JP2006133153A - Radiation image conversion panel using photostimulable phosphor and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation image conversion panel with well-balanced sharpness and coating property while holding high sensitivity that is a radiation image conversion panel using columnar crystals of an alkali halide-based photostimulable phosphor in a phosphor layer. <P>SOLUTION: The radiation image conversion panel comprises at least an undercoat layer, a photostimulable phosphor layer, and a protective layer laminated on a support body in this order, the phosphor layer being composed of columnar crystals of the alkali halide-based photostimulable phosphor. The excitation light reflectance on the photostimulable phosphor layer side of the support body is 80% or more, and an intermediate layer has an excitation light transmittance of 50% or more and 100% or less, and a film thickness of 0.1-10 μm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

  In recent years, a method of imaging a radiation image has been used by a radiation image conversion panel using a stimulable phosphor.

  The stimulable phosphor layer of the radiation image conversion panel used in this radiation image conversion method is required to have high radiation absorption rate and light conversion rate, good image graininess, and high sharpness. .

  In order to improve the sensitivity and image quality by adjusting a plurality of factors related to sensitivity and image quality, various studies have been conducted so far. Among them, as a means for improving the sharpness of a radiographic image, for example, an attempt is made to improve the sensitivity and sharpness by controlling the shape of the photostimulable phosphor formed itself.

  As one of the attempts, for example, Japanese Patent Application Laid-Open No. 61-142497 discloses a photostimulability composed of fine pseudo-columnar blocks formed by depositing a photostimulable phosphor on a support having a fine uneven pattern. There is a method using a phosphor layer.

  Further, as described in JP-A-61-142500, a crack between columnar blocks obtained by depositing a photostimulable phosphor on a support having a fine pattern is further subjected to a shock treatment. A method using a radiation image conversion panel having a developed stimulable phosphor layer, and further a stimulable phosphor formed on the surface of a support as described in JP-A-62-39737 A method of using a radiation image conversion panel in which a layer is cracked from its surface side to form a pseudo-columnar shape, and further, as described in JP-A-62-110200, a brightness having a cavity by vapor deposition on the upper surface of a support. There has also been proposed a method in which a cavity is grown by heat treatment and a crack is formed after forming the stimulable phosphor layer.

  Radiation image conversion having a photostimulable phosphor layer on a support (hereinafter also referred to as a substrate) formed by a vapor deposition method on which elongated columnar crystals having a certain inclination with respect to the normal direction of the support are formed. A panel has been proposed (see, for example, Patent Document 1).

  In attempts to control the shape of these photostimulable phosphor layers, all of the photostimulable phosphor layers are made columnar to suppress the lateral diffusion of photostimulated excitation light (stimulated luminescence) ( Therefore, it is possible to remarkably increase the sharpness of an image due to stimulated light emission.

  In the radiation image conversion panel having the photostimulable phosphor layer formed by vapor phase growth (deposition), the relationship between the sensitivity and the sharpness is improved, but the pseudo-columnar or columnar photostimulable phosphor is also used. Attempts have been made to further improve image quality by suppressing reflection and refraction at the layer interface in the radiation image conversion panel by further combining a low-refractive index layer with a phosphor layer made of crystals (for example, patent documents). 2).

However, since the phosphor layer composed of these columnar photostimulable phosphor crystals is formed with elongated columnar crystals on the substrate, the adhesion (adhesiveness) to the substrate may not be sufficient. It was easy to peel off and it was necessary to improve durability. In particular, when a highly reflective support is used, the tendency of the film-attaching property to deteriorate is remarkable (see, for example, Patent Document 3).
JP-A-2-58000 Japanese Patent Laid-Open No. 1-1131498 JP 2004-251883 A

  The object of the present invention is to maintain the high sensitivity characteristic of a radiation image conversion panel using columnar crystals of alkali halide-based stimulable phosphors in the phosphor layer, and to balance high sharpness and film-forming properties. The present invention provides a radiation image conversion panel and a method for manufacturing the radiation image conversion panel.

As a result of intensive studies by the inventors of the present invention, it has been found that the object of the present invention can be achieved by any of the following configurations.
(Claim 1)
Radiation in which at least an undercoat layer, a stimulable phosphor layer, and a protective layer are laminated in this order on a support, and the phosphor layer is composed of columnar crystals of an alkali halide-based stimulable phosphor In the image conversion panel, the excitation light reflectance of the support on the side of the stimulable phosphor layer is 80% or more, the excitation light transmittance of the intermediate layer is 50% or more and 100% or less, and the film thickness is 0. A radiation image conversion panel characterized by having a thickness of 1 to 10 μm.
(Claim 2)
The film thickness of the undercoat layer is 0.1 to 20% with respect to the film thickness of all the constituent layers provided on the photostimulable phosphor layer side of the support. The radiation image conversion panel described.
(Claim 3)
The radiation image conversion panel according to claim 1, wherein the columnar crystal of the alkali halide stimulable phosphor is composed of a CsBr columnar crystal.
(Claim 4)
In the manufacturing method of the radiographic image conversion panel of any one of Claims 1-3, after applying a subbing layer on a support body and drying, forming a photostimulable phosphor layer by a vapor deposition method. A method for producing a radiation image conversion panel.

  According to the present invention, high sensitivity, which is a feature of the radiation image conversion panel using columnar crystals of alkali halide photostimulable phosphors in the phosphor layer, is maintained, and the balance between sharpness and film-forming properties is achieved. A radiation image conversion panel and a method for manufacturing the radiation image conversion panel can be provided.

  The compound, layer structure, production method and the like constituting the present invention will be further described below.

[Support (base material)]
The support of the present invention is usually used for a radiation image conversion panel, for example, aluminum, quartz glass, plastic resin, etc. are used. However, in terms of achieving the effects of the present invention, a metal substrate mainly composed of aluminum, CFRP and an aramid laminate are preferably used.

  However, in order to achieve high sensitivity, the excitation light reflectance on the photostimulable phosphor layer side of the support needs to be 80% or more, and if it is less than this, the sensitivity as a radiation image conversion panel is lowered. .

[Undercoat layer (intermediate layer)]
In addition, it is preferable to have an undercoat layer (also referred to as an intermediate layer) such that the surface of the support is polymer-coated, since the effects of the present invention are further exhibited. The film thickness of the intermediate layer is 0.1 to 10 μm, and the excitation light transmittance needs to be 50% or more and 100% or less. Moreover, it is desirable that the thickness of the undercoat layer is 0.1 to 20% with respect to the thickness of all the constituent layers provided on the photostimulable phosphor layer side of the support.

  Examples of the binder used in the polymer coating treatment include proteins such as gelatin, derivative gelatin, colloidal albumin, and casein; cellulose compounds such as carboxymethyl cellulose, diacetyl cellulose, and triacetyl cellulose; agar, sodium alginate, starch derivatives, and the like. Synthetic hydrophilic colloids such as polyvinyl alcohol, poly-N-vinylpyrrolidone, polyacrylic acid copolymers, polyacrylamide or derivatives and partial hydrolysates thereof, polyvinyl acetate, polyacrylonitrile, polyacrylic acid esters And other vinyl polymers and copolymers thereof, natural products such as rosin and shellac and derivatives thereof, and many other synthetic resins.

  Also used are emulsions of styrene-butadiene copolymer, polyacrylic acid, polyacrylate ester and derivatives thereof, polyvinyl acetate, vinyl acetate-acrylate copolymer, polyolefin, olefin-vinyl acetate copolymer, etc. be able to. Other organic semiconductors such as carbonates, polyesters, urethanes, epoxy resins, polyvinyl chloride, polyvinylidene chloride and polypyrrole can also be used. Moreover, these binders can also be used in mixture of 2 or more types.

[Stimulable phosphor layer]
The photostimulable phosphor layer of the present invention is composed of a columnar crystal of an alkali halide photostimulable phosphor. The composition means that the stimulable phosphor layer may contain other components, but the columnar crystal of the alkali halide stimulable phosphor is the main component, It means that it accounts for at least 50% by mass or more in the stimulable phosphor layer mass.

  The alkali halide photostimulable phosphor is not particularly limited, but is preferably represented by the following general formula (1).

The general formula ^{(1) M 1 X · aM} 2 X '2 · bM 3 X "3: eA
[Wherein M ¹ is at least one alkali metal atom selected from Li, Na, K, Rb and Cs, and M ² is selected from Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu and Ni. At least one kind of divalent metal atom selected, M ³ is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al , At least one trivalent metal atom selected from Ga and In, and X, X ′ and X ″ are each at least one halogen atom selected from F atom, Cl atom, Br atom and I atom, A is at least one metal selected from Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg An atom, and a, , E is respectively represent a number between 0 ≦ a <0.5,0 ≦ b <0.5,0 <e ≦ 0.2.]
Next, the stimulable phosphor represented by the general formula (1) preferably used in the present invention will be described.

In the photostimulable phosphor represented by the general formula (1), M ^I represents at least one alkali metal atom selected from each atom such as Na, K, Rb and Cs. At least one alkaline earth metal atom selected from each atom is preferred, and a Cs atom is more preferred.

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 are preferably used. , A divalent metal atom selected from atoms such as Ca, Sr and Ba.

M ³ is at least selected from each atom such as Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga and In. One kind of trivalent metal atom is represented, and among these, trivalent metal atoms selected from each atom such as Y, Ce, Sm, Eu, Al, La, Gd, Lu, Ga and In are preferred. is there.

  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. Of these, an Eu metal atom is preferable.

  From the viewpoint of improving the photostimulable emission brightness of the photostimulable phosphor, X, X ′, and X ″ each represent at least one halogen atom selected from F, Cl, Br, and I atoms. At least one halogen atom selected from Br is preferable, and at least one halogen atom selected from Br and I atoms is more preferable.

  Among these, as the stimulable phosphor used in the present invention, a CsBr-based stimulable phosphor such as CsBr: Eu is preferable.

  The photostimulable phosphor represented by the general formula (1) of the present invention is produced, for example, by the production method described below.

As a phosphor material, for example,
(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) At least one compound selected from compounds of AlCl ₃ , GaBr ₃ and InCl ₃ is used.

  (D) As the raw material of the activation part, 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 is used.

In the compound represented by the general formula (I), a is 0 ≦ a <0.5, preferably 0 ≦ a <0.01, and b is 0 ≦ b <0.5, preferably 0 ≦ b ≦. 10 ⁻² and e are 0 <e ≦ 0.2, preferably 0 <e ≦ 0.1.

  In order to obtain the photostimulable phosphor, the phosphor materials (a) to (d) are weighed so as to have a mixed composition in the numerical range, and sufficiently mixed using a mortar, ball mill, mixer mill or the like. To do.

  Once fired, the fired product is taken out of the electric furnace and pulverized. After that, the fired powder is again filled in a heat-resistant container and placed in the electric furnace, and then fired again under the same firing conditions as above. The luminous brightness of the body can be further increased, and when the fired product is cooled to the room temperature from the firing temperature, the desired phosphor can also be obtained by removing the fired product from the electric furnace and allowing it to cool in the air. However, it may be cooled in the same weak reducing atmosphere or neutral atmosphere as in the 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.

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

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

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

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

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

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

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

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

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

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

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

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

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

  The growth rate of the stimulable phosphor layer in the vapor phase growth is preferably 0.05 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 low, which is not preferable. If the growth rate exceeds 300 μm / min, it is difficult to control the growth rate.

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

  The crucible for vapor deposition differs depending on the heating method such as resistance heating method, halogen heating method EB (electron beam) method and the like.

  The film thickness of the photostimulable phosphor layer varies depending on the purpose of use of the radiation image conversion panel and the type of stimulable phosphor, but is preferably 50 μm to 1 mm from the viewpoint of obtaining the effects described in the present invention. Preferably it is 50-800 micrometers.

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

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

Examples of the white pigment include TiO ₂ (anatase type, rutile type), MgO, PbCO ₃ · Pb (OH) ₂ , BaSO ₄ , Al ₂ O ₃ , M (II) FX (where M (II) is Ba). , 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.

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

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

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

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

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

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

  In order to deposit the stimulable phosphor layer, it is preferable to form the stimulable phosphor layer by various deposition methods after applying the undercoat layer on the support and drying it.

  In order to form the photostimulable phosphor layer by a vapor phase growth method, typically, a vapor deposition apparatus as shown in the figure is used.

In FIG. 1, 1 is a vapor deposition apparatus, 2 is a vacuum chamber, 3 is a support rotating mechanism (support rotating function), 4 is a support, 5 is an evaporation source, and 6 is a support surface temperature control heater. . D ₁ is the distance between the support 4 and the evaporation source 5.

[Protective layer]
The photostimulable phosphor layer of the present invention has a protective layer.

  The protective layer may be formed by directly coating a protective layer coating solution on the photostimulable phosphor layer, or a protective layer separately formed in advance may be installed on the photostimulable phosphor layer. Alternatively, a stimulable phosphor layer may be formed on a separately formed protective layer, and a means for setting with the support may be employed.

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

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

  Furthermore, the thickness of these protective layers is preferably 0.1 to 2000 μm.

[How to use the radiation image conversion panel]
The emission wavelength range of the photostimulable phosphor of the present invention is usually 300 to 500 nm, while the stimulated excitation wavelength range is often 500 to 900 nm. Recently, downsizing of diagnostic devices has progressed, and a semiconductor laser that has a high output and is easy to make compact is preferred as an excitation wavelength used for reading an image of a radiation image conversion panel. The wavelength of the laser beam is 680 nm. In many cases, the photostimulable phosphor incorporated in the radiation image conversion panel of the present invention preferably exhibits extremely good sharpness when an excitation wavelength of 680 nm is used.

  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 is easily separated, and coincides well with the spectral sensitivity of the light receiver, so that light can be received efficiently. The sensitivity of the image receiving system can be increased.

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.

  In addition, when using a method of separating light emission delay as disclosed in JP-A-59-22046, it is preferable to use a pulsed laser rather than a continuous wave laser.

  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.

  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. If an interference filter is used, a filter having an arbitrary characteristic can be selected and used to some extent. Any photoelectric conversion device may be used as long as it can convert a change in light quantity into a change in electronic signal, such as a photoelectric tube, a photomultiplier tube, a photodiode, a phototransistor, or a photoconductive element.

  EXAMPLES The present invention will be specifically described below with reference to examples, but it is needless to say that the embodiments of the present invention are not limited to these examples.

(Example)
<< Preparation of Radiation Image Conversion Panel Samples 1-12 (Sample Nos. 1-12) >>
As shown below, an undercoat layer having a film thickness of 1.0 μm after drying polyester with a bar coater was applied to the surface of an aluminum plate support having a thickness of 0.5 mm (average surface roughness of 0.02 μm). And dried in hot air at 70 ° C.

  Next, a stimulable phosphor layer having a thickness of 200 μm was formed using the stimulable phosphor (CsBr: Eu) by the vapor deposition apparatus shown in FIG.

After evacuating the vacuum chamber, Ar gas is introduced and the degree of vacuum is adjusted to 1.0 × 10 ⁻² Pa and the surface temperature of the support is kept at 100 ° C. Vapor deposition was performed until the film thickness of the stimulable phosphor layer reached 400 μm to prepare a radiation image conversion panel sample.

In the vapor deposition apparatus shown in FIG. 1, the vapor deposition source is disposed on the normal line orthogonal to the center of the support, and the distance d ₁ (60 cm) between the support and the vapor deposition source is set. During the vapor deposition, the vapor deposition operation was performed while rotating the support.

  Next, the surface of the photostimulable phosphor layer is covered with a thin layer of tetrafluoroethylene-hexafluoropropylene copolymer (film thickness: 2.0 μm) as a protective layer, and the support and protective layer in an atmosphere of dry air The peripheral edge portion was sealed with an adhesive to obtain a radiation image conversion panel sample 1 having a structure in which the phosphor layer was sealed.

  Next, as shown in Table 1, the procedure was the same as that of the radiation image conversion panel sample 1 (sample No. 1) except that the excitation light reflectance of the support, the thickness of the undercoat layer, and the excitation light transmittance were changed. Radiation image conversion panel samples 2 to 12 (sample Nos. 2 to 12) were produced.

  Sample No. In order to lower the underlayer excitation light transmittance of 11 and 12, a necessary amount of carbon black was added.

  Further, in order to change the excitation light reflectance of the support surface, the average surface roughness of the support surface was slightly roughened.

<Evaluation of performance characteristics>
The following items were evaluated.

Resolution (MTF)
The sharpness was evaluated by obtaining a modulation transfer function (MTF).

  After a CTF chart was attached to each radiation image conversion panel, 80 kVp X-rays were irradiated with 10 mR (distance to the subject; 1.5 m), and then a semiconductor laser beam (690 nm, panel from the surface side having the phosphor layer A) The power was 40 mW), the CTF chart was scanned with a semiconductor laser beam having a diameter of 100 μm, and read. The values described in Table 1 are obtained as relative values for each panel, with the MTF value of the radiation image conversion panel 1 at 0.5 lp / mm being 100.

Luminance Stimulated luminescence intensity was measured.

  Evaluation is performed by irradiating the entire surface of the radiation image conversion panel with X-rays having a tube voltage of 80 kVp, scanning the panel with a 100 mW semiconductor laser (680 nm) and exciting the photoluminescence multiplier emitted from the phosphor layer. (Hamamatsu Photonics: Photomultiplier tube R1305) received light and converted into an electrical signal, analog / digital converted, and recorded on a magnetic tape.

  The recorded hard disk was analyzed with a computer, and the stimulated emission intensity was determined from the signal value of the X-ray planar image recorded on the hard disk.

  The result is Sample No. The relative value with 1 being 100 is shown.

Film-coated property The surface of the radiation image conversion panel was scratched in a lattice shape until reaching the support surface with a razor, and a cello tape (registered trademark) was pressure-bonded, peeled off rapidly, and evaluated according to a five-step peel area.

1 Adhesive strength is very weak, 100% or more area peels completely 2 2 50% or more, less than 100% peels 3 3 20% or more, less than 50% peels 4 Adhesive strength is strong 5% The area less than 20% peels off. 5 Adhesive strength is very strong, and the peeled area is less than 5% or not peeled at all. If the evaluation is 4 or more, it can be considered that the film is sufficiently strong for practical use.

  The evaluation results of the samples 1 to 12 obtained above are shown in Table 1 below.

  As is apparent from Table 1, it can be seen that the sample in the present invention is clearly superior to the sample outside the present invention (comparative).

It is the schematic which shows an example of the vapor deposition apparatus used for formation of the photostimulable phosphor layer of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Deposition apparatus 2 Vacuum chamber 3 Support body rotation mechanism (support body rotation function)
4 Support 5 Evaporation Source 6 Support Surface Temperature Control Heater

Claims (4)

Radiation in which at least an undercoat layer, a stimulable phosphor layer, and a protective layer are laminated in this order on a support, and the phosphor layer is composed of columnar crystals of an alkali halide-based stimulable phosphor In the image conversion panel, the excitation light reflectance of the support on the side of the stimulable phosphor layer is 80% or more, the excitation light transmittance of the intermediate layer is 50% or more and 100% or less, and the film thickness is 0. A radiation image conversion panel characterized by having a thickness of 1 to 10 μm. The film thickness of the undercoat layer is 0.1 to 20% with respect to the film thickness of all the constituent layers provided on the photostimulable phosphor layer side of the support. The radiation image conversion panel described. The radiation image conversion panel according to claim 1, wherein the columnar crystal of the alkali halide stimulable phosphor is composed of a CsBr columnar crystal. In the manufacturing method of the radiographic image conversion panel of any one of Claims 1-3, after applying a subbing layer on a support body and drying, forming a photostimulable phosphor layer by a vapor deposition method. A method for producing a radiation image conversion panel.

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