JP5668691B2 - Scintillator panel, manufacturing method thereof, and radiation image detector - Google Patents

Description

  The present invention relates to a roll scintillator panel support, a scintillator panel, a method for manufacturing the same, and a radiation image detector using the scintillator panel.

  Radiation images using radiation typified by X-ray images are widely used for diagnosis of medical conditions in the medical field. As a medical radiographic imaging system, high sensitivity and high image quality have been achieved over a long history, and screen film imaging systems that combine high reliability and excellent cost performance are used in medical settings around the world. It has been.

  However, in recent years, digitization of radiographic images has been realized, and images can be directly displayed on an image display device such as a liquid crystal display. Therefore, it is not always necessary to form an image on a film. As a result, these digital radiographic image detection devices reduce the necessity of image formation by the silver halide photography method, and greatly improve the convenience of diagnosis work in hospitals and clinics.

  CR (computed radiography) using a stimulable phosphor is currently accepted in the medical field as such a digital radiation image detection apparatus. However, the sharpness is insufficient and the spatial resolution is insufficient, and the image quality level of the screen film is not reached.

  As a new technology, for example, J.A. Rowlands et al., “Amorphous Semiconductors User in Digital X-ray Imaging” Physics Today, 24-30, November (1997), L. et al. E. Antonuk et al., “Development of a High Resolution, Active Matrix, Flat-Panel Imager with Enhanced Fill Factor” SPI Vol. FPD (flat panel detector) using TFT (Thin Film Transistor) described in 3032, 2-13 (1997) and the like has been developed.

  There are two types of FPD: a direct type that converts irradiated radiation into a charge amount, and an indirect type that converts the radiation into visible light by a scintillator panel and converts it into a charge amount by a photoelectric conversion element such as a photodiode. In order to improve the S / N ratio in shooting, it is necessary to use a scintillator panel with high luminous efficiency. In general, the luminous efficiency of a scintillator panel is determined by the thickness of the phosphor layer and the X-ray absorption coefficient of the phosphor, but the thicker the phosphor layer, the more light scattering occurs in the layer, and the sharpness is descend. That is, the thickness of the phosphor layer is determined by the sharpness required for image quality.

  Among them, the cesium iodide (CsI) phosphor has a relatively high conversion rate from radiation to visible light, and can easily form a columnar crystal structure by vapor deposition. Therefore, light scattering within the crystal is suppressed by the light guide effect. It was possible to increase the thickness of the phosphor layer.

  Further, since the luminous efficiency is insufficient with CsI alone, for example, as described in Japanese Patent Publication No. 54-3560, a mixture of CsI and sodium iodide (NaI) at an arbitrary molar ratio is deposited. Used to deposit sodium-activated cesium iodide (CsI: Na) on a substrate, and in recent years, a mixture of CsI and thallium iodide (TlI) in an arbitrary molar ratio is used to deposit thallium on a substrate using vapor deposition. It is deposited as cesium iodide (CsI: Tl) and used as a scintillator panel.

  However, although the luminous efficiency of the scintillator panel is improved by these activators, the crystals themselves have a deliquescent property, and there is a drawback that the moisture resistance is remarkably lowered and the characteristics deteriorate with time. In order to prevent such deterioration with time, it has been proposed to form a moisture-proof protective layer on the surface of the CsI scintillator. The surface of such a deliquescent scintillator phosphor layer (the surface on the side not facing the substrate) is usually provided with a protective film, and the phosphor layer is chemically altered or physically impacted. Protect from.

  As this protective film, a method of forming an organic film such as polyparaxylylene by a vapor deposition method such as a CVD method is known. However, these organic film protective layers are weakly moisture-proof and sufficiently phosphor. In general, the phosphor layer and the entire support are covered with an organic film protective layer. However, when the vapor deposition method is used, a protective organic film is not formed on a portion where the vapor deposition table or the holding member is in contact. In Patent Document 1, a polyparaxylylene film is formed twice. This avoids this drawback, but the manufacturing process becomes complicated.

  There is also a technique for performing moisture-proof protection with an inorganic material on the back surface. Patent Documents 2 and 3 disclose a technique for improving the moisture resistance performance by molding a metal moisture-proof foil by pressing on the back surface, but because it is a batch process that heats and pressurizes for a certain period of time, productivity is improved. It's not expensive. Patent Document 4 has a metal layer on the surface opposite to the substrate surface having the phosphor layer, and the substrate, the phosphor layer, and the metal layer are entirely covered with a moisture-resistant protective film. A radiation scintillator plate is disclosed. However, the moisture-resistant protective film of the radiation scintillator plate has a bag shape, and requires an adhesive means and a margin for adhesion, which complicates the manufacturing process.

Japanese Patent No. 4317068 JP 2003-287571 A JP 2004-325445 A JP 2008-170314 A

  The present invention has been considered in view of the above-mentioned problems and situations, and a solution to that problem is a support for a roll scintillator panel, a scintillator panel with high productivity and improved moisture resistance without complicating the manufacturing process. And a method of manufacturing the same. Furthermore, it is providing the radiographic image detector using the said scintillator panel.

  The above-mentioned problem according to the present invention is solved by the following means.

1 . A scintillator panel having a phosphor layer that converts the radiation into light to the support is obtained by cutting the support Gallo Lumpur shaped scintillator panel support in a predetermined size, of the support A metal thin film layer having a thickness in the range of 1 to 500 nm is provided on the surface opposite to the surface having the phosphor layer, and the light emitting surface and side surface of the phosphor layer and the side surface of the support are moisture resistant. Covered with a protective film ,
Before SL phosphors used in the phosphor layer, characterized and to Resid inch regulator panel that the phosphor columnar crystals formed by vapor deposition.

2 . The scintillator panel according to item 1 , wherein the support is made of a flexible polymer film.

3 . The moisture-resistant protective film, the first term, characterized in that an organic film formed by vapor deposition or scintillator panel according to the second term.

4 . Moisture permeability of the metal thin film layer is 90% under a temperature 40 ° C. · relative humidity, according to any one of the first term of equal to or less than 50g / m2 · 24h to paragraph 3 Scintillator panel.

5 . The first to fourth items, wherein the metal thin film layer contains at least one of aluminum (Al) and silver (Ag), or contains an alloy containing aluminum or an alloy containing silver. The scintillator panel according to any one of the above.

6 . The scintillator panel according to any one of the first term and having a subbing layer comprising a polymeric material on the metal thin film layer to the fifth term.

7 . The phosphor layer, a scintillator panel according to any one of the cesium iodide, from the first term, characterized in that the additive comprising thallium formed as raw materials to paragraph 6.

8 . A method of manufacturing a scintillator panel in which a phosphor layer for converting radiation into light is provided on a support, the support being supplied in a roll-to-roll manner, and the surface of the support having the phosphor layer the metal thin film layer has a continuously formed to process, and have a step of coating a light emitting surface and the side surfaces and the support side surface of the phosphor layer with moisture-resistant protective film on the opposite side of,
Method of manufacturing a scintillator panel, characterized in that before Symbol phosphor phosphor layer is used is a phosphor columnar crystals formed by vapor deposition.

9 . 9. The method of manufacturing a scintillator panel according to claim 8 , further comprising the step of simultaneously forming the metal thin film layer and the metal reflective layer.

10 . The radiation image detector characterized by using the scintillator panel according to any one of the first term to paragraph 7.

  By the above means of the present invention, it is possible to provide a roll scintillator panel support, a scintillator panel having high productivity and improved moisture resistance without complicating the production process, and a method for producing the scintillator panel. Furthermore, a radiation image detector using the scintillator panel can be provided.

Schematic diagram of scintillator panel manufacturing equipment Diagram showing configuration (example) of scintillator panel

  The roll scintillator panel support of the present invention has a metal thin film layer having a thickness in the range of 1 to 500 nm on the support. This feature is a technical feature common to the inventions according to claims 1 to 11.

  A preferred embodiment of the scintillator panel using the roll scintillator panel support of the present invention is a scintillator panel in which a phosphor layer for converting radiation into light is provided on the support, and the support is the roll described above. The scintillator panel support is cut to a predetermined size, and a metal thin film layer having a thickness in the range of 1 to 500 nm is provided on the surface of the support opposite to the surface having the phosphor layer. And the light emission surface and side surface of the said fluorescent substance layer, and the side surface of the said support body are scintillator panels of the aspect covered with the moisture-resistant protective film.

  In the scintillator panel, the support is preferably made of a flexible polymer film from the viewpoint of manifesting the effects of the invention. The moisture-resistant protective film is preferably an organic film formed by a vapor deposition method.

In the scintillator panel, the moisture permeability of the metal thin film layer is preferably 50 g / m ² · 24 h or less at a temperature of 40 ° C. and a relative humidity of 90%. The metal thin film layer preferably contains at least one of aluminum (Al) and silver (Ag), or contains an alloy containing aluminum or an alloy containing silver. Furthermore, it is preferable to have an undercoat layer made of a polymer material on the metal thin film layer.

  The phosphor layer of the scintillator panel is preferably formed using cesium iodide and an additive containing thallium as raw materials.

  As a manufacturing method for manufacturing the scintillator panel of the present invention, the support is supplied in a roll-to-roll manner, and the metal thin film is formed on the surface of the support opposite to the surface having the phosphor layer. It is preferable that the production method has a step of continuously forming a layer and a step of covering the light emitting surface and side surface of the phosphor layer and the side surface of the support with a moisture-resistant protective film. Further, the manufacturing method preferably includes a step of simultaneously forming the metal thin film layer and the metal reflective layer.

  The scintillator panel of the present invention can be suitably used for a radiation image detector.

  Hereinafter, the present invention, its components, and the best mode and mode for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

(Configuration of scintillator panel)
The scintillator panel of the present invention can take various configurations, but basically, a support, a phosphor layer formed thereon, and the opposite side of the surface of the support having the phosphor layer. And a moisture-resistant protective film covering the light emitting surface and side surface of the phosphor layer and the side surface of the support. In addition, it is more preferable to set it as the structure which has an undercoat layer between a support body and a fluorescent substance layer. Moreover, a metal reflective layer may be provided on a support body, and the structure of a metal reflective layer, an undercoat layer, and a fluorescent substance layer may be sufficient. Compared with the configuration of the first embodiment of Patent Document 4, the metal layer described in Patent Document 4 has a columnar structure for scattering X-ray absorption and has a thickness of 5 μm or more. The invention is completely different from the present invention, which has a technical idea different from that of the present invention aiming at both simplification of the manufacturing process and moisture prevention.

  In the present application, the “scintillator” refers to a phosphor that emits light by excitation of atoms when irradiated with ionizing radiation such as α rays, γ rays, and X rays. That is, it refers to a phosphor that converts radiation into ultraviolet / visible light and emits it.

  Hereinafter, each component will be described.

(Roll scintillator panel support)
The roll scintillator panel support of the present invention has a metal thin film layer having a thickness in the range of 1 to 500 nm on the support.

  The support that can be used for the roll scintillator panel support is not particularly limited as long as it is a material that can be stored in a roll form before and after the manufacturing process or in the manufacturing process. Considering the variety of vessels, the following various polymer materials are preferable in that they are lightweight and can be easily processed.

  Therefore, as a support that can be used in the present invention, polyethylene terephthalate, polyethylene naphthalate, cellulose acetate, polyamide, polyimide, polyetherimide, epoxy, polyamideimide, bismaleimide, fluororesin, acrylic, polyurethane, polycarbonate, Polymer films such as polyphenylene sulfide, polyether sulfone, polysulfone, polyether ether ketone, and liquid crystal polymer are preferably used.

  Furthermore, the polymer film used for the support of the present invention preferably has a glass transition point of not less than 100 ° C. in order to prevent deformation due to heat when the phosphor is deposited. Therefore, from the viewpoint of heat resistance, those containing polyimide, polyetherimide, polyethylene naphthalate, polyethersulfone, polysulfone, liquid crystal polymer or the like as a main component are preferred, and polyimide is most preferred.

  As thickness of a support body, Preferably it is 20-1000 micrometers, More preferably, it is 50-750 micrometers, More preferably, it is 50-500 micrometers. By making the thickness of the support 50 μm or more, the handling property after forming the phosphor layer is improved. In addition, by making the thickness of the support 750 μm or less, it becomes easy to process the metal reflective layer, the undercoat layer, etc. by so-called roll to roll, from the viewpoint of improving productivity. Is very useful. Furthermore, when the scintillator panel and the photoelectric conversion element are bonded together, it is affected by deformation of the support or warpage during vapor deposition, and the uniform image quality characteristics cannot be obtained within the light receiving surface of the photoelectric conversion element. By setting the support to a thickness of 50 to 500 μm, the scintillator panel is deformed into a shape that matches the surface shape of the photoelectric conversion element, and uniform sharpness is obtained over the entire light receiving surface of the photoelectric conversion element.

The support according to the present invention is preferably a polymer film having flexibility. Here, the “polymer film having flexibility” means a support having an elastic modulus (E120) at 120 ° C. of 1000 to 6000 N / mm ² , and contains polyimide or polyethylene naphthalate as the support. A polymer film is preferred.

“Elastic modulus” is a tensile tester and is used to obtain the slope of the stress relative to the strain amount in a region where the strain indicated by the standard line of the sample conforming to JIS C 2318 and the corresponding stress have a linear relationship. It is a thing. This is a value called Young's modulus, and in the present invention, this Young's modulus is defined as an elastic modulus. Support for use in the present invention has an elastic modulus at 120 ° C. as described above (E120) is preferably a 1000~6000N / mm ^2, further preferably 1200~5000N / mm ^2.

Specifically, polyethylene naphthalate ^{(E120 = 4100N / mm 2)} , polyethylene terephthalate ^{(E120 = 1500N / mm 2)} , polybutylene naphthalate ^{(E120 = 1600N / mm 2)} , polycarbonate (E120 = 1700N / ^mm 2) , Syndiotactic polystyrene (E120 = 2200 N / mm ² ), polyetherimide (E120 = 1900 N / mm ² ), polyimide (E120 = 1200 N / mm ² ), polyarylate (E120 = 1700 N / mm ² ), polysulfone (E120) = 1800 N / mm ² ), polyethersulfone (E120 = 1700 N / mm ² ) and the like.

  These may be used singly or may be laminated or mixed. Among them, as a particularly preferable support, a polymer film containing polyimide or polyethylene naphthalate is preferable as described above.

(Metal thin film layer)
The scintillator panel of the present invention is characterized in that a metal thin film layer having a thickness in the range of 1 to 500 nm is provided on the surface of the support opposite to the surface having the phosphor layer. If the thickness is less than 1 nm, a uniform film cannot be formed, and sufficient moisture resistance cannot be obtained. On the other hand, if the thickness is greater than 500 nm, cracks are likely to occur, which is not preferable from the viewpoint of extending the film formation time and material cost. The metal thin film layer is provided mainly for improving moisture resistance, but is preferably formed taking into consideration the productivity improvement of the scintillator panel. For this reason, it is preferable that the said metal thin film layer is formed by the continuous formation method, moving a support body. Specifically, in the continuous forming method, a support is supplied in a “roll to roll” manner, and the metal thin film layer is continuously formed on the support by a sputtering method. It is preferable that it is the method of the aspect to do. When formed by a sputtering method, moisture resistance can be expected with a thin film as compared with a metal foil or the like.

  Examples of the metal to be contained in the metal thin film layer include various metals formed by sputtering, including Al, Ag, Cr, Cu, Ni, Ti, Mg, Rh, Pt, Au, Pd, In, and Zn. , Sn, Ru, Os, Ir, Si, alloys thereof, oxides thereof, and the like. From the viewpoint of reflectivity, corrosion resistance, cost, etc., it is preferable that at least one of aluminum (Al) or silver (Ag) is contained, and an alloy of these and the above metal is selected. In addition, the surface of the metal thin film layer of the present invention can be subjected to some chemical treatment in order to improve the corrosion resistance and handleability.

  As the method for forming the metal thin film layer, various conventionally known methods can be adopted. As described above, the support is supplied by the “roll to roll” method, and the support is supported. It is preferable that the metal thin film layer is continuously formed by a sputtering method.

  Two or more such metal thin films may be formed. When the metal thin film has two or more layers, it is preferable that the lower layer is a layer containing Ni, Cr, or both from the viewpoint of improving the adhesion to the support.

(Metal reflective layer)
In the present invention, it is also a preferable configuration aspect to provide a metal reflective layer on the support. The metal reflection layer is for reflecting the light emitted from the phosphor layer to increase the light extraction efficiency. The surface reflectance of the metal reflective layer is preferably 80% or more, more preferably 90% or more. The metal reflective layer is preferably formed of a material containing any element selected from the element group consisting of Al, Ag, Cr, Cu, Ni, Ti, Mg, Rh, Pt, and Au.

Among them, it is particularly preferable that Al or Ag is a main component from the viewpoint of reflectance and corrosion resistance, and two or more such metal thin films may be formed. When the metal thin film has two or more layers, the lower layer is preferably a layer containing Ni, Cr, or both from the viewpoint of improving the adhesion to the support. Further, a layer made of a metal oxide such as SiO ₂ or TiO ₂ may be provided in this order on the metal thin film to further improve the reflectance. In addition, it is preferable from a viewpoint of emitted light extraction efficiency that the thickness of a metal reflective layer is 0.005-0.3 micrometer, More preferably, it is 0.01-0.2 micrometer.

  The method for forming the metal reflective layer according to the present invention may be any known method such as vapor deposition, sputtering, and bonding of metal foil, but sputtering is preferred from the viewpoint of adhesion. Furthermore, when the metal thin film layer in the present invention is formed by the sputtering method, it is preferable for simplification of the process that the metal thin film layer and the metal reflective layer are simultaneously formed by the sputtering method.

  Various types of films in which an Al film is formed on a polymer film are available on the market, and these can be used as the substrate of the present invention.

(Underlayer)
In the present invention, it is preferable to provide an undercoat layer from the viewpoint of attaching a film between the support and the phosphor layer or between the metal reflective layer and the phosphor layer. The undercoat layer preferably contains a polymer material, a dispersant and the like. The thickness of the undercoat layer is preferably 0.5 to 4 μm, and if it is 4 μm or less, light scattering in the undercoat layer is reduced and the sharpness is good.

  The undercoat layer according to the present invention is preferably formed by applying and drying a polymer material dissolved or dispersed in a solvent. Specific examples of the polymer material include polyurethane, vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer. Coalescence, polyamide resin, polyvinyl butyral, polyester, cellulose derivative (nitrocellulose, etc.), styrene-butadiene copolymer, various synthetic rubber resins, phenol resin, epoxy resin, urea resin, melamine resin, phenoxy resin, silicone resin, Examples thereof include acrylic resins and urea formamide resins. Of these, polyurethane, polyester, vinyl chloride copolymer, polyvinyl butyral, and nitrocellulose are preferably used.

  As the polymer material according to the present invention, polyurethane, polyester, vinyl chloride copolymer, polyvinyl butyral, nitrocellulose and the like are particularly preferable in terms of adhesion to the phosphor layer. Moreover, it is preferable at a point with a film | membrane that a glass transition point (Tg) is a polymer of 30-100 degreeC. From this viewpoint, polyester is particularly preferable.

  Solvents that can be used to prepare the undercoat layer include lower alcohols such as methanol, ethanol, n-propanol and n-butanol, hydrocarbons containing chlorine atoms such as methylene chloride and ethylene chloride, acetone, methyl ethyl ketone, and methyl isobutyl ketone. Such as ketones, toluene, benzene, cyclohexane, cyclohexanone, xylene and other aromatic compounds, methyl acetate, ethyl acetate, butyl acetate and other lower fatty acid and lower alcohol esters, dioxane, ethylene glycol monoethyl ester, ethylene glycol monomethyl ester And ethers thereof and mixtures thereof. The undercoat layer according to the present invention may contain a pigment or a dye in order to prevent scattering of light emitted from the phosphor layer and improve sharpness and the like.

(Phosphor layer)
For the phosphor layer according to the present invention, various phosphors conventionally used as scintillators can be used. As the phosphor, those formed by various manufacturing methods can be used. In the present invention, it is preferable to use a columnar crystal phosphor formed by a vapor deposition method.

  For example, cesium halides such as cesium iodide (CsI) and cesium bromide (CsBr) can be formed as a main component, but a phosphor layer mainly including CsI is preferable. Since CsI has a relatively high conversion efficiency from radiation to visible light and can easily form a columnar crystal structure by vapor deposition, light scattering within the crystal can be suppressed by the light guide effect, and the phosphor layer can be thickened. Is possible.

  However, since CsI alone is insufficient in luminous efficiency, various activators are preferably added. For example, as mentioned in Japanese Patent Publication No. 54-35060, a mixture of CsI and sodium iodide (NaI) at an arbitrary molar ratio can be mentioned. Further, as disclosed in, for example, JP-A-2001-59899, thallium (Tl), europium (Eu), indium (In), lithium (Li), potassium (K), rubidium (Rb), sodium ( CsI containing an activator such as Na) is preferred. In the present invention, Tl and Eu are particularly preferable, and Tl is more preferable.

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

As the one or more kinds of Tl compounds according to the present invention, various Tl compounds (compounds having oxidation numbers of + I and + III) can be used, such as thallium iodide (TlI), thallium bromide (TlBr), and thallium chloride. (TlCl) or thallium fluoride (TlF, TlF ₃ ) and the like can be mentioned, and TlI is particularly preferable.

  Moreover, it is preferable that melting | fusing point of the Tl compound concerning this invention exists in the range of 400-700 degreeC. If it exceeds 700 ° C., the Tl compound in the columnar crystal is present non-uniformly, and the luminous efficiency is lowered. In the present invention, the melting point is a melting point at normal temperature and pressure.

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

  Here, when the activator is 0.001 mol% or more with respect to the phosphor, the emission luminance obtained by using cesium iodide alone is improved, which is preferable in obtaining the desired emission luminance. Moreover, it is preferable that it is 50 mol% or less because the properties and functions of cesium iodide can be maintained.

  In addition, it is preferable that the thickness of a fluorescent substance layer is 100-800 micrometers, and it is more preferable that it is 120-700 micrometers from the point from which the characteristic of a brightness | luminance and sharpness is acquired with sufficient balance.

  The phosphor according to the present invention forms a columnar crystal structure by a vapor deposition method. As the vapor deposition method, vapor deposition, sputtering, CVD, ion plating, or the like can be used. In the present invention, vapor deposition is particularly preferable.

(Moisture resistant protective film)
The scintillator panel of the present invention is characterized in that the light emitting surface and the side surface of the phosphor layer and the side surface of the support are covered with a moisture-resistant protective film.

  The moisture-resistant protective film focuses on protecting the phosphor layer. That is, cesium iodide (CsI) has a high hygroscopic property, and if it is left exposed, it absorbs water vapor in the air and deliquesces, so its main purpose is to prevent this.

  The moisture-resistant protective film can be formed using various materials. In the present invention, it is preferable to form a polyparaxylylene film by a vapor deposition method. That is, a polyparaxylylene film can be formed on the light emitting surface and side surface of the phosphor layer and the side surface of the support to form a protective layer. In addition, when a polyparaxylylene film is formed by the CVD method on this patent composition layered in the order of a metal thin film layer, a support, a metal reflection layer, an undercoat layer, and a phosphor layer, the phosphor layer surface Some of the polyparaxylylene films may wrap around the side surfaces from the metal thin film layer to the metal thin film layer surface. The support in the present invention is made of a polymer film, has a high affinity with the organic film of the moisture-resistant protective film, and has little concern about peeling off the moisture-resistant and moisture-resistant protective film. The polyparaxylylene film preferably has a thickness of 1 to 50 μm, more preferably 3 to 30 μm, from the balance of moisture permeability and sharpness.

The moisture permeability of the moisture-resistant protective film is preferably 50 g / m ² · 24 h or less, more preferably 10 g / m ² · 24 h or less in consideration of the protective property of the phosphor layer, deliquescence, etc., but 0.01 g / m ^Since a polymer film having a water vapor transmission rate of ² · day or less is difficult to obtain industrially, it is preferably 0.01 g / m ² · 24 h or more, 50 g / m ² · 24 h or less, more preferably 0.1 g / M ² · day or more and 10 g / m ² · 24 h or less are preferable. The moisture permeability is measured according to JIS Z0208 in an environment of 40 ° C. and 90% RH.

(Rigid plate)
The scintillator panel of the present invention may use a rigid plate as a component. The rigid plate according to the present invention refers to a plate having an elastic modulus of 10 GPa or more. If the difference from the coefficient of thermal expansion of the circuit board described later is ± 0 to 4.0 ppm, there can be used any metal, glass, carbon, composite material and the like without any particular limitation. By controlling the thermal expansion coefficient within this range, the dimensional change in the in-plane direction of the phosphor layer due to temperature fluctuation can be brought closer to the photoelectric conversion element, and as a result, image shift due to temperature fluctuation can be suppressed. .

(Adhesive layer)
In the present invention, it is preferable to provide a rigid plate on the surface of the support opposite to the phosphor layer forming surface, and the support and the rigid plate are preferably joined via an adhesive layer.

  The thickness of the adhesive layer is preferably 1 μm or more, more preferably 10 μm or more in consideration of the adhesive force between the support and the rigid plate. On the other hand, in order for the rigid plate to effectively suppress the dimensional change in the in-plane direction of the support due to temperature fluctuation, the thinner the adhesive layer, the better. The thickness is preferably 100 μm or less, more preferably 60 μm or less.

  In the present invention, the material for joining the support and the rigid plate is not particularly limited, but it is preferably performed via a hot melt sheet. The hot melt sheet refers to a hot melt adhesive formed in a sheet shape. A hot-melt adhesive is an adhesive mainly composed of a thermoplastic resin and is solid at room temperature and liquefied by being heated and melted. Bonding is formed by liquefying the hot melt adhesive and bonding the joining members together, further cooling and solidifying the hot melt adhesive.

  In the present embodiment, the support and the rigid plate are joined by sandwiching a hot melt sheet between the support and the rigid plate, pressurizing, and then heating and melting. Thus, since the hot melt adhesive does not produce an adhesive force at room temperature, by using a hot melt sheet for bonding the support and the rigid plate, compared to a room temperature pressure sensitive adhesive such as a double-sided pressure sensitive adhesive tape, Alignment is very easy. That is, positioning is performed in a state where no adhesive force is generated, and then heating and melting are performed to generate an adhesive force and bonding is performed. Therefore, the support and the rigid plate can be accurately and easily aligned.

  Further, the hot melt sheet has a higher elastic modulus than a general room temperature pressure-sensitive adhesive sheet, and has a high effect of suppressing dimensional changes in the in-plane direction of the support with respect to temperature fluctuations.

  Known hot melt sheets can be used. Moreover, as a kind of hot-melt sheet, polyolefin type, polyamide type, polyester type, polyurethane type, EVA type etc. are mentioned by the main component, for example. However, it is not limited to these.

  As a pressure at the time of bonding a hot-melt sheet, 0.001-10 MPa is preferable and it is more preferable if it is 0.01-1 MPa. By making the amount of pressurization at least 0.001 MPa or more, air can be uniformly adhered without accumulating. On the other hand, by making the amount of pressurization at least 10 MPa or less, damage to the phosphor can be suppressed, and there is little fear of impairing the image quality. The heat treatment temperature is preferably 70 to 200 ° C., more preferably 90 to 160 ° C., although it depends on the type of hot melt sheet.

(Manufacturing method of scintillator panel)
As a method for producing the scintillator panel of the present invention, various conventionally known methods can be adopted. However, the support is supplied in a “roll to roll” manner, and the phosphor layer of the support is supplied. A step of continuously forming the metal thin film layer on a surface opposite to the surface having a surface by a sputtering method, and the light emitting surface and the side surface of the phosphor layer and the side surface of the support are covered with a moisture-resistant protective film. It is preferable that it is a manufacturing method of the aspect which has the process to coat | cover.

  Here, the “roll to roll” method refers to a method in which a substrate such as a roll-shaped support is supplied and continuously processed without being cut (cut).

  The scintillator panel manufacturing method according to the present invention uses a vapor deposition apparatus having an evaporation source and a support rotation mechanism in a vacuum vessel, and installs the support on the support rotation mechanism, and rotates the support. However, it is preferable that the phosphor layer is formed by a vapor deposition method including a step of vapor-depositing the phosphor material.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG.

<Scintillator panel manufacturing equipment>
FIG. 1 is a schematic configuration diagram of a scintillator panel manufacturing apparatus 1 according to the present invention. As shown in FIG. 1, the scintillator panel manufacturing apparatus 1 includes a vacuum container 2, and the vacuum container 2 includes a vacuum pump 3 that exhausts the inside of the vacuum container 2 and introduces the atmosphere.

  A support holder 5 that holds the support 4 is provided in the vicinity of the upper surface inside the vacuum vessel 2.

  A phosphor layer is formed on the surface of the support 4 by a vapor deposition method. As the vapor deposition method, a vapor deposition method, a sputtering method, a CVD method, an ion plating method, or the like can be used. In the present invention, the vapor deposition method is particularly preferable.

  The support holder 5 is configured to hold the support 4 so that the surface of the support 4 on which the phosphor layer is formed faces the bottom surface of the vacuum vessel 2 and is parallel to the bottom surface of the vacuum vessel 2. It has become.

  The support holder 5 is preferably provided with a heater (not shown) for heating the support 4. By heating the support 4 with this heater, the adhesion of the support 4 to the support holder 5 is enhanced and the film quality of the phosphor layer is adjusted. Further, the adsorbate on the surface of the support 4 is removed and removed, and an impurity layer is prevented from being generated between the surface of the support 4 and the phosphor.

  Moreover, you may have a mechanism (not shown) for circulating a heating medium or a heating medium as a heating means. This means is suitable for the case where vapor deposition is performed while keeping the temperature of the support 4 at a relatively low temperature of 50 to 150 ° C. during the vapor deposition of the phosphor.

  Moreover, you may have a halogen lamp (not shown) as a heating means. This means is suitable for the case where vapor deposition is performed while keeping the temperature of the support 4 at a relatively high temperature such as 150 ° C. or higher during vapor deposition of the phosphor.

  Further, the support holder 5 is provided with a support rotating mechanism 6 that rotates the support 4 in the horizontal direction. The support rotating mechanism 6 supports the support holder 5 and rotates the support 4 and a motor (not shown) that is disposed outside the vacuum vessel 2 and serves as a drive source for the support rotating shaft 7. Z).

  Further, near the bottom surface inside the vacuum vessel 2, evaporation sources 8 a and 8 b are arranged at positions facing each other on the circumference of a circle centering on a center line perpendicular to the support 4. In this case, the distance between the support 4 and the evaporation sources 8a and 8b is preferably 100 to 1500 mm, and more preferably 200 to 1000 mm. The distance between the center line perpendicular to the support 4 and the evaporation sources 8a and 8b is preferably 100 to 1500 mm, more preferably 200 to 1000 mm.

  In the scintillator panel manufacturing apparatus according to the present invention, it is possible to provide a large number of three or more evaporation sources, and the respective evaporation sources may be arranged at equal intervals or at different intervals. Good. Further, the radius of a circle centered on the center line perpendicular to the support 4 can be arbitrarily determined.

  The evaporation sources 8a and 8b contain the phosphor and heat it by a resistance heating method. Therefore, the evaporation sources 8a and 8b may be composed of an alumina crucible wound with a heater, a boat or a heater made of a refractory metal. May be. Further, the method of heating the phosphor may be a method such as heating by an electron beam or heating by high frequency induction other than the resistance heating method, but in the present invention, it is relatively easy to handle, inexpensive, and In view of the fact that it can be applied to a large number of substances, a method in which a direct current is passed and resistance heating is performed, and a method in which a crucible is indirectly resistance heated with a surrounding heater is preferable. The evaporation sources 8a and 8b may be molecular beam sources by a molecular source epitaxial method.

  Further, a shutter 9 that blocks the space from the evaporation sources 8a and 8b to the support 4 is provided between the evaporation sources 8a and 8b and the support 4 so as to be openable and closable in the horizontal direction. In the evaporation sources 8a and 8b, substances other than the target substance attached to the surface of the phosphor can be prevented from evaporating at the initial stage of vapor deposition and adhering to the support 4.

<Manufacturing method of scintillator panel>
Next, the manufacturing method of the scintillator panel of this invention using the above-mentioned scintillator panel manufacturing apparatus 1 is demonstrated.

  First, the support 4 is attached to the support holder 5. Further, in the vicinity of the bottom surface of the vacuum vessel 2, the evaporation sources 8 a and 8 b are arranged on the circumference of a circle centering on the center line perpendicular to the support 4. In this case, the distance between the support 4 and the evaporation sources 8a and 8b is preferably 100 to 1500 mm, and more preferably 200 to 1000 mm. The distance between the center line perpendicular to the support 4 and the evaporation sources 8a and 8b is preferably 100 to 1500 mm, more preferably 200 to 1000 mm.

Next, the inside of the vacuum vessel 2 is evacuated to a medium vacuum degree of about 1 × 10 ^{−2 to} 10 Pa. Preferably, the degree of vacuum is 1 × 10 ^{−2 to} 1 Pa. More preferably, after exhausting the inside of the apparatus to a high vacuum degree of about 1 × 10 ⁻⁵ to 1 × 10 ⁻² Pa, an inert gas such as Ar gas, Ne gas, N ₂ gas is introduced to Use a medium vacuum.

  Thereafter, the support holder 5 is rotated with respect to the evaporation sources 8 a and 8 b by the support rotation mechanism 6, the phosphor is evaporated from the heated evaporation sources 8 a and 8 b, and the phosphor is placed on the surface of the support 4. Grow to desired thickness. Thereby, the water pressure, oxygen partial pressure, etc. in the apparatus can be lowered. As the exhaust device, a rotary pump, a turbo molecular pump, a cryopump, a diffusion pump, a mechanical booster, or the like can be used in appropriate combination.

  The phosphor layer may be formed by performing the process of growing the phosphor on the surface of the support 4 in a plurality of times.

  In the vapor deposition method, the vapor-deposited body (support 4, protective layer, or intermediate layer) may be cooled or heated as necessary during vapor deposition.

Further, after the vapor deposition, the phosphor layer may be heat-treated. In the vapor deposition method, reactive vapor deposition may be performed in which vapor deposition is performed by introducing a gas such as O ₂ or H ₂ as necessary.

  The thickness of the phosphor layer to be formed is 50 to 2000 μm, preferably 50 to 1000 μm from the viewpoint of obtaining the effects of the present invention, although it varies depending on the purpose of use of the radiation image conversion panel and the kind of the phosphor. More preferably, it is 100-800 micrometers.

  Moreover, it is preferable to set the temperature of the support body 4 in which the said phosphor layer is formed to room temperature (rt) -300 degreeC, More preferably, it is 50-250 degreeC.

  After the phosphor layer is formed as described above, the phosphor layer is physically or chemically protected on the surface of the phosphor layer opposite to the support 4 as necessary. A protective layer may be provided. The protective layer may be formed by directly applying a coating solution for the protective layer to the surface of the phosphor layer, or a protective layer separately formed in advance may be adhered to the phosphor layer. The thickness of these protective layers is preferably 0.1 μm to 2000 μm.

The protective layer may be formed by laminating inorganic substances such as SiC, SiO ₂ , SiN, and Al ₂ O ₃ by vapor deposition, sputtering, or the like.

  In the present invention, it is preferable to provide the above various functional layers in addition to the protective layer.

  According to the scintillator panel manufacturing apparatus 1 or the manufacturing method described above, by providing the plurality of evaporation sources 8 a and 8 b, the overlapping portions of the vapor sources 8 a and 8 b are rectified and deposited on the surface of the support 4. The crystallinity of the phosphor can be made uniform. At this time, as the number of evaporation sources is increased, the vapor flow is rectified at more locations, so that the crystallinity of the phosphor can be made uniform in a wider range. Further, by disposing the evaporation sources 8a and 8b on the circumference of a circle having a center line perpendicular to the support 4 as a center, the effect that the crystallinity becomes uniform due to the rectification of the vapor flow is provided. Can be obtained isotropically on the surface.

  Further, the phosphor can be uniformly deposited on the surface of the support 4 by performing the vapor deposition of the phosphor while rotating the support 4 by the support rotating mechanism 6.

  As described above, according to the scintillator panel manufacturing apparatus 1 or the manufacturing method according to the present invention, by growing the phosphor layer on the surface of the support 4 so that the crystallinity of the phosphor is uniform, Sensitivity unevenness of the phosphor layer can be reduced, and the sharpness of the radiographic image obtained from the radiographic image conversion panel using the scintillator panel according to the present invention can be improved.

  Further, by limiting the incident angle of the phosphor deposited on the support 4 to a predetermined range to prevent variations in the incident angle of the stimulable phosphor, the crystallinity of the phosphor is made more uniform, and the radiation image The sharpness of the radiation image obtained from the conversion panel can be improved.

  In addition, although the above demonstrated the case where the support body holder 5 was equipped with the support body rotation mechanism 6, this invention is not necessarily restricted to this, It vapor-deposits in the state which the support body holder 5 hold | maintained the support body 4 and was still. The present invention is also applicable to the case where the phosphor from the evaporation sources 8a and 8b is deposited by moving the support 4 in the horizontal direction with respect to the evaporation sources 8a and 8b.

(Cutting)
In the present invention, after the phosphor layer is deposited, the phosphor layer and the support can be cut into a predetermined size. The scintillator panel of the present invention is characterized in that it can be cut in such a manner that the support, the phosphor layer, and the metal thin film layer all have the same size in the plane direction.

  As a method of depositing a phosphor layer on a support and cutting it to a predetermined size, there are punching cutting using an apparatus disclosed in JP-A-2-58000, and further cutting by laser light.

There are no particular limitations on the laser that can be used for cutting with laser light. For example, Nd: YAG, Nd: glass, Nd: YLF, Nd: BEL, Nd: YVO ₄ , LNP, Ti: sapphire, alexandrite, Co MgF _2, Cr-GSGG, Emerald, Prof Sky DOO, Er-YLF, Er- infrared laser such as glass, _{ruby, He-Ne, CO 2,} Ar ion, He-Cd, Cu, Au , Sr, Kr ion , Ne ion, Xe ion, CO, hydrogen halide, O ₂ -I, Dye, Nd: visible light laser such as second harmonic and third harmonic of YAG, ArF excimer, KrF excimer, XeF excimer, UV light such as ArCl excimer, KrCl excimer, XeCl excimer, N ₂ , Au, Nd: YAG fourth harmonic Among them, a YAG-UV laser is preferable.

(Radiation image detector)
The radiation image detector using the scintillator panel of the present invention is a photoelectric conversion device such as a photodiode in a scintillator panel in which a phosphor layer is provided by vapor phase deposition on a support through a functional layer such as a metal reflection layer. A radiographic image detector may be formed by adhering or closely adhering a photoelectric conversion element in which two-dimensionally arranged pixels including an element and a TFT (Thin Film Transistor) or a CCD (Charge Coupled Devices) are arranged.

  That is, the radiographic image detector of the present invention needs to be a radiographic image detector having a phosphor layer and a photoelectric conversion element in which a plurality of light receiving pixels are arranged two-dimensionally as a basic configuration. As a result, the photoelectric conversion element converts the light emitted from the phosphor layer into electric charges, whereby the image can be converted into digital data.

  In addition, it is preferable that the surface average roughness (Ra) of the outermost surface facing the fluorescent substance layer of the photoelectric conversion element which concerns on this invention is 0.001-0.5 micrometer. For this reason, after forming a photoelectric conversion element on the glass surface, an organic resin film such as polyester or acrylic is formed on the surface, and the surface roughness is controlled by a photoetching method so that the requirements can be adjusted. preferable. The surface average roughness (Ra) of the photoelectric conversion element is preferably 0.001 to 0.1 μm, and more preferably 0.001 to 0.05 μm.

  The radiation image detector of the present invention is preferably in a mode in which the scintillator panel is pressed and adhered to the photoelectric conversion element by an elastic member (for example, sponge, spring, etc.). In addition, it is also preferable that the scintillator panel is in an embodiment in which the scintillator panel is in close contact with the solid photoelectric conversion element by reducing the gas in the gap between the scintillator panel and the solid photoelectric conversion element, and the periphery is sealed with a close seal member. . The close seal member is preferably an ultraviolet curable resin.

  Furthermore, it is also preferable that the scintillator panel has a phosphor layer, and the phosphor layer is in direct contact with the light receiving element.

  There is no restriction | limiting in particular as ultraviolet curable resin, It can select and use suitably from what is used conventionally. This ultraviolet curable resin contains a photopolymerizable prepolymer, a photopolymerizable monomer, a photopolymerization initiator or a photosensitizer.

  Examples of the photopolymerizable prepolymer include polyester acrylate, epoxy acrylate, urethane acrylate, and polyol acrylate. These photopolymerizable prepolymers may be used alone or in combination of two or more. Examples of the photopolymerizable monomer include polymethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, Examples include dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and neopentyl glycol di (meth) acrylate.

  In the present invention, it is preferable to use urethane acrylate as the prepolymer and dipentaerythritol hexa (meth) acrylate as the monomer.

  Examples of the photopolymerization initiator include acetophenones, benzophenones, α-amyloxime esters, tetramethylchuram monosulfide, thioxanthones, and the like. Further, n-butylamine, triethylamine, poly-n-butylphosphine and the like can be mixed and used as a photosensitizer.

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

(Preparation of a roll-shaped support having an undercoat layer and a metal reflective layer)
A 125 μm thick, 1 m wide, 100 m long polyimide film (Ube Industries Upilex S) is supplied in a roll-to-roll manner, and then silver is sputtered to a thickness of 70 nm (700 mm). Then, a metal reflection layer was formed, and at the same time, Al was sputtered to a thickness shown in Table 1 on the opposite surface of the polyimide film on which silver was sputtered to form a metal thin film layer. Subsequently, a polyester resin dissolved in methyl ethyl ketone (Byonbo Byron 200) was applied using a gravure coater and dried to provide an undercoat layer of 3.0 μm (dry film thickness). Then, the support body in which the metal thin film layer, the metal reflection layer, and the undercoat layer were formed by cutting was produced.

The moisture permeability (measured according to JIS Z0208) of each metal thin film layer was 50 g / m ² · 24 h or less at a temperature of 40 ° C. and a relative humidity of 90%.

(Formation of phosphor layer)
A phosphor (CsI: 0.003 Tl; a ratio of 0.003 mol of Tl to 1 mol of CsI) was vapor-deposited on the surface of the support using a vapor deposition apparatus to form a phosphor layer. That is, the phosphor material (CsI and TlI) is filled in a resistance heating crucible (boat) as an evaporation material, and a support is placed on a metal frame of a rotating substrate holder, and the distance between the support and the evaporation source is set. 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 support temperature was maintained at 200 ° C. while rotating the substrate at a speed of 10 rpm. Next, the resistance heating crucible (boat) was heated to deposit a phosphor, and when the thickness reached 350 μm, the deposition was terminated to obtain a support on which the phosphor layer was formed.

(Preparation of moisture-resistant protective film)
The support on which the phosphor layer is formed is placed in a vapor deposition chamber of a CVD apparatus, and exposed to the vapor in which the polyparaxylylene raw material is sublimated, so that the phosphor layer surface, the phosphor layer, and the support A scintillator panel having a side coated with a polyparaxylylene film having a thickness of 10 μm was obtained.

  According to the present invention, the moisture-proof protective film is provided on the side opposite to the phosphor layer-forming surface of the support because the moisture-proof performance has already been obtained by the metal thin film layer formed by the roll-to-roll method by sputtering. There is no need to form it on the opposite side of the phosphor layer forming surface. That is, after forming a moisture-resistant protective film on the phosphor-forming surface, turn it over and again form a moisture-resistant protective film, or form a moisture-resistant protective film again on the support holding portion where the moisture-resistant protective film was not formed. Furthermore, since it is not necessary to produce a bag-like moisture-resistant protective film as disclosed in Patent Document 4 and enclose and bond it, the manufacturing process can be simplified. Further, in the scintillator panel of the present invention, it is possible to perform cutting in such a manner that the sizes of the support, the phosphor layer, and the metal thin film layer in the planar direction are all the same.

  Hereinafter, the obtained scintillator panel was evaluated.

<Sharpness>
X-ray with tube voltage of 80 kVp is irradiated from the back side of each sample (surface on which no phosphor layer is formed) through a lead MTF chart, and the radiation image detection is configured by the scintillator panel and the CMOS flat panel. Detected by the instrument and recorded on the 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.

<Moisture resistance>
According to the above MTF measurement method, 80 kV X-rays were irradiated from the back surface of each sample, and the initial MTF was measured. Each sample was stored at 65 ° C., 85% for 3 days, and after the storage, the same image was taken, and the initial MTF was compared. If the MTF after storage is larger than the initial 80%, it can be used. A value of 1 cycle / mm was used for the calculation of the MTF ratio.

  From the above, it can be seen that according to the present invention, a scintillator panel that simplifies the production process and has excellent moisture resistance can be obtained.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of scintillator panel 2 Vacuum container 3 Vacuum pump 4 Support body 5 Support body holder 6 Support body rotating mechanism 7 Support body rotating shaft 8 Evaporation source 9 Shutter 10 Scintillator panel 11 Moisture-resistant protective film 12 Phosphor layer 13 Undercoat layer 14 Metal Reflective Layer 15 Support 16 Metal Thin Film Layer

Claims (10)

A scintillator panel having a phosphor layer that converts the radiation into light to the support is obtained by cutting the support Gallo Lumpur shaped scintillator panel support in a predetermined size, of the support A metal thin film layer having a thickness in the range of 1 to 500 nm is provided on the surface opposite to the surface having the phosphor layer, and the light emitting surface and side surface of the phosphor layer and the side surface of the support are moisture resistant. Covered with a protective film ,
A scintillator panel, wherein the phosphor used in the phosphor layer is a columnar crystal phosphor formed by a vapor deposition method . The scintillator panel according to claim 1 , wherein the support is made of a flexible polymer film. The scintillator panel according to claim 1 or 2, wherein the moisture-resistant protective film is an organic film formed by a vapor deposition method. Moisture permeability of the metal thin film layer is 90% under a temperature 40 ° C. · relative humidity, the scintillator according to any one of claims 1 to 3, characterized in that not more than 50g / m2 · 24h panel. The metal thin film layer is at least aluminum (Al) or silver (Ag) of which contains one or aluminum claim 1, characterized in that it contains an alloy containing alloy or silver containing up to claim 4 The scintillator panel according to any one of the above. The scintillator panel according to any one of claims 1 to 5, characterized in that it comprises a subbing layer made of a polymer material on the metal thin film layer. The phosphor layer, a scintillator panel according to any one of the cesium iodide, from claim 1, characterized in that the additive comprising thallium formed as raw materials to claim 6. A method of manufacturing a scintillator panel in which a phosphor layer for converting radiation into light is provided on a support, the support being supplied in a roll-to-roll manner, and the surface of the support having the phosphor layer the metal thin film layer has a continuously formed to process, and have a step of coating a light emitting surface and the side surfaces and the support side surface of the phosphor layer with moisture-resistant protective film on the opposite side of,
A method of manufacturing a scintillator panel, wherein the phosphor using the phosphor layer is a columnar crystal phosphor formed by a vapor deposition method. 9. The method of manufacturing a scintillator panel according to claim 8 , further comprising the step of simultaneously forming the metal thin film layer and the metal reflective layer. Radiographic image detector characterized by using the scintillator panel according to any one of claims 1 to 7.