JP2007147431A - Radiation image conversion panel and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation image conversion panel having a high sharpness and contrast as well as a high water resistance, and to provide a method for manufacturing the same. <P>SOLUTION: The radiation image conversion panel comprises a stimulable phosphor layer containing a columnar crystalline stimulable phosphor and a protective layer containing an acrylic resin, both of which layers are formed on a substrate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radiation image conversion panel and a manufacturing method thereof.

  Conventionally, so-called radiography using a silver salt has been used to obtain a radiographic image, but a method for imaging a radiographic image without using a silver salt has been developed. That is, the radiation transmitted through the subject is absorbed by the phosphor, and then the phosphor is excited with a certain energy to emit the radiation energy accumulated in the phosphor as fluorescence, and this fluorescence is detected. A method for imaging is disclosed.

  Specifically, in US Pat. No. 3,859,527, a radiation image using a panel having a photostimulable phosphor layer on a support and using one or both of visible light and infrared light as excitation energy. A conversion method is known.

  The superiority or inferiority of the radiation image conversion method using the radiation image conversion panel depends greatly on the stimulable emission luminance (also referred to as sensitivity) of the radiation image conversion panel and the sharpness of the obtained image. Is greatly influenced by the characteristics of the stimulable phosphor used.

  As one of attempts to obtain a high-sharp radiation image conversion panel, for example, Patent Document 3 discloses an elongated columnar crystal having a certain inclination with respect to the direction of the direction of the support on the support by vapor deposition. A radiation image conversion panel having a phosphor layer formed is described.

  All of the methods for controlling the shape of these phosphor layers suppress the diffusion of stimulated excitation light or stimulated emission in the lateral direction by making the phosphor layer columnar (while repeating reflection at the columnar crystal interface). The phosphor layer formed by vapor deposition includes a component that does not contribute to light emission, such as a binder, in the conventional coating method. The sharpness can be remarkably increased.

  However, the surface of the phosphor layer on which the columnar crystals are formed by the vapor deposition method has irregularities that occur as the crystal grows, and incident stimulable excitation light is reflected and scattered to enter the stimulable phosphor. The effect is reduced, and the incident light spreads in the photostimulable phosphor and sharpness is lowered.

  For this reason, Patent Document 4 discloses a method of polishing a phosphor layer surface using a particulate abrasive material, and Patent Document 5 discloses a method in which unevenness on the surface of the phosphor layer is mechanically scraped using a sponge or felt to make it uniform. A method of polishing to a film thickness is disclosed.

  However, these methods produce irregularities with a relatively long period during polishing, and relatively large abrasive particles are mixed in the phosphor layer, degrading the optical quality of the phosphor layer, and also damaging the columnar crystals. There is a risk of image quality degradation, such as missing images.

  In addition, it is desirable that the radiation image conversion panel is provided with performance that can withstand long-term use without degrading the image quality of the obtained radiation image. However, photostimulable phosphors used in the production of radiation image conversion panels, particularly stimulable phosphors formed by vapor deposition, have a high hygroscopic property, and if left in a room with normal climatic conditions, It absorbs moisture and degrades over time.

  Specifically, for example, when the photostimulable phosphor is placed under high humidity, the radiation sensitivity of the photostimulable phosphor decreases as the absorbed moisture increases. In general, the latent image of the radiographic image recorded on the photostimulable phosphor is regressed with the lapse of time after the irradiation, so that the intensity of the reconstructed radiographic image signal is increased from the irradiation to the excitation light. However, when the photostimulable phosphor absorbs moisture, the latent image retraction speed is accelerated. For this reason, when a radiation image conversion panel having a photostimulable phosphor that has absorbed moisture is used, the reproducibility of the reproduced signal is reduced when the radiation image is read.

  On the other hand, it is known to provide a protective layer in order to improve the moisture resistance of the radiation image conversion panel (see, for example, Patent Document 1 and Patent Document 2).

  Generally, a laser beam having high beam convergence is used as a light source for excitation light of the radiation image conversion panel, but it is scanned with a laser beam through a protective layer made of a polymer film such as a polyethylene terephthalate film (PET film). In this case, scattering of the excitation laser light inside the protective layer film, the peripheral portion of the radiation image conversion panel, or a support plate provided to support the radiation image conversion panel, further transport the radiation image conversion panel, In some cases, the radiation image reading apparatus provided for reading may cause irregular reflection of excitation laser light. When the irregularly reflected excitation light is irradiated and read sequentially while scanning the excitation light on the surface of the radiation image conversion panel, the stimuli of the place away from the place where the excitation light is emitted and the stimulated emission is emitted. In order to excite the phosphor surface and emit stimulated luminescence, there is a problem that sharpness and contrast of the resulting image occur, and the stimulability of the columnar crystal containing the stimulable phosphor In some cases, the phosphor layer could not be fully exhibited.

  In particular, stretched films such as polyethylene terephthalate film and polyethylene naphthalate film have a large refractive index despite having excellent physical properties as a protective layer in terms of transparency, barrier properties, and strength. In addition, a part of the excitation light incident on the inside of the protective film is repeatedly reflected at the upper and lower interfaces of the film and propagates to a place away from the scanned place, emitting stimulated luminescence and reducing sharpness and contrast. . Further, the excitation light propagated inside the protective layer and at the interface of the protective layer is reflected and scattered by the peripheral edge portion of the radiation image conversion panel to emit stimulated light emission, and sharpness and contrast are lowered. Further, the excitation light reflected in the opposite direction to the phosphor surface at the upper and lower interfaces of the protective layer is also a stimulable phosphor surface farther away from the place where it was re-reflected between the photodetection devices and peripheral members and scanned. Is excited to emit stimulated luminescence, which further reduces sharpness and contrast. Since the excitation light is coherent light with a long wavelength from red to infrared, the amount absorbed in the space inside the protective film and inside the reader is small unless it actively absorbs scattered light and reflected light. Propagates to the location and deteriorates sharpness and contrast.

  In addition, a part of the photostimulable luminescence from the photostimulable phosphor irradiated with the excitation light is absorbed or reflected inside the protective film, so that sharpness and contrast are lowered, and the crystallinity of the columnar crystal is reduced. In some cases, the stimulable phosphor layer containing the phosphor cannot be sufficiently exhibited.

In order to prevent the sharpness or contrast from deteriorating, it is conceivable to thin the protective film and shorten the propagation distance of the excitation light inside the protective film. Deterioration of moisture resistance and scratch resistance due to the problem becomes a problem.
JP-A-8-43598 JP 2002-98799 A JP 2002-72381 A German Patent Application Publication No. 2,832,141 JP-T-2004-537646

  An object of the present invention is to provide a radiation image conversion panel having high sharpness and contrast while improving water resistance, and a method for producing the same.

  The above object of the present invention has been achieved by the following constitution.

  1. A radiation image conversion panel comprising a stimulable phosphor layer containing a columnar crystal stimulable phosphor and a protective layer containing an acrylic resin on a support.

  2. 2. The radiation image conversion panel according to 1, wherein the protective layer is ultraviolet curable or thermosetting.

  3. The radiation image conversion panel according to 1 or 2, wherein the protective layer contains polyurea.

  4). 4. The radiation image conversion panel according to any one of 1 to 3, wherein the protective layer has a surface roughness of 0.1 to 1 [mu] m.

  5. The radiation image according to any one of 1 to 4, wherein the photostimulable phosphor is a photostimulable phosphor based on an alkali halide represented by the following general formula (1). Conversion panel.

The general formula ^{(1) M 1 X · aM} 2 X '· bM 3 X ": eA
(In the formula, 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.)
6). 6. The stimulable phosphor having the alkali halide represented by the general formula (1) as a base is a stimulable phosphor represented by the following general formula (2). Radiation image conversion panel.

General formula (2) CsX: A
(In the formula, X represents Br or I, and A represents Eu, In, Ga, or Ce.)
7). In the method for producing a radiation image conversion panel, a step of forming a stimulable phosphor layer containing a columnar crystal of a stimulable phosphor represented by the following general formula (1) on a support; A step of forming a protective layer containing an ultraviolet curable acrylic resin on the photosensitive phosphor layer, and irradiation with ultraviolet light using a filter that absorbs light of the ultraviolet absorption maximum wavelength of the stimulable phosphor, And a step of curing the protective layer. A method for producing a radiation image conversion panel.

The general formula ^{(1) M 1 X · aM} 2 X '· bM 3 X ": eA
(In the formula, 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.)

  According to the present invention, by providing a protective layer containing an acrylic resin, in a radiation image conversion panel having a stimulable phosphor layer containing a columnar crystal stimulable phosphor and having improved brightness and moisture resistance. It can have high sharpness and contrast while improving water resistance.

  As a result of intensive studies, the inventor has obtained, on the support, a radiation image conversion panel having a photostimulable phosphor layer containing a columnar crystal stimulable phosphor and a protective layer containing an acrylic resin, so that brightness and It has been found that a radiation image conversion panel having improved moisture resistance can be obtained.

  Hereinafter, the present invention will be described in detail.

[Support]
As the support used in the radiation image conversion panel of the present invention, various kinds of glass, polymer materials, carbon fiber reinforced resin (CFRP), metals, and the like are used. For example, flat glass such as quartz, borosilicate glass, chemically tempered glass, cellulose acetate film, polyester film, polyethylene terephthalate film, polyamide film, polyimide film, triacetate film, polycarbonate film and other plastic film, foamed polyimide or foamed polyacrylic resin And a metal sheet having a coating layer of the metal oxide, such as a composite resin film, an aluminum sheet, an iron sheet, a copper sheet, etc., coated on both sides with a carbon fiber reinforced resin. Of these, a metal substrate or glass mainly composed of aluminum is preferable. The surface of these supports may be a smooth surface, or may be a mat surface for the purpose of improving the adhesion to the stimulable phosphor layer.

  Moreover, in order to improve the adhesiveness of a support body and a photostimulable phosphor layer, you may provide an adhesive layer in advance on the surface of a support body as needed. The thickness of these supports varies depending on the material of the support to be used, but is generally 80 to 4000 μm, and more preferably 80 to 1000 μm from the viewpoint of handling.

  Further, the spectral absorption characteristic of the support is such that the absorbance on the longer wavelength side (600 to 700 nm) is 1.1 to 10.0 times that on the shorter wavelength side than on the shorter wavelength side (370 to 500 nm). Preferably it is 1.5 to 5.0 times. Setting the spectral absorption characteristics of the support as described above can be achieved by adding a dye during the preparation of the support.

  Examples of the dye that can be used in preparing the support include, for example, perylene pigments described in JP-A-47-30330 and JP-A-56-5552, quinacridone pigments described in JP-A-47-30331, and the like. Bisbenzimidazole pigments described in JP-A-47-18543, aromatic polycondensed ring compounds described in JP-A-47-18544, JP-A-55-98754, JP-A-55-126254, JP-A-55-163543, Azo pigments described in JP-A-44-16373, JP-A-48-30513, JP-A-56-32465, etc., JP-B-50-7434, JP-A-47-37548, JP-A-55-11715, JP-A-56. No. 1944, No. 56-9752, No. 56-2352, No. 56-8050, etc., JP-A 44-1267 40-2780, 52-1667, 46-30035, 49-17535, JP-A-49-11136, 49-99142, 51-109841, 57-148745 Phthalocyanine pigments and the like described in Japanese Patent Publication No. Gazette and the like, and these can be used alone or in combination of two or more. Among these compounds, phthalocyanine compounds are preferable from the viewpoint of the wavelength range. In the present invention, examples of the pigment include zinc oxide, titanium oxide, and zirconium oxide.

[Protective layer]
The present invention relates to a protective layer containing an acrylic resin on a stimulable phosphor layer (hereinafter also simply referred to as a phosphor layer) containing a columnar crystal stimulable phosphor (hereinafter also simply referred to as a phosphor). It is characterized by having.

  As described above, the photostimulable phosphor formed by the vapor deposition method has a high hygroscopic property, and when it is left in a room under normal climatic conditions, it absorbs moisture in the air and deteriorates its performance. The protective layer containing an acrylic resin deposited so as to cover the highly hygroscopic columnar crystal phosphor formed by the deposition method does not directly contact moisture containing air and the phosphor, thereby improving the moisture resistance.

  Further, by adding an ultraviolet curable resin or a thermosetting resin, which will be described later, to make the protective layer ultraviolet curable or thermosetting, the hygroscopicity of the protective layer is lowered and the moisture resistance is further improved. When polyurea described later is contained in the protective layer, moisture resistance is improved for the same reason.

  Although it is not clear why the brightness is improved by providing a protective layer containing an acrylic resin, the protective layer containing an acrylic resin deposited so as to cover the columnar crystal phosphor formed by the deposition method is In order to prevent unevenness of the surface of the phosphor layer on which the columnar crystals are formed by vapor deposition, and to prevent the incident stimulating excitation light from being reflected and scattered to reduce the incident effect on the stimulable phosphor It is estimated.

(Acrylic resin)
Acrylic resin is an acrylic ester or methacrylic ester polymer and is a highly transparent amorphous synthetic resin. Other than polymethyl methacrylate and polyethyl acrylate, acrylamide, acrylonitrile, styrene, etc. Copolymers with these monomers are also included. In addition, since acrylic ester or methacrylic ester is radically polymerized to become an acrylic resin, a monomer is used as the acrylic resin source, a protective layer is formed, and then polymerized to be an acrylic resin.

  Examples of acrylic resin monomers include styrene monomers such as styrene, methyl styrene, methoxy styrene, ethyl styrene, propyl styrene, butyl styrene, phenyl styrene, chloro styrene, methyl acrylate, ethyl acrylate, and acrylic acid. Propyl, butyl acrylate, pentyl acrylate, dodecyl acrylate, stearyl acrylate, ethyl hexyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, dodecyl methacrylate, Examples thereof include acrylic acid esters or methacrylic acid ester monomers such as stearyl methacrylate, ethylhexyl methacrylate, and lauryl methacrylate. Of these, styrene and butyl (meth) acrylate are particularly preferably used.

  In the synthesis of the acrylic resin, a third vinyl compound can be copolymerized. Examples of the third vinyl compound include acid monomers such as acrylic acid, methacrylic acid, maleic anhydride, vinyl acetate, acrylamide, methacrylamide, acrylonitrile, ethylene, propylene, butylene, vinyl chloride, N-vinylpyrrolidone, butadiene, and the like. .

  The acrylic resin may further contain a polyfunctional vinyl compound as a copolymerization component. Examples of the polyfunctional vinyl compound include diacrylates such as ethylene glycol, propylene glycol, butylene glycol, and hexylene glycol, dimethacrylates such as ethylene glycol, propylene glycol, butylene glycol, and hexylene glycol, divinylbenzene, pentaerythritol, and triacrylate. Examples include diallylates of tertiary alcohols such as methylolpropane, triacrylates, pentaerythritol, dimethacrylates of trihydric alcohols such as trimethylolpropane, and trimethacrylates.

  The maximum peak molecular weight of the acrylic resin used in the present invention is usually 7,000 to 200,000, preferably 2 to 150,000, more preferably 3 to 100,000 as a polystyrene conversion value by gel permeation chromatography (GPC) measurement. It is. There may be two or more molecular weight peaks, but a single peak is preferred. The peak of the molecular weight distribution may have a shoulder, and may tail on the high molecular weight side.

(Thermosetting resin, UV curable resin)
In the present invention, it is preferable that the protective layer is cured by heat or ultraviolet light in order to obtain high water resistance and mechanical strength of the radiation conversion panel.

  In order to cure the protective layer by heat, the protective layer contains a thermosetting resin in addition to the acrylic resin. The thermosetting resin refers to a resin that cures when molded by heating, and specific examples of the thermosetting resin of the present invention include, for example, a phenol resin, a melamine resin, an epoxy resin, and an acrylic resin. Resin, epoxy acrylate resin, unsaturated polyester resin, polyester acrylate resin, urethane acrylate resin, spirane resin, diallyl phthalate resin, urea resin, silicone resin, epoxy resin and the like. Of these, urea resins and acrylic resins are preferred. Examples of inorganic resins include colloidal silica and those obtained by polymerizing silicone monomers after hydrolysis. One or more kinds of components selected from these are mixed and used, but it is effective to add and use appropriate amounts of various curing agents, coupling agents and the like as necessary.

  In order to cure the protective layer with ultraviolet rays, the protective layer contains an ultraviolet curable resin in addition to the acrylic resin. The ultraviolet curable resin refers to a resin that is cured through a crosslinking reaction or the like by ultraviolet irradiation. Examples of the ultraviolet curable resin include an ultraviolet curable acrylic urethane resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and an ultraviolet curable epoxy resin. For example, an ultraviolet curable acrylic urethane resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and the like, which are mainly composed of acrylic, are preferable.

  Specific examples include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, and the like.

  In general, UV-curable acrylic urethane resins include 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as acrylates) in addition to products obtained by reacting polyester polyols with isocyanate monomers or prepolymers. And acrylate-based monomers such as 2-hydroxypropyl acrylate, which are easily formed by reaction with acrylate monomers having hydroxyl groups, such as those described in JP-A-59-151110. Can be used.

  Examples of UV curable polyester acrylate resins include those that are easily formed by reacting polyester polyols with 2-hydroxyethyl acrylate and 2-hydroxy acrylate monomers, as disclosed in JP-A-59-151112. Those described can be used.

  Specific examples of the ultraviolet curable epoxy acrylate resin include an epoxy acrylate as an oligomer, a reactive diluent and a photoreaction initiator added to the oligomer, and a reaction. Those described in US Pat. No. 105738 can be used.

  Specific examples of these photoinitiators include benzoin and derivatives, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof. You may use with a photosensitizer.

  The photoinitiator can also be used as a photosensitizer. In addition, when using an epoxy acrylate photoreactive agent, a sensitizer such as n-butylamine, triethylamine, tri-n-butylphosphine can be used.

  Examples of the resin monomer may include general monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, cyclohexyl acrylate, vinyl acetate, and styrene as monomers having one unsaturated double bond. In addition, monomers having two or more unsaturated double bonds include ethylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, 1,4-cyclohexane diacrylate, 1,4-cyclohexyldimethyl adiacrylate, and the above trimethylolpropane. Examples thereof include triacrylate and pentaerythritol tetraacryl ester.

  Examples of commercially available UV curable resins that can be used in the present invention include ADEKA OPTMER KR / BY series: KR-400, KR-410, KR-550, KR-566, KR-567, BY-320B (Asahi Denka ( Co., Ltd.); Koeihard A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T-102, D-102, NS -101, FT-102Q8, MAG-1-P20, AG-106, M-101-C (manufactured by Guangei Chemical Co., Ltd.); Seika Beam PHC2210 (S), PHC X-9 (K-3), PHC2213, DP -10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, SCR900 (manufactured by Dainichi Seika Kogyo Co., Ltd.) KRM7033, KRM7039, KRM7130, KRM7131, ultraviolet ECRYL29201, ultraviolet ECRYL29202 (manufactured by Daicel UCB); RC-5015, RC-5016, RC-5020, RC-5031, RC-5100, RC-5102, RC -5120, RC-5122, RC-5152, RC-5171, RC-5180, RC-5181 (Dainippon Ink Chemical Co., Ltd.); 340 clear (manufactured by China Paint Co., Ltd.); Sun Rad H-601 (manufactured by Sanyo Chemical Industries); SP-1509, SP-1507 (manufactured by Showa Polymer Co., Ltd.); RCC-15C (Grace Japan ( Alonix M-6100, M-8030, M-8060 (manufactured by Toagosei Co., Ltd.); TB3080, TB3042, TB3078B (manufactured by ThreeBond); NOA61 (manufactured by SAN EI TECH), etc. Available.

As a light source for curing the ultraviolet curable resin by a photocuring reaction, any light source that generates ultraviolet light can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. The irradiation conditions vary depending on individual lamps, but the amount of light irradiated may be any degree 20~10000mJ / cm ^2, preferably from 50~2000mJ / cm ^2. The near-ultraviolet region to the visible light region can be efficiently formed by using a sensitizer having an absorption maximum in that region.

(Polyurea)
The polyurea used in the present invention will be described.

  Polyurea is a polymer compound having a urea bond in the repeating unit of the main chain. Polyurea is synthesized from diisocyanate, carbonate, urea, carbonyl sulfide, diurethane or α, ω-diurea and diamine. A typical synthesis method is a method of synthesizing from a diamine represented by the following general formulas (3) and (4) and a diisocyanate represented by the following general formula (5).

General formula (3)
H ₂ NR ¹ NH ₂
(Wherein R ¹ represents a binary linking group.)

(In the formula, R ² represents a binary linking group, and Z is an atomic group necessary for forming a 5- to 6-membered nitrogen-containing heterocyclic ring.)
General formula (5)
O = C = NR ³ N = C = O
(In the formula, R ³ represents a binary linking group.)
Examples of R ¹ , R ² and R ³ include a polymethylene group having 2 to 15 carbon atoms and a phenylene group. The compounds represented by the general formulas (3) to (5) are commercially available and can be easily obtained. Polyurea obtained from R ¹ , R ² and R ³ having 3 or less carbon atoms has poor thermal stability, and preferably 4 or more carbon atoms.

  Examples of polyurea preferably used in the present invention are listed below.

  Polyurea can be used as a deposition source, but two deposition sources of diisocyanate, carbonate, urea, carbonyl sulfide, diurethane or α, ω-diurea, etc., which are polymerized to polyurea after deposition and diamine, should be used. You can also. In the present invention, the latter (vapor deposition polymerization method) is preferable. In the vapor deposition polymerization method, it is preferable that after the vapor deposition, the polymerization reaction is completed by heat treatment, plasma treatment, electron beam irradiation or ultraviolet irradiation, and is strongly fixed to the phosphor. Among diisocyanates, carbonates, ureas, carbonyl sulfides, diurethanes, α, ω-diureas and the like, diisocyanates are preferred because polymerization with diamines reacts quickly even at relatively low temperatures to obtain polyureas having a high degree of polymerization. .

(Dye)
In the present invention, the support is a reflective support, and the protective layer hardly absorbs the stimulating light-emitting component (the light-emitting wavelength region of the stimulable phosphor is 300 to 500 nm), and an extra excitation light component (500 It is preferable to include a coloring matter that absorbs ˜900 nm, particularly 600 to 800 nm, and color it. The characteristics such as sensitivity, sharpness, and granularity change depending on the amount of the dye added at this time, and the mass ratio of the dye and the polyurea in the protective layer is 0.01: 99.99-0, although it depends on the film thickness. 1: 99.9, and more preferably 0.03: 99.97 to 0.09: 99.91.

  The dye used in the radiation image conversion panel of the present invention preferably has an absorption characteristic such that the average absorption rate in the excitation light wavelength region of the phosphor is larger than the average absorption rate in the stimulated emission wavelength region.

  Therefore, what kind of dye is used depends on the type of phosphor used in the radiation image conversion panel. As will be described below, it is practically desirable to use a phosphor that exhibits 300 to 500 nm stimulated emission by excitation light of 500 to 900 nm, but for such a phosphor, in the excitation light wavelength region. Either organic or inorganic dyes can be used so that the average reflectance becomes smaller than the average reflectance in the stimulated emission wavelength region and the difference between the two becomes as large as possible.

Examples of blue to green organic dyes include Zavon First Blue 3G (Hoechst), Estrol Brill Blue N-3RL (Sumitomo Chemical Co., Ltd.), Sumiacryl Blue F-GSL (Sumitomo Chemical Co., Ltd.) Made by D & C Blue No. 1 (made by National Aniline), Spirit Blue (made by Hodogaya Chemical Co., Ltd.), Oil Blue No. 1 603 (manufactured by Orient Co., Ltd.), Kitten Blue A (manufactured by Ciba-Geigy), Eisen Cachilon Blue GLH (manufactured by Hodogaya Chemical Co., Ltd.), Lake Blue A, F, H (manufactured by Kyowa Sangyo Co., Ltd.) Rhodaline Blue 6GX (manufactured by Kyowa Sangyo Co., Ltd.), Brimocyanin 6GX (manufactured by Inabata Sangyo Co., Ltd.), Brill Acid Green 6BH (manufactured by Hodogaya Chemical Co., Ltd.), Cyanine Blue BNRS (manufactured by Toyo Ink Co., Ltd.) And Lionol Blue SL (manufactured by Toyo Ink Co., Ltd.). Examples of blue to green inorganic dyes include ultramarine blue, cobalt blue, cerulean blue, chromium oxide, and TiO ₂ —ZnO—CoO—NiO pigments, but the present invention is not limited thereto. As the blue to green organic pigment, phthalocyanine is preferable. Of the phthalocyanines, metal phthalocyanine-based organometallic complex dyes, and copper phthalocyanine-based organometallic complex dyes are most preferable.

(Protective layer forming method)
The protective layer containing an acrylic resin or the like can be provided by a coating method or a vapor deposition method, but is preferably provided by a vapor deposition method.

  The protective layer deposited so as to cover the columnar crystal phosphor formed by the deposition method improves the moisture resistance and scratch resistance of the phosphor layer, and the phosphor layer is cracked or peeled off. As described above, the image diagnosis system using the radiation image conversion panel can obtain an image having water resistance and brightness.

  In the vapor deposition method, the deposition order of the protective layer components can be changed. For example, by depositing the dye prior to the acrylic resin, the acrylic resin having a larger amount than the dye can be transferred to the tip side of the columnar crystal (from the support). By covering the far side), it is possible to prevent the amount of dye deposited on the back side of the columnar crystal (the side close to the support) from decreasing and the effect of preventing the diffusion of excitation light from decreasing.

  The thickness of the protective layer is preferably from 0.01 to 10 μm, more preferably from 0.05 to 5 μm, still more preferably from 0.1 to 2 μm. The heating temperature for vapor deposition is preferably 100 to 300 ° C. The degree of vacuum at the time of vapor deposition is equivalent to the vapor deposition method for forming the phosphor layer described later.

  In a method for producing a radiation image conversion panel having a stimulable phosphor layer containing a columnar crystal stimulable phosphor and a protective layer containing an acrylic resin on a support, the protective layer is UV curable. In addition, it is preferable that the protective layer is cured by irradiating with ultraviolet light using a filter that absorbs light of the ultraviolet absorption maximum wavelength of the stimulable phosphor. By this manufacturing method, deterioration of the photostimulable phosphor due to ultraviolet light irradiation can be suppressed.

(Surface roughness)
The surface roughness of the protective layer is preferably 0.1 to 1 μm. In the present invention, the surface roughness means a surface roughness Ra (average surface roughness) defined by JIS-B-0601. As a measuring apparatus, for example, it can be measured by a known surface roughness measuring method such as a stylus method or laser interferometry.

  In order to obtain this surface roughness, it is preferable to add fine particles to the protective layer. Examples of such fine particles include resin fine particles such as melamine and PMMA as organic compounds, and examples of inorganic compounds include titanium oxide, zinc oxide, calcium carbonate, aluminum oxide, kaolin, clay, silica, talc, and mica. Silica is preferable from the viewpoint of dispersibility, and the larger the oil absorption (specific surface area, bulk specific gravity) is particularly preferable. The addition amount is usually 0.1 to 40% by mass, preferably 1 to 30% by mass, based on the total solid content of the protective layer.

[Stimulable phosphor]
Next, the stimulable phosphor represented by the general formula (1) preferably used in the present invention will be described.

In the general formula (1), M ¹ represents at least one alkali metal atom selected from each atom such as Li, Na, K, Rb and Cs, and more particularly at least one selected from each atom of Rb and Cs. Are preferably alkaline earth metal atoms, more preferably Cs atoms.

M ² represents at least one divalent metal atom selected from atoms such as Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu and Ni, and among them, Be, Mg, Ca are preferably used. , A divalent metal atom selected from each atom such as Sr and Ba.

M ³ is at least one selected from each atom of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In. A trivalent metal atom of a kind is represented, and among them, a trivalent metal atom selected from Y, Ce, Sm, Eu, Al, La, Gd, Lu, Ga, and In atoms is preferably used.

  A is at least one selected from the atoms of Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu, and Mg. Metal atom.

  X, X ′, and X ″ each represents an atom represented by at least one halogen selected from F, Cl, Br, and I atoms. From the viewpoint of improving the stimulated emission luminance of the phosphor, F, Cl, and Br At least one selected from the halogen atoms is preferable, and at least one halogen atom selected from Br and I atoms is more preferable.

  The photostimulable phosphor represented by the general formula (1) based on the alkali halide is preferably a stimulable phosphor represented by the following general formula (2).

General formula (2)
CsX: A
(In the formula, X represents Br or I and is preferably Br. A represents Eu, In, Ga or Ce, and Eu is preferable.)
The photostimulable phosphor represented by the general formula (1) is produced, for example, by the production 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 a 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 (1), 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 (1), a is 0 ≦ a <0.5, preferably 0 ≦ a <0.01, b is 0 ≦ b <0.5, preferably 0 ≦ b ≦ 10 ^{−. 2} 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 as to adjust the pH value of the obtained aqueous solution to 0 to 7, and then water is evaporated and vaporized.

  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 aforementioned 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.

[Formation of phosphor layer]
Further, the photostimulable phosphor layer of the present invention is formed by a vapor phase growth method.

  As the vapor phase growth method of the photostimulable phosphor, there are a vapor deposition method, a sputtering method, a CVD method, an ion plating method, and others. In the present invention, the vapor deposition method is used.

In the vapor deposition method, first, a support is placed in a vapor deposition apparatus, and then the inside of the apparatus is evacuated to a degree of vacuum of about 1.33 × 10 ⁻⁴ Pa.

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

  As a result, a 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 process, 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. .

  After the vapor deposition, the radiation image conversion panel of the present invention is manufactured by providing the protective layer on the side opposite to the support side of the phosphor layer as necessary.

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

Moreover, you may heat-process a fluorescent substance layer after completion | finish of 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.

  The growth rate of the photostimulable phosphor layer in vapor phase growth is preferably 0.05 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. In addition, when 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 vapor deposition method, since the binder is not present, the packing density of the stimulable phosphor can be increased, and a radiation image conversion panel preferable in terms of sensitivity and resolution can be obtained.

  The film thickness of the phosphor layer varies depending on the intended use of the radiation image conversion panel and the type of phosphor, but is 50 μm to 1 mm, preferably 50 to 300 μm, more preferably from the viewpoint of obtaining the effects of the present invention. Is 100 to 300 μm, particularly preferably 150 to 300 μm.

  In producing the phosphor layer by the vapor phase growth method described above, the temperature of the support on which the phosphor layer is formed is preferably set to 100 ° C. or higher, more preferably 150 ° C. or higher, and particularly preferably 150 to 400 ° C.

  From the viewpoint of obtaining a radiation image conversion panel exhibiting high sharpness, the reflectance of the phosphor layer of the present invention is preferably 20% or more, more preferably 30% or more, and further preferably 40% or more. It is. The upper limit is 100%.

[Fillers such as binders]
In addition, the gap between the columnar crystals may be filled with a filler such as a binder, and in addition to reinforcing the phosphor layer, it may be filled with a highly light-absorbing substance, a highly light-reflecting substance, etc. In addition to providing a reinforcing effect, it is effective for reducing the light diffusion in the lateral direction of the stimulated excitation light incident on the phosphor layer.

  A highly reflective substance refers to a substance having a high reflectance with respect to stimulating excitation light. For example, a white pigment and a green to red color material such as aluminum, magnesium, silver, indium, and other metals are used. be able to. 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). , Sr, and Ca, 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.

  Since these white pigments have a strong hiding power and a high refractive index, they can easily scatter photostimulated luminescence by reflecting or refracting light, thereby significantly improving the sensitivity of the resulting radiation image conversion panel. it can.

  Moreover, as a substance 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. Materials are also mentioned.

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

  FIG. 1 is a schematic view showing an example of an imaging system using the radiation image conversion panel of the present invention.

  In FIG. 1, 21 is a radiation generator, 22 is a subject, 23 is a radiation image conversion panel having a stimulable phosphor layer containing a stimulable phosphor, and 24 is a radiation latent image of the radiation image conversion panel 23. A stimulated excitation light source for emitting as luminescence, 25 is a photoelectric conversion device for detecting the stimulated luminescence emitted from the radiation image conversion panel 23, and 26 reproduces the photoelectric conversion signal detected by the photoelectric conversion device 25 as an image. 27 is an image display device that displays the reproduced image, and 28 is a filter that cuts off the reflected light from the stimulating excitation light source 24 and transmits only the light emitted from the radiation image conversion panel 23. is there.

  FIG. 1 shows an example of obtaining a radiation transmission image of a subject. However, when the subject 22 itself emits radiation, the radiation generator 21 is not particularly necessary.

  The photoelectric conversion device 25 and the subsequent devices are not limited to the above as long as the optical information from the radiation image conversion panel 23 can be reproduced as an image in some form.

  As shown in FIG. 1, when the subject 22 is placed between the radiation generator 21 and the radiation image conversion panel 23 and irradiated with the radiation R, the radiation R is transmitted according to the change of the radiation transmittance of each part of the subject 22, The transmission image RI (that is, an image of the intensity of radiation) enters the radiation image conversion panel 23.

  The incident transmitted image RI is absorbed by the photostimulable phosphor layer of the radiation image conversion panel 23, so that a number of electrons and / or holes proportional to the amount of radiation absorbed in the photostimulable phosphor layer are generated. Occurs and accumulates at the trap level of the photostimulable phosphor.

  That is, a latent image in which the energy of the radiation transmission image is accumulated is formed. Next, this latent image is made visible by being excited with light energy.

  Further, the photostimulable phosphor layer is irradiated with the photostimulable excitation light source 24 to expel electrons and / or holes accumulated at the trap level, and the accumulated energy is emitted as photostimulated luminescence.

  The intensity of the emitted stimulated emission is proportional to the number of accumulated electrons and / or holes, that is, the intensity of the radiation energy absorbed in the stimulable phosphor layer of the radiation image conversion panel 23. The optical signal is converted into an electrical signal by a photoelectric conversion device 25 such as a photomultiplier tube, and is reproduced as an image by an image reproduction device 26, and this image is displayed by an image display device 27.

  The image reproduction device 26 is more effective not only for reproducing an electrical signal as an image signal but also using an apparatus that can perform so-called image processing, image calculation, image storage, storage, and the like.

  In addition, when excited by light energy, it is necessary to separate the reflected light of the stimulated excitation light from the stimulated emission emitted from the stimulable phosphor layer, and it is emitted from the stimulable phosphor layer. Photoelectric converters that receive light emission generally have high sensitivity to light energy with a short wavelength of 600 nm or less, so that the stimulated emission emitted from the stimulable phosphor layer has a spectral distribution in the short wavelength region as much as possible. What you have is desirable.

  The emission wavelength range of the photostimulable phosphor of the present invention is 300 to 500 nm, while the photostimulable excitation wavelength range is 500 to 900 nm, which satisfies the above-mentioned conditions at the same time. Recently, downsizing of diagnostic devices has progressed. A semiconductor laser that has a high output and is easy to be compacted is preferably used for reading an image of the radiation image conversion panel, and the wavelength of the laser light is preferably 680 nm. The stimulable phosphor incorporated in the panel exhibits very good sharpness when using an excitation wavelength of 680 nm.

  That is, all of the photostimulable phosphors of the present invention emit light having a main peak at 500 nm or less, the photostimulated excitation light can be easily separated, and coincides well with the spectral sensitivity of the photoreceiver. The sensitivity of the image receiving system can be increased.

  As the stimulated excitation light source 24, a light source including the stimulated excitation wavelength of the stimulable phosphor used in the radiation image conversion panel 23 is used. In particular, when laser light is used, the optical system becomes simple and the excitation light intensity can be increased, so that the photostimulative emission efficiency can be increased, and a more preferable result can be obtained.

Examples of lasers include He-Ne laser, He-Cd laser, Ar ion laser, Kr ion laser, N ₂ laser, YAG laser and its second harmonic, ruby laser, semiconductor laser, various dye lasers, copper vapor There are metal vapor lasers such as lasers. Normally, a continuous wave laser such as a He—Ne laser or an Ar ion laser is desirable, but a pulsed laser can also be used if the scanning time and pulse of one pixel of the panel are synchronized.

  Further, when using a method of separating light emission using a delay of light emission as shown in JP-A-59-22046 without using a filter 28, a pulsed laser is used rather than a continuous wave laser. It is preferable to use it.

  Among the various laser light sources described above, the semiconductor laser is particularly preferably used because it is small and inexpensive and does not require a modulator.

  Since the filter 28 transmits the stimulated emission emitted from the radiation image conversion panel 23 and cuts the stimulated excitation light, this is the excitation of the stimulable phosphor contained in the radiation image conversion panel 23. It is determined by the combination of the emission wavelength and the wavelength of the stimulated excitation light source 24.

  For example, in the case of a practically preferable combination in which the photostimulation excitation wavelength is 500 to 900 nm and the photostimulation emission wavelength is 300 to 500 nm, examples of the filter include C-39, C-40, and V-40 manufactured by Toshiba Corporation. Purple-blue glass filters such as V-42, V-44, Corning 7-54, 7-59, Spectrofilm BG-1, BG-3, BG-25, BG-37, BG-38, etc. Can be used. When an interference filter is used, a filter having an arbitrary characteristic can be selected and used to some extent. The photoelectric conversion device 25 may be any device capable of converting a change in light quantity into a change in electronic signal, such as a photoelectric tube, a photomultiplier tube, a photodiode, a phototransistor, a solar cell, or a photoconductive element.

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

Example (Production of Radiation Image Conversion Panel 1)
<Formation of phosphor layer>
On the surface of a 1 mm-thick crystallized glass (manufactured by Nippon Electric Glass Co., Ltd.) support, a stimulable phosphor (which is set to θ1 = 5 degrees and θ2 = 5 degrees) using the vapor deposition apparatus shown in FIG. A photostimulable phosphor layer having CsBr: Eu) was formed.

  In the vapor deposition apparatus shown in FIG. 2, an aluminum slit is used, the distance d between the support and the slit is set to 60 cm, vapor deposition is performed while the support is transported in a direction parallel to the support, and photostimulable fluorescence is performed. The thickness of the body layer was adjusted to 300 μm.

  In vapor deposition, the support was placed in a vapor deposition device, and then, the phosphor raw material (CsBr: Eu) was press-molded using a vapor deposition source and placed in a water-cooled crucible.

Thereafter, the inside of the vapor deposition device was once evacuated, N ₂ gas was introduced again, the degree of vacuum was adjusted to 0.133 Pa, and then vapor deposition was performed while maintaining the temperature of the support at about 150 ° C. Deposition was terminated when the thickness of the photostimulable phosphor layer reached 300 μm, and this phosphor layer was then heat-treated at 100 ° C.

  On the obtained crystallized glass support, a phosphor layer (porosity: 2%) having a structure in which columnar crystal phosphors having a width of about 2.5 μm and a length of about 150 μm are densely forested in the vertical direction is formed. It had been. 3A shows a cross-sectional view of the phosphor layer, and FIG. 3B shows a surface view of the phosphor layer.

<Formation of protective layer>
Next, TB3078B (acrylic resin liquid, manufactured by Three Bond Co., Ltd.) was applied on the phosphor layer with a wire bar. The coating layer was cured by irradiating ultraviolet light with a metal halide lamp using a filter that absorbs light having a maximum wavelength of ultraviolet absorption of the stimulable phosphor. The irradiation light amount was 150 mJ / m ² , the film thickness of the protective layer 1 after the curing treatment was about 10 μm, and the surface roughness of the protective layer 1 was 0.1 μm.

Further, after evacuating the inside of the vapor deposition device, N ₂ gas was introduced again and the degree of vacuum was adjusted to 0.001 Pa, and then the polynonamethylene urea was formed on the protective layer 1 while maintaining the temperature of the support at about 150 ° C. Was deposited to form a protective layer 2. The thickness of the protective layer 2 was about 0.2 μm, and the surface roughness of the protective layer 2 was 0.1 μm. The radiation image conversion panel 1 was produced by the above.

  FIG. 4 is a cross-sectional view of the phosphor layer showing that a protective layer made of acrylic resin and polynonamethylene urea is formed at the phosphor tip. The surface of the phosphor layer has irregularities, but the surface of the protective layer is flat without irregularities.

(Preparation of radiation image conversion panel 2)
In preparation of the radiation image conversion panel 1, after forming a fluorescent substance layer, without forming a protective layer, the surface of the fluorescent substance layer is uneven | corrugated by sponge using the method described in the specification of JP-T-2004-537646. The radiation image conversion panel 2 was produced by mechanically removing the unevenness.

(Preparation of radiation image conversion panel 3)
In preparation of the radiation image conversion panel 1, the radiation image conversion panel 3 was produced without forming a protective layer.

(Preparation of radiation image conversion panel 4)
In preparation of the radiation image conversion panel 1, after forming a fluorescent substance layer, the following coating liquid for protective layers was apply | coated so that the coating thickness might be set to 5 micrometers with a doctor coater. This coating layer was irradiated with ultraviolet rays for 10 seconds with a high-pressure mercury lamp with an output of 80 W / cm and completely cured to form a protective layer, whereby a radiation image conversion panel 4 was produced.

<Coating liquid for protective layer>
Bisphenol A glycidyl ether 75% by mass
3,4-epoxycyclohexylmethyl carboxylate 18% by mass
Triallylsulfonium hexafluoroantimony salt 7% by mass
(Evaluation of radiation image conversion panel)
Each radiation image conversion panel produced as described above was evaluated for luminance and water resistance according to the following method. The results are shown in Table 1.

<Luminance>
The measurement of luminance was performed by irradiating the radiation image conversion panel with X-rays having a tube voltage of 80 kVp at 10 mAs at a distance of 2 m between the radiation source and the plate, and then setting the radiation image conversion panel on the Regius 350 for reading. The luminance was determined from the electrical signal from the obtained photomultiplier. The luminance is expressed as a relative value where the luminance of the radiation image conversion panel 3 is 100. In addition, it has been empirically found that a radiation image conversion panel with high brightness is superior in sharpness.

<water resistant>
The radiation image conversion panel is subjected to a forced deterioration treatment (forced deterioration treatment panel) for 5 days in a 40 ° C., 90% RH environment, and then, together with an unprocessed radiation image conversion panel (reference panel), the method described below. Sensitivity measurement was performed.

  Sensitivity is measured by irradiating X-rays with a tube voltage of 80 kVp for each radiation image conversion panel with or without forced deterioration processing, and then scanning the panel with He-Ne laser light (633 nm) to emit light from the phosphor layer. The stimulated emission is received by a photoreceiver (photoelectron image multiplier of spectral sensitivity S-5), its intensity is measured, this is defined as sensitivity, and the sensitivity deterioration rate of the forced deterioration processing panel relative to the reference panel And ranked according to the following criteria.

◎: Sensitivity deterioration rate is less than 5% ○: Sensitivity deterioration rate is less than 5-10% △: Sensitivity deterioration rate is less than 10-20% ×: Sensitivity deterioration rate is 20% or more There is no practical problem.

  The evaluation results are shown in Table 1.

  From Table 1, it can be seen that the radiation image conversion panel having the protective layer having the configuration of the present invention is superior in moisture resistance and sharpness to the comparative product.

It is the schematic which shows an example of the imaging | photography system using the radiographic image conversion panel of this invention. It is the schematic which shows an example of the method of producing a stimulable fluorescent substance layer on a support body by vapor deposition. It is sectional drawing (A) of a photostimulable phosphor layer, and the surface figure (B) of a photostimulable phosphor layer. It is sectional drawing of the fluorescent substance layer which shows that the protective layer which consists of acrylic resin and polynonamethylene urea is formed in the fluorescent substance front-end | tip part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Support body 12 Stimulable fluorescent substance layer 13 Columnar crystal 14 Space | gap formed between columnar crystals 15 Support body holder 21 Radiation generator 22 Subject 23 Radiation image conversion panel 24 Photoexcitation light source 25 Photoelectric conversion device 26 Image reproducing device 27 Image display device 28 Filter

Claims (7)

A radiation image conversion panel comprising a stimulable phosphor layer containing a columnar crystal stimulable phosphor and a protective layer containing an acrylic resin on a support. The radiation image conversion panel according to claim 1, wherein the protective layer is ultraviolet curable or thermosetting. The radiation image conversion panel according to claim 1, wherein the protective layer contains polyurea. The radiation image conversion panel according to claim 1, wherein the protective layer has a surface roughness of 0.1 to 1 μm. 5. The stimulable phosphor according to claim 1, wherein the photostimulable phosphor is a stimulable phosphor based on an alkali halide represented by the following general formula (1). Radiation image conversion panel.
The general formula ^{(1) M 1 X · aM} 2 X '· bM 3 X ": eA
(In the formula, 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.) 6. The photostimulable phosphor represented by the general formula (1) is a photostimulable phosphor represented by the following general formula (2). The radiation image conversion panel described.
General formula (2) CsX: A
(In the formula, X represents Br or I, and A represents Eu, In, Ga, or Ce.) In the method for producing a radiation image conversion panel, a step of forming a stimulable phosphor layer containing a columnar crystal of a stimulable phosphor represented by the following general formula (1) on a support; A step of forming a protective layer containing an ultraviolet curable acrylic resin on the photosensitive phosphor layer, and irradiation with ultraviolet light using a filter that absorbs light of the ultraviolet absorption maximum wavelength of the stimulable phosphor, And a step of curing the protective layer. A method for producing a radiation image conversion panel.
The general formula ^{(1) M 1 X · aM} 2 X '· bM 3 X ": eA
(In the formula, 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.)

Images