JPH02276999A - Radiation image converting panel and production thereof - Google Patents

Abstract

PURPOSE:To obtain the radiation image converting panel which has a high resistance to a temp. change and physical impact and does not generate unequalness in image quality by providing a strain relieving layer consisting of a thermoplastic resin between a phosphor layer and a base. CONSTITUTION:The phosphor layer consists of the flocks of stimulable phosphors. The stimulable phosphors are the phosphors which indicate the stimulable light in the wavelength range of 300 to 500nm by the stimulating light having the wavelength ranging 400 to 900nm and are exemplified by, for example, BaSO4, SrSO4:AX, etc. The thermoplastic resin is exemplified by, for example, a styrene system, polyolefin system, etc. and has adequately <=10kgf/mm<2> Young's modulus. The strain relieving layer in common use as an adhesive layer is formed by applying a coating liquid for forming the strain relieving layer in common use as the adhesive layer on a base, drying the coating, placing the phosphor film consisting of the flocs of the phosphors thereon and drying the same by a vacuum, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [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 a method for manufacturing the same.

[Technical Background of the Invention and Prior Art 1 As an alternative to conventional radiography, there is a radiation image conversion method using a stimulable phosphor as described in, for example, Japanese Patent Application Laid-Open No. 55-12145. Are known.

This method uses a radiation image conversion panel (also called a stimulable phosphor sheet) containing a stimulable phosphor, and converts the radiation transmitted through the subject or emitted from the subject into the brightness of the panel. The stimulable phosphor is absorbed by the stimulable phosphor, and then the stimulable phosphor is excited with 71i magnetic waves (excitation light) such as visible light and infrared rays in a time series, so that the stimulable phosphor is accumulated in the stimulable phosphor. The radiation energy is emitted as fluorescence (stimulated luminescence light), this fluorescence is read photoelectrically to obtain an electrical signal, and the radiation image of the subject or subject is reproduced as a visible image based on the electrical signal obtained. It is something.

On the other hand, the panel that has been read is prepared for the first photographing after the recorded image is erased. That is, the radiation image conversion panel is used repeatedly.

According to this radiation image conversion method, it is possible to obtain a radiation image with a rich amount of information with a much lower exposure dose compared to the conventional radiography method that uses a combination of a radiographic film and an intensifying screen. It has the advantage of being possible. Furthermore, in contrast to conventional radiography, which consumes radiographic film for each imaging session, the above-mentioned radiographic image conversion method uses the radiographic image conversion panel repeatedly, which is advantageous in terms of resource conservation and economic efficiency. It is.

As mentioned above, the radiation image conversion method using stimulable phosphors can obtain radiographic images rich in information with a small exposure dose, so it is especially suitable for direct use such as X-ray photography for medical diagnosis. It has extremely high utility value in medical radiography.

The radiation image conversion panel used in the radiation image conversion method described above has a basic structure consisting of a support and a stimulable phosphor layer provided on one side of the support. Note that if the phosphor layer is self-supporting, a support is not necessarily required, and the surface of the stimulable phosphor layer opposite to the support (the side not attached to the support) Generally, a transparent protective film is provided on the surface of the phosphor layer to protect the phosphor layer from chemical alteration or physical impact.

A stimulable phosphor layer generally consists of a stimulable phosphor and a binder that contains and supports the stimulable phosphor in a dispersed state.The stimulable phosphor absorbs radiation such as X-rays and then absorbs excitation light. It has the property of exhibiting stimulated luminescence when irradiated. 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 subject is displayed on the panel. It is formed as an image of accumulated energy. This accumulated image can be emitted as stimulated luminescence light by irradiating the excitation light, and by photoelectrically reading this stimulated luminescence light and converting it into an electrical signal, the accumulated a image of radiation energy can be imaged. It becomes possible to convert into

The radiation image conversion method is a very advantageous image forming method as mentioned above, but the radiation image conversion panel used in this method is similar to the intensifying screen used in conventional radiography.
It is desired to provide an image with high sensitivity and good image quality (sharpness, 1 graininess, etc.). Furthermore, since the radiation image conversion panel is used repeatedly as mentioned above, it must be resistant to physical shocks and changes in the environment (temperature, humidity, etc.) to ensure the reliability of the image data obtained. It is also necessary to ensure safety, improve economic efficiency, and ease of handling.

The sensitivity of a radiation image conversion panel basically depends on the total amount of stimulated luminescence of the stimulable phosphors contained in the panel, and this total amount of luminescence depends not only on the luminance of the phosphors themselves but also on the fluorescence It also varies depending on the content of phosphor in the body layer. A high content of phosphor also means high absorption of radiation such as X-rays, resulting in higher sensitivity and at the same time improved image quality (particularly graininess). On the other hand, if the phosphor content in the phosphor layer is constant,
The denser the phosphor particles are packed, the thinner the layer thickness can be, so the spread of excitation light due to scattering can be reduced, and relatively high sharpness can be obtained.

Up until now, the phosphor layer has generally been formed by preparing a coating solution in which stimulable phosphor particles are dispersed in a binder solution, and applying this coating solution using a conventional coating method such as a doctor blade or roll coater. This is done by applying the coating onto a support or another sheet and then drying it. In the radiation image storage panel formed in this way, which has a phosphor layer in which phosphor particles are dispersed in a binder, there are limits to the content and packing density of the phosphor in the phosphor layer. It was difficult to obtain sufficiently satisfactory sensitivity and image quality.

On the other hand, 1'1?, where the phosphor particles are not dispersed in the binder, but the phosphor forms aggregates? Photolayers are also known.

As a method for forming a phosphor layer consisting only of a stimulable phosphor without containing a binder, for example, US Pat.
59,527, there is a description that the storage medium is composed of a phosphor obtained by the Hontopress method, and JP-A-617-3100 describes that a phosphor layer is formed using a baking method. A method for forming the is described.

The present applicant has proposed a radiation image conversion panel having a support and a phosphor layer made of a stimulable phosphor provided on the support, in which the phosphor layer is sintered. We have already filed a patent application for a radiation image conversion panel, which is characterized by being made of human body, and a method for manufacturing the same. (
Japanese Unexamined Patent Publication No. 19600/1983, Patent Application No. 1676/1983
(See Specification No. 30) Furthermore, the present applicant has proposed that the phosphor layer is made of a sintered stimulable phosphor or a vapor-deposited stimulable phosphor, and that the phosphor layer is made of a polymer. A patent application has already been filed for a radiation image storage panel characterized by being impregnated with a substance and a method for manufacturing the same (Japanese Patent Application No. 1983-96803).

A phosphor layer made of aggregates of these stimulable phosphors can be manufactured by a sintering method, a vapor deposition method, etc., and if it contains a polymeric substance, it can be manufactured by a sintering method, a vapor deposition method, etc.
It can be manufactured by once creating a phosphor layer that does not contain any polymeric substance and then impregnating the phosphor layer with the polymeric substance.

In these phosphor layers, the phosphor particles are not dispersed but aggregated. In other words, these phosphor layers either do not contain any polymeric material, or even if they do contain the polymeric material, the polymeric material is impregnated into the phosphor layer, so the polymeric material is an aggregate of phosphor. It exists in the gaps of the phosphor (for example, in the case of a sintered phosphor layer, in the grain boundaries and/or pores of the phosphor).

By the way, as described above, it is desired that the radiation image conversion panel not only have high sensitivity and high image quality, but also be resistant to physical shocks and changes in the environment (temperature, humidity, etc.). In particular, radiation image storage panels that have a phosphor layer consisting only of aggregates of stimulable phosphor are affected by changes in temperature.
Distortion occurs due to the difference in coefficient of thermal expansion between the phosphor layer and the support, and the stress caused by the distortion tends to cause cracks in the phosphor layer and deformation of the support. Furthermore, with respect to physical impact, for example, the impact applied to the support due to dropping is transmitted to the phosphor layer, which has the disadvantage that the phosphor layer is likely to crack.

Although these drawbacks can be improved to a large extent by impregnating the phosphor layer with a polymeric substance as described above, this is not yet fully satisfactory.

In order to solve this problem, the applicant of the present application has already applied for a radiation image conversion panel in which a strain relaxation layer is provided between the phosphor layer and the support (see the specification of Japanese Patent Application No. 6326322). Although the above-mentioned problems can be solved in a radiation image storage panel provided with such a strain-relaxing layer, it is a relatively difficult task to adhere the strain-relaxing layer to the phosphor layer and the support. Another drawback is that air bubbles generated within the strain relaxation layer cause uneven image quality.

[Summary of the Invention] An object of the present invention is to provide a radiation image conversion panel that is highly resistant to temperature changes and physical shocks and does not cause unevenness in image quality, and a method for manufacturing the same. It is something. Another object of the present invention is to provide a method for manufacturing a radiation image storage panel that allows a strain relaxation layer to be adhered to a phosphor layer and a support with relative ease.

The above object is to provide a radiation image conversion panel of the present invention having a support and a phosphor layer formed of an aggregate of stimulable phosphor provided on the support. A radiation image conversion panel characterized in that a strain relaxation layer made of a thermoplastic resin is provided between the panel and the support, and a resin layer made of a thermoplastic resin and an aggregate of a stimulable phosphor on a support. This is achieved by a method for producing a radiation image conversion panel, which is characterized in that a planting material is prepared in which phosphor films and phosphor films are arranged in this order, and the planting material is fused and integrated by heating the planting material under vacuum. I can do it.

The thermoplastic resin used in the present invention has a Young's modulus of 1.
It is preferable that it is 0 kgf/mm2 or less.

In the present invention, the strain relaxation layer is a layer that absorbs misalignment and strain caused by temperature changes due to the difference in thermal expansion coefficient between the support and the stimulable phosphor layer. A layer that acts to reduce the stress that is applied to

The radiation image storage panel of the present invention has a strain relaxation layer made of a thermoplastic resin, preferably having a Young's modulus of 10 kgf/mm2.
It has a strain relaxation layer made of the following thermoplastic resin. Further, the method for manufacturing the radiation m-image conversion panel of the present invention is as follows:
The strain relaxation layer made of this thermoplastic resin is provided between the phosphor layer and the support by fusion under vacuum.

/8 Town Plastic resin has the property of becoming fluid when heated. Therefore, when a strain relaxation layer made of a thermoplastic resin is provided between the support and the phosphor layer, if it is heated under vacuum, the air bubbles generated inside the layer will be removed by the heat, since the thermoplastic resin has fluidity. The strain relaxation layer made of thermoplastic resin moves through the flexible resin and exits to the outside under reduced pressure, and because of this fluidity, the strain relaxation layer made of thermoplastic resin can be easily adhered to the support and the phosphor layer. can.

Preferred embodiments of the present invention are shown below.

(1) A radiation image conversion panel characterized in that the phosphor layer is made of sintered stimulable phosphor.

(2) A radiation image conversion panel characterized in that the phosphor layer is made of a stimulable phosphor on which the phosphor layer is vapor-deposited.

(3) A radiation image conversion panel characterized in that the phosphor layer is impregnated with a polymeric substance.

(4) A radiation image conversion panel characterized in that the strain relaxation layer also serves as an adhesive layer.

(5) The Young's modulus of the thermoplastic resin is 10101 (7
A radiation image conversion panel characterized in that the size is less than mm2.

(6) A method for producing a radiation image storage panel, which comprises forming a resin layer made of the thermoplastic resin on a support in advance, and then laminating the stimulable phosphor film thereon to prepare a laminate.

(7) A method for producing a radiation image conversion panel, wherein the phosphor layer is made of a sintered stimulable phosphor.

(8) A method for producing a radiation image conversion panel, characterized in that the phosphor layer is made of a stimulable phosphor on which the phosphor layer is vapor-deposited.

(9) A method for producing a radiation image storage panel, characterized in that the phosphor layer h is impregnated with a polymeric substance.

(10) A method for producing a radiation image conversion panel, wherein the strain relaxation layer also serves as an adhesive layer.

(11) The Young's modulus of the thermoplastic resin is lOkg f
A method for producing a radiation image conversion panel having four characteristics: / mm 2 or less.

[Structure of the Invention] In the radiation image storage panel of the present invention, a strain relaxation layer made of a thermoplastic resin is generally provided on a support via an adhesive layer, and a strain relief layer made of a thermoplastic resin is further provided on the side opposite to the support of the strain relief layer. ,
A preferred embodiment of the present invention has a configuration in which a phosphor layer is provided via an adhesive layer! Model No. 51 is a panel in which the strain relaxation layer also serves as an adhesive layer, but in this case there is no adhesive layer between the support and the strain relaxation layer and no adhesive layer between the strain relaxation layer and the phosphor layer. 1. The phosphor layer is supported via the strain relaxation layer/adhesive layer. It is submerged on the ν body.

The radiation image conversion panel of the present invention can be manufactured by the method for manufacturing the radiation image conversion panel of the present invention described below.

First, a phosphor layer (phosphor film) made of aggregates of stimulable phosphors will be described.

As mentioned above, a stimulable phosphor is a phosphor that exhibits stimulated luminescence when irradiated with radiation and then irradiated with excitation light.
From a practical standpoint, it is desirable that the phosphor be a phosphor that exhibits stimulated luminescence in the wavelength range of 300 to 500 nm when excited by excitation light in the wavelength range of 400 to 900 nm. As an example of a fluorescent phosphor, B described in Japanese Patent Application Laid-Open No. 48-80487 is
asOR: AX and S described in JP-A No. 48-80489 rsO4: Phosphor represented by AX, Li2 described in JP-A-53-39277
B4O+: Cu, Ag, Li2 described in JP-A-54-47883
O.(B202)X: Cu and Li2O'(B20y
)x: Cu, Ag, U.S. Patent No. 3,859,5
SrS described in specification No. 27: Ce, Sm, S
rS:Eu.

Sm, Th02:Er, and La2O2S:Eu,
Sm, ZnS described in JP-A-55-12142
:Cu, Pb, BaO*xAu20. :Eu (however,
0.8≦X≦io), and Mtomi0axSi02:
A (However, Ml is MgCa, Sr, Zn, Cd, or Ba, and A is Ce, Tb, Eu, Tm, Pb,
Tl, Bi or Mn, and X is 0.5≦X≦2.
5), described in Japanese Patent Application Laid-Open No. 55-12143 (B
a+−x−y, Mgx, Cay
) F X : a E u ``'' (However, X is at least one of C1 and Br,
0-"≦a≦5X10-2), LnO described in JP-A-55-12144
X: xA (Ln is at least one of La, YGd, 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), which is described in JP-A-55-12145 (Ba
l-H, M2°x) FX:yA (However, M” is Mg
, Ca, S r, Zn, and Cd (7), X is at least one of C1, Br, and I, A is Eu, Tb, Ce, Tm, Dy, P
At least one of r, Ho, Nd, Yb, and Er, and X is.

O≦X≦0.6, y is 0≦y≦0.2) Ba described in JP-A-55-843897
FX: Phosphor expressed by xCe, yA JP-A-1983-
MIFxlIxA described in Publication No. 160078
:yLn[However, Mll is Ba, Ca, Sr, Mg,
At least one of Zn and Cd (7), A is B
eO, MgO1CaO1SrO, Bad, ZnO, AJ
120. , Y2O1, La2O3, In2O3, Si
o2, TiO2, ZrO2, Gem2, SnO2,
Nb2O6, Ta2O, and T h O217), Ln is Eu, Tb, Ce, Tm,
Dy, Pr, Ho, Nd, Yb, Er, Sm,
and at least one of Gd, X is C! ;LBr
, and I, and X and y are respectively 5 X I O-'≦X≦0.5 and Okuy≦0.2]; It is described in Publication No. 56-116777 (B
a, -x, M''x)F211aBaX2:yE
u, zA[However, M[represents helium, magnesium,
at least one of calcium, strontium, zinc, and cadmium;
and Z are respectively 0.5≦a≦1.25.0≦X≦1
10-'≦y≦2XIO-', and 0<z≦10-2
A phosphor represented by the composition formula, JP-A-57-2
It is described in the publication No. 3673 (Bat-x, M”
x) F2a aBaX2: yEu, zB [However, M
ll 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 2 are each 0.5≦
a≦1.25, O≦X≦1, 10-6≦y≦2×1O
-1, and 0<z≦2
,-,1,M"x)F2 ・nReX2:yEu,z
A [However, Ml 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 2 are each 0.
5≦a≦1.25.0≦X≦1.10-6≦y≦2×1
0-', and O<2≦5×lO-";
OX: xCe [However, M is Pr, NdPm,
Sm, Eu, Tb, Dy, Ho,
At least one trivalent metal selected from the group consisting of Er, Tm, Yb, and Bi, and X is C1 and Br.
one or both of these, and X is O
A phosphor represented by the composition formula <x<0.1], B described in JP-A No. 58-206678
a+-xMx/2Lx/2Fx:
y E u 2° [However, M is Li, Na, R
b, and at least one alkali metal selected from the group consisting of Cs: L is Sc, Y, La, Ce;
, Pr, Nd, Pm, Sm, Gd, Tb, Dy.

Ho Er, Tm, Yb, Lu, An, Ga, In,
and Tl; X represents at least one halogen selected from the group consisting of C1, Br, and I; and X represents 10-2≦X≦0. 5, y is o<y≦0.1] A phosphor represented by the composition formula: BaF described in JP-A No. 59-27980
Xa xA: yEu” [However, X is C1, B
r, and at least one kind of halogen selected from the group consisting of I; A is a fired product of a tetrafluoroboric acid compound; and X is 10-6≦X≦o, t, y
xM3, which is described in JP-A-59-38278, is a phosphor represented by the composition formula: o<y≦0,1]
(PO4)2・NX2:yA, M3(PO4h:!7A
and nReX3-rnAX'2: xEu, nReX
3-mAX'z: xE u , ySm, MI Xo
aM"X'+* bMIII
At least one halogen selected from the group consisting of C1, Br, and I; A is hexafluorosilicic acid, hexafluorotitanic acid, and hexafluorozirconic acid consisting of a monovalent or divalent fully divalent salt; It is a fired product of at least one kind of compound selected from the group of compounds; and X is 10-6≦X≦o, i, y
is o<y≦0.1], a Ba phosphor described in JP-A No. 59-56479
FXa xNaX': aEu"" [However, X and
o is at least one of C1, Br, and I, and X and a are 0<x≦2 and 0<a≦0.2, respectively]; M” described in the Publication No. 59-56480
FX* xNaX':yE u'': zA [However, M'' is at least one alkaline earth metal selected from the group consisting of Ba, Sr, and Ca; x and X' If, each C! ;L, Br, and I
At least one type (7) selected from the group consisting of halogen; A is V, Cr, Mn, FeCo, and N
is at least one transition metal selected from i; M” described in Japanese Unexamined Patent Publication No. 59-75200
FX* aM'X' * bM' ”Xo2 AcMX
"°3*xA:yEu" [However, MI is Ba, Sr,
and at least one alkaline earth metal selected from the group consisting of Ca; MI is Li, Na, Rb,
and CS; M″ is at least one divalent metal selected from the group consisting of Be and Mg; M is A
at least one trivalent metal selected from the group consisting of n, Ga, In, and Tl; A is a metal oxide; X is at least one halogen selected from the group consisting of C1, Br, and I; Yes, x', xo, oyobi
″′ is at least one kind of halogen selected from the group consisting of F, CM, Br, and ■; and a is 0
≦a≦2, b is 0≦b≦1O-2, C is O≦C≦1O-
A phosphor represented by the composition formula: 2 katsu a + b + c≧10-'ffi; -M”X described in Publication No. 84381
2 * aM'X' 2 : xEu" [However, M
ll is at least one alkaline earth metal selected from the group consisting of lea, Sr and Ca;
゛ is at least one kind of halogen selected from the group consisting of C1, Br, and I, and X≠X°; and a is 0.1≦a≦10.0. A stimulable phosphor represented by the composition formula where x is 0<x≦0.2;
FX* aM'X': xEu'' [where Ml is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; Ml is Rh and C
at least one alkali metal selected from the group consisting of s; X is at least one halogen selected from the group consisting of 0, Br and I; xo is F, C1
, Br, and at least one halogen selected from the group consisting of
≦4.0 and O<x≦0.2] A stimulable phosphor represented by the composition formula:
X : xB i [ri? 'L, MI are at least one kind of alkali metal selected from the group consisting of Rb and C5; X is at least one kind of halogen selected from the group consisting of C1, Br and I: and X is 0
Examples include a stimulable phosphor represented by the composition formula <a numerical value in the range of x≦0.2].

In addition, the M"X2* aM"X' 2 :
It may be contained in the following proportions per 21 moles of M''X'.

bM described in JP-A-60-166379
'X'' (However, Ml is at least one alkali metal selected from the group consisting of Rb and Cs, and
is at least one kind of halogen selected from the group consisting of F, CM, Br and I, and b is o<b≦10
．． 0); bKX"a cMgX"2 * dM
"", (M" is Sc, Y, La, Gd and L
is at least one trivalent metal selected from the group consisting of u, and X", X" and X" are all F, C1, Br
and ■ at least one kind of halogen selected from the group consisting of
≦2.0.0≦C≦2゜0・0≦d≦2.0, and 2 X 10-'≦b+c+d); yB described in JP-A-60-228592 (However, y is 2X l O-'≦y≦2×10-")
; b described in Japanese Patent Application Laid-Open No. 60-228593
A (where A is at least one kind of oxide selected from the group consisting of 5iO7 and P2O5, and b is to-'≦b≦2X10-'); JP-A-61-1
bSin described in Publication No. 20883 (however,
b is o<b≦3X10-2); Old opening 1 eyebrow 61-1
bSnX''2 (where X'' is at least one kind of halogen selected from the group consisting of FCn, Br and I, and b is o<
b≦io−′); bCsX”・csnX”2 described in JP-A No. 61-235486 (where X” and X″ are each from the group consisting of F, C1, Br and I); at least one selected halogen, and b and C are each o<b≦10.0
and 10-6≦C≦2×10-2); and bCs described in JP-A-61-235487.
X”・y L n ” (X” is F, C1, Br
and I, and Ln is Sc, Y, Ce, Pr, Nd, Sm
, Gd, Tb, Dy, Ha, Er, Tm, Yb and L
is at least one rare earth element selected from the group consisting of u, and b and y are respectively o<b≦io,
o and 10-6≦y≦1.8XIO-').

Among the stimulable phosphors described above, divalent europium-activated alkaline earth metal halide phosphors and cerium-activated rare earth oxyhalide phosphors are particularly preferred because they exhibit high-intensity stimulated luminescence. However, the stimulable phosphor used in the present invention is not limited to the fireflies and photophores mentioned above, but any phosphor that exhibits stimulated luminescence when irradiated with radiation and then irradiated with excitation light. It can be anything.

The phosphor layer made of an aggregate of all-white stimulable phosphor can be provided by forming a phosphor film by, for example, the following sintering method and attaching it to the strain relaxation layer 1.

That is, in the case of the sintering method, the manufacturing process of the phosphor film consists of a step of molding a phosphor film-forming material containing a stimulable phosphor into a sheet shape, and a step of sintering this molded product.

In the process of forming the phosphor film forming material into a sheet shape,
As a material for forming a phosphor film, 211i! A powder consisting of particles of an i-exhaustive phosphor can be used.

Furthermore, a dispersion containing particles of the above-mentioned stimulable phosphor and a binder can also be used as the phosphor film forming material. In this case, the stimulable phosphor and binder are added to a suitable solvent and then thoroughly mixed to prepare a dispersion in which phosphor particles are uniformly dispersed in the binder solution.

As the binder, it is preferable to use a substance that has suitable properties in terms of dispersibility of the phosphor or dispersion during the sintering process. Examples of such materials include paraffin (e.g., carbon number: 16 to 40, melting point: 37.8 to 64.5
Wax (Natural waxes include: Candelilla wax, carnauba wax, rice wax, vegetable waxes such as Japanese wax, animal waxes such as beeswax, lanolin spermaceti, montan wax, otskelite, ceresin, etc.) Mineral Wankatsu 1 Synthetic waxes include: polyethylene wax, coal-based synthetic wax such as copolymer Tropsch wax, oil-based synthetic wax such as hydrogenated castor oil, fatty acid amide ketone); resin (polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethyl cellulose) , vinylidene chloride 1'
1! vinyl chloride copolymer, polyalkyl (meth)acrylate, vinyl chloride/vinyl acetate copolymer, polyurethane cellulose acetate butyrate, polyvinyl alcohol, linear polyester), and the like. Proteins such as gelatin, polysaccharides such as dextrose, or gum arabic can also be used.

Examples of solvents include lower alcohols such as methanol, ethanol, n-propanol, and n-butanol; 11! such as methylene chloride and ethylene chloride; Hydrocarbons containing elementary atoms; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters of lower fatty acids and lower alcohols such as methyl acetate, ethyl acetate, and butyl acetate; dioxane, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, etc. Ethers: and mixtures thereof may be mentioned.

- The mixing ratio of the binder and the stimulable phosphor in the dispersion described in F varies depending on the type of phosphor and the molding conditions and sintering conditions described below, but in general, the mixing ratio of the binder and the stimulable phosphor is selected from the range 1:l to 1:300 (weight ratio), and especially l:20 to 1:150 (weight ratio)
It is preferable to choose from the range.

Note that the dispersion liquid may contain additives such as a dispersant for improving the dispersibility of the phosphor. Examples of dispersants used for such purposes include phthalic acid, stearic acid, caproic acid, lipophilic surfactants, and the like.

Next, a powder made of phosphor particles or a dispersion containing phosphor particles and a binder prepared as described above is formed into a sheet.

When the material for forming the phosphor film is a powder, it is preferable to mold the material into a sheet by pushing the powder into a mold. A rectangular mold is usually used for molding. In addition, if the phosphor film forming material is a dispersion liquid, the usual coating method (for example, doctor blade, etc.)
It is preferable to apply the powder onto a suitable substrate and mold it into a sheet, or to mold it into a sheet by pouring it into a mold in the same way as the powdered material described above.

In the above molding process, compression treatment may be performed,
In particular, when the phosphor film forming material is a powder, compression treatment is performed. The compression treatment is performed, for example, by press molding, and is preferably performed by applying a pressure in the range of 1×10 2 to 1×10' kgf/Cm 2 . This makes it possible to further increase the relative density of the resulting phosphor layer.

Next, the sheet-shaped molded product obtained as described above is sintered.

Sintering is performed, for example, in a firing furnace such as an electric furnace. The sintering temperature and sintering time vary depending on the type of phosphor film forming material, the shape and condition of the sheet-shaped molded product, and the type of stimulable phosphor used therein, but generally the sintering temperature is 500℃ to 500℃. in the range of 1000°C, preferably 7
The temperature ranges from 00 to 950°C, and the sintering time preferably ranges from 0.5 to 6 hours. The sintering atmosphere is usually a neutral gas atmosphere such as a nitrogen gas atmosphere or an argon gas atmosphere, or a weakly reducing atmosphere such as a nitrogen gas atmosphere containing a small amount of hydrogen residue, or a carbon dioxide atmosphere containing -carbon oxide. be done.

If the sheet-like molded product is a powdered material made of a stimulable phosphor, sintering is directly performed under the above sintering conditions, but if the sheet-like molded product contains a stimulable phosphor and a binder, In the case of a dispersion liquid, the binder in the sheet-like molded product is heated in advance at a relatively low temperature ( After aeration at a temperature in the range of 100 to 450[deg.] C., it is preferable to sinter the sintered material under the sintering conditions described in -F. Due to the nature of the binder in this low temperature range, components other than the stimulable phosphor such as the binder have a concentration of 300 to 4
It volatilizes at around 00°C or becomes carbon dioxide and is easily removed. As a result, the obtained phosphor is 1N! 2 is composed only of phosphor. Time for low temperature dispersion is 0
．． Preferably, the time is in the range of 5 to 6 hours.

Note that the compression treatment may be performed before the sintering process as described above, but may also be performed during the sintering process. That is,
Sintering may be performed while performing compression treatment. This is particularly suitable when the sheet-like molded product is a powdered material consisting only of phosphor particles.

The relative density of the phosphor thus formed is generally 7
It is 0% or more. The grain boundary size of the phosphor is from 1 to 100
The thickness of the phosphor film varies depending on the characteristics of the intended radiation image conversion panel, but is usually in the range of 20 m to 1 mm, preferably 50 to 500 gm. is within the range of

A phosphor film in which the stimulable phosphor is an aggregate may be produced not only by the sintering method described above but also by a hot pressing method, a vapor deposition method, or the like.

The phosphor layer made of aggregates of stimulable phosphors of the radiation image storage panel of the present invention is not limited to only the aggregates of stimulable phosphors formed as described above. The layer may be impregnated with a polymeric substance.

The phosphor film formed in this way is used as a support, which will be described later.
Second, it is attached via a strain relaxation layer made of thermoplastic resin.

As thermoplastic resins, polystyrene thermoplastic resins,
Polyolefin thermoplastic resin, polyurethane thermoplastic resin, polyester thermoplastic resin, polyamide thermoplastic resin, 1.2-polybutadiene thermoplastic resin,
Ethylene-vinyl acetate thermoplastic resin, polyvinyl chloride thermoplastic resin, natural rubber thermoplastic resin, fluororubber thermoplastic resin, trans-polyisoprene thermoplastic resin, chlorinated polyethylene thermoplastic resin, Examples include polypropylene thermoplastic resins and polyether thermoplastic resins. Among these, Young's modulus is 1
Those having a value of 0 kg f / mm 2 or less are particularly preferably used in the present invention.

The method for manufacturing a radiation image conversion panel of the present invention includes disposing a resin film made of a thermoplastic resin such as "-2" on a support "2,"
The method is characterized in that the phosphor film obtained as described above is placed thereon, and this resin film is bonded between the support and the phosphor layer by vacuum fusion to form a strain relaxation layer. Further, in the radiation image storage panel of the present invention, it is preferable that the strain relaxation layer also serves as an adhesive layer.

The strain relaxation layer/adhesive layer can be provided between the support and the phosphor layer, for example, by the method described below.

A strain-relaxation layer/adhesive layer forming coating solution containing a thermoplastic resin dissolved in a suitable solvent is applied onto the support and allowed to dry to form a strain-relaxation layer/adhesive layer coating film (resin film). A phosphor film made of the above-mentioned phosphor aggregate is placed on this coating film (resin film) and heated under vacuum using a vacuum dryer or the like. The degree of vacuum at this time is 1O-1 to 10To
Generally, it is about rr. Further, the heating temperature is appropriately determined depending on the softening temperature or melting point of the thermoplastic resin used, but is generally 30 to 300°C.

By heating under vacuum, the strain relaxation layer/adhesive layer (resin film) made of thermoplastic resin is easily fused to the support and the phosphor layer, and air bubbles generated in the coating film are also released to the outside. Disappear.

As mentioned above, in addition to forming a resin layer of thermoplastic resin directly on the support by coating, a resin film of thermoplastic resin is formed in advance, and this is placed on the support. A laminate may be prepared by depositing a phosphor film.

When the phosphor layer is impregnated with a polymeric substance, the phosphor layer may be impregnated with the phosphor layer attached as described above on the strain relaxation layer/adhesive layer of the panel, or it may be impregnated with the phosphor layer on the panel as described above. It may be carried out in the state of a phosphor film before being attached.

Next, the support will be described.

The support used in the present invention can be arbitrarily selected from various materials known as supports for radiation image storage panels. Examples of such materials include cellulose acetate, polyester, polyethylene terephthalate,
plastic films such as polyamide, polyimide, triacetate, and polycarbonate, metal sheets such as aluminum foil and aluminum alloy foil, ceramic plates, metal plates, regular paper, baryta paper, resin coated paper, and titanium dioxide. Pigment paper containing pigments such as, sizing paper containing polyvinyl alcohol, etc. can be mentioned. A light-absorbing substance such as carbon blank may be kneaded into this support,
Alternatively, a light-reflecting substance such as titanium dioxide may be incorporated.

In addition, as a support, Young's modulus is 5X 103kgf/
Breaking strength is 5 x 10 kgf/mm2 for mm2 or more
It is preferable to use the above materials because it is possible to obtain a radiation image conversion panel that is highly resistant to external impacts. Such materials include carbon fiber laminates [Young's modulus: 2 x 10' kg f/mm
? , breaking strength: lX102kgf/mm2], aromatic nylon (aramid) laminate [Young's modulus + IXI 0
4 kgf/mm2 breaking strength: lXl0;' kgf
/mm2 ], jjj silicon oxide, +: m fiber laminate [
Young's modulus: lX104 kgf/mm2. Breaking strength:
lX102 kgf/mm? ] Thermit plate [Young's modulus: 4X104 kgf/mm2. Breaking strength: 2-4
X104kgf/mm2].

In known radiation image conversion panels, in order to improve the sensitivity or image quality (graininess, graininess) of the radiation image conversion panel, a light reflective layer made of a light reflective material such as titanium dioxide, or a carbon blank, etc. is used. The support used in the present invention can also be provided with a light-absorbing layer made of a light-absorbing substance. Of course, these layers may be made of thermoplastic resin and may also serve as the above-mentioned strain relaxation layer.

It is preferable that a transparent protective film be 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 can be made of, for example, a cellulose derivative such as cellulose acetate or nitrocellulose; It can be formed by applying a solution prepared by dissolving a transparent polymeric substance such as a molecular substance in a suitable solvent onto the phosphor layer. Alternatively, a plastic sheet made of polyethylene terephthalate, polyethylene, polyvinylidene chloride, polyamide, etc. or a protective film forming sheet such as a transparent glass plate is formed separately and adhered to the surface of the phosphor layer using an appropriate adhesive. It can also be formed by the following method. Further, the protective film can also be formed by vapor depositing or baking ceramics such as S i 0 2, glass, or organic substances on the surface of the phosphor layer. The IIQ thickness of the transparent protective film formed in this way is about 3 to 20
It is preferable to set it as gm.

Next, Examples and Comparative Examples of the present invention will be described.

However, this example does not limit the invention.

[Example 1] Powdered divalent europium activated barium fluoride bromide phosphor particles (BaFBr2O.001Eu'')
) and an acrylic resin to prepare a dispersion containing phosphor particles in a dispersed state 5E.6 Next, this dispersion was thoroughly stirred and mixed using a propeller mixer. The phosphor particles are uniformly dispersed, and the mixing ratio of the binder and the phosphor particles is 1:20 (weight ratio).
A coating liquid having a viscosity of 35 to 50 ps (25° C.) was prepared.

Next, the obtained coating liquid was placed horizontally on a Teflon sheet)
It was applied evenly using a doctor blade. After coating, the Teflon sheet with the coated film is placed in a dryer, and the temperature inside the dryer is adjusted from 25℃ to 100℃.
The coating film was dried by gradually raising the temperature to . After drying, coating 119 (film thickness: 300 ILm) was peeled off from the Teflon sheet, placed on a quartz plate, placed in an electric furnace, and heated in an air atmosphere for 4 hours.
The binder was volatilized at a temperature of 00° C. for 1 hour, and sintering was further performed at a temperature of 800° C. for 2 hours in a nitrogen gas atmosphere. The obtained sheet-shaped sintered product was taken out from the electric furnace and cooled to form a phosphor layer having a layer thickness of 250 gm and consisting only of phosphor.

On the other hand, in 45 g of methyl ethyl ketone, a thermoplastic resin (manufactured by Toyobo ■, unsaturated polyester resin Vylon 300) was added.
15g of the strain relaxation layer/adhesive layer forming coating solution was applied to an aluminum metal plate (support, size: 250 x 2
00 mm, thickness = 1 mm) and dried to form a strain relaxation layer/adhesive layer coating film (thickness: 250 mm). The above phosphor layer is placed on top of this, and a sufficiently large area is covered with the support via an aluminum spacer (thickness: 1.5 mm) and the same thermoplastic resin (thickness: 6 mm) as above. There was garbage between the two glass plates held. this,
It was placed in a vacuum dryer (DP-41 manufactured by Yamato Kagaku Corporation) and vacuum heated at about 10 Torr and about 150° C. for 120 minutes to produce an uninvented radiation image conversion panel.

[Example 2] In Example 1, a polystyrene thermoplastic resin (manufactured by Japan Synthetic Rubber Co., Ltd., JS
RTR-2000) 12 g to prepare a strain relaxation layer/adhesive layer forming coating solution, and the heating temperature during adhesion of the strain relaxation layer and phosphor layer to approximately 120°C.
A radiation image conversion panel of the present invention was manufactured in the same manner as in Example 1 except for the following.

[Comparative Example 1] A 5 mm square polyethylene terephthalate sheet (J!i size: 250 m
) was glued. A phosphor layer similar to that in Example 1 was placed on top of this, silicone rubber (KE103 manufactured by Shin-Etsu Silicone mixed with a specified curing agent) was poured between the support and the phosphor layer, and cured at room temperature. An image conversion panel was manufactured.

Evaluation of radiation image conversion panels The radiation image conversion panels of Example 1 and Comparative Example 1 obtained as described above were irradiated with X-rays at a tube voltage of 80 KVp, and then scanned with He-Ne laser light (632.8 nm). The phosphor was excited, and the stimulated luminescence emitted from the phosphor layer was received and converted into an electrical signal, which was then output again as an image on film.

When the images from both panels were compared, unevenness was observed in the image from the panel of Comparative Example I, which was thought to be due to the influence of air bubbles, but no unevenness was observed in the panels of Example 1 and Example 2.

From the above, it is clear that the present invention provides a radiation image conversion panel that is highly resistant to temperature changes and physical shocks and does not cause unevenness in image quality, and a method for manufacturing the same. I understand. Furthermore, it can be seen that the method for producing a radiation image storage panel of the present invention allows the strain relaxation layer to be adhered to the phosphor layer and the support with relative ease.

Patent applicant Fuji Photo Film Co., Ltd. Agent Patent attorney Yasuo Yanagawa

Claims (2)

[Claims] 1. In a radiation image storage panel having a support and a phosphor layer formed of agglomerated stimulable phosphor provided on the support, a thermoplastic resin is provided between the phosphor layer and the support. A radiation image conversion panel characterized by being provided with a strain relaxation layer. 2. A laminate is prepared in which a resin layer made of a thermoplastic resin and a phosphor film made of aggregates of stimulable phosphor are arranged in this order on a support, and this laminate is heated under vacuum to melt. A method for manufacturing a radiation image conversion panel, characterized in that it is integrated.