JP2002107496A - Panel for converting radiation image, and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image converting panel superior in the adhesive property between a support body and a phosphor layer, and remarkably reduced in cracks in the phosphor layer. SOLUTION: A vapor-deposited film is formed while heating a substrate by a heater, and the output of the heater is thereafter lowered stepwisely to cool the substrate gradually, when the phosphor layer is provided, and this radiation image converting panel is manufactured by forming the vapor-deposited film comprising a phosphor on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a radiation image conversion panel used in a radiation image recording / reproducing method utilizing the stimulable light emission of a stimulable phosphor.

[0002]

2. Description of the Related Art A radiation image recording / reproducing method using a stimulable phosphor is known as an alternative to the conventional radiographic method. This method uses a radiation image conversion panel (a stimulable phosphor sheet) containing a stimulable phosphor, and transmits radiation transmitted through a subject or emitted from a subject to the stimulable phosphor of the panel. The radiation energy stored in the stimulable phosphor is absorbed by the body in a time-series manner by exciting the stimulable phosphor with electromagnetic waves (excitation light) such as visible light and infrared rays. The fluorescent light is emitted as (stimulated emission light), the fluorescence is read photoelectrically to obtain an electric signal, and a radiation image of a subject or a subject is reproduced as a visible image based on the obtained electric signal. After the reading, the panel is prepared for the next photographing after the remaining image is erased.

The radiation image conversion panel used in the radiation image recording / reproducing method has, as a basic structure, a support and a stimulable phosphor layer provided thereon. However, when the stimulable phosphor layer is self-supporting, a support is not necessarily required. In addition, a protective layer is usually provided on the upper surface of the stimulable phosphor layer (the surface opposite to the support side) to protect the phosphor layer from chemical alteration or physical impact.

The stimulable phosphor layer usually comprises a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state. However, the stimulable phosphor layer may be composed of only an aggregate of the stimulable phosphor without a binder formed by a vapor deposition method or a sintering method, or may be formed of a stimulable phosphor. It is also known that a polymer substance is impregnated in the gap of the aggregate. In any of these phosphor layers, the stimulable phosphor has a property of exhibiting stimulable luminescence when irradiated with excitation light after absorbing radiation such as X-rays. Radiation emitted from the specimen is absorbed by the stimulable phosphor layer of the radiation image conversion panel in proportion to the radiation dose, and a radiation image of the subject or the subject is formed on the panel as an accumulated image of radiation energy. . This accumulated image can be emitted as stimulated emission light by irradiating the excitation light, and the accumulated image of radiation energy is imaged by photoelectrically reading the stimulated emission light and converting it into an electric signal. Can be realized.

As another method of the above-mentioned radiation image recording / reproducing method, Japanese Patent Application No. 11-372978 filed by the present applicant discloses a storage phosphor layer containing a stimulable phosphor (and a radiation absorbing phosphor layer). A radiation image forming method using a combination of a radiation image conversion panel having a body layer) and a phosphor screen having a radiation absorbing phosphor layer containing a phosphor that absorbs radiation and emits light in the ultraviolet to visible region, and Radiation imaging materials comprising combinations thereof are described. In this method, radiation transmitted through a subject, diffracted or scattered by the subject, or emitted from the subject is first applied to a fluorescent screen or a radiation absorbing phosphor layer of a radiation image conversion panel in an ultraviolet to visible region. After that, the light is accumulated and recorded as a latent image in the stimulable phosphor layer of the panel. Next, the panel is irradiated with excitation light to photoelectrically read the stimulated emission light from the stimulable phosphor layer to convert it into an image signal, and reconstruct an image corresponding to the spatial energy distribution of radiation from the image signal. Make up. The radiation image conversion panel of the present invention includes an image forming material used in the above method, that is, a panel containing both a stimulable phosphor and a phosphor that absorbs radiation and emits light in the ultraviolet to visible region. , A fluorescent screen is also included.

The radiation image recording / reproducing method (and the radiation image forming method) has many excellent advantages as described above, but the radiation image conversion panel used in this method has as high a sensitivity as possible. It is desired to provide an image with good image quality (sharpness, granularity, etc.).

For the purpose of improving sensitivity and image quality, as described in, for example, Japanese Patent Application Laid-Open No. Sho 62-47600, as a method for manufacturing a radiation image conversion panel, a stimulable phosphor layer is formed by a vapor deposition method. A method of forming by an electron beam evaporation method, which is one of the methods, has been proposed. This method uses a stimulable phosphor or a raw material of a stimulable phosphor as an evaporation source, and irradiates an electron beam with an electron gun to the evaporation source to evaporate the evaporation source.
The phosphor layer is made of a columnar crystal of a stimulable phosphor by being scattered and depositing the evaporated substance on the surface of a substrate such as a metal sheet (forming a vapor deposition film).

[0008] The phosphor layer formed by the vapor deposition method
It does not contain a binder and consists only of a stimulable phosphor. Voids (cracks) exist between the columnar crystals of the stimulable phosphor.
Exists. For this reason, an image with high sensitivity and high sharpness can be obtained. Further, in the vapor deposition method, columnar crystals having a good shape and a well-aligned arrangement can be obtained as compared with other vapor phase deposition methods such as a sputtering method.

Up to now, including the above-mentioned Japanese Patent Application Laid-Open No. 47600/1987, when forming a vapor-deposited film on a substrate by a vapor deposition method, the substrate may be heated in order to obtain a columnar crystal having a good shape. Although it is known, there is no discussion on how to lower the temperature of the heated substrate after forming the deposited film.

[0010]

SUMMARY OF THE INVENTION The present inventor has found that, after heating a substrate such as metal or quartz with a heater, forming a vapor deposition film made of a phosphor on the substrate, and immediately stopping the output of the heater, Because the thermal conductivity of the substrate and the vapor deposition film are quite different and the temperature lowering rate of the substrate is faster, a considerable temperature difference occurs between the two, as a result, the substrate and the vapor deposition film peel off,
When the thickness of the substrate is thin, the substrate warps, or stress distortion remains in the deposited film and cracks are generated inside,
They found that they tended to form uncontrollable voids. This lowers the adhesiveness between the substrate (support) and the phosphor layer, and lowers the quality of the obtained radiation image.

Accordingly, an object of the present invention is to provide a radiation image conversion panel having good adhesion between a substrate (support) and a phosphor layer, and a method of manufacturing the same.

Another object of the present invention is to provide a radiation image storage panel in which cracks in the phosphor layer are significantly reduced, and a method of manufacturing the same. Still another object of the present invention is to provide a radiation image conversion panel that provides a high-sensitivity and high-quality radiation image and a method of manufacturing the same.

[0013]

According to the present invention, there is provided a method for manufacturing a radiation image conversion panel including a step of providing a phosphor layer by forming a vapor deposition film made of a phosphor on a substrate.
A method for manufacturing a radiation image conversion panel, comprising: forming a vapor-deposited film while heating the substrate with a heater; and gradually lowering the output of the heater to gradually cool the substrate.

The present invention also resides in a radiation image conversion panel manufactured by the above method.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the method of the present invention, it is preferable to form a deposited film by an electron beam evaporation method. Preferably, the substrate is cooled at a rate of 1 ° C./min or more and 20 ° C./min or less. The phosphor is preferably a stimulable phosphor, particularly preferably an alkali metal halide-based stimulable phosphor having the following basic composition formula (I).

[0016] ^{M I X · aM II X '} 2 · bM III X "3: zA ‥‥ (I) [ However, M ^I is Li, Na, K, of at least one alkali selected from the group consisting of Rb and Cs Represents a metal; M ^II is Be, Mg, Ca, Sr, Ba, Ni, C
u, represents at least one alkaline earth element or trivalent metal selected from the group consisting of Zn and Cd; M ^III is S
c, Y, La, Ce, Pr, Nd, Pm, Sm, Eu,
Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, A
represents at least one rare earth element or trivalent metal selected from the group consisting of 1, Ga and In; X, X ′ and X ″
Each represents at least one halogen selected from the group consisting of F, Cl, Br and I; A represents Y, Ce,
Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, E
r, Tm, Yb, Lu, Na, Mg, Cu, Ag, Tl
And at least one rare earth element or metal selected from the group consisting of Bi and Bi; and a, b and z are respectively 0 ≦ a <0.5, 0 ≦ b <0.5, and 0 ≦ z <0.2.
Represents a number within the range of

Hereinafter, the method for producing the radiation image storage panel of the present invention will be described in detail by taking as an example a case where a phosphor layer made of a stimulable phosphor is formed. A substrate for forming a vapor-deposited film usually serves also as a support of the radiation image conversion panel, and can be arbitrarily selected from materials known as a support of the conventional radiation image conversion panel. A quartz glass sheet; a metal sheet made of aluminum, iron, tin, chromium and the like; and a resin sheet made of aramid and the like. In a known radiation image conversion panel, in order to improve sensitivity or image quality (sharpness, granularity) as a panel, a light reflecting layer made of a light reflecting material such as titanium dioxide, or a light absorbing material such as carbon black. It is known to provide a light absorbing layer made of The substrate used in the present invention can also be provided with these various layers, and their configuration can be arbitrarily selected according to the desired purpose and application of the radiation image storage panel. Further, JP-A-58-20020
As described in JP-A No. 0, the surface of the substrate on the side of the phosphor layer (the surface of the support on the side of the phosphor layer is coated with an undercoat layer (adhesion-imparting layer) in order to improve the sharpness of the obtained image. ), And when auxiliary layers such as a light reflecting layer or a light absorbing layer are provided, the surface of these auxiliary layers may be formed).

The stimulable phosphor has a wavelength of 400 to 9
Irradiation with excitation light in the range of
A stimulable phosphor that emits stimulable light in the wavelength range of nm is preferred. An example of such a stimulable phosphor is described in JP-B-7-845.
No. 88, JP-A-2-193100 and JP-A-4-3
It is described in detail in each publication of No. 10900.

[0019] Among these, the basic formula ^{(I): M I X ·} aM II X '2 · bM III X "3: zA ‥‥ alkali metal halide stimulable phosphor represented by (I) Is particularly preferred, provided that M ^I is Li, Na, K, Rb
And represents at least one alkali metal selected from the group consisting of Cs, M ^II is Be, Mg, Ca, Sr, B
a, at least one kind of alkaline earth metal or divalent metal selected from the group consisting of Ni, Cu, Zn and Cd, and M ^III is Sc, Y, La, Ce, Pr, Nd, P
m, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
m represents at least one rare earth element or trivalent metal selected from the group consisting of Lu, Al, Ga and In, and A represents Y, Ce, Pr, Nd, Sm, Eu, G
d, Tb, Dy, Ho, Er, Tm, Yb, Lu, N
a, at least one rare earth element or metal selected from the group consisting of Mg, Cu, Ag, Tl and Bi.
X, X ′ and X ″ are F, Cl, Br and I, respectively.
Represents at least one halogen selected from the group consisting of a, b and z are respectively 0 ≦ a <0.5, 0 ≦
b <0.5, 0 ≦ z <0.2.

It is preferable that M ^I in the above basic composition formula (I) contains at least Cs. It is preferable that X contains at least Br. A is particularly preferably Eu or Bi. In addition, the basic composition formula (I) includes, if necessary, aluminum oxide,
A metal oxide such as silicon dioxide or zirconium oxide may be added as an additive in an amount of 0.5 mol or less based on 1 mol of M ^I.

Further, a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor represented by the basic composition formula (II): M ^II FX: zLn ‥‥ (II) is also preferable. However, M ^II is Ba,
Ln represents at least one kind of alkaline earth metal selected from the group consisting of Sr and Ca, and Ln represents Ce, Pr, Sm, E
represents at least one rare earth element selected from the group consisting of u, Tb, Dy, Ho, Nd, Er, Tm and Yb. X represents at least one halogen selected from the group consisting of Cl, Br and I. z is 0 <z ≦ 0.2
Represents a numerical value within the range.

In the above basic composition formula (II), M ^II represents
Ba preferably accounts for more than half. Ln is particularly preferably Eu or Ce. In addition, in the basic composition formula (II), F: X = 1: 1 appears in the notation, which indicates that it has a BaFX type crystal structure, and the stoichiometry of the final composition It does not indicate the composition. In general, a state in which many F ⁺ (X ⁻ ) centers, which are vacancies of X ⁻ ions, are generated in the BaFX crystal is preferable from the viewpoint of increasing the photostimulation efficiency with respect to light of 600 to 700 nm. At this time, F is often slightly more than X.

Although omitted in the basic composition formula (II), one or more of the following additives may be added to the basic composition formula (II) as necessary. bA, wN ^I , xN ^II , yN ^III where A represents a metal oxide such as Al ₂ O ₃ , SiO ₂ and ZrO ₂ . In preventing sintering between M ^II FX particles, it is preferable to use an average particle size of the primary particles has low reactivity with M ^II FX in the following ultrafine particles 0.1 [mu] m. N ^I represents at least one kind of alkali metal compound selected from the group consisting of Li, Na, K, Rb and Cs; N ^II represents an alkaline earth metal compound consisting of Mg and / or Be; ^III is Al, Ga, In,
It represents a compound of at least one trivalent metal selected from the group consisting of Tl, Sc, Y, La, Gd and Lu. As these metal compounds, it is preferable to use halides as described in JP-A-59-75200, but it is not limited thereto.

B, w, x and y are each M ^II
This is the charged addition amount when the number of moles of FX is 1, and 0
≦ b ≦ 0.5, 0 ≦ w ≦ 2, 0 ≦ x ≦ 0.3, 0 ≦ y ≦
Represents a numerical value within each range of 0.3. These figures do not represent the element ratios contained in the final composition for additives that are reduced by baking or subsequent cleaning. Some of the above compounds may remain as added in the final composition.
^Some react with ^II FX or are incorporated.

In addition, if necessary, the basic composition formula (II) may further include, as necessary, a Z compound described in JP-A-55-12145.
n and Cd compounds; TiO ₂ , BeO, MgO, C which are metal oxides described in JP-A-55-160078.
aO, SrO, BaO, ZnO, Y 2 O 3, La 2 O 3, I
n ₂ O ₃ , GeO ₂ , SnO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , Th
O ₂ ; Zr and Sc compounds described in JP-A-56-116777; B compounds described in JP-A-57-23673; As described in JP-A-57-23675.
And Si compounds; tetrafluoroboric acid compounds described in JP-A-59-27980; JP-A-59-4728.
No. 9, hexafluorosilicic acid, hexafluorotitanic acid, and hexafluorozirconic acid, a hexafluoro compound comprising a monovalent or divalent salt of hexafluorozirconic acid; V, Cr, Mn, F
e, a compound of a transition metal such as Co and Ni, or the like may be added. Further, the present invention is not limited to the phosphor containing the above-described additive, and any phosphor having a composition which is basically regarded as a rare earth activated alkaline earth metal fluorinated halide-based stimulable phosphor can be used. It may be.

However, in the present invention, the phosphor is not limited to a stimulable phosphor, and may be a phosphor that absorbs radiation such as X-rays and emits (instantaneously) light in the ultraviolet to visible region. Good. Examples of such phosphors include LnT
aO ₄ : (Nb, Gd) system, Ln ₂ SiO ₅ : Ce system, L
nOX: Tm system (Ln is a rare earth element), CsX system (X is a halogen), Gd ₂ O ₂ S: Tb, Gd ₂ O ₂
S: Pr, Ce, ZnWO ₄ , LuAlO ₃ : Ce, Gd
₃ Ga ₅ O ₁₂ : Cr, Ce, HfO _{2 and the} like.

In the present invention, the phosphor layer can be formed on the support by, for example, an electron beam evaporation method as follows. In the electron beam evaporation method, a columnar crystal having a good shape and a well-aligned array is obtained, and at the same time, the evaporation source is locally heated and evaporated instantaneously. After evaporation (for example, the activator evaporates before the phosphor matrix), the composition of the phosphor charged as the evaporation source does not match the composition of the phosphor in the formed phosphor layer. There is almost nothing.

First, a stimulable phosphor as an evaporation source and a substrate as an object to be deposited are placed in a deposition apparatus, and the inside of the apparatus is evacuated to about 3 × 10 ^{−7 to} 3 × 10 ⁻⁴ Pa. Degree of vacuum. At this time, while maintaining the degree of vacuum at this level, Ar
An inert gas such as a gas or a Ne gas may be introduced. On the other hand, the substrate is heated from the back surface (the side on which the deposited film is not formed) using a suitable heater such as a sheath heater. The substrate temperature varies depending on the evaporation source material, substrate material, etc.
100 to 6 in the case of an alkali halide stimulable phosphor.
Maintain in the range of 00 ° C.

The stimulable phosphor is preferably processed into a tablet (pellet) shape by pressurizing and compression. The compression under pressure is generally performed by applying a pressure in the range of 800 to 1000 kg / cm ² . During compression, the tablet may be heated to a temperature in the range of 50 to 200 ° C., and after compression, the resulting tablet may be subjected to a degassing treatment. Thereby, the relative density of the evaporation source can be increased. If the relative density of the evaporation source is low,
If the phosphor does not evaporate uniformly, the film thickness of the deposited film becomes uneven, bumps adhere to the substrate, and the phosphor itself evaporates unevenly, and the phosphor is activated in the deposited film. Agents and additives may segregate. Further, it is also possible to use the raw material or the raw material mixture instead of the stimulable phosphor.

Next, an electron beam is generated from the electron gun and irradiated to the evaporation source. At this time, the electron beam acceleration voltage is set to 1.5
It is desirable to set the voltage to not less than kV and not more than 5.0 kV. If the acceleration voltage is lower than 1.5 kV, the voltage becomes unstable, the beam position of the electron beam fluctuates, or the shape of the scanning surface by the electron beam of the evaporation source changes to keep the evaporation surface flat. It becomes difficult. On the other hand, when the acceleration voltage is higher than 5.0 kV, the columnar crystals of the phosphor that grows in vapor phase by evaporation become uneven.

The irradiation of the electron beam causes the stimulable phosphor of the evaporation source to be heated, evaporated, scattered, and deposited on the substrate surface. The deposition rate of the phosphor, that is, the deposition rate is generally 0.1 to
1000 μm / min, preferably 1 to 100
in the range of μm / min.

After the electron beam irradiation, with the degree of vacuum maintained, the output of the heater is reduced stepwise to gradually cool the substrate and the deposited film thereon. The cooling rate of the substrate varies depending on the substrate material and the like, but is preferably from 1 ° C./min to 20 ° C./min, particularly preferably from 1 ° C./min to 10 ° C./min. If the cooling rate is lower than 1 ° C./min, the workability in a series of manufacturing steps deteriorates. On the other hand, when the cooling rate is higher than 20 ° C./min, cracks tend to occur in the phosphor layer. After cooling the substrate to a certain temperature, the inside of the apparatus is returned to the atmospheric pressure, and the substrate is taken out of the apparatus.

The irradiation of the electron beam may be performed a plurality of times to form two or more phosphor layers, or different phosphors may be co-evaporated using a plurality of electron guns. Good. Further, it is also possible to synthesize a phosphor on a substrate using the phosphor raw material and simultaneously form the phosphor layer. further,
After the vapor deposition, the phosphor layer may be subjected to a heat treatment (annealing treatment). Further, the vapor deposition method used in the present invention is not limited to the above-described electron gland vapor deposition method, and other vapor deposition methods such as a resistance heating method can be used.

In this way, a phosphor layer in which the columnar crystals of the stimulable phosphor have grown substantially in the thickness direction is obtained. The phosphor layer does not contain a binder and consists only of a stimulable phosphor,
Voids (cracks) exist between the columnar crystals of the stimulable phosphor. The thickness of the phosphor layer is usually 50 to 1
000 μm, preferably 200 μm to 70 μm.
It is in the range of 0 mm.

The substrate does not necessarily need to also serve as a support for the radiation image conversion panel. After the formation of the vapor deposition film, the vapor deposition film is peeled off from the substrate and bonded to a separately prepared support using an adhesive or the like. Then, a method of providing a phosphor layer may be used.

It is desirable to provide a protective layer on the surface of the phosphor layer for the convenience of transportation and handling of the radiation image storage panel and to avoid a change in characteristics. The protective layer is desirably transparent so that it hardly affects the incidence of excitation light and the emission of stimulated emission light, and the radiation image conversion panel is sufficiently protected from external physical and chemical impacts. It is desirable that it is chemically stable, has high moisture resistance, and has high physical strength so that it can be protected.

As the protective layer, a solution prepared by dissolving a transparent organic polymer substance such as a cellulose derivative, polymethyl methacrylate, or an organic solvent-soluble fluororesin in an appropriate solvent is used for the stimulable phosphor layer. An organic polymer film such as polyethylene terephthalate or a sheet for forming a protective layer such as a transparent glass plate is separately formed on the surface of the phosphor layer using an appropriate adhesive. Those provided or those obtained by depositing an inorganic compound on a phosphor layer by vapor deposition or the like are used. In addition, magnesium oxide, zinc oxide,
Various additives such as light scattering fine particles such as titanium dioxide and alumina, slip agents such as perfluoroolefin resin powder and silicone resin powder, and cross-linking agents such as polyisocyanate may be dispersedly contained. The thickness of the protective layer is generally in the range of about 0.1 to 20 μm when the protective layer is made of a high-molecular substance, and 1 μm when the protective layer is made of an inorganic compound such as glass.
It is in the range of 00 to 1000 μm.

A fluororesin coating layer may be provided on the surface of the protective layer in order to enhance the contamination resistance of the protective layer. The fluororesin coating layer can be formed by applying a fluororesin solution prepared by dissolving (or dispersing) a fluororesin in an organic solvent on the surface of the protective layer and drying. The fluororesin may be used alone, but is usually used as a mixture of the fluororesin and a resin having a high film forming property. Also,
An oligomer having a polysiloxane skeleton or an oligomer having a perfluoroalkyl group can be used in combination. The fluororesin coating layer may be filled with a particulate filler in order to reduce interference unevenness and further improve the quality of a radiographic image. The thickness of the fluororesin coating layer is usually in the range of 0.5 to 20 μm. In forming the fluororesin coating layer, additional components such as a cross-linking agent, a hardening agent, an anti-yellowing agent and the like can be used in combination. In particular, the addition of a crosslinking agent is advantageous for improving the durability of the fluororesin coating layer.

Although the radiation image conversion panel of the present invention is obtained as described above, the configuration of the panel of the present invention may include various known variations. For example, for the purpose of improving the sharpness of the obtained image, at least one of the above-mentioned layers may be colored with a coloring agent that absorbs excitation light but does not absorb stimulating light (Japanese Patent Publication No. No. 59-23400).

[0040]

EXAMPLES Example 1 (1) Preparation of evaporation source 100 g of cesium bromide (CsBr, 0.47 mol) and 1.8404 g of europium bromide (EuBr ₃ , 4.7 ×)
10 ⁻³ mol) in a mortar, and then mixed by stirring with a stirring vibrator for 15 minutes. The resulting mixture was placed in a furnace, evacuated for 3 minutes, and then heated to 525 ° C. in a nitrogen atmosphere.
For 2 hours. After firing, the furnace was evacuated for 15 minutes to cool the fired product. Then, the obtained europium-activated cesium bromide (CsBr: 0.01 Eu) stimulable phosphor was pulverized in a mortar, and then press-compressed at a pressure of 800 kg / cm ² to prepare a tablet for vapor deposition. Tablets with an additional temperature of 15
Evacuation was performed at 0 ° C. for 2 hours to perform a degassing treatment.

(2) Formation of Phosphor Layer An aluminum substrate (support) was placed in a vapor deposition apparatus. After placing the above evaporation source at a predetermined position in the apparatus, the inside of the apparatus is evacuated with a diffusion pump to 4.0 × 10 ^−9.
The degree of vacuum was set to kg / cm ² . On the other hand, the substrate was heated from the back surface by heat radiation using a sheath heater to set the temperature of the back surface of the substrate to 300 ° C. At this time, the temperature of the sheathed heater was 400 ° C. (hereinafter, the temperature and the temperature change are the temperature and the temperature change in the sheathed heater). Then
The deposition source was irradiated with an electron beam having an accelerating voltage of 4.0 kV and 60 W from an electron gun to deposit a stimulable phosphor on the substrate at a rate of 25 μm / min. After that, the irradiation of the electron beam was stopped, and the output of the heater was gradually reduced while maintaining the above-mentioned degree of vacuum to cool the substrate at a cooling rate of 1 ° C./min. When the heater temperature reached 250 ° C., air was introduced into the apparatus to return to atmospheric pressure, and the substrate was taken out of the apparatus. On the substrate, a deposited film (thickness: 250 μm) having a structure in which columnar crystals of a phosphor having a width of about 10 μm and a length of about 250 μm were densely arranged almost vertically in a vertical direction. Separately, a deposition film was formed in the same manner as described above using a quartz substrate (support). Thus, two types of radiation image conversion panels each comprising a support and a stimulable phosphor layer were produced.

[Example 2] In the same manner as in Example 1, except that the substrate was cooled at a cooling rate of 10 ° C / min by changing the output of the heater after irradiating the electron beam, the present invention was carried out. A radiation image conversion panel was manufactured.

Example 3 The procedure of Example 1 was repeated, except that the substrate was cooled at a cooling rate of 20 ° C./min by changing the output of the heater after the irradiation with the electron beam. A radiation image conversion panel was manufactured.

Comparative Example 1 A comparative radiation image conversion panel was manufactured in the same manner as in Example 1 except that the output of the heater was stopped immediately after the electron beam irradiation and the substrate was allowed to cool. .

[Evaluation of Performance of Radiation Image Conversion Panel] The adhesiveness of each radiation image conversion panel and the state of the stimulable phosphor layer were evaluated.

(1) Adhesion Whether peeling occurred between the support (substrate) and the stimulable phosphor layer was visually observed and evaluated according to the following criteria. A: No peeling occurred. B: Peeling occurred slightly, but was at a level that caused no practical problem. C: Peeling occurred in some cases. D: Peeling occurred.

(2) State of stimulable phosphor layer The stimulable phosphor layer is cut in the depth direction, and it is observed by an electron microscope whether or not there is a crack in the cross section, and evaluated according to the following criteria. did. A: There was no crack. B: Although there were some cracks, they were of no problem in practical use. C: There was a crack. D: There were many cracks. Table 1 summarizes the obtained results.

[0048]

[Table 1] Table 1 Adhesion of aluminum substrate and quartz substrate Adhesion of phosphor layer Phosphor layer ────────────────────────────────── Example 1 A A A A Example 2 A B A A Example 3 B B A B ────────────────────────────────── Comparative Example 1 D D C C ──────────────────────────────────

As is evident from the results in Table 1, the radiation image conversion panel manufactured according to the method of the present invention by gradually lowering the output of the heater and cooling the substrate (Example 1)
In Nos. To 3), no peeling occurred between the substrate and the stimulable phosphor layer, and the adhesion was good, regardless of whether the substrate material was aluminum or quartz. Also, almost no cracks were formed in the stimulable phosphor layer.

On the other hand, the radiation image conversion panel (Comparative Example 1) manufactured by immediately stopping the output of the heater and cooling the substrate in accordance with the conventional method, no matter which substrate material is used, the radiation image conversion panel and the photostimulable Peeling occurs with the phosphor layer,
Cracks also occurred in the stimulable phosphor layer. Particularly, in the case of an aluminum substrate, both peeling and cracking were remarkable.

[0051]

According to the present invention, after the vapor deposition film is formed, the output of the heater is gradually reduced to gradually cool the substrate, thereby preventing the vapor deposition film from peeling off from the substrate. The generation of cracks inside can be significantly prevented. Therefore, the radiation image conversion panel manufactured according to the method of the present invention can provide a radiation image with high sensitivity and excellent image quality such as sharpness and granularity.

Front page of the continued F-term (reference) 2G083 AA03 BB01 CC02 CC04 DD14 EE07 4H001 CA04 CA08 XA00 XA03 XA04 XA09 XA11 XA12 XA13 XA17 XA19 XA20 XA21 XA28 XA29 XA30 XA31 XA35 XA37 XA38 XA39 XA48 XA49 XA53 XA55 XA56 YA11 YA12 YA29 YA39 YA47 YA58 YA59 YA60 YA62 YA63 YA64 YA65 YA66 YA67 YA68 YA69 YA70 YA81 YA83

Claims (6)

[Claims] In a method of manufacturing a radiation image conversion panel, the method includes a step of providing a phosphor layer by forming a vapor deposition film made of a phosphor on a substrate, wherein the vapor deposition film is formed while heating the substrate with a heater. Thereafter, the output of the heater is reduced stepwise to gradually cool the substrate, and the method for manufacturing a radiation image conversion panel is characterized. 2. The method for manufacturing a radiation image conversion panel according to claim 1, wherein a vapor deposition film is formed by an electron beam vapor deposition method. 3. The method of manufacturing a radiation image conversion panel according to claim 1, wherein the substrate is cooled at a rate of 1 ° C./min to 20 ° C./min. 4. The method according to claim 1, wherein the phosphor is a stimulable phosphor. 5. The stimulable phosphor, basic composition formula ^{(I): M I X ·} aM II X '2 · bM III X "3: zA ‥‥ (I) [ However, M ^I is Li, Na , K, represents at least one alkali metal selected from the group consisting of Rb and Cs; M ^II is be, Mg, Ca, Sr, Ba, Ni, C
u, represents at least one alkaline earth element or trivalent metal selected from the group consisting of Zn and Cd; M ^III is S
c, Y, La, Ce, Pr, Nd, Pm, Sm, Eu,
Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, A
represents at least one rare earth element or trivalent metal selected from the group consisting of 1, Ga and In; X, X ′ and X ″
Each represents at least one halogen selected from the group consisting of F, Cl, Br and I; A represents Y, Ce,
Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, E
r, Tm, Yb, Lu, Na, Mg, Cu, Ag, Tl
And at least one rare earth element or metal selected from the group consisting of Bi and Bi; and a, b and z are respectively 0 ≦ a <0.5, 0 ≦ b <0.5, and 0 ≦ z <0.2.
The method for producing a radiation image storage panel according to claim 4, wherein the alkali metal halide-based phosphor has the following formula: 6. A radiation image conversion panel manufactured by the method according to claim 1. Description: