JP2002357699A - Radiological image conversion panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiological image conversion panel with excellent sharpness, contrast and luminance. SOLUTION: This radiological image conversion panel comprises a phosphor sheet provided on a phosphor layer containing a photostimulable phosphor on a supported body, and a protective layer provided so as to cover the phosphor sheet. This panel further comprises a colored layer A between the support body and the phosphor layer, and a colored layer B between the phosphor layer and the protective layer, and the absorbance of the colored layer B is higher than that of the colored layer B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image conversion panel excellent in sharpness, contrast and brightness.

[0002]

2. Description of the Related Art Radiation images such as X-ray images are widely used in fields such as disease diagnosis. As a method of obtaining this X-ray image, X-rays that have passed through a subject are irradiated on a phosphor layer (fluorescent screen) to generate visible light, and then the visible light is used in the same manner as when a normal photograph is taken. A so-called radiographic system in which a visible silver image is obtained by irradiating a silver halide photographic light-sensitive material and then performing a developing process to obtain a visible silver image is widely used.

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

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

Specifically, for example, US Pat.
A radiation image conversion method using a stimulable phosphor (hereinafter, also simply referred to as a phosphor) as described in JP-A No. 9,527 and JP-A-55-12144 is known.

In this method, a radiation image conversion panel containing a stimulable phosphor is used. The radiation transmitted through the subject is applied to the stimulable phosphor layer of the radiation image conversion panel, and each part of the subject is irradiated with the radiation. Accumulates radiation energy corresponding to the radiation transmission density, and then excites the stimulable phosphor with electromagnetic waves (excitation light) such as visible light and infrared light in a time-series manner, thereby accumulating in the stimulable phosphor. The emitted radiation energy is emitted as stimulated emission, and a signal based on the intensity of the light is photoelectrically converted, for example, to obtain an electric signal, and this signal is used as a recording material such as a silver halide photographic material, a CRT, or the like. Is reproduced as a visible image on a display device.

According to the above-described radiographic image reproducing method, a radiographic image with a much smaller exposure dose and an abundant amount of information as compared with a radiographic method using a combination of a conventional radiographic film and an intensifying screen. Can be obtained.

As described above, the stimulable phosphor is a phosphor that emits stimulable light when irradiated with radiation and then with excitation light. However, in practice, the stimulable phosphor has a wavelength in the range of 400 to 900 nm. Phosphors that exhibit stimulated emission in the wavelength range of 300 to 500 nm by light are generally used.

The radiation image conversion panel comprises a support and a stimulable phosphor layer or a self-supporting stimulable phosphor layer provided on the surface of the support. Some are composed of a stimulable phosphor and a binder that supports and disperse the stimulable phosphor, and others are composed only of aggregates of a stimulable phosphor formed by a vapor deposition method or a sintering method. In addition, a polymer in which the gap between the aggregates is impregnated with a polymer substance is also known. Furthermore, on the surface of the stimulable phosphor layer opposite to the support side,
Usually, a protective layer film made of a polymer film or an inorganic vapor deposition film is provided.

In the reading step in the radiation image recording / reproducing method, in general, excitation light is irradiated from one surface side of the radiation image conversion panel, and the stimulating light (stimulating light) emitted from the phosphor particles is converted into the excitation light. A method of taking out light with a light-collecting guide provided on the irradiation side, photoelectrically converting the light, and reading the light is used. However, when it is desired to extract as much stimulable light emitted from the stimulable phosphor particles as possible, or when the accumulated image of the radiation energy formed in the stimulable phosphor layer has an energy intensity in the depth direction within the layer. When it is desired to obtain a change in the energy intensity distribution as radiation image information when the distribution is changing, a method of condensing photostimulated light from both sides of the radiation image conversion panel (double-sided condensing reading method) is used. Sometimes. This double-sided condensing reading method is described in, for example, JP-A-55-87970.

[0011] The superiority of the radiation image conversion system using the radiation image conversion panel largely depends on the stimulable emission luminance (also called sensitivity) of the panel and the sharpness of the obtained image. Thus, the properties of the stimulable phosphor used are said to have a significant effect.

Generally, a laser beam having high beam convergence is used as a light source of the excitation light of the radiation image conversion panel. However, when the laser beam is scanned through a protective layer made of a polymer film such as PET, Scattering of the excitation laser light inside the protective layer film, the periphery of the radiation image conversion panel, or a support plate provided to support the radiation image conversion panel, and further transport and read the radiation image conversion panel Irradiation of the excitation laser light in the provided radiation image reading apparatus may occur. The excitation light that has been irregularly reflected is irradiated on the radiation image conversion panel surface sequentially while scanning with the excitation light, and when reading, the stimulability of a place away from the place where the excitation light was irradiated and the stimulated emission was emitted. Since the phosphor surface is also excited to emit stimulated emission, there has been a problem that the resulting image has reduced sharpness and contrast.

Particularly, a stretched film such as a polyethylene terephthalate film or a polyethylene naphthalate film has a high refractive index despite having excellent physical properties as a protective layer in terms of transparency, barrier properties and strength. Therefore, part of the excitation light incident on the inside of the protective film is repeatedly reflected at the upper and lower interfaces of the film and propagates to a place apart from the scanned place, emits stimulated emission, sharpness, and contrast Decrease. Excitation light that has propagated inside the protective layer and at the interface between the protective layers is reflected and scattered at the periphery of the radiation image conversion panel to emit stimulated emission, resulting in reduced sharpness and contrast. Furthermore, the excitation light reflected in the opposite direction to the phosphor surface at the upper and lower interfaces of the protective layer is also re-reflected between the photodetectors and peripheral members, and the stimulable phosphor surface at a location farther from the scanned location is also reflected. Exciting to emit stimulating luminescence, further sharpness,
And the contrast is reduced. Since the excitation light is coherent light of long wavelength from red to infrared, the amount absorbed in the space inside the protective film and the reader is small unless it actively absorbs scattered light and reflected light. It propagates to the place and deteriorates sharpness and contrast.

In order to prevent the sharpness or the deterioration of the contrast described above, a method of thinning the protective film and shortening the propagation distance of the excitation light inside the protective film can be considered. There is a problem in that the moisture resistance and the scratch resistance are reduced due to the thinning of the film. Regarding the enhancement of sharpness and contrast, Japanese Patent Publication No. 59-23400 discloses that any one of a support, an undercoat layer, a phosphor layer, an intermediate layer, and a protective layer of a radiation image conversion panel is colored with an excitation light absorbing color. JP-A-60-200200 discloses a method of coloring the adhesive layer between the phosphor layer and the protective layer. However, when the sharpness and the contrast are enhanced by these methods, the above-described image unevenness or line There is a problem that the shape noise becomes more remarkable.

If the sharpness and contrast deteriorate, and the image unevenness and the linear noise are severe, it becomes a fatal defect for the radiation image conversion panel used for diagnosing the disease. ing.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a radiation image conversion panel having excellent sharpness, contrast, and brightness.

[0017]

The above object of the present invention has been attained by the following constitutions.

1. In a radiation image conversion panel having a phosphor sheet provided with a phosphor layer containing a stimulable phosphor on a support and a protective layer provided so as to cover the phosphor sheet, the support and the phosphor A colored layer A between the phosphor layer and the protective layer, and a colored layer B between the phosphor layer and the protective layer, wherein the absorbance of the colored layer A is higher than the absorbance of the colored layer B. Image conversion panel.

2. 2. The radiation according to claim 1, wherein the spectral absorption characteristics of the colored layer A and the colored layer B are higher in absorbance on the long wavelength side (600 to 700 nm) than on the short wavelength side (370 to 500 nm). Image conversion panel.

3. In a radiation image conversion panel having a phosphor sheet provided with a phosphor layer containing a stimulable phosphor on a support, and a low refractive index layer and a protective layer provided so as to cover the phosphor sheet, A colored layer A between the phosphor and the phosphor layer, a colored layer B between the phosphor layer and the protective layer, and the respective refractive indices of the colored layer A and the colored layer B; A radiation image conversion panel, wherein the refractive index of the refractive index layer and the refractive index of the phosphor layer have the relationship represented by the above formula (1).

The inventors of the present invention have conducted intensive studies in view of the above problems, and have investigated and analyzed the causes of deterioration in the sharpness and contrast of the radiation image conversion panel. By providing colored layers on both sides, it is found that sharpness, contrast, and brightness are improved,
Furthermore, by setting the density balance and spectral absorption characteristics of each colored layer to specific conditions, and by setting the balance of the refractive index of each layer constituting the radiation image conversion panel to an optimal relationship, excellent sharpness and contrast are obtained. And brightness can be obtained, and the present invention has been reached.

Hereinafter, the present invention will be described in detail. The radiation image conversion panel according to the present invention is characterized in that a colored layer A is provided between the support and the phosphor layer, and a colored layer B is provided between the phosphor layer and the protective layer. .

Specifically, it is preferable that the coloring layer A is provided between the support and the phosphor layer and is adjacent to the lower portion of the phosphor layer. Further, the coloring layer B is provided between the phosphor layer and the protective layer,
Preferably, it is provided between the phosphor layer and the low refractive index layer, and particularly preferably, it is adjacent to the upper portion of the phosphor layer.

The colored layer in the present invention is a layer colored so as to absorb excitation light, and is also called an excitation light absorption layer.
A layer containing a colorant that selectively absorbs excitation light.

A method for improving the sharpness by coloring the radiation image conversion panel is disclosed in JP-B-59-23400, which describes the method of forming the support, undercoat layer, phosphor layer, intermediate layer and protective layer of the radiation image conversion panel. Although described as an example of various embodiments in which each layer is colored, the effect is insufficient due to a decrease in luminance and the like.

That is, it was found that when a dye was simply contained in the phosphor layer, the sharpness was improved, but the luminance was deteriorated. This time, as a result of various investigations, we found that by providing a colored layer provided to absorb the excitation light on both sides of the phosphor layer, brightness and sharpness were simultaneously improved, and a more uniform image was obtained. The result was reached.

According to the first aspect of the present invention, the colored layer A,
As the absorbance balance of B, the absorbance of the colored layer A is set to be higher than the absorbance of the colored layer B. Preferably, the absorbance of the colored layer A is 1.1 times the absorbance of the colored layer B.
To 10.0 times, particularly preferably 1.5 to 5.0 times.
It is twice.

In the present invention, the absorbance of the colored layer refers to the short wavelength side (370 to 500 nm) and the long wavelength side (600 to 70 nm).
0 nm).

By setting the absorbance balance of the colored layer to the relationship defined in claim 1, without impairing the luminance,
Contrast and sharpness can be improved.

According to the second aspect of the present invention, the spectral absorption characteristics of the colored layers A and B are shorter on the short wavelength side (370 to 500 nm).
m) is characterized by a higher absorbance on the long wavelength side (600 to 700 nm) than that on m), preferably the absorbance on the long wavelength side is 1.1 to 10.0 times the absorbance on the short wavelength side, and particularly preferred. Is 1.5 to 5.0 times.

In the colored layer according to the present invention, it is necessary that the absorbance at the emission peak wavelength of the stimulated emission be smaller than the absorbance at the peak wavelength of the excitation light. The difference is preferably large.

As the coloring material used in the coloring layer according to the present invention, those having a characteristic of absorbing the excitation light in the wavelength region of the excitation light of the radiation image conversion panel are used. It is necessary that the absorbance at the emission peak wavelength of the stimulated emission be smaller than the absorbance of.

One of the forms of the colored layer used in the present invention is preferably a colored resin layer formed by coating on a support, and the resin is preferably made of polyester, polyurethane, acrylic, or polyvinyl butyral. It is desirable to be composed of an epoxy resin. As another method, it can be formed on the surface of a support or a phosphor layer to be coated by a multilayer film deposition method.

In the colored layer according to the present invention, what kind of coloring agent is used depends on the kind of stimulable phosphor used in the radiation image conversion panel. , The wavelength is 400 to 90
300-500 nm by excitation light in the range of 0 nm
A phosphor that emits light in the above wavelength range is used. For this reason, as a coloring agent used for the excitation light absorbing layer, a blue to green organic or inorganic coloring agent is usually used.

The coloring agents usable in the present invention include, for example, JP-A-47-30330 and JP-A-56-55.
52, a perylene pigment described in JP-A-47-3033
Quinacridone pigments described in JP-A No.
Bisbenzimidazole pigments described in JP-A-8543, JP-A-47-18544, JP-A-55-98754, and JP-A-5-98754.
5-126254 and 55-163543, aromatic polycondensed ring compounds described in JP-B-44-16373.
No. 48-30513, JP-A-56-32465.
Azo pigments described in Japanese Patent Application Publication No. 50-7434,
JP-A-47-37548, JP-A-55-11715, JP-A-56-1944, JP-A-56-9752, and JP-A-56-23.
Disazo pigments described in JP-A Nos. 52 and 56-80050, JP-B Nos. 44-12671 and 40-2780.
No., No. 52-1667, No. 46-30035, No. 4
9-17535, JP-A-49-11136 and JP-A-49-11136
-99142, 51-109841, 57-1
And phthalocyanine pigments described in JP-A-48745.

These colorants are commercially available, for example, Pomelo Fast Blue 3G (manufactured by Hoechst),
Estrol Brill Blue N-3RL (Sumitomo Chemical Co., Ltd.)
Sumiacryl Blue F-GSL (Sumitomo Chemical Co., Ltd.)
D & C Blue No. 1 (National Aniline Co., Ltd.), Spirit Blue (Hodogaya Chemical Co., Ltd.), Oil Blue No. 603 (manufactured by Orient Co., Ltd.), Kiton Blue A (manufactured by Ciba-Geigy), Eizenkatilon Blue GLH (manufactured by Hodogaya Chemical Co., Ltd.), Lake Blue A,
F, H (Kyowa Sangyo Co., Ltd.), Rhodalin Blue 6GX
(Kyowa Sangyo Co., Ltd.), Brimocyanin 6GX (Inabata Sangyo Co., Ltd.), Brill Acid Green 6BH (Hodogaya Chemical Co., Ltd.), Cyanine Blue BNRS (Toyo Ink Co., Ltd.), Lionol Blue SL (Toyo Ink Co., Ltd.
Manufactured).

These can be used alone or in combination of two or more. Among these compounds, phthalocyanine compounds are preferable from the viewpoint of the wavelength range. In the present invention, examples of the inorganic colorant include ultramarine blue, cobalt blue, cerulean blue, chromium oxide, zinc oxide, titanium oxide, zirconium oxide, and the like, and particularly, copper phthalocyanine is preferable.

In the invention according to claim 3, the refractive index of the colored layer A and the colored layer B, the refractive index of the protective layer and the low refractive index layer, and the refractive index of the phosphor layer are defined by the above-mentioned formula (1). This is a feature. With this refractive index configuration, scattering of excitation light can be minimized, and high sharpness and contrast can be obtained.

In order for each constituent layer to have the order of the refractive index specified in the present invention, the polymer resin used in each layer, the type of additive,
This can be achieved by appropriately adjusting the amount of addition and the like. Further, the refractive index referred to in the present invention is a value obtained by measuring each single layer with a commercially available refractometer. As the refractometer, for example, an automatic birefringence meter KOBRA-21A is used.
DH (manufactured by Oji Scientific Instruments).

Next, the phosphor layer will be described in detail. The phosphor layer is roughly classified into a phosphor layer formed by applying a coating solution composed of a phosphor and a polymer resin that disperses and retains the phosphor onto a support (hereinafter referred to as a coating type phosphor). And a phosphor layer formed by a vapor deposition method (hereinafter also referred to as a vapor-deposited phosphor layer).

First, the coating type phosphor layer will be described. The coating type phosphor layer is mainly composed of phosphor particles and a polymer resin, and is formed by coating on a support using a coater.

As the stimulable phosphor that can be used in the coating type phosphor layer, a phosphor that emits stimulable light in the wavelength range of 300 to 500 nm by excitation light having a wavelength in the range of 400 to 900 nm is generally used. Is used regularly.

The following are examples of phosphors that can be preferably used in the coating type phosphor layer according to the present invention, but the present invention is not limited to these.

[0044] (1) are described in JP _{55-12145 (Ba 1-X, M} (II) X) FX: yA, ( in the formula,
M (II) is at least one of Mg, Ca, Sr, Zn and Cd, X is at least one of Cl, Br and I, A is Eu, Tb, Ce, Tm, Dy, P
at least one of r, Ho, Nd, Yb, and Er, and 0 ≦ x ≦ 0.6, and y is 0 ≦ y ≦ 0.
2) a rare earth element-activated alkaline earth metal fluorohalide phosphor represented by the following composition formula; and the phosphor may contain the following additives.

A) X ', BeX ", M (III) X'" ₃ described in JP-A-56-74175, wherein
X ', X "and X""are each at least one of Cl, Br and I, and M (III) is a trivalent metal. B) Be described in JP-A-55-160078.
O, MgO, CaO, SrO, BaO, ZnO, Al ₂
O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ , SiO ₂ , Ti
O ₂ , ZrO ₂ , GeO ₂ , SnO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅
And metal oxides such as ThO ₂ c) Z described in JP-A-56-116777
r, Sc d) Be described in JP-A-57-23673. e) As described in JP-A-57-23675.
Sif) M. described in JP-A-58-206678.
L, wherein M is at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs, and L is Sc, Y, La, Ce, Pr, Nd, Pm, Sm
m, Gd, Tb, Dy, Ho, Er, Tm, Yb, L
g) at least one trivalent metal selected from the group consisting of u, Al, Ga, In, and Tl. g) A calcined product of a tetrafluoroborate compound described in JP-A-59-27980; 59-2728
No. 9 baked products of salts of monovalent or divalent metals of hexafluorosilicic acid, hexafluorotitanic acid and hexafluorozirconic acid;
479, wherein X 'is C
h) V, C described in JP-A-59-56480.
transition metals such as r, Mn, Fe, Co and Ni; M (I) X 'described in JP-A-59-75200;
M '(II) X " ₂ , M (III) X'" ₃ , A, where M
(I) is at least one alkali metal selected from the group consisting of Li, Na, K, Rb, and Cs;
M '(II) represents at least one divalent metal selected from the group consisting of Be and Mg, and M (III) represents Al, G
a, In, and at least one trivalent metal selected from the group consisting of Tl, A is a metal oxide,
X ', X "and X'" are each at least one halogen selected from the group consisting of F, Cl, Br and I. i) M described in JP-A-60-101173
(I) X ′, wherein M (I) is at least one alkali metal selected from the group consisting of Rb and Cs,
X 'is at least one halogen selected from the group consisting of F, Cl, Br and I j) M (I) described in JP-A-61-23679.
I) 'X' ₂ · M (II) 'X " ₂ , where M (II)' is B
X 'and X "are each at least one halogen selected from the group consisting of Cl, Br and I, and X' {X ";
Further, LnX ″ ₃ described in JP-A-61-264084, wherein Ln is Sc, Y, La, Ce,
Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, E
X "is at least one rare earth element selected from the group consisting of r, Tm, Yb and Lu; X" is F, Cl, Br
And at least one halogen selected from the group consisting of

[0046] (2) JP-60-84381 is described in JP _{M (II) X 2 · aM} (II) X '2: xEu 2+ ( wherein, M (II) is Ba, Sr and Ca X and X 'are at least one halogen selected from the group consisting of Cl, Br and I, and X ≠ X'; and a Is 0.1 ≦ a ≦ 10.0, x is 0 <x ≦
0.2), a divalent europium-activated alkaline earth metal halide phosphor represented by the following composition formula; and the phosphor may contain the following additives.

A) M (I) X 'described in JP-A-60-166379, wherein M (I) is Rb and C
X 'is at least one halogen selected from the group consisting of F, Cl, Br and I. b) described in JP-A-60-221483. K
X ″, MgX ′ ″ ₂ , M (III) X ″ ″ ₃ , wherein M (II
I) is at least one trivalent metal selected from the group consisting of Sc, Y, La, Gd and Lu;
X ′ ″ and X ″ ″ are each F, Cl, Br and I
C) at least one halogen selected from the group consisting of: c) B described in JP-A-60-228592;
Si described in JP-A-60-228593
Oxides such as O ₂ and P ₂ O ₅ , LiX ″ and NaX ″ described in JP-A-61-120882, wherein X ″ is at least one selected from the group consisting of F, Cl, Br and I. D) a kind of halogen d) Si described in JP-A-61-120883
O: Sn described in JP-A-61-120885
X " ₂ , wherein X" is at least one halogen selected from the group consisting of F, Cl, Br and I. e) Cs described in JP-A-61-235486.
X ", SnX"" ₂ , wherein X" and X "" are each at least one halogen selected from the group consisting of F, Cl, Br and I;
CsX ″, Ln ³⁺ described in No. 5487, wherein
X "is at least one halogen selected from the group consisting of F, Cl, Br and I; Ln is Sc, Y, C
e, Pr, Nd, Sm, Gd, Tb, Dy, Ho, E
It is at least one rare earth element selected from the group consisting of r, Tm, Yb and Lu.

(3) LnOX: xA described in JP-A-55-12144 (where Ln is La, Y, G
at least one of d and Lu; X is Cl, B
at least one of r and I; A is Ce and T
b is at least one; x is 0 <x <0.1). A rare earth element-activated rare earth oxyhalide phosphor represented by a composition formula:

(4) M (II) OX: xCe described in JP-A-58-69281 (where M (II) is P
r, Nd, Pm, Sm, Eu, Tb, Dy, Ho, E
at least one metal oxide selected from the group consisting of r, Tm, Yb, and Bi; X is at least one of Cl, Br, and I; and x is 0 <x <0.1.
The cerium-activated trivalent metal oxyhalide phosphor represented by the following composition formula:

(5) M (I) X: xBi described in JP-A-62-25189 (wherein M (I) is at least one alkali metal selected from the group consisting of Rb and Cs) X is at least one halogen selected from the group consisting of Cl, Br and I; and x is a numerical value in the range of 0 <x ≦ 0.2). Alkali metal halide phosphor.

(6) M (II) ₅ (PO ₄ ) ₃ X: xEu ²⁺ described in JP-A-60-141783 (wherein
M (II) is at least one alkaline earth metal selected from the group consisting of Ca, Sr and Ba; X is F;
At least one halogen selected from the group consisting of Cl, Br and I; and x is a numerical value in the range of 0 <x ≦ 0.2) divalent europium-activated alkaline earth metal represented by a composition formula Halophosphate phosphor.

(7) M (II) ₂ BO ₃ X: xEu ²⁺ described in JP-A-60-157099 (wherein M (I
I) is at least one alkaline earth metal selected from the group consisting of Ca, Sr and Ba; X is Cl, B
at least one halogen selected from the group consisting of r and I; x is a numerical value in the range of 0 <x ≦ 0.2) divalent europium-activated alkaline earth metal haloboric acid represented by the composition formula: Salt phosphor.

(8) M (II) ₂ (PO ₄ ) ₃ X: xEu ²⁺ described in JP-A-60-157100 (wherein
M (II) is at least one alkaline earth metal selected from the group consisting of Ca, Sr and Ba;
at least one halogen selected from the group consisting of l, Br and I; and x is a numerical value in the range of 0 <x ≦ 0.2) divalent europium-activated alkaline earth metal represented by a composition formula Halophosphate phosphor.

(9) M (II) HX: xEu ²⁺ described in JP-A-60-217354 (wherein M (II) is at least one member selected from the group consisting of Ca, Sr and Ba) X is at least one halogen selected from the group consisting of Cl, Br and I; and x is a numerical value in the range of 0 <x ≦ 0.2). Bivalent europium activated alkaline earth metal hydride halide phosphor.

(10) LnX ₃ · aLn'X ' ₃ : xCe ³⁺ described in JP-A-61-21173, wherein Ln and Ln' are each composed of Y, La, Gd and Lu X and X ′ are each at least one halogen selected from the group consisting of F, Cl, Br and I, and X ≠ X ′; and a is 0.1 <a
≦ 10.0, and x is a numerical value in the range of 0 <x ≦ 0.2). The cerium-activated rare earth composite halide phosphor represented by the composition formula:

(11) LnX ₃ .aM (I) X'3: xCe ³⁺ , described in JP-A-61-21822
(Wherein, Ln is at least one rare earth element selected from the group consisting of Y, La, Gd and Lu;
(I) is at least one alkali metal selected from the group consisting of Li, Na, K, Cs and Rb; X and X 'are at least one halogen selected from the group consisting of Cl, Br and I, respectively. And a is a numerical value in the range of 0 <a ≦ 10.0, and x is 0 <x ≦
A cerium-activated rare earth composite halide phosphor represented by the following composition formula:

(12) LnPO ₄ .aLnX ₃ : xCe ³⁺ described in JP-A-61-40390 (wherein
Ln is at least one rare earth element selected from the group consisting of Y, La, Gd and Lu; X is F, Cl,
At least one halogen selected from the group consisting of Br and I; and a is a numerical value in the range of 0.1 ≦ a ≦ 10.0, and x is a numerical value in the range of 0 <x ≦ 0.2. ) A cerium-activated rare earth halophosphate phosphor represented by the composition formula:

(13) CsX: aRbX ': xEu ²⁺ , described in JP-A-61-236888.
Wherein X and X ′ are each at least one halogen selected from the group consisting of Cl, Br and I; and a is a numerical value in the range of 0 <a ≦ 10.0;
x is a numerical value in the range of 0 <x ≦ 0.2). A divalent europium-activated cesium rubidium halide phosphor represented by a composition formula:

(14) M (II) X ₂ .aM (I) X ': xE described in JP-A-61-236890
u ²⁺ , wherein M (II) is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; M (I) is selected from the group consisting of Li, Rb and Cs X and X ′ are each at least one halogen selected from the group consisting of Cl, Br and I; and a is a numerical value in the range of 0.1 ≦ a ≦ 20.0. , X is 0 <x
≦ 0.2) is a divalent europium-activated composite halide phosphor represented by the composition formula:

Among the stimulable phosphors described above, the stimulable phosphor particles preferably contain iodine. For example, divalent europium-activated alkaline earth metal fluorinated halide containing iodine Phosphor, divalent europium-activated alkaline earth metal halide phosphor containing iodine, rare earth activated rare earth oxyhalide phosphor containing iodine, and bismuth activated alkali metal halogen containing iodine Phosphor-based phosphors are preferred because they exhibit high-brightness stimulated emission.
Preferably, it is an additional BaFI compound.

In the present invention, examples of the binder used in the phosphor layer include proteins such as gelatin, polysaccharides such as dextran, and natural high molecular substances such as gum arabic; and polyvinyl butyral, polyvinyl acetate. , Nitrocellulose, ethylcellulose, vinylidene chloride-vinyl chloride copolymer, polyalkyl (meth) acrylate, vinyl chloride-vinyl acetate copolymer, polyurethane, cellulose acetate butyrate,
Examples of the binder include synthetic polymers such as polyvinyl alcohol and linear polyester. In the invention according to claim 4, the binder is a resin mainly composed of a thermoplastic elastomer. It is characterized in that, as the thermoplastic elastomer, for example, the above-mentioned polystyrene-based thermoplastic elastomer, polyolefin-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, polybutadiene Thermoplastic elastomer, ethylene vinyl acetate thermoplastic elastomer, polyvinyl chloride thermoplastic elastomer, natural rubber thermoplastic elastomer, fluoro rubber thermoplastic elastomer, polyisoprene thermoplastic elastomer, chlorine Polyethylene-based thermoplastic elastomer, a styrene - butadiene rubber and silicone rubber type thermoplastic elastomers, and the like. Of these, polyurethane-based thermoplastic elastomers and polyester-based thermoplastic elastomers have good dispersibility because of their strong bonding force with the phosphor, are also rich in ductility, and have good flexibility against radiation intensifying screens. Is preferred. In addition, these binders may be crosslinked with a crosslinking agent.

The mixing ratio between the binder and the stimulable phosphor in the coating solution varies depending on the set value of the haze ratio of the intended radiation image conversion panel, but is preferably 1 to 20 parts by mass with respect to the phosphor. Is more preferably 2 to 10 parts by mass.

Examples of the organic solvent used for preparing the stimulable phosphor layer coating solution include methanol, ethanol, and the like.
Lower alcohols such as isopropanol and n-butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters of lower fatty acids such as methyl acetate, ethyl acetate and n-butyl acetate with lower alcohols; dioxane; ethylene glycol monoethyl Examples thereof include ethers, ethers such as ethylene glycol monomethyl ether, aromatic compounds such as triol and xylol, halogenated hydrocarbons such as methylene chloride and ethylene chloride, and mixtures thereof.

The coating solution contains a dispersing agent for improving the dispersibility of the phosphor in the coating solution, and a binder between the binder and the phosphor in the stimulable phosphor layer after formation. Various additives such as a plasticizer for improving the bonding strength may be mixed. Examples of dispersants used for such purposes include phthalic acid, stearic acid, caproic acid, and lipophilic surfactants. Examples of the plasticizer include phosphoric esters such as triphenyl phosphate, tricresyl phosphate and diphenyl phosphate; phthalic esters such as diethyl phthalate and dimethoxyethyl phthalate; ethylphthalylethyl glycolate, butylphthalylbutyl glycolate; And polyesters of polyethylene glycol and aliphatic dibasic acids, such as polyesters of triethylene glycol and adipic acid, and polyesters of diethylene glycol and succinic acid. In addition, in the stimulable phosphor layer coating solution, for the purpose of improving the dispersibility of the stimulable phosphor particles, a dispersant such as stearic acid, phthalic acid, caproic acid, and a lipophilic surfactant is mixed. Is also good.

The coating solution for the stimulable phosphor layer is prepared, for example, by using a ball mill, a bead mill, a sand mill, an attritor, a three-roll mill, a high-speed impeller disperser, a Kady.
This is performed using a dispersing device such as a mill or an ultrasonic dispersing machine.

A coating film is formed by uniformly applying the coating solution prepared as described above to the surface of a support described later. As a coating method that can be used, usual coating means, for example, a doctor blade, a roll coater, a knife coater, a comma coater, a lip coater and the like can be used.

The coating film formed by the above means is then heated and dried to complete the formation of the stimulable phosphor layer on the support. The thickness of the stimulable phosphor layer varies depending on the intended characteristics of the radiation image conversion panel, the type of the stimulable phosphor, the mixing ratio of the binder and the phosphor, and the like.
0 to 1000 μm, more preferably 10 to 500
μm.

Next, the deposition type phosphor layer will be described.
Examples of the stimulable phosphor that can be used in the vapor-deposited phosphor layer include phosphors represented by BaSO ₄ : Ax described in JP-A-48-80487 and JP-A-48-80487.
MgSO described in JP 80 488 _4: phosphor represented by Ax, are described in JP-A-48-80489 SrS
Phosphor represented by O ₄ : Ax, JP-A-51-29889
Na ₂ SO ₄ as described in JP, CaSO ₄ and BaS
A phosphor obtained by adding at least one of Mn, Dy and Tb to O ₄ or the like, a phosphor such as BeO, LiF, MgSO ₄ and CaF ₂ described in JP-A-52-30487;
Li ₂ B ₄ O as described in JP-A No. 53-39277
₇ : Phosphor such as Cu, Ag, etc., Li ₂ O · (Be ₂ O ₂ ) x: Cu, A described in JP-A-54-47883.
g, etc., SrS: Ce, Sm, SrS: Eu, Sm, described in U.S. Pat. No. 3,859,527.
La ₂ O ₂ S: Eu, Sm and (Zn, Cd) S: Mnx
The phosphor represented by Also, Japanese Patent Laid-Open No. 55-12
No. 142, a ZnS: Cu, Pb phosphor;
A barium aluminate phosphor whose general formula is BaO.xAl ₂ O ₃ : Eu, and whose general formula is M (II) O.xS
An alkaline earth metal silicate-based phosphor represented by iO ₂ : A is exemplified.

An alkaline earth fluoride halide fluorescent compound represented by the general formula (Ba _{1 -xy} Mg _x C a _y ) F _x : Eu ²⁺ described in JP-A-55-12143. The general formula described in JP-A-55-12144 is LnO
X: a phosphor represented by xA, and the general formula described in JP-A-55-12145 is represented by (Ba _1-x M (II) _x ) F _x :
The phosphor represented by yA, the general formula described in JP-A-55-84389, and the phosphor represented by BaFX: xCe, yA, the general formula described in JP-A-55-160078. M (II) FX · xA: a rare earth element-activated divalent metal fluorohalide phosphor represented by yLn, a general formula Z
a phosphor represented by nS: A, CdS: A, (Zn, Cd) S: A, X, and any one of the following general formulas xM ₃ (PO ₄ ) ₂ described in JP-A-59-38278. _{· NX 2: yA xM 3 (} PO 4) 2: phosphor represented by yA, following one of the general formulas described in _{JP-a-59-155487 nReX 3 · mAX '2:} xEu nReX 3 · MAX _'2: xEu, phosphor represented by the following general formula M (I) X · aM that is described in JP-a-61-72087 (II) X represented by _{ySm' 2 · bM (III)} X "3 : C
A. The alkali halide phosphor represented by A.
General formula M (I) X: x described in No. 228400
Bismuth-activated alkali halide phosphors represented by Bi and the like can be mentioned.

In particular, the alkali halide phosphor is deposited,
It is preferable because a columnar stimulable phosphor layer can be formed by a method such as sputtering.

As described above, among the alkali halide phosphors, RbBr and CsBr-based phosphors are preferable in that they have high luminance and high image quality, and among them, CsBr-based phosphors are particularly preferable.

As a method for forming a vapor-deposited phosphor layer on a support, for example, a vapor of a stimulable phosphor or a raw material thereof is supplied onto a support at a specific incident angle, and vapor deposition or the like is performed. A stimulable phosphor layer composed of independent elongated columnar crystals can be obtained by a method of phase growth (deposition). The columnar crystal can grow at a growth angle that is about half the incident angle of the vapor flow of the stimulable phosphor during vapor deposition. In addition, a molecular vapor deposition film can be provided by vapor deposition at around normal temperature.

The method of supplying the vapor flow of the stimulable phosphor at a certain incident angle with respect to the surface of the support may be such that the support is arranged to be inclined with respect to the crucible in which the evaporation source is charged, or The crucible and the crucible are placed in parallel with each other, and only the oblique component is vapor-deposited on the support by a slit or the like from the evaporation surface of the crucible charged with the evaporation source.

In these cases, it is appropriate that the distance between the shortest part between the support and the crucible is set to approximately 10 cm to 60 cm in accordance with the average range of the stimulable phosphor. In addition, the thickness of the columnar crystals tends to become thinner as the temperature of the support becomes lower.

The stimulable phosphor serving as an evaporation source is charged into a crucible after being uniformly dissolved or formed by pressing or hot pressing. At this time, it is preferable to perform a degassing treatment. The method of evaporating the stimulable phosphor from the evaporation source is performed by scanning with an electron beam emitted from an electron gun, but may be performed by other methods.

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

Further, an activator may be added to the base of the phosphor later. For example, after depositing only RbBr as a base, Tl as an activator may be doped.
That is, since the crystals are independent, it is possible to sufficiently dope even if the film is thick, and crystal growth hardly occurs.
This is because F does not decrease.

The doping can be carried out by thermally diffusing a doping agent (activator) into the formed base layer of the phosphor and by ion implantation.

In the stimulable phosphor layer composed of these columnar crystals, in order to reduce the haze ratio, the size of the columnar crystals (the size of each columnar crystal when the columnar crystal is observed from a plane parallel to the support) is reduced. It is the average value of the diameter of the cross-sectional area converted into a circle,
(Calculated from a micrograph containing at least 100 columnar crystals in the visual field) is preferably about 1 to 50 μm, more preferably 1 to 30 μm.

The size of the gap between the columnar crystals was 30 μm.
The thickness is preferably 5 μm or less, more preferably 5 μm or less. That is,
If the gap exceeds 30 μm, scattering of laser light in the phosphor layer increases, and sharpness decreases.

The growth angle of the oblique columnar crystal of the stimulable phosphor is not particularly limited as long as it is larger than 0 ° and smaller than 90 °, but it is preferably 10 to 70 °, more preferably 20 to 55 °. is there. To make the growth angle 10-70 °, the incident angle is set to 20.
The incident angle may be set to 40 to 70 ° and the incident angle may be set to 40 to 70 °. If the growth angle is large, the columnar crystals will fall too much with respect to the support, and the film will become brittle.

As a method for vapor-phase growing (depositing) the stimulable phosphor, there are a vapor deposition method, a sputtering method and a CVD method.

[0083] deposition method, after installing a support in a vapor deposition apparatus, and evacuating the system as 1.333 × 10 ^-4 Pa vacuum of about, then at least one resistance of the stimulable phosphor The stimulable phosphor is obliquely deposited to a desired thickness on the surface of the support by heating and evaporating it by a method such as a heating method or an electron beam method. As a result, a stimulable phosphor layer containing no binder is formed, but the stimulable phosphor layer may be formed in a plurality of times in the vapor deposition step. Further, in the vapor deposition step, vapor deposition can be performed using a plurality of resistance heaters or electron beams. In the vapor deposition method, a stimulable phosphor material is vapor-deposited using a plurality of resistance heaters or electron beams to synthesize a desired stimulable phosphor on a support and simultaneously form a stimulable phosphor layer. It is also possible to form. Further, in the vapor deposition method, an object to be deposited may be cooled or heated as needed during the vapor deposition. After the deposition, the stimulable phosphor layer may be subjected to a heat treatment.

In the sputtering method, a support is placed in a sputtering apparatus in the same manner as the above-mentioned vapor deposition method, and then the inside of the apparatus is once evacuated to a degree of vacuum of about 1.333 × 10 ⁻⁴ Pa, and then used as a gas for sputtering. An inert gas such as Ar or Ne is introduced into the apparatus to have a gas pressure of about 1.333 × 10 ^-1 Pa. Next, using the stimulable phosphor as a target, the stimulable phosphor is obliquely deposited on the surface of the support to a desired thickness by sputtering obliquely. In this sputtering step, the stimulable phosphor layer can be formed in a plurality of times in the same manner as the vapor deposition method, or the stimulable phosphor layer can be formed by sputtering the target simultaneously or sequentially using each of them. It is also possible to form In the sputtering method, a plurality of stimulable phosphor materials can be used as a target, and these can be simultaneously or sequentially sputtered to form a desired stimulable phosphor layer on a support. If necessary, reactive sputtering may be performed by introducing a gas such as O ₂ or H ₂ . Further, in the sputtering method, the object to be deposited may be cooled or heated as required during the sputtering. Further, the stimulable phosphor layer may be subjected to a heat treatment after the end of the sputtering.

In the CVD method, a binder is contained on a support by decomposing an intended stimulable phosphor or an organometallic compound containing a stimulable phosphor raw material with energy such as heat or high-frequency power. It is possible to obtain a stimulable phosphor layer that does not have any specific stimulable phosphor layer, and to vapor-grow the stimulable phosphor layer into independent elongated columnar crystals with a specific inclination with respect to the normal direction of the support. .

The thickness of the stimulable phosphor layer formed by these methods varies depending on the sensitivity of the intended radiation image conversion panel to radiation, the type of stimulable phosphor, etc.
It is preferably selected from the range of 0 μm to 1000 μm, and more preferably selected from the range of 20 μm to 800 μm.

As the support used in the radiation image conversion panel of the present invention, various polymer materials, glass, metals and the like are used. For example, plate glass such as quartz, borosilicate glass, chemically strengthened glass, or cellulose is used. Acetate film, polyester film, polyethylene terephthalate film, polyamide film, polyimide film, triacetate film, plastic film such as polycarbonate film, aluminum,
A metal sheet of iron, copper, chromium or the like or a metal sheet having a coating layer of hydrophilic fine particles is preferable. 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 in advance 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 and the like of the support used, but is generally 80 μm to 2000 μm.
m, more preferably 8 from the viewpoint of handling.
It is 0 μm to 1000 μm.

The protective layer provided on the radiation image conversion panel having the coating type phosphor layer is ASTM D-1003.
The haze ratio measured by the method described in 5 above is 5% to 60%.
% Of a polyester film having an excitation light absorbing layer of less than
Polymethacrylate film, nitrocellulose film, cellulose acetate film, etc. can be used,
A stretched film such as a polyethylene terephthalate film or a polyethylene naphthalate film is preferably used as a protective layer in terms of transparency and strength, and furthermore, a metal oxide, silicon nitride, or the like on these polyethylene terephthalate films or polyethylene terephthalate films. A vapor-deposited film obtained by vapor-depositing a thin film such as the above is more preferable from the viewpoint of moisture-proof property.

The haze ratio of the film used in the protective layer can be easily adjusted by selecting the haze ratio of the resin film to be used, and a resin film having an arbitrary haze ratio can be easily obtained industrially. . It is assumed that the protective film of the radiation image conversion panel has a very high optical transparency. Various plastic films having a haze value in the range of 2 to 3% are commercially available as such a highly transparent protective film material. A preferable haze ratio for obtaining the effect of the present invention is 5%.
Not less than 60%, more preferably not less than 10% and 5%.
It is less than 0%. If the haze ratio is less than 5%, the effect of eliminating image unevenness and linear noise is low, and if it is 60% or more, the effect of improving sharpness is impaired, which is not preferable.

The film used in the protective layer according to the present invention includes:
According to the required moisture-proof properties, it is possible to obtain the optimum moisture-proof properties by laminating multiple layers of resin film or a metal film on the resin film. In consideration of prevention, the moisture permeability is preferably at least 5.0 g / m ² · day or less.
The method for laminating the resin film is not particularly limited, and any known method may be used.

The protective film may be in close contact with the stimulable phosphor layer via an adhesive layer, but is provided so as to cover the phosphor surface (hereinafter, also referred to as a sealing or sealing structure). Is more preferable. In sealing the phosphor sheet, any known method may be used.However, when the outermost resin layer on the side of the moisture-proof protective film in contact with the phosphor sheet is made of a heat-fusible resin film, the moisture-proof protective film cannot be sealed. This is one of the preferred embodiments in that the protective film can be fused and the sealing work of the phosphor sheet is made more efficient. Furthermore, a moisture-proof protective film is disposed above and below the phosphor sheet, and the peripheral edge thereof is located outside the peripheral edge of the phosphor sheet, and the upper and lower moisture-proof protective films are heated and fused with an impulse sealer or the like. The use of a sealing structure is preferable because it prevents moisture from entering from the outer peripheral portion of the phosphor sheet. Furthermore, by making the moisture-proof protective film on the support surface side a laminated moisture-proof film formed by laminating one or more aluminum films, the invasion of moisture can be reduced more reliably. It is also easy and preferable. In the method of heat-sealing with the impulse sealer, the heat-sealing under a reduced-pressure environment is more preferable in terms of preventing displacement of the phosphor sheet in the moisture-proof protective film and eliminating moisture in the atmosphere.

The heat-fusible outermost resin layer on the side of the moisture-proof protective film that contacts the phosphor surface and the phosphor surface may or may not be adhered. Here, the state of non-adhesion means that even if the phosphor surface and the moisture-proof protective film are microscopically in point contact, the phosphor surface and the moisture-proof protective film are optically and mechanically almost discontinuous. It can be treated as a body. In addition, the above-mentioned resin film having a heat-fusing property is a resin film that can be fused with a generally used impulse sealer. For example, an ethylene-vinyl acetate copolymer (EVA), a polypropylene (PP) film, a polyethylene ( PE) film, etc., but the present invention is not limited thereto.

A phosphor sheet having a stimulable phosphor layer coated on a support is cut into a predetermined size. Any general method can be used for cutting, but a cosmetic cutting machine, a punching machine, or the like is desirable in terms of workability and accuracy.

Further, as the protective layer provided on the radiation image conversion panel having the vapor-deposited phosphor layer, a protective layer having good translucency and capable of being formed into a sheet can be used. For example, sheet glass such as quartz, borosilicate glass, and chemically strengthened glass, and organic polymers such as polyethylene terephthalate (PET) and polyvinyl chloride can be used.

The protective layer of the present invention may be a single layer or a multilayer, and may be composed of two or more layers made of different materials. For example, a film in which two or more polymer films are combined can be used. Examples of a method for producing such a composite polymer film include methods such as dry lamination, extrusion lamination, and co-extrusion coating lamination. The combination of two or more protective layers is not limited to organic polymers, but may be glass sheets or an organic polymer. For example, as a method of combining a sheet glass and a polymer layer, there is a method in which a coating liquid for a protective layer is directly applied to the sheet glass to form, or a polymer protective layer formed separately in advance is bonded to the sheet glass. . The two or more protective layers may be in close contact with each other or may be separated from each other.

The thickness of the protective layer of the present invention is practically 10 μm.
m to 3 mm. In order to obtain good moisture resistance and impact resistance, the thickness of the protective layer is preferably 100 μm or more, especially when a protective layer of 500 μm or more is provided, a conversion panel excellent in durability and durability can be obtained, More preferred.

[0098] When a sheet glass is used as the protective layer, it is particularly preferable because of its extremely excellent moisture resistance.

The protective layer desirably exhibits a high transmittance in a wide wavelength range in order to transmit the stimulated excitation light and the stimulated emission efficiently, and the transmittance is preferably 80% or more. Examples include quartz glass and borosilicate glass. Borosilicate glass is 80% in the wavelength range of 330 nm to 2.6 μm
The above transmittance is exhibited, and quartz glass exhibits a high transmittance even at a shorter wavelength.

It is preferable to provide an anti-reflection layer such as MgF _{2 on} the surface of the protective layer, because it has the effects of efficiently transmitting the stimulating light and the stimulating light and reducing the sharpness. Although the refractive index of the protective layer is not particularly limited, many of practically used materials have a refractive index between 1.4 and 2.0.

In the present invention, the material of the protective layer is preferably plate glass. The following method is used as a means for containing a coloring material in the glass and coloring the glass to have a function of absorbing stimulating excitation light.

(1) A film colored with a coloring material (pigment or dye) is laminated on glass. As a method for producing a colored film, there is a method in which a layer containing a coloring material (pigment or dye) is formed by coating or the like on the surface of a plastic film or a plastic film into which a coloring material is kneaded.

A colored glass used as a protective layer can be obtained by a method in which the colored plastic film produced by such a method is uniformly adhered to the glass surface using an adhesive or the like.

As a coloring material used for coloring, a pigment or dye absorbing stimulating light is suitable.

(2) A method in which a layer containing a dye or pigment is provided on one side of the glass by coating.

This is a method of obtaining a colored glass by applying a pigment or dye dispersed or dissolved in a binder (such as water glass or an organic polymer such as polyvinyl butyral) having good adhesion directly to the glass.

(3) Next, there is a method in which the glass itself contains a dispersed pigment or colorant as a coloring material.

For example, at the time of manufacture, a coloring agent such as lead phosphate is mixed as a coloring material into glass to be colored. In this case, it is a condition that the coloring material has good thermal stability because it is mixed during glass production, and inorganic pigment-based heat-resistant pigments can be dispersed and used.

[0109]

The present invention will be illustrated below with reference to examples.
The present invention is not limited to these examples.

Example 1 << Preparation of Radiation Image Conversion Panel >> A radiation image conversion panel 1 having a vapor-deposited phosphor layer was prepared according to the method described below.
To 6 were prepared.

[Preparation of Supports 1 to 5] Supports 1 to 5 having the following characteristics were prepared.

(Support 1) Transparent crystallized glass having a thickness of 500 μm.

(Support 2) Ceramic glass having a thickness of 500 μm.

(Support 3) A colored layer A1 was provided on the surface of a transparent crystallized glass having a thickness of 500 μm by the following method.

<Colored Layer A1> Titanium oxide manufactured by Fruichi Chemical Co. and zirconium oxide manufactured by the company have an absorbance of 0.03 at 400 nm and an absorbance of 0.03 at 660 nm.
A film was formed on the surface of the support using a vapor deposition apparatus so as to obtain a value of 08.

Incidentally, the refractive index of the colored layer A1 was 2.3. (Support 4) In the production of the support 3, the material of the support was changed to 5
The support 4 was produced in the same manner except that the ceramic glass was changed to a thickness of 00 μm.

(Support 5) A colored layer A2 was provided on the surface of a transparent crystallized glass having a thickness of 500 μm by the following method.

<Coloring layer A2> Copper phthalocyanine (manufactured by Sanyo Dyeing Co., Ltd.) and Byron 630 (manufactured by Toyobo Co., Ltd.) are added to methyl ethyl ketone so that the paint viscosity becomes 20 mPa · s, and dispersed by a ball mill for 10 hours. Solution was prepared and 40 μm thick transparent crystallized glass was
Coating was performed using a doctor blade so that the absorbance at 0 nm was 0.004 and the absorbance at 660 nm was 0.01.

Incidentally, the refractive index of the colored layer A2 was 1.9. [Preparation of Phosphor Plate] (Preparation of Phosphor Plate 1)
After heating at 40 ° C. and introducing a nitrogen gas into the vacuum chamber to reduce the degree of vacuum to 10 ⁻¹ Pa, an alkali halide phosphor composed of CsBr: Eu is applied to the surface of the support using a known vapor deposition apparatus. 30 ° with respect to the normal direction of the support surface
At an angle of 3 mm, the distance between the support and the slit (evaporation source) was set to 60 cm using an aluminum slit, and vapor deposition was performed while transporting the support in a direction parallel to the support.
A phosphor layer having a columnar structure with a thickness of 00 μm was formed, and a phosphor plate 1 was produced.

As a result of measuring the refractive index of the phosphor layer produced as described above, it was 1.8.

(Preparation of Phosphor Plate 2) In the preparation of the phosphor plate 1, the alkali halide phosphor was replaced with R
A phosphor plate 2 was produced in the same manner except that the support was changed to bBr: Tl and the support 2 was used instead of the support 1.

The refractive index of the phosphor layer produced as described above was measured and found to be 1.7.

(Preparation of Phosphor Plate 3) In the preparation of the above-described phosphor plate 1, a phosphor layer was formed in the same manner using the support 3 in place of the support 1, and the phosphor layer was formed on the surface of the phosphor layer. A phosphor plate 3 was prepared by providing the following colored layer B1.

<Coloring layer B1> Copper phthalocyanine manufactured by Sanyo Dyestuffs Co., Ltd. and Byron 630 manufactured by Toyobo Co., Ltd. were added to methyl ethyl ketone so that the paint viscosity became 20 mPa · s, and dispersed by a ball mill for 10 hours. An agent coating solution was prepared and applied to the surface of the phosphor layer using a doctor blade so that the absorbance at 400 nm was 0.004 and the absorbance at 660 nm was 0.01.

The refractive index of the colored layer B1 was 1.9. (Preparation of Phosphor Plate 4) In the preparation of the above-described phosphor plate 2, a phosphor layer is formed in the same manner using the support 4 instead of the support 2, and then the above-mentioned coloring is applied to the surface of the phosphor layer. The phosphor plate 4 was prepared by providing the layer B1.

(Preparation of Phosphor Plate 5) In the preparation of the above-described phosphor plate 1, a phosphor layer was formed in the same manner using the support 5 instead of the support 1, and then the phosphor layer was formed on the surface of the phosphor layer. A phosphor plate 5 was prepared by providing the following colored layer B2.

<Colored Layer B2> Titanium oxide manufactured by Fruichi Chemical Co. and zirconium oxide manufactured by Furuichi Chemical Co. have an absorbance of 0.03 at 400 nm and an absorbance of 0.03 at 660 nm.
A film was formed on the surface of the phosphor layer using a vapor deposition apparatus so as to reach 08.

The refractive index of the colored layer B2 was 2.3. [Preparation of Radiation Image Conversion Panel] (Preparation of Radiation Image Conversion Panels 1 to 5)
5 was produced.

A spacer is provided on the side edge of the surface having the phosphor layer, between each phosphor plate and the glass used as the protective layer, so that the air layer as a low refractive index layer has a thickness of 100 μm. A protective layer made of transparent glass having a refractive index of 1.6 was provided. The spacer is made of glass ceramic, and the thickness is adjusted so that the stimulable phosphor layer and the low refractive index layer (air layer) between the support and the protective layer have a predetermined thickness. The side edges of the protective layer made of glass were bonded using an epoxy adhesive.

(Preparation of Radiation Image Conversion Panel 6) In the preparation of the above radiation image conversion panel, the phosphor plate 3
The material of the protective layer is made of transparent glass, and the refractive index is 2.
A radiation image conversion panel 6 was produced in the same manner except that the special glass No. 0 was used.

<< Evaluation of Radiation Image Conversion Panel >> The contrast, sharpness and brightness of each radiation image conversion panel produced as described above were evaluated according to the following methods.

(Evaluation of Contrast) For evaluation of contrast, a lead disk having a thickness of 2 mm was imprinted on each produced radiation image conversion panel, uniformly irradiated with X-rays having a tube voltage of 80 kVp, and then a phosphor layer was provided. From the surface side, it is scanned and excited by a semiconductor laser beam (690 nm), and stimulated emission emitted from each phosphor layer is received by a photodetector (photoelectron image tube with a spectral sensitivity of S-5) and the image is obtained. Do it by reading,
Further, the image was output using a laser writing film printer, and the degree of black and white contrast appearing on the lead disk portion and its peripheral portion of the image was visually evaluated according to the following criteria in five steps. Evaluation 3
The following were judged not to be practically suitable for diagnosis.

5: Peripheral edge of lead disk and brightness difference between black and white are clearly confirmed 4: Peripheral edge of lead disk is slightly blurred, but brightness difference between black and white is almost clearly recognized 3: Lead disk peripheral portion 2: The brightness difference between black and white is not clear. 2: The brightness difference between the lead disk and black and white is not clear, and the lead disk size is not reproduced. 1: The brightness difference between the shape of the lead disk and the brightness difference between black and white. Unclear and low whiteness at the center (Evaluation of Sharpness) Regarding sharpness, the modulation transfer function (M
TF) was evaluated.

After the CTF chart was attached to each radiation image conversion panel, X-rays of 80 kVp were irradiated at 10 mR (distance to the subject; 1.5 m), and then the semiconductor laser light (690 nm) was irradiated from the side having the phosphor layer. , The power on the panel was 40 mW), and the CTF chart was scanned and read with a semiconductor laser beam having a diameter of 100 μmφ. The values described in Table 1 are obtained by setting the MTF value of the radiation image conversion panel 1 at 0.5 lp / mm to 100 as a relative value for each panel.

(Evaluation of Luminance) Luminance was measured at a tube voltage of 80 for each radiation image conversion panel with or without forced deterioration processing.
After irradiation with kVp X-rays, the panel is excited by operating with a semiconductor laser beam (690 nm), and the photostimulated emission emitted from the phosphor layer is received by a photodetector (photoelectron image tube with a spectral luminance of S-5). The intensity of the radiation was measured, and the intensity was measured. This was defined as the luminance, which was expressed as a relative value with the luminance of the radiation image conversion panel 1 being 100.

Table 1 shows the evaluation results obtained as described above.

[0137]

[Table 1]

As is clear from Table 1, the radiation image conversion panel of the present invention in which any of the constitutions of claims 1 to 3 or a combination thereof is not reduced in luminance as compared with the comparative radiation image conversion panel. In addition, it can be seen that a clear radiation image having excellent contrast and sharpness can be obtained.

Example 2 << Preparation of Radiation Image Conversion Panel >> A radiation image conversion panel 1 having a coating type phosphor layer according to the method described below.
1 to 16 were produced.

[Preparation of Supports 6 to 9] Supports 6 to 9 having the following characteristics were prepared.

(Support 6) A 250 μm thick polyethylene terephthalate film containing carbon black (hereinafter abbreviated as black PET).

(Support 7) A colored layer A3 was provided on the surface of black PET having a thickness of 250 μm by the following method.

<Coloring layer A3> Copper phthalocyanine manufactured by Sanyo Dyestuffs Co., Ltd. and Byron 630 manufactured by Toyobo Co., Ltd. were added to methyl ethyl ketone so that the paint viscosity became 20 mPa · s, and dispersed by a ball mill for 10 hours. An agent coating solution was prepared and applied to the surface of the black PET using a doctor blade such that the absorbance at 400 nm was 0.03 and the absorbance at 660 nm was 0.08.

The refractive index of the colored layer A3 was 1.9. (Support 8) A colored layer A4 was provided on the surface of a 250-μm-thick black PET by the following method.

<Coloring layer A4> Copper phthalocyanine manufactured by Sanyo Dyestuffs Co., Ltd. and Byron 630 manufactured by Toyobo Co., Ltd. were added to methyl ethyl ketone so that the paint viscosity became 20 mPa · s, and dispersed by a ball mill for 10 hours. An agent coating solution was prepared and applied to the surface of the black PET using a doctor blade such that the absorbance at 400 nm was 0.02 and the absorbance at 660 nm was 0.05.

Incidentally, the refractive index of the colored layer A4 was 1.9. (Support 9) Colored layer A5 was provided on the surface of 250 μm thick black PET by the following method.

<Coloring layer A5> Copper phthalocyanine (manufactured by Sanyo Dyeing Co., Ltd.) and Byron 630 (manufactured by Toyobo Co., Ltd.) are added to methyl ethyl ketone so that the paint viscosity becomes 20 mPa · s, and dispersed by a ball mill for 10 hours. An agent coating solution was prepared and applied to the surface of the black PET using a doctor blade so that the absorbance at 400 nm was 0.01 and the absorbance at 660 nm was 0.03.

The refractive index of the colored layer A5 was 1.9. [Formation of Phosphor Layer] (Preparation of Phosphor Sheet 1) <Preparation of Phosphor> In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, a BaBr ₂ aqueous solution (3.6 mol) was used. / L) and 2 ml of EuBr ₃ aqueous solution (0.15 mol / L) were put into a reactor.
The reaction mother liquor in the reactor was kept at 83 ° C. while stirring. Next, an aqueous solution of ammonium fluoride (8 mol / L)
322 ml were injected into the reaction mother liquor using a roller pump to produce a precipitate. Keep warm and stir even after pouring
The sediment was aged continuously over time. Next, the precipitate was separated by filtration, washed with ethanol, and dried under vacuum to obtain europium-activated barium fluorobromide crystals. In order to prevent a change in particle shape due to sintering during firing and a change in particle size distribution due to inter-particle fusion, 0.2% by mass of ultrafine alumina powder is added, and the mixture is sufficiently stirred with a mixer to obtain a crystal surface. Alumina ultrafine particles were uniformly adhered to the substrate.
This was filled in a quartz boat, baked at 850 ° C. for 2 hours in a hydrogen gas atmosphere using a tube furnace, and then classified to prepare a europium-activated barium fluorobromide phosphor having an average particle size of 4 μm. did.

<Preparation of Phosphor Layer Coating Solution> 100 g of the phosphor prepared above and 16.7 g of a polyester resin having a Tg of 45 ° C. (solid content: 30%) were added to a mixed solvent of methyl ethyl ketone-toluene (1: 1). Then, the mixture was dispersed with a propeller mixer, and the viscosity was adjusted to 25 to 30 Pa · s to prepare a phosphor layer coating solution.

<Preparation of Phosphor Sheet> The phosphor layer coating solution prepared above was coated on the support 6 prepared above with a doctor blade so as to have a thickness of 160 μm. After drying for 15 minutes, the phosphor sheet 1 was produced.

The refractive index of the phosphor sheet 1 produced above is
1.9. (Preparation of Phosphor Sheet 2) In the preparation of the phosphor sheet 1, the europium-activated barium fluorobromide phosphor, which is a phosphor, is replaced with the europium-activated barium fluoroiodide phosphor prepared by the same method. Same except for the change,
A phosphor sheet 2 was produced.

(Preparation of Phosphor Sheet 3) In the preparation of the phosphor sheet 1, a phosphor layer was formed in the same manner using the support 7 instead of the support 6, and then the phosphor layer was coated on the surface of the phosphor layer. A phosphor sheet 3 was prepared by providing the following colored layer B3.

<Coloring layer B3> Copper phthalocyanine manufactured by Sanyo Dyestuffs Co., Ltd. and Byron 630 manufactured by Toyobo Co., Ltd. were added to methyl ethyl ketone so that the coating viscosity became 20 mPa · s, and dispersed by a ball mill for 10 hours. An agent coating solution was prepared and applied to the surface of the phosphor layer using a doctor blade such that the absorbance at 400 nm was 0.01 and the absorbance at 660 nm was 0.03.

The refractive index of the colored layer B3 was 1.9. (Preparation of Phosphor Sheet 4) A phosphor sheet 4 was prepared in the same manner as in the preparation of the phosphor sheet 3 except that the support 8 was used instead of the support 7.

(Preparation of Phosphor Sheet 5) In the preparation of the phosphor sheet 3, a europium-activated barium fluorobromide phosphor, which is a phosphor, was prepared in the same manner as that of europium-activated barium fluoroiodide. A phosphor sheet 5 was produced in the same manner except that the phosphor sheet was changed.

(Preparation of Phosphor Sheet 6) In the preparation of the phosphor sheet 1, a phosphor layer was formed in the same manner using the support 9 instead of the support 6, and then the phosphor layer was coated on the surface of the phosphor layer. The phosphor sheet 6 was prepared by providing the following colored layer B4.

<Coloring Layer B4> Copper phthalocyanine manufactured by Sanyo Dyeing Co., Ltd. and Byron 630 manufactured by Toyobo Co., Ltd. are added to methyl ethyl ketone so that the coating viscosity becomes 20 mPa · s, and dispersed by a ball mill for 10 hours. An agent coating solution was prepared and applied to the surface of the phosphor layer using a doctor blade such that the absorbance at 400 nm was 0.03 and the absorbance at 660 nm was 0.08.

The refractive index of the colored layer B4 was 1.9. [Preparation of Radiation Image Conversion Panel] (Preparation of Radiation Image Conversion Panels 11 to 16) Radiation image conversion panels 11 to 16 were prepared using the phosphor sheets 1 to 6 prepared above.

<Preparation of Protective Layer> A protective layer having the following structure (A) was used as a protective layer on the phosphor layer-coated surface of the phosphor sheets 1 to 6 prepared above.

Configuration (A) NY15 / VMPET12 / VMPET12 / PET1
2 / CPP20 NY: Nylon PET: Polyethylene terephthalate CPP: Casting polypropylene VMPET: Alumina-deposited PET (commercially available: manufactured by Toyo Metallizing Co.) .

The above “/” means that the dry lamination adhesive layer has a thickness of 3.0 μm. As the used adhesive for dry lamination, a two-component reaction type urethane-based adhesive was used.

The refractive index of the protective layer was 1.6. <Preparation of radiation image conversion panel> After cutting each of the prepared phosphor sheets 1 to 6 into a square having a side of 20 cm, using the above-prepared protective layer, the peripheral portion was fused using an impulse sealer. Radiation image conversion panels 11 to 16 which are sealed and provided with a low refractive index layer between the fluorescent layer and the protective layer
Was prepared. The fusion was performed so that the distance from the fusion portion to the peripheral edge of the phosphor sheet was 1 mm. The heater of the impulse sealer used for fusion had a width of 3 mm.

(Preparation of Radiation Image Conversion Panel 17) In the preparation of the above radiation image conversion panel, the phosphor sheet 3
A transparent PET film having a thickness of 12 μm, on which a polyester-based adhesive is applied on the phosphor layer, is disposed such that the adhesive surface overlaps the surface having the colored layer.
The radiation image conversion panel 17 having a non-sealing structure and no low refractive index layer is compressed under pressure using a heat roll of 00 ° C.
Was prepared.

<< Evaluation of Radiation Image Conversion Panel >> Each of the radiation image conversion panels produced as described above was evaluated for contrast, sharpness, and brightness in the same manner as described in Example 1, and obtained. The results are shown in Table 2.

[0165]

[Table 2]

As is clear from Table 2, the radiation image conversion panel of the present invention in which any of the constitutions of claims 1 to 3 or a combination thereof is not reduced in luminance compared with the comparative radiation image conversion panel. In addition, it can be seen that a clear radiation image having excellent contrast and sharpness can be obtained.

[0167]

According to the present invention, sharpness, contrast,
A radiation image conversion panel with excellent brightness was provided.

Claims (3)

[Claims] 1. A radiation image conversion panel comprising: a phosphor sheet provided with a phosphor layer containing a stimulable phosphor on a support; and a protective layer provided so as to cover the phosphor sheet. A colored layer A is provided between the support and the phosphor layer, and a colored layer B is provided between the phosphor layer and the protective layer, and the absorbance of the colored layer A is higher than the absorbance of the colored layer B. A radiation image conversion panel characterized by the above-mentioned. 2. The spectral absorption characteristics of the colored layer A and the colored layer B are each higher in absorbance on the long wavelength side (600-700 nm) than on the short wavelength side (370-500 nm). 2. The radiation image conversion panel according to 1. 3. A radiographic image comprising a phosphor sheet having a phosphor layer containing a stimulable phosphor on a support, and a low refractive index layer and a protective layer provided so as to cover the phosphor sheet. In the conversion panel, a coloring layer A is provided between the support and the phosphor layer, and a coloring layer B is provided between the phosphor layer and the protective layer. A radiation image conversion panel, wherein the refractive index of the protective layer and the low refractive index layer and the refractive index of the phosphor layer are represented by the following formula 1. Formula 1 Refractive index of protective layer and low refractive index layer ≦ Refractive index of phosphor layer ≦ Refractive index of colored layer A and colored layer B