JP2016136094A - Scintillator panel and radiation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scintillator panel with a moisture-proof protection layer having high adhesion strength on side faces of an FOP, which allows for maintaining good capability to protect a phosphor from moisture and achieving high luminance and high resolution.SOLUTION: A scintillator panel has an incident surface and an exit surface for radiation and comprises a fiber optic plate (FOP), a scintillator that is disposed on a light incident surface of the FOP to convert radiation into visible light, and a moisture-proof protection layer provided on top of the scintillator and arranged to cover at least a portion of the FOP, where the moisture-proof protection layer does not cover a light exit surface of the FOP.SELECTED DRAWING: Figure 1

Description

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

In recent years, radiation detectors that convert radiation transmitted from a radiation source through an imaging region of a subject into electric charges and generate a digital radiation image are used in medical practice for diagnosis of medical conditions. These radiation detectors include a scintillator system in which radiation is converted into visible light by a phosphor layer such as Gd ₂ O ₂ S or CsI, and then converted into electric charge by a photoelectric conversion element (PD), and X-rays represented by Se. The method is roughly divided into a method of directly converting X-rays into electric charges by a detection element, and among these, a scintillator method is highly noted.

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

  Since the phosphor material constituting the scintillator has deliquescence, it is protected from moisture by forming a moisture-proof protective layer made of polyparaxylylene or the like on the scintillator. Moisture permeates from the boundary surface between the phosphor and the substrate and the adhesive layer that bonds them, so that the moisture-proof protective layer is formed so as to cover not only the scintillator surface but also the FOP.

  However, FOP has a drawback of low adhesion to the moisture-proof protective layer. For this reason, Japanese Patent Application Laid-Open No. 2005-338067 (Patent Document 1) proposes providing an uneven surface on the FOP side wall surface in contact with the moisture-proof protective layer to prevent peeling of the protective layer.

  In JP 2011-257142 A (Patent Document 2), the adhesion between the FOP and the scintillator is improved by attaching the tip of the columnar crystal constituting the scintillator and the FOP with a double-sided adhesive film so as to face each other. It is disclosed.

  Japanese Patent Application Laid-Open No. 2010-32299 (Patent Document 3) discloses a phosphor layer formed on one surface of a substrate that converts radiation into visible light and a surface opposite to the one surface of the substrate including the surface of the phosphor layer. A moisture-proof layer is disclosed which covers a part of the other surface and is formed so that a layer thickness covering a part of the other surface of the substrate becomes thinner from the peripheral side to the center side of the substrate. Has been.

  However, when unevenness is provided on the side surface of the FOP in order to enhance the adhesion, the FOP is easily damaged and the fiber property of the FOP is lowered. In addition, in the method proposed above, the optical performance may decrease when the moisture-proof protective layer on the radiation incident side is thickened, and the adhesion strength of the moisture-proof protective layer on the FOP side surface is not necessarily high. There was a problem that peeling occurred.

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

  The present invention has been made in view of the above-described circumstances, and since there is little change in optical performance due to the moisture-proof protective layer on the radiation incident side, and the adhesion strength of the moisture-proof protective layer on the FOP side surface is high, An object of the present invention is to provide a scintillator panel and a radiation detector capable of maintaining high moisture-proof performance on the body and achieving both high luminance and high resolution.

The above-mentioned problem according to the present invention is solved by the following means.
That is, the scintillator panel according to the present invention has a radiation entrance surface and an exit surface, a fiber optics plate (FOP), and a scintillator that converts radiation provided on the light entrance surface on the FOP into visible light, In the scintillator panel, which is provided on the scintillator and includes a moisture-proof protective layer disposed so as to cover at least a part of the FOP, the moisture-proof protective layer is not disposed on the light emitting surface of the FOP. .

  It is preferable that the moisture-proof protective layer continuously covers the scintillator surface and the entire side surface and at least a part of the side surface of the FOP. When the distance covered by the moisture-proof protective layer on the side surface of the scintillator is A and the distance covered by the moisture-proof 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 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, it is preferable that T1> T2.

  The scintillator includes a support made of an organic film, an adhesion layer disposed on the radiation emitting side on the support, and a phosphor layer having a columnar crystal structure and disposed on the adhesion layer arrangement surface of the support. It is preferable.

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

Moreover, it is preferable that the said support body, the said contact | adherence layer, and the said fluorescent substance layer have the same dimension in a plane direction. The adhesion layer is preferably composed of one or more combinations of resin, metal oxide, and metal. The adhesion layer preferably has a function of absorbing or reflecting electromagnetic waves generated in the phosphor layer. Further, it is preferable that chamfering is performed on the outer peripheral portion of at least the exit surface of the FOP.
The radiation detector according to the present invention is characterized by using the scintillator panel described above.

In the present invention, the moisture-proof protective layer provided on the scintillator and arranged to cover at least a part of the FOP is not arranged on the light emission surface of the FOP. Thereby, even if the moisture-proof protective layer on the radiation incident side is thickened, the optical performance is not deteriorated. Further, since the moisture-proof protective layer on the side surface of the FOP is attached with a sufficient length, the adhesion strength to the side surface of the FOP is increased, so that the layer peeling is small.
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 having high luminance and high resolution can be provided.

FIG. 1 is a cross-sectional view schematically showing a scintillator panel according to the present invention. FIG. 2 is a schematic diagram showing one configuration of the phosphor vapor deposition apparatus used in the present invention. FIG. 3 is a schematic flow diagram showing a method for laminating the phosphor layer and the FOP. FIG. 4 is a schematic flow diagram showing a method for forming a moisture-proof protective layer. FIG. 5 shows a schematic cross-sectional view of one embodiment of the apparatus used for forming the protective layer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
Here, in this specification, the term “light” has an electromagnetic wave in a wavelength region ranging from an ultraviolet region to an infrared region centered on visible light, more specifically, a wavelength from 300 nm to 800 nm. Refers to electromagnetic waves. The term “phosphor” or “scintillator” refers to a phosphor that absorbs the energy of incident radiation such as X-rays and emits the “light”.

Further, the term “transparent” refers to the property that the “light” can be transmitted without causing significant reflection and scattering unless otherwise stated.
Hereinafter, a scintillator panel and a radiation detector according to the present invention, their components, and modes and modes for carrying out the present invention will be described in detail.

[Scintillator panel]
A basic configuration of a 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 moisture-proof protective layer 13 in this order. Here, in a typical aspect of the present invention, radiation incident on the scintillator panel 10 is performed from the moisture-proof protective layer 13 side of the upper surface of the FOP 11 toward the FOP 11 side. The protective layer 13, the scintillator layer 12, and the FOP 11 are arranged in this order.

  The moisture-proof protective layer 13 is disposed so as to cover at least a part of the FOP 11, and the moisture-proof protective layer is not disposed on the light emission surface of the FOP 11. By adopting such a configuration, peeling of the moisture-proof protective layer can be suppressed.

  It is preferable that the moisture-proof protective layer 13 continuously covers at least a part of the side surface of the FOP together with the scintillator surface and the entire side surface. Therefore, the FOP may be exposed at the lower end of the emission side of the FOP side surface.

  As shown in FIG. 1, when the distance covered by the moisture-proof 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 moisture-proof protective layer in the thickness direction is B (note that CB corresponds to an exposed portion and preferably has a relationship of C ≧ B) and A ≦ B. If it has this relationship, the contact | adherence area of the moisture-proof protective layer to FOP side surface will fully be ensured, and it will prevent peeling.

  The distance A corresponds to the thickness of the scintillator layer. In addition, when the scintillator layer 12 is comprised from the support body 14, the fluorescent substance 15, and the contact | adherence layer 16 which is one of the preferable aspects, the total thickness combining these corresponds to the distance A.

  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, it is preferable that T1> T2. The moisture-proof protective layer has a uniform layer thickness T1 on the side surface of the scintillator, but has an inclination so that the layer thickness becomes T2, as shown in FIG. 1, toward the emission side end of the FOP side surface. Even if it is a thing, thickness may reduce in steps. By adopting such a layer thickness configuration, the adhesion of the moisture-proof protective layer can be further increased, and peeling can be suppressed more significantly.

A relief absorbing layer 17 may be provided between the scintillator layer 12 and the FOP 11 as shown in FIG. The thickness of the undulation absorbing layer is not included in the distances A and B.
Hereinafter, each member constituting the present invention will be described.

<Fiber optics plate (FOP) 11>
A fiber optics plate (FOP) is an optical device in which optical fibers of several μm are bundled, and can transmit incident light to a photoelectric conversion element with high efficiency and low distortion. Further, FOP has a high radiation shielding effect, and it is also possible to prevent radiation damage to various elements constituting the photodetector used in the radiation image converter.

A commercially available FOP can be selected from the radiation shielding rate, visible light transmittance, and the like. The shape and size of the FOP can be appropriately set depending on the application of the scintillator panel 10 and the like, and the shape can be changed by chamfering or the like by a conventionally known method. If the FOP is chamfered, an effect of preventing cracks and breakage due to impact at the lower end of the FOP can be expected.
Here, the chamfering of the FOP may be performed before the scintillator layer 12 is formed, or may be performed after the scintillator layer 12 and the moisture-proof protective layer 13 are formed.

<Scintillator layer 12>
The scintillator layer 12 includes a support 14 made of an organic film, an adhesion layer 16 disposed on the radiation emitting side on the support, and a phosphor having a columnar crystal structure and disposed on the adhesion layer arrangement surface of the support. Layer 15.

  The support, the adhesion layer, and the phosphor layer preferably have the same dimensions in the planar direction. When having the same dimensions, the optical area equivalent to that at the center can be obtained even at the end portion, so that the effective area can be maximized.

Support 14
The support refers to a member that plays a role of holding 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. In addition, “elastic modulus” refers to the slope of the stress with respect to the strain amount in a region where the strain indicated by the standard line of the sample conforming to JIS-C2318 and the corresponding stress have a linear relationship using a tensile tester. Is the value obtained. This is a value called Young's modulus, and this Young's modulus is defined as an elastic modulus. The support preferably has an elastic modulus (E120) at 120 ° C. of 0.1 to 300 GPa, more preferably 1 to 100 GPa.

  Specific examples of the resin film having flexibility include polyethylene terephthalate, polyethylene naphthalate, cellulose acetate, polyamide, polyimide, polyetherimide, epoxy, polyamideimide, bismaleimide, fluororesin, and acrylic. , Polyurethane, aramid, nylon, polycarbonate, polyphenylene sulfide, polyethersulfone, polysulfone, polyetheretherketone, liquid crystal polymer, bio-nanofiber, and the like.

When vapor-depositing the phosphor on the resin film, a resin film containing polyimide is preferable from the viewpoint of heat resistance.
The thickness of the resin film is preferably 20 to 1000 μm, more preferably 50 to 750 μm. By making the thickness of the support 50 μm or more, the handling property after forming the phosphor layer is improved. Moreover, by making the thickness of the support 750 μm or less, functional layers such as a reflective layer, a conductive layer, and an easy-adhesion layer can be easily processed by roll-to-roll, and productivity is improved. From the viewpoint of improvement, it is very useful.

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 / visible light and emits it.

  For the phosphor used in the present invention, various conventionally known phosphor matrix compounds, and various compounds obtained by doping these phosphor matrix compounds with conventionally known appropriate activators may be used. it can.

  For example, those containing alkali metal halides, alkaline earth metal halides, and rare earth element halides as phosphor matrix compounds. Here, among the halides of alkaline earth metals, fluorides are generally insoluble in water, while other halides are highly water-soluble and tend to cause deliquescence problems. . Accordingly, examples of the alkaline earth metal halide include halides other than fluoride.

  The halogen constituting these halides is not particularly limited as long as it provides a deliquescent halide capable of forming a columnar crystal and functioning as a phosphor, and 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, the halogen constituting these halides is preferably bromine and iodine, and iodine is particularly preferred.

  Examples of the alkali metal include lithium, sodium, potassium, rubidium, and cesium. Preferred examples of these include sodium and cesium, and cesium is particularly preferable.

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

Examples of rare earth elements include scandium, yttrium, and various lanthanoid elements, and suitable examples of these include lanthanum and cerium.
An example of a suitable phosphor includes a phosphor having a cubic crystal structure and containing an alkali metal halide as the phosphor matrix compound.
These compounds may be used alone or in combination of two or more.

  In the present invention, the expression “phosphor containing X as a base material” is sometimes used, and this includes X as a phosphor base material compound regardless of whether the activator is doped. The phosphor may be composed only of X, or may be doped with an activator for X (ie, containing X and an activator) ).

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

Further, as other suitable phosphor matrix compounds that can constitute the phosphor, alkaline earth metal halides such as calcium halide, strontium halide, cesium barium iodide (CsBa ₂ I ₅ ), cerium bromide, odor Also included are lanthanide halides such as lanthanum halides. Here, examples of the strontium halide include strontium iodide and strontium bromide, and examples of the calcium halide include calcium iodide and calcium bromide.

Here, in the present invention, it does not preclude the use of the above phosphor base material compound such as CsI as the phosphor constituting the scintillator layer 12 as it is. However, from the viewpoint of sufficiently ensuring the luminous efficiency, it is preferable to use as the phosphor 120 a phosphor obtained by doping a phosphor base material compound with various activators. Suitable examples of such activators include activators such as thallium (Tl), europium (Eu), indium (In), lithium (Li), potassium (K), rubidium (Rb), and sodium (Na). It is preferable to contain at least one of these. In the present invention, a phosphor obtained by using an additive containing a thallium compound and cesium iodide as raw materials, that is, a 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 broad emission wavelength from 400 nm to 750 nm and can be detected by a general-purpose light detection panel.
Here, in this invention, 0.1-3 mol% is preferable for the relative content of the activator in the part which functions as a fluorescent substance layer which contributes to fluorescence emission among the scintillator layers 12.

  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 certain plane index of the phosphor columnar crystals. The orientation degree based on the X-ray diffraction spectrum of the surface having s is in the range of 80 to 100% regardless of the position in the layer thickness direction of the scintillator layer from the base close to the phosphor columnar crystal substrate.

In the present invention, the degree of orientation is more preferably in the range of 95 to 100%. The constant surface index may be any one of (100), (110), (111), (200), (211), (220), (311), etc. (Refer to pages 42 to 46 for an introduction to the X-ray analysis (Tokyo Kagaku Dojin) for the surface index). Thereby, an independent columnar shape is obtained even on the substrate side of the columnar crystal, scattering of light components generated in the phosphor is suppressed, and the light is efficiently emitted toward the photoelectric conversion element. Combining with FOP is more effective because it propagates to FOP single fiber without optical loss. In the present invention, the “degree of orientation based on the X-ray diffraction spectrum of a surface having a constant surface index” means the ratio of the intensity Ix of a certain surface index to the total intensity I including the surface of other surface index. Refers to that. For example, the orientation of the intensity I ₂₀₀ of (200) plane in X-ray diffraction spectrum is a "degree of orientation = I ₂₀₀ / I". As a method for measuring the plane index for determining the degree of orientation, for example, X-ray diffraction (XRD) can be mentioned. X-ray diffraction can illuminate a crystalline material with specific X-rays of a specific wavelength, and use the fact that diffraction that satisfies the Bragg equation occurs to obtain knowledge about the material identification, crystal phase structure, etc. It is a highly versatile analytical method. The target of the irradiation system is Cu, Fe, Co or the like and depends on the apparatus capability, but generally the output upon irradiation is about 0 to 50 mA and about 0 to 50 kV.

  Further, in the present invention, the phosphor constituting the scintillator layer 12 has a columnar crystal shape in which scattering of emitted light within the crystal is suppressed by the light guide effect. As a method for forming the columnar crystal, a vapor deposition method may be mentioned. As the vapor deposition method, a vapor deposition method, a sputtering method, a CVD method, an ion plating method, or the like can be used. In the present invention, the vapor deposition method is particularly preferable.

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

  However, in the present invention, as a suitable scintillator layer 12, a scintillator layer composed only of a phosphor layer composed of a phosphor matrix compound and an activator, and a phosphor layer composed of a phosphor matrix compound and an activator, And a scintillator layer including a base layer composed of a phosphor matrix compound and an activator. Among these, a phosphor layer composed of a phosphor matrix compound and an activator, a phosphor matrix compound and an activator Particularly preferred is a scintillator layer including 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 composed of a phosphor matrix compound and an activator. In between, it is preferable that the base layer which consists of a fluorescent substance base material compound and an activator and whose porosity is larger than a fluorescent substance layer is provided.

  The relative content of the activator in the underlayer is preferably from 0.01 to 1 mol%, more preferably from 0.1 to 0.7 mol%. In particular, the relative content of the activator in the underlayer is preferably 0.01 mol% or more from the viewpoint of improving the light emission luminance and storage stability of the scintillator panel 10. Further, 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 content of the relative activator in the underlayer relative to the relative content of the activator in the phosphor layer. The ratio ((relative content of activator in the underlayer) / (relative content in the phosphor layer)) is preferably 0.1 to 0.7.

  As a method for forming the phosphor columnar crystal, in order to satisfy the requirements for the plane index, a step of forming a base layer having a lower porosity than the phosphor layer on the surface of the substrate, and a surface of the base layer It is preferable that the manufacturing method includes an embodiment including a step of forming a phosphor by vapor deposition. The porosity in this patent refers to the ratio of the area of the void to the sum of the cross-sectional area of the columnar crystals and the area of the void in the cross section obtained by cutting the phosphor layer in parallel with the support. The porosity is obtained by excising the phosphor layer of the scintillator panel in parallel with the support and binarizing the cross-sectional scanning electron micrograph of the phosphor portion and the void portion using image processing software. be able to. In addition, it is preferable that the thickness of a fluorescent substance layer (phosphor layer) is 100-800 micrometers, and it is more preferable that it is 120-700 micrometers from the point from which the characteristic of a brightness | luminance and sharpness is acquired with sufficient balance. The layer thickness of the underlayer is preferably 0.1 μm to 50 μm, more preferably 5 μm to 40 μm from the viewpoint of maintaining high brightness and sharpness.

Adhesion layer 16
An adhesion layer is formed between the support and the phosphor layer. As the adhesion layer, a layer 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 (nitrocellulose, etc.), styrene-butadiene copolymer, various synthetic rubber resins, phenol resin, epoxy resin, urea resin, melamine resin, phenoxy resin, silicone Examples thereof include resins, acrylic resins, urea formamide resins, and the like. Among these, it is preferable to use polyurethane, polyester, silicone resin, fluororesin, acrylic resin, or polyvinyl butyral. Moreover, these 2 or more types can also be mixed and used.

Examples of the metal oxide constituting the adhesion layer include SiO ₂ and TiO ₂ . When forming a metal oxide layer, you may comprise from several oxide layers.
The metal material constituting the adhesion layer preferably contains a metal material such as aluminum, silver, platinum, palladium, gold, copper, iron, nickel, chromium, cobalt, and stainless steel. Among these, it is particularly preferable that aluminum or silver is the main component from the viewpoint of reflectance and corrosion resistance. Two or more kinds of such metal materials may be used.

  In the present invention, the adhesive layer is preferably one in which a filler is dispersed in a binder made of the resin material. The particle size and blending amount of the filler are appropriately selected in consideration of the thickness of the adhesion layer to be formed and the optical characteristics.

As the filler, a known inorganic powder or organic powder 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 meteorite, garnet, mica, silica, silicon nitride, 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 Ba, Sr and Ca atoms, and X is a Cl atom or a Br atom.), CaCO ₃ , ZnO, Sb ₂ O ₃ , ZrO ₂ Lithopone (BaSO ₄ · ZnS), magnesium silicate, basic lead silicate sulfate, basic lead phosphate, aluminum silicate, and the like can be used. Examples of organic powders include carbon black and pigments in addition to powders such as three-dimensionally crosslinked polymethyl methacrylate, polystyrene, and Teflon (registered trademark). These powders may be surface-treated.

  The adhesion layer preferably has a function of absorbing or reflecting electromagnetic waves, and in the case of reflection, light scattering particles and in the case of absorption, light absorption particles are preferably dispersed in a resin binder as fillers. (Such an adhesion layer is called a coating-type adhesion layer). As described above, the adhesion layer having a function of absorbing or reflecting electromagnetic waves is for absorbing or reflecting electromagnetic waves emitted from the phosphors and increasing light extraction efficiency. Thereby, the scintillator excellent in high-intensity and sharpness can be comprised.

  The light scattering particles have a function of improving sharpness by preventing light diffusion of emitted 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 adhesion layer. Examples of the material include 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) And 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 a strong hiding power and a high refractive index, the light emitted from the scintillator can be easily scattered by reflecting and refracting the light, and the sensitivity of the resulting panel can be significantly improved.

  As other light scattering particles, for example, glass beads, resin beads, hollow particles having hollow portions in the particles, multi-hollow particles having many hollow portions in the particles, porous particles, etc. may be used. Can do.

The 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); LaSFN9 (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 higher). . Examples of the resin beads include acrylic particles, polyester resin particles, polyolefin particles, and silicon particles. Specifically, Chemisnow (registered trademark) (manufactured by Soken Chemical Co., Ltd.), silicon resin KR series and others (manufactured by Shin-Etsu Chemical Co., Ltd.) Techpolymer (registered trademark) (manufactured by Sekisui Plastics Kogyo Co., Ltd.) can be suitably used.

  In particular, white pigments such as titanium oxide have high concealability and a high refractive index, so that the light emitted from the scintillator can be easily scattered by reflecting and refracting light, and the sensitivity of the scintillator panel can be significantly improved. . As the white pigment, those described above can be used and are not limited to these, but among these, titanium oxide is preferable.

As the crystal structure of titanium oxide, either a rutile type or an anatase type can be used, but a rutile type is preferable because it has a large ratio to the refractive index of the resin and can achieve high luminance.
Specific examples of such titanium oxide particles include CR-50, CR-50-2, CR-57, CR-80, CR-90, CR-93, and CR-95 manufactured by the 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 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 (Product name: Ishihara Sangyo Co., Ltd.)

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

  The light absorbing particles are used for easily adjusting the reflectance of the support with a desired value with high accuracy. Examples of the light absorbing particles include light absorbing pigments. Various conventionally known pigments can be used as the light absorbing pigment. Specifically, ultramarine blue, prussian blue (iron ferrocyanide), phthalocyanine, anthraquinone, indigoid, carbonium, titanium black, carbon black and the like can be used.

The adhesion layer may contain both the light scattering particles and the light absorption particles.
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. Although there is no restriction | limiting in particular about an application | coating system, For example, general systems, such as a gravure, die | dye, comma, bar, dip, spray, spin, can be used.

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

  Moreover, you may use a dispersing agent as needed, for example, a polyhydric alcohol, amines, silicone, or surfactant can be used. It is preferable that 40-95 mass% of light-scattering particles are contained in the contact | adherence layer, and it is especially preferable that 60-90 mass% is contained. When the amount is 40% by mass or more, the luminance is improved, and when the amount is 95% by mass or less, the adhesion to the support or the phosphor is improved.

  A dispersant may be used to improve the dispersibility of titanium oxide or 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, and more preferably 1 μm or more and 60 μm or less when made of 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 viewpoints of luminance improvement and light extraction efficiency.

  The film thickness of the coating-type adhesion layer is preferably 10 to 500 μm. Sufficient luminance is obtained when the thickness of the adhesive layer is 10 μm or more, and smoothness is improved when the thickness is 500 μm or less. When titanium oxide is included, it is preferably contained in the coating-type adhesion layer in an amount of 40 to 95% by mass, particularly preferably 60 to 90% by mass. When the amount is 40% by mass or more, the luminance is improved, and when the amount is 95% by mass or less, the adhesion to the support or the phosphor is improved.

  The formation method of a metal oxide layer can also be based on a well-known method. However, in a typical embodiment of the present invention, a vapor deposition method is generally used because a layered dense adhesion layer is easily formed. As the vapor deposition method, known methods such as vapor deposition, sputtering, ion plating, and plasma CVD can be used, but sputtering and plasma CVD capable of forming 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 foil, but sputtering is preferable from the viewpoint of adhesion.
The support on which the adhesion layer and the like are 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 A manufacturing method in which the phosphor layer is formed by a vapor deposition method including a step of vapor-depositing the phosphor material while rotating is preferable.

<Dampproof protective layer 13>
The moisture-proof protective layer may be formed from a single material, may be formed from 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, when the phosphor is cesium iodide (CsI), CsI absorbs water vapor in the air and is deliquescent if it is exposed to high moisture absorption. For the purpose of preventing, a moisture-proof protective layer is provided. The protective layer also has a function of blocking substances (for example, halogen ions) emitted from the phosphor of the scintillator panel and preventing corrosion on the light receiving element side caused by contact between the scintillator layer and the light receiving element.

  Further, in the aspect in which the scintillator panel formed from the columnar phosphor crystal of the scintillator panel and the photoelectric light receiving element are bonded with, for example, an adhesive or optical oil, the protective layer is formed of the columnar phosphor. It also plays a role of a penetration preventing layer that prevents penetration between crystals.

  This protective layer can be formed using various materials. In the present invention, the protective layer may be made of polyolefin, polyacetal, epoxy, polyimide, silicone, or polyparaxylylene. The polyparaxylylene system can be formed by a CVD method and has a feature of low water vapor and gas permeability, and is suitable for a protective layer of CsI: Tl that is originally deliquescent. Here, polyparaxylylene is polyparaxylylene, polymonochloroparaxylylene, polymonochloroparaxylylene, polydichloroparaxylylene, polytetrachloroparaxylylene, polyfluoroparaxylylene, polytetrachloroparaxylylene. , Polyfluoroparaxylylene, polydimethylparaxylylene, polydiethylparaxylylene and the like.

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

<Rough absorption layer 17>
As shown in FIG. 1, a undulation absorbing layer 17 may be provided between the scintillator layer 12 and the FOP 11 in order to absorb surface undulations.
As the undulation absorbing layer, a resin transparent to visible light is used. In the present invention, as such a resin, a hot melt having the property that it has adhesiveness to other organic materials and inorganic materials in a heated and melted state, has no adhesiveness in a solid state at room temperature, and does not contain a solvent / solvent. It is preferable to use a resin. As the hot melt resin, those mainly composed of polyolefin, polyester, polyamide, etc. are preferable. 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 transmittance. . Thus, it is preferable that the relief absorbing layer using the hot melt resin is a single layer over the entire surface of the scintillator layer and the FOP in the plane direction. By using a single layer in this way, there is no interface when visible light is transmitted, and unwanted light refraction and scattering are minimized.

The thickness of the relief absorbing layer is preferably 30 μm or less. If it is in this range, the surface undulations can be sufficiently absorbed, and the light extraction property is not affected.
By providing an optical compensation layer between the scintillator layer and the relief absorbing layer, the difference in refractive index at the boundary surface may be reduced to further reduce the amount of light reflected at the boundary surface. .

  When the scintillator is irradiated with radiation, the scintillator phosphor converts the radiation into light and emits light. And light propagates in the direction of the relief absorption layer and FOP in the columnar crystal of the phosphor. The light propagating through the phosphor reaches the substantially conical wall surface at the tip 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. Therefore, the amount of light reflected at the boundary surface can be further reduced.

  The optical compensation layer is preferably formed of a thermosetting resin that is cured by applying heat. As the thermosetting resin, an acrylic resin, an epoxy resin, a silicone resin, or the like is preferably used. Further, the optical compensation layer can be formed of a transparent liquid or a gel substance instead of being formed of a solid such as a cured resin. Furthermore, it is also desirable that the optical compensation layer is formed using an adhesive. As the adhesive, for example, a room temperature curable adhesive such as acrylic, epoxy, or silicone can be used. In particular, as an adhesive resin having elasticity, a rubber adhesive can be used. As the resin for the rubber adhesive, a block copolymer such as styrene-isoprene-styrene, a synthetic rubber adhesive such as polybutadiene or polybutylene, natural rubber, or the like can be used. As an example of a commercially available rubber-based adhesive, a one-component RTV rubber KE420 (manufactured by Shin-Etsu Chemical Co., Ltd.) or the like is preferably used.

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

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

The adhesion layer can be formed by the method described in the above item “Adhesion layer”.
In the present invention, the phosphor is preferably formed by a vapor phase method, and specifically, preferably formed by a vapor deposition method.

Formation of the scintillator layer The scintillator layer is formed by using a vapor deposition apparatus having an evaporation source and a substrate rotation mechanism in a vacuum vessel, and placing a support on the support rotation mechanism and rotating the support while rotating the phosphor material. A production method in which the phosphor layer is formed by a vapor deposition method including a step of vapor deposition is preferable.
Hereinafter, an embodiment of the present invention will be described with reference to FIG.

  Near the bottom surface inside the vacuum vessel 32, evaporation sources 38 a and 38 b are arranged at positions facing each other 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, and 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 manufacturing apparatus, it is possible to provide three or more (8, 16, 24, etc.) evaporation sources, and the evaporation sources may be arranged at equal intervals. You may change and arrange. Further, the radius of a circle centered on the center line perpendicular to the support 34 can be arbitrarily determined.

  The evaporation sources 38a and 38b contain the phosphor and heat it by a resistance heating method. Therefore, the evaporation sources 38a and 38b may be composed of an alumina crucible wound with a heater, or a boat or a heater made of a refractory metal. May be. Further, the method of heating the phosphor may be a method such as heating by an electron beam or heating by high frequency induction other than the resistance heating method, but in the present invention, it is relatively easy to handle, inexpensive, and In view of the fact that it can be applied to a large number of substances, a method in which a direct current is passed and resistance heating is performed, and a method in which a crucible is indirectly resistance heated with a surrounding heater is preferable. The evaporation sources 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 improved. It can be made uniform. At this time, as the number of evaporation sources is increased, the vapor flow is rectified at more locations, so that the crystallinity of the phosphor can be made uniform in a wider range. Further, by arranging the evaporation sources 38a and 38b on the circumference of a circle centering on the center line perpendicular to the support 34, the support 34 has the effect that the crystallinity becomes uniform due to the rectification of the vapor flow. Can be obtained isotropically on the surface.

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

  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 enhanced and the quality of the phosphor layer is adjusted. Further, the adsorbate on the surface of the support 34 is removed and removed, and an impurity layer is prevented from being generated between the surface of the support 34 and the phosphor.

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

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

  Further, the support holder 35 is provided with a support rotating mechanism 36 that rotates the support 34 in the horizontal direction. The support rotating mechanism 36 supports the support holder 35 and rotates a support 34 and a motor (not shown) that is disposed outside the vacuum vessel 32 and serves as a drive source for the support rotating shaft 37. Z).

  In addition to the above configuration, the vapor deposition apparatus is provided with a vacuum pump in a vacuum vessel. The vacuum pump exhausts the gas existing in the vacuum vessel. In order to exhaust to the high vacuum region, two or more types of vacuum pumps having different operating pressure regions may be arranged. As the 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 gas into the vacuum vessel is provided. As the gas to be introduced, an inert gas such as Ne, Ar, or Kr is generally used. 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 evacuating until the vacuum is higher than the desired pressure, the evacuation is stopped. Then, the gas may be adjusted by introducing gas until a desired pressure is reached. Further, the pressure in the vacuum container may be controlled by adjusting the pump displacement by providing a pressure control valve between the vacuum container and the vacuum pump.

  Further, a shutter 39 for blocking the space from the evaporation sources 38a and 38b to the support 34 is provided between the evaporation sources 38a and 38b and the support 34 so as to be openable and closable in the horizontal direction. In the evaporation sources 38a and 38b, substances other than the target substance attached to the surface of the phosphor can be prevented from evaporating in the initial stage of vapor deposition and adhering to the support 34.

The manufacturing method of the scintillator panel of the present invention using the manufacturing apparatus 31 will be further described.
First, the support 34 is attached to the support holder 35. Further, in the vicinity of the bottom surface of the vacuum vessel 32, evaporation sources 38 a and 38 b are arranged on the circumference of a circle centering on a center line perpendicular to the support 34. Next, a crucible, a boat, or the like is filled with two or more phosphor base compounds (CsI: no activator) and an activator (TlI) and set in an evaporation source.

  In order to remove impurities in the filled phosphor base material and activator before vapor deposition, preheating may be performed. It is desirable that the preheating is below the melting point of the material used. For example, in the case of CsI, the preheating temperature is preferably 50 to 550 ° C, more preferably 100 to 500 ° C. 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, more preferably 4 to 10 revolutions / minute, although it depends on the size of the apparatus. Next, the crucible of the phosphor matrix compound (CsI: no activator) is heated to deposit the phosphor, thereby forming an underlayer (first phosphor layer). At this time, the substrate temperature is preferably 5 to 100 ° C, more preferably 15 to 50 ° C. The thickness of the underlayer is preferably 0.1 to 50 μm, although it depends on the crystal diameter and the thickness of the phosphor layer. Next, heating of the substrate is started, the substrate temperature is heated to 150 to 250 ° C., and evaporation of the remaining phosphor base compound (CsI: no activator) and activator (TlI) crucible is started. At this time, it is preferable that the phosphor base compound evaporates at a higher deposition rate than the underlayer in consideration of productivity. Although it depends on the thickness of the underlayer and the phosphor layer, it is preferably deposited at a rate of 5 to 100 times, more preferably 10 to 50 times that at the time of depositing the underlayer. The activator evaporation method may evaporate the activator alone, but an evaporation source in which CsI and TlI are mixed is prepared and heated to a temperature at which only TlI evaporates without CsI evaporating (for example, 500 ° C.). It may be evaporated.

Since the support that has been heated at the time of vapor deposition has a high temperature, it needs to be cooled to be taken out. By setting the average cooling rate in the step of cooling the phosphor layer to 80 ° C. within 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 the support. This cooling step is particularly preferably performed in an atmosphere having a degree of vacuum of 1 × 10 ⁻⁵ Pa to 0.1 Pa. In addition, a means for introducing an inert gas such as Ar or He into the vacuum container of the vapor deposition apparatus may be provided during the cooling process. The average cooling rate here is a value obtained by continuously measuring the time and temperature during cooling from the start of cooling (at the end of vapor deposition) to 80 ° C. and determining the cooling rate per minute during this time. .

After the vapor deposition, the phosphor layer may be heat treated. In the vapor deposition method, reactive vapor deposition may be performed in which vapor deposition is performed by introducing a gas such as O ₂ or H ₂ as necessary.
In the present invention, the support on which the phosphor layer is formed preferably has the same dimensions as the support, the adhesion layer, and the phosphor layer. For this reason, in the manufacture of a scintillator panel, a support on which a phosphor layer is formed is cut into a product size together with the support after forming a phosphor layer larger than the product size on a support larger than the product size. It is preferable. Productivity can be improved by cutting out each of the plurality of supports with a phosphor layer 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, laser light, and the like.

In order to laminate the adhesive scintillator layer with FOP and FOP, for example, they are laminated through a relief absorbing layer. As a relief absorbing layer, a sheet made of hot melt resin is sandwiched between the phosphor layer and the FOP and heated in a pressurized state to fix the phosphor layer surface while absorbing minute relief. is there.

The hot melt resin sheet used as the undulation absorbing layer has a structure in which a protective layer that can be peeled is disposed on both sides of the hot melt resin sheet. Is achieved.
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, the phosphor layer and the FOP are laminated by first cutting the hot melt resin sheet into the same shape as the FOP, peeling off the protective layer on the FOP side, and then peeling off the protective layer of the hot melt resin sheet. Laminate the surface and FOP, perform temporary fixing (temporary bonding) in the temperature range of 60 ° C to 80 ° C under pressure equivalent to atmospheric pressure, and then peel off the protective layer on the phosphor layer side of the hot melt resin sheet Then, the hot melt resin sheet and the phosphor layer of the scintillator are laminated, and permanent fixing (main bonding) is performed in a temperature range of 80 ° C. to 100 ° C. under a pressure corresponding to atmospheric pressure.

  The laminated body in which the temporarily fixed hot melt resin sheet and the FOP, and the permanently fixed FOP / hot melt resin sheet and the phosphor layer are laminated at the time of fixing are sealed in a bag-like thermocompression-bondable thermocompression film bag. Then, under vacuum, the bag is thermocompression-bonded to seal the laminate, and then the laminate is taken out of the bag and heated to a predetermined temperature range in a pressure contact state under atmospheric pressure to be temporarily fixed and permanently fixed. Is done.

  Moreover, as shown in the lower part of FIG. 3, the hot melt resin sheet from which the protective layer has been peeled is temporarily fixed to the phosphor layer of the scintillator before cutting in a temperature range of 60 ° C. to 80 ° C. under a pressure equivalent to atmospheric pressure ( Temporary bonding) to obtain a phosphor / hot melt resin laminate. After this is made into a phosphor / hot melt resin laminate having 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), and placed on the FOP and laminated, and the atmospheric pressure You may implement this fixing (main bonding) in the temperature range of 80 to 100 degreeC under considerable pressurization. Also in this case, the thermocompression film bag is used as described above at the time of fixing.

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

  In this recess, an FOP having a scintillator layer bonded to the upper surface is placed, and a moisture-proof protective layer is deposited by a CVD method, whereby a moisture-proof layer is formed on the surface and side surfaces of the scintillator layer and part of the FOP side surfaces. In the CVD method, not all the inside of the gap is uniformly deposited, but is deposited so as to gradually become thinner. For this reason, the lower end of the FOP side surface is not deposited, and a moisture-proof layer having a predetermined inclination is formed. The thickness of this lower end corresponds to T2 shown in FIG. An inclination transition part is a side surface which transfers from a scintillator to FOP, and an inclination may start in the middle of the side surface of FOP.

The inclination of the moisture-proof protective layer can be adjusted by the width and depth of the gap around the FOP.
After forming the moisture-proof layer, it may be processed by polishing to a predetermined thickness.
In the embodiment of the present invention, since the moisture-proof protective layer has a high binding force with the FOP, the moisture-proof protective layer is not peeled off and the moisture resistance is not impaired.

When chamfering FOP, chamfering may be performed after the moisture-proof protective layer is formed.
FIG. 5 is a schematic cross-sectional view of one embodiment of the apparatus used for forming the protective layer, and is an example in which a protective layer made of polyparaxylylene is formed on the surface of the 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 to radicalize, and scintillator for diparaxylylene in a radicalized state. A vapor deposition chamber 53 for vapor deposition on the upper phosphor layer 122, a cooling chamber 54 for deodorizing and cooling, and an exhaust system 55 having a vacuum pump are provided. Here, the vapor deposition chamber 53 has an inlet 53a for introducing the polyparaxylylene radicalized in the thermal decomposition chamber 52 and an outlet 53b for discharging excess polyparaxylylene, as shown in FIG. It has a turntable (deposition stand) 53c that supports a sample on which polyparaxylylene is deposited.

First, the phosphor layer 122 of the scintillator panel 42 is placed on the turntable 53c of the vapor deposition chamber 53 so as to face upward.
Next, diparaxylylene radicalized by heating to 175 ° C. in the vaporizing chamber 51 and vaporizing by heating to 690 ° C. in the thermal decomposition chamber 52 is introduced into the vapor deposition chamber 53 from the inlet 53a, and the phosphor layer A protective layer (polyparaxylylene) 123 is vapor-deposited on the surface 122 with a thickness of 3 μm. In this case, the inside of the vapor deposition chamber 53 is maintained at a degree of vacuum of 13 Pa. The turntable 53c is rotated at a speed of 4 rpm. Excess polyparaxylylene is discharged from the discharge port 53b and led to a cooling chamber 54 for deodorizing and cooling and an exhaust system 55 having a vacuum pump.

<Application>
The scintillator panel of the present invention can be applied to various types 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 a photodetection panel with the above-mentioned scintillator panel which has a scintillator layer. In such a radiation detector, X-rays from the outside are 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 the position information. State.

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

  Among these, the photoelectric conversion element has a function of absorbing light generated in the scintillator layer and converting it into a charge form. 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 that is excited by incident light to generate charges, and a counter electrode. Any of these transparent electrodes, charge generation layers, and counter electrodes may be conventionally known ones. The photoelectric conversion element used in the present invention may be composed of an appropriate photosensor. For example, the photoelectric conversion element may be a two-dimensional arrangement of a plurality of photodiodes, or a CCD ( A two-dimensional photosensor such as a charge coupled device (CMOS) or a complementary metal-oxide-semiconductor (CMOS) sensor may be used.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.
<Example 1>
A 125 μm thick polyimide film is used as the base material, and the surface on which the phosphor is formed as the adhesion layer is coated with a crystalline polyester Byron resin (Toyobo Co., Ltd.) to a thickness of 3 μm. After the Byron resin is aged, it is cut. Thus, a support for vapor deposition was obtained. A 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 the FOP, and then a hot melt sheet 30 μm thick and the scintillator were laminated on the 3 mm thick FOP in the following two steps.
First, a laminate (laminated body A) obtained by laminating the above FOP and hot melt sheet is encapsulated in a bag made of a thermocompressible film sheet, and the film sheet is thermocompressed under vacuum to form a laminated body A. Was sealed. After returning the sealed film sheet bag to atmospheric pressure, the laminate A is taken out and heated at 60 ° C. for 1 hour while applying pressure by atmospheric pressure, so that the hot melt sheet melts and FOP and hot melt are melted. The sheet was temporarily fixed.

  Next, the scintillator phosphor surface (light emitting surface) placed in the FOP / hot melt sheet laminate (laminate B) with the orientation facing the hot melt sheet is put into a bag made of a thermo-compressible film sheet. After encapsulating, FOP and scintillator were laminated by heating at 80 ° C. for 1 hour under pressure and adhesion in the same manner as described above.

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

  In this example, the shape of the jig used when forming the moisture-proof protective layer made of polyparaxylylene is a hole structure having a gap in the range of 10 to 100 μm from the scintillator panel, so that the moisture-proof protective layer on the side surface of the FOP The thickness was adjusted so as to be thin in the vicinity of the lower end. The lower end of the moisture-proof protective layer made of polyparaxylylene was at a position 0.5 mm from the visible light exit surface of the FOP.

  In the obtained scintillator panel, when the distance covered by the moisture-proof protective layer on the side surface of the scintillator is A and the distance covered by the moisture-proof protective layer in the thickness direction of the FOP is B, A is 0.6 mm, and B is 3.0 mm. Met. Further, 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, T1 is 10 μm and T2 is 0.5 μm. Met.

When the scintillator panel on which the moisture-proof protective layer made of polyparaxylylene was formed in this way was placed on a reading sensor having a CMOS element and the sharpness was measured, the case where FOP was not bonded at each spatial frequency It was found that the sharpness was improved to 110% with respect to the scintillator. The brightness was 70% compared to a scintillator without FOP bonding. Further, when the moisture resistance test was performed in an environment of 40 ° C. and 70% RH, the sharpness after 196 hours did not vary.
The evaluation in the examples was performed as follows.

Evaluation method of scintillator panel sharpness Using an X-ray irradiation device 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 a sharpness index. MTF is an abbreviation for Modulation Transfer Function. At this time, 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 defined as 100.

Evaluation method of scintillator panel sensitivity (luminance) The scintillator panel sensitivity (luminance) evaluation method uses an X-ray irradiation apparatus with a tube voltage set to 80 Kvp, and X-rays are emitted from an FPD equipped with a radiation image detector. An average signal value of the entire surface of the X-ray image is obtained from the X-ray image data obtained by irradiating the light receiving surface, and is used as the sensitivity of the scintillator panel. At this time, the average signal value of the radiation image detector equipped with the scintillator panel produced in the same manner as in Example 1 except that FOP is not bonded is set to 100.

Moisture resistance test A moisture resistance test is performed in an environment of 40 ° C. and 70% RH, and the sharpness after 196 hours is evaluated.

<Example 2>
When making the scintillator, the adhesion layer was formed by using a byron resin containing 40% by mass of titanium oxide as a white pigment in the adhesion layer, and the phosphor layer was produced in the same manner as in Example 1. After that, FOP was bonded through hot melt to produce a scintillator panel, and then a moisture-proof protective film was formed. The scintillator panel obtained was evaluated in the same manner as in Example 1. As a result, the sharpness decreased by 30% as compared with the scintillator without FOP bonding as in Example 1, but the brightness became 130% of the scintillator without FOP bonding, and a high-luminance scintillator was obtained. Further, the sharpness by the moisture resistance test was not changed.

<Example 3>
When creating the scintillator, an adhesion layer using a Byron resin containing 40% by mass of carbon black as a black pigment was formed 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, and a moisture-proof protective film was formed to produce a scintillator panel. As a result of evaluating the optical characteristics of the obtained scintillator panel in the same manner as in Example 1, the sharpness was improved by 20% compared with the scintillator without FOP bonding, and the luminance was 60% compared with the scintillator without FOP bonding. However, a highly sharp scintillator was obtained. Further, the sharpness by the moisture resistance test was not changed.

<Comparative Example 1>
A laminated body of scintillator and FOP was prepared in the same manner as in Example 1, and instead of the jig used in the Example, the entire laminated body was put on a smooth carbon plate and put into a CVD apparatus. A moisture-proof protective layer made of polyparaxylylene was formed under the same conditions as in 1.

  Since the moisture-proof protective layer made of polyparaxylylene coats the scintillator / FOP bonded body and the carbon plate as a unit, separation from the carbon plate was performed by separating the interface portion 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 moisture-proof protective layer at the bottom of the FOP is not cut by a cutter. It became a rule and a variation of 10-15 μm was observed.

  Such a scintillator had the same initial performance as 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 laminated body of scintillator and FOP was prepared in the same manner as in Example 1, and a polyparaffin was formed by CVD in a form in which needle-like protrusions were held side by side so as to support the radiation incident surface of the scintillator with dots. A moisture-proof protective layer made of xylylene was formed.

  In the scintillator thus prepared, a moisture-proof protective layer made of polyparaxylylene having a thickness of 10 μm was also formed on the exit surface of the FOP. In this state, the same optical characteristics as in Example 1 were examined. The brightness and moisture resistance were not particularly changed, but the sharpness was deteriorated.

10 Scintillator panel 11 Fiber optics plate (FOP)
12 scintillator layer 13 moisture-proof protective layer 14 support 15 phosphor 16 adhesion layer 17 undulation absorption layer

Claims (15)

  A radiation optics plane (FOP); a scintillator for converting radiation provided on the light incidence plane on the FOP to visible light; and the FOP provided on the scintillator. A scintillator panel comprising a moisture-proof protective layer disposed so as to cover at least a part of the scintillator panel, wherein the moisture-proof protective layer is not disposed on the light exit surface of the FOP.   The scintillator panel according to claim 1, wherein the moisture-proof protective layer continuously covers the scintillator surface and the entire side surface and at least a part of the side surface of the FOP.   2. The relationship of A ≦ B is satisfied, where A is the distance covered by the moisture-proof protective layer on the side surface of the scintillator and B is the distance covered by the moisture-proof protective layer in the thickness direction of the FOP. The scintillator panel according to 2 or 2.   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 is T1> T2. The scintillator panel according to any one of claims 1 to 3.   The scintillator includes 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 arrangement surface of the support. The scintillator panel according to any one of claims 1 to 4, wherein the scintillator panel is characterized by the above.   The scintillator panel according to claim 1, wherein the moisture-proof protective layer is made of a paraxylylene polymer.   The scintillator panel according to any one of claims 1 to 6, wherein the scintillator and the FOP are in contact with each other through a relief absorbing layer.   The scintillator panel according to claim 7, wherein the undulation absorbing layer is a layer made of a hot-melt resin that is transparent to visible light.   The scintillator panel according to any one of claims 7 to 8, wherein the undulation absorbing layer has a thickness of 30 µm or less.   The scintillator panel according to any one of claims 7 to 9, wherein the undulating absorption layer is a single layer over the entire surface in the panel plane direction.   6. The scintillator panel according to claim 5, wherein the support, the adhesion layer, and the phosphor layer have the same dimensions in a planar direction.   The scintillator panel according to claim 5, wherein the adhesion layer is made of a combination of at least one of resin, metal oxide, and metal.   The scintillator panel according to claim 5, wherein the adhesion layer has a function of absorbing or reflecting electromagnetic waves generated in the phosphor layer.   The scintillator panel according to any one of claims 1 to 13, wherein a chamfering process is performed on at least an outer peripheral portion of the emission surface of the FOP.   A radiation detector comprising the scintillator panel according to claim 1.

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