JP2006194860A - Radiological image conversion panel and method of manufacturing radiological image conversion panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiological image conversion panel having excellent image characteristics and vibration characteristics, and a method of manufacturing a radiological image conversion panel. <P>SOLUTION: The radiological image conversion panel has a metal plate 12 on a CFRP composite plate 13 constituted of a low-density layer (plate) having at least two sides reinforced with a reinforcing material and a CFRP (carbon fiber reinforced resin) plate bonded on one side or the two sides of the layer. The metal plate 12 is coated with a resin to form an undercoating layer, then is provided with a fluorescent layer 11 formed by the vapor deposition method and is sealed with a moistureproof protective film 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radiation image conversion panel used for medical use and a method for manufacturing a radiation image conversion panel.

  Conventionally, in order to obtain a radiographic image, a method has been employed in which an optical signal is extracted from a latent image obtained by radiation irradiation using a laser beam or the like. In order to extract an optical signal after a lapse of time after absorption of radiation, a stimulable phosphor layer is required. To provide the stimulable phosphor layer, there has been a coating method by coating conventionally. Since the coating solution contains a component such as a binder that does not contribute to light emission, a technique by a vapor deposition method such as vapor deposition has recently been used.

  In the formation of photostimulable phosphors by vapor deposition or the like, the substrate needs to be heat resistant (about 80 ° C. to 200 ° C.) due to the necessity of vapor flow or crucible radiant heat at the time of vapor deposition or substrate heating. there were. In addition, the substrate surface on which the phosphor layer is provided is required to be very smooth.

  In addition, a system in which X-rays or other irradiation radiation is incident from the substrate side requires a substrate that absorbs a small amount of X-rays, and a CFRP (carbon fiber reinforced resin) plate, and recently a composite plate using it. Etc. are considered preferable because of their rigidity.

  By the way, the surface of the substrate on which the phosphor layer is provided is required to be very smooth, and there is a method of providing a heat-resistant resin layer to make it smooth. It has been found preferable to use an aluminum plate.

  However, since the aluminum plate has a slightly larger amount of X-ray absorption than the CFRP plate and the CFRP composite plate, there is a drawback that the rigidity is lowered if it is made too thin. When the rigidity is low, the image is attached to the X-ray image conversion apparatus, and the image may be distorted by vibration when receiving an impact during X-ray image conversion.

In order to improve these, Patent Document 1 discloses that in a radiographic image reading apparatus that reads radiographic image information, when it is integrated with a photostimulable phosphor panel, the natural vibration is higher than that of the photostimulable phosphor panel alone. Although a technique for providing a vibration isolating plate that increases in number integrally with the photostimulable phosphor panel has been proposed, it has not been satisfied yet.
Japanese Patent Laid-Open No. 10-186553

  An object of the present invention is to provide a radiation image conversion panel excellent in image characteristics and vibration characteristics and a method for manufacturing the radiation image conversion panel.

  The above object of the present invention is achieved by the following configurations.

  1. A radiation image conversion panel having at least a phosphor layer on a CFRP (carbon fiber reinforced resin) composite plate, wherein the CFRP (carbon fiber reinforced resin) composite plate is reinforced with a reinforcing material on at least two sides. ), And a CFRP plate adhered to both sides or one side.

  2. 2. The radiation image conversion panel according to 1 above, wherein the phosphor layer is formed by a vapor deposition method.

  3. 3. The radiation image conversion panel according to 1 or 2, wherein the low-density layer (plate) reinforced with a reinforcing material of the CFRP (carbon fiber reinforced resin) composite plate is a foam layer.

  4). 3. The radiation image conversion panel according to 1 or 2, wherein the low density layer (plate) reinforced with a reinforcing material of the CFRP (carbon fiber reinforced resin) composite plate is a foamed polyimide plate.

  5. 5. The radiation image conversion panel according to any one of 1 to 4, wherein the reinforcing material is a CFRP (carbon fiber reinforced resin) plate, a GFRP (glass fiber reinforced resin) plate, or a paper-containing bake plate.

  6). A metal plate is provided on a CFRP (carbon fiber reinforced resin) composite plate in which a CFRP plate is bonded to both sides or one side of a low density layer (plate) reinforced with a reinforcing material on at least two sides. 6. The radiation image conversion panel according to any one of 1 to 5, wherein the radiation image conversion panel has at least a phosphor layer.

  7). 7. The radiation image conversion panel as described in 6 above, wherein the metal plate is an aluminum plate.

  8). 8. The stimulable phosphor in the phosphor layer of the radiation image conversion panel is a stimulable phosphor represented by the following general formula (1): Radiation image conversion panel.

General formula (1) CsX: yA
(In the formula, X represents Cl, Br or I, A represents Eu, Sm, In, TI, Ga or Ce. Y is 1 × 10 ⁻⁷ to 1 × 10 ⁻² )
9. The radiation image conversion panel according to any one of 6 to 8 above is formed by forming a phosphor layer on a metal plate by a vapor deposition method, sealing, and attaching the CFRP (carbon fiber reinforced resin) composite plate. A manufacturing method of a radiation image conversion panel characterized by manufacturing together.

  10. The radiation image conversion panel according to any one of 6 to 8 is coated with a resin as an undercoat layer on a metal plate, a phosphor layer is then formed by vapor deposition, sealing is performed, and the CFRP (Carbon fiber reinforced resin) A method of manufacturing a radiation image conversion panel, wherein a composite plate is bonded together.

  The radiation image conversion panel and the manufacturing method thereof according to the present invention have an excellent effect on image characteristics and vibration characteristics.

  Hereinafter, the present invention will be described in more detail.

  The invention of claim 1 of the present invention is a radiation image conversion panel having a phosphor layer on a CFRP (carbon fiber reinforced resin) composite plate, wherein the CFRP (carbon fiber reinforced resin) composite plate is made of a reinforcing material on at least two sides. A radiation image conversion panel comprising a CFRP plate bonded to both sides or one side of a reinforced low density layer (plate).

  The invention of claim 1 of the present invention is characterized in that a CFRP composite plate is used as the substrate. Even if the CFRP composite plate is a thick combination of a CFRP layer and a foamed resin layer, the amount of X-ray absorption is small and rigidity is high.

  CFRP composite plates have low X-ray absorption and excellent vibration characteristics.

  The term “excellent vibration characteristics” as used herein means that the radiation image conversion panel is attached to the image forming apparatus and is less likely to vibrate when subjected to an impact during X-ray image conversion and has little influence on the image.

  In the present invention, the CFRP composite plate usually has a structure in which two CFRP plates sandwich a low density layer (plate).

  The low-density layer (plate) is preferably a foamed layer, and more preferably a foamed polyimide plate, since it has a small amount of X-ray absorption, is excellent in vibration characteristics, and exhibits the effects of the present invention.

  The low density layer (plate) referred to in the present invention means a plate made of a material having a density lower than that of the CFRP plate.

  Of course, it may be composed of one or more CFRP plates and a low density layer (plate).

  The thickness of the substrate is preferably 0.5 mm to 7 mm. If it is less than 0.5 mm, the rigidity is insufficient and the vibration characteristics deteriorate. On the other hand, if it exceeds 7 mm, the amount of X-ray absorption increases and the image characteristics are degraded.

  Further, the present invention is characterized in that a CFRP (carbon fiber reinforced resin) composite plate is obtained by adhering a CFRP plate to both sides or one side of a low density layer (plate) in which at least two sides are reinforced with a reinforcing material. It is said.

  This is effective to prevent the radiation image conversion panel from being crushed when the radiation image conversion panel is attached to the image reader and fixed. Becomes worse.

  FIG. 1 is a schematic view showing an example in which the CFRP (carbon fiber reinforced resin) composite plate is reinforced with a reinforcing material.

  As the reinforcing material of the present invention, fiber reinforced resins such as CFRP plate and GFRP plate, resins such as PC (polycarbonate) and aramid, and a low-density layer (plate) such as metal may be higher in density and rigidity. A CFRP plate, a GFRP plate, or a paper-containing bake plate is preferable in that the effects of the present invention are further exhibited.

  The invention of claim 6 has a metal plate on a CFRP (carbon fiber reinforced resin) composite plate in which a CFRP plate is bonded to both sides or one side of a low density layer (plate) reinforced with a reinforcing material on at least two sides. The radiation image conversion panel according to claim 1, further comprising a phosphor layer on the metal plate.

  The substrate on which the phosphor layer is provided is required to be smooth, and in the invention of claim 6, it is necessary to have a highly smooth metal plate on a CFRP (carbon fiber reinforced resin) composite plate. It is a feature.

  Among these, an aluminum plate is more preferable as the metal plate because the effects of the present invention can be further achieved.

The thickness of the metal plate is preferably 0.01 mm to 3 mm. If it is less than 0.01 mm, it is difficult to handle and it is difficult to bond. If it exceeds 3 mm, the amount of X-ray absorption increases and the image characteristics are deteriorated.

  In addition, as thickness of a board | substrate, 0.5 mm-7 mm are preferable. If it is less than 0.5 mm, although it depends on the thickness of the metal plate, the rigidity is insufficient and the vibration characteristics deteriorate. On the other hand, if it exceeds 7 mm, the amount of X-ray absorption increases and the image characteristics are degraded.

  As for the rigidity of the substrate with the metal plate and carbon plate bonded together, the rigidity value in the vertical direction (vertical direction when attached to the device) is 10 to 500 N · m and the horizontal value (horizontal direction when attached to the device). The rigidity value is preferably 5 to 400 N · m. This rigidity can be adjusted by the type and thickness of the metal plate, the type and thickness of the carbon plate, but it is quite difficult and costly to produce a substrate having a numerical value that exceeds the upper limit of the rigidity value.

  The structure other than the metal plate is synonymous with the invention of claim 1 described above.

Manufacturing method of radiation image conversion panel The invention of claim 9 is a method for forming a radiation image conversion panel according to any one of claims 6 to 8 by forming a phosphor layer on a metal plate by a vapor deposition method and sealing it. And manufacturing the radiation image conversion panel, wherein the CFRP (carbon fiber reinforced resin) composite plate is bonded and manufactured.

  In the invention of claim 10, the radiation image conversion panel according to any one of claims 6 to 8 is coated with a resin as an undercoat layer on a metal plate, and then a phosphor layer is formed by vapor deposition. Forming, sealing, and bonding the CFRP composite plate together to manufacture a radiation image conversion panel.

  The undercoat layer may be a resin layer, but may be other than that.

  Next, the stimulable phosphor represented by the following general formula (A) preferably used in the present invention will be described.

Formula (A)
M ¹ X · aM ² X ′ · bM ³ X ″: eA
[Wherein, M ¹ is at least one alkali metal atom selected from Li, Na, K, Rb and Cs atoms, and M ² is Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu. And at least one divalent metal atom selected from each atom of Ni, and M ³ is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, At least one trivalent metal atom selected from each atom of Tm, Yb, Lu, Al, Ga and In, and X, X ′ and X ″ are at least selected from each atom of F, Cl, Br and I 1 type of halogen atom, A is Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg. At least one metal atom selected from each atom, and a, b, e each represent a number between 0 ≦ a <0.5,0 ≦ b <0.5,0 <e ≦ 0.2.]
Among these, in the present invention, the photostimulable phosphor represented by the general formula (1) is more preferable.

In the general formula (1), X represents Cl, Br, or I, and A represents Eu, Sm, In, Tl, Ga, or Ce. y represents a numerical value from 1 × 10 ⁻⁷ to 1 × 10 ⁻² .

  The photostimulable phosphor is manufactured, for example, by the manufacturing method described below.

  First, as a phosphor material, an acid (HI, HBr, HCl, HF) is added to a carbonate so as to have the following composition, mixed and stirred, and then filtered at a neutralization point. Is evaporated to produce the following crystals.

As the phosphor material,
(A) At least one compound selected from NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KI, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr and CsI is used.

_{(B) MgF 2, MgCl 2} , MgBr 2, MgI 2, CaF 2, CaCl 2, CaBr 2, CaI 2, SrF 2, SrCI 2, SrBr 2, SrI 2, BaF 2, BaCl 2, BaBr 2, BaBr 2 2H ₂ O, BaI ₂ , ZnF ₂ , ZnCl ₂ , ZnBr ₂ , ZnI ₂ , CdF ₂ , CdCl ₂ , CdBr ₂ , CdI ₂ , CuF ₂ , CuCl ₂ , CuBr ₂ , CuI, NiF ₂ , NiCl ₂ , NiBr _At least one compound selected from ₂ and NiI ₂ compounds is used.

  (C) In the general formula (A), Eu, Tb, In, Cs, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu And a compound having a metal atom selected from each atom such as Mg.

  (D) The activator A includes, for example, Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu, and Mg. At least one metal atom selected from atoms is used.

  In the compound represented by the general formula (A), a is 0 ≦ a <0.5, preferably 0 ≦ a <0.01, b is 0 ≦ b <0.5, preferably 0 ≦ b ≦ 0. 01 and e are 0 <e ≦ 0.2, preferably 0 <e ≦ 0.1.

  The phosphor materials (a) to (d) are weighed so as to have a mixed composition in the above numerical range, and dissolved in pure water.

  At this time, the mixture may be sufficiently mixed using a mortar, ball mill, mixer mill or the like.

  Next, a predetermined acid is added so that the pH value C of the obtained aqueous solution is adjusted to 0 <C <7, and then water is evaporated.

  Next, the obtained raw material mixture is filled in a heat-resistant container such as a quartz crucible or an alumina crucible and fired in an electric furnace. The firing temperature is preferably 500 to 1000 ° C. The firing time varies depending on the filling amount of the raw material mixture, the firing temperature and the like, but is preferably 0.5 to 6 hours.

  The firing atmosphere includes a nitrogen gas atmosphere containing a small amount of hydrogen gas, a weak reducing atmosphere such as a carbon dioxide gas atmosphere containing a small amount of carbon monoxide, a neutral atmosphere such as a nitrogen gas atmosphere and an argon gas atmosphere, or a small amount of oxygen gas. A weak oxidizing atmosphere is preferred.

  After firing once under the above firing conditions, the fired product is taken out from the electric furnace and pulverized, and then the fired product powder is again filled in a heat-resistant container and placed in the electric furnace, and again under the same firing conditions as described above. If the calcination is performed, the emission luminance of the phosphor can be further increased. When the baked product is cooled to the room temperature from the calcination temperature, the desired fluorescence can also be obtained by removing the baked product from the electric furnace and allowing it to cool in air. The body can be obtained, but it may be cooled in the same weakly reducing atmosphere or neutral atmosphere as at the time of firing. In addition, by moving the fired product from the heating unit to the cooling unit in an electric furnace and quenching in a weak reducing atmosphere, neutral atmosphere or weak oxidizing atmosphere, the emission luminance due to the phosphor phosphors obtained can be increased. It can be further increased.

  The photostimulable phosphor layer of the present invention is preferably formed by a vapor deposition method.

  Vapor deposition, sputtering, CVD, ion plating, and others can be used as the vapor deposition method of the photostimulable phosphor.

  In the present invention, for example, the following methods can be mentioned.

In the vapor deposition method of the first method, first, after the support is installed in the vapor deposition apparatus, the inside of the apparatus is evacuated to a degree of vacuum of about 1.333 × 10 ⁻⁴ Pa.

  Next, at least one of the photostimulable phosphor is heated and evaporated by a resistance heating method, an electron beam method, or the like to grow the photostimulable phosphor on the surface of the support to a desired thickness.

  As a result, a photostimulable phosphor layer containing no binder is formed, but it is also possible to form the photostimulable phosphor layer in a plurality of times in the vapor deposition step.

  In the vapor deposition step, it is possible to co-evaporate using a plurality of resistance heaters or electron beams to synthesize the desired photostimulable phosphor on the support and simultaneously form the photostimulable phosphor layer. is there.

  After vapor deposition is completed, the radiation image conversion panel of the present invention is manufactured by providing a protective layer on the side opposite to the support side of the photostimulable phosphor layer as necessary. In addition, after forming a photostimulable phosphor layer on a protective layer, a procedure for providing a support may be taken.

  Furthermore, in the vapor deposition method, the vapor deposition target (support, protective layer or intermediate layer) may be cooled or heated as necessary during vapor deposition.

Further, the stimulable phosphor layer may be heat-treated after the vapor deposition. 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 sputtering method as the second method, like the vapor deposition method, after a support having a protective layer or an intermediate layer is placed in the sputtering apparatus, the inside of the apparatus is once evacuated to about 1.333 × 10 ⁻⁴ Pa. The degree of vacuum is set, and then an inert gas such as Ar or Ne is introduced into the sputtering apparatus as a sputtering gas to obtain a gas pressure of about 1.333 × 10 ⁻¹ Pa. Next, a stimulable phosphor layer is grown on the support to a desired thickness by sputtering using the stimulable phosphor as a target.

  Various applied treatments can be used in the sputtering step as in the vapor deposition method.

  The third method is a CVD method, and the fourth method is an ion plating method.

  The growth rate of the stimulable phosphor layer in the vapor phase growth is preferably 0.05 μm / min to 300 μm / min. When the growth rate is less than 0.05 μm / min, the productivity of the radiation image conversion panel of the present invention is unfavorable. If the growth rate exceeds 300 μm / min, it is difficult to control the growth rate.

  When the radiation image conversion panel is obtained by the above-described vacuum deposition method, sputtering method, etc., since there is no binder, the packing density of the stimulable phosphor can be increased, and preferable radiation image conversion in terms of sensitivity and resolution. A panel is obtained and preferred.

  The film thickness of the photostimulable phosphor layer varies depending on the intended use of the radiation image conversion panel and the type of photostimulable phosphor, but is 50 μm to 1 mm, preferably 50 from the viewpoint of obtaining the effects of the present invention. It is -500 micrometers, More preferably, it is 100-500 micrometers.

  In producing the photostimulable phosphor layer by the vapor phase growth method described above, the temperature of the support on which the photostimulable phosphor layer is formed is preferably set to 40 ° C. or more, more preferably 40 to 150. ° C.

  Since the photostimulable phosphor layer formed on the support in this manner does not contain a binder, it has excellent directivity, high directivity of stimulated excitation light and stimulated emission, and high brightness. The layer thickness can be made thicker than that of a radiation image conversion panel having a dispersive stimulable phosphor layer in which a stimulable phosphor is dispersed in a binder. Furthermore, the sharpness of the image is improved by reducing the scattering of the stimulating light in the stimulable phosphor layer.

  In addition, the gap between the columnar crystals may be filled with a filler or the like, and in addition to reinforcing the stimulable phosphor layer, it may be filled with a high light absorption substance, a high light reflectance substance, or the like. Thus, in addition to providing the above-mentioned reinforcing effect, it is effective for reducing the light diffusion in the lateral direction of the stimulated excitation light incident on the stimulable phosphor layer.

  A highly reflective substance refers to a substance having a high reflectivity with respect to stimulated excitation light (500 to 900 nm, particularly 600 to 800 nm). For example, white pigments such as aluminum, magnesium, silver, indium, and other metals In addition, a color material in the green to red region can be used. White pigments can also reflect stimulated emission.

Examples of the white pigment 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 Ba, At least one selected from 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 , lithopone (BaSO _4. ZnS), magnesium silicate, basic silicate, basic lead phosphate, aluminum silicate and the like.

  These white pigments have a strong hiding power and a high refractive index, so that it is possible to easily scatter scattered light by reflecting or refracting light, and to significantly improve the sensitivity of the resulting radiation image conversion panel. it can.

  In addition, as a material having a high light absorption rate, for example, carbon black, chromium oxide, nickel oxide, iron oxide, and the like and a blue color material are used. Among these, carbon black absorbs stimulated light emission.

  The color material may be either an organic or inorganic color material.

  Examples of organic colorants include Zavon First Blue 3G (Hoechst), Estrol Brill Blue N-3RL (Sumitomo Chemical), D & C Blue No. 1 (made by National Aniline), Spirit Blue (made by Hodogaya Chemical), Oil Blue No. 1 603 (made by Orient), Kitten Blue A (made by Ciba Geigy), Eisen Katyron Blue GLH (made by Hodogaya Chemical), Lake Blue AFH (made by Kyowa Sangyo), Primocyanin 6GX (made by Inabata Sangyo), Brill Acid Green 6BH (Hodogaya) Chemical Blue), Cyan Blue BNRCS (Toyo Ink), Lionoyl Blue SL (Toyo Ink), etc. are used.

  In addition, the color index No. 24411, 23160, 74180, 74200, 22800, 23154, 23155, 24401, 14830, 15050, 15760, 15707, 17941, 74220, 13425, 13361, 13420, 11836, 74140, 74380, 74350, 74460, etc. There are also materials.

Examples of the inorganic color material include inorganic pigments such as ultramarine blue, for example, cobalt blue, cerulean blue, chromium oxide, and TiO ₂ —ZnO—CoO—NiO.

  Moreover, the photostimulable phosphor layer of the present invention may have a protective layer.

  The protective layer may be formed by directly applying a protective layer coating solution on the photostimulable phosphor layer, or a protective layer separately formed in advance may be adhered on the photostimulable phosphor layer. Alternatively, a means for forming a stimulable phosphor layer on a separately formed protective layer may be taken.

  Materials for the protective layer include cellulose acetate, nitrocellulose, polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene terephthalate, polyethylene, polyvinylidene chloride, nylon, polytetrafluoroethylene, polytrifluoride-chloride. Usual protective layer materials such as ethylene, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer are used. In addition, a transparent glass substrate can be used as a protective layer.

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

  The thickness of these protective layers is preferably 0.1 to 2000 μm.

  FIG. 2 is a schematic diagram showing an example of a basic configuration of the radiation image conversion panel of the present invention. In order to more reliably reduce the ingress of moisture into a phosphor that is cut to a predetermined size and has a photostimulable phosphor layer on the support, the photostimulability deposited on the substrate is reduced. By adhering and sealing with a protective film from above the phosphor layer, it is possible to prevent moisture from entering from the outer peripheral portion of the phosphor.

  In FIG. 2, 11 represents a stimulable phosphor layer (vapor phase deposition type), 13 is a CFRP or CFRP composite plate, 12 is a metal plate, and 14 is a moisture-proof protective film. 12 and 13 constitute the substrate.

  The sealing structure of the present invention is formed into a bag shape using two laminated protective films A (no heat fusion) described in the examples described later, and the stimulable phosphor plate is wrapped under reduced pressure, and on the phosphor layer surface side. In an area outside the periphery of the phosphor, the upper and lower moisture-proof protective films are heated and fused with an impulse sealer or the like and sealed. Thereafter, a CFRP plate or a CFRP composite plate is bonded to produce a radiation image conversion panel.

  The heat-fusible film here refers to a resin film that can be fused with a commonly used impulse sealer, such as ethylene vinyl acetate copolymer (EVA), polypropylene (PP) film, polyethylene (PE) film, and the like. The present invention is not limited to these examples.

  As the film preferably used for the protective layer of the present invention, when the fusion film is used, the optimum moisture resistance can be achieved by laminating a plurality of fusion films in accordance with the required moisture resistance. . As a laminating method in this case, any generally known method may be used, but preferably a dry laminating method is excellent in terms of workability.

  The outer surface on the opposite side of the phosphor layer having the protective layer is matted, and the average inclination angle Δa of the surface roughness of the protective layer is 0.01 to 0.1. In the image conversion panel, it is more preferable.

  Here, the average inclination angle Δa of the surface roughness is an arithmetic average inclination angle Δa according to JIS-B-0601 (1998).

  Resin films with various surface shapes are widely available on the market, and it is easy to select a film having the required average inclination angle Δa.

  Films such as polypropylene film, polyethylene terephthalate film, and polyethylene naphthalate film have excellent physical properties as a protective film in terms of strength. A part of the light is repeatedly reflected at the upper and lower interfaces of the film and propagates to a place away from the scanned place, emitting a stimulated emission and reducing sharpness. In addition, the excitation light reflected in the opposite direction to the phosphor layer surface at the upper and lower interfaces of the protective film is re-reflected between the photodetection devices and the peripheral members, so that the photostimulability of the place further away from the scanned place is achieved. Since the phosphor layer is excited to emit stimulated light emission, this further reduces sharpness. Since the excitation light is coherent light with a long wavelength from red to infrared, unless it actively absorbs scattered light or reflected light, the amount absorbed in the space inside the protective film or inside the reader is small and far away. It propagates to a new place and sharpness deteriorates.

  For this reason, it is preferable to provide an excitation light absorption layer presumed to have an effect of suppressing the scattered light and reflected light.

  The excitation light absorbing layer is a layer containing a colorant that selectively absorbs excitation light. As described later, these layers are coated on one surface of the protective film. Alternatively, it may be coated on both surfaces, or the protective film itself may be colored to form an excitation light absorbing layer.

  In addition, when a film such as a polypropylene film, a polyethylene terephthalate film, or a polyethylene naphthalate film is used as a component of the protective layer according to the present invention, the density other than the radiographic image of the subject, that is, image unevenness, or during the manufacturing process of the protective film Linear noise that seems to be caused is reduced.

  This effect becomes remarkable when the average inclination angle Δa is 0.01 or more.

  It is presumed that the total reflection of excitation light at the protective layer (protective film) interface is prevented at an inclination angle Δa near this value, but this effect is small when the protective film is not provided with an excitation light absorbing layer. From the above, it is presumed that the above effect is a synergistic effect of the anti-scattering effect of the excitation light absorbing layer and the total reflection prevention of the average inclination angle Δa of the surface roughness.

  According to the present invention, a protective film having high heat resistance can be used at a necessary thickness without deteriorating the image quality without impairing water resistance, moisture resistance and solvent resistance required as a protective layer material. The radiation image conversion panel with excellent heat resistance can be realized.

  When using a resin film for a protective film, it can be set as the structure which laminated | stacked the vapor deposition film which vapor-deposited the metal oxide etc. on the resin film or the resin film according to the flaw resistance and moisture resistance required.

  In addition, when a plurality of films are laminated as described above, an excitation light absorption layer is further provided between the laminated resin films, so that the excitation light absorption layer is protected from physical impact and chemical alteration and stable. The plate performance is more preferable because it can be maintained for a long time. The excitation light absorption layer may be provided at a plurality of locations, or a colorant may be included in the adhesive layer for laminating the resin film to form the excitation light absorption layer.

  The surface shape of the protective film can be easily adjusted by selecting a resin film to be used or by applying a coating film containing an inorganic substance on the resin film surface. It is also possible to color this coating film to form an excitation light absorbing layer. Furthermore, in recent years, resin films having an arbitrary surface shape are easily available.

  As described above, Japanese Patent Publication No. 59-23400 discloses a radiation image conversion panel for coloring the protective film of the excitation light absorbing layer radiation image conversion panel, suppressing scattered light and reflected light, and improving sharpness. Are described as an example of various embodiments in which each of the support, the undercoat layer, the phosphor layer, the intermediate layer, and the protective layer constituting the substrate is colored.

  As the colorant preferably used in the protective layer of the radiation image conversion panel in the present invention, a colorant having a property of absorbing excitation light of the radiation image conversion panel is preferably used.

  Preferably, the light transmittance of the protective film at the excitation light wavelength is 98% to 50% of the light transmittance of the protective film which is different only in that the excitation light absorption layer is not provided (for example, He—Ne laser light (633 nm). )) To provide an excitation light absorption layer. When the light transmittance exceeds 98%, the effect of the present invention is small. When the light transmittance is less than 50%, the luminance of the radiation image conversion panel rapidly decreases.

  Which colorant is used depends on the type of stimulable phosphor used in the radiation image conversion panel, but as a stimulable phosphor for the radiation image conversion panel, the excitation is usually in the range of 400 to 900 nm. A phosphor exhibiting stimulated emission in the wavelength range of 300 to 500 nm by light is used. For this reason, a blue to green organic or inorganic colorant is usually used as the colorant.

Examples of blue to green organic colorants include Zavon Fast Blue 3G (Hoechst), Estrol Brill Blue N-3RL (Sumitomo Chemical), Sumiacryl Blue F-GSL (Sumitomo Chemical), D & C Blue No. 1 (National Aniline), Spirit Blue (Hodogaya Chemical), Oil Blue No. 1 603 (manufactured by Orient), Kitten Blue A (manufactured by Ciba-Geigy), Eisen Katyron Blue GLH (manufactured by Hodogaya Chemical Co., Ltd.), Lake Blue A, F, H (manufactured by Kyowa Sangyo Co., Ltd.), Rhodaline Blue 6GX ( Kyowa Sangyo Co., Ltd.), Brimocyanin 6GX (Inabata Sangyo Co., Ltd.), Brill Acid Green 6BH (Hodogaya Chemical Co., Ltd.), Cyanine Blue BNRS (Toyo Ink Co., Ltd.), Lionol Blue SL (Toyo Ink Co., Ltd.) . Examples of blue to green inorganic colorants include, but are not limited to, ultramarine blue, cobalt blue, cerulean blue, chromium oxide, and TiO ₂ —ZnO—CoO—NiO pigments.

Stimulable phosphor layer (phosphor layer)
Next, the phosphor constituting the radiation image conversion panel by covering with the protective film will be described.

  The columnar crystals obtained by using these photostimulable phosphors that are preferable in the present invention, that is, the crystals growing in columnar form with a certain gap are described in JP-A-2-58000. Can be obtained by different methods.

  That is, a photostimulable phosphor layer composed of independent elongated columnar crystals can be obtained by supplying vapor of the stimulable phosphor or the raw material onto a substrate and performing vapor phase growth (deposition) such as vapor deposition.

  For example, by making the vapor flow of the photostimulable phosphor at the time of vapor deposition enter in the range of 0 to 5 degrees with respect to the direction perpendicular to the substrate, it is possible to obtain crystals that are substantially perpendicular to the substrate surface.

  In these cases, it is appropriate that the distance between the shortest part of the substrate and the crucible is usually set to 10 cm to 80 cm in accordance with the average range of the stimulable phosphor.

  The stimulable phosphor as an evaporation source is uniformly dissolved or formed by pressing or hot pressing and charged in a crucible. At this time, it is preferable to perform a degassing treatment. The method of evaporating the photostimulable phosphor from the evaporation source is usually performed by scanning an electron beam emitted from an electron gun, but it can be evaporated by other methods.

  The evaporation source is not necessarily a stimulable phosphor, and may be a mixture of a stimulable phosphor material.

  Moreover, what activator mixed the activator with respect to a base substance (basic substance) may be vapor-deposited, and after depositing only a base material, you may dope an activator afterwards. For example, when the base is CsBr, after depositing only CsBr, for example, In that is an activator may be doped. That is, since the crystals are independent, the film can be sufficiently doped even if the film is thick, and the crystal transfer hardly occurs, so that the modulation transfer function (MTF) does not decrease.

  Doping can be performed by thermal diffusion and ion implantation of a doping agent (activator) in the base layer of the formed phosphor.

  As a constituent material of the support (substrate), in addition to the above-described carbon fiber reinforced resin (CFRP), CFRP composite, aluminum plate, for example, plate glass such as quartz, borosilicate glass, chemically tempered glass, crystallized glass, etc. Using plastic film such as cellulose acetate film, polyester film, polyamide film, polyimide film, fluorine resin film, acrylic film, polycarbonate film, syndiotactic polystyrene (SPS) film, metal sheet such as iron, copper, chromium Also good.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, the embodiment of this invention is not limited to these.

Example 1
<< Preparation of Radiation Image Conversion Panel 1 >>
A radiation image conversion panel 1 having a photostimulable phosphor layer was produced according to the method described below.

(Preparation of photostimulable phosphor plate)
After setting an aluminum substrate (Sumitomo Light Metal A1100 XL type) having a thickness of 0.5 mm and a 460 mm square size in a vacuum chamber of a known vapor deposition apparatus so that the distance between the substrate and the vapor deposition source is 60 cm, CsBr: 0.001 Eu An alkali halide phosphor made of the above is put in a crucible, and argon gas is introduced into the vacuum chamber while evacuating, the vacuum degree is set to 0.1 Pa, the substrate temperature is set to 80 ° C., and an aluminum slit is used. The phosphor plate having a columnar structure with a thickness of 400 μm was formed by carrying out vapor deposition at a liquid temperature in the crucible of 750 ° C. while conveying the substrate in a direction parallel to the substrate.

(Sealing with moisture-proof sealing film)
A laminated protective film A including an alumina-deposited polyethylene terephthalate resin layer represented by the following configuration was produced.

Laminated protective film A: VMPET12 /// VMPET12 /// PET /// CPP20
In the laminated protective film A, VMPET represents polyethylene terephthalate vapor deposited with alumina (commercial product: manufactured by Toyo Metallizing Co., Ltd.), PET represents polyethylene terephthalate, and CPP represents cast polypropylene.

  In addition, the above “///” indicates that the thickness of the two-component reaction type urethane adhesive layer in the dry lamination adhesive layer is 3.0 μm, and the number displayed after each resin film is the number of each film. Represents film thickness (μm).

  Further, as a protective film on the substrate side of the phosphor plate, a laminate of cast polypropylene (CPP) 30 μm, aluminum film 9 μm, and polyethylene terephthalate (PET) 188 μm was produced.

  The photostimulable phosphor plate is wrapped with the above two kinds of protective films, and the upper and lower moisture-proof protective films are heated and fused with an impulse sealer or the like in a region outside the periphery of the phosphor plate while reducing the pressure. Stopped.

(Carbon plate pasting)
A carbon fiber reinforced resin plate having a thickness of 0.6 mm and a 500 mm square size in which a peripheral portion of a 2.8 mm thick and 460 mm square size foamed polyimide plate (Rohacell) is surrounded by a 20 mm wide paper bake plate in a frame shape The radiation image conversion panel 1 was prepared by attaching two substrates (E3040822 manufactured by Toray Industries, Inc.) bonded to both sides of the foamed polyimide plate to the sealed photostimulable phosphor plate with a double-sided tape from the aluminum substrate side.

Examples 2 to 4, 6 and Comparative Examples 1 and 2
Radiation image conversion panels 2 to 7 were produced in the same manner as in Example 1 except that the substrate configuration was changed as shown in Table 1. However, the reinforcing material portion of the CFRP composite plate of Example 6 was a GFRP plate.

Example 5
The above except that a substrate having a thickness of 0.5 mm, a 500 mm square aluminum substrate (Sumitomo Light Metal A1100XL type) and a 2 μm thick polyester layer (Toyobo's Byron 200) was used as the undercoat layer. A radiation image conversion panel 8 was produced in the same manner as in Example 1.

  The reinforcing material portion of the CFRP composite plate was a CFRP plate.

Comparative Example 3
A radiation image conversion panel 9 was produced with the same substrate configuration as in Example 5 except that no reinforcing material was used.

  Each obtained radiation image conversion panel was evaluated as follows. The results are shown in Table 1.

(Characteristic evaluation of radiation image conversion panel)
Both sensitivity and sharpness should be excellent.

・ Evaluation of sensitivity Sensitivity is measured by irradiating the radiation image conversion panel with X-rays with a tube voltage of 80 kVp at 10 mAs at a distance of 2 m between the radiation source and the plate, and then applying the radiation image conversion panel to Regius 350 (Konica Minolta Co., Ltd.). Installed and read. Evaluation was performed based on the electrical signal from the obtained photomultiplier.

  The sensitivity in the table is an average value of the entire phosphor surface, and is a relative sensitivity when the sensitivity of the sample 1 is 1.00.

-Evaluation of sharpness Sharpness was evaluated by obtaining a modulation transfer function.

  After attaching a CTF chart to the radiation image conversion radiation image conversion panel sample, the radiation image conversion panel sample was irradiated with 80 kVp X-rays at 10 mAs (distance to the subject: 1.5 m), and then a semiconductor laser having a diameter of 100 μmφ (680 nm) : The CTF chart image was scanned and read using a power of 40 mW on the panel). The values in the table showed an MTF value of 2.0 lp / mm. The higher the value, the better the sharpness.

(Vibration evaluation of radiation image conversion panel)
(Vibration special evaluation)
X-rays with a tube voltage of 80 kVp were irradiated at a distance of 2 m between the radiation source and the plate at 200 mAs. After that, on the front plate just in front of the radiation image conversion panel of the radiological image conversion device, a hard tennis ball suspended from the grip bar at the top of the device is used with a spacer and set 5 cm away from the front plate. A vibration was applied to the face plate from the line irradiation, and the signal value step difference of the horizontal streak generated at that time was analyzed. (The horizontal streak has a higher signal value than the surrounding area. Data of the signal value step difference with the surrounding area is obtained. The smaller the step difference, the better.)
○ ... step difference 0 to less than 2 ○ △ ... step difference 2 to less than 6 Δ ... step difference 6 to less than 11 × ... step difference 11 or more

  As is apparent from Table 1, it can be seen that the radiation image conversion panel of the present invention is excellent in both emission luminance (sensitivity) and sharpness, and in good vibration characteristics.

It is the schematic which shows an example by which the CFRP (carbon fiber reinforced resin) composite board was reinforced with the reinforcing material. It is the schematic which shows an example of the fundamental structure of the radiographic image conversion panel of this invention.

Explanation of symbols

1 CFRP (carbon fiber reinforced resin) composite plate 2 Reinforcement material 3 Foam material (low density plate)
4 CFRP plate 11 Stimulable phosphor layer 12 Metal plate 13 CFRP composite plate 14 Moisture-proof protective film

Claims (10)

A radiation image conversion panel having at least a phosphor layer on a CFRP (carbon fiber reinforced resin) composite plate, wherein the CFRP (carbon fiber reinforced resin) composite plate is reinforced with a reinforcing material on at least two sides. ), And a CFRP plate adhered to both sides or one side. The radiation image conversion panel according to claim 1, wherein the phosphor layer is formed by a vapor deposition method. The radiation image conversion panel according to claim 1 or 2, wherein the low-density layer (plate) reinforced with a reinforcing material of the CFRP (carbon fiber reinforced resin) composite plate is a foam layer. 3. The radiation image conversion panel according to claim 1, wherein the low density layer (plate) reinforced with a reinforcing material of the CFRP (carbon fiber reinforced resin) composite plate is a foamed polyimide plate. The radiation image conversion panel according to any one of claims 1 to 4, wherein the reinforcing material is a CFRP (carbon fiber reinforced resin) plate, a GFRP (glass fiber reinforced resin) plate, or a paper-containing bake plate. . A metal plate is provided on a CFRP (carbon fiber reinforced resin) composite plate in which a CFRP plate is bonded to both sides or one side of a low density layer (plate) reinforced with a reinforcing material on at least two sides. The radiation image conversion panel according to claim 1, comprising at least a phosphor layer. The radiation image conversion panel according to claim 6, wherein the metal plate is an aluminum plate. 8. The stimulable phosphor in the phosphor layer of the radiation image conversion panel is a stimulable phosphor represented by the following general formula (1). The radiation image conversion panel described.
General formula (1) CsX: yA
(In the formula, X represents Cl, Br or I, A represents Eu, Sm, In, TI, Ga or Ce. Y is 1 × 10 ⁻⁷ to 1 × 10 ⁻² ) The radiation image conversion panel according to any one of claims 6 to 8, wherein a phosphor layer is formed on a metal plate by a vapor deposition method, sealing is performed, and the CFRP (carbon fiber reinforced resin) composite plate is formed. A method for producing a radiation image conversion panel, characterized by being bonded together. The radiation image conversion panel according to any one of claims 6 to 8 is subjected to resin coating as a subbing layer on a metal plate, then a phosphor layer is formed by vapor deposition, sealing is performed, and A method for producing a radiation image conversion panel, wherein a CFRP (carbon fiber reinforced resin) composite plate is bonded together.

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