from the viewpoint of resin solvent solubility, transparency, and color tone, phenylene or naphthylene is preferred, and phenylene is particularly preferred. Specific examples of Ar are divalent groups derived from these groups in general formula (1) and trivalent to tetravalent groups derived from these groups in general formula (2).

[0039] In general formula (1), X 1 It is a divalent organic group. Preferably, it is a substituted or unsubstituted hydrocarbon group, a substituted or unsubstituted organic group derived from a diol, a substituted or unsubstituted organic group derived from a diamine, or a group composed of two or more of these.

[0040] Examples of hydrocarbon groups include aliphatic hydrocarbon groups and aromatic hydrocarbon groups. Aliphatic hydrocarbon groups can be straight-chain or branched, and can be partially or entirely cyclic. Furthermore, they can be saturated or unsaturated hydrocarbon groups. In aliphatic hydrocarbon groups, at least a portion of the hydrogen atoms can be replaced by halogens or the like. In aromatic hydrocarbon groups, at least a portion of the hydrogen atoms can be replaced by halogens or the like. The number of carbon atoms in the hydrocarbon group is preferably 2 or more, more preferably 4 or more. The number of carbon atoms in the hydrocarbon group is preferably 25 or less, more preferably 20 or less.

[0041] The organic groups derived from diols refer to residues formed by removing hydrogen atoms from the two hydroxyl groups of a diol. Examples of diols include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylenediol, tetramethylenediol, 1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 2,2-isopropyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, neopentyl glycol, hexanediol, 1,4-cyclohexanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and other aliphatic diols, as well as aromatic diols such as bisphenol A. A product may contain two or more of these diols.

[0042] The term "organic group derived from diamine" refers to a residue formed by removing one hydrogen atom from each of the two amino groups of a diamine. Examples of diamines include 1,6-hexanediamine, 2-methyl-1,5-diaminopentane, 2,2,4-trimethylhexanediamine, 2,4,4-trimethylhexanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,12-decanediamine, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylpropane, and 4,4'-di... Amino-3,3'-dimethyldicyclohexylmethane, 1,4-diaminocyclohexane, 1,4-bis(aminomethyl)-cyclohexane, 2,6-bis(aminomethyl)-norbornene, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, bis-(4-amino-3-methyl-cyclohexyl)methane, isophorone diamine and other aliphatic diamines, m-phenylenediamine, p-phenylenediamine, bis(4-aminophenyl)propane and other aromatic diamines, etc. It may contain two or more of these.

[0043] In general formula (1), Y 1 It is a divalent organic group. Preferably, it is a group composed of, for example, substituted or unsubstituted hydrocarbon groups, ether groups, thioether groups, carbonyl groups, sulfonyl groups, imino groups, and combinations thereof. Among these, from the viewpoint of inhibiting discoloration and deterioration of the resin caused by radiation irradiation and the ease of synthesis, substituted or unsubstituted hydrocarbon groups, ether groups, carbonyl groups, and combinations thereof are preferred. Examples of substituents for hydrocarbon groups include, for example, halogens. In Y 1 When the hydrocarbon group is a hydrocarbon group, the number of carbon atoms in the hydrocarbon group is preferably 1 or more, more preferably 3 or more. The number of carbon atoms in the hydrocarbon group is preferably 15 or less, more preferably 10 or less.

[0044] Specific examples of adhesive resins having a main chain structure as shown in general formula (1) include, for example, polyester resins (e.g., X...). 1 Y is an organic group derived from diol. 1 (for carbonyl groups), polyetheretherketone resins (e.g., X) 1 It is a hydrocarbon group, Y 1 (The case where the group is a combination of an ether group and a hydrocarbon group), polyamide resin (e.g., X) 1 Y is an organic group derived from diamine. 1 (For the case of carbonyl groups), etc.

[0045] In general formula (2), X 2 It is a divalent organic group. As a divalent organic group, it is preferably, for example, a group composed of a substituted or unsubstituted hydrocarbon group, or a group composed of a substituted or unsubstituted hydrocarbon group and one or more groups selected from ether group, thioether group, ester group, carbonyl group, sulfonyl group, imino group and amide group.

[0046] Among them, preferred are substituted or unsubstituted hydrocarbon groups, and groups formed by combining substituted or unsubstituted hydrocarbon groups with ether groups and / or sulfonyl groups. Specific examples include, for instance, structures as described below.

[0047]

[0048] In general formula (2), Y 2 It is a divalent organic group. Preferably, it is a group composed of, for example, substituted or unsubstituted hydrocarbon groups, ether groups, thioether groups, ester groups, carbonyl groups, sulfonyl groups, imino groups, amide groups, imide groups, and combinations thereof. From the viewpoint of inhibiting discoloration and deterioration of resins caused by radiation irradiation, it is preferred to be a group composed of substituted or unsubstituted hydrocarbon groups, ether groups, ester groups, sulfonyl groups, carbonyl groups, amide groups, imide groups, and combinations thereof. The number of carbon atoms in the hydrocarbon group is preferably 1 to 8. In the case where t is 2 in general formula (2), multiple Y... 2 They can be the same or different. Furthermore, multiple Ys... 2 It can form a ring structure.

[0049] Specific examples of adhesive resins having a main chain structure as shown in general formula (2) include, for example, polyimide resins (e.g., Y... 2 (for imide groups), polyetherimide resins (e.g., Y...) 2 (The case where the group is a combination of an ether group, a hydrocarbon group, and an imide group), polyamide-imide resin (e.g., Y...) 2 (In cases containing amide groups), etc.

[0050] The structure of the resin shown in general formulas (1) to (2) can be confirmed by using nuclear magnetic resonance (NMR) to assign the detected peaks.

[0051] The adhesive resin used in this invention is preferably amorphous. Because the adhesive resin is amorphous, its solvent solubility is good, allowing for uniform mixing of the phosphor and adhesive resin in the scintillator panel manufacturing method described later, thus forming a uniform phosphor layer. As a result, localized brightness degradation of the scintillator panel caused by coloration of the adhesive resin can be suppressed. Furthermore, compared to resins requiring heat melting, such as hot-melt resins, the high-temperature heating process in the scintillator panel manufacturing process is unnecessary, making substrate selection easier and reducing degradation such as discoloration of the adhesive resin during high-temperature heating. Consequently, the brightness of the scintillator panel is further improved. Here, "amorphous" refers to the situation where, when the adhesive resin is measured by powder X-ray diffraction, no peaks originating from the crystal structure are observed, only broad halos.

[0052] The adhesive resin used in this invention has a glass transition temperature of 30–430°C. The lower limit of the glass transition temperature is 30°C, preferably 40°C or higher. If the glass transition temperature of the adhesive resin is 30°C or higher, the generation of free radicals in the adhesive resin caused by radiation irradiation, as well as the associated intermolecular cross-linking, breakage, and decomposition, can be reduced. Therefore, coloration and structural changes in the adhesive resin caused by reactions at the breakage sites with other molecules can be suppressed. Consequently, the brightness degradation of the scintillator panel caused by coloration of the adhesive resin and the deformation of the scintillator panel accompanying the reduction in the mechanical properties of the adhesive resin can be suppressed.

[0053] On the other hand, the upper limit of the glass transition temperature of the adhesive resin is 430°C, more preferably 270°C or lower, and even more preferably 260°C or lower. If the glass transition temperature is higher than 430°C, the adhesive resin is also prone to staining and its brightness decreases before X-ray irradiation.

[0054] In this invention, the glass transition temperature of the adhesive resin is a value determined using a differential thermal analysis device (e.g., a differential thermal balance TG8120; manufactured by Rigaku Corporation).

[0055] In this invention, the weight-average molecular weight (Mw) of the binder resin is preferably in the range of 5,000 to 100,000. If the weight-average molecular weight (Mw) of the binder resin is 5,000 or higher, the binder resin provides sufficient strength to hold the phosphor, suppressing defects, cracks, and brightness reduction in the scintillator layer. Furthermore, it is less susceptible to changes in molecular structure caused by radiation irradiation, suppressing discoloration of the scintillator panel and deterioration of its mechanical properties. If the Mw of the binder resin is 100,000 or lower, high-density phosphor particle filling is possible, resulting in increased brightness.

[0056] The dispersion (Mw / Mn) obtained by dividing the weight-average molecular weight (Mw) of the adhesive resin by the number-average molecular weight (Mn) is preferably 1.5 to 5.0. If the dispersion of the adhesive resin is 1.5 or higher, the manufacturing yield of the adhesive resin can be improved. If the dispersion of the adhesive resin is 5.0 or lower, the generation of poorly soluble components in the solvent can be suppressed, and the deviation in brightness in the scintillator layer can be suppressed.

[0057] Here, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the adhesive resin are molecular weights determined and calculated by gel permeation chromatography (GPC), based on conversion values ​​of polystyrene samples with known molecular weights. Specifically, they can be determined using gel permeation chromatography GPC (GPC-22) / differential refractive index detector RI (manufactured by Higashi Soy Co., Ltd., RI-8020 type), and can be calculated by measuring monodisperse polystyrene (manufactured by Higashi Soy Co., Ltd.) as a standard substance.

[0058] The energy difference Eg between the highest occupied molecular orbital and the lowest unoccupied molecular orbital in the adhesive resin used in this invention is preferably 2.0 eV or more and 4.2 eV or less, more preferably 2.7 eV or more and 4.1 eV or less. If the Eg of the adhesive resin is 2.0 eV or more, the absorption of light emitted by the phosphor in the adhesive resin can be suppressed, the attenuation of light in the phosphor layer is reduced, and thus the brightness is further improved. Since the Eg of the adhesive resin is 4.2 eV or less, the energy released when electrons in the radioactively excited adhesive resin return to the ground state is equal to or lower than the average binding energy between the atoms constituting the adhesive resin, thus reducing the probability of dissociation of the bonds between the atoms of the adhesive resin. As a result, the probability of free radical generation in the adhesive resin is reduced, and / or the reactivity of the generated free radicals is reduced, thus suppressing the coloration of the adhesive resin caused by free radical reactions, and further suppressing brightness degradation.

[0059] In this invention, the Eg of the adhesive resin is a value calculated using a Tauc plot. Specifically, the optical constants (refractive index n, extinction coefficient k) for each wavelength are determined using a spectroscopic ellipsometry (e.g., FE-5000; manufactured by Otsuka Electronics Co., Ltd.), and the absorption coefficient α is calculated from the extinction coefficient k. The energy E of each wavelength is set as the x-axis, and (Eα) is... 2 Plot the Tauc plots separately, using the y-axis as the axis. From the resulting S-shaped ascending curve, derive the tangent line passing through the inflection point; the intersection of this tangent line with the x-axis is then used as Eg. It should be noted that if a baseline exists in the Tauc plot besides the x-axis, the intersection of the tangent line with that baseline is called Eg.

[0060] Within the scintillator layer, adhesive resins other than those described above may be included, without impairing the effects of the present invention. Examples of such adhesive resins include, for instance, acrylic resins, cellulose resins, epoxy resins, melamine resins, phenolic resins, urea resins, vinyl chloride resins, butyral resins, polyvinyl acetal, silicone resins, polyester resins, polyamide resins, polyimide resins, polyamide-imide resins, polycarbonate resins, polyketide resins, polyether resins, polyethylene, polypropylene, polycarbonate, polystyrene, polyvinyltoluene, polyvinylpyrrolidone, polyacrylamide, polyvinyl acetate, aromatic hydrocarbon resins, polyalkylene polyamine resins, polybenzimidazole resins, polypyrrole resins, and polythiophene resins.

[0061] (Fluorescent material)

[0062] The phosphor used in the scintillator panel of the present invention can be any material that emits light in the range of ultraviolet to infrared light centered on visible light when irradiated by radiation. For example, it can be any of inorganic phosphors or organic phosphors.

[0063] Examples of inorganic phosphors include sulfide-based phosphors, germanate-based phosphors, halide-based phosphors, barium sulfate-based phosphors, hafnium phosphate-based phosphors, tantalate-based phosphors, tungstate-based phosphors, rare earth silicate-based phosphors, rare earth oxysulfide-based phosphors, rare earth phosphate-based phosphors, rare earth oxyhalide-based phosphors, alkaline earth metal phosphate-based phosphors, and alkaline earth metal fluoride halide-based phosphors.

[0064] Examples of rare earth silicate phosphors include cerium-activated rare earth silicate phosphors; examples of rare earth oxysulfide phosphors include praseodymium-activated rare earth oxysulfide phosphors, terbium-activated rare earth oxysulfide phosphors, and europium-activated rare earth oxysulfide phosphors; examples of rare earth phosphate phosphors include terbium-activated rare earth phosphate phosphors; examples of rare earth oxyhalide phosphors include terbium-activated rare earth oxyhalide phosphors and thulium-activated rare earth oxyhalide phosphors; examples of alkaline earth metal phosphate phosphors include europium-activated alkaline earth metal phosphate phosphors; and examples of alkaline earth metal fluoride halide phosphors include europium-activated alkaline earth metal fluoride halide phosphors.

[0065] Examples of organic fluorescent agents include p-terphenyl, p-tetraphenyl, and 2,5-diphenyl. Zyrazole, 2,5-diphenyl-1,3,4-oxodiazole, naphthalene, diphenylacetylene, zirconia, etc.

[0066] It may contain two or more of them. Among them, phosphors selected from rare earth oxysulfide phosphors are preferred. Considering luminescence efficiency and chemical stability, gadolinium oxysulfide is preferred among rare earth oxysulfides. Gadolinium oxysulfide is preferably a substance that has undergone terbium activation, europium activation, or praseodymium activation.

[0067] Examples of phosphor shapes include particle-shaped, columnar, and scaly shapes. Among these, particle-shaped phosphors are preferred. By making the phosphor particle-shaped, the phosphor is more uniformly dispersed in the scintillator layer, thereby suppressing the luminescence bias of the phosphor in the scintillator layer and making it emit light uniformly.

[0068] The average particle size of the phosphor is preferably 0.5–50 μm, more preferably 3.0–40 μm, and even more preferably 4.0–30 μm. If the average particle size of the phosphor is 0.5 μm or more, the conversion efficiency from radiation to visible light is further improved, resulting in increased brightness. Furthermore, phosphor aggregation can be suppressed. On the other hand, if the average particle size of the phosphor is 50 μm or less, the surface smoothness of the scintillator layer is excellent, suppressing the generation of bright spots in the image.

[0069] Here, the so-called average particle size of the phosphor in this invention refers to the particle size that accounts for 50% of the cumulative particle size distribution, which can be measured using a particle size distribution measuring device (e.g., MT3300; manufactured by Nikkiso Co., Ltd.). More specifically, the phosphor is placed in a water-filled sample chamber, subjected to ultrasonic treatment for 300 seconds, and the particle size distribution is measured. The particle size that accounts for 50% of the cumulative distribution is set as the average particle size.

[0070] The time required for the phosphor's luminescence intensity to reach 1 / e times the initial luminescence intensity is preferably 100 μs or less. If the time required to reach 1 / e times is 100 μs or less, in the continuous imaging method of the subject including the online inspection described later, it is possible to suppress the X-ray image of each subject from remaining in the image of subsequent subjects. As a result, continuous inspection can be performed at high speed. The decay time of the phosphor's luminescence intensity can be measured by known methods. Specifically, methods using ultraviolet light as excitation light using a fluorescence lifetime measuring device (e.g., Quantaurus-Tau C11367-24; Hamamatsu Hotniks Co., Ltd.) and methods using radiation as excitation source using a device consisting of an optical fiber, a photodiode, and a photodetector amplifier can be cited. As a method to shorten the decay time of the phosphor's luminescence intensity, gadolinium oxysulfide can be used as an example, and methods using a substance different from terbium as the activator can be cited, particularly by activation with praseodymium, thereby shortening the decay time.

[0071] The preferred volume ratio of phosphor to binder resin in the scintillator layer is phosphor: binder resin = 80:20 to 95:5. By making the phosphor volume ratio 80% or more, the content of binder resin that changes color upon radiation irradiation is reduced, which suppresses the attenuation of light emitted within the scintillator layer, thus improving brightness. A more preferred phosphor: binder resin volume ratio is phosphor: binder resin = 83:17 to 95:5, and even more preferred is phosphor: binder resin = 85:15 to 95:5. On the other hand, by making the phosphor volume ratio 95% or less, the binding force between phosphor particles provided by the binder resin can be maintained after radiation irradiation, thus suppressing defects and cracks in the scintillator layer and further improving the adhesion strength between the substrate and the scintillator layer. Furthermore, it improves the dispersion of phosphor during scintillator layer formation, suppressing brightness deviations within the scintillator layer.

[0072] (Other elements of the scintillator layer)

[0073] A dispersant may be included in the scintillator layer. By including a dispersant, the aggregation and sedimentation of phosphor particles in the phosphor paste (described later) can be suppressed, resulting in a longer shelf life. Furthermore, since a uniform dispersion of phosphor particles in the phosphor paste can be maintained, bias in the distribution of phosphor particles in the scintillator layer can be suppressed, thus suppressing brightness deviations in the scintillator layer. As a dispersant, a substance having anionic functional groups is preferred, and substances having carboxyl, sulfonic acid, and / or phosphate groups are even more preferred.

[0074] The scintillator layer may further include dispersants, plasticizers, crosslinking agents, surface conditioners, antistatic agents, metal compound particles, etc.

[0075] To increase the number of luminescent phosphors and thus improve brightness, a thicker scintillator layer is preferable. This thickness can be appropriately set based on the X-ray quality, but in this invention it is 50–800 μm, more preferably 70–600 μm, and even more preferably 100–400 μm. If the film thickness is 50 μm or more, the phosphor particle size relative to the film thickness can be selected to mitigate the effect of discoloration of the adhesive resin caused by radiation irradiation, without impairing the effectiveness of this invention, thus suppressing a decrease in brightness. If the film thickness is 800 μm or less, the optical path length of light emitted in the scintillator layer, especially light emitted on the substrate side, is short up to the photoelectric conversion layer, thus reducing the effect of discoloration of the adhesive resin caused by radiation irradiation. As a result, light attenuation in the scintillator layer can be reduced, suppressing a decrease in brightness. Furthermore, since the degradation of mechanical properties caused by radiation irradiation can be suppressed, the decrease in the adhesion between phosphors and the bonding strength between the substrate and the scintillator layer caused by the adhesive resin can be suppressed. If it falls within the above range, the film thickness uniformity is also excellent, and the influence of brightness deviation caused by the unevenness of the scintillator layer surface is reduced relative to the film thickness.

[0076] When the scintillator layer is a stacked structure with two or more layers, the relationship between the thickness Td of the scintillator layer (lower scintillator layer) on the substrate side and the thickness Tt of the scintillator layer (upper scintillator layer) stacked thereon is preferably in the range of 0.4 to 0.9, more preferably in the range of 0.6 to 0.9.

[0077] The brightness L of the scintillator panel of the present invention ＊ Preferably 75 or higher, more preferably 80 or higher. (Based on lightness L) ＊ With a value of 75 or higher, the light emitted in the phosphor can be suppressed from attenuating in the scintillator layer, thus further improving the brightness.

[0078] The chromaticity a of the scintillator panel of the present invention ＊ Preferably -10.0 to 10.0, more preferably -6.0 to 6.0. This is determined by chromaticity a. ＊ The range is -10.0 to 10.0, which can suppress the light emitted in the phosphor. In particular, the longer wavelength light attenuates in the scintillator layer compared to the area around 450 nm, resulting in a greater increase in brightness.

[0079] The chromaticity b of the scintillator panel of the present invention ＊ Preferably -15.0 to 15.0, more preferably -10.0 to 10.0, and even more preferably -6.0 to 6.0. This is determined by chromaticity b. ＊ The wavelength range is -15.0 to 15.0, which can suppress the light emitted in the phosphor. In particular, the shorter wavelength light attenuates in the scintillator layer compared to the wavelength around 600 nm, resulting in a greater increase in brightness.

[0080] (Substrate)

[0081] The material used as the substrate for the scintillator panel of the present invention is preferably a substance with high radiometric transmittance, and examples include various glasses, polymers, and metals. Examples of glasses include quartz, borosilicate glass, and chemically strengthened glass. Examples of polymers include polyesters such as cellulose acetate and polyethylene terephthalate (PET), polyamides, polyimides, triacetate, polycarbonate, and carbon fiber reinforced resins. Examples of metals include aluminum, iron, and copper. Two or more of these materials can be used. Among them, polymers with high radiometric transmittance are particularly preferred. Furthermore, materials with excellent flatness and heat resistance are preferred.

[0082] From the viewpoint of lightweighting the scintillator panel, for example, when using a glass substrate, the thickness of the substrate is preferably 2.0 mm or less, more preferably 1.0 mm or less, and even more preferably 0.5 mm or less. Furthermore, when the substrate is formed of a polymer material, it is preferably 3.0 mm or less, more preferably 1.0 mm or less. The thickness of the substrate in this invention can be calculated by cutting out a cross-section of the substrate using a slicing machine, observing 10 points using a scanning electron microscope (e.g., a field emission scanning electron microscope "S-4800" manufactured by Hitachi, Ltd.), and measuring the average thickness.

[0083] The substrate can have a metal layer on its surface next to the scintillator layer. With a metal layer on the substrate, high reflectivity can be achieved regardless of the substrate's color tone or thickness. The metal layer can be formed on the substrate using known methods; specifically, layers of aluminum, silver, and their alloys can be formed on the substrate surface using methods such as physical vapor deposition (PVD) and chemical vapor deposition (CVD).

[0084] When using polymeric materials as the base material, polyester is preferred as the main component from the viewpoints of reflectivity, strength, and heat resistance. Here, the term "main component" in this invention refers to a component of 50% by mass or more. More preferably, white polyester, which is a main component and further comprises materials with different refractive indices, is preferred.

[0085] Polyesters are polymers of diols and dicarboxylic acids. Examples of diols include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, 1,6-hexanediol, trimethylene glycol, and tetramethylenediol. Examples of dicarboxylic acids include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenylacetic acid, adipic acid, and sebacic acid. Examples of polyesters include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene p-hydroxybenzoate, polyethylene terephthalate-1,4-cyclohexanediol, and polyethylene 2,6-naphthalenedicarboxylic acid (PEN).

[0086] Examples of materials with different refractive indices include white pigments such as zinc oxide, zirconium oxide, titanium oxide, gadolinium oxide, gadolinium oxysulfide, and high-refractive-index glass ceramic particles.

[0087] Since the substrate preferably has high radiometric transmittance, it is preferable not to contain elements from period 6 or higher of the periodic table, and more preferably not to contain elements from period 5 or higher. In particular, a substrate composed of elements from period 4 or lower is suitable because it has high radiometric transmittance. It should be noted that, in this invention, "not containing high-period elements" means that the content of high-period elements in the substrate is less than 0.1% by mass.

[0088] From the viewpoint of lightweight scintillator panels and low radiation transmittance, a low specific gravity is preferred for the substrate. Specifically, the specific gravity of the substrate is preferably 1.2 g / cm³. 3 The preferred value is 0.9 g / cm³. 3 The following is a further preferred value: 0.7 g / cm³ 3 Below. On the other hand, from the viewpoint of further suppressing cracking and wrinkling during substrate manufacturing and improving operability, the specific gravity of the substrate is preferably 0.5 g / cm³. 3 above.

[0089] The substrate preferably has an easy-adhesion layer on the surface of the phosphor layer side. By having an easy-adhesion layer, the adhesion strength between the scintillator layer and the substrate can be further improved.

[0090] Examples of materials that can be used as the easy-to-adhere layer include acrylic resins, epoxy resins, polyurethane resins, and polyester resins. Two or more of these may be included. Polyester resin is preferred as the main component. Polyester resin with a glass transition temperature of 10–80°C is more preferred. For example, when using PET as the substrate, an aromatic polyester with residues of terephthalic acid, isophthalic acid, etc., having a structure similar to PET, is preferred. As an aromatic polyester, a saturated copolyester with a weight-average molecular weight of 2,000–30,000 is preferred, and a non-crystalline solvent-soluble saturated copolyester with a weight-average molecular weight of 2,000–30,000 is more preferred. For a non-crystalline solvent-soluble saturated copolyester with a weight-average molecular weight of 2,000–30,000, a non-crystalline solvent-soluble type such as "Nichigo Polyester" (registered trademark) manufactured by Nippon Synthetic Chemicals Co., Ltd. is suitable. The glass transition temperature of the resin can be determined using a differential thermal analysis device (e.g., a differential thermal balance TG8120; manufactured by Rigaku Corporation).

[0091] The easy-to-bond layer may contain powder having a different refractive index than the polyester resin, which is the main component. By containing powder, light diffusion in the direction parallel to the support can be further suppressed. The refractive index difference Δn between the polyester and the powder is preferably 0.2 or more. As the powder, from the viewpoint of the refractive index difference with the resin, which is the main component of the easy-to-bond layer, an inorganic powder is preferred. Examples of inorganic powders used in the above-mentioned surface layer are examples of such powders. Titanium oxide powder is particularly preferred from the viewpoint of high refractive index. Here, the refractive index of the polyester resin can be measured using a refractometer (Abbe refractometer 4T; manufactured by Atago Co., Ltd., light source: sodium D-rays, measurement temperature 25°C) to obtain a resin film obtained by coating / drying a solution of polyester resin dissolved in a soluble organic solvent such as methyl ethyl ketone. Furthermore, the refractive index of inorganic powders has been published in publications such as "Inorganic Chemical Handbook" (Gihodo), "Filler Application Dictionary" (Taiseisha), and "Ceramic Engineering Handbook" (Japan Ceramic Society).

[0092] The substrate may have an adhesive layer and a support on the side opposite to where the scintillator layer exists. By having a support, the substrate becomes more rigid during the fabrication process of the scintillator panel, as described later, thus preventing breakage of the substrate during operation.

[0093] The material constituting the support preferably has high radiation transmittance. Examples of materials include cellulose acetate, polyester, polyamide, polyimide, triacetate, polycarbonate, and carbon fiber reinforced resins containing these and carbon fibers. The material constituting the support can be the same as the substrate.

[0094] Examples of materials constituting the adhesive layer include acrylic resins, epoxy resins, polyurethane resins, and polyester resins. Among these, considering the ability to bond at low temperatures, it is preferable to process acrylic adhesive materials, etc., into sheet-like optically clear adhesive sheets (OCA).

[0095] (Spacing)

[0096] The scintillator panel of the present invention preferably has spacers that divide the scintillator layers.

[0097] The material constituting the spacer is preferably a substance capable of forming a spacer with high strength and heat resistance, and is preferably, for example, an inorganic material or a polymeric material. Here, the term "inorganic material" in this invention refers to a compound composed of a portion of pure carbon compounds (such as graphite or diamond, allotropes of carbon) and elements other than carbon. It should be noted that "formed from inorganic matter" does not strictly exclude the presence of components other than inorganic matter, but rather allows for the presence of components other than inorganic matter, including impurities inherent in the inorganic matter itself and impurities introduced during the manufacturing process of the spacer.

[0098] When the spacer is formed of inorganic material, glass is preferably used as the main component. Glass refers to an inorganic amorphous solid containing silicates. If the main component of the spacer is glass, the strength, durability, and heat resistance of the spacer are improved, and deformation and damage are less likely to occur in the subsequent processes of forming the reflective layer and filling the phosphor. It should be noted that, in the embodiments of the present invention, "using glass as the main component" means that 50-100% by mass of the material constituting the spacer is glass.

[0099] In particular, regarding the spacer wall, when the volume of the spacer wall portion is set to 100% by volume, the proportion of low-softening-point glass (glass with a softening point of 650°C or below) is preferably 95% by volume or more, more preferably 98% by volume or more. By having a low-softening-point glass content of 95% by volume or more, the surface of the spacer wall is easily planarized during the firing process. This allows for the uniform formation of a reflective layer on the surface of the spacer wall in the scintillator panel. As a result, the reflectivity increases, further improving brightness.

[0100] Examples of components that can be used other than low-softening-point glass include high-softening-point glass powder and ceramic powder, which are glass with a softening point exceeding 650°C. These powders facilitate the adjustment of the spacer shape during the spacer formation process. To increase the content of low-softening-point glass, the content of components other than low-softening-point glass is preferably less than 5% by volume.

[0101] When the spacer is formed of a polymer material, it is preferably selected from polyimide, polyamide, polyamide-imide, and polybenzo[a]ethylene]ethylene. One or more compounds (P) from azole and acrylic resins are formed. By forming spacers from compound (P), fine, high aspect ratio, and smooth-surfaced spacers can be formed. When preparing a photosensitive resin composition using compound (P), the composition of the photosensitive material is not particularly limited. Examples include a photoradical polymerization negative photosensitive resin composition in which a multifunctional acrylic monomer and a photoradical polymerization initiator are added to compound (P); a photocationic polymerization negative photosensitive resin composition in which an epoxy compound and a photocationic polymerization initiator are added to compound (P); and a photosolubilizing positive photosensitive resin composition in which a naphthoquinone-based photosensitizer is added to compound (P). Among these, from the viewpoint of forming spacers with a high aspect ratio, a photocationic polymerization negative photosensitive resin composition containing an epoxy compound is preferred.

[0102] When the spacer wall is formed of compound (P), it preferably has phenolic hydroxyl groups. By having phenolic hydroxyl groups, moderate solubility of the resin in alkaline developer is obtained, thus achieving high contrast between the exposed and unexposed areas, and forming the desired pattern.

[0103] The spacers preferably further contain an epoxy compound. The epoxy compound does not impair the heat resistance and mechanical strength of compound (P), and can further improve processability, thus facilitating the formation of spacers of the desired shape. This allows for a greater filling amount of phosphor, resulting in improved brightness.

[0104] To avoid impairing the properties of compound (P), the content of the epoxy compound in the spacer wall is preferably no more than the content of compound (P) by mass fraction. If the spacer wall contains components other than compound (P) and the epoxy compound, their combined content, by mass fraction, is preferably no more than the combined content of compound (P) and the epoxy compound.

[0105] As an epoxy compound, known substances can be used, including aromatic epoxy compounds, alicyclic epoxy compounds, and aliphatic epoxy compounds.

[0106] (Reflective layer)

[0107] Preferably, a reflective layer, particularly a metallic reflective layer, is provided on the surface of the substrate of the spacer wall and the scintillator panel. By having a reflective layer, light emitted within the cells divided by the spacer wall through radiation irradiation can efficiently reach the detector side, thus easily improving brightness.

[0108] The material constituting the reflective layer is not particularly limited as long as it has the function of reflecting electromagnetic waves emitted from the phosphor. Examples include metal oxides such as titanium oxide and aluminum oxide, and metals such as silver and aluminum. Two or more of these materials may be included.

[0109] The material constituting the reflective layer is preferably a substance with high reflectivity even when it is a thin film. By using a thin film, the reduction of the internal volume of the cell can be suppressed, allowing for a larger amount of phosphor to be filled, thus making it easier to improve the brightness of the scintillator panel. Therefore, the reflective layer is preferably formed of metal, more preferably silver, aluminum, and alloys thereof. From the viewpoint of atmospheric discoloration resistance, a silver alloy containing palladium and copper is preferred.

[0110] The thickness of the reflective layer can be appropriately set according to the necessary reflective characteristics and is not particularly limited. For example, the thickness of the reflective layer is preferably 10 nm or more, more preferably 50 nm or more. Furthermore, the thickness of the reflective layer is preferably 500 nm or less, more preferably 300 nm or less. By providing a reflective layer with a thickness of 10 nm or more on the spacer wall, the scintillator panel suppresses light leakage through the spacer wall and obtains sufficient light shielding, resulting in improved clarity. By providing a reflective layer with a thickness of 500 nm or less, the surface unevenness of the reflective layer is less likely to increase, and the reflectivity is less likely to decrease.

[0111] The reflective layer preferably has a protective layer on its surface. Even when using alloys or other materials that lack resistance to discoloration in the atmosphere, the reflective layer can reduce discoloration and suppress the decrease in reflectivity of the metal reflective layer caused by the reaction between the metal reflective layer and the scintillator layer, thereby improving brightness.

[0112] (protective layer)

[0113] Regarding protective layers, both inorganic and organic protective layers are suitable for use. Inorganic and organic protective layers can also be stacked and used together as protective layers.

[0114] Inorganic protective layers are suitable as protective layers due to their low water vapor permeability. They can be formed using known methods such as sputtering. The material of the inorganic protective layer is not particularly limited. Examples of materials for inorganic protective layers include oxides such as silicon oxide, indium tin oxide, and zinc gallium oxide; nitrides such as silicon nitride; and fluorides such as magnesium fluoride. Among these, silicon nitride is preferred due to its low water vapor permeability and the fact that the reflectivity of silver is not easily reduced during the formation of the inorganic protective layer.

[0115] The thickness of the inorganic protective layer is not particularly limited. For example, a thickness of 2 nm or more is preferred, and more preferably 5 nm or more. Furthermore, a thickness of 300 nm or less is preferred, and more preferably 100 nm or less. A thickness of 2 nm or more allows for greater suppression of brightness reduction in the scintillator panel under operating conditions. A thickness of 300 nm or less allows for suppression of coloration caused by the inorganic protective layer, resulting in further improved brightness. The thickness of the inorganic protective layer can be measured using the same method as for the thickness of the organic protective layer, as described later.

[0116] The organic protective layer is preferably a polymer compound with excellent chemical durability, for example, preferably containing polysiloxane or amorphous fluororesin as the main component. Here, "amorphous fluororesin" refers to a situation where, when the fluorinated resin is measured by powder X-ray diffraction, no peaks originating from the crystal structure are observed, but only broad halos are observed.

[0117] Organic protective layers can be easily formed using known methods such as solution coating and spray coating.

[0118] The thickness of the organic protective layer is preferably 0.05 μm or more, more preferably 0.2 μm or more. Furthermore, the thickness of the organic protective layer is preferably 10 μm or less, more preferably 5 μm or less. By having an organic protective layer thickness of 0.05 μm or more, the suppression effect on the brightness reduction of the scintillator panel 2 can be greater. Furthermore, by having an organic protective layer thickness of 10 μm or less, the volume within the unit of the scintillator panel is larger, allowing for a sufficient amount of phosphor to be filled, thereby further improving the brightness. In embodiments of the present invention, the thickness of the organic protective layer can be measured by observation using a scanning electron microscope. It should be noted that the organic protective layer formed by the organic protective layer formation process described later tends to be thinner on the side near the top of the spacer wall and thicker on the side near the bottom. Therefore, in cases where there is such a thickness difference, the aforementioned thickness of the organic protective layer refers to the thickness on the central side of the spacer wall in the height direction.

[0119] (Manufacturing method of scintillator panel)

[0120] In this invention, a method for manufacturing a scintillator panel may include, for example, coating a substrate with a phosphor paste containing a phosphor, an adhesive resin having a π-conjugated structure consisting of 7 or more atoms, and other components as needed, and then heating, drying, and exposing the substrate as needed to form a scintillator layer.

[0121] Examples of coating methods for phosphor pastes include screen printing, and methods using rod coaters, roller coaters, die coaters, and doctor blade coaters. Among these, roller coaters and die coaters are preferred for their ability to easily coat even thick films and ensure uniform film thickness of the scintillator layer. In die coaters, the use of a slit die coater allows for adjustment of the scintillator layer thickness by controlling the discharge rate, enabling highly precise adjustment of the scintillator layer thickness.

[0122] In addition to the components previously described as forming the scintillator layer, the phosphor paste may also contain organic solvents. The organic solvents are preferably good solvents relative to the binder resin having a π-conjugated structure consisting of 7 or more atoms, as well as plasticizers, dispersants, surface modifiers, etc., as needed. Examples of such organic solvents include, for example, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, triethylene glycol monobutyl ether acetate, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, polyethylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monobutyl ether acetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether... Ethylene glycol phenyl ether, diethylene glycol phenyl ether, hexanediol, isopropanol, methyl ethyl ketone, cyclohexanone, propanol, butanol, terpineol, benzyl alcohol, tetrahydrofuran, dihydroterpineol, γ-butyrolactone, dihydroterpineyl acetate, 3-methoxy-1-butanol, 3-methoxy-3-methyl-1-butanol, 3-methoxy-3-methyl-1-butyl acetate, N,N-dimethylformamide, N-methyl-2-pyrrolidone, etc. It may contain two or more of these.

[0123] The scintillator layer is preferably formed by heating and drying a coating film of phosphor paste. Examples of drying methods include hot air drying and IR (infrared) drying. During the drying of the phosphor paste coating film, the phosphor paste is heated, and its viscosity decreases. Therefore, the sedimentation of the phosphor, which is a relatively high-density material in the phosphor paste, is promoted, increasing the phosphor packing density in the scintillator layer. The heating and drying method for the phosphor paste coating film preferably includes a first step to reduce the amount of residual organic solvent in the phosphor paste coating film to less than 40%, and a second step to reduce the amount of residual organic solvent in the phosphor paste coating film to less than 5%. The heating temperature in the first step is preferably 35–80°C, and the heating time is preferably 10–30 minutes. The heating temperature in the second step is preferably 35–120°C, and the heating time is preferably 120–800 minutes.

[0124] (Radiation detector)

[0125] The radiation detector of the present invention has the aforementioned scintillator panel on an output substrate having a photoelectric conversion layer. The output substrate has a photoelectric conversion layer and an output layer on the substrate. The photoelectric conversion layer is generally a material in which pixels with light sensors are formed.

[0126] (Line scan camera)

[0127] The linear scan camera of the present invention has the aforementioned scintillator panel on a one-dimensional linear output substrate having a photoelectric conversion layer. The output substrate has a photoelectric conversion layer and an output layer on the substrate. The photoelectric conversion layer is generally a material in which pixels with light sensors are formed.

[0128] (Radiation examination device)

[0129] The radiation inspection apparatus of the present invention includes a radiation generating section that generates radiation and the aforementioned radiation detector. The radiation inspection apparatus is a device that irradiates a subject with radiation from the radiation generating section and detects the radiation that has passed through the subject by passing it through the radiation detector. By equipping the radiation detection section with the radiation detector of the present invention, a high-brightness radiation inspection apparatus can be obtained. The radiation inspection apparatus of the present invention can use the aforementioned line scan camera instead of the aforementioned radiation detector.

[0130] The radiation detection device of the present invention is preferably used in industrial applications. In industrial applications, because the radiation detector is continuously irradiated with high-energy radiation for a long time, the radiation dose received by the radiation detection device becomes very large compared to medical applications. The radiation irradiation dose to the scintillator panel inside the radiation detection device also becomes very large, resulting in significant brightness degradation. By incorporating the radiation detector of the present invention in these applications, a high-brightness radiation inspection device with suppressed brightness degradation can be obtained. Here, "industrial application" in the present invention refers to applications where radiation is not directly irradiated onto the human body, and "medical application" refers to applications where radiation is directly irradiated onto the human body, i.e., applications for medical purposes.

[0131] (Online inspection method)

[0132] The online inspection method of the present invention uses the aforementioned radiation inspection apparatus. The online inspection method is a non-destructive and continuous inspection of a subject in the manufacturing process of electronic components, food, etc., where the radiation inspection apparatus continuously irradiates a mounted radiation detector with radiation for an extended period. By using the radiation inspector of the present invention with this radiation inspection apparatus, an online inspection method is achieved that can suppress brightness degradation even under continuous radiation irradiation.

[0133] (Offline check)

[0134] The offline inspection method of the present invention uses the aforementioned radiation inspection apparatus. The offline inspection method is a non-destructive and discontinuous method for inspecting objects such as aircraft components and infrastructure. In the offline inspection method, it is preferable that the tube voltage in the radiation irradiation section of the radiation inspection apparatus is high, for example, preferably 70 kV or higher, during the inspection of the internal structure of the object. With a tube voltage of 70 kV or higher, the radiation dose transmitted through the object is high, ensuring that the radiation dose detectable by the radiation detector is sufficient, thus obtaining a high-brightness radiation image. By using the radiation inspector of the present invention with this radiation inspection apparatus, an offline inspection method is achieved that can suppress brightness degradation even under high-tube-voltage radiation irradiation conditions.

[0135] Example

[0136] The present invention will be further illustrated below with examples and comparative examples, but the invention is not limited thereto, nor is it to be interpreted as limited to these examples.

[0137] The materials used in the various embodiments and comparative examples are shown below. Furthermore, the properties of each material were determined by the following methods.

[0138] (Average particle size of phosphors)

[0139] A fluorophore was placed in a water-filled sample chamber of a particle size distribution measuring device (MT3300; manufactured by Nikkiso Co., Ltd.), and the particle size distribution was measured after 300 seconds of ultrasonic treatment. The particle size that accounts for 50% of the cumulative distribution was set as the average particle size.

[0140] (Glass transition temperature of adhesive resin)

[0141] Weigh approximately 10 mg of adhesive resin. Using an aluminum pan and pan cover, heat the sample from 20 °C to 10 °C / min in a nitrogen atmosphere using a differential thermal analysis apparatus (differential type differential thermal balance TG8120; manufactured by Ligaku Co., Ltd.). Measure the temperature spectrum at this point and calculate the glass transition temperature.

[0142] (Weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the adhesive resin)

[0143] A resin solution was prepared by dissolving 2.5 mg of adhesive resin in 5 mL of tetrahydrofuran. Mw and Mn were determined using gel permeation chromatography (GPC-22) and a differential refractive index detector (RI, manufactured by Higashi Soy Co., Ltd., RI-8020 type), with monodisperse polystyrene (manufactured by Higashi Soy Co., Ltd.) as a standard. The GPC column used a mixture of two TSKgel GMHxl (manufactured by Higashi Soy Co., Ltd.) columns connected to one G2500Hxl (manufactured by Higashi Soy Co., Ltd.), with tetrahydrofuran solvent passed through at a flow rate of 1.0 mL / min.

[0144] (Transmittance of the adhesive resin solution)

[0145] A resin solution was prepared by dissolving 0.25 mg of the adhesive resin in 9.75 mg of the solvent listed in Table 1. The transmittance from 300 to 800 nm was measured using a UV-Vis spectrophotometer (Hitachi Hightech Co., Ltd., U-4000) with the solution added to a quartz cell with a 1 cm optical path length. The baseline of each resin solution was corrected for the transmittance of each solvent individually.

[0146] (Eg of adhesive resins)

[0147] The adhesive resin and solvent combinations shown in Table 1 were added to a stirring vessel at a ratio of 5% by weight, and the mixture was heated and stirred at 60°C for 8 hours using an oil bath to prepare an adhesive resin solution. This adhesive resin solution was then coated onto an 8-inch silicon wafer using a spin coater (MS-B150: Mikasa Co., Ltd.), and baked at 100°C for 5 minutes using a hot plate to produce a dried film with a thickness of 700 nm. The extinction coefficient of the dried film relative to 300–800 nm was measured using a spectroscopic ellipsometry (FE-5000: Otsuka Electronics Co., Ltd.), and Eg was calculated from the Tauc plot.

[0148] (Raw materials for fluorescent paste)

[0149] Phosphor powder 1: Gd2O2S:Tb (manufactured by Nichia Chemical Industry Co., Ltd.: average particle size 11μm)

[0150] Phosphor powder 2: Gd2O2S:Pr (manufactured by Nichia Chemical Industry Co., Ltd.: average particle size 5μm).

[0151] Adhesive resin 1: "Bairon" (registered trademark) 103 (the number of constituent atoms of the π-conjugated system structure: 10, equivalent to general formula (1), X 1 : Derived from the organic group of ethylene glycol / neopentyl glycol, Y 1Carbonyl group, Ar: phenylene, glass transition temperature: 47℃, weight average molecular weight: 23,000, polyester resin, Eg = 3.9, amorphous (manufactured by Toyobo Co., Ltd.)

[0152] Adhesive resin 2: "Bairon" (registered trademark) 270 (the number of constituent atoms of the π-conjugated system structure: 10, equivalent to general formula (1), X 1 : Derived from the organic group of ethylene glycol / neopentyl glycol, Y 1 Carbonyl group, Ar: phenylene, glass transition temperature: 67℃, weight average molecular weight: 23,000, polyester resin, Eg = 3.9, amorphous (manufactured by Toyobo Co., Ltd.)

[0153] Adhesive resin 3: "U-polymer" (registered trademark) D type (π-conjugated system structure, number of constituent atoms: 10, equivalent to general formula (1), X 1 : Derived from the organic group of bisphenol A, Y 1 Carbonyl group, Ar: phenylene, glass transition temperature: 193℃, weight average molecular weight: 60,000, polyarylate resin, Eg = 3.5, amorphous (manufactured by Unichika Co., Ltd.)

[0154] Adhesive resin 4: “Grillamid” (registered trademark) TR55 (the number of constituent atoms of the π-conjugated system structure: 10, equivalent to general formula (1), X 1 : An organic group derived from 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, Y 1 Carbonyl group, Ar: phenylene, glass transition temperature: 160℃, weight average molecular weight: 18,000, polyamide resin, Eg = 4.1, amorphous (Made by Emuskemi-Japan Co., Ltd.)

[0155] Adhesive resin 5: "Vieromax" (registered trademark) HR-15ET (the number of constituent atoms of the π-conjugated system structure: 10, equivalent to general formula (2), X 2 : Derived from an organic group of diphenyl ether, t=1, Y 2 Amide group, Ar: group derived from phenyl, glass transition temperature: 260℃, weight average molecular weight: 0.8 million, polyamide-imide resin, Eg = 3.5, amorphous (manufactured by Toyobo Co., Ltd.)

[0156] Adhesive resin 6: "Eslack" (registered trademark) BL-1 (number of constituent atoms of π-conjugated structure: 0, not equivalent to general formulas (1) and (2), glass transition temperature: 70°C, weight-average molecular weight: 19,000, butyral resin, Eg = 3.6, amorphous) (manufactured by Sekisui Chemicals Co., Ltd.)

[0157] Adhesive resin 7: "Bairon" (registered trademark) 630 (the number of constituent atoms of the π-conjugated system structure: 10, equivalent to general formula (1), X 1 : Derived from the organic group of ethylene glycol / neopentyl glycol, Y 1 Carbonyl group, Ar: phenylene, glass transition temperature: 7℃, weight average molecular weight: 23,000, polyester resin, Eg = 3.9, amorphous (manufactured by Toyobo Co., Ltd.)

[0158] Adhesive resin 8: "Eupiron" (registered trademark) H-4000 (number of constituent atoms of π-conjugated structure: 6, not equivalent to general formulas (1) and (2), glass transition temperature: 146℃, weight-average molecular weight: 30,000, polycarbonate resin, Eg = 4.4, amorphous) (Made by Mitsubishi Engineering Plus Corporation)

[0159] Adhesive resin 9: "Parapet" (registered trademark) GH-S (number of constituent atoms of π-conjugated structure: 0, not equivalent to general formulas (1) and (2), glass transition temperature: 104℃, weight-average molecular weight: 81,000, acrylic resin, Eg = 4.7, amorphous) (Kurare Co., Ltd.)

[0160] Adhesive resin 10: Styrene polymer (π-conjugated structure: 6 atoms, not equivalent to general formula (1), (2), glass transition temperature: 100℃, weight average molecular weight: 200,000, polystyrene, Eg = 4.4, amorphous) (manufactured by Fuji Film Wako Pure Medicine Co., Ltd.).

[0161] (Preparation of adhesive resin solution)

[0162] Each adhesive resin and solvent was added to a mixing container in the proportions shown in Table 1, and the mixture was heated and stirred at 60°C for 8 hours using an oil bath to obtain adhesive resin solutions 1 to 10.

[0163] (Raw materials for pastes containing glass powder)

[0164] Photosensitive monomer M-1: Trimethylolpropane triacrylate

[0165] Photosensitive monomer M-2: Tetrapropylene glycol dimethacrylate

[0166] Photosensitive polymer 1: A substance obtained by adding 0.4 equivalents of glycidyl methacrylate to the carboxyl groups of a copolymer formed from methacrylic acid / methyl methacrylate / styrene in a mass ratio of 40 / 40 / 30 (weight average molecular weight 43,000; acid value 100).

[0167] Photopolymerization initiator 1: 2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1 (manufactured by BASF)

[0168] Polymerization inhibitor 1: 1,6-hexanediol-bis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]

[0169] UV absorber solution 1: 0.3% by mass solution of γ-butyrolactone from Stan IV (manufactured by Tokyo Ohka Kogyo Co., Ltd.)

[0170] Viscosity modifier 1: "Floron" (registered trademark) EC121 (manufactured by Kyoeisha Chemical Co., Ltd.)

[0171] Solvent 1: γ-Butyrolactone

[0172] Low softening point glass powder 1: SiO2 27% by mass, B2O3 31% by mass, ZnO 6% by mass, Li2O 7% by mass, MgO 2% by mass, CaO 2% by mass, BaO 2% by mass, Al2O3 23% by mass, refractive index (ng) 1.56, glass softening temperature 588℃, coefficient of thermal expansion 70×10⁻⁶ -7 (K -1 The average particle size is 2.3 μm.

[0173] (Preparation of paste containing glass powder)

[0174] Four parts by mass of photosensitive monomer M-1, six parts by mass of photosensitive monomer M-2, 24 parts by mass of photosensitive polymer 1, six parts by mass of photopolymerization initiator 1, 0.2 parts by mass of polymerization inhibitor 1, and 12.8 parts by mass of ultraviolet absorber solution 1 were added to 38 parts by mass of solvent 2 and heated to dissolve at 80°C. After cooling the resulting solution, nine parts by mass of viscosity modifier 1 were added to obtain organic solution 1. Fifty parts by mass of the aforementioned low softening point glass powder were added to 50 parts by mass of organic solution 1, and the mixture was kneaded using a three-roll mill to obtain paste 1 containing glass powder.

[0175] (Evaluation of the decay time of luminous intensity)

[0176] The scintillator panels fabricated in each embodiment and comparative example were exposed to X-rays with a tube voltage of 70 kVp. The time-varying amount of light emission was measured using a device consisting of an optical fiber (PLG-1-3000-8R, manufactured by Nippon Paint Co., Ltd.), a photodiode (S2281-01, manufactured by Hamamatsu Hotniks Co., Ltd.), and a photodetector amplifier (C9329, manufactured by Hamamatsu Hotniks Co., Ltd.). Then, the time required until the light emission intensity reached 1 / e relative to the moment when X-ray irradiation ceased was calculated.

[0177] (brightness L) ＊ chromaticity a ＊ b ＊ (Evaluation)

[0178] For the scintillator panels fabricated in each embodiment and comparative example, a spectrophotometer CM-2600D (manufactured by Conicaminodesk Ltd.) was installed on the surface of the scintillator layer, and the lightness L at 400–700 nm was measured by SCI method. ＊ chromaticity a ＊ b ＊ .

[0179] (Evaluation of brightness)

[0180] The scintillator panels fabricated in each embodiment and comparative example were placed in a commercially available FPD (Paxscan2520V (manufactured by Varian)) to create an X-ray detector. Radiation with a tube voltage of 70 kVp was applied to the substrate side of the scintillator panel, and the brightness of the scintillator panel was detected using the FPD. The brightness was calculated from the digital value of the image relative to a set incident dose. For Examples 1-7 and Comparative Examples 1-7, the brightness of Comparative Example 1 was set to 100%; for Examples 8-11 and Comparative Examples 8-9, the brightness of Comparative Example 8 was set to 100%; for Examples 12-16 and Comparative Examples 10-14, the brightness of Comparative Example 10 was set to 100%; and for Examples 17-19 and Comparative Examples 15-16, the brightness of Comparative Example 15 was set to 100%. Relative comparisons were performed accordingly.

[0181] (Evaluation of brightness degradation caused by continuous radiation exposure)

[0182] The scintillator panels fabricated in the various embodiments and comparative examples were continuously irradiated with radiation for 14 days at a dose rate of 3 kGy / h. An X-ray detector was fabricated from the irradiated scintillator panels using the method described above, and the brightness of the scintillator panels was detected using an FPD. The brightness was calculated from digital values ​​of an image relative to a set incident dose. The brightness before continuous irradiation in the various embodiments and comparative examples was set to 100%, and the relative value of the brightness after irradiation was calculated.

[0183] (The tightness of the fit between the scintillator layer and the support)

[0184] In each embodiment and comparative example, adhesive tape with an adhesion strength of 5 N / 25 mm was applied to the scintillator layer of the scintillator panel. The tape was peeled off while maintaining a peel angle of 90°, and the presence or absence of defects, cracks, and peeling from the support in the scintillator layer was observed. This test was repeated 50 times, and the maximum number of tests in which no defects / cracks or peeling were observed in the scintillator layer was defined as the adhesion strength. A case where no defects / cracks or peeling were observed in the scintillator layer even after 20 peels was evaluated as A; a case where peeling of the scintillator layer was not observed up to 20 peels was evaluated as B; and a case where peeling of the scintillator layer was observed up to 5 peels was evaluated as C.

[0185] (Evaluation of the deterioration of seal strength caused by continuous radiation exposure)

[0186] The scintillator panels fabricated in the various embodiments and comparative examples were continuously irradiated for 14 days at a dose rate of 3 kGy / h. The adhesion strength between the scintillator layer and the support was evaluated using the method described above.

[0187] (Example 1)

[0188] The raw materials were added to a mixing container at the ratios listed in Table 2 and mixed. A planetary stirring and degassing apparatus (“Mazer Star” (registered trademark) KK-400; manufactured by Kurashiki Spinning Co., Ltd.) was used to stir and degas at 1000 rpm for 20 minutes to obtain phosphor paste A-1. The obtained phosphor paste 1 was coated onto substrate E20 (white PET film; manufactured by Higashi Re Co., Ltd.) with a dried film thickness of 200 μm using a die coater. The coating was then heated and dried at 70°C for 180 minutes to obtain a scintillator panel with a scintillator layer formed on the substrate.

[0189] (Examples 2-11, Comparative Examples 1-9)

[0190] Instead of phosphor paste A-1, the phosphor pastes listed in Tables 2 to 4 were used, and the scintillator panel was obtained by operating in the same manner as in Example 1.

[0191] (Example 12)

[0192] (Fabrication of spacers on the substrate)

[0193] A 125mm × 125mm × 0.7mm sodium glass plate was used as the substrate. A paste 1 containing glass powder was applied to the surface of the substrate using a die-coating machine to a dried thickness of 220μm, and then dried to obtain a coating film containing glass powder 1. Next, an ultra-high pressure mercury lamp at 300mJ / cm² was used. 2The coating film containing glass powder was exposed to the desired pattern using a photomask (a chromium mask with a 127 μm pitch and 15 μm linewidth, featuring a lattice-shaped opening) through an aperture corresponding to the desired pattern. The exposed coating film was developed in a 0.5% by mass aqueous ethanolamine solution to remove unexposed portions, resulting in a lattice-shaped pattern. The resulting lattice-shaped pattern was then fired in air at 580°C for 15 minutes to form a lattice-shaped spacer wall with glass as the main component.

[0194] (Form of the reflective layer)

[0195] A commercially available sputtering apparatus and sputtering target were used to form a metal film as a reflective layer on a substrate with the aforementioned spacers. Regarding the thickness of the metal film, sputtering was performed with a glass plate placed near the substrate where the spacers were formed, and the metal film thickness on this glass plate was 300 nm. The sputtering target was APC (Fullya Metals Co., Ltd.), a silver alloy containing palladium and copper. After forming the metal reflective layer, SiN as a protective layer was formed on the glass substrate with a thickness of 100 nm during the same vacuum interval.

[0196] (Formation of an organic protective layer)

[0197] A resin solution was prepared by mixing 1 part by mass of the fluorinated solvent CT-SOLV180 (AGC Co., Ltd.) with 1 part by mass of the amorphous fluorinated resin "CYTOP" (registered trademark) CTL-809M (manufactured by AGC Co., Ltd.) as a solvent.

[0198] After vacuum printing the resin solution onto a spacer substrate with a metal reflective layer and an inorganic protective layer, it was dried at 90°C for 1 hour and then cured at 190°C for 1 hour to form an organic protective layer. The thickness of the organic protective layer on the central side of the spacer in the height direction of the spacer substrate was measured to be 1 μm by exposing the cross-section of the spacer using a three-ion beam cutting device EMTIC3X (manufactured by LEICA) and photographed using a field emission scanning electron microscope (FE-SEM) Merlin (manufactured by Cartzis Co., Ltd.).

[0199] Phosphor paste A-11 was prepared in the same manner as in Example 1. The obtained phosphor paste A-11 was filled into a spacer substrate with a reflective layer by vacuum printing and dried at 150°C for 30 minutes to obtain a scintillator panel in which a scintillator layer is formed inside the spacer.

[0200] (Examples 13-19, Comparative Examples 10-16)

[0201] Instead of phosphor paste A-11, the phosphor pastes described in Tables 5-6 were used, and otherwise, the scintillator panel was obtained by operating in the same manner as in Example 12.

[0202] The configuration and results of each embodiment and comparative example are shown in Tables 2 to 6.

[0203] [Table 1]

[0204]

[0205] [Table 2]

[0206]

[0207] [Table 3]

[0208]

[0209] [Table 4]

[0210]

[0211] [Table 5]

[0212]

[0213] [Table 6]

[0214]

[0215] Explanation of symbols

[0216] 1X-ray detector

[0217] 2 Scintillator Panel

[0218] 3 Output Board

[0219] 4 Scintillator layer

[0220] 5 substrates

[0221] 6 fluorescent cells

[0222] 7 Adhesive Resin

[0223] 8 membrane layers

[0224] 9 photoelectric conversion layer

[0225] 10 Output Layer

[0226] 11 base plate

[0227] 12 Power Supply Section

[0228] 13. Spacer wall.

Claims

1. A linear array camera having a scintillator panel on an output substrate having a photoelectric conversion layer, the scintillator panel having a substrate and a scintillator layer containing a phosphor, the scintillator layer comprising an adhesive resin having a π-conjugated structure consisting of 7 or more atoms, the adhesive resin having a structure in its main chain as shown in general formula (1) or general formula (2), and the glass transition temperature of the adhesive resin being 30 to 430°C, and the film thickness of the scintillator layer being 50 to 800 μm. In the general formula (1) and general formula (2), X 1 , X 2 , Y 1 , and Y 2 each independently represent a divalent organic group; Ar represents an aromatic hydrocarbon group; and t represents an integer of 1 or 2.

2. The linear array camera according to claim 1, wherein the adhesive resin has a π-conjugated structure consisting of 30 or fewer atoms.

3. The linear array camera according to claim 1 or 2, wherein the solution containing 2.5% by weight of the adhesive resin has a transmittance of 85% or more at an optical path length of 1 cm and a wavelength of 400 nm.

4. In the linear array camera according to claim 1 or 2, the energy level difference Eg between the highest occupied molecular orbital and the lowest unoccupied molecular orbital of the adhesive resin is greater than 2.0 eV and less than 4.2 eV.

5. The line array camera according to claim 1 or 2, wherein the weight-average molecular weight of the adhesive resin is in the range of 5,000 to 100,000.

6. The linear array camera according to claim 1 or 2, wherein the volume ratio of the phosphor to the adhesive resin in the scintillator layer is phosphor: adhesive resin = 80:20 to 95:

5.

7. The linear array camera according to claim 1 or 2, wherein the phosphor contains gadolinium oxysulfide.

8. The linear array camera according to claim 1 or 2, wherein the time for the phosphor to reach 1 / e times the initial luminescence intensity is less than 100 μs.

9. The linear array camera according to claim 1 or 2, having spacers dividing the scintillator layer.

10. A radiation inspection apparatus comprising the linear array camera of claim 1.

11. The radiation examination apparatus according to claim 10, which is used for industrial purposes.

12. An online examination method using the radiation examination apparatus of claim 10 or 11.

13. An inspection method, which is an offline inspection method using the radiation inspection device of claim 10 or 11, wherein the tube voltage during radiation irradiation is 70kV or higher.

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