JPH0652320B2 - 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.

[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, the above radiographic method has been used. Recently, as one of the alternatives to the above radiography,
For example, a radiation image conversion method using a stimulable phosphor as described in JP-A-55-12145 has come to be noticed. This radiation image conversion method is
A radiation image conversion panel (stimulable phosphor sheet) having a stimulable phosphor is used. Radiation transmitted through an object or emitted from a subject is absorbed by the stimulable phosphor of the panel. After that, the stimulable phosphor is excited with electromagnetic waves (excitation light) such as visible light and infrared rays in time series, so that the radiation energy accumulated in the stimulable phosphor is converted into fluorescence (stimulated light). Emission)
This 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 very useful particularly in direct medical radiography such as X-ray photography 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 chemical alteration or physical shock.

The phosphor layer is usually composed of a stimulable phosphor and a binder that contains and supports the stimulable phosphor in a dispersed state. The stimulable phosphor is visible after absorbing radiation such as X-rays. It has the property of emitting light (stimulated luminescence) when irradiated with electromagnetic waves (excitation light) such as light rays and infrared rays. Therefore, the 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 radiation dose, and the radiation image of the subject or the subject is displayed on the radiation image conversion panel. Are formed as an accumulated image of radiation energy. This accumulated image can be emitted as stimulated emission by being excited in time series by the electromagnetic wave, and the accumulated image of radiation energy can be imaged by photoelectrically reading this stimulated emission and converting it into an electric signal. Can be converted.

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 desired to provide an image having excellent image quality (sharpness, graininess, etc.).

In 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). It is used repeatedly in this cycle. Then, the transfer of the radiation image conversion panel to each step is carried out by the transport system, and after the completion of one cycle, the panels are usually stacked and stored.

In repeated use consisting of such conveyance and lamination,
When the radiation image conversion panels are stacked or transferred from the stacked state to the transport system, rubbing between the front surface (protective film side surface) of one panel and the back surface (support side surface) of another panel, and The front surface and the back surface of the panel are easily damaged by physical contact such as rubbing between the edge and the front surface or the back surface of another panel. Usually, reading of the radiation image conversion panel by irradiation of excitation light is performed from the transparent protective film side surface, and physical damage caused on the protective film side surface causes scattering of excitation light at the time of reading. This tends to cause deterioration of image quality such as deterioration of image uniformity.

Therefore, regarding the radiation image conversion panel, it is desired to prevent damage to the protective film side surface of the panel as much as possible during transportation and lamination in the reading system.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a radiation image conversion panel having improved scratch resistance on the protective film side surface.

Another object of the present invention is to provide a radiation image conversion panel having a protective film side surface with high hardness.

In the radiation image conversion panel having a support, a phosphor layer containing a stimulable phosphor and a protective film in this order, the protective film side surface of the panel has an inorganic nitride, an inorganic carbide, an inorganic substance. It is composed of at least one compound selected from the group consisting of oxides and inorganic fluorides, and has a film thickness of 50.
0-2000 angstrom (however, 400-900
An odd multiple of 1/4 of the wavelength of the excitation light in the range of nm, that is,
nλ / 4 = 1, 3, 5, ~~~~~~: λ = wavelength of excitation light (excluding a film thickness corresponding to an optical film thickness). This can be achieved by the radiation conversion panel of the present invention.

INDUSTRIAL APPLICABILITY According to the present invention, a thin film made of any one of inorganic nitride, inorganic carbide, inorganic oxide and inorganic fluoride is provided on the surface of the radiation image storage panel on the side of the protective film, so that the panel can be repeatedly used for transportation and lamination. In this case, it is possible to remarkably prevent the occurrence of scratches on the surface of the panel on the excitation light irradiation side.

That is, in the present invention, the surface hardness on the protective film side can be increased by attaching a thin film made of a metal inorganic compound to the protective film side surface of the panel by a vapor deposition method or the like.

Therefore, even if the panel surface comes into contact with the back surface or the edge of another panel in the radiation image recording / reproducing apparatus, it is possible to remarkably prevent the occurrence of damage such as scratches on the panel surface. Further, it is possible to prevent the deterioration of the image quality due to the damage on the panel surface.

[Structure of the Invention] The radiation image storage panel of the present invention having the preferable characteristics described above can be manufactured, for example, by the method described below.

The support used in the present invention can be arbitrarily selected from various materials used as a support for intensifying screens in conventional radiography or various materials known as a support for radiographic image conversion panels. . Examples of such materials include cellulose acetate, polyester,
Films of plastic substances such as polyethylene terephthalate, polyamide, polyimide, triacetate and polycarbonate, metal sheets such as aluminum foil and aluminum alloy foil, ordinary paper, baryta paper, resin coated paper, pigment paper containing pigments such as titanium dioxide, Examples thereof include 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. The surface of the support is coated with a polymeric substance such as gelatin to form an adhesion-imparting layer, or a light-reflecting layer made of a light-reflecting substance such as titanium dioxide, or a light-absorbing substance such as carbon black. Providing a light absorption layer is also performed. Also for the support used in the present invention, these various layers can be provided.

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 an adhesion-imparting layer, a light-reflecting layer or a light-absorbing layer is provided, it means the surface thereof),
Fine irregularities may be formed uniformly.

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.

As for the stimulable phosphor, there is a phosphor showing a stimulable phosphor 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. It is preferable that the phosphor emits stimulated emission in the wavelength range of 300 to 500 nm by the excitation light. Examples of stimulable phosphors used in the radiation image storage panel of the present invention include SrS: Ce, Sm, SrS: Eu, Sm and Th described in US Pat. No. 3,859,527.
O ₂ : Er, and La ₂ O ₂ S: Eu, Sm, Zn described in JP-A-55-12142.
S: Cu, Pb, BaO.xAl ₂ O ₃ : Eu (provided that 0.8 ≦ x ≦ 10) and M ^II O.xSi
O ₂ : A (however, M ^II is Mg, Ca, Sr, Zn, C
d, or Ba, A is Ce, Tb, Eu, Tm,
Pb, Tl, Bi, or Mn, and x is 0.5 ≦
x ≦ 2.5), as described in JP-A-55-12143 (Ba).
_{1-xy, Mg x, Ca} y) FX: aEu 2+ ( although, X is at least one of Cl and Br, x and y, 0 <x + y ≦ 0.6 and xy ≠ 0,
And a is 10 ⁻⁶ ≦ a ≦ 5 × 10 ⁻² ), LnO described in JP-A-55-12144.
X: xA (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). 55-12145 (Pa (Ba)
_1-X , M ²⁺ _x ) FX: yA (where M ²⁺ is M
At least one of g, Ca, Sr, Zn, and Cd, X is at least one of Cl, Br, and I, A is Eu, Tb, Ce, Tm, Dy, Pr, Ho,
At least one of Nd, Yb, and Er, and x is 0 ≦ x ≦ 0.6, y is 0 ≦ y ≦ 0.2), JP-A-55-160078. M ^II
FX xA: yLn [However, M ^II is Ba, Ca, S
at least one of r, Mg, Zn, and Cd,
A is BeO, MgO, CaO, SrO, BaO, Zn
O, Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ ,
_{SiO 2, TlO 2, ZrO 2} , GeO 2, SnO 2,
At least one of Nb ₂ O ₅ , Ta ₂ O ₅ , and ThO ₂ , and Ln is Eu, Tb, Ce, Tm, Dy, P.
At least one of r, Ho, Nd, Yb, Er, Sm, and Gd, X is at least one of Cl, Br, and I, and x and y are each 5 × 10 5.
^-5 ≦ x ≦ 0.5, and 0 ≦ y ≦ 0.2], which is described in JP-A-56-116777 (B).
a _1-x , M ^II _x ) F ₂ · aBaX ₂ : yEu, zA
[Wherein 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 ], which is described in JP-A-57-23673 (Ba).
_1-x , M ^II _x ) F2 · aBaX ₂ : yEu, zB [wherein M ^II is beryllium, magnesium, calcium,
At least one of strontium, zinc, and cadmium, X is at least one of chlorine, bromine, and iodine, and 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 × 10 ⁻¹ ], the phosphor represented by the composition formula described in JP-A-57-23675 (Ba).
_1-x , M ^II _x ) F2 · aBaX ₂ : yEu, zA [where M ^II is beryllium, magnesium, calcium,
At least one of 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 each 0. .5 ≦ a
≦ 1.25, 0 ≦ x ≦ 1, 10 ⁻⁶ ≦ y ≦ 2 × 1
0 ⁻¹ , and 0 <z ≦ 5 × 10 ⁻¹ ], the phosphor represented by the composition formula: M ^III described in JP-A-58-69281.
OX: xCe [However, M ^III is Pr, Nd, Pm, S
m, Eu, Tb, Dy, Ho, Er, Tm, Yb, and at least one trivalent metal selected from the group consisting of Bi, and X is one or both of Cl and Br, x is 0 <x <0.1], a phosphor represented by the composition formula: Ba described in JP-A-58-206678.
_1-x M _{x / 2} L _{x / 2} FX: yEu ²⁺ [where 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, G
d, Tb, Dy, Ho, Er, Tm, Yb, Lu, A
represents at least one trivalent metal selected from the group consisting of 1, Ga, In, and Tl; X represents Cl, Br,
And at least one halogen selected from the group consisting of I and I; and x is 10 ⁻² ≦ x ≦ 0.5, y
Is 0 <y ≦ 0.1], a phosphor represented by the composition formula: BaF described in JP-A-59-27980.
X · xA: yEu ²⁺ [wherein X is at least one halogen selected from the group consisting of Cl, 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: BaF described in JP-A-59-47289.
X.xA: yEu ²⁺ [wherein X is at least one halogen selected from the group consisting of Cl, Br, and I; A is hexafluorosilicic acid, hexafluorotitanic acid, and hexafluorozirconic acid; A calcined product of at least one compound selected from the group of hexafluoro compounds consisting of salts of divalent or divalent metals;
Then, x is 10 ⁻⁶ ≦ x ≦ 0.1, y is 0 <y ≦ 0.
1. The phosphor represented by the composition formula [1], BaF described in JP-A-59-56479.
X · xNaX ′: aEu ²⁺ [where X and X ′ are
Is at least one of Cl, Br, and I, respectively, and x and a are 0 <x2 and 0, respectively.
A phosphor represented by the composition formula of <a ≦ 0.2], M ^II F described in JP-A-59-56480.
X · xNaX ′: yEu ²⁺ : zA [where M ^II is
Is at least one alkaline earth metal selected from the group consisting of Ba, Sr, and Ca; X and X ′ are
Each is at least one halogen selected from the group consisting of Cl, Br, and I; A is V, Cr, M
at least one transition metal selected from n, Fe, Co, and Ni; and x is 0 <z ≦ 2 and y is 0.
<Y ≦ 0.2, and Z is 0 <z ≦ 10 ⁻² ], the phosphor represented by the composition formula: M ^II F described in JP-A-59-75200.
X ・ aM ^I X '・ bM' ^II X " ₂・ cM ^III X ₃・ x
A: 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 from the group consisting of Li, Na, K, Rb, and Cs. is at least one alkali metal selected; M ^'II is at least one trivalent metal selected from the group consisting of be and Mg; M ^III is a
is at least one trivalent metal selected from the group consisting of 1, Ga, In, and Tl: A is a metal oxide; X is at least one halogen selected from the group consisting of Cl, Br, and I X ', X ", and X are 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 the composition formula: M ^II X ₂ · aM ^II described in Japanese Patent Application No. 58-193161 filed by the present applicant. 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 at least selected from the group consisting of Cl, Br and I; A kind of halogen and X ≠ X ′; and a is 0.1 ≦ a ≦ 10.0 and x is 0 <x ≦
Phosphor represented by a composition formula of which is 0.2, the Applicant M ^II FX ^· aM 1 X are described in Japanese Patent Application No. Sho 58-208727 Pat by ': ^{xEu 2+} [However, M ^II is Is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; M ¹ is R
X is at least one alkali metal selected from the group consisting of b and Cs; X is at least one halogen 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 respectively 0 ≦ a ≦ 4.0 and 0 <x ≦ 0.2]. Phosphors, Japanese Patent Application No. 60- (April 2, 1985)
Japanese application) M ¹ X: xBi described in the specification (where M ¹ 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) At least one halogen; and x is a numerical value in the range of 0 <x ≦ 0.2], and the like.

Further, in the M ^II X ₂ · aM ^II X ′ ₂ : xEu ²⁺ phosphor described in the above-mentioned Japanese Patent Application No. 58-193161, the following additives are included in the M ^II X ₂ · aM ^II. X '
_{2 It} may be contained in the following ratio per 1 mol.

BM ¹ X ″ (where M ¹ is Rb and Cs described in Japanese Patent Application No. 59-22169 by the present applicant).
Which is at least one alkali metal selected from the group consisting of, X ″ is at least one halogen selected from the group consisting of F, Cl, Br and I, and b is 0 <b ≦ 10.0) ; are described in Japanese Patent Application No. Sho 59-77225 Pat bKX "· cMgX ₂ · dM
^III X _'3 (however, 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
at least one halogen selected from the group consisting of 1, Br and I, and b, c and d are 0 ≦ b ≦ 2.0, 0 ≦ c ≦ 2.0 and 0 ≦ d ≦ 2.0, respectively.
And 2 × 10 ⁻⁵ ≦ b + c + d); yB described in Japanese Patent Application No. 59-84356.
(However, y is 2 × 10 ⁻⁴ ≦ y ≦ 2 × 10 ⁻¹ ); bA described in Japanese Patent Application No. 59-84358 (where A is SiO ₂ and P ₂ O _5). Which is at least one oxide selected from the group consisting of: and b is 10 ⁻⁴ ≦ b ≦ 2 × 10 ⁻¹ );
-240452, bSiO (where b is 0 <b≤3 × 10 ^-2 );
BSnX ″ ₂ described in US Pat.
(Where X ″ is at least one halogen selected from the group consisting of F, Cl, Br and I, and b
Is 0 <b ≦ 10 ⁻³ );
0-No. [Application April 11, 1985 (2)] Description of bCsX ″ · cSnX ₂ (however,
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 0 <b ≦ 10.0 and 10 ⁻⁶ ≦ c ≦ 2 × 10 ⁻² respectively); and Japanese Patent Application No. 60- [Applied April 11, 1985] by the present applicant. (4)] bCsX ″ · yLn described in the specification
³⁺ (where X ″ is at least one halogen selected from the group consisting of F, Cl, Br and I, and Ln
Is Sc, Y, Ce, Pr, Nd, Sm, Gd, Tb, D
at least one rare earth element selected from the group consisting of y, Ho, Er, Tm, Yb and Lu, and b
And y are 0 <b ≦ 10.0 and 10 ⁻⁶ , respectively.
≦ 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 when irradiated with excitation light after irradiation with radiation,
Any phosphor may be used as long as it exhibits stimulated emission.

The excitation light of the binder of the phosphor layer is a protein such as gelatin, a polysaccharide such as dextran, or a natural polymer substance such as gum arabic; and polyvinyl butyral, polyvinyl acetate, vitrocellulose, ethyl cellulose, vinylidene chloride.・ Vinyl chloride copolymer,
Examples thereof include binders represented by synthetic polymer substances such as polyalkyl (meth) acrylate, vinyl chloride / vinyl acetate copolymer, polyurethane, cellulose acetate butyrate, polyvinyl alcohol, and linear polyester. 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 a suitable 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 solution varies depending on the characteristics of the intended radiation image conversion panel, the kind of the 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).

The 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 plasticizers may be mixed. Examples of dispersants used for such purpose include:
Examples thereof include phthalic acid, stearic acid, caproic acid and lipophilic surfactants. Examples of plasticizers include phosphoric acid esters such as triphenyl phosphate, tricresyl phosphate, diphenyl phosphate; phthalic acid esters such as diethyl phthalate and dimethoxyethyl phthalate; ethyl phthalyl glycolate, butyl phthalyl butyl glycolate, etc. And a polyester of polyethylene glycol and an aliphatic dibasic acid, such as a polyester of triethylene glycol and adipic acid, a polyester of diethylene glycol and succinic acid, and the like.

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 phosphor layer on the support. The layer thickness of the phosphor layer is the characteristics of the intended radiation image conversion panel,
The thickness is usually 20 μm to 1 mm, although it varies depending on the type of phosphor, the mixing ratio of the binder and the phosphor, and the like. However, this layer thickness is preferably 50 to 500 μm.

Note that the phosphor layer does not necessarily have to be formed by directly applying the coating liquid on the support as described above.For example, the coating liquid is separately applied on a sheet such as a glass plate, a metal plate, or a plastic sheet and dried. After forming the phosphor layer by doing so, the support and the phosphor layer may be joined by pressing this on the support or using an adhesive or the like.

Next, a transparent protective film is provided on the surface of the phosphor layer opposite to the side in contact with the support for the purpose of physically and chemically protecting the phosphor layer.

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 high-molecular substance in a suitable solvent is applied to the surface of the phosphor layer. Alternatively, it can also be formed by a method of adhering a transparent thin film separately formed from polyethylene terephthalate, polyethylene, polyvinylidene chloride, polyamide or the like to the surface of the phosphor layer with an appropriate adhesive. The thickness of the transparent protective film thus formed is
It is preferably about 3 to 20 μm.

On this transparent protective film, a damage prevention film, which is a characteristic requirement of the present invention, is provided.

In the radiation image storage panel of the present invention, the damage prevention film is formed by using at least one compound selected from the group consisting of inorganic nitrides, inorganic carbides, inorganic oxides and inorganic fluorides. Specifically, nitrides such as BN and Si ₃ N ₄ ; carbides such as SiC, TiC and WC; MgO and Ca
Examples thereof include oxides such as O and B ₂ O ₃ ; fluorides such as BaF ₂ . All of these compounds can increase the surface hardness when formed as a thin film on the protective film. Of the above compounds, nitrides and carbides are particularly preferred.

However, the inorganic compound used in the present invention is not limited to the above compounds, and any inorganic nitride, inorganic carbide, inorganic oxide or inorganic fluoride may be used as long as it can prevent damage to the surface of the protective film. It may be. From the viewpoint of sensitivity, it is preferable that the substance has a high transparency to radiation such as X-rays and electromagnetic waves (excitation light) in the visible to infrared region.

The damage prevention film can be provided by forming a thin film made of the above-mentioned inorganic compound on the surface of the protective film by a method such as vacuum deposition or sputtering. The thickness of the damage prevention film is generally in the range of 500 to 20,000 Å (however, 1 / wavelength of excitation light in the range of 400 to 900 nm).
An odd multiple of 4, that is, nλ / 4 = 1, 3, 5, ~~~~~
˜: λ = excitation light wavelength, except for the film thickness corresponding to the optical film thickness).

The present invention, by providing the damage prevention film on the protective film side surface of the radiation image conversion panel as described above, significantly prevents the occurrence of damage such as scratches on the panel surface on the excitation light irradiation side, and As a result, it is possible to prevent deterioration of the image quality of the image obtained.

The radiation image conversion panel of the present invention is disclosed in JP-A-55-1.
63500, JP-A-57-96300 and the like, may be colored with a colorant,
By this coloring, the sharpness of the obtained image can be improved. Further, in the radiation image storage panel of the present invention, white powder may be dispersed in the phosphor layer for the same purpose as described in JP-A-55-146447.

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

[Example] 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 nitrocellulose having a nitrification degree of 11.5% was further added. A dispersion liquid containing the phosphor in a dispersed state was prepared. 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. Is 1:10, viscosity is 25-35P
A coating liquid of S (25 ° C.) was prepared. Next, the coating liquid was uniformly applied onto a titanium dioxide-kneaded polyethylene terephthalate sheet (support, thickness: 250 μm) placed horizontally on a glass plate using a doctor blade. After the application, the support on which the coating film was formed was placed in a dryer, and the temperature inside the dryer was gradually raised 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.

A transparent protective film is formed by placing a transparent film of polyethylene terephthalate (thickness: 12 μm, with a polyester adhesive) on this phosphor layer with the adhesive layer side facing down did.

Then, on this transparent protective film, titanium carbide (TiC)
Was deposited by sputtering to a thickness of about 2,000Å to form a damage prevention film.

In this way, a radiation image conversion panel composed of the support, the phosphor layer, the transparent protective film and the damage prevention film was produced.

[Comparative Example] In the example, by performing the same operation as the method of the example except that the damage prevention film is not provided on the protective film,
A radiation image conversion panel composed of a support, a phosphor layer and a transparent protective film was produced.

[Evaluation of Radiation Image Conversion Panel] A small piece of polyethylene terephthalate sheet, which is the same material as the support on the back surface of the panel, is placed on the surface (the surface of the damage prevention film or the surface of the protection film) of the protection film of each radiation image conversion panel, and sliding The test was conducted.

As a result, it was confirmed that in the radiation image storage panel of the present invention (Example), the number of scratches on the surface of the protective film was significantly reduced as compared with the conventional radiation image storage panel (Comparative Example).

Claims (2)

[Claims] 1. A radiation image conversion panel having a support, a phosphor layer containing a stimulable phosphor and a protective film in this order, wherein an inorganic nitride, an inorganic carbide or an inorganic material is provided on the protective film side surface of the panel. It is composed of at least one compound selected from the group consisting of oxides and inorganic fluorides, and has a film thickness of 500.
~ 20,000 Angstroms (however 400-90
The radiation image conversion panel is provided with a damage prevention film (excluding a film thickness corresponding to an optical film thickness corresponding to an odd multiple of 1/4 of the wavelength of the excitation light in the range of 0 nm). 2. The radiation image storage panel according to claim 1, wherein the damage prevention film comprises at least one compound selected from the group consisting of inorganic nitrides and inorganic carbides.