JP2008180627A - Radiation image conversion panel, method for manufacturing it and radiography system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation image conversion panel which has high intensity and is excellent in the adhesiveness of a stimulable phosphor layer, and to provide a method for manufacturing the panel. <P>SOLUTION: In the radiation image conversion panel where a phosphor layer is set up on a substrate; the radiation image conversion panel, the method for manufacturing it and a radiography system are characterized in that the phosphor layer is made mainly of columnar crystal phosphors, and in that some phosphors get into the uppermost surface of the substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radiation image conversion panel using a photostimulable phosphor and a method for producing the same, and more particularly to a radiation image conversion panel excellent in adhesiveness of a stimulable phosphor layer and a method for producing the same.

  Radiation images such as X-ray images are often used in fields such as disease diagnosis. The X-ray image is obtained by irradiating the phosphor layer (phosphor screen) with X-rays that have passed through the subject, thereby generating visible light, and then using this visible light as when taking a normal photograph. Thus, a so-called radiographic method in which a silver halide photographic light-sensitive material (hereinafter also simply referred to as a light-sensitive material) is irradiated and then developed to obtain a visible silver image is widely used.

  However, in recent years, a new method for taking out an image directly from a phosphor layer has been proposed instead of an image forming method using a photosensitive material having a silver halide salt.

  In this method, the radiation transmitted through the subject is absorbed by the phosphor, and then the phosphor is excited by, for example, light or heat energy, so that the radiation energy accumulated by the phosphor is absorbed as fluorescence. There is a method of emitting and detecting this fluorescence and imaging.

  Specifically, a radiation image conversion method using a stimulable phosphor (hereinafter also simply referred to as a phosphor) is known (for example, see Patent Documents 1 and 2).

  This method uses a radiation image conversion panel containing a photostimulable phosphor. The radiation transmission density of each part of the subject is obtained by applying radiation transmitted through the subject to the photostimulable phosphor layer of the radiation image conversion panel. Is stored in the stimulable phosphor by chronologically exciting the stimulable phosphor with electromagnetic waves (excitation light) such as visible light and infrared light. Radiation energy is emitted as stimulated emission, and a signal based on the intensity of the light is photoelectrically converted to obtain an electrical signal, which is then used as a recording material such as a silver halide photographic material, or a display device such as a CRT. It is reproduced as a visible image on the top.

  According to the above radiographic image reproduction method, it is possible to obtain a radiographic image with a much smaller exposure dose and abundant information as compared with the radiographic method using a combination of a conventional radiographic film and an intensifying screen. Has the advantage of being able to

  Radiation image conversion panels using these photostimulable phosphors release accumulated energy by scanning excitation light after accumulating radiation image information, so that radiation images can be accumulated again after scanning. Can be used. In other words, the conventional radiographic method consumes a radiographic film for each photographing, whereas this radiographic image conversion method repeatedly uses a radiographic image conversion panel, so that also from the viewpoint of resource protection and economic efficiency. It is advantageous.

  Further, in recent years, a higher-definition radiation image conversion panel is required for analysis of diagnostic images. As means for improving the sharpness, for example, an attempt has been made to improve the sensitivity and sharpness by controlling the shape of the photostimulable phosphor to be formed.

  As one of these attempts, it has a stimulable phosphor layer in which elongated columnar crystals having a certain inclination with respect to the normal direction of the substrate are formed on the substrate by vapor deposition (vapor deposition). A method using a radiation image conversion panel (see Patent Document 3) has been proposed.

  Recently, a radiation image conversion panel using a stimulable phosphor using Eu as an activator with an alkali halide such as CsBr as a base has been proposed, and it is possible to derive a high X-ray conversion efficiency that has not been obtained so far. It became.

  However, even in the radiation image conversion panel having the photostimulable phosphor layer formed by vapor phase growth (deposition), the sharpness required from the market is not sufficiently improved, and further improvement has been demanded.

  In radiation image conversion panels used under various conditions, the adhesion between the substrate and the phosphor layer is one of the important characteristics, and an undercoat resin layer containing a crosslinking agent is provided between the substrate and the phosphor layer. Although a method of providing is disclosed (see Patent Documents 4 to 6), simply forming an undercoat resin layer, when forming a photostimulable phosphor layer on the undercoat resin layer by the vapor phase growth method, When the surface of the undercoat resin layer is uneven, the adhesion to the substrate is poor and the crystal structure in the phosphor layer becomes uneven, resulting in variations in sharpness and irregularities in the radiation image conversion panel. There was a thing. In addition, the film thickness of the undercoat resin layer may be too large, and the temporal stability of characteristics may be reduced.

Thus, in the radiation image conversion panel, development of a radiation image conversion panel excellent in sharpness, stability of characteristics over time, and adhesion of the stimulable phosphor layer to the substrate is desired.
US Pat. No. 3,859,527 Japanese Patent Laid-Open No. 55-12144 JP-A-2-58000 Japanese Patent Publication No. 4-44959 JP 2005-91222 A JP 2006-125854 A

  An object of the present invention is to provide a radiation image conversion panel having high brightness and excellent adhesion of a stimulable phosphor layer and a method for producing the same.

  The above object of the present invention can be achieved by the following configuration.

  1. In the radiation image conversion panel in which the phosphor layer is disposed on the substrate, the phosphor layer is mainly formed of a columnar crystal phosphor, and a part of the phosphor enters the outermost surface of the substrate. Characteristic radiographic image conversion panel.

  2. 2. The radiation image conversion panel as described in 1 above, wherein the substrate is an organic resin.

  3. 3. The radiation image conversion panel according to 2 above, wherein the substrate is provided with a base layer having a thickness of 0.1 μm to 10 μm made of an organic resin having a Tg of 30 ° C. to 120 ° C.

  4). 4. The radiation image conversion panel according to any one of 1 to 3, wherein the phosphor is a stimulable phosphor.

  5. 5. The radiation image conversion panel according to any one of 1 to 4, wherein the phosphor is a phosphor having CsBr as a base material.

  6). The radiation image conversion panel according to any one of 1 to 5, wherein the temperature of the substrate is equal to or higher than the lower one of the softening temperature or the melting temperature of the base layer of the substrate or the underlayer processed on the surface of the substrate. The manufacturing method of the radiographic image conversion panel characterized by manufacturing by controlling vapor deposition and performing vapor deposition.

  7. 7. The method for producing a radiation image conversion panel according to claim 6, wherein the heating of the substrate is performed by heating from the back surface of the substrate to control the temperature and vapor deposition.

  8). An X-ray imaging system, wherein the radiation image conversion panel according to any one of 1 to 5 is disposed in a portable container, X-rays are exposed, and reading is performed.

  According to the present invention, it was possible to provide a radiation image conversion panel having high luminance and excellent adhesion to a stimulable phosphor layer and a method for producing the same.

  The present invention will be described in more detail.

〔substrate〕
The board | substrate of the radiographic image conversion panel used for this invention is demonstrated.

  As the substrate used in the radiation image conversion panel of the present invention, various glasses, polymer materials, metals, etc. are used. For example, plate glass such as quartz, borosilicate glass, chemically tempered glass, cellulose acetate film, polyester, etc. Examples include films, polyethylene terephthalate films, polyamide films, polyimide films, triacetate films, polycarbonate resin and other organic resin films, metal sheets such as aluminum sheets, iron sheets, and copper sheets, or metal sheets having a coating layer of the metal oxide. . Among these, an organic resin film is preferable. The organic resin film is controlled by controlling the substrate temperature above the softening point, so that the deposited crystal can enter the substrate. Further, the amount of penetration can be controlled not only by the substrate temperature but also by the vapor incidence speed, vapor temperature, and the like. These incident speeds and temperatures can be controlled by the temperature at which the deposition material is evaporated. When a metal or glass substrate is selected, it is necessary to provide the underlayer shown below.

[Underlayer]
In the present invention, it is preferable to provide an underlayer between the substrate and the photostimulable phosphor layer.

  The resin that can be used in the underlayer is not particularly limited. For example, polyvinyl alcohol, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester resin, polyethylene terephthalate, polyethylene, nylon, (meth) acrylic acid, or (meth) Acrylic acid esters, vinyl esters, vinyl ketones, styrenes, diolefins, (meth) acrylamides, vinyl chlorides, vinylidene chlorides, cellulose derivatives such as nitrocellulose, acetylcellulose, diacetylcellulose, silicone resins, polyurethane resins , Polyamide resins, various synthetic rubber resins, phenol resins, epoxy resins, urea resins, melamine resins, phenoxy resins, and the like. Of these, hydrophobic resins such as polyester resins and polyurethane resins are preferable from the viewpoints of adhesion between the substrate and the photostimulable phosphor layer and corrosion resistance of the substrate.

  The film thickness of the underlayer in the present invention is 0.1 to 10 μm, more preferably 1 to 5 μm. If the film thickness of the underlayer is less than 0.1 μm, the adhesive force between the substrate and the photostimulable phosphor layer may be weak, and if it exceeds 10 μm, the temporal stability of quality such as sharpness may be lowered.

  As a measuring device, for example, it can be measured by a known surface roughness measuring method such as a stylus method or laser interferometry.

  In addition to the resin, the underlayer according to the present invention may contain a crosslinking agent in order to impart film strength. There is no restriction | limiting in particular as a crosslinking agent which can be used, For example, a polyfunctional isocyanate and its derivative (s), a melamine and its derivative (s), an amino resin, and its derivative (s) etc. can be mentioned, A polyfunctional isocyanate compound is preferable. Examples of the polyfunctional isocyanate compound include Coronate HX and Coronate 3041 manufactured by Nippon Polyurethane.

  The amount of the crosslinking agent used varies depending on the characteristics of the intended radiation image conversion panel, the type of stimulable phosphor layer and the material used for the substrate, the type of resin used for the underlayer, etc. Considering the maintenance of the adhesive strength with the substrate, it is preferably 50% by mass or less, more preferably 5 to 30% by mass with respect to the undercoat resin. If it is less than 5% by mass, the crosslinking density is low, and both heat resistance and strength are insufficient. When it exceeds 30% by mass, the crosslinking density is high, the toughness with the underlayer is lowered (becomes brittle), and the underlayer is cracked.

  In the present invention, after coating the base layer on the substrate, before coating the photostimulable phosphor layer, in order to complete the reaction between the resin in the base layer and the crosslinking agent, the temperature is 1 to 40 to 150 ° C. Heat treatment is performed for 100 hours.

  The underlayer is obtained by applying and drying an underlayer coating liquid on the substrate. The coating method is not particularly limited, and a known coating coater such as a doctor blade, a roll coater, a knife coater, or an extrusion coater may be used, or a spin coater may be used.

[Stimulable phosphor]
The photostimulable phosphor of the present invention will be described. The phosphor of the present invention is preferably a stimulable phosphor, particularly preferably a stimulable phosphor represented by the following general formula (1).

General formula (1)
M ¹ X · aM ² X ′ ₂ : eA, A ″
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, X and X ′ are at least one halogen atom selected from each atom of F, Cl, Br and I, and A and A ″ are Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm and Y are at least one rare earth atom, and a and e are each 0 ≦ a <0.5 and 0 <e ≦ 0.2 in the range of numerical values.

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

M ² represents at least one divalent metal atom selected from the atoms of Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu, and Ni. Among these, Be, Mg, It is a divalent metal atom selected from each atom such as Ca, 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. This represents a trivalent metal atom, but among them, a trivalent metal atom selected from each atom such as Y, Ce, Sm, Eu, Al, La, Gd, Lu, Ga, and In is preferable. .

  A is at least selected from each atom of Eu, Tb, In, Ga, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu, and Mg. One kind of metal atom.

  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.

In the general formula (1), b represents 0 ≦ b <0.5, and preferably 0 ≦ b ≦ 10 ⁻² .

  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,
(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 or two or more compounds selected from ₂ and NiI ₂ compounds are 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.

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.

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

  As a vapor phase growth method of the photostimulable phosphor, an evaporation method, a sputtering method, a CVD method, an ion plating method, and other methods can be used.

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

In the first vapor deposition method, first, a substrate is placed in a vapor deposition apparatus, and then 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 phosphors is heated and evaporated by a resistance heating method, an electron beam method, or the like to grow the photostimulable phosphor on the substrate surface 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 also possible to co-evaporate using a plurality of resistance heaters or electron beams to synthesize the desired stimulable phosphor on the substrate and simultaneously form the stimulable phosphor layer. .

  It is preferable to manufacture the radiation image conversion panel of the present invention by providing a protective layer on the side opposite to the substrate side of the photostimulable phosphor layer, if necessary, after completion of vapor deposition. In addition, after forming a photostimulable phosphor layer on a protective layer, a procedure of providing a substrate may be taken.

  Furthermore, in the vapor deposition method, it is preferable to heat an object to be vapor-deposited (substrate, protective layer or intermediate layer) as needed during vapor deposition. By performing vapor deposition at a temperature higher than the softening temperature of the substrate or the undercoat layer, a phosphor layer having a desired shape can be obtained.

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, as in the vapor deposition method, a substrate having a protective layer or an intermediate layer is placed in a sputtering apparatus, and then the apparatus is evacuated to a vacuum of about 1.333 × 10 ⁻⁴ Pa. Then, an inert gas such as Ar or Ne is introduced as a sputtering gas into the sputtering apparatus to obtain a gas pressure of about 1.333 × 10 ⁻¹ Pa. Next, a stimulable phosphor layer is grown on the substrate 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 stimulable phosphor can be increased, and preferable radiation image conversion in terms of sensitivity and resolution. A panel is obtained and preferred.

  The film thickness of the photostimulable phosphor layer is preferably 50 to 1000 μm from the viewpoint of obtaining the effects of the present invention, although it varies depending on the purpose of use of the radiation image conversion panel and the type of stimulable phosphor. More preferably, it is 100-600 micrometers, More preferably, it is 100-500 micrometers.

  In the production of the photostimulable phosphor layer by the vapor phase growth method, the temperature of the substrate on which the photostimulable phosphor layer is formed is the softening temperature of the base material of the substrate or the base layer processed on the substrate surface, or It is preferable to carry out by controlling the temperature of the substrate above the lower melting temperature. Furthermore, it is preferable to perform evaporation by controlling the temperature by heating the substrate from the back side of the substrate.

  The photostimulable phosphor layer of the radiation image conversion panel of the present invention is preferably formed by vapor-phase growth of the photostimulable phosphor represented by the general formula (1) on the substrate. More preferably, the stimulable phosphor forms a columnar crystal.

  In order to form a columnar stimulable phosphor layer by a method such as vapor deposition or sputtering, the compound represented by the general formula (1) (stimulable phosphor) is used. The CsBr phosphor represented by 2) is particularly preferably used.

General formula (2)
CsX: A
In the general formula (2), X represents Br or I, and A represents Eu, In, Tb, Tl, or Ce.

  As a method of forming a phosphor layer on a substrate by a vapor deposition method, an elongated columnar crystal independent by a vapor deposition (deposition) method such as vapor deposition by supplying a vapor of a stimulable phosphor or the raw material, is used. A photostimulable phosphor layer made of can be obtained. In these cases, it is preferable that the distance between the shortest part between the substrate and the crucible is usually set to 10 to 60 cm in accordance with the average range of the stimulable phosphor.

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

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

  Moreover, you may dope an activator afterwards with respect to the base material of fluorescent substance. For example, after depositing only CsBr as a base material, Tl as an activator may be doped. That is, since the crystals are independent, even if the film is thick, it can be sufficiently doped, and crystal growth hardly occurs, so the MTF does not decrease.

White pigments can also reflect stimulated emission. As white pigments, 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 At least one of Ca, and X is at least one of Cl and Br.), CaCO ₃ , ZnO, Sb ₂ O ₃ , SiO ₂ , ZrO ₂ , lithopone (BaSO ₄ .ZnS), silicic acid Examples include magnesium, basic silicic acid sulfate, basic lead phosphate, and aluminum silicate. 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.

  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 (manufactured by Orient), Kitten Blue A (manufactured by Ciba Geigy), Eisen Cachiron Blue GLH (manufactured by Hodogaya Chemical), Lake Blue AFH (manufactured by Kyowa Sangyo), Primocyanin 6GX (manufactured by Inabata Sangyo), Brill Acid Green 6BH (manufactured by Hobo Tsuchiya Chemical Co., Ltd.), Cyan Blue BNRCS (Toyo Ink), Lionoyl Blue SL (Toyo Ink) and the like are used. 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 inorganic color materials include ultramarine blue, cobalt blue, cerulean blue, chromium oxide, and TiO ₂ —ZnO—Co—NiO pigments.

  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, a vapor deposition apparatus as shown in FIG. 1 is typically 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]
Moreover, the photostimulable phosphor layer of the present invention may have a protective layer.

The protective layer may be formed by directly applying a coating solution for the protective layer on the photostimulable phosphor layer, or a protective layer separately formed in advance may be adhered on the photostimulable phosphor layer. Or you may take the procedure of forming a photostimulable phosphor layer on the protective layer formed separately. 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-ethylene chloride Ordinary protective layer materials such as tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer are used. In addition, a transparent glass substrate can be used as the protective layer. Further, this protective layer may be formed by laminating inorganic substances such as SiC, SiO ₂ , SiN, Al ₂ O ₃ by vapor deposition, sputtering, or the like. The thickness of these protective layers is generally preferably about 0.1 to 2000 μm.

  In the present invention, the laser diameter irradiated to the photostimulable phosphor layer is preferably 100 μm or less, more preferably 80 μm or less.

As the laser, the He-Ne laser, the He-Cd laser, Ar ion laser, Kr ion laser, N ₂ laser, YAG laser and its second harmonic, ruby laser, semiconductor lasers, various dye lasers, copper vapor laser, etc. There are metal vapor 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, a pulsed laser is used rather than modulation using a continuous wave laser. Is preferred.

  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.

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

Example 1
<< Radiation image conversion panel sample No. Preparation of 1-16 >>
(Production of substrate Nos. 8 to 16)
Sample No. shown in Table 1 For the substrates described in 8 to 16, a polyester resin (Byron series manufactured by Toyobo Co., Ltd.) or an epoxy resin (UCC Co.) having a Tg or melting temperature shown in Table 1 as an undercoat layer is 1 / (methyl ethyl ketone / toluene). The undercoat layer coating solution dissolved in a 1 mass ratio mixed solvent was applied with a wire bar coater and dried in hot air at 70 ° C. By the above operation, the radiation image conversion panel sample No. 8 to 16 substrates were obtained.

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

After evacuating the inside of the vacuum chamber, Ar gas was introduced and the degree of vacuum was adjusted to 1.0 × 10 ⁻² Pa, while maintaining the substrate surface temperature at 100 ° C. Until the film thickness of the fluorescent layer becomes 400 μm, the radiation image conversion panel sample No. 1-5 and 8-16 were produced.

  Radiation image conversion panel sample No. For 6 and 7, first, the surface temperature of the aluminum substrate was set to 25 ° C. as a subtraction of the filling rate, and an undercoated phosphor layer having the thickness shown in Table 1 was obtained. Then, the substrate temperature was increased again to 100 ° C. While maintaining the thickness of the photostimulable phosphor layer until the thickness of the photostimulable phosphor layer becomes 400 μm. 6 and 7 were produced.

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 Radiation image conversion panel sample No. 1 having a structure in which the periphery is sealed with an adhesive and the phosphor layer is sealed. 1-16 were obtained.

(Evaluation methods)
・ Luminance (stimulated luminescence intensity)
The obtained radiation image conversion panel was set in a cassette (portable container) for REGIUS190 manufactured by Konica Minolta MG Co., Ltd., X-ray with a tube voltage of 80 kVp was irradiated on the entire surface, and data was read using REGIUS190. The stimulated emission intensity was determined from the signal value of the obtained data. The result is Sample No. The relative values with 1 being 100 are shown in Table 1.

-Vibration test The obtained radiation image conversion panel was affixed on a carbon fiber plate having a thickness of 5 mm and subjected to vibration at 100 Hz and a displacement of 5 mm for 1 hour. The sample subjected to vibration is irradiated with X-rays with a tube voltage of 80 kVp, the panel is scanned with a 100 mW semiconductor laser (680 nm) and excited, and the stimulated emission emitted from the phosphor layer is photomultiplier tube (Hamamatsu Photonics). Manufactured by photomultiplier tube R1305), converted into an electrical signal, converted from analog to digital, and stored in a hard disk. Hard disk data was evaluated on a computer monitor. Evaluation was carried out in the following five stages, and the results are shown in Table 1.

1: The phosphor layer cannot be used due to many cracks and peeling. 2: The phosphor layer has cracks and peeling. 3: The phosphor layer has few cracks and peeling. 4: The phosphor layer has some cracks and peeling. However, it can be used. 5: There is no cracking or peeling of the phosphor layer.

-Drop test The obtained radiation image conversion panel was affixed on a carbon fiber plate having a thickness of 5 mm, and a natural drop test was performed 50 times from a height of 75 cm with the phosphor layer facing upward. X-ray with a tube voltage of 80 kVp is irradiated from a position 100 cm away to a sample subjected to drop vibration, and the panel is excited by scanning with a 100 mW semiconductor laser (680 nm), and the stimulated emission emitted from the phosphor layer is photoelectron. Light was received using a multiplier tube (manufactured by Hamamatsu Photonics: photomultiplier tube R1305), converted into an electrical signal, analog / digital converted, and stored in a hard disk. Hard disk data was evaluated on a computer monitor. Evaluation was carried out in the following five stages, and the results are shown in Table 1.

1: The phosphor layer cannot be used due to many cracks and peeling. 2: The phosphor layer has cracks and peeling. 3: The phosphor layer has few cracks and peeling. 4: The phosphor layer has some cracks and peeling. Yes 5: There is no cracking or peeling of the phosphor layer.

  From the table, it can be seen that the radiation image conversion panel of the present invention is superior in peelability, sharpness, and sharpness over time as compared with the comparative example.

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 (8)

In the radiation image conversion panel in which the phosphor layer is disposed on the substrate, the phosphor layer is mainly formed of a columnar crystal phosphor, and a part of the phosphor enters the outermost surface of the substrate. Characteristic radiographic image conversion panel. The radiation image conversion panel according to claim 1, wherein the substrate is an organic resin. The radiation image conversion panel according to claim 2, wherein the substrate is provided with an underlayer having a thickness of 0.1 μm or more and 10 μm or less made of an organic resin having a Tg of 30 ° C. or more and 120 ° C. or less. The radiation image conversion panel according to claim 1, wherein the phosphor is a stimulable phosphor. The radiation image conversion panel according to claim 1, wherein the phosphor is a phosphor having CsBr as a base material. The radiation image conversion panel according to any one of claims 1 to 5, wherein the base material of the substrate or the underlayer processed on the surface of the substrate has a softening temperature or a melting temperature equal to or higher than a lower temperature. A method for producing a radiation image conversion panel, comprising producing by controlling temperature and performing vapor deposition. The method for manufacturing a radiation image conversion panel according to claim 6, wherein the substrate is heated by heating from the back surface of the substrate to control the temperature and vapor deposition is performed. An X-ray imaging system, wherein the radiation image conversion panel according to any one of claims 1 to 5 is disposed in a portable container, X-rays are exposed, and reading is performed.

Images