JP2004093560A - Radiation image conversion panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation image conversion panel assuring a high sensitivity, high moistureproofness, and excellent durability, generating images of good workmanship, and capable of making service in good condition for a long period of time. <P>SOLUTION: The radiation image conversion panel is structured so that a stimulable phosphor layer 2 is formed on a support 3 by means of evaporation and includes a protection layer 4 structured by a vacuum deposition process so that a fundamental inorganic layer 6, a first higher order inorganic layer 7, a second higher order inorganic layer 8 are formed on a base material 5 in the sequence as named. That side of the protection layer positioned with the second higher order inorganic layer 8 and the phosphor layer 2 are adhered together by adhesive or subjected to a decompressive lamination process. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a radiation image conversion panel used in a radiation image conversion method using a stimulable phosphor.

For example, a radiation image conversion method using a photostimulable phosphor as described in Patent Document 1 is known as an alternative to the conventional radiographic method. This method uses a radiation image conversion panel (storable phosphor sheet) containing a stimulable phosphor, and the radiation transmitted through the subject or emitted from the subject is the stimulable phosphor of the panel. Then, the stimulable phosphor is excited in a time series with electromagnetic waves (excitation light) such as visible light and infrared light, and the radiation energy accumulated in the stimulable phosphor is fluorescent ( The fluorescence is photoelectrically read to obtain an electrical signal, and then a radiographic image of the subject or subject is reproduced as a visible image based on the obtained electrical signal. The panel which has finished reading is prepared for the next photographing after the remaining image is erased. That is, the radiation image conversion panel is used repeatedly.

According to this radiographic image conversion method, it is possible to obtain a radiographic image with a large amount of information with a much smaller exposure dose than in the case of the radiographic method using a combination of a conventional radiographic film and an intensifying screen. There is an advantage that you can. Furthermore, the conventional radiographic method consumes a radiographic film for each radiographing, whereas this radiographic image conversion method uses a radiographic image conversion panel repeatedly, which is advantageous from the viewpoint of resource protection and economic efficiency. It is.

As described above, the radiation image conversion method is a very advantageous image forming method. However, the radiation image conversion panel used in this method is high in sensitivity and good like the intensifying screen used in conventional radiography. It is desirable to provide an image quality and to have a capability of withstanding long-term use without degrading the image quality of the radiation image.

However, photostimulable phosphors used in the production of radiation image conversion panels are generally highly hygroscopic and absorb moisture in the air when left in a room with normal climatic conditions. There was a problem that the radiation sensitivity of the resin deteriorated and deteriorated with time.

In general, the latent image of the radiographic image recorded on the photostimulable phosphor is regressed with the lapse of time after irradiation, so that the intensity of the reconstructed radiographic image signal is scanned from the irradiation to the excitation light. However, if the stimulable phosphor absorbs moisture, the latent image retraction speed increases, so when using a radiation image conversion panel having a moisture-stimulated phosphor. The reproducibility of the reproduction signal at the time of reading the radiation image tended to decrease.

In order to prevent the deterioration phenomenon due to moisture absorption of the photostimulable phosphor as described above, the photostimulable phosphor is coated with, for example, a film of ethylene trifluorochloride as a moisture-proof protective layer having a low moisture permeability. Thus, a method of reducing moisture reaching the phosphor layer has been taken. However, the films of ethylene trifluorochloride and the like are expensive and large in thickness, and have a problem that the environmental load is large because they are made from chlorofluorocarbon.

In order to solve such a problem, for example, Patent Document 2 describes a configuration in which a higher hygroscopic layer is provided on the phosphor layer side among two types of protective layers having different hygroscopic properties. Patent Document 3 describes a configuration in which a silicon compound containing nitrogen and oxygen is contained in a protective layer. However, the moisture proof achieved by the configurations described in Patent Document 2 and Patent Document 3 is not always satisfactory.

Patent Document 4 describes a method of using a laminated film obtained by laminating 2 to 8 films obtained by vapor-depositing a thin film such as a metal oxide or silicon nitride on a polyethylene terephthalate (PET) film. ing.

On the other hand, for a radiation image conversion panel, in Patent Document 5, a laminated film formed by laminating a plurality of resin films including a resin film on which at least one metal oxide is deposited is provided on the phosphor layer surface side. Are listed.
Japanese Patent Laid-Open No. 55-12145 Japanese Examined Patent Publication No. 4-76440 Japanese Patent No. 1927597 Japanese Patent Laid-Open No. 10-12376 JP-A-11-344698

However, the method described in Patent Document 4 causes problems such as image defects caused by the moisture-proof protective film and image defects caused by the adhesion state between the moisture-proof protective film and the phosphor surface, and is used exclusively for disease diagnosis. It cannot be employed as a moisture-proof protective film for a radiation image conversion panel. Further, in the radiation image conversion panel described in Patent Document 5, since the laminated film is adhered by the adhesive layer, unevenness occurs in the image depending on the adhesion state, and the entire moisture-proof layer becomes thick and the image quality deteriorates. There is a problem that it ends up.

The present invention has been made in view of the above circumstances, and provides a radiation image conversion panel that is excellent in moisture resistance and durability, and that can be used in a good condition for a long period of time and provides high sensitivity and good image quality. It is the purpose.

The radiation image conversion panel of the present invention is a radiation image conversion panel having a stimulable phosphor layer and a protective layer, wherein the protective layer is a basic inorganic layer and at least one upper inorganic layer located on the basic inorganic layer; Each upper inorganic layer is directly laid on an inorganic layer located below each inorganic layer.

Direct means that the inorganic layers are formed by a dry process method such as sputtering, PVD method (Physical Vapor Deposition), CVD method, or wet process such as sol-gel method, and are in close contact with each other. Means that it is not glued.

The upper inorganic layer is at least one layer, and more preferably two or more layers. The layer thickness of any one of the upper inorganic layers is preferably larger than the layer thickness of the basic inorganic layer. In this case, the layer thickness of the upper inorganic layer having a layer thickness larger than that of the basic inorganic layer is more preferably in the range of 20 to 1000 nm, and more preferably in the range of 30 to 500 nm.

Among the basic inorganic layer and the upper inorganic layer, it is preferable that at least one pair of adjacent inorganic layers have different crystal structures. The at least one pair of inorganic layers adjacent to each other is preferably an upper inorganic layer having a layer thickness larger than the layer thickness of the basic inorganic layer and an inorganic layer positioned below the inorganic layer, but constitutes a protective layer All of the basic inorganic layer and the upper inorganic layer may have different crystal structures. Here, the case where the crystal structures are different includes a case where the inorganic layers adjacent to each other have different compositions, or an inorganic layer having the same composition, but a case where it differs depending on the formation method or formation conditions.

It is preferable that any one of the basic inorganic layer and the upper inorganic layer is made of any one of a metal oxide, a metal nitride, and a metal oxynitride. As long as all of the basic inorganic layer and the upper inorganic layer are made of metal oxide, metal nitride, or metal oxynitride, other inorganic layers may be included. Further, the basic inorganic layer and the upper inorganic layer may be made of only one of metal oxide, metal nitride, and metal oxynitride, or metal oxide and metal nitride, metal nitride and metal oxynitride. Or two types of metal oxide, metal oxynitride, and three types of metal oxide, metal nitride, and metal oxynitride.

The three adjacent inorganic layers of the protective layer are preferably formed by laminating an aluminum oxide layer, a silicon oxide layer, and an aluminum oxide layer in this order.

The layer thickness of the protective layer is not more 50μm or less, moisture permeability of the protective layer is preferably less 0.07g / m ² / 24h at 40 ° C..

When the protective layer includes a substrate on which the basic inorganic layer is directly laid, the glass transition temperature (Tg) of the substrate is 85 ° C. or higher, more preferably 100 ° C. or higher. Is desirable. When the protective layer includes a plurality of substrates,
Desirably, the glass transition temperature of at least one of the plurality of substrates is 85 ° C. or higher, preferably 100 ° C. or higher, more preferably all the glass transition temperatures of the plurality of substrates are 85 ° C. As described above, it is desirable that the temperature is 100 ° C or higher.

The radiation image conversion panel of the present invention is a radiation image conversion panel having a stimulable phosphor layer and a protective layer, and the protective layer includes a basic inorganic layer and at least one upper inorganic layer located on the basic inorganic layer. Since each upper inorganic layer is directly laid on the inorganic layer located under each inorganic layer, a panel having extremely high moisture resistance and durability can be obtained. In addition, when the inorganic layers are bonded together with an adhesive, image unevenness due to the bonding state occurs, but the radiation image conversion panel of the present invention does not need to bond the inorganic layers with an adhesive, so it has high sensitivity. Good image quality can be obtained. Furthermore, since the entire protective layer can be formed thinner by directly laying the inorganic layer, high image quality can be realized.

In addition, the crystal | crystallization of at least 1 set of inorganic layers adjacent to each other by making the layer thickness of either upper inorganic layer thicker than the layer thickness of a basic inorganic layer, or a basic inorganic layer and an upper inorganic layer By making the structure different, the upper inorganic layer can more effectively compensate for crystal defects generated in the basic inorganic layer, so that further improvement in moisture resistance can be expected.

Further, in the case of a protective layer including a base material on which the basic inorganic layer is directly laid, by selecting a base material having a glass transition temperature of 85 ° C. or higher, and further 100 ° C. or higher, the inorganic layer is added to the base material. It is possible to further suppress a decrease in moisture resistance due to alteration of the base material when directly laid.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partial schematic cross-sectional view of a radiation image conversion panel showing a first embodiment of the present invention.

As shown in FIG. 1, the radiation image conversion panel 1 by 1st Embodiment has the fluorescent substance layer 2 and the protective layer 4 which consist of a stimulable fluorescent substance on the support body 3, and the protective layer 4 consists of The base inorganic layer 6 is provided on the substrate 5, and the first upper inorganic layer 7 and the second upper inorganic layer 8 are provided on the basic inorganic layer 6, and the radiation image conversion panel 1 includes the protective layer 4. The second upper inorganic layer 8 side and the phosphor layer 2 are bonded or adhesively laminated with an adhesive or the like. Although FIG. 1 shows a structure in which the upper inorganic layer is two layers, the upper inorganic layer may be one layer or more than that. However, from the viewpoint of manufacturing cost, it is preferable to manufacture with up to about 10 layers.

In FIG. 1, the basic inorganic layer 6, the first upper inorganic layer 7 and the second upper inorganic layer 8 are directly laid on the base material 5 to separately produce a protective layer, which is bonded to the phosphor layer. In this case, adhesion or decompression laminating with an agent or the like is shown, but without using the base material 5, the basic inorganic layer 6, the first upper inorganic layer 7 and the second upper inorganic layer 8 are formed on the phosphor layer 2. It is good also as a structure laid directly.

The layer thickness of either the first upper inorganic layer 7 or the second upper inorganic layer 8 or both the first upper inorganic layer 7 and the second upper inorganic layer 8 is greater than the layer thickness of the basic inorganic layer 6. It is also preferable that the thickness is thick. Moreover, the layer thickness of the upper inorganic layers 7 and / or 8 having a layer thickness larger than the layer thickness of the basic inorganic layer 6 is preferably in the range of 20 to 1000 nm, more preferably in the range of 30 to 500 nm. In addition, it is preferable that the dispersion | variation in the thickness of each inorganic layer is small. Furthermore, it is preferable that the basic inorganic layer 6 and the first upper inorganic layer 7 or the first upper inorganic layer 7 and the second upper inorganic layer 8 have different crystal structures.

2 to 4 are schematic cross-sectional views showing a more detailed embodiment of the protective layer. The numerical values in the figure indicate the respective layer thicknesses. Note that here, as examples in which the crystal structures are different, those having different layer compositions are given as examples. The protective layer shown in FIG. 2 has an aluminum oxide layer (basic inorganic layer), a silicon oxide layer (first upper inorganic layer), and an aluminum oxide layer (second upper inorganic layer) directly on PET as a base material. A fluorine hard coat layer is provided under the base material (on the uppermost side of the radiation image conversion panel) for improving scratch resistance. The thicknesses of the silicon oxide layer and the aluminum oxide layer as the second upper inorganic layer are both thicker than the aluminum oxide layer of the basic inorganic layer. In addition, although the structure which provided the hard-coat layer in FIG. 2 is shown, the antifouling layer for improving antifouling property may be provided. The surface of the protective layer may be AR-coated. Taking FIG. 2 as an example, the surface of the base material and the surface of the aluminum oxide layer, which is the second upper inorganic layer, reduce unnecessary reflected light. May be. The protective layer shown in FIG. 2 is laminated at a reduced pressure with the phosphor layer and the aluminum oxide layer surface, which is the second upper inorganic layer, facing each other.

The protective layer shown in FIG. 3 has a silicon oxide layer (basic inorganic layer), a silicon oxynitride layer (first upper inorganic layer), and an aluminum oxide layer (second upper inorganic layer) on PET as a base material. It is laid directly. Thus, the basic inorganic layer and the upper inorganic layer may all be composed of inorganic layers having different compositions. As shown in FIG. 3, the uppermost aluminum oxide layer may be laminated with the phosphor layer via a laminate layer and a PET layer.

The protective layer shown in FIG. 4 has an aluminum oxide layer (basic inorganic layer), a silicon oxide layer (first upper inorganic layer), and an aluminum oxide layer (second upper inorganic layer) directly on PET as a base material. Only the layer thickness of the silicon oxide layer, which is the first upper inorganic layer, is formed so as to be thicker than the layer thickness of the aluminum oxide layer, which is the basic inorganic layer. As described above, any of the plurality of upper inorganic layers may be thicker than the basic inorganic layer. Further, as shown in FIG. 4, a casting polypropylene (CPP) layer to which a filler additive for imparting appropriate haze is added is provided on the aluminum oxide layer which is the second upper inorganic layer. Also good. In this case, the haze value of the protective layer is preferably adjusted in the range of 3 to 70%.

The protective layer shown in FIGS. 2 to 4 shows a case where the second upper inorganic layer side is laminated with the phosphor layer, but as shown in FIG. It does not matter if it is laminated.

FIG. 6 is a partial schematic cross-sectional view of a radiation image conversion panel showing a second embodiment of the present invention. As shown in FIG. 6, the radiation image conversion panel 10 according to the second embodiment includes a phosphor layer 12 made of a stimulable phosphor and a protective layer 14 on a support 13, and the protective layer 14 includes A laminate a in which the basic inorganic layer 16a, the first upper inorganic layer 17a, and the second upper inorganic layer 18a are directly laid on the base material 15a, and the basic inorganic layer 16b, the first upper inorganic layer 18a on the base material 15b. The upper inorganic layer 17b and the second upper inorganic layer 18b are directly laminated, and the laminate b. The phosphor layer 12, the second upper inorganic layer 18a of the laminate a, and the base material 15a of the laminate a The second upper inorganic layer 18b of the laminate b is bonded or laminated under reduced pressure with an adhesive or the like. In FIG. 6, the stacked bodies to be stacked are stacked in the same stacking order, but conversely, that is, the base material 15 a of the stacked body a and the base material 15 b of the stacked body b are stacked to form the second upper inorganic layer. The layer 18b may be laminated so as to be the uppermost surface of the radiation image conversion panel 10. In addition, although the laminated body of the same structure is used in FIG. 6, the structure of a laminated body may differ.

7 to 9 are schematic sectional views showing a more detailed embodiment of the protective layer shown in FIG. In the protective layer shown in FIG. 7, an aluminum oxide layer (basic inorganic layer), a silicon oxide layer (first upper inorganic layer), and an aluminum oxide layer (second upper inorganic layer) are directly laid on the base PET. Two laminates thus obtained are bonded via a laminate layer. The protective layer shown in FIG. 7 has a structure in which the thickness of the silicon oxide layer that is the first upper inorganic layer of the two laminates is larger than the thickness of the aluminum oxide layer that is the basic inorganic layer. Only the layer thickness of the first upper inorganic layer of one of the laminates may be thicker than the layer thickness of the aluminum oxide layer that is the basic inorganic layer. Note that the laminate layer shown in FIG. 7 may include a filler added as shown in FIG. 8 or a colorant that has little influence on the wavelength of the stimulable light emission.

The order of the base material-aluminum oxide layer-silicon oxide layer-aluminum oxide layer may be in the order of base material-silicon oxide layer-aluminum oxide layer-silicon oxide layer as shown in FIG.

In the protective layer shown in FIG. 10, an organic primer layer is provided on a PET substrate, and an aluminum oxide layer (basic inorganic layer) and a silicon oxynitride layer (first upper inorganic layer) are directly laid thereon. Two laminated bodies are bonded through a laminate layer. Thus, it is good also as a structure which provided the organic primer layer between the base material and the basic inorganic layer. The organic primer layer here is laid as a layer only after being applied or vapor-deposited on a substrate. This is different from the above-mentioned laminate layer. By providing the organic primer layer, it is possible to further improve moisture resistance. In addition, although the organic primer layer is provided between the base material and the basic inorganic layer in FIG. 10, it may be provided at other positions, and also in the case of the protective layer shown in FIGS. 2 to 6. Can do.

Hereinafter, each layer will be described in detail.
The basic inorganic layer and the upper inorganic layer are preferably made of metal oxide, metal nitride, metal oxynitride, or the like. More specifically, the inorganic layer is preferably a transparent vapor deposition layer in which an inorganic substance having a gas barrier property and having no light absorption at a wavelength of 300 nm to 1000 nm is vapor-deposited. Preferred examples of the inorganic substance that does not absorb light at a wavelength of 300 nm to 1000 nm include silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, zirconium oxide, tin oxide, silicon oxynitride, and aluminum oxynitride. Aluminum oxide and silicon oxide may be vapor-deposited alone, but if both are vapor-deposited, the gas barrier property can be increased, so it is more preferable to vaporize both when aluminum oxide and silicon oxide are used. . Among these, aluminum oxide, silicon oxide, and silicon oxynitride are particularly preferable because they have high light transmittance and high gas barrier properties, that is, a dense film with few cracks and micropores can be formed.

The upper inorganic layer is laid directly on the inorganic layer located under each inorganic layer. On the other hand, the basic inorganic layer is not necessarily directly, but is preferably laid directly on a substrate or the like. As described above, the inorganic layer is formed by a dry process such as sputtering, a PVD method, a CVD method, or a wet process such as a sol-gel method, and is directly laid on the inorganic layer located below the inorganic layer. In any method, the transparency and barrier properties of the inorganic layer are not greatly changed, and can be appropriately selected. From the viewpoint of ease of formation and simplicity, the CVD method, particularly PE-CVD ( A method such as Plasma enhanced CVD or ECR-PE-CVD is preferred.

For the base material, materials made of materials such as PET, polycycloolefin, PEN (polyethylene naphthalate), PVA (polyvinyl alcohol), nanoalloy polymer of PET and PEI (polyetherimide), and transparent aramid are preferably used. . In particular, it is desirable that the substrate has a glass transition temperature (Tg) of 85 ° C. or higher, preferably 100 ° C. or higher. Polycycloolefin having a glass transition temperature of 85 ° C. or higher, PEN (polyethylene naphthalate), PVA (polyvinyl) Alcohol), PET and PEI (polyetherimide) nanoalloy polymer, and transparent aramid are preferred. Furthermore, what consists of materials, such as a polycycloolefin which has a glass transition temperature of 100 degreeC or more, PEN (polyethylene naphthalate), a nanoalloy polymer of PET and PEI (polyetherimide), a transparent aramid, is more preferable.

Below, the material used suitably as PET and a base material, and its glass transition temperature are shown.

As shown in FIG. 6, in the case of a protective layer comprising two substrates directly laid with a basic inorganic layer, the glass transition temperature of at least one substrate is 85 ° C. or higher, preferably 100 ° C. or higher. More preferably, it is desirable that the two substrates have a glass transition temperature of 85 ° C. or higher, more preferably 100 ° C. or higher.

The organic primer layer may be, for example, a cellulose derivative such as cellulose acetate or nitrocellulose; or polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyvinyl acetate, vinyl chloride / vinyl acetate copolymer, fluororesin, polyethylene, polypropylene, polyester Transparent polymer materials such as synthetic polymer materials such as acrylic, polyparaxylylene, PET, hydrochloric acid rubber, and vinylidene chloride copolymer can be used. These synthetic polymer materials forming the organic primer layer may be used as a polymer or a monomer, but are preferably those that are crosslinked by irradiation with heat, visible light, UV light, electron beam, or the like. .

Further, when the organic primer layer is provided on the substrate, it is preferable to add a coupling agent such as a silane coupling agent or a titanate coupling agent in order to improve the adhesion with the substrate. Furthermore, various polymers and monomers having a hydroxyl group, pigments, dyes, etc., for the purpose of improving the coating properties, vapor deposition properties and properties of the thin film after curing, and imparting photosensitivity to the coating film, etc. Colorants, anti-yellowing agents, stabilizers such as anti-aging agents and UV absorbers, thermal acid generators, photosensitive acid generators, surfactants, solvents, cross-linking agents, hardeners, polymerization inhibitors, etc. These various additives can be contained depending on the purpose.

Also, the organic primer layer may contain organic or inorganic powders in order to improve durability and prevent nitrite. When contained, it is more preferably about 0.5 to 60% by weight per weight of the organic primer layer. The powder preferably has absorption in a specific band, for example, ultramarine blue or the like, or white powder that does not exhibit specific absorption in the wavelength range of 300 to 900 nm. The average particle size of these powders is preferably about 0.01 to 10 μm, more preferably about 0.3 to 3 μm. In general, the particle size of these particles has a distribution, but a narrow distribution is preferable. The same applies when the laminate layer contains organic or inorganic powder.

The organic primer layer may be formed by either coating method or vapor deposition method, but the vapor deposition method is preferable because the surface can be formed more smoothly.

The protective layer can be formed by adhering the base material side or the upper inorganic layer side with an adhesive on the phosphor layer in a dry atmosphere, or by vacuum lamination. In any case, it is more preferable to carry out by reduced pressure sealing. By doing so, it is possible to suppress peeling between the phosphor layer and the base material or the upper inorganic layer, particularly in a state where the atmospheric pressure is low.

The adhesive that can be used for adhesion between the phosphor layer and the protective layer and between the laminates is not particularly limited, and is frequently used for dry lamination, etc., vinyl-based, acrylic-based, polyamide Various adhesives such as epoxy, rubber, urethane, etc. can be used.

Also, in order to sufficiently prevent moisture absorption from the side surface of the phosphor layer, it is preferable to seal the side surface of the radiation image conversion panel with glass, epoxy resin, UV curable resin, metal (solder), or the like. In order to prevent performance degradation due to moisture absorption of the phosphor layer, the removal from the vapor deposition tank (vapor deposition machine) to the sealing of the end face should be performed in vacuum or dry air, inert gas, or hydrophobic inert gas. Is preferred.

Examples of stimulable phosphors used in the radiation image conversion panel of the present invention include:
Stimulable phosphors represented by the general formula (M _1-f · M _f ^I ) X · bM ^III X3 ″: cA (I) described in JP-B-7-84588 are preferable. the M ^I in the formula (I) from the viewpoint of brightness, Rb, Na containing the Cs and / or Cs, the K is preferably at least one alkali metal is particularly selected from Rb and Cs as the preferred .M ^III Is preferably at least one trivalent metal selected from Y, La, Lu, Al, Ga and In. X ″ is preferably at least one halogen selected from F, Cl and Br. The b value representing the content of M ^III X3 ″ is preferably selected from the range of 0 ≦ b ≦ 10 ⁻² .

In the general formula (I), the activator A is preferably at least one metal selected from Eu, Tb, Ce, Tm, Dy, Ho, Gd, Sm, Tl and Na, particularly Eu, Ce, Sm, Tl and At least one metal selected from Na is preferred. Further, the C value representing the amount of the activator is preferably selected from the range of 10 ⁻⁶ <C <0.1 from the viewpoint of stimulated emission luminance.

Furthermore, the following photostimulable phosphors can also be used.
U.S. patents listed in the 3,859,527 Pat SrS: Ce, Sm, SrS: Eu, Sm, ThO 2: Er, and _{La 2 O 2 S: Eu,} Sm,

ZnS: Cu, Pb, BaO.xAl ₂ O ₃ : Eu (provided that 0.8 ≦ x ≦ 10) described in JP-A-55-12142, and M ^II O · xSiO ₂ : A (provided that M ^II is Mg, Ca, Sr, Zn, Cd, or Ba, A is Ce, Tb, Eu, Tm, Pb, Tl, Bi, or Mn, and x is 0.5 ≦ x ≦ 2.5),

(Ba _1-Xy , Mg _X , Ca _y ) FX: aEu ²⁺ described in JP _-A- 55-12143 (where X is at least one of Cl and Br, and x and y are 0 <x + y ≦ 0.6 and xy ≠ 0, and a is 10 ⁻⁶ ≦ a ≦ 5 × 10 ⁻² ),

LnOX: xA described in JP-A-55-12144 (where Ln is at least one of La, Y, Gd, and Lu, X is at least one of Cl and Br, and A is Ce and Tb) At least one of x and x is 0 <x <0.1),

(Ba _1-X , M ²⁺ _X ) FX: yA (where M ²⁺ is at least one of Mg, Ca, Sr, Zn, and Cd, X Is at least one of Cl, Br and I, A is at least one of Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb and Er, and x is 0 ≦ x ≦ 0.6, y is 0 ≦ y ≦ 0.2),

M ^II FX · xA: yLn described in JP-A-55-160078 (where M ^II is at least one of Ba, Ca, Sr, Mg, Zn and Cd, and A is BeO, MgO, CaO, SrO, BaO, ZnO, Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , GeO ₂ , SnO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ And at least one of ThO ₂ , Ln is at least one of Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Sm and Gd, X is Cl, Br and I At least one kind, and x and y are 5 × 10 ⁻⁵ ≦ x ≦ 0.5 and 0 <y ≦ 0.2, respectively,

(Ba _1-X , M ^II _X ) F ₂ · aBaX ₂ : yEu, zA described in JP-A-56-116777 (where M ^II is one of beryllium, magnesium, calcium, strontium, zinc and cadmium) X is at least one of chlorine, bromine and iodine, A is at least one of zirconium and scandium, and a, x, y and z are 0.5 ≦ a ≦ 1.25 and 0 ≦ x ≦, respectively. 1, 10 ⁻⁶ ≦ y ≦ 2 × 10 ⁻¹ , and 0 <z ≦ 10 ⁻² ).

(Ba _1-X , M ^II _X ) F ₂ · aBaX ₂ : yEu, zB described in JP _-A- 57-23673 (where M ^II is beryllium, magnesium, calcium, strontium, zinc and cadmium) X is at least one of chlorine, bromine and iodine, and a, x, y and z are 0.5 ≦ a ≦ 1.25, 0 ≦ x ≦ 1, 10 ⁻⁶ ≦ y ≦ 2 × 10, respectively. ^-1 and 0 <z ≦ 10 ⁻² ),

(Ba _1-X , M ^II _X ) F ₂ · aBaX ₂ : yEu, zA described in JP-A-57-23675 (where M ^II is beryllium, magnesium, calcium, strontium, zinc and cadmium) X is at least one of chlorine, bromine and iodine, A is at least one of arsenic and silicon, and a, x, y and z are 0.5 ≦ a ≦ 1.25 and 0 ≦ x ≦, respectively. 1, 10 ⁻⁶ ≦ y ≦ 2 × 10 ⁻¹ , and 0 <z ≦ 5 × 10 ⁻¹ ),

M ^III OX: xCe described in JP-A-58-69281 (where M ^III is selected from the group consisting of Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Bi) A phosphor represented by a composition formula of at least one trivalent metal selected, wherein X is one or both of Cl and Br, and x is 0 <x <0.1),

Ba _1-X M _{X / 2} L _{X / 2} FX: yEu ²⁺ described in JP _-A- 58-206678 (where M is at least selected from the group consisting of Li, Na, K, Rb and Cs) L represents Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, In and Tl X represents at least one trivalent metal selected from the group consisting of Cl, Br and I; and x represents 10 ⁻² ≦ x ≦ 0.5, and y represents 0 A phosphor represented by a composition formula of <y ≦ 0.1.

BaFX · xA: yEu ²⁺ described in JP-A-59-27980 (where X is at least one halogen selected from the group consisting of Cl, Br and I; A is a calcined tetrafluoroborate compound) And x is 10 ⁻⁶ ≦ x ≦ 0.1, y is 0 <y ≦ 0.1),

BaFX · xA: yEu ²⁺ described in JP-A-59-47289 (where X is at least one halogen selected from the group consisting of Cl, Br and I; A is hexafluorosilicic acid) , Calcined product of at least one compound selected from the group of hexafluoro compounds consisting of monovalent or divalent metal salts of hexafluorotitanic acid and hexafluorozirconic acid; and x is 10 ⁻⁶ ≦ x ≦ 0.1, y is a phosphor represented by a composition formula of 0 <y ≦ 0.1,

BaFX.xNaX ′: aEu ²⁺ described in JP-A-59-56479 (where X and X ′ are each at least one of Cl, Br, and I, and x and a are each 0 <X ≦ 2 and 0 <a ≦ 0.2))

M ^II FX · xNaX ′: yEu ²⁺ : zA described in JP-A-59-56480 (where M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca) X and X ′ are each at least one halogen selected from the group consisting of Cl, Br and I; and A is at least one transition metal selected from V, Cr, Mn, Fe, Co and Ni. And x is 0 <x ≦ 2, y is 0 <y ≦ 0.2, and z is 0 <z ≦ 10 ⁻² ),

M ^II FX, aM ^I X ′, bM ′ ^II X ″ ₂ , cM ^III X ₃ , xA: yEu ^{2+ described in} JP-A-59-75200 (However, M ^II is derived from Ba, Sr and Ca. At least one alkaline earth metal selected from the group consisting of; M ^I is at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs; M ′ ^II consists of Be and Mg is at least one trivalent metal selected from the group; M ^III is Al, Ga, is at least one trivalent metal selected from the group consisting of in and Tl; a is a metal oxide; X is Cl, And at least one halogen selected from the group consisting of Br and I; X ′, X ″ and X are at least one halogen selected from the group consisting of F, Cl, Br and I; ≦ a ≦ 2, b is 0 ≦ b ≦ 10 ⁻² , c is 0 ≦ c ≦ 10 ⁻² , and a + b + c ≧ 10 ⁻⁶ ; x is 0 <x ≦ 0.5, y is 0 < a phosphor represented by a composition formula of y ≦ 0.2),

M ^II X ₂ · aM ^II X ′ ₂ : xEu ²⁺ described in JP-A-60-84381 (where M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca) X and X ′ are at least one halogen selected from the group consisting of Cl, Br and I, and X ≠ X ′; and a is 0.1 ≦ a ≦ 10.0, x is 0 <x ≦ 0.2) and a stimulable phosphor represented by a composition formula of

M ^II FX and aM ^I X ′: xEu ²⁺ described in JP-A-60-101173 (where M ^{II is} at least one alkaline earth metal selected from the group consisting ^of Ba, Sr and Ca) M ^I is at least one alkali metal selected from the group consisting of Rb and Cs; X is at least one halogen selected from the group consisting of Cl, Br and I; X ′ is F, Cl, Br and A photostimulable phosphor represented by a composition formula: at least one halogen selected from the group consisting of I; and a and x are 0 ≦ a ≦ 4.0 and 0 <x ≦ 0.2, respectively.

M ^I X: xBi described in JP-A-62-25189 (where M ^I is at least one alkali metal selected from the group consisting of Rb and Cs; X is a group consisting of Cl, Br and I) A photostimulable phosphor represented by a composition formula: at least one halogen selected from x; and x is a numerical value in the range of 0 <x ≦ 0.2.

LnOX: xCe described in JP-A-2-229882 (where Ln is at least one of La, Y, Gd and Lu, X is at least one of Cl, Br and I, and x is 0 <x Cerium-activated rare earth oxyhalogen, wherein the ratio of Ln to X is 0.500 <X / Ln ≦ 0.998, and the maximum wavelength λ of the stimulable excitation spectrum is 550 nm <λ <700 nm) Fluoride,
Etc.

Further, the M ^II X ₂ · aM ^II X ′ ₂ : xEu ²⁺ stimulable phosphor described in JP-A-60-84381 has the following additives as M ^II X ₂ · aM ^II X ′ ₂ may be contained in the following ratio per mole.

BM ^I X ″ described in JP-A-60-166379 (where M ^I is at least one alkali metal selected from the group consisting of Rb and Cs, and X ″ is selected from F, Cl, Br and I). BKX ″ · cMgX ₂ · dM ^III X ′ ₃ described in JP-A-60-221483 (provided that at least one halogen selected from the group consisting of b and 0 <b ≦ 10.0); M ^III is at least one trivalent metal selected from the group consisting of Sc, Y, La, Gd and Lu, and X ″, X and X ′ are all selected from the group consisting of F, Cl, Br and I. At least one halogen, and b, c and d are 0 ≦ b ≦ 2.0, 0 ≦ c ≦ 2.0, 0 ≦ d ≦ 2.0 and 2 × 10 ⁻⁵ ≦ b + c + d, respectively. YB described in JP-A-60-228592 (where y is 2 × 10 ⁻⁴ ≦ y ≦ 2 × 10 ⁻¹ ); described in JP-A-60-228593 bA A is at least one oxide selected from the group consisting of SiO ₂ and P ₂ O ₅ , and b is 10 ⁻⁴ ≦ b ≦ 2 × 10 ⁻¹ ); BSiO (where b is 0 <b ≦ 3 × 10 ⁻² ); bSnX ″ ₂ (where X ″ is F, Cl, Br) described in JP-A-61-120885 And at least one halogen selected from the group consisting of I and I, and b is 0 <b ≦ 10 ⁻³ ); bCsX ″ · cSnX ₂ (excluding X ″ And X are each at least one halogen selected from the group consisting of F, Cl, Br and I, and b and c are 0 <b ≦ 10.0 and 10 ⁻⁶ ≦ c ≦ 2 × 10 ⁻² , respectively. there); and are bCsX "· yLn ³⁺ (However, X" which is described in JP-a No. 61-235487 is F, Cl, halogenated der least one selected from the group consisting of Br and I , Ln is at least one rare earth element selected from the group consisting of Sc, Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and b and y are respectively 0 <b ≦ 10.0 and 10 ⁻⁶ ≦ y ≦ 1.8 × 10 ⁻¹ ).

Among the photostimulable phosphors described above, divalent europium activated alkaline earth metal fluorohalide phosphors (eg BaFI: Eu) europium activated alkali metal halide phosphors (eg CsBr: Eu), iodine The divalent europium activated alkaline earth metal halide phosphor containing iodine, the rare earth element activated rare earth oxyhalide phosphor containing iodine, and the bismuth activated alkali metal halide phosphor containing iodine have high brightness. Since these phosphors can be made into needle-like crystals, the hygroscopic property is likely to be a problem. Therefore, the use of the protective layer of the present invention can effectively prevent moisture. Can be achieved.

The phosphor layer can be formed on the support by a known method such as vapor deposition, sputtering, or coating. In the vapor deposition method, a support is first installed in a vapor deposition apparatus, and then the interior of the apparatus is evacuated to a vacuum of about 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, so that the photostimulable phosphor is deposited on the support surface to a desired thickness. It is also possible to form the photostimulable phosphor layer by dividing the vapor deposition process into a plurality of times. Further, in the vapor deposition step, the photostimulable phosphor layer can be formed at the same time as the desired photostimulable phosphor is synthesized on the support by co-evaporation using a plurality of resistance heaters or electron beams. After the vapor deposition, the photostimulable phosphor layer may be heat-treated.

In the sputtering method, as in the vapor deposition method, after the support is placed in the sputtering apparatus, the inside of the apparatus is once evacuated to a vacuum of about 10 ⁻⁴ Pa, and then inert gases such as Ar and Ne are used as sputtering gases. A gas is introduced into the sputtering apparatus to obtain a gas pressure of about 10 ⁻¹ Pa. Next, the photostimulable phosphor is deposited in a desired thickness on the surface of the protective layer by sputtering using the photostimulable phosphor as a target. In the sputtering process, as in the vapor deposition method, it is possible to form the photostimulable phosphor layer by dividing it into a plurality of times, and using a plurality of targets each made of different photostimulable phosphors, It is also possible to form the photostimulable phosphor layer by sputtering the target simultaneously or sequentially. In the sputtering method, reactive sputtering may be performed by introducing a gas such as O ₂ , H _2, or halogen as necessary. After completion of sputtering, the photostimulable phosphor layer may be heat-treated.

In the coating method, the phosphor is thoroughly mixed with a solvent to prepare a coating solution in which the stimulable phosphor is uniformly dispersed in the binder solution, and this coating solution is uniformly applied to the surface of the support. To form a coating film. This coating operation can be performed by using a normal coating means, for example, a doctor blade, a roll coater, a knife coater or the like.

The layer thickness of the phosphor layer varies depending on the characteristics of the intended radiation image conversion panel, the type of phosphor, the mixing ratio of the binder and the phosphor, and is generally about 20 μm to 1 mm. More preferably, the thickness is 50 μm to 500 μm.

The support can be arbitrarily selected from materials known as a support for conventional radiation image conversion panels. Further, in order to enhance the bonding between the support and the phosphor layer, or to improve the sensitivity or image quality (sharpness, graininess) as a radiation image conversion panel, the support surface on the side where the phosphor layer is provided is provided. Apply a polymer substance such as gelatin to form an adhesion-imparting layer, or provide a light reflecting layer made of a light reflecting substance such as titanium dioxide, or a light absorbing layer made of a light absorbing substance such as carbon black. However, these various layers can also be provided for the support used in the present invention. These configurations can be arbitrarily selected according to the purpose and application of the desired radiation image conversion panel.

Further, as described in JP-A-58-200200, for the purpose of improving the sharpness of the obtained image, the surface of the support on the phosphor layer side (adhesiveness to the surface of the support on the phosphor layer side) When an application layer, a light reflection layer, a light absorption layer, or the like is provided, it means that the surface thereof is finely uneven.
Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1
<Preparation of protective layer>
After mounting a PET film with a thickness of 12 μm as a base film on a supply roll of a vacuum deposition apparatus, an aluminum oxide layer is formed on the PET as a basic inorganic layer by plasma CVD while the base film is transported at a constant speed. Was vacuum deposited to a thickness of 10 mm. Then, the silicon oxide layer (240 nm thickness) of the 1st upper inorganic layer was formed by forming into a film, supplying oxygen with the plasma CVD method using the organosilicon compound (hexamethyldisiloxane). Further, on this silicon oxide layer, aluminum oxide is vacuum-deposited to a thickness of 10 mm by a plasma CVD method, an aluminum oxide layer is formed as a second upper inorganic layer, and an aluminum oxide layer-silicon oxide layer-aluminum oxide layer inorganic layer A transparent moisture-proof film consisting of three layers was produced. These inorganic layers were laid in the process of conveying a long base film once at a constant speed. The variation of the thickness of each inorganic layer was ± 30% or less, and carbon was uniformly distributed in the thickness direction by ESCA analysis (approximately 18% in terms of the number of atoms). Thereafter, the two moisture-proof films are bonded in the same direction (with one surface side being an inorganic layer surface) through a 2.5 μm-thick polyester resin layer, and a 530 mm square 27 μm thick transparent protective layer (protective layer) Was obtained as shown in FIG.

<Adhesion between protective layer and glass sealing frame>
A soda glass sealing frame (vertical, horizontal 450 mm square, thickness 0.5 mm, width 6 mm, inner corner portion R = 2 mmφ) and the inorganic layer surface of the protective layer prepared above are two-component curable epoxy resin (XB5047, XB5067: manufactured by Bantico Co., Ltd.). At this time, the center of the sealing frame and the center of the protective layer are overlapped, adhered on the surface of the protective layer in contact with the frame surface, cured at 40 ° C. for one day, and the bonded body of the protective layer and the glass sealing frame; did.

<Preparation of photostimulable phosphor layer>
The substrate has a vertical, horizontal 450mm square, 5mmφ decompression hole as a substrate at the corner of a distance of 11mm from two adjacent sides to the hole center, and an Al vapor deposition reflective layer is laid on one side except for the edge (edge width 8mm). An 8 mm thick soda glass plate was prepared. A mask was placed in a portion from the peripheral edge on the reflective layer surface to 8 mm and the decompression hole portion, and was placed in a vapor deposition machine so as to be deposited on the reflective layer surface where the mask was not placed. Then place the EuBr _m tablet and CsBr tablet in place, and a vacuum degree of 1.0Pa and evacuated deposition machine. Subsequently, the substrate was heated to 100 ° C. with a heater. Thereafter, the EuBr _m tablets and CsBr tablet in a platinum boat and heated, a stimulable phosphor on a surface on the substrate excluding the mask portion (CsBr: Eu) was allowed to 500μm deposited. Under a dry atmosphere, the inside of the vapor deposition machine was returned to atmospheric pressure and the substrate was taken out. On the substrate, needle-like photostimulable phosphors having a thickness of about 8 μm were erected with a slight gap therebetween in the direction perpendicular to the substrate.

<Sealing of stimulable phosphor>
An Al-deposited reflective layer laying soda glass support on which a CsBr: Eu photostimulable phosphor is formed by vapor deposition except for the bonded portion (8 mm from the periphery) and the decompression hole, and a sealing frame, prepared as described above. The bonded transparent protective layer was adhered using an adhesive (SU2153-9: manufactured by Suncorek) while applying pressure, and cured at room temperature (25 ° C.) for 12 hours. Further, EDPM rubber was embedded in the decompression hole and adhered with an adhesive (SU2153-9) to seal the decompression hole. As a result, a structure in which the vapor-deposited photostimulable phosphor layer was sealed by the support, the sealing frame, and the protective layer was formed.

<Pressure reduction, glass plug sealing>
An injection needle was pierced through the sealing hole EDPM rubber of the above-mentioned sealed structure, and the internal gas was extracted by a vacuum pump to obtain a reduced pressure state. Then, the radiation image conversion panel was made into a completely sealed structure by plugging with a glass stopper with an adhesive (SU2153-9) attached on the EDPM rubber in the decompression hole.

(Example 2)
The metal aluminum in the crucible is irradiated with an electron beam, heated and evaporated, and a mixed gas of oxygen and helium is introduced through a gas introduction pipe, whereby an aluminum oxide layer having a thickness of 10 nm is formed as a basic inorganic layer on the substrate. Laid. After laying the aluminum oxide layer, an initial vacuum degree of 3 × 10 ⁻⁴ Pa was drawn by a DC magnetron method, and a mixed gas of oxygen / argon gas 9% was introduced here, and the first condition was obtained under the condition of 3 × 10 ⁻¹ Pa. A silicon oxide layer having a thickness of 240 nm was laid as the upper inorganic layer. Subsequently, after laying the silicon oxide layer, an aluminum oxide layer (thickness 10 nm) was provided as the second upper inorganic layer in the same manner as the basic inorganic layer. Other than this, a protective layer was formed as described in Example 1 to obtain a transparent protective layer having a thickness of 27 μm (the structure of the protective layer is shown in FIG. 7). The adhesion of the protective layer and the glass sealing frame other than the above, the production of the stimulable phosphor layer, the sealing of the stimulable phosphor, the decompression, and the glass plug sealing were all carried out in the same manner as in Example 1 to obtain a radiation image. A conversion panel was prepared.

(Example 3)
An organic primer layer having a thickness of 1.5 μm was laid on the PET surface having a thickness of 12 μm, and an aluminum oxide layer was formed thereon as a basic inorganic layer in the same manner as in Example 1, and a silicon oxide layer was formed as the first upper inorganic layer. Instead, a silicon oxynitride layer was laid by the CVD method (the second upper inorganic layer was not formed) to obtain a 29 μm-thick transparent protective layer (the structure of the protective layer is shown in FIG. 10). The adhesion of the protective layer and the glass sealing frame other than the above, the production of the stimulable phosphor layer, the sealing of the stimulable phosphor, the decompression, and the glass plug sealing were all carried out in the same manner as in Example 1 to obtain a radiation image. A conversion panel was prepared.

Example 4
A moisture-proof film was produced in the same manner as in Example 1. The surface of the moisture-proof film on the side where the inorganic layer is laid and CPP 30 μm to which filler is added are dry-laminated with a polyurethane adhesive (adhesion thickness 3 μm), and a transparent protective layer having a thickness of 45 μm (the structure of the protective layer is shown in FIG. 4). Obtained). Moreover, it produced similarly to Example 1 except having produced the photostimulable fluorescent substance layer using the 2 mm thickness board | substrate with a 43 cm x 43 cm square without a decompression hole. The phosphor layer is sandwiched between the protective layer and the opaque sealing film (the CPP 30 μm / aluminum film 9 μm / PET 188 μm film dry-laminated film) so that the phosphor layer is on the protective layer side, and the pressure is reduced. A radiation image conversion panel was prepared by fusing and sealing the peripheral edge using an impulse sealer (3 mm heater).

(Example 5)
2000 ml of an aqueous BaI solution (3.5 N) and 100 ml of an aqueous EuBr ₃ solution (0.2 N) were placed in a reaction vessel, and the mother liquor was kept at 82 ° C. while stirring. 200 ml of an ammonium fluoride solution (8N) was injected into the reaction mother liquor using a pump to produce a precipitate. After aging for 2 hours, the precipitate was filtered, washed with methanol and dried to obtain BaFI crystals. This was mixed with alumina ultrafine particles uniformly, then filled in a quartz board, and fired at 825 ° C. for 1.5 hours in a hydrogen gas atmosphere using a tube furnace, and europium activated BFI phosphor particles were obtained. Obtained. Subsequently, the BFI phosphor particles were classified to obtain particles having an average particle diameter of 3 μm.

The phosphor layer is added to 300 g of europium-activated BFI phosphor particles obtained above, 11 g of polyurethane resin, and 1/4 g of bisphenol-type epoxy resin in a methyl ethyl ketone-toluene mixed solvent, and dispersed by a propeller mixer to obtain a viscosity of 25 to 25. A coating solution of 30 ps was prepared. This coating solution was applied onto a PET film with an undercoat layer by the doctor blade method, and then dried at 100 ° C. for 15 minutes to form a phosphor layer having a thickness of 280 μm. A radiation image conversion panel was produced in the same manner as in Example 1 except that this phosphor layer was cut into a 45 cm × 45 cm square and used.

(Example 6)
A silicon oxide layer was laid as a basic inorganic layer on PET having a thickness of 12 μm to a thickness of 10 nm by electron beam evaporation. After laying the silicon oxide layer, an aluminum oxide layer having a thickness of 200 nm was laid as the first upper inorganic layer by the same electron beam evaporation method. Further, after the aluminum oxide layer was laid, a silicon oxide layer having a thickness of 10 nm was laid as the second upper inorganic layer by the same electron beam evaporation method. Thereafter, in the same manner as in Example 1, a transparent protective layer having a thickness of 27 μm (the structure of the protective layer is as shown in FIG. 9) was obtained. The adhesion of the protective layer and the glass sealing frame other than the above, the production of the stimulable phosphor layer, the sealing of the stimulable phosphor, the decompression, and the glass plug sealing were all carried out in the same manner as in Example 1 to obtain a radiation image. A conversion panel was prepared.

(Example 7)
An aluminum oxide layer was laid as a basic inorganic layer on PET having a thickness of 12 μm to a thickness of 20 nm by sputtering. After laying the aluminum oxide layer, a silicon oxide layer having a thickness of 220 nm was laid as the first upper inorganic layer by the sputtering method. Further, after laying the silicon oxide, an aluminum oxide layer having a thickness of 30 nm was laid as the second upper inorganic layer by the sputtering method. Thereafter, in the same manner as in Example 1, a 29 μm thick transparent protective layer (the structure of the protective layer is as shown in FIG. 7) was obtained. The adhesion of the protective layer and the glass sealing frame other than the above, the production of the stimulable phosphor layer, the sealing of the stimulable phosphor, the decompression, and the glass plug sealing were all carried out in the same manner as in Example 1 to obtain a radiation image. A conversion panel was prepared.

(Example 8)
As the first upper inorganic layer, radiation was applied in the same manner as in Example 1 except that a silicon oxide layer having a thickness of 350 mm was formed by applying and curing a solution containing tetraalkoxylane as a main component by the wire bar coating method. An image conversion panel was prepared.

Example 9
A radiation image conversion panel was prepared in the same manner as in Example 8 except that polycycloolefin (Tg = 120 ° C.) having a thickness of 20 μm was used instead of PET as the base film.

(Example 10)
A radiation image conversion panel was prepared in the same manner as in Example 1 except that a film having a single glass transition temperature (Tg = 115 ° C.) made of a nanoalloy polymer of PET and PEI was used as the base film instead of PET. did.

(Example 11)
A radiation image conversion panel was prepared in the same manner as in Example 8 except that a transparent aramid film (Tg = 230 ° C.) having a thickness of 12 μm was used instead of PET as the base film.

(Comparative Example 1)
A silicon oxide layer having a thickness of 200 nm was formed as a transparent inorganic layer on 12 μm PET by electron beam evaporation to form a moisture-proof film. A radiation image conversion panel was prepared in the same manner as in Example 1 except that four sheets were laminated in the same direction and each was laminated with a 3 μm transparent polyurethane resin to prepare a protective layer.

(Comparative Example 2)
A silicon oxide layer having a thickness of 300 nm was formed as a transparent inorganic layer on 12 μm PET by a plasma CVD method to obtain a moisture-proof film. A radiation image conversion panel was produced in the same manner as in Example 1 except that this was used as a protective layer.

(Evaluation methods)
The results of evaluation in the thickness of the radiation image conversion panels prepared in Examples 1 to 7 and Comparative Examples 1 and 2, the moisture permeability of the protective layer at room temperature of 40 ° C. and 90% of humidity, the sharpness, and the rate of decrease in stimulated emission light Is shown in Table 1. In addition, the sharpness and the stimulated emission light reduction rate are measured by the following methods.

<Sharpness>
After irradiating the radiation image conversion panel with X-rays with a tube voltage of 80 kVp, the phosphor is excited by scanning at a wavelength of 650 nm, and the stimulated luminescence emitted from the phosphor layer is received and converted into an electrical signal. Was reproduced as an image by the image reproducing device to obtain an image on the display device. This was analyzed by a computer to obtain a modulation transfer function (MTF) (spatial frequency: 2 cycles / mm) of the obtained image. A higher MTF value indicates better sharpness.

<Stimulated light emission reduction rate>
The radiation image conversion panel is irradiated with X-rays, and the line sensor is irradiated with linear excitation light from the protective layer side. The detected amount of the photostimulated luminescence detected at that time is set as an initial value. This was aged for 30 days in a constant temperature chamber at 55 ° C. and 95%, and the stimulated emission light (post-thermo value) was measured again, and the reduction rate of the stimulated emission light was calculated by the following formula.
Stimulated emission light reduction rate (%) = {(initial value−post-thermo value) / initial value} × 100
The results are shown in Table 2.

As is clear from Table 2, the radiation image conversion panels shown in Examples 1 to 11 include a basic inorganic layer and at least one upper inorganic layer positioned on the basic inorganic layer, and each upper inorganic layer. Since the layers were directly laid on the inorganic layers located under the respective inorganic layers, the moisture permeability could be reduced as compared with Comparative Examples 1 and 2 having no such configuration.

In addition, the radiation image conversion panels of Example 9 and Example 11 in which the base film in Example 8 was replaced with a base film having a glass transition temperature of 100 ° C. or higher than the radiation image conversion panel of Example 8 were used. The moisture permeability was low, and the reduction rate of the photostimulated luminescence was low. Furthermore, the radiation image conversion panel of Example 10 in which the base film in Example 1 is replaced with a base film having a glass transition temperature of 100 ° C. or higher is lower in moisture permeability than the radiation image conversion panel of Example 1. The decrease rate of the photostimulated luminescence was low. This is because when a substrate having a high glass transition temperature is used, the substrate is less deteriorated even at a high temperature during vapor deposition and the like, and high moisture resistance is maintained. It is thought that it was suppressed more.

As described above, in the radiation image conversion panel according to the present invention, the protective layer includes a basic inorganic layer and at least one upper inorganic layer positioned on the basic inorganic layer, and each upper inorganic layer is below each inorganic layer. Since it is directly laid on the positioned inorganic layer, the moisture permeability can be lowered. Further, by using a base material having a high glass transition temperature as the base material that supports the inorganic layer of the protective layer, the moisture permeability can be further reduced. As a result, the radiation image conversion panel of the present invention was able to have high image quality and high durability with high sharpness and suppressed reduction of the stimulated emission light.

Schematic sectional view of a radiation image conversion panel showing a first embodiment of the present invention Schematic sectional view showing an embodiment of a protective layer of the radiation image conversion panel shown in FIG. Schematic sectional view showing another embodiment of the protective layer Schematic cross-sectional view showing still another embodiment of the protective layer Schematic cross-sectional view showing still another embodiment of the protective layer Schematic sectional view of a radiation image conversion panel showing a second embodiment of the present invention Schematic sectional view showing an embodiment of a protective layer of the radiation image conversion panel shown in FIG. Schematic sectional view showing another embodiment of the protective layer Schematic sectional view showing still another embodiment of the protective layer Schematic cross-sectional view showing still another embodiment of the protective layer

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radiation image conversion panel 2 Phosphor layer 3 Support body 4 Protective layer 5 Base material 6 Basic inorganic layer 7 First upper inorganic layer 8 Second upper inorganic layer

Claims (9)

In the radiation image conversion panel having a stimulable phosphor layer and a protective layer, the protective layer includes a basic inorganic layer and at least one upper inorganic layer located on the basic inorganic layer, and each upper inorganic layer is respectively A radiation image conversion panel, wherein the radiation image conversion panel is directly laid on an inorganic layer located under the inorganic layer. The radiation image conversion panel according to claim 1, wherein any one of the upper inorganic layers is thicker than the basic inorganic layer. 3. The radiation image conversion panel according to claim 2, wherein the layer thickness of the upper inorganic layer having a layer thickness larger than the layer thickness of the basic inorganic layer is in the range of 20 to 1000 nm. 4. The radiation image conversion panel according to claim 1, wherein at least one pair of inorganic layers adjacent to each other among the basic inorganic layer and the upper inorganic layer has a different crystal structure. . 5. The device according to claim 1, wherein one of the basic inorganic layer and the upper inorganic layer is made of any one of a metal oxide, a metal nitride, and a metal oxynitride. Radiation image conversion panel. 6. The radiation image conversion panel according to claim 5, wherein the three inorganic layers adjacent to each other of the protective layer are formed by laminating an aluminum oxide layer, a silicon oxide layer, and an aluminum oxide layer in this order. Wherein A is the layer thickness of the protective layer is 50μm or less, moisture permeability of the protective layer ^{is, 40 ℃ 0.07g / m 2 /} 24h claim 1, wherein the less is claimed 6 any one in Radiation image conversion panel. The said protective layer contains the base material by which the said basic inorganic layer was laid directly, The glass transition temperature (Tg) of this base material is 85 degreeC or more, The any one of Claim 1 to 7 characterized by the above-mentioned. The radiation image conversion panel according to item 1. The radiation image conversion panel according to claim 8, wherein the glass transition temperature is 100 ° C or higher.

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