JP2009068888A - Flat panel detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat panel detector (FPD) protecting a phosphor layer from chemical deterioration or physical impact, preventing characteristic deterioration with elapse of time of the phosphor layer, and keeping a contact state between a scintillator panel and a planar light receiving element to be uniform, excellent, and stable. <P>SOLUTION: This flat panel detector wherein a scintillator plate having a scintillator layer provided on a substrate, and the scintillator panel comprising a protection layer for coating the whole surface on the scintillator layer side of the scintillator plate are arranged on the planar light receiving element surface, has a characteristic wherein the bending elastic modulus of the outermost layer of the protection layer is in the range of 50-2,500 MPa. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flat panel detector used when a radiographic image of a subject is formed. More specifically, the present invention relates to a flat panel detector provided with a scintillator panel in which the contact state between the scintillator panel and a planar light receiving element is good.

  Conventionally, radiographic images such as X-ray images have been widely used for diagnosis of medical conditions in the medical field. In particular, radiographic images using intensifying screen (film) -film systems have been developed as an imaging system that combines high reliability and excellent cost performance as a result of high sensitivity and high image quality in the long history. It is used at medical sites around the world. However, these pieces of image information are so-called analog image information, and free image processing and instantaneous electric transmission cannot be performed like the digital image information that has been developed in recent years.

  In recent years, digital radiological image detection apparatuses represented by computed radiography (CR), flat panel type radiation detectors (FPD), and the like have appeared. In these, since a digital radiographic image is directly obtained and an image can be directly displayed on an image display device such as a cathode tube or a liquid crystal panel, image formation on a photographic film is not necessarily required. As a result, these digital X-ray image detection devices reduce the need for image formation by the silver halide photography method, and greatly improve the convenience of diagnosis work in hospitals and clinics.

  As described above, computed radiography (CR) is currently accepted in the medical field as one of digital techniques for X-ray images. However, sharpness is insufficient and spatial resolution is insufficient, and the image quality level of the intensifying screen (screen) film system has not been reached.

  Further, as new digital X-ray imaging techniques, for example, the magazine Physics Today, November 1997, page 24, John Laurans's paper “Amorphous Semiconductor User in Digital X-ray Imaging”, magazine SPIE Vol. 32, 1997. A flat-plate X-ray detector using a thin film transistor (TFT) developed by El E. Antonuk's paper “Development of a High Resolution, Active Matrix, Flat-Panel Image with Enhanced Fill Factor”, etc. Has been.

  A scintillator plate made of an X-ray phosphor having the property of emitting light by radiation is used to convert the radiation into visible light. In order to improve the S / N ratio in low-dose imaging, the luminous efficiency is improved. It will be necessary to use high scintillator plates.

  In general, the light emission efficiency of the scintillator plate is determined by the thickness of the phosphor layer and the X-ray absorption coefficient of the phosphor. The thicker the phosphor layer, the more scattered the emitted light in the phosphor layer. Occurs and sharpness decreases. Therefore, when the sharpness necessary for the image quality is determined, the film thickness is determined. Among various phosphors, cesium iodide (CsI) has a relatively high rate of change from X-rays to visible light, and can easily form phosphors into a columnar crystal structure by vapor deposition. Scattering of the emitted light was suppressed, and it was possible to increase the thickness of the phosphor layer.

  However, since CsI alone has low luminous efficiency, a mixture of CsI and sodium iodide (NaI) in an arbitrary molar ratio is used as a sodium salt on a substrate by vapor deposition, as disclosed in, for example, Japanese Patent Publication No. 54-3560. Deposited as activated cesium iodide (CsI: Na), or in recent years, a mixture of CsI and thallium iodide (TlI) in an arbitrary molar ratio is deposited on a substrate using sodium activated thallium iodide (CsI: Visible conversion efficiency is improved by annealing the deposited Tl) as a post process, and it is used as an X-ray phosphor.

However, the scintillator (phosphor layer) based on CsI has a deliquescent property and has a drawback that the characteristics deteriorate with time. In order to prevent such deterioration over time, it has been proposed to form a moisture-proof protective layer on the surface of a scintillator (phosphor layer) based on CsI. For example, a method of covering an upper part, a side surface, and an outer peripheral part of the scintillator layer of a scintillator layer (corresponding to the phosphor layer of the present invention) with polyparaxylylene resin is known (see, for example, Patent Document 1). Further, a method is known in which a transparent resin film having a moisture permeability of less than 1.2 g / m ² · day covers at least the side of the scintillator layer opposite to the side facing the support and the side surface (see, for example, Patent Document 2). reference). These protective layers provide high moisture resistance.

  Generally, when the scintillator panel is disposed on the surface of the planar light receiving element, a cushion member is provided between the protective cover and the scintillator panel, and the scintillator panel is compressed by the pressure of the cushion member compressed when the protective cover is attached. The light receiving element is brought into pressure contact with an appropriate pressure. Therefore, when assembling the radiation image detector, the scintillator panel and the cushion member are sequentially placed on the light receiving element arranged in the casing, and then the protective cover is fixed to the casing with screws or the like.

  At this time, if the pressure of the cushion member is too strong, the tip of the phosphor crystal having a columnar crystal structure is crushed and the contrast of the radiation image is lowered. On the contrary, when the pressure of the cushion member is weak, positional deviation occurs between the scintillator panel surface and the planar light receiving element surface when the FPD is directed downward or due to vibration, and the signal correction accuracy at each pixel of the planar light receiving element decreases. However, the graininess and sharpness of the obtained image deteriorate. There is also a problem that defects are likely to occur in the planar light receiving element and the phosphor layer due to friction between the scintillator panel and the planar light receiving element due to movement and vibration of the FPD device.

  In general, a phosphor layer needs to have a thickness of 400 μm or more in order to obtain a radiographic image with high graininess. However, the increase in the mass of the scintillator panel and the increase in the size of the scintillator panel due to the increase in film thickness make this problem more serious. To.

  In order to solve such a problem, a method of fixing the scintillator panel and the planar light receiving element with an adhesive (for example, refer to Patent Document 1), a method of bonding with a matching oil (for example, refer to Patent Document 2), etc. are proposed. However, there are problems such as the occurrence of unevenness in the adhesive and matching oil and an increase in work man-hours. In addition, this method cannot be disassembled and repaired, and the scintillator panel cannot be replaced.

  Conventionally, as a manufacturing method of a scintillator by a vapor phase method, a phosphor layer is generally formed on a rigid substrate such as aluminum or amorphous carbon, and the entire surface of the scintillator is covered with a protective film thereon ( For example, see Patent Document 3). However, when a phosphor layer is formed on these substrates that cannot be bent freely, the flat surface of the scintillator panel and the planar light-receiving element is affected by the processing accuracy of the substrate and deformation during vapor deposition. There is a drawback that a uniform contact state between the scintillator panel surface and the light receiving element surface cannot be achieved on the entire surface of the panel detector, and uniform image quality characteristics cannot be obtained within the surface. This problem has become more serious with the recent increase in the size of flat panel detectors.

  In order to avoid this problem, a method of forming a scintillator directly by vapor deposition on an image sensor or a medical intensifying screen having low sharpness but having flexibility is generally used as a substitute. Yes.

From this situation, the production is excellent, the deterioration of the phosphor layer over time is prevented, the phosphor layer is protected from chemical alteration or physical shock, and the contact state between the scintillator panel and the planar light receiving element. However, it is desired to develop a radiation flat panel detector that is stable.
JP 2006-189377 A JP 2000-9845 A Japanese Patent No. 3669926

  The present invention has been made in view of the above-mentioned problems and situations, and its solution is to protect the phosphor layer from chemical alteration or physical impact and prevent deterioration of the phosphor layer over time. The present invention is to provide a flat panel detector (FPD) in which the contact state between the scintillator panel and the planar light-receiving element is uniform and favorable.

  As a result of intensive studies to solve the above problems, the inventors have made a protective layer that covers the phosphor surface in order to allow the scintillator panel surface and the planar light receiving element surface to be uniformly and satisfactorily adhered to each other. The flexibility of the outermost layer was found to be important, and the present invention was achieved.

  That is, the said subject which concerns on this invention is solved by the following means.

  1. In a flat panel detector in which a scintillator panel comprising a scintillator plate provided with a scintillator layer on a substrate and a protective layer covering the scintillator layer side surface of the scintillator plate is disposed on a planar light receiving element surface, the outermost layer of the protective layer A flat panel detector having a flexural modulus of 50 to 2500 MPa.

  2. 2. The flat panel detector according to 1 above, wherein the protective layer is made of a polymer film.

  3. 3. The flat panel detector according to 2 above, wherein the polymer film has a thickness of 12 to 200 μm.

  4). 4. The flat panel detector as described in 2 or 3 above, wherein the scintillator panel is sealed by vacuum adhesion using the polymer film.

  5). The flat panel detector according to any one of claims 1 to 4, wherein the scintillator layer is formed by a vapor deposition method.

  6). The flat panel detector according to any one of 1 to 5, wherein the scintillator layer contains cesium iodide as a main component.

  7. The flat panel detector according to any one of 1 to 6 above, wherein the substrate contains polyimide, polyethylene naphthalate, or graphite as a main component and has a thickness of 50 to 500 μm.

  8). The flat panel detector according to any one of claims 1 to 6, wherein a total thickness of the scintillator panel is 1 mm or less.

  By the above means of the present invention, the phosphor layer is protected from chemical alteration or physical impact, the characteristic deterioration of the phosphor layer over time is prevented, and the contact state between the scintillator panel and the planar light receiving element is uniform and good. A stable flat panel detector (FPD) can be provided.

  A flat panel detector of the present invention is a flat panel detector in which a scintillator panel comprising a scintillator plate provided with a scintillator layer on a substrate and a protective layer covering the scintillator layer side surface of the scintillator plate is disposed on a planar light receiving element surface. The bending elastic modulus of the outermost layer of the protective layer is 50 to 2500 MPa (standard: measured value by a method based on ASTM D 790 test method). This feature is a technical feature common to the inventions according to claims 1 to 8.

  In a preferred embodiment, the protective layer is preferably made of a polymer film. Moreover, it is preferable that the thickness of the said polymer film is 12-200 micrometers. Furthermore, the aspect by which the said scintillator panel is sealed by pressure reduction adhesion using the said polymer film is preferable.

  In the present invention, the scintillator layer is preferably formed by a vapor deposition method and contains cesium iodide as a main component.

  As a board | substrate which concerns on this invention, the aspect which contains a polyimide, a polyethylene naphthalate, or a graphite as a main component, and the thickness is 50-500 micrometers is preferable. Furthermore, it is preferable that the total thickness of the scintillator panel is 1 mm or less.

  Hereinafter, the present invention, its components, and the best mode and mode for carrying out the invention will be described in detail.

(Configuration of scintillator panel)
The scintillator panel according to the present invention includes a scintillator plate provided with at least a scintillator layer on a substrate, and a protective layer covering the surface (preferably the entire surface) of the scintillator plate on the scintillator layer side. Note that a reflective layer, an insulating layer, or the like may be provided over the substrate in accordance with various purposes.

  Hereinafter, each constituent layer and constituent elements will be described.

(Protective layer)
The protective layer according to the present invention focuses on protecting the scintillator layer. That is, cesium iodide (CsI) absorbs water vapor in the air and deliquesces when exposed to a high hygroscopic property, and therefore the main purpose is to prevent this.

  The protective layer according to the present invention is characterized in that the outermost layer has a flexural modulus of 50 to 2500 MPa. Here, the “outermost layer” refers to the protective layer itself when the protective layer has a single layer configuration (single film). In addition, when the protective layer is composed of a plurality of layers, that is, composed of a plurality of layers, it indicates a layer farthest from the substrate among the plurality of layers. For example, when the protective layer has a three-layer structure: outermost layer / intermediate layer / innermost layer (/ phosphor layer / substrate) as in the example described later, the outermost layer of the three layers located at the farthest position from the substrate. Refers to the outer layer. Therefore, the outermost layer of the protective layer is a layer in which the scintillator panel is in contact with the planar light receiving element surface.

  When the bending elastic modulus of the outermost layer is less than 50 MPa, there is a problem in mechanical strength as a layer. When the bending elastic modulus is higher than 2500 MPa, uniform and good adhesion between the scintillator panel surface and the planar light receiving element surface is obtained. It becomes difficult to obtain.

  In the present application, the flexural modulus is a value measured by a method based on the ASTM D 790 test method.

  In the present invention, the protective layer is preferably made of a polymer film. Moreover, it is preferable that the thickness of the said polymer film is 12-200 micrometers. Furthermore, the aspect by which the said scintillator panel is sealed by pressure reduction adhesion using the said polymer film is preferable.

  As a configuration example of a preferred embodiment of the protective layer according to the present invention, a multilayer laminated configuration having a configuration of outermost layer (protective function layer) / intermediate layer (moisture-proof layer) / innermost layer (thermal welding layer) can be mentioned. Further, each layer can be added as necessary.

  A polymer film (also referred to as “resin film”) covers the entire scintillator plate (front side: scintillator layer surface and back side: substrate surface) to form a scintillator panel. At this time, the front side and back side configurations are different. It does not matter. In particular, the front side is referred to as a first protective layer and the back side is referred to as a second protective layer. It is important that the first protective layer has a high visible light transmittance particularly at the emission wavelength of the scintillator and is a thin film.

  In terms of cost and performance, the intermediate layer (moisture-proof layer) often uses a metal thin film in which the first protective layer is an expensive colorless transparent type and the second protective layer is a non-transparent type.

  The contents, functions, etc. of each layer in the case of a multilayer (three layers) configuration will be described below.

<Outermost layer: protective functional layer>
In the present invention, the outermost layer has a flexural modulus of 50 to 2500 MPa. As the outermost layer of such a flexible protective layer, a known acrylic, silicone or rubber flexible polymer (resin) can be used.

  As the rubber polymer, a block copolymer such as styrene-isoprene-styrene, a synthetic rubber such as polybutadiene or polybutylene, a natural rubber, or the like can be used.

  Moreover, as a silicone type, you may use a peroxide bridge | crosslinking type and an addition condensation type alone or in a mixture. Furthermore, it can be used by mixing with an acrylic or rubber polymer, or a polymer in which a silicone component is pendant on the polymer main chain or side chain of the acrylic polymer may be used.

  Japanese Patent Laid-Open No. 2000-56694 includes a laminate in which a rubber layer is laminated on one side of a transparent film layer having a light transmittance of 80% or more, and the light transmittance of the laminate is 80% or more. The protective film for screens characterized by these is disclosed. The rubber layer is formed from any one rubber or a mixture of two or more rubbers selected from the group consisting of silicone rubber, fluoro rubber, acrylic rubber, ethylene propylene rubber, and acrylonitrile butadiene rubber. These are also suitable for the flat panel detector of the present invention.

  As the protective layer according to the present invention, the effect of the present invention can be obtained as long as the outermost layer has flexibility. However, as this protective layer configuration, a commercially available film is dry laminated even if the outermost layer is a coating layer. You may provide by bonding by the law.

  Furthermore, when the scintillator panel and the planar light receiving element surface are bonded together, the image quality is not uniform within the light receiving surface of the flat panel detector due to the influence of deformation of the substrate and warpage during vapor deposition. By making the substrate a polymer film having a thickness of 50 to 500 μm and making the total thickness of the scintillator panel 1 mm or less, the scintillator panel is deformed into a shape that matches the planar light receiving element surface shape, and the light receiving surface of the flat panel detector It was found that uniform sharpness was obtained as a whole, and the present invention was achieved.

<Intermediate layer (moisture-proof layer)>
As the intermediate layer (moisture-proof layer), a layer having at least one inorganic film as described in JP-A-6-95302 and the vacuum handbook revised edition p132 to 134 (ULVAC Japan Vacuum Technology KK) is used. Can be mentioned. Examples of the inorganic film include a metal vapor-deposited film and an inorganic oxide vapor-deposited film.

Examples of the metal vapor deposition film include ZrN, SiC, TiC, Si ₃ N ₄ , single crystal Si, ZrN, PSG, amorphous Si, W, and aluminum. Particularly preferable metal vapor deposition films include, for example, aluminum. Can be mentioned.

Thin film handbooks p879-901 (Japan Society for the Promotion of Science), vacuum technology handbooks p502-509, p612, p810 (Nikkan Kogyo Shimbun), vacuum handbook revised edition p132-134 (ULVAC Japan Vacuum Technology KK) Inorganic vapor-deposited films as described in (1). As these inorganic vapor deposition films, for example, Cr ₂ O ₃ , Si _x O _y (x = 1, y = 1.5 to 2.0), Ta ₂ O ₃ , ZrN, SiC, TiC, PSG, Si ₃ N ₄ , single crystal Si, amorphous Si, W, AI ₂ O ₃ or the like is used.

  The thermoplastic polymer (resin) film used as the base material of the intermediate layer (moisture-proof layer) includes ethylene tetrafluoroethyl copolymer (ETFE), high-density polyethylene (HDPE), expanded polypropylene (OPP), polystyrene ( PS), polymethyl methacrylate (PMMA), biaxially oriented nylon 6, polyethylene terephthalate (PET), polycarbonate (PC), polyimide, polyether styrene (PES), etc. can do.

  As a method for forming a deposited film, vacuum technology handbook and packaging technology Vol 29-No. 8, for example, a resistance or high-frequency induction heating method, an electrobeam (EB) method, plasma (PCVD), or the like. The thickness of the deposited film is preferably in the range of 40 to 200 nm, more preferably in the range of 50 to 180 nm.

<Innermost layer (thermal welding layer)>
Examples of the innermost thermoplastic polymer (resin) film include EVA, PP (polypropylene), LDPE (low density polyethylene), LLDPE (linear low density polyethylene) and LDPE, LLDPE produced using a metallocene catalyst, It is preferable to use a film in which these films and HDPE (high density polyethylene) film are mixed and used.

  In addition, as a method for producing these polymer films, various generally known methods are used. For example, a wet laminating method, a dry laminating method, a hot melt laminating method, an extrusion laminating method, or a thermal laminating method is used. It is possible to make it. Of course, the same method can be used when a film on which an inorganic material is deposited is not used, but in addition to these, depending on the material used, it can be formed by a multilayer inflation method or a coextrusion method.

  As the adhesive used for laminating, generally known adhesives can be used. For example, polyolefin thermoplastic resins such as various polyethylene resins and various polypropylene resins, hot-melt adhesives, ethylene-propylene copolymer resins, ethylene-vinyl acetate copolymer resins, ethylene-ethyl acrylate copolymer resins, and other ethylene copolymers. There are thermoplastic resin hot-melt adhesives such as polymer resins, ethylene-acrylic acid copolymer resins and ionomer resins, and other hot-melt rubber adhesives.

  Typical examples of emulsion-type adhesives that are emulsion and latex adhesives are polyvinyl acetate resin, vinyl acetate-ethylene copolymer resin, vinyl acetate and acrylate copolymer resin, vinyl acetate and maleate ester. There are emulsions such as copolymer resins, acrylic acid copolymers, and ethylene-acrylic acid copolymers.

  Typical examples of latex adhesives include rubber latexes such as natural rubber, styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), and chloroprene rubber (CR). In addition, as adhesives for dry lamination, there are isocyanate adhesives, urethane adhesives, polyester adhesives, etc. In addition, paraffin wax, microcrystalline wax, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer. Known adhesives such as hot melt laminate adhesives, pressure sensitive adhesives, heat sensitive adhesives and the like blended with polymer resins can also be used.

  More specifically, the polyolefin-based resin adhesive for extrusion laminating includes, in addition to polymers and ethylene copolymer (EVA, EEA, etc.) resins made of polyolefin resins such as various polyethylene resins, polypropylene resins and polybutylene resins, Ionomer resin (ionic copolymer resin) such as L-LDPE resin copolymerized with ethylene and other monomers (α-olefin), DuPont Surlyn, Mitsui Polychemical Co., Ltd., and Mitsui Petrochemical Admer (adhesive polymer), etc.

  Other UV curable adhesives have recently begun to be used. In particular, LDPE resin and L-LDPE resin are preferable because they are inexpensive and have excellent laminating properties. A mixed resin in which two or more of the above resins are blended to cover the defects of each resin is particularly preferable. For example, when L-LDPE resin and LDPE resin are blended, spreadability is improved and neck-in is reduced, so that the lamination speed is improved and pinholes are reduced.

  The thickness of the polymer (resin) film is preferably 12 to 200 μm in consideration of the formation of voids, the protection of the scintillator (phosphor) layer, sharpness, moisture resistance, workability, etc. Furthermore, 20-60 micrometers is preferable.

  The haze ratio is preferably 3% or more and 40% or less, more preferably 3% or more and 10% or less in consideration of sharpness, radiation image unevenness, manufacturing stability, workability, and the like. A haze rate shows the value measured by Nippon Denshoku Industries Co., Ltd. NDH 5000W. The required haze ratio is appropriately selected from commercially available resin (polymer) films and can be easily obtained.

  The light transmittance of the polymer film is preferably 70% or more at 550 nm in consideration of photoelectric conversion efficiency, scintillator emission wavelength, etc., but a film having a light transmittance of 99% or more is difficult to obtain industrially. Therefore, it is preferably substantially 99% to 70%.

The moisture permeability of the polymer film is preferably 50 g / m ² · day (40 ° C., 90% RH) (measured in accordance with JIS Z0208) or less, more preferably 10 g / m ² taking into account the protection and deliquescence properties of the scintillator layer. m ² · day (40 ° C, 90% RH) (measured according to JIS Z0208) or less is preferable, but a film with a water vapor transmission rate of 0.01 g / m ² · day (40 ° C, 90% RH) or less is industrial. Is practically 0.01 g / m ² · day (40 ° C, 90% RH) or more, 50 g / m ² · day (40 ° C., 90% RH) (measured according to JIS Z0208) ) Or less, more preferably 0.1 g / m ² · day (40 ° C./90% RH) or more and 10 g / m ² · day (40 ° C./90% RH) (measured according to JIS Z0208) or less. .

<Insulation layer>
Any known insulating layer can be used as long as it electrically insulates the metallic reflective layer and the scintillator layer, but it is formed by applying and drying a polymer (resin) dissolved in a solvent. Is preferred. It is preferable that the glass transition point is a polymer having a temperature of 30 to 100 ° C. in terms of attaching a film between the deposited crystal and the substrate. Specifically, a polyurethane resin, a vinyl chloride copolymer, a vinyl chloride-vinyl acetate copolymer, Vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer, polyamide resin, polyvinyl butyral, polyester resin, cellulose derivative (nitrocellulose, etc.), styrene-butadiene copolymer, various Synthetic rubber resins, phenol resins, epoxy resins, urea resins, melamine resins, phenoxy resins, silicon resins, acrylic resins, urea formamide resins and the like can be mentioned, and polyester resins are particularly preferable.

  The thickness of the insulating layer is preferably 0.1 μm or more from the viewpoint of adhesion, and preferably 3.0 μm or less from the viewpoint of ensuring the smoothness of the surface of the insulating layer. More preferably, the thickness of the insulating layer is in the range of 0.2 to 2.5 μm.

  Solvents used for preparing the insulating layer include lower alcohols such as methanol, ethanol, n-propanol and n-butanol, hydrocarbons containing chlorine atoms such as methylene chloride and ethylene chloride, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, toluene , Aromatic compounds such as benzene, cyclohexane, cyclohexanone, xylene, esters of lower fatty acids and lower alcohols such as methyl acetate, ethyl acetate, butyl acetate, ethers such as dioxane, ethylene glycol monoethyl ester, ethylene glycol monomethyl ester and the like Can be mentioned.

(Scintillator layer)
As a material for forming the scintillator layer (also referred to as “phosphor layer”), various known phosphor materials can be used. However, the rate of change from X-ray to visible light is relatively high, and it is easy to perform by vapor deposition. In addition, since the phosphor can be formed into a columnar crystal structure, scattering of the emitted light within the crystal can be suppressed by the light guide effect, and the thickness of the scintillator layer (phosphor layer) can be increased. Cesium iodide (CsI) is preferred.

  However, since only CsI has low luminous efficiency, various activators are added. For example, as shown in Japanese Patent Publication No. 54-35060, a mixture of CsI and sodium iodide (NaI) at an arbitrary molar ratio can be mentioned. Also, for example, CsI as disclosed in Japanese Patent Application Laid-Open No. 2001-59899 is deposited, and indium (In), thallium (Tl), lithium (Li), potassium (K), rubidium (Rb), sodium (Na CsI containing an activating substance such as) is preferred.

  In the present invention, it is particularly preferable to use an additive containing one or more types of thallium compounds and cesium iodide as raw materials. That is, thallium-activated cesium iodide (CsI: Tl) is preferable because it has a broad emission wavelength from 400 nm to 750 nm.

  As the thallium compound as an additive containing one or more types of thallium compounds according to the present invention, various thallium compounds (compounds having oxidation numbers of + I and + III) can be used.

  In the present invention, preferred thallium compounds are thallium iodide (TlI), thallium bromide (TlBr), thallium chloride (TlCl) and the like.

  The melting point of the thallium compound according to the present invention is preferably in the range of 400 to 700 ° C. If the temperature exceeds 700 ° C., the additives in the columnar crystals exist non-uniformly, resulting in a decrease in luminous efficiency. In the present invention, the melting point is a melting point at normal temperature and pressure.

  In the scintillator layer of the present invention, the content of the additive is desirably an optimum amount according to the target performance and the like, but is 0.001 mol% to 50 mol% with respect to the content of cesium iodide, and further 0 It is preferable that it is 1-10.0 mol%.

  Here, when the additive is less than 0.001 mol% with respect to cesium iodide, the target light emission luminance cannot be obtained without much difference from the light emission luminance obtained by using cesium iodide alone. Moreover, when it exceeds 50 mol%, the property and function of cesium iodide cannot be maintained.

(Reflective layer)
The reflective layer according to the present invention exists between the substrate and the scintillator layer. The reflective layer may be a single layer, but in order to improve the adhesion between the graphite sheet and the reflective layer metal, a second metal thin film having a high reflectivity may be provided after the first metal thin film is provided on the substrate. . As the first metal thin film, nickel and an alloy containing nickel are more preferable in view of the stability of the metal itself and the familiarity with other second metal thin films.

  Hereinafter, components of the reflective layer will be described.

<First metal thin film>
Examples of the first metal thin film include nickel, cobalt, and titanium. Nickel and nickel-chromium alloys are more preferable in view of the stability of the metal itself and the familiarity with other second metal thin films. The first metal thin film can be directly deposited on the graphite sheet by vacuum deposition, sputter deposition, or plating, but sputter deposition is preferred from the viewpoint of productivity.

  Regarding the film thickness, although it depends on the adhesion method, it is preferably 10 nm to 100 nm in the case of vacuum deposition and 5 nm to 50 nm in the case of sputter deposition.

<Second metal thin film>
Examples of the second metal thin film include at least one substance selected from the group consisting of aluminum, silver, chromium, nickel, platinum, and gold, and alloys thereof. From the viewpoint of improving the light output of the scintillator plate. Therefore, aluminum or silver having high reflectivity is preferable. The second metal thin film can be directly deposited on the graphite sheet by vacuum deposition, sputter deposition, or plating, but sputter deposition is preferred from the viewpoint of productivity. The film thickness depends on the adhesion method, but is preferably 50 nm to 400 nm for vacuum deposition and 20 nm to 200 nm for sputter deposition.

(substrate)
As the substrate according to the present invention, various metals, carbon, α-carbon, heat-resistant polymer (resin) substrate and the like can be used. However, in view of image characteristics and cost, the heat-resistant polymer (resin) substrate and graphite are used. A substrate is particularly suitable.

  As the heat-resistant polymer (resin), a conventionally known polymer (resin) can be used, but it is preferable to use a so-called engineering plastic. Here, “engineering plastics” are high-performance plastics used in industrial applications (industrial applications), and generally have high strength, heat-resistant temperature, excellent chemical resistance, etc. Have advantages.

  The engineering plastics according to the present invention is not particularly limited. For example, polysulfone resin, polyethersulfone resin, polyimide resin, polyetherimide resin, polyamide resin, polyacetal resin, polycarbonate resin, polyethylene terephthalate resin Polybutylene terephthalate resin, aromatic polyester resin, modified polyphenylene oxide resin, polyphenylene sulfide resin, polyether ketone resin and the like are preferably used. These engineering plastics may be used independently and 2 or more types may be used together.

  Furthermore, depending on the curing temperature, it is also preferable to use a super engineering plastic represented by polyether ether ketone (PEEK), polytetrafluoroethylene (PTFE), or the like.

  In the present invention, as the heat-resistant polymer (resin) substrate, a resin or polyethylene containing polyimide such as polyimide resin or polyetherimide resin, which is excellent in heat resistance, workability, mechanical strength, and cost. It is preferable to form the substrate with naphthalate.

  As the graphite substrate, a substrate containing graphite as a main component is preferably used.

  The graphite substrate is selected from raw material polymer films such as polyphenylene oxadiazole, polybenzothiazole, polybenzobisthiazole, polybenzoxazole, polybenzobisoxazole, polythiazole, aromatic polyamide, and aromatic polyimide. By wrapping around cylindrical graphitic carbon, heating at a temperature of 1800 degrees Celsius or higher in an inert gas or in vacuum, carbonizing (graphitization), and rolling with a roller after carbonization (graphitization), the carbon atoms It can be manufactured by making the bonding surface substantially parallel to the surface of the sheet. This graphite also has flexibility.

  In the graphite substrate according to the present invention, the surface roughness Ra of the surface facing the scintillator layer is preferably 0.10 μm ≦ Ra ≦ 0.80 μm. The surface roughness can be adjusted by sandblasting using alumina powder having a particle size of about # 4000 (average particle size of about 3.0 μm) to a particle size of about # 8000 (average particle size of about 1.2 μm). Here, “particle size” refers to a particle size defined in accordance with JIS R 6001: 1998 (particle size of abrasive for grinding wheel).

  In addition, when bonding the scintillator panel and the planar light receiving element surface, due to the influence of deformation of the substrate and warping during vapor deposition, it is not possible to obtain uniform image quality characteristics within the light receiving surface of the flat panel detector. By making the substrate into a polymer (resin) substrate having a thickness of 50 to 500 μm, the scintillator panel is deformed into a shape that matches the shape of the planar light receiving element surface, and uniform sharpness is obtained over the entire light receiving surface of the flat panel detector. can get.

(Production method of scintillator panel)
A typical example of a method for manufacturing a scintillator panel of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view when the scintillator plate is sealed with a protective layer. FIG. 2 is a diagram showing a schematic configuration of the vapor deposition apparatus 61.

  In FIG. 1, sealing is performed with a first protective layer 5 on the scintillator layer 2 surface side and a second protective layer 6 on the substrate 1 side. Between the scintillator layer on the substrate 1 side, a metal reflective layer 3 and an insulating layer 4 are provided.

<Vapor deposition equipment>
As shown in FIG. 2, the vapor deposition apparatus 61 has a box-shaped vacuum vessel 62, and a vacuum vapor deposition boat 63 is arranged inside the vacuum vessel 62. The boat 63 is a member to be filled as an evaporation source, and an electrode is connected to the boat 63. When a current flows through the electrode to the boat 63, the boat 63 generates heat due to Joule heat. At the time of manufacturing the radiation scintillator panel 10, the boat 63 is filled with a mixture containing cesium iodide and an activator compound, and an electric current flows through the boat 63 so that the mixture can be heated and evaporated. It has become.

  As the member to be filled, an alumina crucible around which a heater is wound may be applied, or a refractory metal heater may be applied.

  A holder 64 for holding the graphite sheet substrate 1 is disposed inside the vacuum vessel 62 and immediately above the boat 63. The holder 64 is provided with a heater (not shown), and the substrate 1 mounted on the holder 64 can be heated by operating the heater. When the substrate 1 is heated, the adsorbate on the surface of the substrate 1 is removed or removed, and an impurity layer is formed between the substrate 1 and the scintillator layer (phosphor layer) 2 formed on the surface. Can be prevented, the adhesion between the substrate 1 and the scintillator layer 2 formed on the surface thereof can be strengthened, and the film quality of the scintillator layer 2 formed on the surface of the substrate 1 can be adjusted. It has become.

  The holder 64 is provided with a rotating mechanism 65 that rotates the holder 64. The rotating mechanism 65 is composed of a rotating shaft 65a connected to the holder 64 and a motor (not shown) as a driving source for the rotating shaft 65. When the motor is driven, the rotating shaft 65a rotates to displace the holder 64 in the boat. It can be rotated in a state of being opposed to 63.

  In the vapor deposition apparatus 61, in addition to the above configuration, a vacuum pump 66 is disposed in the vacuum container 62. The vacuum pump 66 exhausts the inside of the vacuum vessel 62 and introduces gas into the inside of the vacuum vessel 62. By operating the vacuum pump 66, the inside of the vacuum vessel 62 has a gas atmosphere at a constant pressure. Can be maintained below.

<Scintillator panel>
Next, a method for manufacturing the scintillator panel 10 according to the present invention will be described.

  In the manufacturing method of the said scintillator panel 10 for radiation, the evaporator 61 demonstrated above can be used suitably. A method for producing the radiation scintillator panel 10 using the evaporation device 61 will be described.

<Formation of metal reflective layer>
A metal thin film (aluminum, silver) is formed as a metal thin film on one surface of the substrate by sputter deposition.

<Formation of insulating layer>
The insulating layer is formed by applying and drying a composition in which a polymer binder is dispersed and dissolved in an organic solvent. The polymer binder is preferably a hydrophobic resin such as a polyester resin or a polyurethane resin from the viewpoints of adhesion and corrosion resistance of the conductive metal reflective layer.

<Formation of scintillator layer>
The substrate 1 provided with the metal reflective layer 4 and the insulating layer 3 as described above is attached to the holder 64, and the boat 63 is filled with a powdery mixture containing cesium iodide and thallium iodide (preparation step). In this case, it is preferable that the distance between the boat 63 and the substrate 1 is set to 100 to 1500 mm, and the later-described vapor deposition process is performed within the set value range.

  When the preparation process is completed, the vacuum pump 66 is operated to evacuate the inside of the vacuum vessel 62, and the inside of the vacuum vessel 62 is brought to a vacuum atmosphere of 0.1 Pa or less (vacuum atmosphere forming step). Here, “under vacuum atmosphere” means under a pressure atmosphere of 100 Pa or less, and preferably under a pressure atmosphere of 0.1 Pa or less.

  Thereafter, an inert gas such as argon is introduced into the vacuum vessel 62, and the inside of the vacuum vessel 62 is maintained in a vacuum atmosphere of 0.1 Pa or less. Next, the heater of the holder 64 and the motor of the rotation mechanism 65 are driven, and the substrate 1 attached to the holder 64 is rotated while being heated while facing the boat 63.

  In this state, a current is passed from the electrode to the boat 63, and the mixture containing cesium iodide and thallium iodide is heated at about 700 ° C. to 800 ° C. for a predetermined time to evaporate the mixture. As a result, innumerable columnar crystals 2a are sequentially grown on the surface of the substrate 1 to form a scintillator layer 2 having a desired thickness (evaporation process). Thereby, the scintillator plate for radiation according to the present invention can be manufactured.

(Scintillator plate sealing)
The scintillator panel 1 of the present invention includes the above-described protective layer, that is, the first protective layer 5 disposed on the scintillator layer 2 side of the scintillator plate, and the second protective layer 6 disposed on the substrate 1 side of the scintillator plate. Protected from humidity, mechanical shock, etc. The first protective layer 5 and the second protective layer 6 can be manufactured by sandwiching a scintillator plate and sealing four sides. In this case, the first protective layer 5 and the second protective layer 6 may be different or the same, and can be appropriately selected as necessary.

  As described above, the protective layer according to the present invention is a polymer (resin) film, and the inner surface thereof is heat-fusible, so that it can be fused with an impulse sealer under reduced pressure.

[Protective layer]
Japanese Patent Application Laid-Open No. 2000-56694 includes a laminate in which a rubber layer is laminated on one side of a transparent film layer having a light transmittance of 80% or more, and the light transmittance of the laminate is 80% or more. A protective film for a screen is disclosed. The rubber layer is formed from any one rubber selected from the group consisting of silicone rubber, fluoro rubber, acrylic rubber, ethylene propylene rubber, and acrylonitrile butadiene rubber, or a mixture of two or more rubbers. These are suitable for the flat panel detector of the present invention.

  As the protective layer of the scintillator, the effect of the present invention can be obtained as long as it is possible to form a re-peeling pressure-sensitive adhesive layer. . The effect of the present invention can be easily achieved by sealing the scintillator with a resin film on which a re-peeling adhesive layer has been previously applied.

  Further, when a polymer film is used as the protective layer, the sharpness is lowered when the film thickness is 200 μm or more, and the durability against physical contact is insufficient when the film is 12 μm or less. The thickness of the protective film is preferably 12 to 200 μm.

〔substrate〕
Furthermore, when the scintillator panel and the planar light receiving element surface are bonded, the image quality is not uniform within the light receiving surface of the flat panel detector due to the influence of deformation of the substrate and warpage during vapor deposition. By making the substrate a polymer film having a thickness of 50 to 500 μm and making the total thickness of the scintillator panel to be 1 mm or less, the scintillator panel is deformed into a shape suitable for the planar light receiving element surface shape, and the flat panel detector Uniform sharpness can be obtained over the entire light receiving surface.

  The polymer (resin) film used as the substrate is preferably a film containing polyimide, polyethylene naphthalate, or graphite as a main component and having a thickness of 50 to 500 μm because of heat resistance during vapor deposition. .

(Flat panel detector)
The flat panel detector of the present invention has a scintillator panel comprising a scintillator plate provided with a scintillator layer on a substrate and a protective layer covering the entire surface of the scintillator layer (side) of the scintillator plate on the plane light receiving element surface. It is the structure which has been arrange | positioned.

  Hereinafter, although this embodiment is described with reference to an accompanying drawing, it is an example and is not limited to this embodiment.

  FIG. 3 is a block diagram of the flat panel detector 100 of the present invention. The flat panel detector 100 is provided in the casing 111 so as to be in pressure contact with the scintillator panel 112 and the scintillator panel 112 that receive radiation transmitted through the subject and instantaneously emit fluorescence with an intensity corresponding to the dose. A light receiving element 113 in which a plurality of light receiving pixels that photoelectrically convert light from the two-dimensionally arranged, a protective cover 114 that protects the scintillator panel 112, and a cushion layer 115 as a cushion member are provided.

  The scintillator panel 112 has a configuration in which a phosphor layer 122 is formed on a substrate 123, and the substrate 123 and the phosphor layer 122 are sealed with a first protective film 121 and a second protective film 124.

  The substrate 123 is made of a material that transmits radiation. The substrate 123 preferably has flexibility so that the scintillator panel 112 can be uniformly brought into contact with the surface of the light receiving element 113. For example, a flexible polyimide film having a thickness of 125 μm can be used. In addition to the polyimide film, a cellulose acetate film, a polyester film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polyamide film, a triacetate film, a polycarbonate film, a graphite sheet, or the like can be used. As thickness, 50-500 micrometers is preferable.

  The phosphor layer 122 is composed of a phosphor layer having a columnar crystal structure having a light guide effect and high luminous efficiency. This phosphor layer is preferably formed on the substrate by vapor deposition. For example, a phosphor layer having a columnar crystal structure can be formed on the substrate 122 by vacuum-depositing cesium iodide (CsI) to which thallium (Tl) is added as an activator as a phosphor material. In addition to cesium iodide (CsI), cesium bromide (CsBr) or the like can be used. As the activator, europium, indium, lithium, potassium, rubidium, sodium, copper, cerium, zinc, titanium, gadolinium, terbium and the like can be used in addition to thallium (Tl).

  The cushion layer 115 is for bringing the scintillator panel 112 into pressure contact with the light receiving element 113 with an appropriate pressure. For example, a silicon-based or urethane-based foam material that absorbs little radiation can be used.

  The 1st protective film 121 and the 2nd protective film 124 are for moisture-proofing the fluorescent substance layer 121 and suppressing deterioration of the fluorescent substance layer 122, and are comprised from a film with low moisture permeability. For example, a polyethylene terephthalate film (PET) can be used. Besides PET, a polyester film, a polymethacrylate film, a nitrocellulose film, a cellulose acetate film, a polypropylene film, a polyethylene naphthalate film, or the like can be used.

  The light receiving element 113 is composed of a plurality of light receiving pixels arranged two-dimensionally. For example, it can be constituted by a photodiode + a thin film transistor (TFT). The signal charge photoelectrically converted by the photodiode is read out using the TFT. In addition, a CMOS, a CCD, or the like can be used as the light receiving element 113.

  The protective cover 114 protects the scintillator panel 112 from external impacts and the like, and also plays a role of compressing the cushion layer 115 and pressing the scintillator panel 112 to the light receiving element 113 with an appropriate pressure. For example, it is composed of a carbon plate with high radiation transparency. In addition, an aluminum plate can be used as the protective cover 14.

  When assembling the flat panel detector 1, the scintillator panel 112 sealed with the first protective film 121 is placed on the light receiving element 113 arranged in the housing 111, and further, the cushion layer 115 and then the protective cover 114. Is assembled to the housing 11 with screws or the like. When the protective cover 114 is attached, the cushion layer 115 is compressed, and the scintillator panel 112 is pressed against the light receiving element 113 with an appropriate pressure by the repulsive force of the cushion layer 115 against the compression. The first protective film 121 and the light receiving element 113 are bonded to each other by this pressure, and the displacement of the scintillator panel 112 and the light receiving element 113 due to vibration, inclination of the flat panel detector, or the like is prevented.

  Further, since the substrate 123 is made of a resin film of 200 μm or less and the total thickness of the scintillator panel 112 is 1 mm or less, the scintillator panel 112 matches the surface shape of the planar light receiving element 13 with an appropriate pressure of the cushion layer 115. It is deformed to a uniform shape, and a uniform contact state is obtained over the entire light receiving surface of the flat panel detector.

  Thus, according to the present embodiment, a good adhesion state between the scintillator panel 112 and the light receiving element 113 can be obtained with an appropriate pressure of the cushion layer 115 that does not damage the phosphor layer 122. In addition, since the work should just mount the scintillator panel 112 on the light receiving element 113 and attach the cushion layer 115 and the protective cover 114, it can assemble easily with high precision.

  In the present embodiment, the two protective films of the first protective film 124 and the second protective film 121 are used. However, the protective layer is a polyparaxylylene formed on the entire surface of the scintillator panel by the CVD method other than the resin film. Even if it is a film | membrane, the effect of this invention is realizable in the same procedure.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

Example (Preparation of scintillator plate)
(Formation of metal reflective layer)
A silver thin film with a thickness of 100 nm was formed as a reflective layer on one surface of a polyimide substrate with a thickness of 125 μm by sputtering deposition.

(Formation of insulating layer)
Byron 630 (manufactured by Toyobo Co., Ltd .: polymer polyester resin) 100 parts by mass Methyl ethyl ketone (MEK) 90 parts by mass Toluene 90 parts by mass The above formulation was mixed and dispersed in a bead mill for 15 hours to obtain a coating solution for coating. This coating solution was applied to the sputtering surface of the graphite sheet substrate with a bar coater so that the dry film thickness was 1.0 μm, and then dried at 100 ° C. for 8 hours to produce an insulating layer.

(Substrate cutting)
The polyimide substrate on which the insulating layer was produced was cut according to the metal frame of the substrate holder of the vapor deposition apparatus in FIG. 2 and set on the metal frame.

(Formation of scintillator layer)
A phosphor (CsI: 0.003Tl) was deposited on the insulating layer side of the substrate using the deposition apparatus shown in FIG. 2 to form a scintillator layer (phosphor layer).

  That is, first, the phosphor raw material was filled in a resistance heating crucible (board) as an evaporation material, the substrate was placed on a metal frame of a rotating substrate holder, and the distance between the substrate and the evaporation source was adjusted to 400 mm.

  Subsequently, the inside of the vapor deposition apparatus was once evacuated, Ar gas was introduced and the degree of vacuum was adjusted to 0.5 Pa, and then the substrate temperature was maintained at 200 ° C. while rotating the substrate at a speed of 10 rpm. Next, the resistance heating crucible (board) was heated to deposit phosphor, and when the scintillator layer thickness reached 450 μm, the deposition was terminated to obtain a substrate on which the scintillator layer was formed.

(Annealing treatment)
The substrate on which the scintillator layer was formed was cut into a size of 25 cm × 20 cm, and annealed at 200 ° C. for 4 hours in a nitrogen atmosphere to obtain a scintillator plate.

(Protective film)
Table 1 shows the “material” and “flexural modulus” of the outermost layer of the first protective layer.

  Table 3 shows the composition of the composite polymer film used for the first protective layer and the second protective layer.

(Preparation of scintillator panel 1)
A resin (polymer) film configuration A is used on the scintillator layer side (first protective layer) and the base material side (second protective layer) on a scintillator plate fabricated on a 125 μm thick polyimide substrate by the method described above. A scintillator panel was produced by sealing in the form shown in FIG.

  The sealing was performed so that the distance from the fused part to the peripheral part of the scintillator sheet was 1 mm under a reduced pressure of 1000 Pa. The impulse sealer used for the fusion was a 3 mm wide heater.

  In this way, one scintillator panel having a size of 25 cm × 20 cm covered with a protective film was obtained.

(Production of scintillator panels 2 to 4)
Scintillator panels 2 to 4 were produced in the same manner as scintillator panel 1 except that the composite polymer film and the substrate shown in Table 2 were used for the first and second protective layers, respectively.

<Evaluation>
The obtained scintillator panel is set in PaxScan (FPD: 2520 manufactured by Varian). As a flat panel detector, the average light emission amount (luminance) of the entire scintillator panel and the average value of the sharpness of the entire scintillator panel are as follows: Evaluation was performed by the method shown. The results are shown in Table 1.

<Brightness evaluation method>
The FPD was irradiated with X-rays having a tube voltage of 80 kVp, and the average signal value of the obtained image data was defined as the light emission amount. In Table 2, the light emission amount of the scintillator panel 4 that was not annealed was set to a luminance of 1.0.

<Evaluation method of sharpness>
X-rays with a tube voltage of 80 kVp were irradiated to the radiation incident surface side of the FPD through a lead MTF chart, and image data was detected and recorded on a hard disk. Thereafter, the recording on the hard disk was analyzed by a computer, and the modulation transfer function MTF (MTF value at a spatial frequency of 1 cycle / mm) of the X-ray image recorded on the hard disk was used as an index of sharpness. In the table, the higher the MTF value, the better the sharpness. MTF is an abbreviation for Modulation Transfer Function.

  The MTF values in Table 1 are average values obtained by measuring 10 points in the scintillator panel.

<Evaluation method for sharpness uniformity>
The MTF uniformity was evaluated as follows for the MTF values at the 10 locations.
○: The maximum value and the minimum value at 10 locations are within ± 8% with respect to the average value Δ: Either the maximum value or the minimum value at 10 locations is within ± 8% with respect to the average value ×: 10 locations The maximum value and the minimum value are ± 8% or more and less than 13% with respect to the average value. XX: The maximum value and the minimum value at 10 locations are 13% or more with respect to the average value.

  As apparent from the results shown in Table 2, the scintillator panel according to the flat panel detector of the present invention has high scintillator light emission extraction efficiency and high sharpness, and little deterioration in sharpness between plane light receiving element surfaces. It can be seen that the scintillator panel has an improved partial sharpness reduction.

Cross-sectional view of scintillator panel sealed with protective layer Diagram showing schematic configuration of vapor deposition equipment Configuration of the flat panel detector of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Phosphor layer 3 Metal reflective layer 4 Insulating layer 5 First protective layer 6 Second protective layer 10 Scintillator panel 61 Vapor deposition apparatus 62 Vacuum vessel 63 Resistance heating crucible 64 Holder 65 Rotating mechanism 66 Vacuum pump 100 Flat panel detector 111 Case Body 113 Light-receiving element 114 Protective cover 115 Cushion layer 121 Scintillator panel 121 First protective film 122 Phosphor layer 123 Substrate 124 Second protective film

Claims (8)

In a flat panel detector in which a scintillator panel comprising a scintillator plate provided with a scintillator layer on a substrate and a protective layer covering the scintillator layer side surface of the scintillator plate is disposed on a planar light receiving element surface, the outermost layer of the protective layer A flat panel detector having a flexural modulus of 50 to 2500 MPa. The flat panel detector according to claim 1, wherein the protective layer is made of a polymer film. The flat panel detector according to claim 2, wherein the polymer film has a thickness of 12 to 200 μm. The flat panel detector according to claim 2 or 3, wherein the scintillator panel is sealed by vacuum adhesion using the polymer film. The flat panel detector according to claim 1, wherein the scintillator layer is formed by a vapor deposition method. The flat panel detector according to any one of claims 1 to 5, wherein the scintillator layer contains cesium iodide as a main component. The flat panel detector according to any one of claims 1 to 6, wherein the substrate contains polyimide, polyethylene naphthalate, or graphite as a main component and has a thickness of 50 to 500 µm. . The flat panel detector according to any one of claims 1 to 6, wherein a total thickness of the scintillator panel is 1 mm or less.

Images