JP2001056399A - Radiation image conversion panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a radiation image conversion panel obtainable of high grade image by reducing image nose of the radiation image conversion panel having duplicate fluorescent layers. SOLUTION: In a radiation image conversion panel consisting of at least a support body 11 and a fluorescent layer 14 layering fluorescent sheets 12 and 13, the fluorescent layer 14 is duplication of separative surfaces 12a and 13a of fluorescent body sheets 12 and 13 obtained by separating from a tentative support body and the average value of 85 degree glossiness of the separative surfaces 12a and 13a of the fluorescent sheet is made 56 or more.

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 utilizing the stimulable properties of a stimulable phosphor, and more particularly to a radiation image conversion panel in which phosphor sheets are stacked.

[0002]

2. Description of the Related Art As an alternative to conventional radiography,
For example, a radiation image conversion method using a stimulable phosphor as described in JP-A-55-12145 is known. This method uses a radiation image conversion panel (also referred to as a stimulable phosphor sheet) containing a stimulable phosphor, and emits radiation transmitted through a subject or emitted from a subject to the stimulable phosphor. The radiation energy stored in the stimulable phosphor is absorbed by the phosphor, and then the stimulable phosphor is excited by electromagnetic waves (excitation light) such as visible light and infrared light in a time series manner. This is emitted as fluorescence (stimulated emission light), the fluorescence is read photoelectrically to obtain an electric signal, and a radiation image of a subject or a subject is reproduced as a visible image based on the obtained electric signal.

According to this radiographic image conversion method, a radiographic image with a large amount of information can be obtained with a much smaller exposure dose than the radiographic method using a combination of a conventional radiographic film and an intensifying screen. There is an advantage that it can be obtained. Therefore, this method is very useful especially in direct medical radiography at the time of X-ray radiography for medical diagnosis.

The radiation image conversion panel used in the radiation image conversion method does not necessarily require a support when the phosphor layer is self-supporting, but otherwise, as a basic structure, a support and its support It consists of a stimulable phosphor layer provided on one side. Further, a transparent protective film is usually provided on the surface of the stimulable phosphor layer opposite to the support (the surface not facing the support) so that the phosphor layer is chemically coated. Protects against alteration or physical impact.

[0005] The stimulable phosphor layer generally comprises a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state. The stimulable phosphor absorbs radiation such as X-rays and then absorbs the radiation. It has the property of exhibiting stimulated emission when irradiated with excitation light. Therefore, the radiation transmitted through the subject or emitted from the subject is absorbed by the stimulable phosphor layer of the radiation image conversion panel in proportion to the radiation dose, and the radiation image of the subject or the subject is applied to the panel. It is formed as an energy storage image. This accumulated image can be emitted as stimulated emission light by irradiating the excitation light, and the accumulated image of radiation energy is imaged by photoelectrically reading the stimulated emission light and converting it into an electric signal. It is possible to do.

Although the radiation image conversion method is a very advantageous image forming method as described above, the radiation image conversion panel used in this method has the same high sensitivity as the intensifying screen used in conventional radiography. Further, it is desired to provide a good image quality (sharpness, granularity, etc.).

Conventionally, photostimulated light was read only from the surface of the radiation image conversion panel and converted into an electric signal.
Recently, reading has been performed from both the front and back surfaces of the radiation image conversion panel, and the read data on the back surface has been electrically added to the read data on the front surface. It was found that image information could be obtained.

The phosphor layer of the radiation image conversion panel used for double-sided reading has a single-layered phosphor layer unlike the phosphor layer of the conventional radiation image conversion panel used for single-sided reading. A so-called multilayer phosphor layer in which the release surfaces of a phosphor sheet obtained by coating and drying on a temporary support having a release layer are preferable. This is because, in a radiation image conversion panel having a multilayer phosphor layer in which the release surfaces are bonded to each other, the distribution of the phosphor in the thickness direction from the front side and the back side of the phosphor layer is almost uniformly dispersed. This is because the image quality when the data from the front side and the data from the back side of the radiation image conversion panel are added is high.

[0009]

In a radiation image conversion panel used for double-sided reading, the influence of the degree of dispersion of the phosphor is likely to appear even with a single layer, but especially in the case of a panel having a multi-layer phosphor layer, the back side is read. The influence of the degree of dispersion of the phosphor appears remarkably in the data. Although the reason for this is not clear, it is conceivable that a slight change in unevenness on the release surface side of the phosphor layer may appear as image noise in double-sided reading.

The radiation image conversion panel having the multilayer phosphor layer has a high image quality as described above when the irradiation X-ray amount is small, but when the irradiation X-ray amount is large, noise is conspicuous in the image. However, there is a problem that tends to be low.

The present invention has been made in view of the above circumstances, and in a radiation image conversion panel having a multilayer phosphor layer, the influence of the degree of dispersion of the phosphor is unlikely to appear as image noise, and the radiation X-ray amount is large. It is another object of the present invention to provide a radiation image conversion panel capable of obtaining a high-quality radiation image with less image unevenness.

[0012]

The radiation image conversion panel of the present invention is a radiation image conversion panel comprising at least a support and a phosphor layer obtained by laminating a plurality of phosphor sheets on the support. Wherein the release layer of the phosphor sheet obtained by releasing the phosphor layer from the temporary support is overlapped with each other, and the release surface of the phosphor sheet is 85
The average glossiness is 56 or more.

When the average value of the 85-degree glossiness of the release surface of the phosphor sheet is 56 or more, the phosphor sheet surface which was in contact with the temporary support when the phosphor sheet was released from the temporary support. Means that the average value of the glossiness obtained by measuring the 85-degree specular glossiness specified in JIS-8142 or ISO-2813 is 56 or more. Note that the glossiness means the glossiness of the phosphor sheet in an untreated state peeled from the temporary support, for example, in a state before subjected to a heat compression treatment or the like.

The release surfaces are superimposed on each other, and the average value of the 85-degree glossiness of the release surfaces of the superposed phosphor sheets is preferably 56 or more, more preferably 58 or more. .

[0015] The phosphor layer obtained by releasing the phosphor sheet from the temporary support in such a manner that the release surfaces of the phosphor sheet are overlapped with each other means that, for example, the phosphor layer is formed of two phosphor sheets. Means that the two phosphor sheets are obtained by overlapping their release surfaces when released from the temporary support, and in the case of three phosphor sheets, It means that the release surfaces of at least two phosphor sheets released from the temporary support are overlapped with each other.

The radiation image conversion panel can be used for double-sided condensing reading in which reading is performed from both the front and back surfaces of the panel.

[0017]

According to the radiation image conversion panel of the present invention, there is provided a radiation image conversion panel comprising at least a support and a phosphor layer obtained by laminating a plurality of phosphor sheets on the support. The release sheet of the phosphor sheet obtained by releasing the layer from the temporary support is obtained by superimposing the release surfaces on each other, and the average value of the 85-degree glossiness of the release surface of the phosphor sheet is 56 As described above, the release surface side of the phosphor sheet becomes a smooth surface, and a radiation image conversion panel with less image noise can be obtained.

In particular, conventionally, in a radiation image conversion panel having a so-called multilayer phosphor layer in which a plurality of phosphor sheets are laminated, if the irradiation X-ray amount is large, noise is conspicuous in the image, and the image quality tends to be low. However, by making the release surface of the phosphor sheet a smooth surface, image noise is reduced,
The image quality can be improved.

In general, when a radiation image conversion panel having a multi-layer phosphor layer is used for double-sided condensing reading, the influence of the degree of dispersion of the phosphor appears remarkably on the back side reading data. Is used for double-sided condensing reading, since the average value of the 85-degree glossiness of the release surface of the phosphor sheet is set to 56 or more, the release surface side of the phosphor sheet becomes a smooth surface, It is possible to effectively suppress image noise that is considered to be caused by subtle unevenness of the mold surface.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
First, the phosphor used in the present invention will be described.
The stimulable phosphor is a phosphor that emits stimulable light when irradiated with radiation and then irradiated with excitation light as described above, but the wavelength is in the range of 400 to 900 nm from a practical viewpoint. It is desirable that the phosphor be a phosphor that shows stimulated emission in a wavelength range of 300 to 500 nm by the excitation light. Examples of the stimulable phosphor used in the radiation image conversion panel of the present invention are disclosed in
BaSO are described in EP 80487 _4: AX and JP 48-804
SrSO is described in JP 89 _4: phosphor represented by AX, JP 53-39277 Li ₂ B ₄ O is described in JP _7: Cu, Ag, JP
Li ₂ O · (B ₂ O ₂ ) x: Cu described in No. 54-47883 and
_{Li 2 O · (B2O2) x} : Cu, Ag, are described in U.S. Pat. No. 3,859,527 SrS: Ce, Sm, SrS : Eu, Sm, ThO 2: Er, and La ₂ O ₂ S: Eu , Sm, Z described in JP-A-55-12142.
nS: Cu, Pb, BaO.xAl ₂ O ₃ : Eu (0.8 ≦ x ≦ 10),
And M ^II O.xSiO ₂ : A (where M ^II is Mg, Ca, Sr, Z
n, Cd, or Ba, and A is Ce, Tb, Eu, Tm, Pb, T
l, Bi, or Mn, and x satisfies 0.5 ≦ x ≦ 2.5), and is described in JP-A-55-12143 (Ba _1-Xy , M
g _X , Ca _y ) FX: aEu ²⁺ (where X is at least one of Cl and Br, and x and y are 0 <x + y ≦ 0.
6, and xy ≠ 0, a is 10 ⁻⁶ ≦ a ≦ 5 × 10 ⁻² ) and LnOX: xA described in JP-A-55-12144 (where Ln is La, Y , Gd, and Lu, X is at least one of Cl and Br, A is at least one of Ce and Tb, and x is 0 <x
<0.1), described in JP-A-55-12145 (Ba1 _-X , M2 ⁺ X) FX: yA (where M2 ⁺ is Mg, Ca, Sr, Zn,
And X is at least one of Cl, Br, and I, A is Eu, Tb, Ce, Tm, Dy,
At least one of Pr, Ho, Nd, Yb, and Er, and x is 0 ≦ x ≦ 0.6, and y is 0 ≦ y ≦ 0.2),
BaFX are described in JP 55-843897: represented by xCe · yA described in the phosphor JP 55-160078 M ^II F
X · xA: yLn (However, M ^II is Ba, Ca, Sr, Mg, Zn, and
At least one of Cd, A is BeO, MgO, CaO, SrO,
_{BaO, ZnO, Al 2 O 3} , Y 2 O 3, La 2 O 3, In 2 O 3, SiO 2, TiO 2, Z
at least one of rO ₂ , GeO ₂ , SnO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , and ThO ₂ , Ln is Eu, Tb, Ce, Tm, Dy, Pr, Ho, N
at least one of d, Yb, Er, Sm, and Gd, X
Is at least one of Cl, Br, and I, and x
And y are respectively 5 × 10 ⁻⁵ ≦ x ≦ 0.5, and 0 <y
.Ltoreq.0.2).
(Ba _1-X , M ^II _X ) F ₂ · aBaX ₂ described in −116777:
yEu, zA (where M ^II is at least one of beryllium, magnesium, calcium, strontium, zinc, and cadmium, X is at least one of chlorine, bromine, and iodine, and A is at least one of zirconium and scandium. A, x, y,
And z are respectively 0.5 ≦ a ≦ 1.25, 0 ≦ x ≦ 1, 10 ⁻⁶
≦ y ≦ 2 × 10 ⁻¹ and 0 <z ≦ 10 ⁻² ) phosphors described in JP-A-57-23673 (Ba _1-X , M ^II _X). ) F ₂ · aBaX ₂ : yEu, zB (where M ^II is at least one of beryllium, magnesium, calcium, strontium, zinc, and cadmium,
X is at least one of chlorine, bromine, and iodine, and a, x, y, and z are each 0.5 ≦ a ≦ 1.2.
5, 0 ≦ x ≦ 1, 10 ⁻⁶ ≦ y ≦ 2 × 10 ⁻¹ , and 0 <z ≦ 1
Phosphor represented by a composition formula of 0 ^-2 it is), JP-57-2
No. 3675 (Ba _1-X , M ^II _X ) F ₂ · aBaX ₂ : yEu,
zA (where M ^II is at least one of beryllium, magnesium, calcium, strontium, zinc, and cadmium, X is at least one of chlorine, bromine, and iodine, and A is at least one of arsenic and silicon. A, x, y, and z are each 0.
5 ≦ a ≦ 1.25, 0 ≦ x ≦ 1, 10 ⁻⁶ ≦ y ≦ 2 × 10 ⁻¹ , and 0 <z ≦ 5 × 10 ⁻¹ ). M ^III OX has been described in JP -69281: xCe
(However, M ^III is Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, E
at least one trivalent metal selected from the group consisting of r, Tm, Yb, and Bi, X is any one or both of Cl and Br, and x is 0 <x <0.1) A phosphor represented by the following composition formula:
Ba _1-X M _{X / 2} L _{X / 2} FX: yEu ²⁺
M represents at least one alkali metal selected from the group consisting of Li, Na, K, Rb, and Cs; L represents Sc,
Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, T
m represents at least one trivalent metal selected from the group consisting of Lu, Al, Ga, In, and Tl; X represents Cl, B
r represents at least one halogen selected from the group consisting of r and I; and x is 10 ⁻² ≦ x ≦ 0.5, and y is 0 <y ≦ 0.1. BaFX.xA: yEu ²⁺ described in JP-A-59-27980 (where X is at least one halogen selected from the group consisting of Cl, Br and I; A is a tetrafluoroborate compound) And x is 10 ⁻⁶ ≦ x
≦ 0.1, y is 0 <phosphor represented by a composition formula of y ≦ a 0.1), xM ₃ as described in JP-A-59-38278 (P
O ₄ ) ₂・ NX ₂ : yA, M ₃ (PO ₄ ) ₂ : yA and nReX _{3 ・} mAX ′ ₂ : xE
u, nReX ₃・ mAX ′ ₂ : xEu, ySm, M ^I X ・ aM ^II X ′ ₂・ bM
^III X ″ ₃ : a phosphor represented by ₃ : cA, BaFX.xA: yEu ²⁺ described in JP-A-59-47289 (where X is Cl, Br,
And A is selected from the group consisting of hexafluorosilicic acid, hexafluorotitanic acid and a salt of a monovalent or divalent metal of hexafluorozirconic acid. A phosphor of at least one compound; x is 10 ^-6 ≤ x ≤ 0.1, and y is 0 <y ≤ 0.1), which is described in JP-A-59-56479. BaFX · xNaX ′: aEu ²⁺ (where X and X ′ are at least one of Cl, Br and I, respectively, and x and a are respectively 0 <x ≦ 2 and 0 <a ≦ 0.2) a phosphor represented by a composition formula:
M ^II FXxNaX ': yEu described in JP-A-59-56480
²⁺ : zA (where MII is at least one alkaline earth metal selected from the group consisting of Ba, Sr, and Ca;
X and X 'are each at least one halogen selected from the group consisting of Cl, Br, and I;
At least one fiber metal selected from V, Cr, Mn, Fe, Co, and Ni; and x is 0 <x ≦ 2, y is 0 <y ≦ 0.2, and z is 0 <z ≦ 10 ^−. phosphor represented by a composition formula of ^{2. it), M II FX · aM I} X '· bM' II X that are described in ^{_{JP-a-59-75200 "2 · cM III X 3}} · xA: yEu 2 ⁺
(Where M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr, and Ca; M ^I is L
i, Na, K, is at least one alkali metal Rb, and selected from the group consisting of Cs; M ^'II is Be and Mg
X is at least one divalent metal selected from the group consisting of; M ^III is at least one trivalent metal selected from the group consisting of Al, Ga, In, and Tl; A is a metal oxide; Is at least one halogen selected from the group consisting of Cl, Br, and I; X ', X ", and X
Is at least one halogen selected from the group consisting of F, Cl, Br, and I; and a is 0 ≦ a ≦
2, b is 0 ≦ b ≦ 10 ⁻² , c is 0 ≦ c ≦ 10 ⁻² , and a + b
+ C ≧ 10 ⁻⁶ ; x is 0 <x ≦ 0.5, y is 0 <y ≦ 0.2
A phosphor represented by a composition formula of JP-A-60-8438.
M ^II X ₂・ aM ^II X ′ ₂ : xEu ²⁺ described in No. 1 (However,
M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; X and X ′ are Cl, B
at least one halogen selected from the group consisting of r and I, and X ≠ X ′; and a is 0.1
≦ a ≦ 10.0, x is 0 <x ≦ 0.2), a stimulable phosphor represented by the composition formula: M ^II FX · aM ^I X ′: xEu ² described in JP-A-60-101173. ⁺ (However, M ^II is Ba, Sr and
M is at least one alkali earth metal selected from the group consisting of Ca; M ^I is at least one alkali metal selected from the group consisting of Rb and Cs; X is selected from the group consisting of Cl, Br and I X 'is at least one halogen selected from the group consisting of F, Cl, Br and I; and a and x are 0≤a≤4.0 and 0 <x≤0.2, respectively. stimulable phosphor represented by the composition formula, M ^I X are described in JP-a-62-25189: xBi (However, 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 0 <x ≦ 0.2
And a stimulable phosphor represented by the composition formula:

Further, the JP 60-84381 No. M ^II X ₂ · aM ^II X described in the _'2: xEu ²⁺ stimulable phosphor, additives such as shown below M ^II X ₂ · aM ^II X ′ ₂ may be contained in the following ratio per 1 mol.

BM described in JP-A-60-166379
^I X "(although, M ^I is at least one alkali metal selected from the group consisting of Rb and Cs, X" is F, Cl,
At least one halogen selected from the group consisting of Br and I, and b is 0 <b ≦ 10.0); bKX ″ · cMgX ₂ · dM described in JP-A-60-221483.
^III X ′ ₃ (where M ^III is at least one trivalent metal selected from the group consisting of Sc, Y, La, Gd and Lu;
X ″, X and X ′ are at least one halogen selected from the group consisting of F, Cl, Br and I;
And b, c and d are respectively 0 ≦ b ≦ 2.0, 0 ≦
c ≦ 2.0, 0 ≦ d ≦ 2.0, and 2 × 10 ⁻⁵ ≦ b + c
+ D); yB described in JP-A-60-228592.
(However, y is 2 × 10 ⁻⁴ ≦ y ≦ 2 × 10 ⁻¹ ); bA described in JP-A-60-228593 (where A is SiO ₂
And at least one oxide selected from the group consisting of P ₂ O ₅ and b is 10 ⁻⁴ ≦ b ≦ 2 × 10 ⁻¹ );
BSiO described in JP-A-61-120883 (provided that b
Is 0 <b ≦ 3 × 10 ⁻² ); bSnX ″ ₂ (where X ″ is at least one member selected from the group consisting of F, Cl, Br and I) described in JP-A-61-120885. And b is <b ≦ 10 ^-3 ); JP-A-61-23.
BCsX ″ .cSnX ₂ described in No. 5486 (where X ″
And X are each at least one halogen selected from the group consisting of F, Cl, Br and I, and b and c are respectively 0 <b ≦ 10.0 and 10 ⁻⁶ ≦ c ≦ 2 ×
10 ^-2); and JP bCsX is described in JP 61-235487 "· yLn ³⁺ (However, X" is F, Cl, at least one halogen selected from the group consisting of Br and I Yes, Ln is Sc, Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho,
At least one rare earth element selected from the group consisting of Er, Tm, Yb and Lu, and b and y are respectively 0 <b ≦ 10.0 and 10 ⁻⁶ ≦ y ≦ 1.8 × 10 ⁻¹ ).

Among the above stimulable phosphors, a divalent europium-activated alkaline earth metal halide-based phosphor and a cerium-activated rare earth oxyhalide-based phosphor are particularly preferable because they exhibit high-luminance stimulable emission. However, the stimulable phosphor used in the present invention is not limited to the above-described phosphors, and any phosphor can be used as long as it exhibits stimulable emission when irradiated with radiation and then irradiated with excitation light. There may be.

As the binder used in the present invention, a thermoplastic elastomer which has elasticity at room temperature and becomes fluid when heated is suitably used. Examples of the thermoplastic elastomer include polystyrene, polyolefin, polyurethane, polyester, polyamide, polybutadiene, ethylene vinyl acetate, polyvinyl chloride, natural rubber, fluorine rubber, polyisoprene, chlorinated polyethylene, styrene-butadiene rubber, and silicone rubber. Can be mentioned.

Of the above-mentioned thermoplastic elastomers, those having a softening temperature or a melting point of 30 ° C. to 300 ° C. are generally used, and those having a softening temperature or a melting point of 30 ° C. to 200 ° C. are preferred.
It is more preferable to use one having a temperature of ° C.

The above binder is sufficiently mixed with a phosphor and a solvent to prepare a coating solution in which the stimulable phosphor is uniformly dispersed in the binder solution. Examples of the solvent include lower alcohols such as methanol, ethanol, propanol and butanol; hydrocarbons containing a chlorine atom such as methylene chloride and ethylene chloride; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; methyl acetate, ethyl acetate and butyl acetate Esters of lower fatty acids with lower alcohols such as dioxane, ethylene glycol monoethyl ether and ethylene glycol monomethyl ether; and mixtures thereof.

The mixing ratio between the binder and the stimulable phosphor in the coating solution varies depending on the intended characteristics of the radiation image conversion panel, the type of the phosphor, and the like. Is selected from the range of 1: 1 to 1: 100 (weight ratio), and is particularly preferably selected from the range of 1: 8 to 1:40 (weight ratio).

The coating solution contains a dispersant for improving the dispersibility of the phosphor in the coating solution, and also enhances the binding force between the binder and the phosphor in the formed phosphor layer. Various additives such as a plasticizer 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 phosphate esters such as triphenyl phosphate, tricresyl phosphate, and diphenyl phosphate; phthalate esters such as diethyl phthalate and dimethoxyethyl phthalate; ethyl phthalylethyl glycolate, and butyl glycolate Glycolic acid esters such as phthalylbutyl; 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.

The coating solution containing the phosphor and the binder prepared as described above is then uniformly applied to the surface of a temporary support for sheet formation to form a coating film of the coating solution. I do. This coating operation is performed by a normal coating means, for example,
It can be performed by using a doctor blade, a roll coater, a knife coater or the like.

The temporary support is, for example, glass, a metal plate,
Alternatively, it can be arbitrarily selected from various materials used as a support for an intensifying screen (or an intensifying screen) in a conventional radiographic method or a material known as a support for a radiation image conversion panel. Examples of such materials include cellulose acetate, polyester, polyethylene terephthalate, polyamide, polyimide,
Films of plastic materials such as triacetate and polycarbonate, metal sheets such as aluminum foil and aluminum alloy foil, ordinary paper, baryta paper, resin coated paper, pigmented paper containing pigments such as titanium dioxide, paper sized with polyvinyl alcohol, etc. And plates or sheets of ceramics such as alumina, zirconia, magnesia and titania.

The configuration of the radiation image conversion panel of the present invention will be described with reference to FIGS. 1 and 2, taking an example in which two phosphor sheets are laminated. As shown in FIG. 2, the radiation image conversion panel according to the present invention includes a phosphor sheet 1 on a support 11.
2 and a phosphor sheet 13 are laminated. The phosphor sheets 12 and 13 are provided on the temporary support 1 as shown in FIG.
The release surfaces 12a and 13a of the phosphor sheets 12 and 13 obtained by releasing from the base material 0 are superimposed on each other, and
It is laminated on top. 85 of the release surfaces 12a and 13a
The average value of the glossiness can be set to 56 or more by, for example, dispersing the phosphor layer forming coating liquid more sufficiently than the conventional phosphor layer for one-sided reading is prepared.

Next, the steps in the method for manufacturing a radiation image storage panel of the present invention will be described. Here, for the sake of simplicity, a radiation image conversion panel having a phosphor layer in which two phosphor sheets are stacked will be described. However, even if the number of phosphor sheets to be laminated is increased, the same can be manufactured.

First, a coating solution for forming a phosphor layer is applied on the temporary support 10 and dried, and then the phosphor sheets 12 and 13 are peeled off from the temporary support 10 to obtain the phosphor layer of the radiation image conversion panel. Are prepared. Therefore, it is preferable that a release agent is applied to the surface of the temporary support 10 in advance so that the formed phosphor sheets 12 and 13 can be easily peeled off from the temporary support. Phosphor sheets 12 and 13 formed as described above
Separately, a support 11 of the radiation image conversion panel is prepared. The support 11 can be arbitrarily selected from the same materials as the temporary support used when forming the phosphor sheet.

In a known radiation image conversion panel, the phosphor layer is used to strengthen the bond between the support and the phosphor layer or to improve the sensitivity or image quality (sharpness, granularity) of the radiation image conversion panel. A polymer material such as gelatin is applied to the surface of the support on which the surface is provided to form an adhesion-imparting layer, or a light-reflective layer made of a light-reflective material such as titanium dioxide, or a light-absorbing material such as carbon black It is known to provide a light absorbing layer made of The support used in the present invention can also be provided with these various layers, and the configuration thereof can be arbitrarily selected depending on the desired purpose and application of the radiation image storage panel.

Further, as described in JP-A-59-200200, the surface of the support on the side of the phosphor layer (the surface of the support on the side of the phosphor layer) is intended to improve the sharpness of the obtained image. When an adhesiveness-imparting layer, a light-reflecting layer, a light-absorbing layer, or the like is provided on the surface, it means the surface), and fine irregularities may be formed on the surface.

The phosphor sheet obtained by the dispersion coating is placed on a support, and is adhered to the support while being compressed at a temperature not lower than the softening temperature or the melting point of the binder.

Examples of the compression apparatus used for the compression processing of the present invention include generally known apparatuses such as a calender roll and a hot press. For example, the compression treatment using a calender roll is performed by placing a phosphor sheet obtained by dispersion coating on a support and passing the phosphor sheet at a constant speed between rollers heated to a temperature higher than the softening temperature or melting point of the binder. . However, the compression device used in the present invention is not limited to these devices, and may be any device capable of compressing the above-mentioned sheet while heating it. The pressure at the time of compression is generally 50 kgw / cm ² or more.

In a normal radiation image conversion panel, as described above, a transparent protective layer for physically and chemically protecting the phosphor layer is provided on the surface of the phosphor layer opposite to the side in contact with the support. A membrane is provided. Such a transparent protective film is preferably provided also for the radiation image conversion panel according to the present invention.

The transparent protective film is made of, for example, cellulose derivatives such as cellulose acetate and nitrocellulose; or polymethyl methacrylate, polyvinyl butyral,
A method of applying a solution prepared by dissolving a transparent polymer substance such as a synthetic polymer substance such as polyvinyl formal, polycarbonate, polyvinyl acetate, and vinyl chloride / vinyl acetate copolymer in a suitable solvent to the surface of the phosphor layer. Can be formed. Alternatively, a plastic sheet made of polyethylene terephthalate, polyethylene naphthalate, polyethylene, polyvinylidene chloride, polyamide, and the like; and a protective film forming sheet such as a transparent glass plate are separately formed, and an appropriate adhesive is applied to the surface of the phosphor layer. It can also be formed by a method such as bonding by using.

The thickness of the protective film is generally in the range of about 0.1 to 20 μm.

Further, for the purpose of improving the sharpness of the obtained image, at least one of the above layers may be provided with a colored layer which absorbs excitation light and does not absorb stimulated emission light. No. 59-23400). Next, examples of the present invention will be described. However, these embodiments do not limit the present invention.

(Example) Phosphor: A tetrahedral phosphor (BaFBr _0.85 I) was used as a coating solution for forming a phosphor sheet.
_0.15 : Eu ²⁺ ) 1000 g, binder 246 g (polyurethane elastomer; Dainippon Ink & Chemicals, Inc., Pandex T-5265H (solid)) dissolved in methyl ethyl ketone to a solid content concentration of 13 wt%), 3 g of a crosslinking agent (polyisocyanate; Nippon Polyurethane Industry Co., Ltd., Coronate HX (solid content: 100%)), 15 g of an anti-yellowing agent (epoxy resin; Yuka Shell Epoxy Co., Epicoat # 1001 (solid)) Solvent In addition to 69 g of methyl ethyl ketone, 2
Five kinds of coating liquids respectively dispersed at 400 rpm for 1, 2, 3, 4, 5 hours were prepared (weight ratio of binder / phosphor = 1).
/ 20) to give a coating solution of 30 ps. This coating solution is
A doctor blade is applied on a polyethylene terephthalate sheet (temporary support, thickness: 190 μm) to which a silicone-based release agent has been applied, dried, and peeled off from the temporary support to obtain five types of phosphor sheets (sheet thicknesses). : 200μ
m, application width = 300 mm).

The glossiness of the release surface is measured by using a VG-2000 gloss meter manufactured by Nippon Denshoku Industries Co., Ltd. as a measuring instrument, and measuring 85-degree specular gloss (a gloss measurement method according to ISO-2813 and JIS-P8142). It depends. Table 1 shows the results.

Next, a support was prepared. Byron 30
0 (unsaturated polyester resin; manufactured by Toyobo Co., Ltd.)
FS to 100 g of liquid (solid content = 15 wt%) dissolved in K
56.4 g of -10P MEK dispersion (SnO ₂ (Sb-doped) needle-shaped fine particles manufactured by Ishihara Sangyo Co., Ltd. (major axis = 0.2 to
2 μm, short axis = 0.01 to 0.02 μm); solid content = 3
0 wt%) and 48 g of methyl ethyl ketone were added to prepare a liquid having a viscosity of about 0.2 to 0.3 ps, which was used as a support (polyethylene terephthalate sheet (Lumirror S-10, manufactured by Toray Industries, Inc., 250 μm); haze degree (typica)
l) = 27) was applied so as to have a thickness of 3 μm. Further, on the surface opposite to the undercoat layer side of the support sheet, 92.5 g of a fluororesin (fluoroolefin = vinyl ether copolymer; Asahi Glass Co., Ltd., Lumiflon LF-504)
X (30% xylene solution)), cross-linking agent 5 g (polyisocyanate; Sumitomo Bayer Urethane Co., Ltd., Sumidur N3500 (solid content 100%)), slip agent 0.5 g (alcohol-modified silicone; Shin-Etsu Chemical Co., Ltd.) X-22
2809 (paste containing 66% xylene)), 6.5 g of organic filler (melamine-formaldehyde; Nippon Shokubai Co., Ltd., Eposter S6), 0.1 g of coupling agent
(Acetoalkoxyaluminum diisopropylate;
(Ajinomoto Co., Inc., Prenact AL-M), catalyst 0.35
mg (dibutyltin dilaurate; Kyodo Yakuhin, K)
S1260) was added to 66.5 g of methyl ethyl ketone, and the mixture was prepared in the same manner as the phosphor sheet and the coating solution. The coating solution was applied to form a coating layer (backside protective layer) having a thickness of 2 μm.

In the heat compression treatment, heat compression was performed using a calender under the following conditions. One of the phosphor sheets is overlapped so that the surface layer at the time of coating is in contact with the undercoat layer surface of the support, and using a calender roll (φ200 mm; metal roll), the total load is 1.6 ton, the upper roll temperature is 45 ° C., and the lower side The compression treatment was performed at a roll temperature of 45 ° C. and a feed speed of 0.3 m / min. Another phosphor sheet is superimposed on the heat-compressed sheet so that the release surface at the time of application is in contact with the surface of the compressed sheet, and the total load is 2.3 ton and the upper roll temperature is 45.
° C, lower roll temperature 45 ° C, feed rate 0.3m / min
Performed compression processing. By this heat compression, the phosphor layer became a phosphor layer (layer thickness: 310 μm) completely fused to the support via the undercoat layer. The packing density of the phosphor is 3.3
It was 5 g / cm ³ .

The same coating solution as that for the back surface protective layer is coated with 6 μm thick PET.
It was similarly coated on a film (Lumirror 6c-F53, Toray Industries, Inc.) to provide a coating layer having a thickness of 2 μm. Next, on the side opposite to the coating layer, an unsaturated polyester resin solution (Toyobo Co., Ltd., Byron 30SS) was applied and dried to form an adhesive layer (adhesive application weight 2 g / m ² ). The PET film was adhered on the phosphor layer via an adhesive layer using a laminating roll, and then an emboss pattern was formed. Thus, a protective layer having a surface roughness (Ra = 0.2 μm) was formed, and the panel was completed.

(Emission Performance Measurement Method) After irradiating the radiation image conversion panel with a tungsten bulb and X-rays at a tube voltage of 80 kVp (10
Excited with He-Ne laser light (wavelength = 632.8 nm) and stimulated emission from the radiation image conversion panel was received by a photodetector (photomultiplier tube with a spectral sensitivity of S-5) from each of the front and back surfaces. . The received light was converted into an electric signal to obtain a front image and a back image. The graininess (1C-WINER) and emission intensity (QL) of the obtained front and back images of 10 mR were measured and compared. Table 1 shows the results.

[0048]

[Table 1]

As shown in Table 1, when the average value of the 85-degree glossiness of the release surface is 56 or more, the graininess (WINER) decreases, and when the average value of the 85-degree glossiness becomes 58 or more, It has been found to exhibit more favorable granularity.

[Brief description of the drawings]

FIG. 1 shows a phosphor sheet formed on a temporary support.

FIG. 2 is a diagram showing one configuration of a radiation image conversion panel of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Temporary support 11 Support 12 Phosphor sheet 12a Phosphor sheet back 13 Phosphor sheet 13a Phosphor sheet back

Claims (4)

[Claims] 1. A radiation image conversion panel comprising at least a support and a phosphor layer formed by laminating a plurality of phosphor sheets on the support, wherein the phosphor layer is released from the temporary support. Wherein the release surfaces of the phosphor sheets obtained in this manner are overlapped with each other, and the average value of the 85-degree glossiness of the release surfaces of the phosphor sheets is 56 or more. Image conversion panel. 2. The radiation image conversion panel according to claim 1, wherein the average value of the 85 degree glossiness is 58 or more. 3. The radiation image conversion panel according to claim 1, wherein the phosphor layer comprises the two phosphor sheets. 4. The radiation image conversion panel according to claim 1, wherein the radiation image conversion panel is for double-sided condensing reading.