JP2002350597A - Radiation image conversion panel and method for manufacturing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image conversion panel that exhibits high sharpness and a method for manufacturing the radiation image conversion panel. SOLUTION: The radiation image conversion panel which has a stimulable phosphor layer 12 on a support 11 is characterized in that the stimulable phosphor layer 12 is formed by a vapor growth method (or a vapor deposition method) so as to have the film thickness of 50 μm or more and the transmissivity or reflectance of the stimulable phosphor layer is 20% or higher when the light whose wavelength is 680 nm is incident on the layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a so-called radiographic method using a silver salt to obtain a radiographic image has been used. However, a method of imaging a radiographic image without using a silver salt has been developed. That is, the radiation transmitted through the subject is absorbed by the fluorescent material, and then the fluorescent material is excited with a certain energy to emit the radiation energy stored in the fluorescent material as fluorescent light, and the fluorescent light is detected. A method for imaging is disclosed.

As a specific method, a radiation image conversion method using a panel provided with a stimulable phosphor layer on a support and using one or both of visible light and infrared light as excitation energy has been known ( U.S. Pat. No. 3,859,
No. 527).

Using a stimulable phosphor of higher luminance and higher sensitivity
For example, Japanese Patent Laid-Open No. 59-75
BaFX: Eu described in No. 200, etc.²⁺System (X:
Cl, Br, I) a radiation image conversion method using a phosphor,
Arca as described in JP-A-61-72087 and the like
Radiation image conversion method using rehalide phosphor, 61
No.-73786, 61-737787, etc.
And Tl as a co-activator ⁺And Ce³⁺, Sm³⁺, Eu
³⁺, Y³⁺, Ag⁺, Mg²⁺, Pb²⁺, In³⁺Metal
Alkali halide phosphors have been developed.

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

As one of these attempts, a fine stimulable phosphor formed by depositing a stimulable phosphor on a support having a fine concavo-convex pattern as disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 61-142497. There is a method using a stimulable phosphor layer composed of pseudo columnar blocks.

Further, as described in JP-A-61-142500, cracks between columnar blocks obtained by depositing a stimulable phosphor on a support having a fine pattern are subjected to a shock treatment, and A method using a radiation image conversion panel having a developed stimulable phosphor layer.
No. 3,973,737, a method using a radiating phosphor conversion panel in which a stimulable phosphor layer formed on the surface of a support is cracked from its surface side to form a pseudo columnar shape. As described in JP-A-62-110200, a method of forming a stimulable phosphor layer having a cavity on the upper surface of a support by vapor deposition, and then growing the cavity by heat treatment to form a crack has been proposed. I have.

Further, Japanese Patent Application Laid-Open No. 2-588000 discloses a stimulable 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.

In any of these attempts to control the shape of the stimulable phosphor layer, the stimulable phosphor layer is formed in a columnar shape so that stimulable excitation light (or stimulable luminescence) is generated in the lateral direction. Diffusion can be suppressed (it reaches the surface of the support while repeating reflection at the crack (columnar crystal) interface), so that sharpness of an image due to stimulated emission can be significantly increased.

However, these vapor phase growths (deposition)
However, even in a radiation image conversion panel having a stimulable phosphor layer formed by the method described above, the sharpness required from the market is not sufficiently improved, and further improvement has been demanded.

In particular, recently, high-power semiconductor lasers having a wavelength around 680 nm as the excitation wavelength of the stimulable phosphor are often used in the market because the device unit can be small (compactness). In the radiation image conversion panel to which the technique of (1) is applied, the transmittance at the wavelength is low, and therefore, the excitation light is easily scattered in the stimulable phosphor layer. Was.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a radiation image conversion panel exhibiting high sharpness and a method for manufacturing the radiation image conversion panel.

[0013]

The above objects of the present invention have been attained by the following items 1 to 10.

1. In a radiation image conversion panel having a stimulable phosphor layer on a support, at least one stimulable phosphor layer contains a stimulable phosphor represented by the above general formula (1), The stimulable phosphor layer is formed so as to have a thickness of 50 μm or more by a vapor deposition method (also referred to as a vapor deposition method), and light having a wavelength of 680 nm is incident as excitation light of the stimulable phosphor. A radiation image conversion panel, wherein the stimulable phosphor layer has a transmittance or a reflectance of 20% or more when the stimulable phosphor layer is formed.

2. M ¹ in the general formula (1) is K, Rb
2. The radiation image conversion panel according to the above item 1, wherein the radiation image conversion panel is at least one alkali metal selected from the group consisting of Cs and Cs.

3. 3. The radiation image conversion panel according to the above item 1 or 2, wherein X in the general formula (1) is at least one halogen selected from Br and I.

4. M ² in the general formula (1) is Be, M
4. The radiation image conversion panel according to any one of the above items 1 to 3, wherein the radiation image conversion panel is at least one kind of divalent metal selected from g, Ca, Sr, and Ba.

5. M ³ in the general formula (1) is Y or C
e, Sm, Eu, Al, La, Gd, Lu, Ga, and at least one trivalent metal selected from the group consisting of In and the radiation image according to any one of the above items 1 to 4, Conversion panel.

6. B in the general formula (1) is 0 ≦ b ≦ 1
The radiation image conversion panel according to any one of the 1 to 5, characterized in that it is a 0 ^-2.

[7] FIG. A in the general formula (1) is Eu, C
The radiation image conversion panel according to any one of 1 to 6, wherein the radiation image conversion panel is at least one metal selected from the group consisting of s, Sm, Tl, and Na.

8. 8. The radiation image conversion panel according to any one of 1 to 7, wherein the stimulable phosphor has a columnar crystal.

9. 9. The radiation image conversion panel according to the item 8, wherein the columnar crystal has a stimulable phosphor represented by the general formula (2) as a main component.

10. 10. A method for manufacturing a radiation image conversion panel, wherein the stimulable phosphor layer is formed by a vapor phase growth method when producing the radiation image conversion panel according to any one of the above items 1 to 9.

Hereinafter, the present invention will be described in detail. The present inventors have conducted various studies to achieve the above-described object, and as a result, in a radiation image conversion panel having a stimulable phosphor layer on a support, at least one stimulable phosphor layer is It contains a stimulable phosphor represented by the general formula (1), is formed so that the stimulable phosphor layer has a thickness of 200 μm or more by a vapor phase growth method, and emits light having a wavelength of 680 nm. By adjusting the transmittance or reflectance of the stimulable phosphor layer to 20% or more when incident, a radiation image conversion panel showing an image with extremely high sharpness can be obtained. .

The stimulable phosphor represented by the general formula (1) according to the present invention will be described. The stimulable phosphor of the phosphor represented by the general formula according to the present invention (1), M ^I is, Na, K, represents at least one alkali metal selected from Rb and Cs, Rb And Cs
Alkaline earth metals selected from are preferred, and Cs is more preferably used.

M ² is Be, Mg, Ca, Sr, Ba, Z
A divalent metal selected from the group consisting of n, Cd, Cu, and Ni, of which Be,
It is a divalent metal selected from the group consisting of Mg, Ca, Sr and Ba.

M ³ is Sc, Y, La, Ce, Pr, N
d, Pm, Sm, Eu, Gd, Tb, Dy, Ho, E
represents a trivalent metal selected from the group consisting of r, Tm, Yb, Lu, Al, Ga and In, and among them, Y, Ce, Sm, Eu, Al, La, G
It is a trivalent metal selected from the group consisting of d, Lu, Ga and In.

X, X 'and X "are at least one halogen selected from the group consisting of F, Cl, Br and I from the viewpoint of improving the stimulable light emission luminance of the stimulable phosphor. And at least one halogen selected from Br and more preferably used is Br.
And I is a halogen selected from the group consisting of

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

The stimulable phosphor represented by the general formula (1) according to the present invention is produced, for example, by the following production method.

First, (a) NaF, N
aCl, NaBr, NaI, KF, KCl, KBr, K
I, RbF, RbCl, RbBr, RbI, CsF, C
one or more of sCl, CsBr and 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 , BaC
l ₂ , BaBr ₂ , BaBr ₂ .2H ₂ O, BaI ₂ , Zn
F ₂ , ZnCl ₂ , ZnBr ₂ , ZnI ₂ , CdF ₂ , Cd
Cl ₂ , CdBr ₂ , CdI ₂ , CuF ₂ , CuCl ₂ , C
uBr ₂ , CuI, NiF ₂ , NiCl ₂ , NiBr ₂ , N
one or more of iI ₂ , and (c) in general formula (1), Eu, Tb, In, Cs, Ce, T
m, Dy, Pr, Ho, Nd, Yb, Er, Gd, L
An activator raw material having a metal selected from the group consisting of u, Sm, Y, Tl, Na, Ag, Cu and Mg is used.

In the stimulable phosphor represented by the stoichiometric formula (I), 0 ≦ a <0.5, preferably 0 ≦ a <0.01, 0 ≦ b <0.5, preferably 0 .Ltoreq.b.ltoreq.10.sup.- ² 0 <e.ltoreq.0.2, preferably 0 <e.ltoreq.1.
The phosphor material of (c) is weighed and sufficiently mixed using a mortar, a ball mill, a mixer mill or the like.

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 from 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, an argon gas atmosphere, or a small amount of an oxygen gas. A weakly oxidizing atmosphere is preferred. After firing once under the above firing conditions,
The fired product is taken out of the electric furnace and pulverized. Thereafter, the fired product powder is again filled in a heat-resistant container and put in an electric furnace, and re-firing is performed under the same firing conditions as described above to further increase the emission luminance of the phosphor. Also, when the fired product is cooled to a room temperature from the firing temperature, the desired phosphor can be obtained by removing the fired product from the electric furnace and allowing it to cool in air, but the same as in firing. Alternatively, cooling may be performed in a weak reducing atmosphere or a neutral atmosphere. In addition, the fired product is moved from the heating unit to the cooling unit in the electric furnace, and is rapidly cooled in a weak reducing atmosphere, a neutral atmosphere, or a weak oxidizing atmosphere, so that the emission luminance due to the photostimulation of the obtained phosphor is reduced. It can be even higher.

The stimulable phosphor layer according to the present invention is formed by a vapor deposition method (also referred to as a vapor deposition method).

As the vapor phase growth method of the stimulable phosphor, a vapor deposition method, a sputtering method, an ion plating method, and others can be used.

In the vapor deposition method as the first method, first, a support is placed in a vapor deposition apparatus, and then the inside of the apparatus is evacuated to a vacuum degree of about 1.333 × 10 ⁻⁴ Pa. Then
At least one of the stimulable phosphors is heated and evaporated by a method such as a resistance heating method or an electron beam method to grow the stimulable phosphor to a desired thickness on the surface of the support.

As a result, a stimulable phosphor layer containing no binder is formed, but it is also possible to form the stimulable phosphor layer in a plurality of times in the vapor deposition step. Further, in the vapor deposition step, it is possible to form a stimulable phosphor layer at the same time as synthesizing a desired stimulable phosphor on a support by performing co-evaporation using a plurality of resistance heaters or electron beams. is there.

After the deposition is completed, a radiation image conversion panel of the present invention is manufactured by providing a protective layer on the side of the stimulable phosphor layer opposite to the support side, if necessary. After the stimulable phosphor layer is formed on the protective layer, a procedure for providing a support may be adopted.

Further, in the above-mentioned vapor deposition method, at the time of vapor deposition, the object to be deposited (support or protective layer) may be cooled or heated as required. After the deposition, the stimulable phosphor layer may be subjected to a heat treatment. In the above-described 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, the support is placed in a sputtering apparatus as in the case of the vapor deposition method, and then the inside of the apparatus is once evacuated to 1.333 × 10 ^-4.
The degree of vacuum is set to about Pa, and then an inert gas such as Ar or Ne is introduced into the sputtering apparatus as a gas for sputtering to a gas pressure of about 1.333 × 10 ^-1 Pa. Next, a stimulable phosphor layer is grown to a desired thickness on the surface of the support by sputtering using the stimulable phosphor as a target.

In the sputtering step, various applied processes can be used as in the vapor deposition method.

As a third method, there is a CVD method. Also,
A fourth method is an ion plating method.

The growth rate of the stimulable phosphor layer in the vapor phase growth is preferably 0.05 μm / min to 300 μm / min. If 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, which is not preferable. When the radiation image conversion panel is obtained by the above-described vacuum deposition method, sputtering method, or the like, since the binder is not present, the packing density of the stimulable phosphor can be increased, and the radiation is preferable in terms of sensitivity and resolution. An image conversion panel is obtained.

The dry thickness of the stimulable phosphor layer varies depending on the purpose of use of the radiation image conversion panel and the type of the stimulable phosphor, but is preferably 50 μm or more from the viewpoint of obtaining the effects described in the present invention. A film thickness is required, and preferably,
50 μm to 300 μm, more preferably 100 μm
μm to 300 μm, particularly preferably 150 μm
３００300 μm.

In producing the stimulable phosphor layer by the vapor phase growth method, the temperature of the support on which the stimulable phosphor layer is formed is preferably set to 100 ° C. or higher, more preferably 150 ° C. or higher, particularly preferably 150 ° C.
C. to 400C.

Further, from the viewpoint of obtaining a radiation image conversion panel exhibiting high sharpness, the transmittance or reflectance of the stimulable phosphor layer according to the present invention needs to be 20% or more, but is preferably. , 30% or more, and more preferably,
40% or more.

In the present invention, when the support is a transparent support such as a glass substrate or the like, the transmittance of the stimulable phosphor layer is measured, and a mirror surface such as aluminum reflecting the light on the substrate is used. When processing (for example, vapor deposition etc.) is performed,
The reflectance of the stimulable phosphor layer is measured.

Here, the measurement of the transmittance or the reflectance can be performed using the following measuring apparatus under the same measuring conditions.

Apparatus: HITACHI557 type, Spec
trophotometer Measurement conditions Wavelength of measurement light: 680 nm Scan speed: 120 nm / min Number of repetitions: 10 Responses: set to Auto The stimulable phosphor layer according to the radiation image conversion panel of the present invention is formed on a support by the general formula ( The stimulable phosphor represented by 1) or the general formula (2) is formed by vapor-phase growth, and it is preferable that the stimulable phosphor forms a columnar crystal during layer formation.

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

Next, the formation of the stimulable phosphor layer according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view showing an example of a stimulable phosphor layer having columnar crystals formed on a support by using the above-described vapor deposition method. 11
Denotes a support, 12 denotes a stimulable phosphor layer, and 13 denotes a columnar crystal constituting the stimulable phosphor layer. Reference numeral 14 denotes a gap formed between the columnar crystals.

FIG. 2 is a view showing a state in which a stimulable phosphor layer is formed on a support by vapor deposition. The stimulable phosphor vapor flow 16 is directed to the normal direction (R) of the support surface. Assuming that the incident angle is θ ₂ (incident at 60 ° in the figure), the angle of the formed columnar crystal with respect to the normal direction (R) of the support surface is θ ₁ (about 30 ° in the figure, empirically At this angle, columnar crystals are formed.

Since the stimulable phosphor layer formed on the support in this manner does not contain a binder, the stimulable phosphor layer has excellent directivity, and the directivity of stimulable excitation light and stimulable luminescence is low. The thickness is higher than that of a radiation image conversion panel having a dispersion type stimulable phosphor layer in which a stimulable phosphor is dispersed in a binder. Further, the sharpness of the image is improved by reducing the scattering of the stimulating light in the stimulable phosphor layer.

The gap between the columnar crystals may be filled with a filler such as a binder to reinforce the stimulable phosphor layer and to fill a material having a high light absorption, a material having a high light reflectance, or the like. May be
This is effective not only in providing the reinforcing effect, but also in reducing the lateral light diffusion of the stimulating excitation light incident on the stimulable phosphor layer.

The substance having a high reflectivity is defined as stimulating excitation light (500
To 900 nm, especially 600 to 800 nm). For example, a white pigment and a coloring material in a green to red region such as aluminum, magnesium, silver, indium and other metals can be used.

The white pigment can also reflect stimulated emission.
You. As a white pigment, TiO_Two(Anatase type, rutile
Type), MgO, PbCO_Three・ Pb (OH)_Two, BaS
O_Four, Al_TwoO_Three, M (II) FX (where M (II) is B
a is at least one of a, Sr and Ca, and X is C
1 and at least one of Br. ), Ca
CO _Three, ZnO, Sb_TwoO_Three, SiO_Two, ZrO_Two, Litopo
(BaSO_Four・ ZnS), magnesium silicate, basic
Examples include silicate sulfate, basic lead phosphate, and aluminum silicate.
Can be These white pigments have strong hiding power and high refractive index.
Irritating by reflecting or refracting light
The luminescence is easily scattered and the feeling of the radiation image conversion panel obtained
The degree can be significantly improved.

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

The coloring material may be an organic or inorganic coloring material. Examples of organic color materials include Pomelo Fast Blue 3G (manufactured by Hoechst), Estrol Brill Blue N-3RL (manufactured by Sumitomo Chemical), and D & C Blue No. 1
(Made by National Aniline), Spirit Blue (made by Hodogaya Chemical), Oil Blue No. 603 (manufactured by Orient), Kiton Blue A (manufactured by Ciba Geigy), Aizen Chillon Blue GLH (manufactured by Hodogaya Chemical), Lake Blue AFH (manufactured by Kyowa Sangyo), 6MX Primocyanin (manufactured by Inabata Sangyo), Brill Acid Green 6BH (manufactured by Hodogaya) Chemical Blue), Cyan Blue BNRCS (manufactured by Toyo Ink), Lionoyl Blue SL (manufactured by Toyo Ink) and the like are used.
Also, the color index No. 24411, 23160,
74180, 74200, 22800, 23154, 2
3155, 24401, 14830, 15050, 15
760, 15707, 17941, 74220, 134
25, 13361, 13420, 11836, 7414
And organic metal complex salt coloring materials such as 0, 74380, 74350, and 74460. Ultramarine, cobalt blue, cerulean blue, chromium oxide, TiO
Examples include _2- ZnO-Co-NiO-based pigments.

As the support used in the radiation image storage panel of the present invention, various types of glass, polymer materials, metals and the like are used. For example, plate glass such as quartz, borosilicate glass, chemically strengthened glass, cellulose, etc. A plastic film such as an acetate film, a polyester film, a polyethylene terephthalate film, a polyamide film, a polyimide film, a triacetate film, a polycarbonate film, a metal sheet such as an aluminum sheet, an iron sheet, a copper sheet or a metal sheet having a coating layer of the metal oxide. Is preferred. The surface of the support may be a smooth surface or a mat surface for the purpose of improving the adhesion to the stimulable phosphor layer.

In the present invention, an adhesive layer may be provided on the surface of the support, if necessary, in order to improve the adhesion between the support and the stimulable phosphor layer. The thickness of the support varies depending on the material of the support to be used and the like, but is generally 80 μm to 2000 μm, and from the viewpoint of handling, more preferably 80 μm to 1000 μm.

The stimulable phosphor layer according to the present invention may have a protective layer. The protective layer may be formed by directly applying a coating liquid for a protective layer on the stimulable phosphor layer, or may be formed by adhering a separately formed protective layer on the stimulable phosphor layer. Alternatively, a procedure of forming a stimulable phosphor layer on a separately formed protective layer may be taken. As the material of the protective layer, cellulose acetate, nitrocellulose, polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene terephthalate, polyethylene, polyvinylidene chloride, nylon, polytetrafluoroethylene, polytrifluoride-
Conventional protective layer materials such as ethylene chloride, ethylene tetrafluoride-propylene hexafluoride copolymer, vinylidene chloride-vinyl chloride copolymer, and vinylidene chloride-acrylonitrile copolymer are used. Alternatively, a transparent glass substrate can be used as the protective layer. Further, this protective layer is made of SiC, SiO ₂ , S
An inorganic material such as iN or Al ₂ O ₃ may be stacked. The thickness of these protective layers is generally 0.1 μm to 2 μm.
It is preferably about 000 μm.

FIG. 3 is a schematic diagram showing an example of the configuration of the radiation image conversion panel of the present invention. In FIG. 3, reference numeral 21 denotes a radiation generator, 22 denotes a subject, 23 denotes a radiation image conversion panel having a visible light or infrared light stimulable phosphor layer containing a stimulable phosphor, and 24 denotes radiation of the radiation image conversion panel 23. A stimulating excitation light source for emitting a latent image as stimulating light, 25 is a photoelectric conversion device for detecting the stimulating light emitted from the radiation image conversion panel 23, and 26 is a photoelectric conversion signal detected by the photoelectric converting device 25. Is a device for reproducing the image, 27 is a device for displaying the reproduced image, 28 is a device for cutting the reflected light from the light source 24 and
3 is a filter for transmitting only the light emitted from 3. FIG. 3 shows an example in which a radiation transmission image of a subject is obtained. However, when the subject 12 itself emits radiation, the radiation generator 21 is not particularly necessary. In addition, the photoelectric conversion device 25 and the subsequent devices are not limited to those described above as long as the optical information from the radiation image conversion panel 23 can be reproduced as an image in some form.

As shown in FIG. 3, when the subject 22 is disposed between the radiation generator 21 and the radiation image conversion panel 23 and is 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. And its 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 the stimulable phosphor layer of the radiation image conversion panel 23, whereby a number of electrons and / or holes proportional to the amount of radiation absorbed in the stimulable phosphor layer is generated. Occurs and accumulates at the trap level of the stimulable phosphor. That is, a latent image storing the energy of the radiation transmission image is formed. Next, this latent image is excited by light energy to become visible. That is, by irradiating the stimulable phosphor layer with a light source 24 that irradiates light in the visible or infrared region, electrons and / or holes accumulated at the trap level are expelled, and the accumulated energy is emitted as stimulable luminescence. . The intensity of the emitted photostimulated luminescence is proportional to the number of accumulated electrons and / or holes, that is, the intensity of the radiation energy absorbed in the photostimulable phosphor layer of the radiation image conversion panel 23. The optical signal is converted into an electric signal by a photoelectric conversion device 25 such as a photomultiplier tube, reproduced as an image by an image processing device 26, and the image is displayed by an image display device 27.
It is more effective for the image processing device 26 to use a device capable of so-called image processing, image calculation, image storage, storage, and the like, as well as simply reproducing an electric signal as an image signal.

Further, when excited by light energy, it is necessary to separate reflected light of the stimulating phosphor from stimulable luminescence emitted from the stimulable phosphor layer. The photoelectric converter that receives the emitted light is generally 600 nm
From the viewpoint that the sensitivity to the following short-wavelength light energy is increased, it is desirable that the stimulable luminescence emitted from the stimulable phosphor layer has a spectral distribution in the short wavelength region as much as possible. The stimulable phosphor according to the present invention has an emission wavelength range of 300 to 500 nm, while the stimulable excitation wavelength range is 5 to 500 nm.
Although the above conditions are satisfied at the same time since the wavelength is 100 to 900 nm, recently, the downsizing of the diagnostic apparatus has progressed, and the excitation wavelength used for image reading of the radiation image conversion panel has a high output and is easy to make compact. Is preferred, and the wavelength of the laser beam is 680 nm. The stimulable phosphor incorporated in the radiation image conversion panel of the present invention exhibits extremely good sharpness when using an excitation wavelength of 680 nm. is there.

That is, all of the stimulable phosphors according to the present invention emit light having a main peak at 500 nm or less, and the stimulable phosphor easily separates the stimulable excitation light and well matches the spectral sensitivity of the photodetector. As a result, the sensitivity of the image receiving system can be increased.

As the stimulating light source 24, a light source containing the stimulating excitation wavelength of the stimulable phosphor used in the radiation image conversion panel 23 is used. In particular, when a laser beam is used, the optical system is simplified, and the intensity of the stimulating light can be increased, so that the stimulating luminous efficiency can be increased, and more preferable results can be obtained.

As the laser, a He—Ne laser, He
-Cd laser, Ar ion laser, Kr ion laser,
There are an N ₂ laser, a YAG laser and its second harmonic, a ruby laser, a semiconductor laser, various dye lasers, a metal vapor laser such as a copper vapor laser, and the like. Normally, a continuous oscillation laser such as a He-Ne laser or an Ar ion laser is desirable, but a pulse oscillation laser can also be used if the pulse is synchronized with the scanning time of one pixel of the panel. Further, when the separation is performed by using the delay of light emission as disclosed in JP-A-59-22046 without using the filter 28, the pulse oscillation laser is used rather than the modulation using the continuous oscillation laser. It is preferable to use them.

Among the above various laser light sources, semiconductor lasers are particularly preferably used because they are small and inexpensive and do not require a modulator.

Since the filter 28 transmits the stimulating light emitted from the radiation image conversion panel 23 and cuts off the stimulating light, the stimulable phosphor contained in the radiation image conversion panel 23 is used. And the wavelength of the stimulating light source 24.

For example, if the stimulating excitation wavelength is 500 to 900 n
In the case of a practically preferable combination in which the photostimulated emission wavelength is 300 to 500 nm at m, filters such as C-39, C-40, V-40, V-42, and V-42 manufactured by Toshiba Corp.
-44, Corning 7-54, 7-59, Spectrofilm BG-1, BG-3, BG-25, BG
A purple to blue glass filter such as -37 and BG-38 can be used. If an interference filter is used, a filter having an arbitrary characteristic can be selected and used to some extent. As the photoelectric conversion device 25, any device that can convert a change in light amount into a change in an electronic signal, such as a photoelectric tube, a photomultiplier tube, a photodiode, a phototransistor, a solar cell, or a photoconductive element, may be used.

[0071]

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 << Preparation of Radiation Image Conversion Panel Samples 1-6 >> Under the conditions shown in Table 1, a 1 mm thick crystallized glass (manufactured by NEC Corporation) support was vapor-deposited as shown in FIG. Equipment (however, θ1
= 5 degrees and θ2 = 5 degrees) to form a stimulable phosphor layer having a stimulable phosphor (CsBr: Eu).

In the vapor deposition apparatus shown in FIG. 4, an aluminum slit is used, the distance d between the support and the slit is set to 60 cm, and vapor deposition is performed while transporting the support in a direction parallel to the support. The thickness of the phosphor layer is 30
It was adjusted to be 0 μm.

In the vapor deposition, the support was placed in a vapor deposition device, and then a phosphor material (CsBr: Eu) was used.
Was placed in a crucible which was press-formed and water-cooled as a vapor deposition source.

Thereafter, the inside of the evaporator is once evacuated, and then N
_After introducing ₂ gases and adjusting the degree of vacuum to 0.133 Pa,
Vapor deposition was performed while maintaining the temperature of the support (also referred to as the substrate temperature) at about 350 ° C. 300 μm thick stimulable phosphor layer
When it reached m, the vapor deposition was terminated, and then this phosphor layer was subjected to a heat treatment at a temperature of 400 ° C. In a dry air atmosphere, the periphery of the support and the protective layer made of borosilicate glass were sealed with an adhesive to obtain a radiation image conversion panel sample 1 (comparative example) having a structure in which the phosphor layer was sealed.

In the preparation of the radiation image conversion panel sample 1 (comparative example), the radiation image conversion panel samples 2 and 3 (both comparative examples) and the radiation image conversion Panel samples 4 to 6 (all of the present invention) were produced.

The obtained radiation image conversion panel samples 1 to 6
Was evaluated for sharpness as follows.

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

The MTF is obtained by adding C to the radiation image conversion panel sample.
After attaching the TF chart, X-rays of 80 kVp were applied to the radiation image conversion panel sample by 10 mR (distance to the subject:
After irradiation, the CTF chart image was scanned and read using a semiconductor laser having a diameter of 100 μmφ (680 nm: power on the panel: 40 mW). The values in the table are shown by adding the MTF values of 1.0 lp / mm.

Table 1 shows the obtained results.

[0081]

[Table 1]

From Table 1, it is clear that the sample of the present invention has better sharpness (MTF characteristic) than the comparative sample.

[0083]

According to the present invention, a radiation image conversion panel exhibiting high sharpness and a method of manufacturing the radiation image conversion panel can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a stimulable phosphor layer composed of columnar crystals formed on a support.

FIG. 2 is a view showing a state in which a stimulable phosphor layer is formed on a support by vapor deposition.

FIG. 3 is a schematic diagram showing an example of the configuration of the radiation image conversion panel of the present invention.

FIG. 4 is a schematic view showing an example of a method for producing a stimulable phosphor layer on a support by vapor deposition.

[Explanation of symbols]

REFERENCE SIGNS LIST 11 support 12 stimulable phosphor layer 13 columnar crystal 14 gap formed between columnar crystals 15 support holder 21 radiation generator 22 subject 23 radiation image conversion panel 24 stimulating excitation light source 25 emitted by the conversion panel Photoelectric conversion device for detecting stimulated fluorescence 26 Image reproduction device 27 Image display device 28 Filter

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09K 11/85 C09K 11/85 G01T 1/00 G01T 1/00 B F-term (Reference) 2G083 AA03 BB01 CC03 DD02 EE02 4H001 CA04 CA08 XA03 XA04 XA09 XA11 XA12 XA13 XA17 XA19 XA20 XA21 XA28 XA29 XA30 XA31 XA35 XA37 XA38 XA39 XA48 XA49 XA53 XA55 XA56 XA57 XA58 XA59 XA XA XA XA XA X X X X X X YA59 YA60 YA62 YA63 YA64 YA65 YA66 YA67 YA68 YA69 YA70 YA71 YA81

Claims (10)

[Claims] 1. A radiation image conversion panel having a stimulable phosphor layer on a support, wherein at least one stimulable phosphor layer has a stimulable phosphor represented by the following general formula (1). And the stimulable phosphor layer is formed so as to have a film thickness of 50 μm or more by a vapor deposition method (also referred to as a vapor deposition method), and has a wavelength as excitation light of the stimulable phosphor. 6
A radiation image conversion panel, wherein the transmittance or reflectance of the stimulable phosphor layer is 20% or more when 80 nm light is incident. General formula (1) M ¹ X.aM ² X ′ ₂ .bM ³ X ″ ₃ : eA wherein M ¹ is at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs Yes, M ² is Be, Mg, Ca, Sr, Ba, Zn, C
d, at least one divalent metal selected from the group consisting of Cu and Ni, and M ³ is Sc, Y, La, Ce,
Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
at least one trivalent metal selected from the group consisting of o, Er, Tm, Yb, Lu, Al, Ga and In, wherein X, X 'and X "are selected from the group consisting of F, Cl, Br and I At least one type of halogen,
A is Eu, Tb, In, Cs, Ce, Tm, Dy, P
r, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y,
At least one metal selected from the group consisting of Tl, Na, Ag, Cu and Mg, and a, b and e are respectively 0 ≦ a <0.5, 0 ≦ b <0.5, 0 < e ≦ 0.
Represents a numerical value in the range of 2. ] 2. The radiation image conversion panel according to claim 1, wherein M ¹ in the general formula (1) is at least one kind of alkali metal selected from the group consisting of K, Rb and Cs. 3. X in the general formula (1) is Br and I
The radiation image conversion panel according to claim 1, wherein the radiation image conversion panel is at least one halogen selected from the group consisting of: 4. M ² in the general formula (1) is Be, M
The radiation image conversion panel according to any one of claims 1 to 3, wherein the radiation image conversion panel is at least one divalent metal selected from g, Ca, Sr, and Ba. 5. A M ³ in the general formula (1) is Y, Ce,
Sm, Eu, Al, La, Gd, Lu, Ga and In
The radiation image conversion panel according to any one of claims 1 to 4, wherein the radiation image conversion panel is at least one kind of trivalent metal selected from the group consisting of: 6. In the formula (1), b is 0 ≦ b ≦ 10.
The radiation image conversion panel according to any one of claims 1 to 5, wherein the radiation image conversion panel is ^-2 . 7. In the general formula (1), A is Eu, C
The radiation image conversion panel according to any one of claims 1 to 6, wherein the radiation image conversion panel is at least one metal selected from the group consisting of s, Sm, Tl, and Na. 8. The radiation image conversion panel according to claim 1, wherein the stimulable phosphor has a columnar crystal. 9. The radiation image conversion panel according to claim 8, wherein the columnar crystal has a stimulable phosphor represented by the following general formula (2) as a main component. General formula (2) CsX: A [wherein X represents Br or I, and A represents Eu, In, T
represents b or Cs. ] 10. A radiation image conversion panel, wherein the stimulable phosphor layer is formed by a vapor phase growth method in producing the radiation image conversion panel according to any one of claims 1 to 9. Manufacturing method.