JP6519195B2 - Scintillator panel and radiation detector - Google Patents

Description

  The present invention relates to a scintillator panel used for detecting radiation and a radiation detector using the same.

BACKGROUND In recent years, a radiation detector that converts radiation transmitted from a radiation source through an imaging site of a subject into charge and generates a digital radiation image has been used for diagnosis of a medical condition in a medical field. These radiation detectors convert scintillators into visible light with a phosphor layer such as Gd ₂ O ₂ S or CsI, and then convert them into charges with a photoelectric conversion element (PD), and X-rays represented by Se as a representative. It is roughly divided into the method of converting X-rays into electric charge directly by the detection element, and among these, the degree of attention to the scintillator method is high.

  In such a scintillator panel, a scintillator including a phosphor layer is formed on a fiber optics plate (FOP) that transmits light and the FOP. The incidence of radiation produces light in the scintillator and the generated light is propagated in the fiber optics plate.

  Since the phosphor material constituting the scintillator is deliquescent, it is protected from moisture by forming a moisture-proof protective layer made of polyparaxylylene or the like on the top of the scintillator. Since moisture also infiltrates from the interface between the phosphor and the substrate and the adhesive layer that bonds them, the moisture-proof protective layer is formed to cover not only the scintillator surface but also the FOP.

  However, FOP has the disadvantage of poor adhesion to the moisture-proof protective layer. For this reason, it is proposed by Unexamined-Japanese-Patent No. 2005-338067 (patent document 1) to provide an uneven surface in the FOP side wall surface which contacts a moisture-proof protective layer, and to prevent protective layer peeling.

  Further, in Japanese Patent Application Laid-Open No. 2011-257142 (Patent Document 2), the tip of a columnar crystal constituting a scintillator is pasted with a double-sided adhesive film so as to face the FOP to enhance the adhesion between the FOP and the scintillator. It is disclosed.

  In JP 2010-32299 A (patent document 3), a phosphor layer formed on one surface of a substrate and converting radiation into visible light, and the other side of the substrate including the surface of the phosphor layer Disclosed is a moisture-proof layer formed such that the layer thickness covering a part of the other surface of the substrate becomes thinner toward the central part from the peripheral part side of the substrate while covering up to a part of the other surface. It is done.

  However, when providing unevenness on the side surface of the FOP in order to enhance adhesion, the FOP is easily scratched, which causes a problem that the fiber property of the FOP is lowered. In the method proposed above, increasing the thickness of the moistureproof protective layer on the radiation incident side may reduce the optical performance, and the adhesion strength of the moistureproof protective layer on the side of the FOP is not necessarily high. There was a problem that peeling occurred.

JP 2005-338067 JP, 2011-257142, A JP, 2010-322998, A

  The present invention has been made in view of the above-mentioned circumstances, and the change in optical performance due to the moisture proof protective layer on the radiation incident side is small, and the adhesion strength of the moisture proof protective layer on the FOP side is high. It is an object of the present invention to provide a scintillator panel and a radiation detector capable of maintaining high moisture proof performance to the body and achieving both high brightness and high resolution.

The above-mentioned subject according to the present invention is solved by the following means.
That is, the scintillator panel according to the present invention has a radiation incident surface and an emission surface, a fiber optic plate (FOP), and a scintillator for converting radiation provided on the light incident surface on the FOP into visible light; A scintillator panel comprising a moisture-proof protective layer provided on the scintillator and disposed to cover at least a part of the FOP, wherein the moisture-proof protective layer is not disposed on the light emission surface of the FOP. .

  It is preferable that the moistureproof protective layer continuously covers at least a part of the scintillator surface and the entire side surface and the side surface of the FOP. When the distance covered by the moistureproof protective layer on the side surface of the scintillator is A, and the distance covered by the moistureproof protective layer in the thickness direction of the FOP is B, it is preferable to have a relationship of A ≦ B. When the layer thickness of the moisture-proof protective layer on the side of the scintillator is T1, and the layer thickness at the light-emitting side end of the moisture-proof protective layer on the side of the FOP is T2, it is preferable to have a relationship of T1> T2.

  The scintillator comprises a support made of an organic film, an adhesion layer disposed on the radiation emission side on the support, and a phosphor layer having a columnar crystal structure and disposed on the adhesion layer-arranged surface of the support. Is preferred.

  The moisture-proof protective layer is preferably made of paraxylylene polymer. The scintillator and the FOP are preferably in contact with each other via a relief absorption layer, and the relief absorption layer is preferably a layer made of a hot melt resin transparent to visible light. The thickness of the relief layer is preferably 30 μm or less. It is preferable that the uneven absorption layer is a single layer extending over the entire surface in the panel plane direction.

Preferably, the support, the adhesion layer, and the phosphor layer have the same dimensions in the planar direction. The adhesion layer is preferably made of a combination of one or more of a resin, a metal oxide, and a metal. The adhesion layer preferably has a function of absorbing or reflecting the electromagnetic wave generated in the phosphor layer. Moreover, it is preferable that the chamfering process is given to the outer peripheral part of the output surface of FOP at least.
A radiation detector according to the present invention is characterized by using the scintillator panel described above.

In the present invention, the moistureproof protective layer provided on the scintillator and disposed in a form covering at least a part of the FOP is not disposed on the light emission surface of the FOP. As a result, even if the moisture-proof protective layer on the radiation incident side is thickened, the optical performance is not degraded. In addition, since the moisture proof protective layer on the side of the FOP is attached with a sufficient length, the adhesion strength to the side of the FOP is increased, so there is little peeling of the layer.
Therefore, light emitted by radiation irradiation can be propagated to the photoelectric conversion element with high efficiency, and a scintillator panel and a radiation detector with high brightness and high resolution can be provided.

FIG. 1 is a schematic cross-sectional view of a scintillator panel according to the present invention. FIG. 2 is a schematic view showing a configuration of a deposition apparatus for a phosphor used in the present invention. FIG. 3 is a schematic flow diagram showing a method of laminating a phosphor layer and an FOP. FIG. 4 is a schematic flow chart showing a method of forming a moistureproof protective layer. FIG. 5 shows a schematic cross-sectional view of one aspect of the device used to form a protective layer.

Hereinafter, the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
Here, in the present specification, the term "light" is an electromagnetic wave having an electromagnetic wave in a wavelength region ranging from an ultraviolet region to an infrared region centering on visible light, more specifically, having a wavelength from 300 nm to 800 nm. Point to an electromagnetic wave. Further, the term "phosphor" or "scintillator" refers to a phosphor that absorbs the energy of incident radiation such as X-rays to emit the above "light".

Also, the term "transparent", unless stated otherwise, refers to the ability of the "light" to be transmitted without significant reflection and scattering.
Hereinafter, the scintillator panel and the radiation detector according to the present invention, their components, and the modes and modes for carrying out the present invention will be described in detail.

[Scintillator panel]
The basic configuration of the scintillator panel according to the present invention is shown in FIG.
As shown in FIG. 1, the scintillator panel 10 includes a fiber optics plate (FOP) 11, a scintillator layer 12 and a moistureproof protective layer 13 in this order. Here, in the typical aspect of the present invention, radiation is incident on the scintillator panel 10 from the side of the moistureproof protective layer 13 on the top surface of the FOP 11 toward the side of the FOP 11, so that the moisture protection is viewed from the radiation incident side. The protective layer 13, the scintillator layer 12, and the FOP 11 are disposed in this order.

  The moisture-proof protective layer 13 is disposed to cover at least a part of the FOP 11, and the moisture-proof protective layer is not disposed on the light emitting surface of the FOP 11. By adopting such a configuration, it is possible to suppress peeling of the moisture-proof protective layer.

  The moisture-proof protective layer 13 preferably covers at least a part of the side of the FOP continuously along with the entire scintillator surface and side. Therefore, the FOP may be exposed at the emission side lower end of the FOP side surface.

  As shown in FIG. 1, when the distance covered by the moistureproof protective layer on the side surface of the scintillator according to the present invention is A, the thickness of the FOP is C, and the distance covered by the moistureproof protective layer in the thickness direction is B (note that C-B corresponds to the exposed portion, and it is preferable that C.gtoreq.B) and A.ltoreq.B. With this relationship, the contact area of the moisture-proof protective layer to the side of the FOP is sufficiently secured, and peeling is prevented.

  The distance A corresponds to the thickness of the scintillator layer. When the scintillator layer 12 is formed of the support 14, the phosphor 15, and the adhesion layer 16 which is one of the preferable embodiments, the total thickness of these combined corresponds to the distance A.

  When the layer thickness of the moistureproof protective layer on the side surface of the scintillator is T1, and the layer thickness at the light emitting side end of the moistureproof protective layer on the side surface of the FOP is T2, it is preferable to have a relationship of T1> T2. The moisture-proof protective layer has a uniform layer thickness T1 on the side surface of the scintillator, but has a slope toward the end on the output side of the FOP side as shown in FIG. 1 so that the layer thickness becomes T2. The thickness may be reduced stepwise. By adopting such a layer thickness configuration, the adhesion of the moisture-proof protective layer can be further enhanced, and peeling can be suppressed more significantly.

Between the scintillator layer 12 and the FOP 11, as shown in FIG. 1, a relief absorbing layer 17 may be provided. The thickness of the uneven absorption layer is not included in the distances A and B.
Each member constituting the present invention will be described below.

<Fiber Optics Plate (FOP) 11>
A fiber optic plate (FOP) is an optical device formed by bundling several μm optical fibers, and can propagate incident light to a photoelectric conversion element with high efficiency and low distortion. In addition, FOP has a high radiation shielding effect, and can also prevent radiation damage to various elements constituting a photodetector used for a radiation image converter.

FOP can be selected from commercially available ones based on the radiation shielding rate, visible light transmittance and the like. The shape and size of the FOP can be appropriately set according to the application of the scintillator panel 10 and the like, and the shape change such as chamfering can be performed by a conventionally known method. Chamfering the FOP can be expected to have the effect of preventing cracking and damage due to impact at the lower end of the FOP.
Here, the FOP may be chamfered before forming the scintillator layer 12 or after forming the scintillator layer 12 and the moistureproof protective layer 13.

<Scintillator layer 12>
The scintillator layer 12 has a support 14 made of an organic film, an adhesion layer 16 disposed on the radiation emission side on the support, and a phosphor having a columnar crystal structure and disposed on the adhesion layer-arranged surface of the support. And a layer 15.

  It is preferable that the support, the adhesion layer, and the phosphor layer have the same dimensions in the planar direction. With such an identical dimension, an optical characteristic equivalent to that at the center can be obtained at the end, so that the effective area can be maximized.

Support 14
The support refers to a member serving to hold the phosphor layer in the components of the scintillator panel. As the support 14 constituting the scintillator panel of the present invention, a resin film made of an optically transparent polymer material having flexibility is used.

  Here, "having flexibility" means that the elastic modulus (E120) at 120 ° C is 0.1 to 300 GPa. The term "elastic modulus" refers to the slope of the stress relative to the amount of strain indicated by a straight line between the strain indicated by the marked line of the sample in accordance with JIS-C2318 and the corresponding stress using a tensile tester. Is the value obtained. This is a value called Young's modulus, and such Young's modulus is taken as an elastic modulus. The elastic modulus (E120) at 120 ° C. of the support is preferably 0.1 to 300 GPa, and more preferably 1 to 100 GPa.

  Specifically as the resin film having flexibility, as the resin film, polyethylene terephthalate, polyethylene naphthalate, cellulose acetate, polyamide, polyimide, polyetherimide, epoxy, polyamide imide, bismaleimide, fluorine resin, acrylic resin And films made of polyurethane, aramid, nylon, polycarbonate, polyphenylene sulfide, polyether sulfone, polysulfone, polyether ether ketone, liquid crystal polymer, bio nanofibers and the like.

When depositing a fluorescent substance on the said resin film, the resin film containing a polyimide is suitable from a heat resistant viewpoint.
The thickness of the resin film is preferably 20 to 1000 μm, more preferably 50 to 750 μm. By setting the thickness of the support to 50 μm or more, the handling property after forming the phosphor layer is improved. Further, by setting the thickness of the support to 750 μm or less, it becomes easy to process the functional layers such as the reflective layer, the conductive layer, the easy adhesion layer, etc. by roll to roll, and the productivity It is very useful from the viewpoint of improvement.

Phosphor layer 15
In the present invention, the term “phosphor” refers to a phosphor that emits light when atoms are excited when it is 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 and visible light and emits it.

  In the phosphors used in the present invention, various phosphor matrix compounds known in the prior art, and various compounds formed by doping these phosphor matrix compounds with suitable activators known in the prior art may be used. it can.

  For example, one containing a halide of an alkali metal, a halide of an alkaline earth metal and a halide of a rare earth element as a phosphor matrix compound can be mentioned. Here, among the halides of alkaline earth metals, fluorides are generally insoluble in water while many of the other halides are high in water solubility and tend to cause deliquescent problems. . Thus, as the alkaline earth metal halide, halides other than fluoride can be mentioned.

  The halogen constituting these halides is not particularly limited as long as it gives a deliquescent halide capable of forming a columnar crystal and functioning as a phosphor, but usually includes chlorine, bromine and iodine. In the case of alkali metal halides and lanthanoid halides, fluorine can also be a constituent halogen. However, in many cases, halogens constituting these halides are preferably bromine and iodine, with iodine tending to be particularly preferable.

  Examples of the alkali metal include lithium, sodium, potassium, rubidium and cesium, preferred examples of which include sodium and cesium, with cesium being particularly preferred.

  Examples of alkaline earth metals include beryllium, magnesium, calcium, strontium and barium, and preferred examples of these include calcium, strontium and barium.

In addition, examples of rare earth elements include scandium, yttrium and various lanthanoid elements, and preferred examples thereof include lanthanum and cerium.
In addition, as an example of a suitable fluorescent substance, what contains the halide of the alkali metal which has a crystal structure of a cubic system as a fluorescent substance matrix compound is mentioned.
These compounds may be used alone or in combination of two or more.

  In the present invention, the expression “phosphor based on X” is sometimes used, but this includes X as a phosphor matrix compound regardless of whether the activator is doped or not. Such phosphors may be made only of X, or those obtained by doping an activator with respect to X (that is, those containing X and an activator) ) May be.

Here, in the present invention, sodium iodide (NaI), cesium iodide (CsI), cesium bromide (CsBr) and lanthanum bromide are preferable examples of such a phosphor matrix compound constituting the phosphor. Phosphors such as (LaBr ₃ ) and strontium iodide (SrI) can be mentioned. Among them, cesium iodide (CsI) has a relatively high conversion rate from visible light to X-ray, and the phosphor can be easily formed into a columnar crystal structure by vapor deposition. Scattering can be suppressed and the thickness of the phosphor layer can be increased. Therefore, it is particularly preferable to use cesium iodide (CsI) as a phosphor matrix compound.

Further, as other suitable phosphor matrix compounds which can constitute a phosphor, halides of alkaline earth metals such as calcium halide, strontium halide, cesium iodide iodide (CsBa ₂ I ₅ ), cerium bromide, odor Also included are halides of lanthanides such as lanthanum fluoride. Here, strontium iodide and strontium bromide are mentioned as an example of strontium halide, and calcium iodide and calcium bromide are mentioned as an example of calcium halide.

Here, in the present invention, use of the above-described phosphor matrix compound such as CsI as the phosphor constituting the scintillator layer 12 is not prevented as it is. However, from the viewpoint of sufficiently securing the light emission efficiency, it is preferable to use, as the phosphor 120, a phosphor formed by doping various activators with respect to the phosphor matrix compound. As such an activator, for example, an activator such as thallium (Tl), europium (Eu), indium (In), lithium (Li), potassium (K), rubidium (Rb), sodium (Na) and the like are preferably mentioned. It is preferable to contain at least one or more of these. In the present invention, a phosphor obtained by using an additive containing a thallium compound and cesium iodide as a raw material, that is, thallium activated cesium iodide which is a phosphor obtained by doping cesium iodide with thallium is preferable. Thallium-activated cesium iodide (CsI: Tl) has a wide emission wavelength from 400 nm to 750 nm and can be detected by a general-purpose light detection panel.
Here, in the present invention, the relative content of the activator in a portion functioning as a phosphor layer contributing to the emission of fluorescence in the scintillator layer 12 is preferably 0.1 to 3 mol%.

  In the present invention, the scintillator layer 12 is usually composed of phosphor columnar crystals formed by a vapor deposition method from a phosphor matrix compound and an activator, and preferably, a constant surface index of the phosphor columnar crystals. The degree of orientation based on the X-ray diffraction spectrum of the face having the surface is in the range of 80 to 100% regardless of the position in the layer thickness direction of the scintillator layer from the root close to the substrate of the phosphor columnar crystal.

In the present invention, the degree of orientation is more preferably in the range of 95 to 100%. Also, the constant surface index may be any of (100), (110), (111), (200), (211), (220), (311), etc., but (200) (Refer to page 42-46 for introduction to X-ray analysis (Tokyo Kagaku Dojin) for the surface index). As a result, independent pillars are obtained on the substrate side of the columnar crystals, scattering of light components generated in the fluorescent substance is suppressed, and the light is efficiently emitted toward the photoelectric conversion element. When combined with FOP, it is more effective because it propagates to a single fiber of FOP without optical loss. In the present invention, “the degree of orientation based on the X-ray diffraction spectrum of a surface of a certain surface index” means the ratio of the intensity Ix of a certain surface index to the total intensity I including the surface of the other surface index. Point to For example, the degree of orientation of the intensity I _{200 on} the (200) plane in the X-ray diffraction spectrum is “degree of orientation = I ₂₀₀ / I”. The surface index for determining the degree of orientation The method of measurement is, for example, X-ray diffraction (XRD). In X-ray diffraction, a crystalline substance is irradiated with specific X-rays of a specific wavelength, and the fact that diffraction satisfying the Bragg's equation occurs can be used to obtain knowledge on the identification of the substance, the structure of the crystal phase, etc. It is a versatile analysis method. Cu, Fe, Co, etc. are used as the targets of the irradiation system, and the output at the time of irradiation is generally about 0 to 50 mA and about 0 to 50 kV, depending on the device capacity.

  Further, in the present invention, the phosphor constituting the scintillator layer 12 has a shape of a columnar crystal in which scattering of emission light in the crystal can be suppressed by the light guide effect. Examples of methods for forming columnar crystals include vapor deposition. As the vapor deposition method, a vapor deposition method, a sputtering method, a CVD method, an ion plating method and the like can be used, but in the present invention, the vapor deposition method is particularly preferable.

  In the present invention, the scintillator layer 12 may be composed of one layer or two or more layers. That is, the scintillator layer 12 may be formed of only the phosphor layer, or is formed of the base layer and the phosphor layer, and the base layer and the phosphor layer are laminated in this order on the support 11 It may have the same structure. When the scintillator layer 12 includes two layers of an underlayer and a phosphor layer, these layers may be made of the same material as long as the phosphor matrix compound is the same, or may be made of different materials. It may be one. That is, the scintillator layer 12 may be a single layer consisting entirely of the phosphor matrix, or the whole may be a single layer comprising the phosphor matrix compound and the activator, and the phosphor matrix compound And a phosphor layer containing a phosphor matrix compound and an activator. The underlayer comprising a phosphor matrix compound and a first activator, and fluorescence It may consist of a fluorescent substance layer containing a body base material compound and a 2nd activator.

  However, in the present invention, as a suitable scintillator layer 12, a scintillator layer consisting only of a phosphor layer consisting of a phosphor matrix compound and an activator, and a phosphor layer consisting of a phosphor matrix compound and an activator And a scintillator layer including an underlayer comprising a phosphor matrix compound and an activator, wherein a phosphor layer comprising the phosphor matrix compound and the activator, a phosphor matrix compound and the activator, Particularly preferred is a scintillator layer comprising an underlayer comprising

  Thus, in a preferred embodiment of the present invention, the scintillator layer 12 is composed of a phosphor layer containing a phosphor consisting of a phosphor matrix compound and an activator, but the scintillator 11 and the phosphor layer It is preferable that an undercoat layer is provided between the phosphor base compound and the activator and the porosity is larger than that of the phosphor layer.

  The relative content of the activator in the underlayer is preferably 0.01 to 1 mol%, more preferably 0.1 to 0.7 mol%. In particular, it is very preferable that the relative content of the activator of the underlayer is 0.01 mol% or more in terms of the improvement of the light emission luminance of the scintillator panel 10 and the storage stability. In addition, it is very preferable that the relative content of the activator in the underlayer is lower than the relative content in the phosphor layer, and the molar ratio of the relative content of the activator in the underlayer to the relative content of the activator in the phosphor layer The ratio ((relative content of activator in base layer) / (relative content in phosphor layer)) is preferably 0.1 to 0.7.

  As a method of forming a phosphor columnar crystal, a step of forming a base layer having a porosity lower than that of the phosphor layer on the surface of the substrate in order to satisfy the requirement for the surface index, and a surface of the base layer It is preferable that it is a manufacturing method of the aspect including the process of forming fluorescent substance by vapor deposition method. The void ratio in this patent refers to the ratio of the area of the void to the total of the cross-sectional area of the columnar crystal and the area of the void in the cross section obtained by cutting the phosphor layer parallel to the support. The porosity is determined by cutting the phosphor layer of the scintillator panel parallel to the support, and scanning electron micrographs of cross sections by binarizing the phosphor portion and the void portion using image processing software. be able to. The thickness of the phosphor layer (phosphor layer) is preferably 100 to 800 μm, and more preferably 120 to 700 μm from the viewpoint that the characteristics of luminance and sharpness can be obtained in a well-balanced manner. The thickness of the underlayer is preferably 0.1 μm to 50 μm, and more preferably 5 μm to 40 μm from the viewpoint of maintaining high brightness and sharpness.

Adhesion layer 16
An adhesive layer is formed between the support and the phosphor layer. As the adhesive layer, one made of a combination of one or more of resin, metal oxide and metal is used.

  Specific examples of the resin material constituting the adhesion layer include polyurethane, vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, butadiene-acrylonitrile Copolymer, polyamide resin, polyvinyl butyral, polyester, cellulose derivative (such as nitrocellulose), styrene-butadiene copolymer, various synthetic rubber resins, phenol resin, epoxy resin, urea resin, melamine resin, phenoxy resin, silicone Resin, acrylic resin, urea formamide resin etc. are mentioned. Among them, polyurethane, polyester, silicone resin, fluorocarbon resin, acrylic resin, and polyvinyl butyral are preferably used. Moreover, these 2 or more types can also be mixed and used.

The metal oxide constituting the adhesion _layer, such as SiO 2, TiO ₂ and the like. When the metal oxide layer is formed, it may be formed of a plurality of oxide layers.
As a metal material which comprises an adhesion layer, it is preferred to contain metal materials, such as aluminum, silver, platinum, palladium, gold, copper, iron, nickel, chromium, cobalt, and stainless steel. Among them, it is particularly preferable to use aluminum or silver as a main component from the viewpoint of reflectance and corrosion resistance. Also, two or more of such metal materials may be used.

  In the present invention, as the adhesive layer, one in which a filler is dispersed in a binder made of the above-mentioned resin material is preferable. In addition, the particle diameter and the compounding quantity of a filler are suitably selected in consideration of the thickness of an adhesion layer to form, an optical characteristic, etc.

As the filler, known inorganic powders and organic powders can be appropriately selected and used. Examples of the inorganic powder include titanium oxide, boron nitride, SnO ₂ , SiO ₂ , Cr ₂ O ₃ , α-Al ₂ O ₃ , α-Fe ₂ O ₃ , α-FeOOH, SiC, cerium oxide, corundum, artificial diamond , Stone meteorites, garnets, micas, silicas, silicon nitrides, silicon carbide, TiO ₂ (anatase type, rutile type), MgO, PbCO ₃ · Pb (OH) ₂ , BaSO ₄ , Al ₂ O ₃ , M (II) FX (However, M (II) is at least one atom selected from the respective atoms of Ba, Sr and Ca, and X is a Cl atom or a Br atom), CaCO ₃ , ZnO, Sb ₂ O ₃ , ZrO ₂ Litopon (BaSO ₄ · ZnS), magnesium silicate, basic lead silicic acid, basic lead phosphate, aluminum silicate and the like can be used. Examples of the organic powder include carbon black, pigments and the like in addition to powders such as three-dimensionally crosslinked polymethyl methacrylate, polystyrene and Teflon (registered trademark). These powders may be surface treated.

  The adhesive layer preferably has a function of absorbing or reflecting electromagnetic waves, and in the case of reflection, light scattering particles, in the case of absorption, light absorbing particles are preferably dispersed in a resin binder as a filler. (Such an adhesion layer is called a coating type adhesion layer). As described above, the adhesion layer having the function of absorbing or reflecting an electromagnetic wave is for absorbing or reflecting the electromagnetic wave emitted from the phosphor to enhance the light extraction efficiency. This makes it possible to construct a scintillator excellent in high brightness and sharpness.

  The light scattering particle has a function of improving the sharpness by preventing the light diffusion of the emission light generated in the phosphor layer. It has the function of improving the sensitivity by effectively returning the emitted light into the columnar crystals of the phosphor layer.

The light scattering particle is not particularly limited as long as it is a particulate material having a refractive index different from that of the resin material constituting the binder constituting the adhesive layer, and the material is, for example, TiO ₂ (anatase type, rutile Type), MgO, PbCO ₃ · Pb (OH) ₂ , BaSO ₄ , Al ₂ O ₃ , M (II) FX (where M (II) is at least one atom selected from Ba, Sr and Ca atoms) X is a Cl atom or a Br atom), CaCO ₃ , ZnO, Sb ₂ O ₃ , SiO ₂ , ZrO ₂ , Y ₂ O ₃ , lithopone (BaSO ₄ · ZnS), magnesium silicate, basic silica White pigments such as lead sulfate, basic lead phosphate and aluminum silicate can be used. Since these light scattering particles have high hiding power and large refractive index, by reflecting and refracting light, light emitted from the scintillator can be easily scattered and the sensitivity of the obtained panel can be remarkably improved.

  As other light scattering particles, for example, glass beads, resin beads, hollow particles in which hollow portions exist in the particles, multi-hollow particles in which many hollow portions exist in the particles, porous particles, etc. are also used. Can.

Glass beads preferably have a higher refractive index, for example, BK7 (n = about 1.5, n is a relative refractive index, the same applies hereinafter); LaSFN 9 (n = about 1.9); SF11 (n = about 1). 8); F2 (n = about 1.6); BaK1 (n = about 1.6); barium titanate (n = about 1.9); high refractive index blue glass (n = about 1.6 to 1. 7); TiO ₂ -BaO (n = about 1.9 to 2.2); borosilicate (n = about 1.6); or chalcogenide glass (n = about 2 or more) . Examples of the resin beads include acrylic particles, polyester resin particles, polyolefin particles, silicon particles, etc. Specifically, Chemisnow (registered trademark) (manufactured by Soken Chemical Co., Ltd.), silicon resin KR series, etc. (manufactured by Shin-Etsu Chemical Co., Ltd.) And Techpolymer (registered trademark) (manufactured by Sekisui Plastics Co., Ltd.) can be suitably used.

  In particular, white pigments such as titanium oxide have high hiding power and large refractive index, and by reflecting and refracting light, light emitted from the scintillator can be easily scattered and the sensitivity of the scintillator panel can be significantly improved. . As the white pigment, those described above can be used and the present invention is not limited thereto. Among them, titanium oxide is preferable.

As a crystal structure of titanium oxide, either rutile type or anatase type can be used, but rutile type is preferable because the ratio to the refractive index of the resin is large and high brightness can be achieved.
As such titanium oxide particles, specifically, for example, CR-50, CR-50-2, CR-57, CR-80, CR-90, CR-93, CR-95 manufactured by a hydrochloric acid method. , CR-97, CR-60-2, CR-63, CR-67, CR-58, CR-58-2, CR-85, R-820, R-830, R-930 manufactured by the sulfuric acid method. , R-550, R-630, R-680, R-670, R-580, R-780, R-780-2, R-850, R-855, A-100, A-220, W-10. (The above trade names: manufactured by Ishihara Sangyo Co., Ltd.) and the like.

  The primary particle diameter of the titanium oxide particles is preferably 0.1 to 0.5 μm, and more preferably 0.2 to 0.3 μm. Further, as the titanium oxide, one that has been surface-treated with an oxide such as Al, Si, Zr, Zn or the like is preferable in order to improve the affinity to the polymer, the dispersibility, or to suppress the deterioration of the polymer.

  The light absorbing particles are used to facilitate adjustment of the reflectance of the support to a desired value with high accuracy. Examples of light absorbing particles include light absorbing pigments. As the light absorbing pigment, various conventionally known pigments can be used. Specific examples thereof include ultramarine blue, prussian blue (ferrocyanide iron), phthalocyanine, anthraquinone, indigoid, carbonium, titanium black, carbon black and the like.

The adhesion layer may contain both the light scattering particles and the light absorbing particles described above.
The coating type adhesive layer can be formed by coating and drying a composition containing at least light scattering particles or light absorbing particles, a binder, and a solvent. The coating method is not particularly limited, but, for example, general methods such as gravure, die, comma, bar, dip, spray, and spin can be used.

  As a solvent used for producing a coating type adhesive layer, lower alcohols such as methanol, ethanol, n-propanol and n-butanol, chlorine atom-containing hydrocarbons such as methylene chloride and ethylene chloride, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone , Aromatic compounds such as toluene, benzene, cyclohexane, cyclohexanone and xylene, esters of lower fatty acids and lower alcohols such as methyl acetate, ethyl acetate and butyl acetate, dioxane, ethylene glycol monoethyl ester, ethylene glycol monomethyl ester, methoxypropanol Mention may be made of ethers such as propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate and the like and mixtures thereof.

  Also, if necessary, a dispersant may be used, and for example, polyhydric alcohols, amines, silicones, or surfactants can be used. The light scattering particles are preferably contained in an amount of 40 to 95% by mass in the adhesive layer, and particularly preferably contained in an amount of 60 to 90% by mass. The luminance is improved at 40% by mass or more, and the adhesion to the support or the phosphor is improved at 95% by mass or less.

  A dispersant may be used to improve the dispersibility of titanium oxide and the like. As the dispersant, for example, polyhydric alcohols, amines, silicones, or surfactants can be used.

The thickness of the adhesion layer is preferably 1 μm or more and 100 μm or less, more preferably 1 μm or more and 60 μm or less, when it is made of a resin.
Further, the thickness of the adhesion layer made of a metal oxide and a metal is preferably 0.005 to 0.3 μm, more preferably 0.01 to 0.2 μm, from the viewpoint of improving the luminance and the light extraction efficiency.

  It is preferable that the film thickness of a coating type contact | adherence layer is 10-500 micrometers. When the thickness of the adhesion layer is 10 μm or more, sufficient brightness can be obtained, and when the thickness is 500 μm or less, the smoothness is improved. When titanium oxide is contained, 40 to 95% by mass is preferably contained in the coating type adhesive layer, and 60 to 90% by mass is particularly preferable. The luminance is improved at 40% by mass or more, and the adhesion to the support or the phosphor is improved at 95% by mass or less.

  The formation method of a metal oxide layer can also be based on a well-known method. However, in the typical embodiment of the present invention, the vapor deposition method is generally used because it is easy to form a layered dense adhesion layer. As the vapor deposition method, known methods such as vapor deposition, sputtering, ion plating, plasma CVD and the like can be used, but sputtering and plasma CVD which can form a denser layer are preferable.

The method for forming the metal layer on the support is not particularly limited, such as vapor deposition, sputtering, or bonding of metal foils, but sputtering is preferred from the viewpoint of adhesion.
The support having the adhesion layer and the like formed as described above is installed in the support rotation mechanism using a vapor deposition apparatus having an evaporation source and a support rotation mechanism in a thermal vacuum vessel, and the support is The manufacturing method of the aspect which forms a fluorescent substance layer by the vapor phase deposition method including the process of vapor-depositing fluorescent substance material, rotating is preferable.

<Dampproof Protective Layer 13>
The moisture-proof protective layer may be formed of a single material, may be formed of a mixed material, or may be formed by using a plurality of layers of different materials in combination.

  The moisture-proof protective layer is mainly intended to protect the phosphor. Specifically, for example, in the case where the phosphor is cesium iodide (CsI), CsI is highly hygroscopic, and if left exposed, it absorbs water vapor in the air to deliquesce it. A moisture proof protective layer is provided for the purpose of prevention. The protective layer also has a function of blocking substances (such as halogen ions) emitted from the phosphor of the scintillator panel and preventing corrosion on the light receiving element side caused by the contact of the scintillator layer and the light receiving element.

  Further, in a mode in which the protective layer is formed by bonding the scintillator panel formed of columnar phosphor crystals of the scintillator panel and the photoelectric light receiving element with, for example, an adhesive or an optical oil, the adhesive or the optical oil is a columnar phosphor It also plays the role of a permeation prevention layer that prevents permeation between crystals.

  This protective layer can be formed using various materials. In the present invention, as the protective layer, materials of polyolefin type, polyacetal type, epoxy type, polyimide type, silicone type and polyparaxylylene type can be used. The polyparaxylylene system can be formed by the CVD method, and is also characterized by low water vapor and gas permeability, and is suitable for a CsI: Tl protective layer which is originally deliquescent. Here, polyparaxylylene is not only polyparaxylylene, but also polymonochloro-p-chloro-x-ylene, polydichloro-p-x-ylene, poly-tetra-chloro-p-x-ylene, poly-fluoro-p-xylylene, poly-fluoro-p-xylylene, poly-tetrachloroparaxylene , Polyfluoroparaxylylene, polydimethyl paraxylylene, polydiethyl paraxylylene and the like.

In the case of forming a moistureproof protective layer made of polyparaxylylene, the layer thickness on the surface and the side of the scintillator layer is preferably 2 μm or more and 15 μm or less.
Further, the moisture-proof protective layer may be further formed by laminating an inorganic substance such as SiC, SiO ₂ , SiN, Al ₂ O ₃ or the like by a vapor deposition method, a sputtering method or the like.
By covering the top of the scintillator layer, the side surface, and part of the FOP side surface with a protective layer such as polyparaxylylene, high moisture resistance can be obtained.

<Upper and Lower Absorbent Layer 17>
Between the scintillator layer 12 and the FOP 11 as shown in FIG. 1, a relief absorbing layer 17 may be provided to absorb the relief of the surface.
A resin transparent to visible light is used as the relief absorption layer. In the present invention, as such a resin, a hot melt has adhesiveness to other organic materials and inorganic materials in a heated and molten state, has no adhesiveness in a solid state at ordinary temperature, and does not contain a solvent or solvent. It is preferable to use a resin. As the hot melt resin, one having a polyolefin type, polyester type, polyamide type or the like as a main component is preferable, and in particular, it is desirable to use a hot melt resin based on a polyolefin resin as a material having high moisture resistance and light permeability. . Thus, it is preferable that the relief absorption layer using the hot melt resin is a single layer covering the entire surface in the planar direction of the scintillator layer and the FOP. This single layer eliminates interfaces at the time of transmission of visible light and minimizes unwanted light refraction and scattering.

The thickness of the relief layer is preferably 30 μm or less. Within this range, surface irregularities can be absorbed sufficiently, and there is no effect on light extraction.
By providing an optical compensation layer between the scintillator layer and the relief absorption layer, the difference in refractive index at the interface may be reduced to further reduce the amount of light reflected at the interface. .

  When the scintillator is irradiated with radiation, the radiation is converted to light in the phosphor of the scintillator and emits light. The light propagates in the columnar crystals of the phosphor in the direction of the relief absorption layer or the FOP. Then, the light propagated in the phosphor reaches the substantially conical wall surface of the tip portion of the columnar crystal of the phosphor, but if the optical compensation layer is formed as described above, most of the light is in the optical compensation layer As it enters, it is possible to further reduce the amount of light reflected at the interface.

  The optical compensation layer is preferably formed of a thermosetting resin that is cured by the application of heat. As a thermosetting resin, an acrylic resin, an epoxy resin, a silicone resin etc. are used preferably. Also, instead of forming the optical compensation layer with a solid such as a cured resin, it is also possible to form it with a transparent liquid or gel-like substance. Furthermore, it is also desirable that the optical compensation layer be formed using an adhesive. As the adhesive, for example, a cold setting adhesive such as an acrylic type, an epoxy type and a silicone type can be used. In particular, rubber-based adhesives can be used as the elastic adhesive resin. As a resin of a rubber adhesive, a block copolymer type such as styrene-isoprene-styrene, a synthetic rubber adhesive such as polybutadiene and polybutylene, a natural rubber and the like can be used. One-component RTV rubber KE420 (manufactured by Shin-Etsu Chemical Co., Ltd.) is preferably used as an example of a commercially available rubber adhesive.

<Method of manufacturing scintillator panel>
The scintillator panel 10 according to the present invention is not particularly limited in its production method as long as the object of the present invention is not impaired, and basically it can be the same method as a conventionally known scintillator panel production method.

  Specifically, a scintillator layer composed of a phosphor having a columnar structure is formed on a support on which an adhesion layer is formed according to a conventionally known method, and then, a relief absorption layer is interposed as necessary. After bonding with FOP, a scintillator panel can be obtained by forming a moisture-proof protective layer.

The formation of the adhesion layer can be carried out by the method described in the above "adhesion layer" section.
In the present invention, the phosphor is preferably formed by a vapor phase method, and specifically, is preferably formed by a vapor deposition method.

Formation of Scintillator Layer The scintillator layer is formed by using a vapor deposition apparatus having an evaporation source and a substrate rotating mechanism in a vacuum vessel, installing a support on the support rotating mechanism, and rotating the support while making the phosphor material The manufacturing method of the aspect which forms a fluorescent substance layer by the vapor phase deposition method including the process to vapor-deposit is preferable.
Hereinafter, an embodiment of the present invention will be described with reference to FIG.

  In the vicinity of the bottom of the interior of the vacuum vessel 32, evaporation sources 38a and 38b are disposed at mutually opposing positions on the circumference of a circle centered on a center line perpendicular to the support 34. In this case, the distance between the support 34 and the evaporation sources 38a and 38b is preferably 100 to 1500 mm, more preferably 200 to 1000 mm. The distance between the center line perpendicular to the support 34 and the evaporation sources 38a and 38b is preferably 100 to 1500 mm, more preferably 200 to 1000 mm.

  In the production apparatus, it is also possible to provide three or more (eight, sixteen, twenty-four, etc.) evaporation sources, and the evaporation sources may be arranged at equal intervals, and the intervals may be set. You may change and arrange. Also, the radius of the circle centered on the center line perpendicular to the support 34 can be arbitrarily determined.

  The evaporation sources 38a and 38b may be made of an alumina crucible in which a heater is wound, in order to contain the phosphor and heat it by resistance heating, or may be made of a boat or a heater made of a refractory metal. It is good. In addition to resistance heating, the method of heating the phosphor may be heating with an electron beam, heating by high frequency induction, etc. In the present invention, it is easy to handle with a relatively simple configuration, inexpensive, and From the viewpoint of being applicable to a large number of substances, a method of direct current flow and resistance heating, and a method of indirect resistance heating of a crucible with a surrounding heater are preferable. Further, the evaporation sources 38a and 38b may be molecular beam sources by a molecular source epitaxial method.

  According to the above manufacturing method, by providing the plurality of evaporation sources 38a and 38b, the overlapping portions of the vapor flows of the evaporation sources 38a and 38b are rectified and the crystallinity of the phosphor deposited on the surface of the support 34 is determined. It can be made uniform. At this time, since the vapor flow is rectified at a large number of locations as the number of evaporation sources is provided, the crystallinity of the phosphor can be made more uniform in a wider range. In addition, by arranging the evaporation sources 38a and 38b on the circumference of a circle centered on the center line perpendicular to the support 34, the effect that the crystallinity becomes uniform due to the rectification of the vapor flow is obtained. Can be obtained isotropically on the surface of

  The support holder 35 holds the support 34 so that the surface of the support 34 on which the phosphor layer is to be formed faces the bottom of the vacuum vessel 32 and is parallel to the bottom of the vacuum vessel 32. It has become.

  Further, the support holder 35 is preferably provided with a heater (not shown) for heating the support 34. By heating the support 34 with this heater, the adhesion of the support 34 to the support holder 35 is strengthened, and the quality of the phosphor layer is adjusted. In addition, the adsorbate on the surface of the support 34 is detached and removed to prevent the generation of an impurity layer between the surface of the support 34 and the phosphor.

  Moreover, you may have a mechanism (not shown) for circulating a heat carrier or a heat carrier as a heating means. This means is suitable for deposition while maintaining the temperature of the support 34 at a relatively low temperature of 50 to 150 ° C. during deposition of the phosphor.

  Moreover, you may have a halogen lamp (not shown) as a heating means. This means is suitable for deposition while maintaining the temperature of the support 34 at a relatively high temperature of 150 ° C. or higher at the time of deposition of the phosphor.

  Furthermore, the support holder 35 is provided with a support rotation mechanism 36 for rotating the support 34 in the horizontal direction. The support rotation mechanism 36 supports the support holder 35 and rotates the support 34. The support rotation shaft 37 is disposed outside the vacuum vessel 32 and a motor serving as a driving source of the support rotation shaft 37 (shown in FIG. It is composed of

  In the vapor deposition apparatus, in addition to the above configuration, a vacuum pump is disposed in a vacuum vessel. The vacuum pump exhausts the gas present inside the vacuum vessel, and two or more types of vacuum pumps having different operating pressure regions may be arranged to evacuate to the high vacuum region. As a vacuum pump, a rotary pump, a turbo molecular pump, a cryopump, a diffusion pump, a mechanical booster or the like can be used.

  In order to adjust the pressure in the chamber, a mechanism capable of introducing a gas into the vacuum vessel is provided. Generally, an inert gas such as Ne, Ar, Kr, etc. is used as the gas to be introduced. The pressure in the vacuum vessel may be adjusted by the amount of gas introduced while evacuating the inside of the vacuum vessel with a vacuum pump, or after evacuation is performed until the vacuum becomes higher than the desired pressure, the evacuation is stopped. Then, it may be adjusted by introducing a gas to a desired pressure. Further, the pressure in the vacuum container may be controlled by adjusting the displacement of the pump by providing a pressure control valve between the vacuum container and the vacuum pump.

  In addition, a shutter 39 that shuts off the space from the evaporation sources 38a and 38b to the support 34 is provided horizontally openable and closable between the evaporation sources 38a and 38b and the support 34 by the shutter 39. In the evaporation sources 38a and 38b, it is possible to prevent substances other than the object attached to the surface of the phosphor from evaporating in the initial stage of deposition and adhering to the support 34.

The method for producing the scintillator panel of the present invention using the above-mentioned production apparatus 31 will be further described.
First, the support 34 is attached to the support holder 35. In the vicinity of the bottom surface of the vacuum vessel 32, the evaporation sources 38a and 38b are disposed on the circumference of a circle centered on a center line perpendicular to the support 34. Next, a crucible, a boat or the like is filled with two or more phosphor matrix compounds (CsI: no activator) and an activator (TlI), and set as an evaporation source.

  Preheating may be performed to remove impurities in the filled phosphor base material and the activator before deposition. The preheating is desirably equal to or lower than the melting point of the material used. For example, in the case of CsI, 50-550 degreeC is preferable and 100-500 degreeC of preheating temperature is more preferable. In the case of TlI, 50 to 500 ° C is preferable, and 100 to 500 ° C is more preferable.

  The inside of the vapor deposition apparatus is once evacuated, Ar gas is introduced to adjust the degree of vacuum, and then the substrate is rotated. The substrate rotation is preferably 2 to 15 revolutions / minute, and more preferably 4 to 10 revolutions / minute, depending on the size of the apparatus. Next, the crucible of the phosphor matrix compound (CsI: no activator) is heated to vapor-deposit the phosphor, thereby forming an underlayer (first phosphor layer). At this time, the substrate temperature is preferably 5 to 100 ° C., and more preferably 15 to 50 ° C. The thickness of the underlayer depends on the crystal diameter and the thickness of the phosphor layer, but is preferably 0.1 to 50 μm. Next, heating of the substrate is started, the substrate temperature is heated to 150 to 250 ° C., and evaporation of the remaining phosphor matrix compound (CsI: no activator) and activator (TlI) is started. At this time, it is preferable to evaporate the phosphor matrix compound at a deposition rate faster than that of the underlayer, in consideration of productivity. Although it depends on the thickness of the underlayer and the phosphor layer, it is preferable to deposit at a speed 5 to 100 times faster than at the time of depositing the underlayer, and more preferable to deposit 10 to 50 times. The method of evaporation of the activator may be evaporation of the activator alone, but a source of CsI and TlI mixed is prepared, and the CsI is not evaporated and heated to a temperature (e.g. 500 ° C.) at which only TlI is evaporated. It may be evaporated.

The support that has been heated at the time of vapor deposition needs to be cooled in order to remove it because of the high temperature. By setting the average cooling rate in the step of cooling the phosphor layer to 80 ° C. in the range of 0.5 ° C. to 10 ° C./min, the substrate can be cooled without damage. For example, it is particularly effective when a relatively thin substrate such as a polymer film having a thickness of 50 μm to 500 μm is used as a support. It is particularly preferable that the cooling step be performed under an atmosphere of a vacuum degree of 1 × 10 ⁻⁵ Pa to 0.1 Pa. In addition, means for introducing an inert gas such as Ar or He into the vacuum chamber of the vapor deposition apparatus may be provided at the time of the cooling step. The average cooling rate referred to herein is the time and temperature during cooling to 80 ° C. from the start of cooling (at the end of deposition) and continuously measured, and the cooling rate per minute during this time is determined. .

After completion of the deposition, the phosphor layer may be heat treated. In addition, in the deposition method, reactive deposition may be performed by introducing a gas such as O ₂ or H ₂ as necessary.
In the present invention, in the support on which the phosphor layer is formed, the support, the adhesion layer, and the phosphor layer preferably have the same dimensions. For this reason, in the manufacture of a scintillator panel, the support on which the phosphor layer is formed is cut into the product size together with the support after forming the phosphor layer larger than the product size on the support larger than the product size Is preferred. The productivity can be improved by cutting out a plurality of phosphor layer-attached supports from the support on which the phosphor layer is formed.
Examples of the method for cutting the plurality of phosphor layer-attached supports include a method using a punching blade, a push cutter, a cutter knife, scissors, a laser beam, and the like.

In order to stack the bonded scintillator layer with FOP and the FOP, for example, they are stacked via a relief absorption layer. A sheet made of a hot melt resin is sandwiched between the phosphor layer and the FOP as a relief absorption layer, and it is possible to fix while absorbing the fine relief of the surface of the phosphor layer by heating in a pressurized state. is there.

The hot melt resin sheet used as a relief layer has a structure in which peelable protective layers are disposed on both sides of the hot melt resin sheet, and the protective layer is peeled off and then subjected to a heating step to be attached. To achieve the adherence of
An outline of the method of laminating the phosphor layer and the FOP will be described with reference to FIG.

  As shown in the upper part of FIG. 3, in the lamination procedure of the phosphor layer and the FOP, first, the hot melt resin sheet is cut into the same shape as the FOP, and the protective layer on the FOP side is peeled off. The surface and FOP are laminated, and temporarily fixed (temporarily bonded) in a temperature range of 60 ° C to 80 ° C under pressure equivalent to atmospheric pressure, and then the protective layer on the phosphor layer side of the hot melt resin sheet is peeled off The hot melt resin sheet and the phosphor layer of the scintillator are laminated, and main fixation (final bonding) is performed in a temperature range of 80 ° C. to 100 ° C. under pressure equivalent to atmospheric pressure.

  A laminated body in which the temporarily fixed hot melt resin sheet and FOP, and the permanently fixed FOP · hot melt resin sheet and phosphor layer are laminated at the time of fixing is enclosed in a bag-like thermo-compression bondable film. The bag is thermocompression-bonded under vacuum to seal the laminate, and then the laminate is taken out of the bag and heated to a predetermined temperature range in a pressure-adhered state under atmospheric pressure to temporarily fix and fix it. Be done.

  Also, as shown in the lower part of FIG. 3, the hot melt resin sheet from which the protective layer was peeled off was temporarily fixed in the temperature range of 60 ° C. to 80 ° C. under pressure equivalent to atmospheric pressure to the phosphor layer of the scintillator before cutting. Temporarily bond them together to make a phosphor / hot melt resin laminate. After making this into a phosphor / hot melt resin laminate of the same size as FOP by the above-mentioned cutting method, the protective layer of the hot melt resin sheet is peeled off (not shown), placed on the FOP and laminated, and atmospheric pressure The main fixing (final bonding) may be performed in a temperature range of 80 ° C. to 100 ° C. under a considerable pressure. Also in this case, the thermocompression-bonding film bag is used as described above at the time of fixing.

Method of forming a moistureproof protective layer A moistureproof protective layer is formed on the top, side and FOP side of the scintillator layer.
A method of forming the moisture proof protective layer is shown in FIG.
FIG. 4A schematically shows a method of forming the moisture-proof protective layer so as to have a predetermined slope by the CVD method.
A jig having a height such that only the FOP portion is buried and a recess having a predetermined gap around the FOP is prepared for the scintillator bonded to the FOP.

  The FOP to which the scintillator layer is adhered is placed on the upper surface of the recess, and the moisture-proof protective layer is deposited by the CVD method, whereby the moisture-proof layer is formed on the surface and side of the scintillator layer and part of the FOP side. In the CVD method, the inside of the void is not uniformly deposited, but is deposited so as to be gradually thinner. For this reason, the lower end of the FOP side surface is not vapor deposited, and a moisture-proof layer having a predetermined slope is formed. The thickness of the lower end corresponds to T2 shown in FIG. The slope transition portion is a side surface that transitions from the scintillator to the FOP, and the slope may start in the middle of the side surface of the FOP.

The inclination of the moisture-proof protective layer can be adjusted by the width and depth of the air gap around the FOP.
After forming the moisture-proof layer, polishing may be performed to a predetermined thickness.
In the embodiment of the present invention, since the moisture-proof protective layer has a high bonding strength with the FOP, the moisture-proof protective layer does not peel off, and the moisture resistance is not impaired.

In the case of chamfering the FOP, chamfering may be performed after forming the moisture-proof protective layer.
FIG. 5 is a schematic cross-sectional view of one embodiment of an apparatus used for forming a protective layer, which is an example of forming a protective layer made of polyparaxylylene on the surface of a scintillator.

  The CVD deposition apparatus 45 includes a vaporization chamber 51 for inserting and vaporizing diparaxylylene, which is a raw material of polyparaxylylene, a thermal decomposition chamber 52 for heating and heating the vaporized diparaxylylene, and scintillating diparaxylylene in a radicalized state. It comprises a deposition chamber 53 for depositing the upper phosphor layer 122, a cooling chamber 54 for deodorizing and cooling, and an exhaust system 55 having a vacuum pump. Here, as shown in FIG. 5, the deposition chamber 53 has an inlet 53a for introducing polyparaxylylene radicalized in the thermal decomposition chamber 52 and an outlet 53b for discharging excess polyparaxylylene. It has a turntable (vapor deposition table) 53c for supporting a sample on which polyparaxylylene is to be deposited.

First, the phosphor layer 122 of the scintillator panel 42 is installed on the turntable 53 c of the deposition chamber 53 with the phosphor layer 122 facing upward.
Next, diparaxylylene, which is vaporized by heating to 175 ° C. in the vaporization chamber 51 and heated to 690 ° C. in the thermal decomposition chamber 52, is introduced into the vapor deposition chamber 53 from the introduction port 53a, and the phosphor layer is formed. A protective layer (polyparaxylylene) 123 is vapor-deposited to a thickness of 3 μm on 122. In this case, the inside of the vapor deposition chamber 53 is maintained at a degree of vacuum of 13 Pa. Also, the turntable 53c is rotated at a speed of 4 rpm. In addition, the excess polyparaxylylene is discharged from the discharge port 53b and led to the exhaust system 55 having a cooling chamber 54 for performing deodorization and cooling and a vacuum pump.

<Use>
The scintillator panel of the present invention can be applied to various forms of X-ray imaging systems. Among them, as a particularly suitable application, it can be used as a radiation detector in combination with a light detection panel.

[Radiation detector]
It can be set as the radiation detector which combines an optical detection panel with the above-mentioned scintillator panel which has a scintillator layer. In such a radiation detector, the X-ray from the outside is converted into light by the scintillator layer, and this light is converted into an electrical signal by the light detection panel and can be output to the outside in a form associated with position information It will be in the state.

  The light detection panel used in the present invention has a role of converting light into an electric signal and outputting the light to the outside, and a conventionally known one can be used, and the configuration thereof is not particularly limited, Usually, the substrate, the image signal output layer, and the photoelectric conversion element are laminated in this order.

  Among them, the photoelectric conversion element has a function of absorbing light generated in the scintillator layer and converting it into the form of charge. Here, the photoelectric conversion element may have any specific structure as long as it has such a function. For example, the photoelectric conversion element used in the present invention can be composed of a transparent electrode, a charge generation layer which is excited by incident light to generate a charge, and a counter electrode. Any of those conventionally known can be used as the transparent electrode, the charge generation layer and the counter electrode. In addition, the photoelectric conversion element used in the present invention may be composed of a suitable photo sensor, for example, a plurality of photodiodes may be two-dimensionally arranged, or a CCD It may consist of two-dimensional photosensors such as Charge Coupled Devices (CMOS) and Complementary metal-oxide-semiconductor (CMOS) sensors.

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto.
Example 1
A 125 μm thick polyimide film is used as a substrate, and the surface on which a phosphor is to be formed as an adhesive layer is coated with Bayon resin (made by Toyobo Co., Ltd.), which is a crystalline polyester, to 3 μm. As a support for vapor deposition. The CsI phosphor was deposited on the support under vacuum. The film thickness of CsI was 300 μm.

The deposited scintillator was cut into the same shape as FOP, and a 30 μm thick hot melt sheet and the scintillator were laminated in the following two-step procedure on a 3 mm thick FOP.
First, the above-mentioned FOP and a laminate of the hot melt sheets laminated (a laminated body A) are sealed in a bag made of a thermocompression-bondable film sheet, and the film sheet is thermocompressed under vacuum to form a laminated body A Sealed. After the bag of the sealed film sheet is returned to atmospheric pressure, the laminate A is taken out and heated at 60 ° C. for 1 hour while applying pressure by atmospheric pressure, the hot melt sheet is melted and the FOP and the hot melt The sheet was temporarily fixed.

  Subsequently, the phosphor surface (light emitting surface) of the scintillator is disposed on the FOP / hot melt sheet laminate (laminate B) in a direction to face the hot melt sheet in a bag made of a thermocompression-bondable film sheet. It was enclosed and heated at 80 ° C. for 1 hour under pressure contact in the same manner as described above to laminate the FOP and the scintillator.

  Attach a laminate of FOP, hot melt, and scintillator (hereinafter referred to as scintillator panel) to a jig in close contact with the visible light output surface side of the FOP, which is the opposite side of the scintillator adhesion surface, from polyparaxylylene under vacuum A moistureproof protective layer was formed by CVD. The thickness of the moistureproof protective layer made of polyparaxylylene was adjusted to 10 μm. The film thickness on the side surface is also 10 μm. After forming the moisture-proof protective layer made of polyparaxylylene, the scintillator panel was removed from the jig to realize a state in which the moisture-proof protective layer is not formed on the visible light exit surface of the FOP.

  In the present embodiment, the shape of the jig used when forming the moisture-proof protective layer made of polyparaxylylene is a hole structure having a gap of 10 to 100 μm with the scintillator panel, whereby the moisture-proof protective layer on the side face of the FOP It was adjusted so that the thickness of would become thin near the lower end. The lower end of the moistureproof protective layer made of polyparaxylylene was located at 0.5 mm from the visible light exit surface of the FOP.

  In the obtained scintillator panel, when the distance covered by the moistureproof protective layer on the side surface of the scintillator is A and the distance covered by the moistureproof protective layer in the thickness direction of the FOP is B, A is 0.6 mm and B is 3.0 mm Met. When the layer thickness of the moistureproof protective layer on the side of the scintillator is T1, and the layer thickness at the light emitting side end of the moistureproof protective layer on the side of the FOP is T2, T1 is 10 μm and T2 is 0.5 μm. Met.

When the scintillator panel on which the moistureproof protective layer made of polyparaxylylene is formed in this manner is disposed on a reading sensor having a CMOS element and the sharpness is measured, no FOP is bonded at each spatial frequency. It was found that the sharpness was improved to 110% with respect to the scintillator. The luminance was 70% compared to the scintillator without FOP bonding. In addition, when a moisture resistance test was performed in an environment of 40 ° C. and 70% RH, the sharpness after 196 hours did not change.
The evaluation in the examples was performed as follows.

Method of evaluating sharpness of scintillator panel Using an X-ray irradiator with a tube voltage set to 80 Kvp, X-rays are irradiated from the back surface of the scintillator panel (surface on which the scintillator layer is not formed) through a lead MTF chart. The image data detected by the CMOS flat panel was recorded on the hard disk. Thereafter, the recording of the image data 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. MTF is an abbreviation of Modulation Transfer Function, and at this time, a radiation image detector mounted with a scintillator panel manufactured in the same manner as in Example 1 except that FOP is not bonded is set to 100.

Method of evaluating sensitivity (brightness) of scintillator panel The method of evaluating sensitivity (brightness) of the scintillator panel is to use an X-ray irradiator with a tube voltage set to 80 Kvp and use an X-ray with a radiation image detector in the FPD The light receiving surface is irradiated, and from the obtained X-ray image data, an average signal value of the entire surface of the X-ray image is determined to be the sensitivity of the scintillator panel. At this time, an average signal value of a radiation image detector equipped with a scintillator panel manufactured in the same manner as in Example 1 except that FOP is not bonded is set to 100.

Moisture Resistance Test The humidity resistance test is conducted in an environment of 40 ° C. and 70% RH to evaluate the sharpness after 196 hours.

Example 2
In the preparation of the scintillator, the adhesion layer is formed using the Vyron resin containing titanium oxide in an amount of 40% by mass as a white pigment in the adhesion layer, and the phosphor layer is formed in the same manner as in Example 1. After that, FOP was pasted through hot melt to prepare a scintillator panel, and then a moisture-proof protective film was formed. It evaluated similarly to the obtained scintillator panel Example 1. As a result, the sharpness was reduced by 30% as compared with the scintillator without FOP bonding as in Example 1, but the brightness was 130% of that of the scintillator without FOP bonding, and a high brightness type scintillator was obtained. The sharpness was not changed by the moisture resistance test.

Example 3
When forming a scintillator, an adhesion layer was formed using a Vyron resin containing 40% by mass of carbon black as a black pigment in the adhesion layer, and a phosphor layer was produced in the same manner as in Example 1.

  Bonding to FOP was performed in the same manner as in Example 1 to form a moisture proof protective film, and a scintillator panel was produced. The obtained scintillator panel was evaluated for optical characteristics in the same manner as in Example 1. As a result, the sharpness is improved by 20% in comparison with the scintillator without FOP bonding, and the luminance is 60% in comparison with the scintillator without FOP bonding However, a highly sharp scintillator was obtained. The sharpness was not changed by the moisture resistance test.

Comparative Example 1
A laminate of scintillator and FOP is prepared by the same method as in Example 1, and instead of the jig used in the example, the entire laminate is placed on a smooth carbon plate and introduced into a CVD apparatus, A moisture-proof protective layer consisting of polyparaxylylene was formed under the same conditions as 1).

  Since the moistureproof protective layer made of polyparaxylylene integrally coats the scintillator / FOP bonded body and the carbon plate, the separation from the carbon plate was performed by separating the interface between the FOP and the carbon plate using a cutter.

  The moisture proof protective layer made of polyparaxylylene on the side of the scintillator has a thickness of 10 μm from the side of the polyimide support to the bottom of the side of the FOP, but the thickness of the moistureproof protective layer at the bottom of the FOP is not good According to the rule, a variation of 10 to 15 μm was observed.

  Such a scintillator had an initial performance equivalent to that of Example 1, but the moisture proof protective layer made of polyparaxylylene on the side of the FOP peeled off during the moisture resistance test, and the brightness and sharpness deteriorated.

Comparative Example 2
A laminate of scintillator and FOP is prepared in the same manner as in Example 1, and is supported by a support having a shape in which needle-like projections are arranged so as to support the radiation incident surface of the scintillator in points. A moisture-proof protective layer consisting of xylylene was formed.

  In the scintillator thus produced, a moistureproof protective layer made of polyparaxylylene having a thickness of 10 μm was also formed on the exit surface of the FOP. When the same optical characteristics as in Example 1 were inspected in this state, although the luminance and the moisture resistance did not particularly change, the sharpness deteriorated.

10 scintillator panel 11 fiber optic plate (FOP)
12 scintillator layer 13 moisture-proof protective layer 14 support 15 phosphor 16 adhesion layer 17 relief absorption layer

Claims (13)

A fiber optic plate (FOP) having a radiation incident surface and an emission surface, a scintillator for converting radiation provided on a light incident surface on the FOP into visible light, provided on the scintillator, the FOP A scintillator panel comprising a moisture-proof protective layer disposed in a form covering at least a part of the light-emitting diode, wherein the moisture-proof protective layer is not disposed on the light emitting surface of the FOP ,
When the distance covered by the moistureproof protective layer on the side surface of the scintillator is A, and the distance covered by the moistureproof protective layer in the thickness direction of the FOP is B, the relationship of A ≦ B is satisfied.
When the layer thickness of the moisture-proof protective layer on the side surface of the scintillator is T1, and the layer thickness at the emission-side end of the moisture-proof protective layer on the side surface of the FOP is T2, the relationship of T1> T2 is satisfied. Scintillator panel.   The scintillator panel according to claim 1, wherein the moisture-proof protective layer continuously covers at least a part of the scintillator surface and the entire side surface and the side surface of the FOP.   The scintillator comprises a support made of an organic film, an adhesion layer disposed on the radiation emission side of the support, and a phosphor layer having a columnar crystal structure and disposed on the adhesion layer-arranged surface of the support. The scintillator panel according to claim 1 or 2, characterized in that   The scintillator panel according to any one of claims 1 to 3, wherein the moisture-proof protective layer is made of paraxylylene polymer.   The scintillator panel according to any one of claims 1 to 4, wherein the scintillator and the FOP are in contact with each other via a relief absorption layer.   The scintillator panel according to claim 5, wherein the relief absorption layer is a layer made of a hot melt resin transparent to visible light.   The thickness of the said uneven | corrugated absorption layer is 30 micrometers or less, The scintillator panel of Claim 5 thru | or 6 characterized by the above-mentioned.   The scintillator panel according to any one of claims 5 to 7, wherein the relief absorbing layer is a single layer extending over the entire surface in the panel plane direction.   4. The scintillator panel according to claim 3, wherein the support, the adhesion layer, and the phosphor layer have the same dimensions in the planar direction.   The scintillator panel according to claim 3, wherein the adhesion layer is made of a combination of one or more of resin, metal oxide and metal.   The scintillator panel according to claim 3, wherein the adhesion layer has a function of absorbing or reflecting an electromagnetic wave generated in the phosphor layer.   The scintillator panel according to any one of claims 1 to 11, wherein a chamfering process is performed on at least an outer peripheral portion of an output surface of the FOP.   A radiation detector comprising the scintillator panel according to any one of claims 1 to 12.

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