JP2019109171A - Scintillator panel and radiation image detection device - Google Patents

Abstract

To provide a scintillator panel capable of suppressing film peeling of a phosphor layer of the scintillator panel and occurrence of scraped waste of the phosphor even in the case where a content of binder resin is small.SOLUTION: A scintillator panel has a phosphor layer containing a phosphor and binder resin on a substrate, and the content of the binder resin in relation to the content of 100 pts.vol. of the phosphor in the phosphor layer is 18 pts.vol. or less. The scintillator panel has a coating layer on an outer peripheral side face of the phosphor layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a scintillator panel, a scintillator panel with a release sheet using the same, and a radiation image detecting apparatus.

  In the past, radiographic images using films have been widely used in medical settings. However, since radiographic images using films are analog image information, digital radiographic images such as computed radiography (CR) and flat panel detectors (FPD) have recently been used. Detection devices have been developed. There are direct and indirect methods in this FPD. The direct method is a method of converting radiation directly into an electrical signal for detection. On the other hand, the indirect method is a method in which radiation is once converted to visible light by a scintillator panel, and then the visible light is detected by a photoelectric conversion imaging device. Therefore, the indirect type radiation image detection apparatus is composed of a photoelectric conversion imaging element substrate and two substrates of a scintillator panel. An optically transparent adhesive layer is formed in order to closely contact the photoelectric conversion imaging element substrate and the scintillator panel and to suppress the reduction in resolution due to the diffusion of fluorescent light between the photoelectric conversion imaging element substrate and the scintillator panel, Bonding of a photoelectric conversion imaging element substrate and a scintillator panel is performed.

  In general, a photoelectric conversion imaging element substrate two-dimensionally has 50 to 300 μm pixels including a photodiode, a thin film transistor, an electrical wiring, and the like on a glass substrate. The radiation information is converted into a digital signal by converting visible light generated in the scintillator panel into an electrical signal by a photodiode or the like.

  The scintillator panel includes a phosphor layer containing a phosphor such as gadolinium oxysulfide (GOS) or cesium iodide (CsI), and the phosphor emits visible light in response to the irradiated radiation.

  As the adhesive layer, a film-like pressure-sensitive adhesive sheet called OCA (Optical Clear Adhesive) is generally used. A structure having a bonding layer sandwiched between two release sheets is generally used, and the bonding layer can be formed only by transfer processing without requiring a coating step, so that high-yield bonding can be achieved by a simple method. .

  The scintillator panel can be formed, for example, by applying a phosphor layer containing a phosphor and a binder resin on a sheet-like plastic substrate and then drying it. The adhesive layer can be formed by pressure-bonding the exposed adhesive layer onto the surface of the scintillator panel substrate using a laminator roll or the like after peeling off one release sheet of OCA. Next, the release sheet on the opposite side of the OCA is peeled off, and the exposed adhesive layer is pressure-bonded to the photoelectric conversion imaging element substrate using a laminator roll, thereby bringing the photoelectric conversion imaging element substrate into close contact with the scintillator panel It can be adjusted.

  The higher the content of the phosphor, the higher the luminance of the phosphor layer, and the better the characteristics as an FPD. On the other hand, as the content of the binder resin decreases, the phosphor layer becomes brittle and the strength of the film is reduced. Therefore, film peeling or fluorescence may be caused during manufacture of the scintillator panel or subsequent transportation or bonding to the photoelectric conversion imaging element substrate. There is a tendency for scraping of the body layer to occur easily. In particular, in the outer peripheral portion of the phosphor layer, film peeling due to bending or rubbing or scraping of the phosphor layer is likely to occur. Therefore, in order to cope with such a problem, the thickness of the phosphor layer at the end of the two opposing sides is thinner than the average thickness of the phosphor layer, and the packing density of the phosphor around the end is the fluorescence A radiation image conversion panel (see, for example, Patent Document 1) which is higher than the average filling density of phosphors in a body layer, a radiation conversion sheet (for example, having an edge sticking member provided on the side of the periphery of the phosphor layer) 2), a radiation image conversion panel (see, for example, Patent Document 3) or the like in which a coating layer including at least one metal-containing metal-containing layer is formed on the non-laminated surface side of the phosphor layer Proposed.

JP-A-61-228399 Unexamined-Japanese-Patent No. 2010-101722 Japanese Patent Application Publication No. 2007-85797

  When an OCA having a release sheet is used in the step of attaching the scintillator panel to the photoelectric conversion imaging element substrate, only the release sheet formed on the scintillator panel needs to be peeled off, as described in Patent Document 1 In the case of using the OCA having a release sheet, the technique described in (1) has a problem that film peeling of the phosphor layer occurs at the time of peeling of the release sheet. In particular, as the phosphor content in the phosphor layer is high and the binder resin content is low, the phosphor layer becomes brittle and the adhesion with the substrate is also reduced, so that film peeling and scraps of the phosphor layer are generated. It's easy to do. Although the generation of phosphor scraps from the outer peripheral portion of the phosphor can be suppressed by the techniques of Patent Documents 2 and 3, the phosphor layer is increased when the phosphor content is increased and the binder resin content is reduced to improve FPD characteristics. The inventors of the present invention have found that there is a problem that the film peeling is likely to occur.

  Therefore, an object of the present invention is to provide a scintillator panel capable of suppressing the film peeling of the phosphor layer of the scintillator panel and the generation of phosphor scraps even when the binder resin content is small.

  The above object is a scintillator panel having a phosphor layer containing a phosphor and a binder resin on a substrate, wherein the content of the binder resin is 18 volumes relative to 100 parts by volume of the phosphor content in the phosphor layer. This is achieved by a scintillator panel having a covering layer on the outer peripheral side surface of the phosphor layer.

  According to the present invention, the film peeling of the phosphor layer of the scintillator panel and the generation of phosphor scraps can be suppressed.

It is sectional drawing which represented typically the one aspect | mode of the scintillator panel of this invention. It is sectional drawing which represented typically the edge part of the one aspect | mode of the scintillator panel of this invention. It is sectional drawing which represented typically the one aspect | mode of the radiographic image detection apparatus of this invention.

  The scintillator panel of the present invention has a phosphor layer on a substrate and has a covering layer on the outer peripheral side of the phosphor layer. The substrate has the function of supporting the phosphor layer. The phosphor layer has the function of converting the irradiated radiation into light of a longer wavelength. The light to be converted is preferably visible light. The scintillator panel of the present invention is characterized by having a covering layer on the side surface of the peripheral portion of the phosphor layer. By providing the covering layer on the side surface of the phosphor layer, it is possible to suppress the generation of phosphor scraps in the outer peripheral portion of the phosphor layer. In addition, even when the binder resin content in which the film peeling of the phosphor layer is likely to occur is small, the adhesion between the phosphor layer and the substrate can be improved to suppress the film peeling of the phosphor layer.

  FIG. 1 is a cross-sectional view schematically showing a scintillator panel of the present invention. The scintillator panel 2 has a phosphor layer 5 on a substrate 4 and a covering layer 8 on the outer peripheral side of the phosphor layer 5. Here, the side surface of the outer peripheral portion of the phosphor layer refers to an end portion of the phosphor layer in the direction substantially perpendicular to the substrate surface. An adhesive layer 7 may be provided on the phosphor layer 5 as necessary. By providing the adhesive layer 7, the adhesion between the scintillator panel and the photoelectric conversion imaging element substrate can be further improved, the diffusion of fluorescent light can be suppressed, and the image sharpness can be improved. In this case, it is preferable to have the release sheet 6 on the adhesive layer 7 from the viewpoint of handleability.

  As a material which comprises a board | substrate, glass which has radiation permeability, a ceramic, a semiconductor, a high molecular compound, a metal, a metal oxide etc. are mentioned, for example. Examples of the glass include quartz, borosilicate glass, and chemically strengthened glass. Examples of the ceramic include sapphire, silicon nitride, silicon carbide and the like. Examples of the semiconductor include silicon, germanium, gallium arsenide, gallium phosphorus, gallium nitrogen and the like. Examples of the polymer compound include cellulose acetate, polyester, polyamide, polyimide, triacetate, polycarbonate, carbon fiber reinforced resin and the like. As a metal, aluminum, iron, copper etc. are mentioned, for example. As a metal oxide, a titanium oxide etc. are mentioned, for example. Two or more of these may be used. Among these, glass and a polymer compound are preferable, and white polyester containing a void is more preferable, because the visible light transmittance is high and the light emitted from the phosphor can be efficiently used.

  In light of weight reduction of the scintillator panel, the thickness of the substrate is preferably 2.0 mm or less, and more preferably 1.0 mm or less.

  The phosphor layer contains at least a phosphor and a binder resin. The phosphor has the effect of converting the emitted radiation into longer wavelength light. The binder resin has an effect of enhancing the binding strength between the phosphors and maintaining the shape of the phosphor layer.

The phosphor, _{e.g., CsI, CsBr, Gd 2 O} 2 S ( hereinafter, _{"GOS"), Gd 2 SiO 5, BiGe} 3 O 12, CaWO 4, Lu 2 O 2 S, Y 2 O 2 S, LaCl _{3, LaBr 3, LaI 3,} CeBr 3, CeI 3, etc. LuSiO ₅ and the like. Two or more of these may be contained. Among these, GOS and CsI are preferable.

  An activator may be added to the phosphor, and the light emission efficiency can be improved. As an activator, for example, sodium (Na), indium (In), thallium (Tl), lithium (Li), potassium (K), rubidium (Rb), sodium (Na), terubinium (Tb), cerium (Ce) And europium (Eu), praseodymium (Pr) and the like. Two or more of these may be contained. From the viewpoints of high chemical stability and high light emission efficiency, sulfated gadolinium (GOS: Tb) to which terbinium is added, and cesium iodide (CsI: Tl) to which thallium is added are preferable.

  The shape of the phosphor is preferably spherical, flat, rod-like or the like. The particle size (D50) of the phosphor is preferably 1.0 to 20 μm. Here, the particle size (D50) of the fluorescent substance is determined by introducing the fluorescent substance into a water-filled sample chamber using a particle size distribution measuring apparatus (for example, MT3300; manufactured by Nikkiso Co., Ltd.) and sonicating for 300 seconds It can calculate from the particle size distribution measured after performing.

  Examples of the binder resin include polyvinyl butyral, polyvinyl acetate, polyvinyl alcohol, ethyl cellulose, methyl cellulose, polyethylene, silicone resins such as polymethyl siloxane and polymethyl phenyl siloxane, polystyrene, butadiene / styrene copolymer, polystyrene, polyvinyl pyrrolidone, polyamide And high molecular weight polyethers, ethylene oxide / propylene oxide copolymers, polyacrylamides, acrylic resins and the like. Two or more of these may be contained. It is preferable to select according to the material which forms the coating layer mentioned later, Among these, a viewpoint of compatibility with a coating layer to polyvinyl butyral, polyvinyl alcohol, an ethyl cellulose, and methylcellulose are preferable.

  The content of the binder resin relative to 100 parts by volume of the phosphor in the phosphor layer is 18 parts by volume or less. When the content of the binder resin is 18 parts by volume or less in order to improve FPD characteristics, in the prior art, there has been a problem that film peeling of the phosphor layer and scraps of phosphor are easily generated. These problems can be solved by providing the covering layer. In addition, since the content of the phosphor can be relatively increased, the luminance can be further improved. On the other hand, the content of the binder resin is preferably 5 parts by volume or more from the viewpoint of strengthening the bonding between the phosphors and further suppressing the film peeling.

  It may have two or more phosphor layers. It is preferable to have a plurality of phosphor layers in which the particle diameter (D50) of the phosphors is different, and the image sharpness can be improved. In this case, the layer having a small particle diameter (D50) of the phosphor and the highest packing density, that is, the high packing density phosphor layer, has high reflectance of visible light, so diffusion of fluorescent light is suppressed and image sharpness is reduced. It is preferable to be located on the radiation incident side because it can be improved. On the other hand, it is preferable that the layer having a larger particle size of the phosphor than the high density phosphor layer be located on the light receiving surface side of the photoelectric conversion imaging device substrate in order to improve the photoelectric conversion efficiency because the emitted light is large. .

  The thickness of the phosphor layer is preferably 10 μm or more, more preferably 80 μm or more, from the viewpoint of improving the light emission efficiency. On the other hand, the thickness of the phosphor layer is preferably 600 μm or less, more preferably 250 μm or less, from the viewpoint of improving the image sharpness.

  As a material which forms a coating layer, polyvinyl alcohol, polyester, a polyurethane, an acrylic resin, a silicone resin, a fluorine resin, these copolymers etc. are mentioned, for example. Two or more of these may be contained. Among these, polyvinyl alcohol is preferable, and the adhesion between the peripheral portion of the phosphor layer and the substrate can be improved, and film peeling of the phosphor layer can be further suppressed. In addition, since polyvinyl alcohol is easy to form a thin film, it is difficult for burrs to be generated, and when the scintillator panel is bonded to the photoelectric conversion imaging element substrate, it is possible to suppress air bubble mixing due to the burrs.

  The scintillator panel of the present invention may have a protective film on the phosphor layer. A transparent organic polymer film etc. are mentioned as a protective film.

  In FIG. 2, sectional drawing which represented typically the edge part of the one aspect | mode of the scintillator panel of this invention is shown. The porosity of the end 12 of the phosphor layer is preferably lower than that of the inside 13 of the phosphor layer, and the adhesion between the phosphor layer and the substrate is improved in the peripheral portion of the phosphor layer which is easily peeled off. Thus, the film peeling of the phosphor layer can be further suppressed. The porosity of the end 12 of the phosphor layer is more preferably less than 10%. In addition, when forming a coating layer using the coating liquid mentioned later, the porosity tends to fall on the outer peripheral side of a fluorescent substance layer by penetration of a coating liquid, and the adhesiveness of a fluorescent substance layer and a base material is made more It can be improved. Here, the end 12 of the phosphor layer indicates a region up to 100 μm from the side surface of the phosphor layer to the inside, and the inside 13 of the phosphor layer is all the inside except the end of the phosphor layer It points to the area. In addition, the porosity of the phosphor layer can be obtained by precisely observing the cross section of the phosphor layer and then magnifying and observing it at a magnification of 2000 times using a scanning electron microscope (for example, S2400; manufactured by Hitachi, Ltd.) The solid content portion (phosphor, binder resin, etc.) and the void portion in the image can be image-converted into two gradations, and it can be calculated from the area ratio of the void portion to the area of the cross section of the phosphor layer.

  In the scintillator panel of the present invention, the angle between the surface of the covering layer and the surface of the substrate in contact with the phosphor layer is preferably more than 90 °. When the angle exceeds 90 °, the release sheet is likely to be peeled off when used as a release sheet-attached scintillator panel. Here, the surface of the covering layer means the outermost surface in the layer surface direction of the covering layer extending in a direction substantially perpendicular to the substrate surface at the outer peripheral portion of the phosphor layer. The angle between the surface of the covering layer and the surface of the substrate in contact with the phosphor layer is determined by precision polishing the cross section of the end of the phosphor layer, and then using an optical microscope (for example, VHX-900F; Keyence Corporation) It can be magnified and observed at a magnification of 100 times and can be measured using an angle measurement function. As a method of making this angle 90 degrees or more, for example, in the manufacture of a scintillator panel, a method of cutting by a preferable method described later, etc. may be mentioned.

  The scintillator sheet with release sheet of the present invention has an adhesive layer and a release sheet in this order on the phosphor layer of the scintillator panel.

  The material constituting the adhesive layer is preferably an optically transparent thermosetting resin or a photocurable resin from the viewpoint of strength and workability. Specifically, transparent adhesives, such as an acrylic resin, an epoxy resin, a polyester resin, a butyral resin, a polyamide resin, a silicone resin, and an ethyl cellulose resin, are mentioned, for example. The adhesive layer may optionally contain additives such as a crosslinking agent, a plasticizer, a tackifier, a filler, and an antidegradant. The thickness of the adhesive layer is preferably 10 to 50 μm.

  As a release sheet, resin films, such as a polyethylene terephthalate, a polycarbonate, a polyacrylate, a polypropylene, are mentioned, for example. A release coat layer (silicone layer) may be provided on the bonding surface of the release sheet to the adhesive layer. The thickness of the release sheet is more preferably 10 to 75 μm.

  In the scintillator panel of the present invention, for example, a phosphor paste containing at least a phosphor and a binder resin is coated and dried on a substrate to form a phosphor layer, and a coating liquid is applied to the side surface of the peripheral portion of the phosphor layer -It can obtain by drying and forming a coating layer. In the case of forming an adhesive layer and a release sheet on a phosphor layer, from the viewpoint of workability and economy, a film called OCA (Optical Clear Adhesive Film) in which an adhesive layer is sandwiched between two release sheets. It is preferable to use an adhesive sheet of An adhesive layer and a release sheet are laminated on the phosphor layer by peeling off one release sheet of OCA and bonding the adhesive layer on the phosphor layer side to make a scintillator panel with a release sheet. Can.

  The phosphor paste contains at least the above-mentioned phosphor and a binder resin. You may contain additives and organic solvents, such as a thickener, a plasticizer, and an antisettling agent, as needed. The organic solvent is a good solvent for the binder resin, and preferably has a large hydrogen bonding ability. Benzyl alcohol, tetrahydrofuran, dimethyl sulfoxide, dihydroterpineol, γ-butyrolactone, dihydroterpinyl acetate, 3-methoxy-3-methyl-methylbutanol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, N, N-dimethyl Formamide, hexylene glycol, bromobenzoic acid, etc. It is below. Two or more of these may be contained.

  Examples of the method for applying the phosphor paste include a method using a screen printing method, a bar coater, a roll coater, a die coater, a blade coater, and the like.

  In the production of the release sheet-attached scintillator panel, a method is preferable in which a scintillator panel of a large size and a release sheet are pasted together and then cut into a predetermined size. It is preferable to use a press cutter (Tomson Cut) to insert a blade from the substrate surface of the scintillator panel toward the release sheet surface, and the outer peripheral side surface of the phosphor layer and the substrate surface on the side in contact with the phosphor layer The angle between them can easily be made larger than 90 °.

  Next, a radiation image detection apparatus of the present invention will be described. The radiation image detection apparatus of the present invention has at least the aforementioned scintillator panel, adhesive layer, and photoelectric conversion imaging device substrate.

  FIG. 3 is a cross-sectional view schematically showing one aspect of the radiation detection apparatus of the present invention. The radiation image detection apparatus 1 is formed by bonding the scintillator panel 2 and the photoelectric conversion imaging element substrate 3 via the adhesive layer 7 and further includes a power supply unit (not shown). The photoelectric conversion imaging element substrate 3 has the photoelectric conversion layer 9 and the output layer 10 on the substrate 11. However, for convenience of illustration, the downward direction in the paper surface of FIG. 3 is the upward direction in the present description. The photoelectric conversion layer 9 generally has a two-dimensional pixel formed with a photoelectric conversion element (not shown) and a TFT. It is preferable that the light emitting surface of the scintillator panel 2 and the photoelectric conversion layer 9 of the photoelectric conversion imaging element substrate 3 be adhered or adhered via the adhesive layer 7.

  The radiation that has entered the radiation image detection device 1 is absorbed by the phosphor in the phosphor layer 5, and visible light is emitted. When the emitted visible light reaches the photoelectric conversion layer 9, it is photoelectrically converted by the photoelectric conversion layer 9 and output as an electrical signal through the output layer 10.

  Hereinafter, the present invention will be more specifically described by way of examples and comparative examples, but the present invention is not limited thereto. First, the evaluation method will be described.

<Void ratio of phosphor layer>
After precisely polishing the cross section of the phosphor layer formed in each Example and Comparative Example, the phosphor layer was observed at a magnification of 500 using a scanning electron microscope (S2400; manufactured by Hitachi, Ltd.). In the obtained image, the solid portion (phosphor, binder resin, etc.) and the void portion are image converted into two gradations by image processing software (Adobe Photoshop; made by Adobe Systems Co., Ltd.), and the area of the cross section of the scintillator layer The area ratio of the void portion occupying in was calculated as the porosity. The porosity of the end portion of the phosphor layer was calculated by the method described above in the range of 100 μm from the side of the phosphor layer toward the inside. The porosity of the inside of the phosphor layer was calculated by the method described above in the range exceeding 100 μm from the side of the phosphor layer toward the inside.

<Angle between the surface of the covering layer and the surface of the substrate in contact with the phosphor layer>
After precision polishing of the end section of the release sheet-attached scintillator panel obtained in each of the examples and comparative examples, the magnified view is observed at a magnification of 100 times using an optical microscope (VHX-900F; manufactured by Keyence Corporation), An angle measurement function was used to measure the angle between the surface of the coating layer and the surface of the substrate in contact with the phosphor layer.

<Air bubbles caused by the covering layer>
After the white PET film substrate surface of the release sheet-attached scintillator panel obtained by each of the examples and the comparative example is adsorbed to an adsorption stage, the release sheet is peeled off, and photoelectric conversion imaging of the scintillator panel is performed via the adhesive layer. It was bonded to the element substrate to produce a radiation image detection apparatus. However, in Example 7, the scintillator panel and the photoelectric conversion imaging element substrate were attached to each other with a polyester tape (559 A; manufactured by Nichiban Co., Ltd.) to produce a radiation image detection apparatus. The obtained radiation image detection apparatus was irradiated with X-ray of a tube voltage of 60 kVp from the substrate side of the scintillator panel, light emission from the scintillator layer was detected by FPD, and a light emission image was acquired. The obtained luminescence image was visually observed, and the inclusion of air bubbles caused by the covering layer on the outer peripheral portion of the scintillator panel was determined according to the following criteria.
○: no bubble inclusion due to the covering layer is confirmed x: bubble inclusion due to the covering layer is confirmed.

<Peeling off of phosphor layer>
Scintillator panels with release sheet obtained by each example and comparative example After each 50 white PET film substrate surfaces of the release sheet are adsorbed to the adsorption stage, the release sheet is peeled off, and the phosphor layer is visually observed. The presence or absence of peeling was determined based on the following criteria. However, in Example 7, since the release sheet was not provided, the formed phosphor layer was visually observed as it was.
:: Less than four locations where film peeling of the phosphor layer is observed in 200 square corner portions ○: four or more locations where film peeling of the phosphor layer is observed in 200 square corners Less than 10 locations x: 10 or more locations where film peeling of the phosphor layer is observed in 200 square corners.

<Shavings of phosphor layer>
After the white PET film substrate surface of the scintillator sheet with a release sheet obtained by each of the examples and comparative examples is adsorbed to the adsorption stage, the release sheet is peeled off, the release sheet is peeled off, and the adhesive layer is interposed. The scintillator panel was then bonded to the photoelectric conversion imaging device substrate to fabricate a radiation image detection apparatus. However, in Example 7, the scintillator panel and the photoelectric conversion imaging element substrate were attached to each other with a polyester tape (559 A; manufactured by Nichiban Co., Ltd.) to produce a radiation image detection apparatus. The obtained radiation image detection apparatus was irradiated with X-ray of a tube voltage of 60 kVp from the substrate side of the scintillator panel, light emission from the scintillator layer was detected by FPD, and a light emission image was acquired. The obtained luminescence image was visually observed, and the contamination caused by scraping of the phosphor layer was determined according to the following criteria.
Good: Foreign matter attributable to shavings of the phosphor layer is not confirmed. X: Foreign matter attributable to shavings of the phosphor layer is mixed between the scintillator panel and the photoelectric conversion imaging element substrate.

<Relative brightness and relative image sharpness>
The release sheet-attached scintillator panel obtained in each of the examples and comparative examples was peeled off from the release sheet and set in an FPD (PaxScan 3030; manufactured by Varian) to prepare a radiation image detection apparatus. However, in Example 7, the scintillator panel and the photoelectric conversion imaging element substrate were attached to each other with a polyester tape (559 A; manufactured by Nichiban Co., Ltd.) to produce a radiation image detection apparatus. The radiation image detection apparatus was irradiated with X-ray of a tube voltage of 60 kVp from the substrate side of the scintillator panel, the amount of light emission from the scintillator layer was detected by FPD, and the luminance of the scintillator panel was evaluated. Also, the image sharpness of the scintillator panel was evaluated based on the captured image of the rectangular wave chart. The relative brightness and the relative image sharpness were calculated when the brightness and the image sharpness of the scintillator panel described in Example 1 were 100. When the relative luminance and the relative image sharpness are both less than 90, the characteristics as an FPD are insufficient. The calculated relative luminance and relative image sharpness were determined according to the following criteria.
◎: 100 or more ○: 90 or more and less than 100 ×: less than 90.

(Preparation of phosphor paste 1)
20 parts by mass of an organic binder (ethyl cellulose (7 mPa · s); specific gravity 1.1 g / cm ³ ) is dissolved by heating in 80 parts by mass of an organic solvent (terpineol, specific gravity 0.93 g / cm ³ ) at 80 ° C. A solution was obtained. In addition, Tb-activated Gd ₂ O ₂ S (GOS: Tb, specific gravity 7.3 g / cm ³ ) having an average particle diameter D50 of 10 μm was prepared as the phosphor powder 1. A phosphor paste 1 was prepared by mixing 93.0 parts by mass of the phosphor powder with 7.0 parts by mass of the organic solution.

(Preparation of phosphor paste 2)
A phosphor paste 2 was produced in the same manner as the production of the phosphor paste 1 except that 96.4 parts by weight of the phosphor powder was mixed with 3.6 parts by weight of the organic solution.

(Preparation of phosphor paste 3)
A phosphor paste 3 was produced in the same manner as the production of the phosphor paste 1 except that 88.1 parts by weight of the phosphor powder was mixed with 11.9 parts by weight of the organic solution.

(Preparation of phosphor paste 4)
A phosphor paste 4 was produced in the same manner as the production of the phosphor paste 1 except that 86.9 parts by weight of the phosphor powder was mixed with 13.1 parts by weight of the organic solution.

(Preparation of phosphor paste 5)
An organic solution was obtained by the same method as that of the phosphor paste 1. Further, the phosphor powder 2, the average particle size D50 5μm of Tb-activated _{Gd 2 O 2 S (Gd 2} O 2 S: Tb, a specific gravity of 6.9 g / cm ³⁾ was prepared. 92.6 parts by mass of the phosphor powder 2 was mixed with 7.4 parts by mass of the organic solution to prepare a phosphor paste 5.

(Preparation of phosphor paste 6)
A phosphor paste 6 was produced in the same manner as the production of the phosphor paste 5 except that 96.2 parts by weight of the phosphor powder was mixed with 3.8 parts by weight of the organic solution.

(Preparation of phosphor paste 7)
A phosphor paste 7 was produced in the same manner as the production of the phosphor paste 5 except that 87.5 parts by weight of the phosphor powder was mixed with 12.5 parts by weight of the organic solution.

(Preparation of Coating Solution 1)
A coating solution 1 is prepared by dissolving 50 parts by mass of polyvinyl alcohol (E-AL-200; manufactured by Arabic Yamato Co., Ltd.) in 50 parts by mass of ethanol (055-00457; manufactured by Wako Pure Chemical Industries, Ltd.) did.

Example 1
Using a die coater, apply the above-mentioned phosphor paste 1 on a 200 mm × 200 mm white PET film substrate (E6SQ; Toray Industries, Inc.) so that the thickness of the phosphor layer after drying becomes 200 μm, 80 The first phosphor layer was formed by drying in a hot air drying oven for 4 hours. The content of the binder resin relative to 100 parts by volume of the phosphor in the first phosphor layer was 10 parts by volume.

  An OCA film (8171-CL; manufactured by 3M Japan Co., Ltd.) in which a release film having a thickness of 50 μm was laminated on both sides of a 25 μm-thick adhesive layer was prepared. After peeling off one release sheet of the OCA film, using a bonding apparatus (HAL-650S; made by Sankyo Co., Ltd.), it is pasted so that the exposed adhesive layer is in contact with the first phosphor layer Then, the adhesive layer and the other release sheet were laminated on the first phosphor layer.

  The coating solution 1 is applied to the entire periphery of the first phosphor layer end side surface and dried to form a coating layer on the outer peripheral portion side surface of the first phosphor layer, and a scintillator panel with a release sheet is obtained. Made.

  Then, using a press cutter (MP-600SL; manufactured by Sakai Machine Industry Co., Ltd.) and a Thomson blade with a blade angle of 30 °, insert the blade from the substrate surface of the scintillator panel toward the release sheet surface, 100 mm It was cut into a square of 100 mm. It was 105 degrees when the angle of the coating layer surface and the board | substrate surface of the side which contact | connects a fluorescent substance layer to make was measured by the above-mentioned method.

  The results of evaluation of the obtained release sheet-attached scintillator panel are shown in Table 1. When the porosity of the phosphor layer was measured by the above-mentioned method, the inside of the phosphor layer was 15%, and the end of the phosphor layer was 5%. The film peeling of the phosphor layer of the scintillator panel was good at less than 4 out of 200 square corner portions. The generation of chips and the inclusion of air bubbles due to the coating layer were not observed, and the adhesion to the photoelectric conversion imaging device substrate was good. The luminance and image sharpness of the scintillator panel were also good.

(Example 2)
A scintillator sheet with a release sheet was obtained by the same method as in Example 1 except that the phosphor paste 2 was used instead of the phosphor paste 1. The content of the binder resin relative to 100 parts by volume of the phosphor in the first phosphor layer was 5 parts by volume. The results evaluated in the same manner as Example 1 are shown in Table 1. The film peeling of the phosphor layer of the scintillator panel was good at less than 4 out of 200 square corner portions. The generation of chips and the inclusion of air bubbles due to the coating layer were not observed, and the adhesion to the photoelectric conversion imaging device substrate was good. The relative luminance was 105, which was good. The relative image sharpness was 94, was over 90, and satisfied the characteristics as an FPD.

(Example 3)
A scintillator sheet with a release sheet was obtained by the same method as in Example 1 except that the phosphor paste 3 was used instead of the phosphor paste 1. The content of the binder resin relative to 100 parts by volume of the phosphor in the first phosphor layer was 18 parts by volume. The results evaluated in the same manner as Example 1 are shown in Table 1. The film peeling of the phosphor layer of the scintillator panel was good at less than 4 out of 200 square corner portions. The generation of chips and the inclusion of air bubbles due to the coating layer were not observed, and the adhesion to the photoelectric conversion imaging device substrate was good. The relative luminance was 93, was over 90, and satisfied the characteristics as an FPD. The relative image sharpness was 107, which was good.

(Example 4)
The phosphor paste 5 was applied onto a 200 mm × 200 mm white PET film substrate using a die coater such that the thickness of the phosphor layer after drying was 40 μm. The phosphor paste 1 was applied thereon using a die coater such that the thickness of the phosphor layer after drying was 180 μm. And it dried in 80 degreeC hot-air-drying furnace for 4 hours, and formed the 1st fluorescent substance layer and the 2nd fluorescent substance layer. The total content of the binder resin relative to 100 parts by volume of the total content of the phosphors in the first phosphor layer and the second phosphor layer was 10 parts by volume. After that, a scintillator sheet with a release sheet was obtained by the same method as in Example 1. The results evaluated in the same manner as Example 1 are shown in Table 1. The film peeling of the phosphor layer of the scintillator panel was good at less than 4 out of 200 square corner portions. The generation of chips and the inclusion of air bubbles due to the coating layer were not observed, and the adhesion to the photoelectric conversion imaging device substrate was good. The relative luminance was 95, was over 90, and satisfied the characteristics as an FPD. The relative image sharpness was 115, which was good.

(Example 5)
A scintillator sheet with a release sheet was obtained by the same method as in Example 4 except that instead of the phosphor paste 5, the phosphor paste 6 was replaced with the paste 1 and the phosphor paste 2 was used. The content of the binder resin relative to 100 parts by volume of the phosphor in the first phosphor layer was 5 parts by volume. The results evaluated in the same manner as Example 1 are shown in Table 1. The film peeling of the phosphor layer of the scintillator panel was good at less than 4 out of 200 square corner portions. The generation of chips and the inclusion of air bubbles due to the coating layer were not observed, and the adhesion to the photoelectric conversion imaging device substrate was good. The relative luminance was 106 and the relative image sharpness was 104, which was good.

(Example 6)
A scintillator sheet with a release sheet was obtained by the same method as in Example 4 except that instead of the phosphor paste 5, the phosphor paste 7 was replaced with the paste 1 and the phosphor paste 3 was used. The content of the binder resin relative to 100 parts by volume of the phosphor in the first phosphor layer was 18 parts by volume. The results evaluated in the same manner as Example 1 are shown in Table 1. The film peeling of the phosphor layer of the scintillator panel was good at less than 4 out of 200 square corner portions. The generation of chips and the inclusion of air bubbles due to the coating layer were not observed, and the adhesion to the photoelectric conversion imaging device substrate was good. The relative luminance was 96, was over 90, and satisfied the characteristics as an FPD. The relative image sharpness was 117, which was good.

(Example 7)
A scintillator panel was obtained by the same method as in Example 1 except that the adhesive layer and the release sheet were not laminated. The results evaluated in the same manner as Example 1 are shown in Table 1. The film peeling of the phosphor layer of the scintillator panel was good at less than 4 out of 200 square corner portions. The generation of chips and the inclusion of air bubbles due to the coating layer were not observed, and the adhesion to the photoelectric conversion imaging device substrate was good. The relative luminance was 100, which was good. The relative image sharpness was 97, was over 90, and satisfied the characteristics as an FPD.

(Example 8)
A scintillator panel with a release sheet was obtained by the same method as in Example 1 except that a silicone resin (KE-45; manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of the coating solution 1 described above. The results evaluated in the same manner as Example 1 are shown in Table 1. The film peeling of the phosphor layer of the scintillator panel was good at four or more and less than ten in 200 square corners. Although generation of shavings was not recognized, air bubble mixing caused by the coating layer occurred. The relative luminance and the relative image sharpness were as good as 100.

(Comparative example 1)
A scintillator panel was obtained by the same method as in Example 1 except that the covering layer was not formed. The results evaluated in the same manner as Example 1 are shown in Table 1. Peeling of the phosphor layer of the scintillator panel was not less than 10 out of 200 at the corner portions of the square. Scrapings were generated, and the adhesion to the photoelectric conversion imaging device substrate was poor. The relative luminance and the relative image sharpness were as good as 100.

(Reference example)
Example except using the phosphor paste 4 in place of the phosphor paste 1 and inserting the edge of the release sheet from the release sheet surface toward the substrate surface of the scintillator panel instead of using a Thomson blade having a blade angle of 30 ° A scintillator sheet with a release sheet was obtained in the same manner as in 1. The results evaluated in the same manner as Example 1 are shown in Table 1. The thickness of the phosphor layer was thinner at the inside of the phosphor layer than at the end of the phosphor layer, and the porosity of the phosphor layer was 11% at the inside of the phosphor layer and 2% at the end of the phosphor layer. The film peeling of the phosphor layer of the scintillator panel was good at less than 4 out of 200 square corner portions. The generation of chips and the inclusion of air bubbles caused by the coating layer were not observed, and the adhesion to the photoelectric conversion imaging device substrate was good. The relative luminance was 88, which was below 90, which was not good. The relative image sharpness was 109, which was good.

DESCRIPTION OF SYMBOLS 1 radiation image detection apparatus 2 scintillator panel 3 photoelectric conversion imaging element substrate 4 substrate 5 fluorescent substance layer 6 release sheet 7 adhesive layer 8 covering layer 9 photoelectric conversion layer 10 output layer 11 substrate 12 end part 13 fluorescent substance layer Inside 14 cladding layer surface

Claims (8)

A scintillator panel having a phosphor layer containing a phosphor and a binder resin on a substrate, wherein the content of the binder resin is 18 parts by volume or less with respect to 100 parts by volume of the phosphor in the phosphor layer, The scintillator panel which has a coating layer in the outer peripheral part side surface of the said fluorescent substance layer. The scintillator panel according to claim 1, wherein the phosphor layer comprises a plurality of layers having different particle sizes of phosphors. The scintillator panel according to any one of claims 1 to 2, wherein the porosity of the end portion of the phosphor layer is lower than the porosity of the inside. The scintillator panel according to any one of claims 1 to 3, wherein the porosity of the end portion of the phosphor layer is less than 10%. The scintillator panel according to any one of claims 1 to 4, wherein the angle formed by the surface of the covering layer and the substrate surface on the side in contact with the phosphor layer exceeds 90 degrees. The scintillator panel according to any one of claims 1 to 5, wherein the covering layer comprises polyvinyl alcohol. The scintillator panel with a release sheet which has an adhesive layer and a release sheet in this order on the fluorescent substance layer of the scintillator panel as described in any one of Claims 1-6. The radiation image detection apparatus which has a scintillator panel as described in any one of Claims 1-6, an adhesive layer, and a photoelectric conversion imaging element board | substrate.

Images