JPH0664197B2 - Radiation image conversion panel - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a radiation image conversion panel used in a radiation image conversion method using a stimulable phosphor, and more specifically, the present invention relates to a conductive image The present invention relates to a radiation image storage panel provided with a polymer layer.

[Technical Background of the Invention] As a method for obtaining a radiographic image as an image, a so-called radiographic method has conventionally been used which uses a combination of a radiographic film having an emulsion layer made of a silver salt photosensitive material and an intensifying screen. There is. Recently, as an alternative to the radiographic method, a radiographic image conversion method using a stimulable phosphor, as described in, for example, JP-A-55-12145, has been attracting attention. This radiation image conversion method utilizes a radiation image conversion panel (stimulable phosphor sheet) having a stimulable phosphor, and irradiates the radiation transmitted through the subject or the radiation emitted from the subject with the radiation of the panel. Radiation accumulated in the stimulable phosphor by absorbing the stimulable phosphor in a time series and then exciting the stimulable phosphor with electromagnetic waves (excitation light) such as visible light and infrared rays. Energy is emitted as fluorescence (stimulated luminescence), the fluorescence is photoelectrically read to obtain an electric signal, and the obtained electric signal is imaged.

The radiation image conversion method described above has an advantage that a radiation image having a large amount of information can be obtained with a much smaller exposure dose than in the case of the conventional radiographic method. Therefore, this radiographic image conversion method is extremely useful in direct medical radiography such as X-ray radiography for the purpose of medical diagnosis.

The radiation image conversion panel used in the above radiation image conversion method has, as a basic structure, a support and a phosphor layer provided on one surface thereof. The surface of the phosphor layer opposite to the support (the surface not facing the support) is generally provided with a transparent protective film made of a polymer substance, Protects against optical alteration or physical shock.

The phosphor layer is composed of a stimulable phosphor and a binder which contains and supports the stimulable phosphor in a dispersed state. The stimulable phosphor absorbs radiation such as X-rays and then emits visible light and It has a property of emitting light (stimulated luminescence) when irradiated with electromagnetic waves (excitation light) such as infrared rays. Therefore,
Radiation transmitted through the subject or emitted from the subject is absorbed by the phosphor layer of the radiation image conversion panel in proportion to the amount of radiation, and the radiation image of the subject or subject is radiated on the radiation image conversion panel. It is formed as an accumulated image of energy. This accumulated image can be emitted as a stimulant by exciting it in time series with the electromagnetic wave, and the accumulated image of radiation energy is imaged by optically reading this stimulant and converting it into an electric signal. Can be converted.

The phosphor layer can also be formed by vapor deposition of a stimulable phosphor on a support instead of the method of coating by using a binder as described above. Specifically, for example, the formation of the phosphor layer is performed by the known PFC ARCIA AND LHBRI.
Vacuum deposition method (ELECTRONICS AND OPTICS, T
hin Solid Film, 115 (1984) 89-95).

The above-mentioned radiation image conversion method is a very advantageous image forming method as described above, but the radiation image conversion panel used in this method has high sensitivity as well as the intensifying screen used in the conventional radiographic method. It is desirable that it gives an image excellent in image quality (sharpness, graininess, etc.).

When carrying out the radiation image conversion method, the radiation image conversion panel applies radiation (records a radiation image), irradiates excitation light (reads a recorded radiation image), and erases light (erases the remaining radiation image). In the radiation image information recording / reproducing apparatus having a cycle of, the apparatus is moved in a state of being sandwiched by a conveying system including a roll and an endless belt. The panel is repeatedly used in this cycle, and the panels are usually stacked and stored after each cycle.

In general, it is desirable to use a plastic film such as a polyethylene terephthalate film or various papers as the support material from the viewpoint of flexibility required when the radiation image conversion panel is transported.

When the radiation image conversion panel is laminated or transferred from the laminated state to the conveyance system in the repeated use including the conveyance and lamination as described above, the surface of one panel (phosphor layer surface or protective film surface) And the back surface of the other panel (support surface), the edge of the panel and the front surface or the back surface of the other panel, and the panel and the transport member (roll,
Due to physical contact such as rubbing with a belt or the like), the front surface of the panel made of a polymer substance tends to be negatively charged, while the back surface tends to be positively charged. This charging phenomenon causes various problems in the implementation of the radiation image conversion method.

For example, as a result of the surface of the radiation conversion panel being charged, when the panels are transferred from the stacked state to the transport system, the front surface of the panel and the back surface of another panel are in close contact with each other and are fed into the transport system in a state of overlapping two sheets. It becomes easy, and it becomes impossible to perform normal operation thereafter. In addition, normally, the panel is read by irradiating the excitation light from the surface of the phosphor layer side, but dust in the air is likely to adhere to the charged panel surface, and the excitation light is emitted by the dust adhered to the surface during reading. Are scattered, the image quality of the obtained image is remarkably deteriorated. Furthermore, as the panel discharges,
Noise (static marks) will be generated in the obtained image.

In addition, in order to solve the above-mentioned problems, radiation image conversion panels having various aspects provided with an antistatic function have already been proposed. For example, a radiation image conversion panel (Japanese Patent Application No. 60-106751) in which an antistatic film made of a conductive inorganic oxide is provided on the surface of the protective film side of the panel, or a phosphor layer of a support of the panel is used. The surface on the opposite side to the side provided,
Alternatively, a radiation image conversion panel provided with an antistatic layer made of a conductive material and having a surface electric resistivity of a constant value (10 ¹¹ ohm) or less between the support and the phosphor layer (Japanese Patent Application No.
60-228418 and 60-228419 specification).

[Object of the Invention] An object of the present invention is to provide a radiation image conversion panel having excellent antistatic performance.

In the radiation image conversion panel having a support, a phosphor layer made of a stimulable phosphor provided on the support, and a transparent protective film, the above-mentioned object is the surface of the transparent protective film on the phosphor layer side. This can be achieved by a radiation image conversion panel characterized in that a transparent conductive polymer layer is attached to the.

In addition, the conductive polymer constituting the conductive polymer layer used in the present invention means a polymer to which conductivity is imparted by changing the molecular structure itself of the polymer.

The present invention provides a conductive polymer layer on the phosphor layer side surface of the transparent protective film attached to the excitation light incident side surface of the radiation image conversion panel, whereby the panel surface (the surface opposite to the support) is provided. ) Is to realize antistatic.

According to the present invention, it is possible to effectively prevent the charging phenomenon that occurs in the radiation image conversion panel. That is, by providing the radiation image conversion panel with the conductive polymer layer, the charged state of the surface of the panel can be maintained in an extremely stable state (state of low charge). This is because the conductive polymer layer is provided between the phosphor layer and the transparent protective layer, so that even if a large amount of charge is generated on the panel surface, the polymer layer is opposite to the surface charge in the same amount. It is presumed that the electric charge of the sign appears, and the electric charge state on the panel surface is apparently extremely small. Therefore, the attraction force due to static electricity on the surface of the phosphor layer side can be reduced. As a result, in the radiation image information recording / reproducing apparatus, it is possible to prevent the two panels from being simultaneously sent to the transport system in a state where the two panels overlap each other when the stacked panels are moved to the transport system. Further, it is possible to prevent dust and the like from adhering to the surface of the panel on the phosphor layer side, and also to prevent noise (static marks) from being generated due to discharge, thereby preventing deterioration in image quality.

In addition, the conductive polymer layer according to the present invention is provided with a conductive polymer layer at a position above the phosphor layer, that is, near the surface of the panel as described above, because the polymer itself that constitutes the conductive polymer layer is transparent. Even so, since the irradiated excitation light is transmitted almost without being blocked by this layer, the image quality can be improved without lowering the sensitivity of the panel.

[Structure of the Invention] The radiation image conversion panel of the present invention is a radiation image conversion panel having a support, a phosphor layer made of a stimulable phosphor provided on the support, and a transparent protective film as basic configurations. It is characterized in that a conductive polymer layer is provided on the surface of the transparent protective film on the phosphor layer side.

That is, the panel of the present invention has a configuration in which at least one conductive polymer layer described later is attached to any position of the panel.

A preferred embodiment of the panel of the present invention is shown in FIG.

The panel shown in FIG. 1 has a three-layer structure of a support (11), a phosphor layer (12) and a protective film (13) between a phosphor layer and a protective film of a radiation image conversion panel. In this embodiment, a conductive polymer layer (14) is attached. However, the above configuration is a representative example of the radiation image storage panel of the present invention and does not limit the present invention. For example, it goes without saying that the panel having the above structure may be further provided with an optional intermediate layer or the like.

The radiation image conversion panel of the present invention will be described below by taking the panel of the embodiment shown in FIG. 1 as an example.

The radiation image storage panel of the present invention having the above-described excellent characteristics can be manufactured by, for example, the method described below.

The support used in the present invention contains a film of a plastic material such as cellulose acetate, polyester, polyethylene terephthalate, polyamide, polyimide, triacetate, or polycarbonate; or ordinary paper, baryta paper, resin-coated paper, pigment such as titanium dioxide. Pigment paper, paper sized with polyvinyl alcohol, and the like. However, in consideration of the characteristics and handling of the radiation image storage panel as an information recording material, a particularly preferable material for the support in the present invention is a plastic film. This plastic film may be kneaded with a light absorbing substance such as carbon black, or may be kneaded with a light reflecting substance such as titanium dioxide. The former is a support suitable for a radiation image conversion panel of high sharpness type, and the latter is a support suitable for a radiation image conversion panel of high sensitivity type.

In a known radiation image conversion panel, a phosphor layer is provided in order to strengthen the bond between the support and the phosphor layer or to improve the sensitivity or image quality (sharpness, graininess) of the radiation image conversion panel. It is also practiced to apply a polymer substance such as gelatin to the surface of the support on the side to be used as an adhesion-imparting layer, or to provide a light-reflecting layer made of a light-reflecting substance such as titanium dioxide. These various layers can also be provided in the support used in the present invention.

Further, as described in JP-A-58-200200, for the purpose of improving the sharpness of the image obtained, the surface of the support on the phosphor layer side (the surface of the support on the phosphor layer side is When the adhesion-imparting layer or the light-reflecting layer is provided, it means the surface thereof, and fine irregularities may be uniformly formed.

Next, a phosphor layer is formed on the support. The phosphor layer is basically a layer made of a binder which contains and supports stimulable phosphor particles in a dispersed state.

The phosphor layer may be a layer formed by vapor deposition of a stimulable phosphor on a support as described above.

The stimulable phosphor is a phosphor that emits stimulated emission when irradiated with excitation light after being irradiated with radiation as described above, but from a practical viewpoint, the wavelength is in the range of 400 to 900 nm. A phosphor that exhibits stimulated emission in the wavelength range of 300 to 500 nm by excitation light is desirable. Examples of the stimulable phosphor used in the radiation image conversion panel of the present invention include SrS: Ce, which is described in US Pat. No. 3,859,527.
Sm, SrS: Eu, Sm, ThO ₂ : Er, and La ₂ O ₂ S: Eu, Sm, ZnS: Cu, Pb, Ba described in JP-A-55-12142.
O · xA ₂ O ₃ : Eu (however, 0.8 ≦ x ≦ 10), and
M ^II O ・ xSiO ₂ : A (However, M ^II is Mg, Ca, Sr, Zn, C
d, or Ba, A is Ce, Tb, Eu, Tm, Pb, T, B
i or Mn, and x is 0.5 ≦ x ≦ 2.5), and described in JP-A-55-12143 (Ba
_{1-x-y, Mg x} , Ca y) FX: aEu 2+ ( although, X is C
And at least one of Br and x and y
Is 0 <x + y ≦ 0.6 and xy ≠ 0, and a is 10
⁻⁶ ≦ a ≦ 5 × 10 ⁻² ), LnOX: xA described in JP-A-55-12144 (where Ln is at least one of La, Y, Gd, and Lu, X is at least one of C and Br, A is Ce
And at least one of Tb and x is 0 <
x <0.1), as described in JP-A-55-12145 (Ba _1-x , M).
⁺² _x ) FX: yA (wherein M ²⁺ is at least one of Mg, Ca, Sr, Zn, and Cd, X is at least one of C, 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), JP-A-55-160078. M ^II FX xA: y
Ln [However, M ^II is Ba, at least one of Ca, Sr, Mg, Zn, and Cd, A is BeO, MgO, CaO, SrO, BaO, Z
nO, A ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ , SiO
₂ , TiO ₂ , ZrO ₂ , GeO ₂ , SnO ₂ , Nb ₂ O ₅ , Ta
_At least one of ₂ O ₅ and ThO ₂ , Ln is E
u, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Sm, and G
at least one of d, X is at least one of C, Br, and I, and x and y are each 5
X10 ^-5 ≤ x ≤ 0.5, and 0 <y ≤ 0.2], a phosphor represented by the composition formula of JP-A-56-116777 (Ba _1-x , M
^II _x ) F ₂ · aBaX ₂ : yEu, zA [M ^II is at least one of beryllium, magnesium, calcium, strontium, zinc, and cadmium, X is at least one of chlorine, bromine, and iodine, A is at least one of zirconium and scandium, 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 ≦ 10 ⁻² ], the phosphor represented by the composition formula, which is 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, and X is at least one of chlorine, bromine, and iodine. Yes,
a, x, y, and z are 0.5 ≦ a ≦ 1.25 and 0 ≦, respectively.
x ≦ 1, 10 ⁻⁶ ≦ y ≦ 2 × 10 ⁻¹ , and 0 <z ≦ 2 ×
The phosphor represented by the composition formula of 10 ⁻¹ ] is described in JP-A-57-23675 (Ba _1-x , M
^II _x ) F ₂ · aBaX ₂ : yEu, zA [M ^II is at least one of beryllium, magnesium, calcium, strontium, zinc, and cadmium, X is at least one of chlorine, bromine, and iodine, A is at least one of arsenic and silicon, and a, x,
y and z are 0.5 ≦ a ≦ 1.25, 0 ≦ x ≦ 1, 1 respectively
^{0 -6 ≦ y ≦ 2 × 10} -1, and 0 <phosphor represented by a composition formula of z ≦ 5 is a × 10 ^-1], M ^III OX that is described in JP-A-58-69281 : xCe
[However, M ^III is Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, E
It is at least one trivalent metal selected from the group consisting of r, Tm, Yb, and Bi, X is one or both of C and Br, and x is 0 <x ≦ 0.1.
And a Ba _1-x M described in JP-A-58-206678.
_{x / 2} L _{x / 2} FX: yEu ²⁺ [where M is Li, Na, K,
Rb represents at least one alkali metal selected from the group consisting of Cs; L represents Sc, Y, La, Ce, Pr, Nd,
Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, A, Ga,
Represents at least one trivalent metal selected from the group consisting of In and T; X represents at least one halogen selected from the group consisting of C, Br, and I; and x represents 10 ⁻² ≦ x ≦ 0.5, y is 0 <y ≦ 0.1]
A phosphor represented by the composition formula of BaFX.xA: yEu described in JP-A-59-27980.
²⁺ [wherein X is at least one halogen selected from the group consisting of C, Br, and I; A is a calcined product of a tetrafluoroboric acid compound; and x is
10 ⁻⁶ ≦ x ≦ 0.1, y is 0 <y ≦ 0.1], a phosphor represented by the composition formula BaFX · xA: yEu described in JP-A-59-47289.
²⁺ [wherein X is at least one halogen selected from the group consisting of C, Br and I; A is a monovalent or divalent metal of hexafluorosilicic acid, hexafluorotitanic acid and hexafluorozirconic acid] be burned material of at least one compound selected from hexafluoro compound group consisting of a salt; and, x is 10 ^-6 ≦
x ≦ 0.1, y is 0 <y ≦ 0.1], a phosphor represented by the composition formula: BaFX · xNaX ′ described in JP-A-59-56479:
aEu ²⁺ [where X and X ′ are C and B, respectively]
at least one of r and I, and x and a are 0 <x ≦ 2 and 0 <a ≦ 0.2, respectively]
And a phosphor represented by the composition formula of M ^II FX.xNa described in JP-A-59-56480.
X ′: yEu ²⁺ : zA [wherein M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr, and Ca; X and X ′ are C, Br, and I, respectively.
Is at least one halogen selected from the group consisting of; A is at least one transition 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 ⁻² ], the phosphor represented by the composition formula M ^II FX.aM described in JP-A-59-75200. ^II
X ′ · bM ′ ^II X ″ ₂ · cM ^II X ₃ · xA: yEu ²⁺ [wherein M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr, and Ca; M ^I Is Li, N
a, K, Rb, and is at least one alkali metal selected from the group consisting of Cs; M ^'II is at least one trivalent metal selected from the group consisting of Be and Mg; M
^III is at least one trivalent metal selected from the group consisting of A, Ga, In, and T; A is a metal oxide; X is at least one selected from the group consisting of C, Br, and I Halogen; X ′, X ″, and X
Is at least one halogen selected from the group consisting of F, C, 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] and a phosphor represented by the composition formula M ^II X ₂ · aM described in JP-A-60-84381.
^II X ′ ₂ : xEu ²⁺ [wherein M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; X and X ′ are selected from the group consisting of C, Br and I At least one kind of halogen, and X ≠
X ′; and a is 0.1 ≦ a ≦ 10.0, x is 0 <x ≦
Stimulable phosphor represented by a composition formula of which is ^{0.2], M II FX · aM} I that are described in JP-A-60-101173
X ′: xEu ²⁺ [wherein M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; 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 C, Br and I; X '
Is at least one halogen selected from the group consisting of F, C, Br and I; and a and x are 0 ≦ a ≦ 4.0 and 0 <x ≦ 0.2, respectively]. Phosphor, M ^I X: xBi described in Japanese Patent Application No. 60-70484 by the present applicant [where 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 C, Br and I, and x is a numerical value in the range of 0 <x ≦ 0.2]. You can

Further, the M described in the above-mentioned JP-A-60-84381
^II X ₂ · aM ^II X ′ ₂ : xEu ²⁺ stimulable phosphor even if the following additives are contained in the following ratio per 1 mol of M ^II X ₂ · aM ^II X ′ ₂ Good.

JP bM ^{I X} that are described in 60-166379 JP "(where, M ^I is at least one alkali metal selected from the group consisting of Rb and Cs, X" is F, C, Br and I Is at least one halogen selected from the group consisting of, and b is 0 <b≤10.0);
BKX ″ · cMgX ₂ · dM described in Japanese Patent No. 221483
^III X '3 _(provided that 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 both F, C, Br and I Is at least one halogen selected from the group consisting of, and b, c and d are each 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 (where y is 2 × 10 ⁻⁴ ≦ y ≦ 2 ×).
10 ^-1 at a); bA which are described in JP 60-228593 Laid (where, A is an oxide of at least one selected from the group consisting of SiO ₂ and P ₂ O _5, and b
Is 10 ⁻⁴ ≦ b ≦ 2 × 10 ⁻¹ ); JP-A-60-120883
BSiO (where b is 0 <b ≦ 3
X10 ⁻² ); bSnX ″ ₂ (where X ″ is F, c, Br and I described in JP-A-61-120885).
At least one halogen selected from the group consisting of, and b is 0 <b ≦ 10 ⁻³ ); Japanese Patent Application No. 60-78.
BCsX ″ · cSnX ₂ (where X ″ and X are each at least one halogen selected from the group consisting of F, C, Br and I, and b and c are 0 <b ≦ 10.0 and
10 ⁻⁶ ≦ c ≦ 2 × 10 ⁻² ); and Japanese Patent Application No. 60-78.
BCsX ″ · yLn ³⁺ (where X ″ is at least one halogen selected from the group consisting of F, C, Br and I, and Ln is Sc, Y, Ce,
Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and at least one rare earth element selected from the group consisting of Lu, and b and y are 0 <b ≦ 10.0 and
10 ⁻⁶ ≦ y ≦ 1.8 × 10 ⁻¹ ).

Among the above-mentioned stimulable phosphors, the divalent europium-activated alkaline earth metal halide-based phosphor and the rare earth element-activated rare earth oxyhalide-based phosphor are particularly preferable because they exhibit high-intensity stimulated emission. However, the stimulable phosphor used in the present invention is not limited to the above-mentioned phosphor, and may be any phosphor that exhibits stimulated emission when irradiated with excitation light after irradiation with radiation. It may be.

Examples of the binder for the phosphor layer include proteins such as gelatin,
Polysaccharides such as dextran or natural polymer substances such as gum arabic; and polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethyl cellulose, vinylidene chloride / vinyl chloride copolymer, polyalkyl (meth) acrylate, vinyl chloride / vinyl acetate There may be mentioned binders represented by synthetic polymeric substances such as copolymers, polyurethanes, cellulose acetate butyrate, polyvinyl alcohol, linear polyesters and the like. Particularly preferred among such binders are nitrocellulose, linear polyesters, polyalkyl (meth) acrylates, mixtures of nitrocellulose and linear polyesters and mixtures of nitrocellulose and polyalkyl (meth) acrylates. is there.
Note that these binders may be crosslinked with a crosslinking agent.

The phosphor layer can be formed on the support by the following method, for example.

First, the stimulable phosphor and the binder are added to an appropriate solvent and mixed sufficiently to prepare a coating solution in which the phosphor particles are uniformly dispersed in the binder solution.

Examples of the solvent for preparing the coating solution include lower alcohols such as methanol, ethanol, n-propanol, and n-butanol; chlorine atom-containing hydrocarbons such as methylene chloride and ethylene chloride; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. Ester of lower fatty acid and lower alcohol such as methyl acetate, ethyl acetate, butyl acetate; ether such as dioxane, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether; and mixtures thereof.

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

It is possible to form the phosphor layer by using a conductive polymer instead of the binder. However, since the adhesive force of the polymer is smaller than that of the above-mentioned binder, the phosphor is not sufficiently bound when the polymer is used alone as the binder, and in order to compensate for this adhesive force. When this polymer is used in combination with another binder, the antistatic effect, which is a feature of the present invention, cannot be sufficiently obtained, and practically preferable results cannot be obtained. Therefore, it is difficult to use the polymer as the binder of the phosphor when forming the phosphor layer with a usual mixing ratio of the phosphor and the binder.

The above-mentioned coating liquid contains a dispersant for improving the dispersibility of the phosphor in the coating liquid, and also for improving 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 purpose include phthalic acid, stearic acid, caproic acid, lipophilic surfactants and the like. And as an example of a plasticizer,
Phosphoric acid esters such as triphenyl phosphate, tricresyl phosphate and diphenyl phosphate; phthalic acid esters such as diethyl phthalate and dimethoxyethyl phthalate; glycolic acid esters such as ethyl phthalyl ethyl glycolate and butyl phthalyl butyl glycolate; Examples thereof include polyesters of ethylene glycol and adipic acid, polyesters of polyethylene glycol such as diethylene glycol and succinic acid, and polyesters of aliphatic dibasic acid.

The coating solution containing the phosphor and the binder prepared as described above is then uniformly applied to the surface of the support to form a coating film of the coating solution. This coating operation can be performed by using an ordinary coating means such as a doctor blade, a roll coater or a knife coater.

Then, the formed coating film is gradually heated and dried to complete the formation of the stimulable phosphor layer on the support.

The layer thickness of the stimulable phosphor layer varies depending on the characteristics of the intended radiation image conversion panel, the type of stimulable phosphor, the mixing ratio of the binder and the phosphor, etc., but is usually 20 μm to 1 mm. . However, this layer thickness is preferably in the range of 50 to 500 μm.

The stimulable phosphor layer does not necessarily have to be formed by directly applying the coating solution on the support as described above, and for example, the coating solution may be separately formed on a sheet such as a glass plate, a metal plate or a plastic sheet. After forming the phosphor layer by applying and drying, the support may be bonded to the phosphor layer by pressing it onto the support or using an adhesive.

Next, a conductive polymer layer is provided on the surface of the phosphor layer opposite to the side in contact with the support.

The conductive polymer layer means a layer made of a polymer in which the polymer itself has conductivity and the molecular structure of the polymer is a structure in which electrons and holes easily move. Therefore, the conductive polymer layer according to the present invention,
A layer made of a conductive polymer, which is a composite material produced by dispersing a commonly used conductive substance such as a surfactant, or the above-mentioned Japanese Patent Application No. 60-106751.
No. 60-228418, No. 60-228419, and the like, and the constitution itself is different from the antistatic film having the constitution described in each specification. However, the conductive polymer according to the present invention may contain the above-mentioned conductive substance to form a conductive polymer layer.

The conductive polymer that can be used in the present invention is not particularly limited as long as it has the above-mentioned function.

The preferred conductive polymer used in the present invention,
For example, conductive acrylic resin (trade name; Colcoat NR
-121, manufactured by Colcoat Co., Ltd., or a polymer containing a siloxane bond (—Si—O—Si—) (trade name; Colcoat R, manufactured by Colcoat Co., Ltd.). Here, the polymer containing a siloxane bond is a monomer before use and solidifies into a polymer having a three-dimensional network structure in the process of forming a coating film.

For the conductive polymer layer, a coating solution containing the conductive polymer is prepared using a suitable solvent, and the coating solution is uniformly coated on the surface of the phosphor layer using the usual coating means described above. It can be obtained by drying. In this way, the conductive polymer layer (coating film) can be formed.

Although the layer thickness of the conductive polymer layer varies depending on the position to be arranged on this layer panel or the characteristics of the polymer itself, it is generally preferable that the layer thickness is in the range of 0.5 to 20 μm, and particularly 1 to 10 μm. It is preferably in the range. This will reduce the surface resistance of the conductive polymer layer.
It can be less than 10 ⁹ ohms.

Next, a transparent protective film is provided on the surface of the conductive polymer layer opposite to the side in contact with the phosphor layer in order to physically and chemically protect the panel.

The transparent protective film may be, for example, a cellulose derivative such as cellulose acetate or nitrocellulose; or a transparent polymer material such as polymethylmethacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyvinyl acetate, or vinyl chloride / vinyl acetate copolymer. It can be formed by a method in which a solution prepared by dissolving a different polymer substance in a suitable solvent is applied to the surface of the intermediate layer. Alternatively, it can also be formed by a method of adhering a transparent thin film formed in advance from polyethylene terephthalate, polyethylene, vinylidene chloride, polyamide or the like to the surface of the conductive polymer layer with an appropriate adhesive. The thickness of the transparent protective film is preferably about 1 to 30 μm.

Also, two conductive polymer layers may be provided on the screen. For example, as this mode, in the panel shown in FIG. 1, a second conductive polymer layer (which may also serve as an undercoat layer) is further provided between the support and the phosphor layer.
The aspect which provided is mentioned. The antistatic effect can be further enhanced by providing two or more conductive polymer layers.

As described above, the panel of the present invention has been described by taking a mode in which a conductive polymer layer is attached to a panel having a three-layer structure composed of a support, a phosphor layer and a protective film as a main example. As described above, the panel of the present invention includes a panel in which a conductive polymer layer is provided on the panel having a body structure.

As shown in FIG. 2, the radiation image storage panel of the present invention may be provided with edge stickings 16a, 16b made of a conductive polymer on at least one side end (side surface) of the panel. In particular, it is preferable that the positions where the edges are attached are provided along the ends of the front end portion and the rear end portion with reference to the transport direction of the panel. The antistatic effect according to the present invention can be further improved by providing this edge sticking. That is, by providing the edge sticking on both ends of the panel, contact between the edge sticking portion and the carrying member easily occurs in the process of carrying the panel, so that the electric charges that are likely to be accumulated inside the panel are charged to the edge sticking and the carrying member. It is possible to promptly release it to the outside of the panel through contact with. Therefore, the antistatic function of the panel can be further enhanced by attaching the polymer layer and the edge sticking having the conductive property to the panel.

The radiation image conversion panel of the present invention is disclosed in JP-A-55-1635.
No. 00, JP-A-57-96300, etc.
It may be colored with a coloring agent, and this coloring can improve the sharpness of the obtained image.
The radiation image conversion panel of the present invention is disclosed in JP-A-55-146447.
As described in the publication, white powder may be dispersed in the phosphor layer for the same purpose.

Next, examples and comparative examples of the present invention will be described. However,
Each of these examples does not limit the invention.

Example 1 Methyl ethyl ketone was added to a mixture of a powdery divalent europium-activated barium fluorobromide phosphor (BaFBr: 0.001Eu ²⁺ ) and a linear polyester resin, and the degree of nitrification was further adjusted to 11.5.
% Nitrocellulose was added to prepare a dispersion containing the phosphor in a dispersed state. Next, tricresyl phosphate, n-butanol and methyl ethyl ketone were added to this dispersion, and the mixture was thoroughly stirred and mixed using a propeller mixer to uniformly disperse the phosphor, and to mix the binder with the phosphor. A coating solution having a viscosity of 1:20 and a viscosity of 25 to 35 PS (25 ° C) was prepared. Next, the coating liquid was uniformly applied onto a carbon black-kneaded polyethylene terephthalate sheet (support, thickness: 250 μm) placed horizontally on a glass plate using a doctor blade. After the coating, the support on which the coating film was formed was placed in a dryer, and the temperature inside the dryer was gradually increased from 25 ° C to 100 ° C to dry the coating film. Thus, a phosphor layer having a layer thickness of 250 μm was formed on the support.

Next, conductive acrylic resin (trade name; Colcoat NR = 1
Methyl ethyl ketone was added to 50 parts by weight of 21 Colcoat Co., Ltd. to prepare a coating solution containing a conductive acrylic resin.

This coating solution was applied on the phosphor layer by the same operation as above, and then dried to form a conductive polymer layer having a layer thickness of 2 μm.

In addition, a transparent polyethylene terephthalate film (thickness: 10 μm, with a polyester adhesive) is placed on the conductive polymer layer with the adhesive layer side facing down, and is adhered to protect the transparency. A film was formed.

In this way, the radiation image storage panel of the present invention composed of the support, the phosphor layer, the conductive polymer layer, and the transparent protective film in this order was manufactured (see FIG. 1).

Comparative Example 1 By performing the same operation as in the method of Example 1 except that the conductive polymer layer is not provided in Example 1,
A radiation image conversion panel composed of a support, a phosphor layer and a transparent protective film was manufactured in this order.

Next, each of the radiation image conversion panels obtained as described above was subjected to the transport characteristic test and the image unevenness test described below.

Conveyance characteristic test The conveyance characteristic test was conducted using a static tester as shown in FIG.

FIG. 3 is a schematic diagram of a static tester.

In FIG. 3, the static tester has a conveying means 31, 31 '.
And a potential measuring means 32. Carrier 3
Reference numerals 1 and 31 'include urethane rubber rolls 33a and 33b, an endless belt 34 stretched by the rolls, and a phenol resin auxiliary roll 35. The potential measuring means 32 is composed of a detection unit 36, and a voltmeter 37 and a recorder 38 connected to this detection unit.

The radiation characteristics are evaluated by feeding the radiation image conversion panel 39 to the above-mentioned transportation means 31 and 31 'and repeatedly transporting the radiation image conversion panel 39 100 times in the left-right direction (the direction of the arrow in the figure), and then detecting it on the surface of the panel (surface on the protective film side). The measurement was performed by bringing the parts 36 into contact with each other and measuring the surface potential (KV) thereof.

Image unevenness test The radiation image conversion panel irradiated with X-rays was sent to the static tester (installed in a dark room) shown in Fig. 3 and repeatedly conveyed 10 times in the same manner as above, and then the radiation image conversion method was performed on the panel. did. Then, the obtained image was evaluated by the presence or absence of generation of noise (static mark due to discharge). The above test was carried out in an atmosphere having a temperature of 10 ° C. and a relative humidity of 20%, and the radiation image conversion method was carried out using a radiation image reader (FCR101, manufactured by Fuji Photo Film Co., Ltd.).

The above results are summarized in Table 1.

As is clear from the results in Table 1, the radiation image storage panel of the present invention provided with a conductive polymer layer (Example 1).
In each case, the potential difference on the panel surface was small, and the generation of static marks was not observed, and an excellent antistatic effect was obtained. On the other hand, in the radiation image storage panel (Comparative Example 1) to which the conductive polymer layer was not provided, the potential difference on the panel surface was large, and many static marks were generated, showing a markedly charged state.

[Brief description of drawings]

FIG. 1 is a sectional view showing various structural examples of a radiation image conversion panel according to the present invention. FIG. 2 is a cross-sectional view showing a mode in which the radiation image conversion panel according to the present invention is further provided with an edge attachment. FIG. 3 is a diagram schematically showing a static tester for testing and evaluating the transport characteristics of the radiation image conversion panel. 11: Support, 12: Phosphor layer, 13: Transparent protective film 14: Conductive polymer layer 16a, 16b: Edge attachment 31, 31 ': Transfer means, 32: Potential measuring means 39: Radiation image conversion panel

Claims (4)

[Claims] 1. A radiation image conversion panel having a support, a phosphor layer comprising a stimulable phosphor provided on the support, and a transparent protective film, the surface of the transparent protective film on the phosphor layer side. A radiation image conversion panel, wherein a transparent conductive polymer layer is attached to the. 2. The radiation image storage panel according to claim 1, wherein the conductive polymer layer is a layer made of a conductive acrylic resin or a polymer having a siloxane bond. 3. The conductive polymer layer has a layer thickness of 0.5 to 20 μm.
The radiation image conversion panel according to claim 1, which is in the range of m. 4. The radiation image conversion panel according to claim 1, wherein a side surface of the radiation image conversion panel is provided with an edge sticking made of a conductive polymer.