JP4475106B2 - Radiation image conversion panel and method for manufacturing radiation image conversion panel - Google Patents

Description

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

  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.

  As a specific method, a radiation image conversion method 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 is known (for example, patents). Reference 1).

As a radiation image conversion method using a stimulable phosphor with higher brightness and sensitivity, for example, BaFX: Eu ²⁺ system (X: Cl, Br, I) described in JP-A-59-75200 and the like. Radiation image conversion method using phosphor, radiation image conversion method using alkali halide phosphor as described in JP-A-61-72087, etc., as described in JP-A-61-73786, 61-73787, etc. In addition, alkali halide phosphors containing Tl ⁺ and Ce ³⁺ , Sm ³⁺ , Eu ³⁺ , Y ³⁺ , Ag ⁺ , Mg ²⁺ , Pb ²⁺ , and In ³⁺ metals as co-activators were developed. Has been.

  In recent years, there has been a demand for a radiation image conversion panel with higher sharpness in analysis of diagnostic images. As means for improving the sharpness, for example, attempts have been made to improve the sensitivity and sharpness by controlling the shape of the photostimulable phosphor to be formed.

  As one of these attempts, for example, a fine pseudo-columnar block formed by depositing a photostimulable phosphor on a support having a fine concavo-convex pattern, as performed in, for example, JP-A No. 61-142497 There is a method using a photostimulable phosphor layer made of

  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 was further developed by applying a shock treatment. A method of using a radiation image conversion panel having a photostimulable phosphor layer, and further a surface of the photostimulable phosphor layer formed on the surface of a support as described in JP-A-62-39737. A method using a radiation image conversion panel in which a pseudo-columnar shape is formed by cracking from the side, and further, as described in JP-A-62-110200, a photostimulable phosphor layer 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 the formation.

Furthermore, a radiation image conversion panel having a photostimulable phosphor layer in which elongated columnar crystals having a certain inclination with respect to the normal direction of the support are formed on the support by a vapor deposition method has been proposed. (For example, see Patent Document 2)
Recently, a radiation image conversion panel using a stimulable phosphor activated with Eu based on an alkali halide such as CsBr has been proposed, and in particular, high X-ray conversion that has not been obtained by using Eu as an activator. It became possible to derive efficiency.

  However, in order to form the CsBr: Eu phosphor layer, it is required to form a film by a vapor deposition method. In the formation of a deposited film, a highly accurate film thickness distribution is realized by arranging a highly accurate substrate-evaporation source in order to control the film thickness distribution and devising a physical position.

  In particular, in CsBr: Eu, diffusion of Eu due to heat is remarkable, and since the vapor pressure under vacuum is high, there is a problem that the presence of Eu in the base material is ubiquitous. It is important to the uniformity of the.

  In particular, it has a large area, and in order to increase the film thickness and improve the performance, the uniformity of adhesion between the base material and the phosphor layer is important. When a resin is present on the surface of the substrate, there are a large number of residual solvents and volatile components due to the resin production process, so that volatile components are generated during phosphor film formation, changing the degree of vacuum and causing film fluctuations.

  In the present invention, a radiation image conversion panel having excellent adhesion can be formed by making full use of the dry process in order to suppress the film fluctuation and forming a substrate surface, a phosphor layer, and a protective layer.

An object of the present invention is to improve the uniformity of manufacturing in accordance with the improvement in brightness and sharpness required from the market as a radiation image conversion panel.
US Pat. No. 3,859,527 JP-A-2-58000

  The objective of this invention is providing the manufacturing method of the radiographic image conversion panel which is excellent in the uniformity in manufacture, and shows high brightness and high sharpness, and the said radiographic image conversion panel.

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

(1)
In a radiation image conversion panel having a phosphor layer on a support, at least one phosphor layer is formed to have a film thickness of 50 μm to 20 mm by a vapor phase method (also referred to as a vapor deposition method), A radiation image conversion panel, wherein a polyurea protective film is formed on a phosphor layer by a vapor deposition process and further heat-treated, and the refractive index of the protective film on the phosphor layer is 1.61 to 1.70.
(2)
The radiation image conversion panel according to (1), wherein the phosphor is a compound represented by the following general formula (1).
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 Li, Na, K, from Rb and Cs, of at least 1 ^{M 2} is selected Li other than ^{M 1,} Na, K, from Rb and Cs M ³ is at least one trivalent selected from Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu X, X 'and X "are at least one halogen atom selected from F, Cl, Br and I, and A is Eu, Tb, In, Cs, Ce, Tm, Dy, Pr , Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, and at least one rare earth element selected from the group consisting of a, b, and e, where 0 ≦ a <0.5, 0 ≦ b <0.5, 0 <e ≦ 0.2 Represents a value.]
(3)
In a method for manufacturing a radiation image conversion panel having a phosphor layer on a support, at least one phosphor layer is formed to have a thickness of 50 μm to 20 mm by a vapor phase method (also referred to as a vapor deposition method). A polyurea protective film is formed on the phosphor layer by a vapor deposition process and further heat-treated, and the refractive index of the protective film is changed by changing the ratio of isocyanate and polyamine from aromatic to aliphatic on the phosphor layer. The manufacturing method of the radiation image conversion panel characterized by being 1.61-1.70.

  The radiation image conversion panel and the method for manufacturing the radiation image conversion panel according to the present invention are excellent in manufacturing uniformity, exhibit high brightness and high sharpness, and have excellent effects.

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

In the radiation image conversion panel having a fluorescent material layer on the support, it is formed to have a thickness of 50μm~20mm fluorescent material layer of at least one layer by a vapor phase method (also referred to as a vapor deposition) , polyurea protective film is further heat treated to form a vapor deposition process fluorescent body layer, refractive index of the fluorescent material layer on the protective film is 1. The radiation image conversion panel is 61 to 1.70 , and these objects can achieve the object of the present invention.

  The reason is not clear, but when a polyurea protective film is used, since the columnar crystals provide a light guide effect, optical continuity via the protective film between the crystals can be prevented, and the total reflection conditions The light guide effect can be obtained, which is preferable in that the effect of the present invention is further exhibited.

  Further, the refractive index can be changed from 1.2 to 2.0 by changing the ratio of isocyanate and polyamine in the polyurea protective film, from aromatic to aliphatic.

  In the present invention, a protective film is provided on the phosphor layer by a vapor deposition process.

  In the CsBr phosphor film formation, the phosphor film is formed by a vapor deposition process. The point is to form columnar crystals as crystals with excellent brightness sharpness.

  In order to increase the light light guide effect, the present inventors desirably form a columnar crystal having a good crystallinity as a columnar shape and having a tip diameter of several microns. When this columnar crystal is formed in a vacuum in a vapor deposition chamber, it is found that there is a problem that moisture is adsorbed on the surface when taken out in the air after film formation, and the performance deteriorates. When the diameter is reduced, the adsorption effect due to the capillary effect appears. In order to prevent this effect, it was found that the formation of an anti-adsorption protective film by continuous film formation is effective.

  By combining the composition ratio of polyisocyanate and polyamine and the aromatic aliphatic, it becomes possible to arbitrarily control the refractive index, and it is possible to maintain transparency while relaxing the stress.

  As the film stress relaxation method, a buffering effect can be further obtained through a heating method after completion of vapor deposition.

In the general formula (1) preferably used in the present invention, M ¹ represents at least one alkali metal atom selected from Li, Na, K, Rb and Cs, and an alkaline earth metal selected from Rb and Cs. An atom is preferred, and Cs is more preferably used.

M ³ represents a trivalent metal atom selected from Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and is preferably used among them. Is a trivalent metal atom selected from Y, Ce, Sm, Eu, Al, La, Gd, Lu, Ga and In.

  X, X ′ and X ″ are at least one halogen atom selected from F, Cl, Br and I from the viewpoint of improving the stimulated emission luminance of the phosphor, but at least one selected from F, Cl and Br A halogen atom is preferable, and a halogen atom selected from Br and I is more preferable.

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

Formula (1) represented Ru fluorescent body manufactured by the manufacturing method described below, for example.

  First, as a phosphor raw material, 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 neutral point to obtain a furnace solution The following crystals are produced by evaporating the water.

In general formula (1) (a) NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KI, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CsI
_{(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 ₂ , one or more of NiI ₂ , and (c) are Eu, Tb, In, Cs, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y An activator raw material having a metal atom selected from Tl, Na, Ag, Cu and Mg is used.

In stoichiometric fluorescent bodies Ru represented by the general formula (I), 0 ≦ a < 0.5 good, Mashiku is 0 ≦ a <0.01,0 ≦ b < 0.5, preferably 0 ≦ b ≦ 10 ⁻² , 0 <e ≦ 0.2, preferably 0 <e ≦ 0.1.

The phosphor materials (a) to (c) 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, and then water is evaporated.

  Next, the obtained raw material mixture is filled in a heat-resistant container such as a quartz crucible or an alumina crucible and fired in an electric furnace. The firing temperature is suitably 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 generally 0.5 to 6 hours is appropriate. The firing atmosphere includes a nitrogen gas atmosphere containing a small amount of hydrogen gas, a weak reducing atmosphere such as a carbon dioxide gas atmosphere containing a small amount of carbon monoxide, a neutral atmosphere such as a nitrogen gas atmosphere and an argon gas atmosphere, or a small amount of oxygen gas. A weak oxidizing atmosphere is preferred. After firing once under the above firing conditions, the fired product is taken out of 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 firing is performed, the emission luminance of the phosphor can be further increased. When the fired product is cooled to the room temperature from the firing temperature, the desired fluorescence can also be obtained by removing the fired product from the electric furnace and allowing it to cool in the 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.

Further, engagement Ru fluorescent material layer in the present invention is formed by vapor deposition (also referred to as a vapor deposition).

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

In the vapor deposition method as the first method, first, the support is installed in the vapor deposition apparatus, and then the inside of the apparatus is evacuated to a vacuum degree of about 1.333 × 10 ⁻⁴ Pa. Then, before at least one resistance heating method Kihotaru the light, the fluorescent body on the support surface by heat evaporation by a method such as electron beam method to grow to a desired thickness.

As a result, although Ihotaru light body layer such contains is formed a binder, it is also possible to form a fluorescent material layer a plurality of times in the deposition process. Further, in the above deposition step is co-deposited by using a plurality of resistance heaters or electron beams, it is also possible simultaneously to form a fluorescent material layer when synthesizing the fluorescent body shall be the object on the support.

After completion of deposition, the support side of the front Kihotaru light body layer as required radiation image conversion panel of the present invention is produced by providing a protective layer on the opposite side. Incidentally, after forming the fluorescent material layer on the protective layer may take the steps of providing a support.

Further, in the vapor deposition method, during the vapor deposition, the deposition target (support or protective layer) may be cooled or heated as necessary. Further, heating treatment may be a deposition after the completion fluorescent body layer. In the vapor deposition method, reactive vapor deposition may be 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, the support is placed in the sputtering apparatus, and then the inside of the apparatus is evacuated to a vacuum degree of about 1.333 × 10 ⁻⁴ Pa, and then for sputtering. As the gas, an inert gas such as Ar or Ne is introduced into the sputtering apparatus to obtain a gas pressure of about 1.333 × 10 ⁻¹ Pa. Next, the pre Kihotaru light body as a target, by sputtering, the fluorescent body layer is grown to a desired thickness on the support surface.

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

  There is a CVD method as a third method. A fourth method is an ion plating method.

Further, it is preferable that the growth rate of the fluorescent body layer that put the vapor deposition is 0.05 .mu.m / min ～300Myuemu / 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. A radiation image conversion panel, a vacuum deposition method described above, when obtained by a sputtering Li queuing method can increase the packing density of Phosphors in the binder is not present, the sensitivity, the preferred radiographic image on the resolution A conversion panel is obtained.

Drying thickness before Kihotaru light body layer, depending on the intended use of the radiation image conversion panel, varies depending on the type of or fluorescent body, requires a film thickness of more than 50μm from the viewpoint of obtaining the effects of the present invention Yes, preferably 50 μm to 300 mm, more preferably 100 μm to 500 μm, and particularly preferably 400 to 500 μm.

Upon manufacturing the vapor phase growth method by that fluorescent material layer, the temperature of the support fluorescent body layer is formed is preferably set to at least 100 ° C., more preferably, be 0.99 ° C. or higher Especially preferably, it is 150 to 400 degreeC.

Engaging Ru fluorescent material layer to the radiation image conversion panel of the present invention, a fluorescent body that you express by the general formula on a support (1) or the general formula (2) are formed by vapor phase growth it is preferable that the phosphor to form a columnar crystal during the layer formation.

Deposition, in order to form a columnar fluorescent material layer by a method such as sputtering, the generally formula (1) fluorescent material, such as represented by is used, it expresses by the general formula (2) Although fluorescent body is preferably used, among others, CsBr based phosphor is particularly preferably used.

Fluorescent body layer formed on a support in this manner, because does not contain a binder, has excellent directivity, high directivity of the stimulating light and stimulated luminescence, fluorescence body it is possible to increase the layer thickness from the radiographic image conversion panel having a fluorescent material layer of dispersed distributed in a binder. Further scattering in fluorescent body layer of the stimulating light is improved sharpness of an image by reducing.

Also, may be filled with a binder such as filling in the gaps between the columnar crystals, in addition to the reinforcement of the fluorescent material layer, a high light absorbing material may be filled with high light reflectance such as substances, which the addition to have a reinforcing effect, it is effective in reducing light diffusion in the lateral direction of the stimulating light incident on the fluorescent material layer by.

  A highly reflective material means a material having a high reflectivity to stimulated excitation light (500 to 900 nm, particularly 600 to 800 nm), such as white pigments and green to red regions such as aluminum, magnesium, silver, indium and other metals. The coloring material can be used.

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

  Moreover, as a substance having a high light absorption rate, for example, carbon, chromium oxide, nickel oxide, iron oxide and the like and a blue color material are used. Of these, carbon also absorbs stimulated luminescence.

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. 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 inorganic color materials include ultramarine, cobalt blue, cerulean blue, chromium oxide, and TiO ₂ —ZnO—Co—NiO pigments.

Support used for the radiation panel of the present invention As the support used for the radiation image conversion panel of the present invention, various types of glass, polymer materials, metals, etc. are used. For example, quartz, borosilicate glass, chemically tempered glass, etc. Plate glass, cellulose acetate film, polyester film, polyethylene terephthalate film, polyamide film, polyimide film, triacetate film, plastic film such as polycarbonate film, metal sheet such as aluminum sheet, iron sheet, copper sheet or the metal oxide A metal sheet having a coating layer is preferred.

It These surface of support may be glossy or may be matte for the purpose of improving the adhesion between the fluorescent material layer.

In the present invention, in order to improve the adhesion of the support and the fluorescent material layer, a pre-adhesive layer on the surface of the support may be provided as required. The thickness of these supports varies depending on the material of the support used, but is generally 80 μm to 2000 μm, and more preferably 80 μm to 1000 μm from the viewpoint of handling.

Further, engagement Ru fluorescent material layer in the present invention may have a protective layer.

  It is the schematic which shows an example of a structure of an image conversion panel.

21 in FIG. 1 is a radiation generating apparatus, 22 object, 23 a radiation image conversion panel having a visible light or infrared light fluorescent material layer containing a fluorescent body, 24 a radiation latent radiation image conversion panel 23 A photostimulated excitation light source for emitting as photostimulated luminescence, 25 is a photoelectric conversion device that detects the photostimulated luminescence emitted from the radiation image conversion panel 23, and 26 is a photoelectric conversion signal detected by the photoelectric conversion device 25 as an image. A reproducing device, 27 is a device for displaying the reproduced image, and 28 is a filter for cutting off the reflected light from the light source 24 and transmitting only the light emitted from the radiation image conversion panel. FIG. 3 shows an example of obtaining a radiation transmission image of a subject. However, when the subject 12 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 they can reproduce optical information from the radiation image conversion panel 23 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 in 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 transmission image RI is absorbed by fluorescent material layer of the radiation image conversion panel 23, the number of electrons and / or holes in proportion to the absorbed radiation dose to the fluorescent body layer is generated by the this , which are accumulated in the trap level of the fluorescent bodies. 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. That expelling electrons and / or holes stored in the trap level by irradiating fluorescent body layer by the light source 24 that emits light in the visible or infrared region, allowed to release the stored energy as stimulated emission . Intensity of the emitted stimulated light is proportional to the intensity of the accumulated electrons and / or holes having, namely fluorescent material layer to absorb the radiation energy 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, reproduced as an image by an image processing device 26, and this image is displayed by an image display device 27. It is more effective to use an image processing device 26 that can not only reproduce an electrical signal as an image signal but also so-called image processing, image calculation, image storage, storage, and the like.

Further, when excited with light energy, receives a it is necessary to separate the stimulated emission emitted from the reflected light of stimulating light and fluorescent material layer, luminescence emitted from fluorescent body layer the photoelectric converter generally the reason that the sensitivity is high for the following short-wavelength light energy 600 nm, stimulated emission emitted from the fluorescent body layer is what is desirable with a spectral distribution as possible short-wavelength region. Emission wavelength region of the fluorescent body that involved in the present invention is 300 to 500 nm, whereas since stimulating wavelength range is a 500~900nm satisfying the conditions at the same time, recently, downsizing of the diagnostic device A semiconductor laser that has a high output power and is easy to be compacted is preferably used for reading an image of the radiation image conversion panel. The wavelength of the laser light is 680 nm, and is incorporated in the radiation image conversion panel of the present invention. the fluorescent body, when using an excitation wavelength of 680 nm, shows a very good sharpness.

That is, Phosphors that involved in the present invention shows an emission having a main peak in 500nm any, to match well with the spectral sensitivity of the addition photodetector easy separation of the stimulating light can be efficiently received As a result, the sensitivity of the image receiving system can be solidified.

The stimulating light source 24, a light source including the stimulating wavelength of the fluorescent substance that is used in the radiation image conversion panel 23 is used. In particular, when a laser beam is used, the optical system becomes simple, and since the intensity of the stimulated excitation light can be increased, the photostimulated emission efficiency can be increased, and a more preferable result can be obtained.

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 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. In addition, 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 modulation using 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.

The filter 28 transmits the stimulated emission emitted from the radiation image conversion panel 23, since it is intended to cut the stimulating light, which stimulated emission of the fluorescent body you contained in the radiation image conversion panel 23 It is determined by the combination of the 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, 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. The photoelectric conversion device 25 may be any device that 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, 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 << Preparation of Radiation Image Conversion Panel Samples 1-8 (Examples 1-8) >>
Under the conditions shown in Table 1, the vapor deposition apparatus shown in FIG. 2 (provided that θ1 = 5 degrees and θ2 = 5 degrees) is provided on the surface of a 1 mm thick crystallized glass (manufactured by Nippon Electric Glass Co., Ltd.) support. A stimulable phosphor layer having a stimulable phosphor (CsBr: Eu) was used.

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

Thereafter, the inside of the vapor deposition device was once evacuated, then N ₂ gas was introduced and the degree of vacuum was adjusted to 0.133 Pa, and then vapor deposition was performed while maintaining the temperature of the support (also referred to as the substrate temperature) at about 350 ° C.

  Deposition was terminated when the thickness of the photostimulable phosphor layer reached 300 μm, and then this phosphor layer was heat-treated at a temperature of 400 ° C.

  Thereafter, a transparent protective film was formed on the phosphor layer using the vapor deposition device so as to have a refractive index shown in Table 1.

  In Examples 1 to 3, MDA (methylenediamine) was used as the polyamine, and the polyisocyanate was selected and adjusted from aliphatic isocyanates having 7 to 14 carbon atoms so as to have a predetermined refractive index.

  In Examples 4 to 8, an aliphatic polyamine HMDA (hexamethylenediamine) was used, and the polyisocyanate was selected and adjusted from aliphatic isocyanates having 7 to 14 carbon atoms so as to have a predetermined refractive index. In Example 7, an isocyanate having a silicon skeleton was used for adjustment. Table 1 shows the plate heat treatment temperature after forming the transparent protective film.

《Evaluation of sharpness》
The sharpness of the radiation image conversion panel sample was evaluated by obtaining a modulation transfer function (MTF).

  The MTF applies a CTF chart to the radiation image conversion panel sample, irradiates the radiation image conversion panel sample with 80 kVp X-rays at a distance of 10 mR (distance to the subject: 1.5 m), and then a semiconductor laser having a diameter of 100 μmφ ( 680 nm: the power on the panel was 40 mW), and the CTF chart image was scanned and read. The values in the table are MTF values of 2.0 lp / mm.

<Evaluation of luminance and luminance distribution>
The brightness was evaluated using Regius 350 manufactured by Konica Minolta.

  As in the sharpness evaluation, X-rays were irradiated with a tungsten tube at 80 kVp and 10 mAs at a distance of 2 m between the bombardment source and the plate, and then a plate was set on the Regius 350 and read. Relative evaluation was performed based on the electrical signal from the obtained photomultiplier. The luminance of Sample 2 was set to 1.0, and the subsequent values were expressed as relative values.

  The electrical signal distribution from the photographed in-plane photomultiplier was relatively evaluated, the standard deviation was obtained, and the luminance distribution (SD) of each sample was obtained.

  When each of the above evaluations is good, the activator is uniformly contained in the phosphor base crystal.

Schematic which shows an example of a structure of the radiation image conversion panel of this invention. Schematic which shows an example of the method of producing a stimulable fluorescent substance layer on a support body by vapor deposition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Support body 12 Stimulable fluorescent substance layer 13 Columnar crystal 14 The 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 It was radiated | emitted by this conversion panel Photoelectric conversion device for detecting photostimulated fluorescence 26 Image reproduction device 27 Image display device 28 Filter

Claims (3)

In a radiation image conversion panel having a phosphor layer on a support, at least one phosphor layer is formed to have a film thickness of 50 μm to 20 mm by a vapor phase method (also referred to as a vapor deposition method), A radiation image conversion panel, wherein a polyurea protective film is formed on a phosphor layer by a vapor deposition process and further heat-treated, and the refractive index of the protective film on the phosphor layer is 1.61 to 1.70. The radiation image conversion panel according to claim 1, wherein the phosphor is a compound represented by the following general formula (1).
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 Li, Na, K, from Rb and Cs, of at least 1 ^{M 2} is selected Li other than ^{M 1,} Na, K, from Rb and Cs M ³ is at least one trivalent selected from Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu X, X 'and X "are at least one halogen atom selected from F, Cl, Br and I, and A is Eu, Tb, In, Cs, Ce, Tm, Dy, Pr , Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, and at least one rare earth element selected from the group consisting of a, b, and e, where 0 ≦ a <0.5, 0 ≦ b <0.5, 0 <e ≦ 0.2 Represents a value.] In a method for manufacturing a radiation image conversion panel having a phosphor layer on a support, at least one phosphor layer is formed to have a thickness of 50 μm to 20 mm by a vapor phase method (also referred to as a vapor deposition method). A polyurea protective film is formed on the phosphor layer by a vapor deposition process and further heat-treated, and the refractive index of the protective film is changed by changing the ratio of isocyanate and polyamine from aromatic to aliphatic on the phosphor layer. The manufacturing method of the radiation image conversion panel characterized by being 1.61-1.70.

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