JP5597930B2 - Radiation image detection apparatus and manufacturing method thereof - Google Patents

Description

  The present invention relates to a radiological image detection apparatus capable of obtaining a uniform image without causing defects such as unevenness in the radiographic image, and a manufacturing method thereof.

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

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

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

  By the way, especially as a medical device, a radiation detector corresponding to a large area is necessary. For example, a chest X-ray transmission device requires a large area of 46 cm square. Therefore, development of a radiation image detection apparatus that is compact in size and capable of moving images while detecting radiation of a large area is in progress. For example, if a highly sensitive photoelectric conversion element of hydrogenated amorphous silicon is used as the photoelectric conversion element, the area can be easily increased. Moreover, if this element is combined with a phosphor, large area radiation can be directly detected with high sensitivity without using a reduction optical system or image intensifier, etc. An image detection apparatus can be realized. For example, it is conceivable to combine a two-dimensional photoelectric conversion device and a phosphor.

  In this large-area radiation image detection apparatus, a phosphor sheet provided with a phosphor and a substrate having a photoelectric conversion element are often adhered to the entire surface with an adhesive according to a conventional method.

  With the increase in area of the radiation image detection device and the integration of the phosphor and the photoelectric conversion element, several problems have arisen. The difference in thermal expansion coefficient between the glass substrate and the phosphor sheet or adhesive is not negligible, and the problem arises that the phosphor sheet is cracked or the substrate is bent.

  It is difficult to form a uniform adhesive layer on the entire surface of the substrate, it is difficult to keep the flatness of the phosphor sheet uniform, and impurities in the adhesive adversely affect the phosphor and the underlying device. there were. Therefore, a protective film must be further added, resulting in a further addition between the phosphor sheet and the substrate.

  The base sheet must have a thickness close to 1 mm in order to provide moderate strength and uniform flatness. In general, aluminum that has a high X-ray transmittance also serves as a reflector for the light generated in the phosphor. In many cases, a plate is used, so that the mass of the entire radiological image detection apparatus tends to be heavy.

  In addition, there is a problem that a useless gap is generated between the photoelectric conversion element and the phosphor, such as a protective film of the phosphor sheet, an adhesive layer, and the use efficiency of light is reduced, and the image is blurred due to scattering here. there were. Especially for medical devices, there is a demand to reduce the irradiation amount of radiation to the human body as much as possible, and since the conversion efficiency of the phosphor from radiation to light is about several tens of percent, it is desirable to make effective use of light as much as possible. Under these conditions, this reduction in efficiency is a serious problem.

  In addition, the phosphor has a hygroscopic property, and many of the phosphors deteriorate when it absorbs moisture. In many cases, the phosphor has a negative effect on the hygroscopic property of the adhesive.

  That is, as described above, the following problems have arisen with the increase in the area of the radiation image detection apparatus and the integration of the phosphor and the photoelectric conversion element. That is, (i) the phosphor sheet is cracked and the substrate is bent due to the difference in thermal expansion coefficient between the glass substrate and the phosphor sheet or adhesive. (Ii) It is difficult to form a uniform adhesive layer on the entire surface of the substrate, and it is difficult to keep the flatness of the phosphor sheet uniform. (Iii) Impurities in the adhesive adversely affect the phosphor and the underlying device. (Iv) To that end, when a protective film is further added, the result is that an additional layer is added between the phosphor sheet and the substrate. (V) When an aluminum plate is used for the base sheet, the mass of the entire radiation image detection apparatus becomes heavy. (Vi) When the base sheet is completely adhered by the conventional method, a useless gap is generated between the photoelectric conversion element and the phosphor, such as a protective film and an adhesive layer of the phosphor sheet, and light utilization efficiency The image is blurred due to scattering here. (Vii) The phosphor has a hygroscopic property, and many of the phosphors deteriorate when it absorbs moisture, and it has an adverse effect on the device due to the hygroscopic property of the adhesive. (Viii) When an adhesive is applied to the end face of the phosphor sheet, the adhesive adheres to the phosphor and image degradation occurs. (Ix) When atmospheric pressure is applied directly from the back of the sheet, unevenness corresponding to the thickness occurs. (X) An example in which contact is made through glass has been introduced, but unevenness occurs in the case of a rigid object.

  As a solution to the above problem, in a radiation image detection apparatus formed by bonding a substrate having a photoelectric conversion element and a phosphor sheet, the surface of the phosphor sheet and the substrate on which the photoelectric conversion element is formed is lower than atmospheric pressure. A radiological image detection apparatus has been proposed that is held in a state and is in close contact with atmospheric pressure, and at least the phosphor sheet and the end face of the substrate are sealed with a sealing member (Patent Document 1). reference). However, when an adhesive is applied to the end face of the phosphor sheet, the adhesive adheres to the phosphor and image degradation occurs. Further, when the atmospheric pressure is directly applied from the back surface of the sheet, there is a problem that unevenness corresponding to the thickness occurs.

Japanese Patent No. 3880094

  The present invention has been made in view of the above problems and situations, and a solution to the problem is to provide a radiological image detection apparatus capable of obtaining a uniform image without causing defects such as unevenness in the radiographic image, and a method for manufacturing the same. That is.

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

1. A radiological image detection apparatus comprising a scintillator panel having a phosphor layer made of a columnar crystal that converts radiation into light on a photoelectric conversion element array arranged in a two-dimensional manner, on the substrate, the scintillator The panel and the photoelectric conversion element array are in close contact with each other by an atmospheric pressure via a contact support disposed on the substrate side of the scintillator panel, and the contact support is surrounded by a photoelectric conversion element array with an adhesive. A radiographic image detection apparatus, characterized in that the phosphor layer is bonded on the phosphor layer, and the phosphor layer contains a phosphor based on cesium halide (CsX; X is halogen) .

  2. 2. The radiological image detection apparatus according to 1 above, wherein the adhesive and the phosphor layer are not in contact with each other.

  3. 3. The radiological image detection apparatus according to 1 or 2 above, wherein the thermal expansion coefficients of the substrate and the contact support are both 20 ppm / ° C. or less.

  4). 4. The radiographic image detection apparatus according to any one of 1 to 3, wherein a thermal expansion coefficient of the substrate is larger than a thermal expansion coefficient of the support for contact.

  5. 5. The radiological image detection apparatus according to any one of 1 to 4, wherein the moisture permeability of the substrate is larger than the moisture permeability of the support for contact.

  6). 6. The radiological image detection apparatus according to any one of 1 to 5, wherein the substrate is a flexible substrate.

7). 7. The radiation image detection apparatus according to 6 , wherein the flexible substrate is a polymer film substrate containing polyimide.

  8). 8. The radiological image detection apparatus according to any one of 1 to 7, wherein the adhesive is a heat sealing agent or a UV curable resin.

9 . A manufacturing method of a radiological image detection apparatus for manufacturing the radiographic image detection apparatus according to any one of 1 to 8 , wherein the scintillator panel is bonded to the photoelectric conversion element array with a support for adhesion. A method for producing a radiation image detecting apparatus, wherein the photoelectric conversion element array and the support for adhesion are warmed to 20 to 150 ° C. for bonding.

  By the above means of the present invention, it is possible to provide a radiological image detection apparatus and a method for manufacturing the same, which can obtain a uniform image without causing defects such as unevenness in the radiographic image.

The conceptual diagram which shows the state which the scintillator panel and the photoelectric conversion element array are closely_contact | adhered by atmospheric pressure via the support body for contact | adherence Schematic diagram of scintillator panel manufacturing equipment Partially broken perspective view showing schematic configuration of radiographic image detection apparatus

  The radiation image detection apparatus of the present invention is a ray detection apparatus comprising a scintillator panel having a phosphor layer for converting radiation into light on a photoelectric conversion element array arranged two-dimensionally on a substrate, The scintillator panel and the photoelectric conversion element array are in close contact with each other by an atmospheric pressure via a contact support disposed on the substrate side of the scintillator panel, and the periphery of the contact support is photoelectrically converted by an adhesive. It is characterized by being bonded on the element array (see FIG. 1). This feature is a technical feature common to the inventions according to claims 1 to 11.

  As an embodiment of the present invention, it is preferable that the adhesive and the phosphor layer are not in contact with each other from the viewpoint of manifesting the effects of the present invention. Moreover, it is preferable that the thermal expansion coefficients of the substrate and the support for adhesion are both 20 ppm / ° C. or less. Further, it is more preferably 10 ppm / ° C. or less. Furthermore, it is preferable that the thermal expansion coefficient of the substrate is larger than the thermal expansion coefficient of the support for contact. Moreover, it is preferable that the water vapor transmission rate of the said board | substrate is larger than the water vapor transmission rate of the support body for contact | adherence.

  In the present invention, the substrate is preferably a flexible substrate. In this case, the flexible substrate is preferably a polymer film substrate containing polyimide.

  Moreover, in this invention, the said adhesive agent is a heat sealing | fusion sealant or UV curable resin, The radiographic image detection apparatus as described in any one of Claims 1-7 characterized by the above-mentioned.

In the present invention, the phosphor layer preferably contains a phosphor based on cesium halide (CsX; X is halogen). Alternatively, the phosphor layer is preferably a phosphor having gadolinium oxysulfide (Gd ₂ O ₂ S) as a base material.

  As a manufacturing method of the radiation image detection apparatus of the present invention, when the scintillator panel is bonded to the photoelectric conversion element array with the contact support, the temperature of the photoelectric conversion element array and the contact support is warmed to 20 to 100 ° C. It is preferable that it is a manufacturing method of the aspect which adheres.

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

(Configuration of radiation image detector)
The radiological image detection apparatus of the present invention is characterized by including a scintillator panel having a phosphor layer on a substrate for converting radiation into light, but in addition to the phosphor layer, depending on the purpose, it will be described later. It is preferable that the various functional layers are provided.

  The radiological image detection apparatus of the present invention also includes a photosensor on a second substrate on a scintillator panel in which a phosphor layer is provided by a vapor deposition method on a first substrate via a functional layer such as a reflective layer. Radiation by adhering or adhering to a photoelectric conversion panel comprising a photoelectric conversion element section ("planar light receiving element") in which pixels consisting of TFTs (Thin Film Transistors) or CCDs (Charge Coupled Devices) are two-dimensionally arranged. An image conversion panel is preferable.

  Hereinafter, as a typical example, various constituent layers and constituent elements in the case of mainly forming a scintillator panel will be described.

(Configuration of scintillator panel)
The scintillator panel according to the present invention is preferably a scintillator panel in which a phosphor layer made of columnar crystals is provided on a polymer film substrate, and more preferably has an undercoat layer between the substrate and the phosphor layer. Alternatively, a reflective layer may be provided on the substrate, and the reflective layer, the undercoat layer, and the phosphor layer may be configured. Hereinafter, each constituent layer and constituent elements will be described.

(Phosphor layer: scintillator layer)
The phosphor layer according to the present invention is preferably a phosphor layer made of phosphor columnar crystals. Various known phosphor materials can be used as the material for forming the phosphor layer, but the rate of change from X-ray to visible light is relatively high, and the phosphor is easily formed into a columnar crystal structure by vapor deposition. Therefore, the scattering of the emitted light in the crystal can be suppressed by the light guide effect, and the thickness of the phosphor layer can be increased. Therefore, cesium iodide (CsI) and gadolinium oxysulfide (Gd ₂ O ₂ S) is preferred.

However, since CsI or Gd ₂ O ₂ S alone has low luminous efficiency, various activators are added. For example, as shown in Japanese Patent Publication No. 54-35060, a mixture of CsI and sodium iodide (NaI) at an arbitrary molar ratio can be mentioned. Further, for example, CsI as disclosed in Japanese Patent Application Laid-Open No. 2001-59899 is deposited, and thallium (Tl), europium (Eu), indium (In), lithium (Li), potassium (K), rubidium (Rb) ), CsI containing an activating substance such as sodium (Na) is preferred. In the present invention, thallium (Tl) and europium (Eu) are particularly preferable. Furthermore, thallium (Tl) is preferred.

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

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

In the present invention, a preferred thallium compound is thallium bromide (TlBr), thallium chloride (TlCl), thallium fluoride (TlF, TlF ₃ ), or the like.

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

  In the phosphor layer according to the present invention, the content of the additive is desirably an optimal amount according to the target performance, etc., but 0.001 mol% to 50 mol% with respect to the content of cesium iodide, Furthermore, it is preferable that it is 0.1-10.0 mol%.

Here, when the additive is 0.001 mol% or more with respect to cesium iodide, the emission luminance obtained by using cesium iodide alone is improved, which is preferable in terms of obtaining the target emission luminance. Moreover, it is preferable that it is 50 mol% or less because the properties and functions of cesium iodide can be maintained. It is preferable to activate Tb in the Gd ₂ O ₂ S phosphor.

  In addition, it is preferable that the thickness of a scintillator 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.

(Reflective layer)
In the present invention, it is preferable to provide a reflective layer on the polymer substrate, in order to reflect the light emitted from the phosphor (scintillator) and increase the light extraction efficiency. The reflective layer is preferably formed of a material containing any element selected from the element group consisting of Al, Ag, Cr, Cu, Ni, Ti, Mg, Rh, Pt, and Au. In particular, it is preferable to use a metal thin film made of the above elements, for example, an Ag film, an Al film, or the like. Two or more such metal thin films may be formed.

When two or more metal thin films are used, the lower layer is preferably a layer containing Ni, Cr, or both from the viewpoint of improving the adhesion to the substrate. Further, a layer made of a metal oxide such as SiO ₂ or TiO ₂ may be provided in this order on the metal thin film to further improve the reflectance.

  In addition, it is preferable from a viewpoint of emitted light extraction efficiency that the thickness of a reflection layer is 0.005-0.3 micrometer, More preferably, it is 0.01-0.2 micrometer.

(Undercoat layer)
In the present invention, it is preferable to provide an undercoat layer between the substrate and the phosphor layer or between the reflective layer and the phosphor layer from the viewpoint of attaching a film. The undercoat layer preferably contains a polymer binder (binder), a dispersant and the like. The thickness of the undercoat layer is preferably 0.5 to 4 μm, and if it is 4 μm or more, light scattering in the undercoat layer increases and sharpness deteriorates. If the thickness of the undercoat layer is larger than 5 μm, columnar crystallinity is disturbed by the heat treatment. Hereinafter, components of the undercoat layer will be described.

<Polymer binder>
The undercoat layer according to the present invention is preferably formed by applying and drying a polymer binder (hereinafter also referred to as “binder”) dissolved or dispersed in a solvent. Specific examples of the polymer binder include polyurethane, vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer. Polymer, polyamide resin, polyvinyl butyral, polyester, cellulose derivative (nitrocellulose, etc.), styrene-butadiene copolymer, various synthetic rubber resins, phenol resin, epoxy resin, urea resin, melamine resin, phenoxy resin, silicone resin , Acrylic resins, urea formamide resins, and the like. Of these, polyurethane, polyester, vinyl chloride copolymer, polyvinyl butyral, and nitrocellulose are preferably used.

  As the polymer binder according to the present invention, polyurethane, polyester, vinyl chloride copolymer, polyvinyl butyral, nitrocellulose and the like are particularly preferable in terms of close contact with the phosphor layer. Moreover, it is preferable that the glass transition temperature (Tg) is a polymer having a temperature of 30 to 100 ° C. in terms of attaching a film between the deposited crystal and the substrate. From this viewpoint, a polyester resin is particularly preferable.

  Solvents that can be used to prepare the undercoat layer include lower alcohols such as methanol, ethanol, n-propanol and n-butanol, hydrocarbons containing chlorine atoms such as methylene chloride and ethylene chloride, acetone, methyl ethyl ketone, and methyl isobutyl ketone. Such as ketones, toluene, benzene, cyclohexane, cyclohexanone, xylene and other aromatic compounds, methyl acetate, ethyl acetate, butyl acetate and other lower fatty acid and lower alcohol esters, dioxane, ethylene glycol monoethyl ester, ethylene glycol monomethyl ester And ethers thereof and mixtures thereof.

  The undercoat layer according to the present invention may contain a pigment or a dye in order to prevent scattering of light emitted from the phosphor (scintillator) and improve sharpness.

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

  The protective layer can be formed using various materials. For example, a polyparaxylylene film is formed by a CVD method. That is, a polyparaxylylene film can be formed on the entire surface of the phosphor (scintillator) and the substrate to form a protective layer.

  Further, as another protective layer, a polymer film can be provided on the phosphor layer. In addition, as a material of the polymer film, a film similar to the polymer film as a substrate material described later can be used.

  The thickness of the polymer film is preferably 12 μm or more and 120 μm or less, more preferably 20 μm or more and 80 μm or less, taking into consideration the formation of voids, the protective properties of the phosphor layer, sharpness, moisture resistance, workability, etc. Is preferred. The haze ratio is preferably 3% or more and 40% or less, more preferably 3% or more and 10% or less in consideration of sharpness, radiation image unevenness, production stability, workability, and the like. The haze ratio can be measured, for example, by Nippon Denshoku Industries Co., Ltd. NDH5000W. The required haze ratio is appropriately selected from commercially available polymer films and can be easily obtained.

  The light transmittance of the protective film is preferably 70% or more at 550 nm in consideration of photoelectric conversion efficiency, phosphor (scintillator) emission wavelength, etc., but a film having a light transmittance of 99% or more is commercially available. Since it is difficult, substantially 99% to 70% is preferable.

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

(substrate)
The scintillator panel of the present invention preferably uses a polymer film as the substrate. As polymer films, cellulose acetate films, polyester films, polyethylene terephthalate (PEN) films, polyamide films, polyimide (PI) films, triacetate films, polycarbonate films, carbon fiber reinforced resin sheets and other polymer films (plastic films), Those containing a liquid crystal polymer or the like as a main component are preferable. Particularly, a polymer film containing a polyimide or a liquid crystal polymer is suitable when a phosphor columnar crystal is formed by a vapor phase method using cesium iodide or the like as a raw material. is there. Examples of the liquid crystal polymer include polycondensates of ethylene terephthalate and parahydroxybenzoic acid, polycondensates of ethylene terephthalate and parahydroxybenzoic acid, and polycondensates of 2,6-hydroxynaphthoic acid and parahydroxybenzoic acid. Among them, a polycondensate of 2,6-hydroxynaphthoic acid and parahydroxybenzoic acid is most preferable from the viewpoint of heat resistance.

  In addition, it is preferable that the polymer film as a board | substrate based on this invention is 50-500 micrometers in thickness, and also is a polymer film which has flexibility.

Here, the “flexible substrate” means a substrate having an elastic modulus (E120) at 120 ° C. of 1000 to 6000 N / mm ² , and a polymer film containing polyimide or polyethylene naphthalate as the substrate. Is preferred.

  Note that the “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 C 2318 and the corresponding stress have a linear relationship using a tensile tester. Is what we asked for. This is a value called Young's modulus, and in the present invention, this Young's modulus is defined as an elastic modulus.

The substrate used in the present invention preferably has an elastic modulus (E120) at 120 ° C. of 1000 to 6000 N / mm ² as described above. More preferably, it is 1200-5000 N / mm < ² >.

Specifically, polyethylene naphthalate ^{(E120 = 4100N / mm 2)} , polyethylene terephthalate ^{(E120 = 1500N / mm 2)} , polybutylene naphthalate ^{(E120 = 1600N / mm 2)} , polycarbonate (E120 = 1700N / ^mm 2) , Syndiotactic polystyrene (E120 = 2200 N / mm ² ), polyetherimide (E120 = 1900 N / mm ² ), polyarylate (E120 = 1700 N / mm ² ), polysulfone (E120 = 1800 N / mm ² ), polyethersulfone Examples thereof include a polymer film made of (E120 = 1700 N / mm ² ).

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

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

(Adhesive support)
The radiological image detection apparatus of the present invention is a radiological image detection apparatus comprising a scintillator panel having a phosphor layer on a substrate for converting radiation into light on a photoelectric conversion element array arranged two-dimensionally. The scintillator panel and the photoelectric conversion element array are in close contact with each other by an atmospheric pressure via a contact support disposed on the substrate side of the scintillator panel, and the contact support is surrounded by an adhesive. It is characterized by being adhered on the photoelectric conversion element array.

  As the material for the close-contact support according to the present invention, the material for the substrate can be used.

  In the present invention, it is preferable that the thermal expansion coefficients of the substrate and the contact support are both 20 ppm / ° C. or less. More preferably, it is 10 ppm / ° C. or less. However, from the viewpoint of the effect of the present invention, the thermal expansion coefficient of the substrate is preferably larger than the thermal expansion coefficient of the adhesion support. Moreover, it is preferable that the water vapor transmission rate of a board | substrate is larger than the water vapor transmission rate of the support body for contact | adherence.

  The linear expansion coefficient is increased from 30 ° C. to 150 ° C. at a rate of 5 ° C. per minute in a nitrogen atmosphere using, for example, an EXSTAR TMA / SS6000 type thermal stress strain measuring device manufactured by Seiko Electronics Co., Ltd. After cooling to 0 ° C, the temperature is increased again at a rate of 5 ° C per minute, and the value at 30 ° C to 150 ° C is determined by measuring in tension mode with a load of 5 g. it can.

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

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

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

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

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

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

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

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

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

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

  The evaporation sources 8a and 8b contain the phosphor and heat it by a resistance heating method. Therefore, the evaporation sources 8a and 8b may be composed of an alumina crucible wound with a heater, 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 8a and 8b may be molecular beam sources by a molecular source epitaxial method.

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

<Manufacturing method of scintillator panel>
A scintillator panel manufacturing method using the scintillator panel manufacturing apparatus 1 shown in FIG. 2 will be described.

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

  Next, the inside of the vacuum vessel 2 is evacuated and adjusted to a desired degree of vacuum. Thereafter, the support holder 5 is rotated with respect to the evaporation sources 8a and 8b by the support rotation mechanism 6, and when the vacuum container 2 reaches a vacuum degree capable of vapor deposition, the phosphor is evaporated from the heated evaporation sources 8a and 8b. The phosphor is grown on the surface of the support 4 to a desired thickness.

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

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

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

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

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

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

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

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

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

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

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

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

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

(Radiation image detector)
Hereinafter, the configuration of the radiation image detection apparatus 100 including the radiation scintillator panel 12 will be described with reference to FIG. FIG. 3 is a partially broken perspective view showing a schematic configuration of the radiological image detection apparatus 100.

  A polyurethane foam (foam) 150 is disposed in the gap between the scintillator panel 12 and the protective cover 155 (a) installed on the radiation incident side of the housing 155.

  As shown in FIG. 3, the radiation image detection apparatus 100 includes a scintillator panel 12, a control unit 152 that controls the operation of the radiation image detection apparatus 100, a rewritable dedicated memory (for example, a flash memory), and the like. A memory unit 153 that is a storage unit that stores the output image signal, a power supply unit 154 that is a power supply unit that supplies power necessary to obtain the image signal by driving the radiation image detection apparatus, and the like are included in the housing. It is provided inside the body 155. The housing 155 includes a communication connector 156 for performing communication from the radiological image detection apparatus 100 to the outside as necessary, an operation unit 157 for switching the operation of the radiographic image detection apparatus 100, and completion of preparation for radiographic image capturing. And a display unit 158 indicating that a predetermined amount of image signal has been written in the memory unit 153.

  Here, if the radiographic image detection apparatus 100 is provided with a power supply unit 154 and a memory unit 153 that stores an image signal of the radiographic image, and the radiographic image detection apparatus 100 is detachable via the connector 156, the radiographic image detection apparatus is provided. It can be set as the portable structure which can carry 100.

  The radiation scintillator panel 12 is disposed on the radiation irradiation surface side, and is configured to emit an electromagnetic wave corresponding to the intensity of incident radiation.

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

(Production of substrate 1)
A reflective layer (0.10 μm) was formed by sputtering aluminum on a polyimide film having a thickness of 125 μm and a size of 250 × 200 mm (coefficient of thermal expansion of 24 ppm / ° C.) (Upilex manufactured by Ube Industries).

(Preparation of substrate 2)
It was produced under the same conditions except that it was a polyimide film having a thermal expansion coefficient of 12 ppm / ° C.

(Preparation of substrate 3)
It was produced under the same conditions except that the liquid crystal polymer film had a thermal expansion coefficient of 6 ppm / ° C.

(Preparation of undercoat layer)
Byron 20SS (Toyobo Co., Ltd .: polymer polyester resin) 300 parts by mass Coronate HX (manufactured by Nippon Polyurethane Co., Ltd .: hardener) 50 parts by mass Methyl ethyl ketone (MEK) 200 parts by mass Toluene 300 parts by mass Cyclohexanone 150 parts by mass The mixture was stirred and mixed to obtain a coating solution for undercoating. This coating solution was applied to the reflective layer side of the substrate with a spin coater so that the dry layer thickness was 1.0 μm, and then dried at 100 ° C. for 8 hours to prepare an undercoat layer.

(Formation of phosphor layer)
A phosphor (CsI: 0.03 Tlmol%) was deposited on the undercoat layer side of the substrate by using the deposition apparatus shown in FIG. 2 to form a 500 μm phosphor layer on the entire surface of the substrate. A shutter was disposed between the evaporation source and the support holder to prevent substances other than the target substance from adhering to the phosphor layer at the start of deposition.

  That is, first, a resistance heating crucible was filled as a phosphor raw material as a vapor deposition material, a substrate was placed on a rotating support holder, and the distance between the substrate and the evaporation source was adjusted to 500 mm.

  Subsequently, the inside of the vapor deposition apparatus was once evacuated, Ar gas was introduced and the degree of vacuum was adjusted to 0.5 Pa, and then the substrate temperature was maintained at 200 ° C. while rotating the substrate at a speed of 10 rpm. Next, the resistance heating crucible was heated to deposit a phosphor, thereby forming a phosphor layer having the layer thickness shown in (1) Layer thickness of Table 1.

(Method of bonding sample 1)
A scintillator panel using the substrate 1 on a TFT having an image area of 250 × 200 mm is brought into contact with the phosphor surface facing the photoelectric conversion surface of the TFT, and in the same manner as in the method of Embodiment 1 described in Japanese Patent No. 3880094. Byron 200 was applied to the end of the vacuum container so as to have a dry thickness of 5 μm, and bonded in a vacuum state.

(Method for pasting sample 2)
A scintillator panel using the substrate 1 on a TFT having an image area of 250 × 200 mm is brought into contact with the phosphor surface facing the photoelectric conversion surface of the TFT, and a thermal expansion coefficient of 255 × 205 mm of 20 ppm thickness of 125 μm from the top of the scintillator panel. The polyimide sheet was covered so that the scintillator did not protrude, and byron 200 melted around by a dispenser in a vacuum container was applied so as to have a dry film thickness of 5 μm, and bonded under reduced pressure.

(Method for pasting sample 3)
A scintillator panel using the substrate 1 on a TFT having an image area of 250 × 200 mm is brought into contact with the phosphor surface facing the photoelectric conversion surface of the TFT, and a thermal expansion coefficient of 255 × 205 mm of 20 ppm thickness of 125 μm from the top of the scintillator panel. The polyimide sheet was covered so that the scintillator did not protrude, and the byron 200 melted around the periphery was applied with a dispenser in a vacuum container so as to have a dry film thickness of 5 μm, and bonded in a reduced pressure state.

(Lamination method of samples 4 to 6)
Samples 4 to 6 were bonded in the same manner as Sample 3 except that the materials described in Table 1 were used for the combination of substrates or bonded supports. As the liquid crystal polymer, Kuraray Bexter OC was used.

(Method for pasting sample 7)
A paint having the same composition as the undercoat layer was applied to a liquid crystal polymer (Kuraray Bexter OC) having a thermal expansion coefficient of 6 ppm of 255 × 205 mm so as to have a dry thickness of 5 μm, and only the solvent was dried at 100 ° C. for 5 minutes. A bonded support was obtained. The surface opposite to the phosphor layer surface of the scintillator using the substrate 3 and the surface coated with Byron were bonded together and heated to adhere at 100 ° C. for 8 hours. This is brought into contact with a TFT having an image area of 250 × 200 mm with the phosphor surface and the photoelectric conversion surface of the TFT facing each other, and in a decompression container, by-dispensing byron 200 melted around is applied to a dry film thickness of 5 μm. And bonded together under reduced pressure.

(Evaluation method)
MTF: The lead edge was photographed at 80 kV, and the image was obtained by Fourier analysis. It was determined as a relative value with an MTF of 1 ln / mm of Sample 1 as 100.

  Edge image unevenness: X-rays of 80 kV were irradiated, the image was not corrected, the image was observed on a computer screen, and 1 cm unevenness from the edge portion was visually evaluated based on the following evaluation criteria.

  Image unevenness: Image unevenness inside 1 cm from the end was visually evaluated based on the following evaluation criteria.

  Initial characteristics: Immediately after preparing a sample, X-rays were irradiated and photographed and evaluated.

Durability evaluation: The sample was put in a thermostat at 60 ° C. and subjected to heat durability for 200 hours.
1: Many unevennesses cannot be used 2: Many unevennesses 3: There are unevennesses, but can be used 4: There are few unevennesses 5: There are no unevennesses or do not know.

  The evaluation results are shown in Table 1.

  As is clear from the results shown in Table 1, it can be seen that the examples according to the present invention are superior in the sharpness of the radiographic image and have little or no unevenness as compared with the comparative example.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of scintillator panel 2 Vacuum container 3 Vacuum pump 4 Support body 5 Support body holder 6 Support body rotating mechanism 7 Support body rotating shaft 8 Evaporation source 9 Shutter 10 Shielding plate 12 Scintillator panel 100 Radiation image detection apparatus

Claims (9)

A radiological image detection apparatus comprising a scintillator panel having a phosphor layer made of a columnar crystal that converts radiation into light on a two-dimensionally arranged photoelectric conversion element array on a substrate, the scintillator panel, The photoelectric conversion element array is in close contact with atmospheric pressure through a close contact support disposed on the substrate side of the scintillator panel, and the contact support is surrounded by an adhesive on the photoelectric conversion element array. Glued ,
The radiological image detection apparatus , wherein the phosphor layer contains a phosphor based on cesium halide (CsX; X is halogen) .   The radiographic image detection apparatus according to claim 1, wherein the adhesive and the phosphor layer are not in contact with each other.   The radiographic image detection apparatus according to claim 1, wherein the thermal expansion coefficient of the substrate and the support for contact is 20 ppm / ° C. or less.   The radiographic image detection apparatus according to any one of claims 1 to 3, wherein a thermal expansion coefficient of the substrate is larger than a thermal expansion coefficient of the support for contact.   The radiographic image detection apparatus according to any one of claims 1 to 4, wherein the moisture permeability of the substrate is larger than the moisture permeability of the support for adhesion.   The radiographic image detection apparatus according to claim 1, wherein the substrate is a flexible substrate.   The radiographic image detection apparatus according to claim 6, wherein the flexible substrate is a polymer film substrate containing polyimide.   The radiographic image detection apparatus according to claim 1, wherein the adhesive is a heat-sealing sealant or a UV curable resin. It is a manufacturing method of the radiographic image detection apparatus which manufactures the radiographic image detection apparatus as described in any one of Claims 1-8 , Comprising: When bonding a scintillator panel to a photoelectric conversion element array by the support body for contact | adhesion A method for producing a radiation image detection apparatus, wherein the photoelectric conversion element array and the support for adhesion are warmed to 20 to 150 ° C. for bonding.

Images