JP2005164493A - Radiation image conversion panel and manufacturing method of radiation image conversion panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation image conversion panel with high sensitivity, high uniformity, exfoliation durability and shock resistivity, and a manufacturing method for the radiation image conversion panel. <P>SOLUTION: The radiation image conversion panel is provided with a stimulable phosphor layer 12 containing stimulable phosphor on a support 11 by gas deposition. The filling factor distribution of the stimulable phosphor layer 12 is ±10% or less. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a radiation image conversion panel provided with a stimulable phosphor layer containing a stimulable phosphor on a support by a vapor deposition method, and a method for producing the radiation image conversion panel.

Conventionally, so-called radiography using a silver salt is 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 stimulable phosphor, and then the stimulable phosphor is excited with a certain energy to excite the radiation energy accumulated in the stimulable phosphor. A method of emitting as a fluorescent material and detecting and imaging this fluorescence 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 (Patent Document 1). reference).

By the way, in recent years, as a radiation image conversion method using a high-luminance, high-sensitivity, high-sharp photostimulable phosphor, radiation using a photostimulable phosphor activated with Eu based on an alkali halide such as CsBr. An image conversion panel has been proposed. In particular, by using Eu as an activator, X-ray conversion efficiency, which has been impossible in the past, can be improved.
JP 2001-249198 A

However, as described in the above-mentioned Patent Document 1, an AX phosphor in which Eu or the like is activated on an alkali halide base such as CsBr has a large coefficient of thermal expansion, and peels from the support when the crystallinity is increased. It tends to be easier and impact resistance is also reduced. For this reason, in addition to high sensitivity and high uniformity, the photostimulable phosphor layer is required to have improved peeling durability and impact resistance.
The present invention has been made in view of the above circumstances, and provides a radiation image conversion panel excellent in peeling durability and impact resistance in addition to high sensitivity and high uniformity, and a method for manufacturing a radiation image conversion panel. The purpose is that.

In order to solve the above problems, the invention of claim 1 is a radiation image conversion panel comprising a photostimulable phosphor layer containing a photostimulable phosphor on a support by a vapor deposition method.
The filling rate distribution of the photostimulable phosphor layer is ± 10% or less.

  According to the invention of claim 1, since the filling rate distribution of the stimulable phosphor layer is ± 10% or less, the filling rate distribution is substantially uniform in the plane, and the warpage of the panel can be further reduced. In addition to high sensitivity and high uniformity, it has excellent peeling durability and impact resistance. Therefore, the image quality of the radiation image can be improved.

The invention of claim 2 is the radiation image conversion panel according to claim 1,
The filling rate distribution of the photostimulable phosphor layer is isotropically changed from the center of the support toward the end.

  According to the invention of claim 2, since the filling rate distribution of the photostimulable phosphor layer isotropically changes from the center of the support toward the end, the stress distribution resulting from the filling rate distribution is also the same. Can be distributed evenly and evenly. Therefore, the warpage of the panel can be reduced, and in addition to high sensitivity and high uniformity, it is possible to have excellent peeling durability and impact resistance.

The invention of claim 3 is the radiation image conversion panel according to claim 1 or 2, wherein the photostimulable phosphor layer is based on an alkali halide represented by the following general formula (1). It contains a phosphor.
M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : eA (1)
[Wherein, M ¹ is at least one alkali metal atom selected from Li, Na, K, Rb and Cs atoms, and M ² is Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu. And at least one divalent metal atom selected from each atom of Ni, and M ³ is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, At least one trivalent metal atom selected from each atom of Tm, Yb, Lu, Al, Ga and In, and X, X ′ and X ″ are at least selected from each atom of F, Cl, Br and I 1 type of halogen atom, A is Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg. At least one metal atom selected from each atom, and a, b, e each represent a number between 0 ≦ a <0.5,0 ≦ b <0.5,0 <e <1.0.]

  According to the invention of claim 3, since the photostimulable phosphor layer is based on the alkali halide represented by the general formula (1), the photostimulable phosphor layer having both high sensitivity and high sharpness. And the image quality of the radiation image can be significantly improved.

According to a fourth aspect of the present invention, there is provided a vacuum vessel, an evaporation source provided in the vacuum vessel for depositing a stimulable phosphor on a support, and supporting the support and rotating with respect to the evaporation source. The radiation image conversion panel as described in any one of Claims 1-3 is manufactured using the vapor deposition apparatus provided with the support body rotation mechanism which vapor-deposits the stimulable fluorescent substance from this evaporation source by this A method for manufacturing a radiation image conversion panel, comprising:
The stimulable phosphor layer evaporating from the evaporation source is deposited on the support by supporting and rotating the support by the support rotating mechanism to form a stimulable phosphor layer. Features.

According to the invention of claim 4, by supporting and rotating the support by the support rotating mechanism, the stimulable phosphor that evaporates from the evaporation source is deposited on the support to form the stimulable phosphor layer. As a result, the photostimulable phosphor layer is uniformly formed on the support.
In addition, since the photostimulable phosphor is deposited by rotating the support, the residual stress remaining during the deposition is uniformly dispersed, and the warpage of the panel can be further reduced, and the sensitivity and uniformity are high. In addition to the properties, it has excellent peeling durability and impact resistance. Therefore, the image quality of the radiation image can be improved.

According to the radiation image conversion panel and the method for manufacturing a radiation image conversion panel according to the present invention, since the filling rate distribution of the stimulable phosphor layer is ± 10% or less, the filling rate distribution is substantially uniform. Since warpage can be further reduced, in addition to high sensitivity and high uniformity, it is excellent in peeling durability and impact resistance. Therefore, the image quality of the radiation image can be improved.
In addition, by changing the filling rate distribution isotropically from the center of the support to the edge, the stress distribution becomes uniform and the warpage of the panel can be further reduced, in addition to high sensitivity and high uniformity. It can be made very excellent in peeling durability and impact resistance.

Hereinafter, the radiation image conversion panel and the method for manufacturing the radiation image conversion panel according to the present invention will be described in detail.
As shown in FIG. 1, the radiation image conversion panel of the present invention includes a support 11 and a stimulable phosphor layer 12 formed on the support 11 and containing a stimulable phosphor. Moreover, the protective layer which protects the photostimulable phosphor layer 12 is provided as needed. In the photostimulable phosphor layer 12, a gap 14 is formed between the columnar crystals 13 of the photostimulable phosphor.

The present inventors have found that by setting the filling rate distribution of the photostimulable phosphor layer to ± 10% or less, it is possible to improve the sensitivity, high uniformity, peel durability, and impact resistance. .
The filling rate and filling rate distribution are measured as follows.
(Filling rate measurement method)
The photostimulable phosphor layer is cut out with a size of Acm × Acm, the film thickness B (cm) is measured with a micrometer, and the weight C (gr) is measured with a balance. When the specific gravity of CsBr is ρ (= 4.43),
Filling rate D = C / (A ⁻² × B × ρ)
(Filling rate distribution measurement method)
Thirty photostimulable phosphor layers are cut out from one radiation image conversion panel, and the filling rate D is calculated for each. When the maximum filling rate is Dmax and the minimum filling rate is Dmin,
Filling rate distribution (%) = ((Dmax−Dmin) / (Dmax + Dmin)) × 100

Here, the reason why the filling rate distribution is defined as ± 10% or less is that when it exceeds ± 10%, the filling rate distribution becomes non-uniform and the panel tends to warp. As a result, uneven sensitivity and peeling occur, and impact resistance decreases.
The filling rate of the photostimulable phosphor layer can be controlled, for example, by changing the degree of vacuum during vapor deposition to 10 ⁻⁴ Pa to 1.0 Pa, or by changing the distance between the support and the evaporation source. it can.

Moreover, it is preferable that the filling rate distribution of the stimulable phosphor layer isotropically changes from the center of the support toward the end. By making the filling rate distribution isotropic in this way, the stress distribution resulting from the filling rate distribution can be isotropically and evenly distributed, the panel warpage can be reduced, and high sensitivity and high uniformity can be achieved. In addition, a panel having excellent peeling durability and target dramatic performance can be obtained.
Note that the filling rate distribution isotropically changed from the center of the support toward the end, as shown in FIG. 5 (a), the filling is on a substantially concentric circle (approximately the same distance from the center of the support). This means that the rate distribution is approximately equal. On the other hand, anisotropic means a state in which the filling rate distribution on the line shown in FIG. 5 (b) or (c) is equal, and is substantially concentric from the center of the support. It means that the filling rate distribution above is not equal.

The support used in the present invention can be arbitrarily selected from known materials as a support for a conventional radiation image conversion panel. However, in the case of forming a phosphor layer by a vapor deposition method, In particular, a quartz glass sheet, a metal sheet made of aluminum, iron, tin, chromium, or the like, and a carbon fiber reinforced sheet are preferable.
The support preferably has a resin layer in order to make the surface smooth.
The resin layer preferably contains a compound such as polyimide, polyethylene terephthalate, paraffin, graphite, and the film thickness is preferably about 5 μm to 50 μm. This resin layer may be provided on the front surface, the back surface, or both surfaces of the support.
Examples of means for providing the resin layer on the support include means such as a bonding method and a coating method.
Bonding is performed using heating and a pressure roller, and the heating condition is preferably about 80 to 150 ° C., the pressing condition is 4.90 × 10 to 2.94 × 10 ² N / cm, and the conveyance speed is 0. .1 to 2.0 m / sec is preferable.

  The film thickness of the photostimulable phosphor layer of the present invention is 50 μm to 2000 μm from the viewpoint of obtaining the effects of the present invention, although it varies depending on the intended use of the radiation image conversion panel and the type of stimulable phosphor. Preferably they are 50 micrometers-1000 micrometers, More preferably, they are 100 micrometers-800 micrometers.

The stimulable phosphor layer preferably contains a stimulable phosphor 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 from Li, Na, K, Rb and Cs atoms; ² is at least one divalent metal atom selected from the atoms of Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu and Ni, and M ³ is Sc, Y, La, Ce, Pr, Nd. , Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In, at least one trivalent metal atom, and X, X ′, X ″ is at least one halogen atom selected from F, Cl, Br, and I atoms, and A is Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd , Lu, Sm, Y, Tl, Na, Ag, Cu and Mg It is at least one kind of metal atom, and a, b and e each represent a numerical value in the range of 0 ≦ a <0.5, 0 ≦ b <0.5, and 0 <e ≦ 0.2. ]

In the photostimulable phosphor represented by the general formula (1), M ¹ 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 these, Be, It is a divalent metal atom selected from each atom such as Mg, Ca, Sr and Ba.

M ³ is selected from atoms such as Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In. At least one trivalent metal atom is represented, 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. It is.

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

  From the viewpoint of improving the photostimulable emission luminance of the photostimulable phosphor, X, X ′ and X ″ 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), the b value is 0 ≦ b <0.5, and preferably 0 ≦ b <10 ⁻² .

In particular, in the present invention, it is preferable to use a stimulable phosphor having, as a base, CsBr which is a combination of atoms (M ¹ ; Cs, X; Br) in the general formula (1).

The photostimulable phosphor represented by the general formula (1) of the present invention is produced, for example, by the 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, SrCl 2, SrBr 2, SrI 2, BaF 2, BaCI 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.

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 that the pH value C of the obtained aqueous solution is adjusted to 0 <C <7, 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 preferably 500 to 1000 ° C. The firing time varies depending on the filling amount of the raw material mixture, the firing temperature and the like, but is preferably 0.5 to 6 hours.
The firing atmosphere includes a nitrogen gas atmosphere containing a small amount of hydrogen gas, a weak reducing atmosphere such as a carbon dioxide gas atmosphere containing a small amount of carbon monoxide, a neutral atmosphere such as a nitrogen gas atmosphere and an argon gas atmosphere, or a small amount of oxygen gas. A weak oxidizing atmosphere is preferred.

  After firing once under the aforementioned firing conditions, the fired product is taken out from the electric furnace and pulverized, and then the fired product powder is again filled in a heat-resistant container and placed in the electric furnace, and again under the same firing conditions as described above. If the firing is performed, the luminous brightness of the photostimulable phosphor can be further increased, and when the fired product is cooled to the room temperature from the firing temperature, the fired product is taken out of the electric furnace and allowed to cool in the air. Although the desired photostimulable phosphor can be obtained, it may be cooled in the same weakly reducing atmosphere or neutral atmosphere as in the firing.

  In addition, by moving the fired product from the heating part to the cooling part in an electric furnace and quenching in a weakly reducing atmosphere, neutral atmosphere or weakly oxidizing atmosphere, the resulting stimulable phosphor is excited. The emission luminance can be further increased, which is preferable.

The photostimulable phosphor layer of the present invention is formed by a vapor deposition method.
As the vapor phase deposition method of the photostimulable phosphor, an evaporation method, a sputtering method, a CVD method, an ion plating method, and others can be used. In the present invention, the evaporation method is particularly preferable.

Hereinafter, the vapor deposition method suitable for the present invention will be described. Here, since the stimulable phosphor is deposited on the support using the deposition apparatus shown in FIG. 3, it will be described together with the description of the deposition apparatus.
As shown in FIG. 3, the vapor deposition apparatus 1 includes a vacuum vessel 2, an evaporation source 3 that is provided in the vacuum vessel 2 and deposits vapor on the support 11, and a support holder 4 that holds the support 11. A support rotating mechanism 5 for depositing vapor from the evaporation source 3 by rotating the support holder 4 with respect to the evaporation source 3, a vacuum pump 6 for introducing the exhaust in the vacuum vessel 2 and introducing the atmosphere, etc. It has.

Since the evaporation source 3 contains a stimulable phosphor and is heated by a resistance heating method, the evaporation source 3 may be composed of an alumina crucible around which a heater is wound, or a boat or a heater made of a refractory metal. May be. In addition to the resistance heating method, the stimulable phosphor may be heated by an electron beam or a high frequency induction method. However, in the present invention, it is easy to handle with a relatively simple structure and is inexpensive. In addition, the resistance heating method is preferable because it can be applied to a large number of substances. The evaporation source 3 may be a molecular beam source by a molecular source epitaxial method.
The support rotation mechanism 5 includes, for example, a rotation shaft 5a that supports the support holder 4 and rotates the support holder 4, and a motor (not shown) that is disposed outside the vacuum vessel 2 and serves as a drive source for the rotation shaft 5a. Etc.
The support holder 4 is preferably provided with a heater (not shown) for heating the support 11. By heating the support 11, the adsorbate on the surface of the support 11 is separated and removed, and the generation of an impurity layer between the surface of the support 11 and the photostimulable phosphor is prevented, the adhesion is enhanced and the brightness is increased. The film quality of the stimulable phosphor layer can be adjusted.
Furthermore, a shutter (not shown) that blocks a space from the evaporation source 3 to the support 11 may be provided between the support 11 and the evaporation source 3. Substances other than the target substance attached to the surface of the photostimulable phosphor by the shutter can be prevented from evaporating at the initial stage of vapor deposition and adhering to the support 11.

In order to form the photostimulable phosphor layer on the support 11 using the vapor deposition apparatus 1 configured as described above, first, the support 11 is attached to the support holder 4.
Next, the vacuum container 2 is evacuated. Thereafter, the support holder 4 is rotated with respect to the evaporation source 3 by the support rotating mechanism 5, and when the vacuum container 2 reaches a vacuum degree capable of vapor deposition, the stimulable phosphor is evaporated from the heated evaporation source 3. Then, a stimulable phosphor is grown on the surface of the support 11 to a desired thickness. In this case, the distance between the support 11 and the evaporation source 3 is preferably set to 100 mm to 1500 mm.

The stimulable phosphor used as the evaporation source may be processed into a tablet shape by pressure compression or may be in a powder state.
Further, instead of the photostimulable phosphor, a raw material or a raw material mixture may be used.

FIG. 2 is a diagram showing a specific state in which the photostimulable phosphor layer 12 is formed on the support 11 by vapor deposition. The incident angle of the vapor flow 15 of the stimulable phosphor with respect to the normal direction (R) of the surface of the support 11 fixed to the support holder 4 is θ ₂ (60 ° in the figure), and the columnar crystals 13 formed Assuming that the angle with respect to the normal direction (R) of the support surface is θ ₁ (30 ° in the figure), θ ₁ is empirically about half of θ ₂ , and the columnar crystal 13 is formed at this angle. In FIG. 3, the incident angle θ ₂ of the vapor flow 15 is set to 0 °.
Here, the photostimulable phosphor layer 12 containing no binder is formed. However, the gap 14 formed between the columnar crystals 13 may be filled with a filler such as a binder. In addition to reinforcing the phosphor layer 12, a highly light-absorbing substance and a highly reflecting substance may be filled. In addition to providing a reinforcing effect, this is effective in reducing the light diffusion in the lateral direction of the photostimulated excitation light incident on the photostimulable phosphor layer 12.

  In the vapor deposition step, the photostimulable phosphor layer can be formed in a plurality of times. Further, 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.

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 forming the photostimulable phosphor layer by the vapor deposition method, the temperature of the support on which the photostimulable phosphor layer is formed is preferably set to room temperature (rt) to 300 ° C., more preferably 50-200 ° C.

  After forming the photostimulable phosphor layer as described above, the radiation image conversion panel of the present invention is provided by providing a protective layer on the side opposite to the support of the photostimulable phosphor layer as necessary. To manufacture. The protective layer may be formed by directly applying a coating solution for the protective layer to the surface of the photostimulable phosphor layer, or a protective layer separately formed in advance may be adhered to the photostimulable phosphor layer. .

  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, ethylene tetrafluoride-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 preferably 0.1 μm to 2000 μm.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, the embodiment of this invention is not limited to this.
Radiation image conversion panels of Examples 1 to 4, Comparative Example 1, and Comparative Example 2 were produced according to the following method.
[Example 1]
(Production of radiation image conversion panel)
A stimulable phosphor layer was formed by depositing a stimulable phosphor (CsBr: 0.0002Eu) on one side of a support made of a carbon fiber reinforced resin sheet using the deposition apparatus 1 shown in FIG.
That is, first, the phosphor raw material was filled in a resistance heating crucible as an evaporation material, and the support 11 was placed on the rotating support holder 4, and the distance between the support 11 and the evaporation source 3 was adjusted to 400 mm. Subsequently, the inside of the vapor deposition apparatus 1 was once evacuated, Ar gas was introduced and the degree of vacuum was adjusted to 0.1 Pa, and then the temperature of the support 11 was maintained at 100 ° C. while rotating the support 11 at a speed of 10 rpm. . Next, the resistance heating crucible was heated to deposit a stimulable phosphor, and the deposition was terminated when the thickness of the stimulable phosphor layer reached 500 μm.
Next, the stimulable phosphor layer was placed in a protective layer bag in dry air to obtain a radiation image conversion panel having a structure in which the stimulable phosphor layer was sealed.
When the filling factor distribution was measured for the radiation image conversion panel obtained at this time, the filling factor distribution was 8.1% and was an isotropic filling factor distribution. The filling factor distribution was measured by the measurement method described above.

[Example 2]
A radiation image conversion panel was produced in the same manner as in Example 1 except that the distance between the support and the evaporation source was adjusted to 600 mm. At this time, the filling rate distribution of the obtained radiation image conversion panel was 4.4%, which is an isotropic filling rate distribution.

[Example 3]
A radiation image conversion panel was produced in the same manner as in Example 1 except that the distance between the support and the evaporation source was adjusted to 800 mm. At this time, the filling rate distribution of the obtained radiation image conversion panel was 2.9%, which was an isotropic filling rate distribution.

[Example 4]
A radiation image conversion panel was produced in the same manner as in Example 1 except that the distance between the support and the evaporation source was adjusted to 1000 mm. At this time, the filling rate distribution of the obtained radiation image conversion panel was 2.2%, which was an isotropic filling rate distribution.

[Comparative Example 1]
A stimulable phosphor layer was formed by depositing a stimulable phosphor (CsBr: 0.0002Eu) on one side of a support made of a carbon fiber reinforced resin sheet using the deposition apparatus 1A shown in FIG.
That is, first, the resistance heating crucible was filled with the phosphor raw material as an evaporation material, and the support 11 was placed on the support holder 4A, and the distance between the support 11 and the evaporation source 3A was set to 1000 mm.
Subsequently, the inside of the vapor deposition apparatus 1A is once evacuated, Ar gas is introduced and the degree of vacuum is adjusted to 0.1 Pa, and then the support 11 is transported by the support transport mechanism 5A in the horizontal direction with respect to the evaporation source 3A. The temperature of the support 11 was kept at 100 ° C. Next, the resistance heating crucible was heated to deposit a stimulable phosphor, and the deposition was terminated when the thickness of the stimulable phosphor layer reached 500 μm. In FIG. 4, 2A denotes a vacuum container, 6A denotes a slit, 7A denotes a deposition preventing plate, and 8A denotes a vacuum pump.
Next, the stimulable phosphor layer was placed in a protective layer bag in dry air to obtain a radiation image conversion panel having a structure in which the stimulable phosphor layer was sealed.
When the filling factor distribution was measured in the same manner for the radiation image conversion panel obtained at this time, the filling factor distribution was 11.2% and it was an anisotropic filling factor distribution.

[Comparative Example 2]
A radiation image conversion panel was produced in the same manner as in Comparative Example 1 except that the distance between the support and the evaporation source was adjusted to 400 mm. At this time, the filling rate distribution of the obtained radiation image conversion panel was 15.0%, which was an anisotropic filling rate distribution.

And the following evaluation was performed about the radiation image conversion panel obtained as mentioned above.
<Sensitivity unevenness>
The radiation image conversion panel is uniformly irradiated with X-rays having a tube voltage of 80 kVp from the side of the support opposite to the photostimulable phosphor layer, and then the radiation image conversion panel is scanned with He-Ne laser light (633 nm) for excitation. Then, at 25 measurement points arranged at equal intervals on the radiation image conversion panel, the photostimulated luminescence emitted from the photostimulable phosphor layer is received by a light receiver (photomultiplier tube having a spectral sensitivity of S-5). The intensity was measured, and the sensitivity unevenness was evaluated from the variation in intensity between the measurement points. Sensitivity unevenness is obtained by dividing the width of the maximum value and the minimum value at each measurement point of each panel by the average value of the intensities at 25 measurement points, and expressing this in%. Table 1 shows the results.

《Shock resistance》
After dropping a 500 g iron ball from a height position 20 cm away from the radiation image conversion panel, the radiation image conversion panel was visually evaluated. Thereafter, each radiation image conversion panel is irradiated with X-rays having a tube voltage of 80 kVp from the back side of the support, and then the radiation image conversion panel is excited by scanning with a He—Ne laser beam (633 nm) to produce stimulable fluorescence. Stimulated luminescence emitted from the body layer is received by a light receiver (photomultiplier tube with spectral sensitivity S-5) and converted into an electrical signal, which is reproduced as an image by an image reproducing device and printed out from an output device. Then, the obtained printed image was visually evaluated for impact resistance according to the following criteria. Table 1 shows the results.
(Double-circle): There is no crack and it is a uniform image.
○: There is no crack, and the image quality is hardly a concern.
(Triangle | delta): Although a crack is seen and a notch is confirmed, it is a level acceptable practically.
X: Cracks are observed, clear omissions are observed, and practically problematic.

以上、表１の結果から明らかなように、輝尽性蛍光体層の充填率分布が±１０％以下である実施例１〜実施例４は、充填率分布が±１０％を越える比較例１、比較例２に比べて、感度ムラの劣化を防ぐことができ、耐衝撃性に優れる。
また、輝尽性蛍光体層の充填率分布が支持体中心から等方的な実施例１〜実施例４は、充填率分布が異方的な比較例１、比較例２に比べて、高感度及び耐衝撃性に優れていた。
また、蒸着装置についても図４に示すように支持体を水平方向に搬送することによって蒸着する搬送方式に比べて、図３に示すように支持体を回転することによって蒸着する回転方式の方が、支持体上に輝尽性蛍光体層を均一に蒸着させることができ、この点においても本発明の効果に有利であることがわかる。
さらに、実施例４のように充填率分布が小さい程、感度ムラを低減でき、耐衝撃性にも優れることがわかる。

As can be seen from the results in Table 1, Examples 1 to 4 in which the filling rate distribution of the stimulable phosphor layer is ± 10% or less are Comparative Examples 1 in which the filling rate distribution exceeds ± 10%. Compared with Comparative Example 2, it is possible to prevent deterioration of sensitivity unevenness and excellent impact resistance.
Further, Examples 1 to 4 in which the filling rate distribution of the stimulable phosphor layer is isotropic from the center of the support are higher than those in Comparative Examples 1 and 2 in which the filling rate distribution is anisotropic. Excellent sensitivity and impact resistance.
Also, as for the vapor deposition apparatus, the rotation method for vapor deposition by rotating the support body as shown in FIG. 3 is better than the conveyance method for vapor deposition by conveying the support body in the horizontal direction as shown in FIG. It can be seen that the photostimulable phosphor layer can be uniformly deposited on the support, and this point is also advantageous for the effect of the present invention.
Further, it can be seen that as the filling rate distribution is smaller as in Example 4, the sensitivity unevenness can be reduced and the impact resistance is also excellent.

  Therefore, there is a correlation between the filling rate distribution of the photostimulable phosphor layer and the sensitivity and impact resistance. By specifying the filling rate distribution to be ± 10% or less, it is excellent in high sensitivity and impact resistance. Therefore, the image quality of the radiation image can be improved.

It is a schematic sectional drawing which shows an example of the photostimulable phosphor layer formed on the support body. It is a figure which shows a mode that a photostimulable phosphor layer is formed on a support body by a vapor deposition method. It is sectional drawing which shows schematic structure of the vapor deposition apparatus by a rotation system. It is sectional drawing which shows schematic structure of the vapor deposition apparatus by a conveyance system. (a) is a diagram for explaining that the filling rate distribution is isotropic from the center of the support, (b), (c) is that the filling rate distribution is anisotropic from the support center. It is a figure for demonstrating.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Deposition apparatus 2 Vacuum container 3 Evaporation source 5 Support body rotation mechanism 11 Support body 12 Stimulable phosphor layer

Claims (4)

In a radiation image conversion panel comprising a stimulable phosphor layer containing a stimulable phosphor on a support by vapor deposition,
A radiation image conversion panel, wherein the stimulable phosphor layer has a filling rate distribution of ± 10% or less.   The radiation image conversion panel according to claim 1, wherein a filling factor distribution of the photostimulable phosphor layer isotropically changes from a central part of the support to an end part. 3. The radiation image conversion according to claim 1, wherein the photostimulable phosphor layer contains a photostimulable phosphor based on an alkali halide represented by the following general formula (1). panel.
M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : eA (1)
[Wherein, M ¹ is at least one alkali metal atom selected from Li, Na, K, Rb and Cs atoms, and M ² is Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu. And at least one divalent metal atom selected from each atom of Ni, and M ³ is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, At least one trivalent metal atom selected from each atom of Tm, Yb, Lu, Al, Ga and In, and X, X ′ and X ″ are at least selected from each atom of F, Cl, Br and I 1 type of halogen atom, A is Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg. At least one metal atom selected from each atom, and a, b, e each represent a number between 0 ≦ a <0.5,0 ≦ b <0.5,0 <e <1.0.] A vacuum vessel, an evaporation source provided in the vacuum vessel for depositing a stimulable phosphor on a support, and supporting the support and rotating the evaporation source from the evaporation source. The manufacturing method of the radiation image conversion panel which manufactures the radiation image conversion panel as described in any one of Claims 1-3 using the vapor deposition apparatus provided with the support body rotation mechanism which vapor-deposits stimulable fluorescent substance. Because
The stimulable phosphor layer evaporating from the evaporation source is deposited on the support by supporting and rotating the support by the support rotating mechanism to form a stimulable phosphor layer. A method for producing a radiation image conversion panel.

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