JP2549913C - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention]   The present invention relates to a radiation image conversion method used for a radiation image conversion method using a stimulable phosphor.
It relates to a replacement panel. [Technical Background of the Invention and Prior Art]   As an alternative to the conventional radiographic method, for example, Japanese Patent Application Laid-Open No. 55-12145
A radiation image conversion method using a stimulable phosphor as described in
ing. This method uses a radiation image conversion panel containing a stimulable phosphor (accumulative fluorescent
(Also referred to as a body sheet).
The emitted radiation is absorbed by the stimulable phosphor of the panel, followed by the stimulable phosphor.
Exciting the body with electromagnetic waves (excitation light) such as visible light and infrared light in time series
The radiation energy stored in the stimulable phosphor is converted to fluorescence (stimulated luminescence).
The fluorescence is photoelectrically read to obtain an electric signal, and the obtained electric signal
To reproduce a radiation image of the subject or the subject as a visible image based on the
You.   According to this radiation image conversion method, a combination of a conventional radiographic film and an intensifying screen is used.
Compared to radiographic methods using alignment, information is
There is an advantage that a radiographic image with a large amount of information can be obtained. Therefore, this
The radiation image conversion method is particularly suitable for direct medical radiation imaging such as X-ray imaging for medical diagnosis.
It is very useful in shadows.   The radiation image conversion panel used in the radiation image conversion method has, as a basic structure, a support and
And a stimulable phosphor layer provided on one side thereof. In addition, this phosphor A support is not required if the layer is self-supporting. Also, this excitement
The surface of the phosphor layer opposite to the support (the surface not facing the support) is
Generally, a transparent protective film is provided so that the phosphor layer is chemically altered or physically
Protection from shocks.   The stimulable phosphor layer generally comprises a stimulable phosphor and a bond containing and supporting the stimulable phosphor in a dispersed state.
The stimulable phosphor absorbs radiation such as X-rays and then emits excitation light.
Have the property of exhibiting photostimulated luminescence when irradiated. Therefore, the subject is transparent.
The radiation that has passed or is emitted from the subject is proportional to the radiation dose.
Absorbed by the stimulable phosphor layer of the image conversion panel, the panel
A radiation image is formed as an accumulated image of radiation energy. This accumulated image is
By irradiating the photostimulated light, it can be emitted as photostimulated emission light.
By storing light energy photoelectrically and converting it to electrical signals, radiation energy can be stored.
It becomes possible to image the integrated image.   The radiation image conversion method is a very advantageous image forming method as described above.
The radiation image conversion panel used in the method is the same as the intensifying screen used in the conventional radiography.
Similarly, an image with high sensitivity and good image quality (sharpness, graininess, etc.) is given.
It is hoped that it is.   The sensitivity of the radiation image conversion panel is basically determined by the stimulable fluorescent light contained in the panel.
It depends on the total photostimulated luminescence of the body, and this total
However, it also depends on the phosphor content in the phosphor layer. High phosphor content
This means that the absorption of radiation such as X-rays is also large.
High sensitivity is obtained, and at the same time, image quality (particularly, granularity) is improved. On the other hand, the phosphor layer
Phosphor content is constant, the phosphor particles are densely packed
The more the layer thickness becomes thinner, the smaller the spread of the excitation light due to scattering becomes.
And a relatively high sharpness can be obtained.   The present applicant has developed a radiation image conversion panel having a phosphor layer densely filled with phosphor.
One is to reduce the porosity of the phosphor layer by compressing the phosphor layer.
Has already filed an application for a radiation image conversion panel and a method for manufacturing the same.
26299, JP-A-59-126300).   The above-mentioned radiation image conversion panel compresses the phosphor layer to thereby form the phosphor layer.
The density of the light body was higher than that of the conventional radiation image conversion panel. The result
As a result, this radiation image conversion panel had excellent sharpness, but on the other hand,
Since the phosphor is partially destroyed by the compression process, it is rather deteriorated in terms of granularity.
There was a problem that there was a case. [Summary of the Invention]   The present invention provides a radiation image conversion having excellent sharpness and excellent granularity.
It is intended to provide a panel.   The object of the present invention is to provide a support of the present invention and a binder provided on the support.
Compressed by heating at a temperature above the softening temperature or melting point of the binder
A radiation image conversion panel substantially constituted by the formed phosphor layer.
The filling rate of the phosphor in the phosphor layer is 70% or more;
Softening temperature of 30 ° C to 150 ° C for 10% to 100% by weight of the binder
Or radiation image conversion characterized by being a thermoplastic elastomer having a melting point
Can be achieved with panels.   In the radiation image storage panel of the present invention, the filling rate of the phosphor is reduced to 70% or less by the compression process.
As above, since the binder of the phosphor layer is made of thermoplastic elastomer,
During shrinking, the elastomer is heated at a temperature higher than the softening temperature or melting point of the
The degree of damage to the light body can be reduced. In addition, it consists of a phosphor and a binder in advance.
Prepare a phosphor sheet, place this phosphor sheet on a support, and
If the compression is carried out simultaneously with the setting on the support at the softening temperature or the melting point or higher,
The breakage of the phosphor can be prevented.   That is, during compression, the binder is separated into a binder at a temperature higher than the softening temperature or the melting point.
The scattered phosphor crystals receive pressure with some degree of freedom,
The phosphor crystals can be oriented by the applied pressure. Furthermore, a phosphor sheet
When pressure is applied without fixing to the support, and it is installed on the support while compressing
At the same time, the pressure applied to the phosphor sheet works simultaneously to orient the phosphor crystals.
In addition, even if the phosphor sheet is fixed, even if the pressure
Work to spread and spread thinly. In this case, the phosphor sheet is fixed on the support. Higher phosphor loading even when compressed at the same pressure, compared to when pressed in a fixed state
Rate can be obtained.   Preferred embodiments of the present invention are listed below. (1) The above elastomer is polystyrene, polyolefin, polyurethane, polyurethane
Ester, polyamide, polybutadiene, polyethylene vinyl acetate, polychlorinated
Vinyl, natural rubber, fluoro rubber, polyisoprene, chlorinated polyethylene, polystyrene
At least one selected from the group consisting of butadiene rubber and silicone rubber
A radiation image conversion panel characterized in that it is a thermoplastic elastomer. (2) The binder is a 100% by weight thermoplastic elastomer.
Radiation image conversion panel. [Configuration of the Invention]   The radiation image conversion panel of the present invention is manufactured, for example, by the method described below.
be able to.   To manufacture the radiation image conversion panel of the present invention, a) forming a phosphor sheet comprising a binder and a stimulable phosphor, b) The phosphor sheet is placed on a support, and the softening temperature or the melting point of the binder is lower than the softening temperature or the melting point.
Bonding the phosphor sheet on a support while compressing at the above temperature, It is preferable to manufacture by the two processes.   First, step a) will be described.   The phosphor sheet, which is the phosphor layer of the radiation image conversion panel, is stimulable in the binder solution.
The coating solution in which the phosphor is uniformly dispersed is applied on a temporary support for forming a phosphor sheet,
It can be manufactured by drying and peeling off from the temporary support.   Hereinafter, the phosphor used in the present invention will be described.   As described above, the stimulable phosphor is irradiated with radiation and then irradiated with excitation light.
Although it is a phosphor that exhibits stimulated emission, the wavelength is 400 to 900 nm from a practical viewpoint.
Fluorescence exhibiting stimulated emission in the wavelength range of 300 to 500 nm by excitation light in the range
Desirably the body. Stimulable fluorescence used in the radiation image conversion panel of the present invention
Examples of bodies are   BaSO described in JP-A-48-80487_Four: AX and JP SrSO described in JP-A-48-80489_Four: Fluorescence represented by AX
body,   Li described in JP-A-53-39277_TwoB_FourO₇: Cu, Ag,   Li described in JP-A-54-47883_TwoO (B_TwoO_Two)_x: Cu
And Li_TwoO ・ (B_TwoO_Two)_x: Cu, Ag,   SrS: Ce, Sm described in U.S. Pat. No. 3,859,527.
, SrS: Eu, Sm, ThO_Two: Er and La_TwoO_TwoS: Eu, Sm,   ZnS: Cu, Pb, BaO described in JP-A-55-12142
・ XAl_TwoO_Three: Eu (provided that 0.8 ≦ x ≦ 10) and M^IIOxSiO_Two
: A (however, M^IIIs Mg, Ca, 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),   It is described in JP-A-55-12143 (Ba)_1-xy, Mg_x, Ca_y
) FX: aEu²⁺(Where X is at least one of Cl and Br
, X and y are 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 (provided that L
n is at least one of La, Y, Gd and Lu, X is Cl and Br
A is at least one of Ce and Tb, and
, X is 0 <x <0.1),   JP-A-55-12145 (Ba)_1-x, M²⁺ _x) FX: y
A (however, M²⁺Represents at least one of Mg, Ca, Sr, Zn, and Cd.
X is at least one of Cl, Br, and I, A is Eu, Tb, Ce
, Tm, Dy, Pr, Ho, Nd, Yb, and Er,
And x is 0 ≦ x ≦ 0.6, and y is 0 ≦ y ≦ 0.2),   BaFX: xCe, yA described in JP-A-55-843897.
Represented phosphor,   M described in JP-A-55-160078^IIFX xA: yLn [However,
M^IIIs at least one of Ba, Ca, Sr, Mg, Zn, and Cd; Is BeO, MgO, CaO, SrO, BaO, ZnO, Al_TwoO_Three, Y_TwoO_Three, La
_TwoO_Three, In_TwoO_Three, SiO_Two, TlO_Two, ZrO_Two, GeO_Two, SnO_Two, Nb_TwoO_Five,
Ta_TwoO_FiveAnd ThO_TwoLn is Eu, Tb, Ce, Tm
, Dy, Pr, Ho, Nd, Yb, Er, Sm, and Gd
X is at least one of Cl, Br and I, and x and y are
5 × 10 each^-Five≤ x ≤ 0.5, and 0 <y ≤ 0.2].
Phosphor,   (Ba) described in JP-A-56-116777._1-x, M^II _x) F_Two・ ABaX_Two
: YEu, zA [where M^IIIs beryllium, magnesium, calcium, strike
At least one of rontium, zinc, and cadmium, X is chlorine or bromine
A is at least one of zirconium and scandium.
A, x, y, and z are each 0.5 ≦ a ≦ 1
. 25, 0 ≦ x ≦ 1, 10^-6≦ y ≦ 2 × 10^-1, And 0 <z ≦ 10^-2Is]
A phosphor represented by the composition formula:   (Ba) described in JP-A-57-23673._1-x, M^II _x) F_Two・ ABaX_Two: Y
Eu, zB [where M^IIIs beryllium, magnesium, calcium, stron
At least one of titanium, zinc and cadmium, X is chlorine, bromine and
A, x, y and z are each at least 0.5 ≦ a
≦ 1.25, 0 ≦ x ≦ 1, 10^-6≦ y ≦ 2 × 10^-1And 0 <z ≦ 2 × 10^-1In
The phosphor represented by the composition formula:   (Ba) described in JP-A-57-23675._1-x, M^II _x) F_Two・ ABaX_Two: Y
Eu, zA [where M^IIIs beryllium, magnesium, calcium, stron
At least one of titanium, zinc and cadmium, X is chlorine, bromine and
A is at least one of iodine and A is at least one of arsenic and silicon
A, x, y and z are respectively 0.5 ≦ a ≦ 1.25, 0 ≦ x ≦ 1, 10
^-6≦ y ≦ 2 × 10^-1, And 0 <z ≦ 5 × 10^-1Is represented by the composition formula
Phosphor,   M described in JP-A-58-69281^IIIOX: xCe [however
M^IIIAre Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb
, And at least one trivalent metal selected from the group consisting of
And Br or both, and x is 0 <x <0.1.
A phosphor represented by the composition formula:   Ba described in JP-A-58-206678._1-xM_{x / 2}L_{x / 2}FX:
yEu²⁺[Where M is selected from the group consisting of Li, Na, K, Rb and Cs
L represents Sc, Y, La, Ce, Pr
, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al
, Ga, In, and at least one trivalent metal selected from the group consisting of Tl
X is at least one member selected from the group consisting of Cl, Br and I
Represents xenogen; and x is 10^-2≦ x ≦ 0.5, y is 0 <y ≦ 0.1
A phosphor represented by the composition formula:   BaFX.xA: yEu described in JP-A-59-27980²⁺[
Here, X is at least one kind selected from the group consisting of Cl, Br and I.
A is a calcined product of a tetrafluoroborate compound; and
x is 10^-6≤ x ≤ 0.1, and y is 0 <y ≤ 0.1].
Phosphor,   XM described in JP-A-59-38278_Three(PO_Four)_Two・ NX_Two: Y
A, M_Three(PO_Four)_Two: YA and nReX_Three・ MAX '_Two: XEu, nReX_Two・ M
AX '_Two: XEu, ySm, M^I・ AM^IIX '_Two・ BM^IIIX "_Three: Represented by cA
Phosphor,   BaFX.xA: yEu described in JP-A-59-47289.²⁺[
Here, X is at least one kind selected from the group consisting of Cl, Br and I.
A is halogen; A is hexafluorosilicic acid, hexafluorotitanic acid, and
Consisting of monovalent or divalent metal salts of hexafluorozirconate and hexafluorozirconate
A calcined product of at least one compound selected from the group of fluoro compounds; and
x is 10^-6≤ x ≤ 0.1, and y is 0 <y ≤ 0.1].
Phosphor,   BaFX.xNaX ': aEu described in JP-A-59-56479.
²⁺[Where X and X 'are at least one of Cl, Br and I, respectively] And x and a are respectively 0 <x ≦ 2 and 0 <a ≦ 0.2
A phosphor represented by the composition formula:   M described in JP-A-59-565480.^IIFX xNaX ': yE
u²⁺: ZA [where M^IIIs a small number selected from the group consisting of Ba, Sr and Ca
At least one kind of alkaline earth metal; X and X 'are each Cl, Br
Is at least one halogen selected from the group consisting of
At least one transition metal selected from 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
A phosphor represented by the composition formula:   M described in JP-A-59-75200^IIFX ・ aM^IX'bM
’^IIX "_Two・ CM^IIIX "'_ThreeXA: yEu²⁺[However, M^IIAre Ba, Sr, and
At least one alkaline earth metal selected from the group consisting of^I
Is at least one member selected from the group consisting of Li, Na, K, Rb, and Cs
An alkali metal; M '^IIIs at least selected from the group consisting of Be and Mg
Is also a kind of divalent metal; M^IIIIs a group consisting of Al, Ga, In, and Tl
A is a metal oxide; X is Cl
X 'is at least one halogen selected from the group consisting of:
, X ″ and X ″ ′ are at least one member selected from the group consisting of F, Cl, Br, and I.
Are a kind of halogen; and a is 0 ≦ a ≦ 2, b is 0 ≦ b ≦ 10^-2, C
Is 0 ≦ c ≦ 10^-2And a + bfc ≧ 10^-6X is 0 <x ≦ 0.5, y is
0 <y ≦ 0.2], a phosphor represented by a composition formula:   M described in JP-A-60-84381^IIX_Two・ AM^IIX '_Two: XE
u²⁺[However, M^IIIs at least selected from the group consisting of Ba, Sr and Ca
A kind of alkaline earth metal; X and X 'are a group consisting of Cl, Br and I
At least one halogen selected from X and X'X '; and a is 0
. 1 ≦ a ≦ 10.0, and x is 0 <x ≦ 0.2].
Phosphor,   M described in JP-A-60-101173^IIFX ・ aM^IX ': x
Eu²⁺[However, M^IIIs at least selected from the group consisting of Ba, Sr and Ca Is also a kind of alkaline earth metal;^IIs selected from the group consisting of Rb and Cs
X is a group consisting of Cl, Br and I
X 'is F, Cl, Br and I
At least one halogen selected from the group consisting of:
Are respectively 0 ≦ a ≦ 4.0 and 0 <x ≦ 0.2].
Stimulable phosphor,   M described in JP-A-62-25189^IX: xBi [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 Cl, Br and I
And x is a numerical value in the range of 0 <x ≦ 0.2].
Stimulable phosphor, And the like.   In addition, M described in Japanese Patent Application Laid-Open No. 60-84381^IIX_Two・ AM^II
X '_Two: XEu²⁺In the stimulable phosphor, the following additives are added.^IIX_Two・ AM^II
X '_TwoIt may be contained in the following ratio per mole.   BM described in JP-A-60-166379^IX "(however, M^IIs
At least one alkali metal selected from the group consisting of Rb and Cs,
X ″ is at least one halogen selected from the group consisting of F, Cl, Br and I
And b is 0 <b ≦ 10.0);
BKX ".cMgX" 'described in the gazette_Two・ DM^IIIX ""_Three(However, M^IIIIs
At least one trivalent gold selected from the group consisting of Sc, Y, La, Gd and Lu
X ", X" 'and X "" are each a group consisting of F, Cl, Br and I
At least one halogen selected from the group consisting of
0 ≦ b ≦ 2.0, 0 ≦ c ≦ 2.0, 0 ≦ d ≦ 2.0, and 2 × 10
^-Five≦ b + c + d); y described in JP-A-60-228592
B (where y is 2 × 10^-Four≦ y ≦ 2 × 10^-1JP-A-60-2285
BA described in Japanese Patent Publication No. 93 (where A is SiO_TwoAnd P_TwoO_FiveConsists of
At least one oxide selected from the group;^-Four≦ b ≦ 2 × 1
0^-1BSi described in JP-A-61-120883. O (where b is 0 <b ≦ 3 × 10^-2JP-A-61-120885
BSnX "2 (where X" is from F, Cl, Br and I)
At least one halogen selected from the group consisting of:
^-3BCsX ".c described in JP-A-61-235486.
SnX "'_Two(However, X ″ and X ″ ′ are each composed of F, Cl, Br and I, respectively)
At least one halogen selected from the group consisting of
0 <b ≦ 10.0 and 10 respectively^-6≦ c ≦ 2 × 10^-2); And
BCsX ".yLn described in JP-A-61-235487³⁺(However, X
"Represents 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, Dy, Ho,
At least one rare earth element selected from the group consisting of Er, Tm, Yb and Lu
And b and y are 0 <b ≦ 10.0 and 10 respectively.^-6≦ y ≦
1.8 × 10^-1Is).   Among the stimulable phosphors described above, divalent europium-activated alkaline earth metal halides
Phosphors and cerium-activated rare earth oxyhalide phosphors
It is particularly preferable because it shows stimulated emission. However, the stimulable phosphor used in the present invention is
It is not limited to the above-mentioned phosphors.
Any phosphor may be used as long as it emits stimulable light when it is used.   Add the stimulable phosphor and binder as described above to a suitable solvent and mix them thoroughly.
Thus, a coating solution in which the stimulable phosphor is uniformly dispersed in the binder solution is prepared.   The binder has a softening temperature or melting point of 30 ° C. to 150 ° C. in an amount of 10% by weight or more.
Use a thermoplastic elastomer. Thermoplastic elastomers have elasticity at room temperature,
As it becomes fluid when heated, the phosphor will not be damaged by the pressure during compression.
Can be prevented. Examples of thermoplastic elastomers include polystyrene and polystyrene.
Polyolefin, polyurethane, polyester, polyamide, polybutadiene, poly
Polyethylene vinyl acetate, polyvinyl chloride, natural rubber, fluoro rubber, polyisoprene
Chlorinated polyethylene, styrene-butadiene rubber, silicone rubber, etc.
Can be   The component ratio of the thermoplastic elastomer in the binder is 10% by weight or less as described above. When the content is not more than 100% by weight, the effect of the present invention can be obtained, but the binder is required.
As much thermoplastic elastomer as possible, especially 100% by weight of thermoplastic elastomer
Preferably.   Examples of the solvent for preparing the coating solution include methanol, ethanol, and n-propanol.
And lower alcohols such as n-butanol; methylene chloride, ethylene chloride
Chloride and other hydrocarbons; acetone, methyl ethyl ketone, methyl ether
Ketones such as sodium butyl ketone; lower grades such as methyl acetate, ethyl acetate and butyl acetate
Esters of fatty acids and lower alcohols; dioxane, ethylene glycol monoe
Ethers such as tyl ether and ethylene glycol monomethyl ether; and
And mixtures thereof.   The composition ratio between the binder and the stimulable phosphor in the coating solution is determined by the target radiation image conversion.
Although it depends on the characteristics of the panel and the type of the phosphor, it is generally 1: 1 to 1: 1.
00 (weight ratio) and in particular from 1: 8 to 1:40 (weight ratio)
It is preferable to select from the range.   In addition, the coating liquid is used to improve the dispersibility of the phosphor in the coating liquid.
The dispersant and the bonding strength between the binder and the phosphor in the phosphor layer after formation are improved.
Various additives such as a plasticizer may be mixed. like that
Examples of dispersants used for the purpose include phthalic acid, stearic acid, caproic acid,
Lipophilic surfactants and the like can be mentioned. And as an example of a plasticizer, phosphoric acid
Phosphate esters such as triphenyl, tricresyl phosphate and diphenyl phosphate; phthalates
Phthalates such as diethyl phthalate and dimethoxyethyl phthalate; glycolic acid
Glycolic acids such as ethylphthalylethyl and butylphthalylbutyl glycolate
Esters; polyesters of triethylene glycol and adipic acid, di
Polyethylene glycol such as polyester of ethylene glycol and succinic acid
And a polyester of an aliphatic dibasic acid.   Next, the coating solution containing the phosphor and the binder prepared as described above was used.
A uniform coating is applied to the surface of the temporary support to form a coating solution.
You. This coating operation is performed by a usual coating means, for example, a doctor blade, a roll coater.
And a knife coater.   The temporary support may be, for example, a glass, metal plate, or a conventional radiographic method.
Materials used as supports for intensifying screens (or intensifying screens)
Or any material known as a support for the radiation image storage panel.
it can. Examples of such materials include cellulose acetate, polyester,
Polyethylene terephthalate, polyamide, polyimide, triacetate, poly
Films of plastic materials such as carbonate, aluminum foil, aluminum
Metal sheets such as aluminum alloy foil, ordinary paper, baryta paper, resin-coated paper,
Pigment paper containing pigments such as tan, polyvinyl alcohol, etc.
Ceramics such as ground paper, alumina, zirconia, magnesia, titania, etc.
A plate or a sheet can be used.   Apply the coating solution for forming the phosphor layer on the temporary support, and after drying, apply
Then, a phosphor sheet to be a phosphor layer of the radiation image conversion panel is obtained. Therefore, the temporary support
The surface of the support is coated with a release agent in advance, and the formed phosphor sheet is used as a temporary support.
It is preferable to make it easy to peel off.   Next, step b) will be described.   First, separately from the phosphor sheet formed as described above, the support of the radiation image conversion panel is provided.
Prepare a holding body. This support is a temporary support used when forming the phosphor sheet.
It can be arbitrarily selected from similar materials.   In known radiation image conversion panels, in order to strengthen the bond between the support and the phosphor layer
Or sensitivity or image quality as a radiation image conversion panel (sharpness, granularity)
Surface of the support on which the phosphor layer is provided, such as gelatin,
Applying a molecular substance to form an adhesion-imparting layer, or reflecting light such as titanium dioxide
Light-reflective layer made of absorbing material or light-absorbing material such as carbon black.
It is known to provide a light absorbing layer. The support used in the present invention
However, these various layers can be provided, and their configuration is
It can be arbitrarily selected according to the purpose and use of the conversion panel.   Further, as described in JP-A-58-200200, the obtained
In order to improve the sharpness of the image, the surface of the support on the phosphor layer side (the phosphor of the support)
An adhesiveness-imparting layer, a light-reflecting layer, or a light-absorbing layer is provided on the layer side surface In that case, the surface may mean fine irregularities.   The phosphor sheet obtained in step a) is placed on a support, and the softening temperature of the binder
Alternatively, it is adhered to the support while compressing at a temperature equal to or higher than the melting point.   As described above, the phosphor sheet is compressed without being fixed on the support in advance.
Can be spread out thinly, not only to prevent phosphor damage, but also to secure the sheet
Higher phosphor filling rate can be obtained with the same pressure as compared with the case where
.   An example of a compression device used for the compression processing of the present invention is a calendar row.
And generally known ones such as a hot press and a hot press. For example
The compression treatment by a calender roll is performed by pressing the phosphor screen obtained in step a) on a support.
Place a roller between the rollers heated above the softening or melting point of the binder.
This is done by passing at a speed. However, the compression device used in the present invention
Is not limited to these, and the pressure is applied while heating the sheet as described above.
Anything can be used as long as it can be reduced.   The pressure during compression is 50 kgw / cm^TwoThis is generally the case.   The porosity of the phosphor layer formed on the support as described above is expressed by the following equation (I).
It can be determined more theoretically.   (Where V is the total volume of the phosphor layer)             Vair: air volume in the phosphor layer             A: Total weight of phosphor             ρ_x   ： Phosphor density             ρ_y   : Binder density             ρair: Air density              a: Weight of phosphor              b: weight of binder)   Furthermore, in equation (I), ρair is almost 0, so equation (I) is approximately
(II).   (However, V, Vair, A, ρ_x, Ρ_y, A, and b have the same definitions as in formula (I)
Is)   In the present invention, the porosity of the phosphor layer was calculated by the formula (II).   The filling rate of the phosphor can be determined by the following equation (III).   (However, V, Vair, A, ρ_x, Ρ_y, A, and b have the same definitions as in formula (I)
Is)   In a normal radiation image conversion panel, as described above, it is opposite to the side in contact with the support.
Transparent on the opposite phosphor layer surface to protect the phosphor layer physically and chemically
Protective film is provided. Such a transparent protective film is used for the radiation image conversion pattern of the present invention.
It is preferable to install the tunnel.   The transparent protective film is made of cellulose acetate, nitrocellulose, etc.
Derivatives; or polymethyl methacrylate, polyvinyl butyral, polyvinyl
Nil formal, polycarbonate, polyvinyl acetate, vinyl chloride / vinyl acetate
Dissolve a transparent polymer such as a synthetic polymer such as a copolymer in a suitable solvent
Can be formed by applying the prepared solution to the surface of the phosphor layer.
. Or polyethylene terephthalate, polyethylene, polyvinylidene chloride,
Plastic sheet made of polyamide etc .; protection of transparent glass plate etc.
A film forming sheet is separately formed and adhered to the surface of the phosphor layer using a suitable adhesive.
It can also be formed by such a method.   The thickness of the transparent protective film is generally in the range of 0.1 to 20 μm.   Further, in order to improve the sharpness of the obtained image, at least one of the above
A coloring agent that absorbs excitation light and does not absorb photostimulated light may be added to such a layer.
(See Japanese Patent Publication No. 59-23400).   Next, examples of the present invention will be described. However, each of these embodiments limits the present invention.
Not something. [Example 1]   As a coating solution for forming a phosphor sheet,     Phosphor: BaFBr_0.9I_0.1: Eu²⁺                  ...... 200 g     Binder: polyurethane         (Sumitomo Bayer Urethane Co., Ltd.           Desmolak TPKL-5-2625           [Solid content 40%], softening temperature 45 ° C 22.5g     Yellowing inhibitor: Epoxy resin           (Yuka Kasei Epoxy Co., Ltd. Epicoat 1001) 1.0 g To a 1: 1 mixed solvent of methyl ethyl ketone and 2-propanol.
The mixture was dispersed with a mixer to prepare a coating solution having a viscosity of 30 PS (25 ° C.)
(Agent / phosphor ratio = 1/20). This is applied to the polyether coated with the silicone release agent.
After coating on Tylene terephthalate (temporary support, thickness 180 μm) and drying,
The phosphor sheet was peeled off from the temporary support.   On the other hand, as a light reflection layer forming coating liquid, BaFBr (containing 90% of particles having a particle diameter of 1 to 5 μm) 214 g Soft acrylic resin solid content 25.7g Epoxy resin 10.7g Nitrocellulose (nitrification degree 11.5%, solid content 10% by weight) ... 64 g Is added to methyl ethyl ketone and dispersed with a propeller mixer to give a viscosity of 25-3.
A dispersion of 5 PS (25 ° C.) was prepared.   Also, as a separate undercoat layer forming coating solution, Soft acrylic resin solid content 90g Nitrocellulose 50 g Is added to methyl ethyl ketone, dispersed and mixed, and a mixture having a viscosity of 3 to 6 PS (25 ° C.) is added.
A liquid dispersion was prepared.   Horizontally place 300 μm thick polyethylene terephthalate (support) on a glass plate And apply the undercoat layer-forming coating solution on the support using a doctor blade.
After coating, gradually increase the temperature from 25 ° C to 100 ° C to dry the coated film.
An undercoat layer was formed on the support (thickness of coating film: 15 μm). In addition, the above light reflection
A coating liquid for forming a layer is applied (thickness of the applied film: 60 μm), and dried in the same manner.
An undercoat layer and a light reflecting layer were formed on the support. The phosphor screen created first on this
The plate was placed and compression was performed.   Compression is performed using a calender roll at 400 kgw / cm.^TwoPressure, 80 ° C temperature
Performed continuously in degrees. Due to this compression, the phosphor sheet and the light reflecting layer on the support become
Completely fused.   After this compression, a polyethylene adhesive coated on one side with a polyester adhesive
Adhesion of transparent film of phthalate (thickness 10μm) with adhesive layer side down
Thus, a transparent protective film was formed.   As described above, the support, the undercoat layer, the light reflection layer, the phosphor layer, and the transparent protective film are formed.
The resulting radiation image conversion panel was manufactured. [Example 2]   In Example 1, the pressure during compression was set to 600 kgw / cm.^TwoImplemented except for
Consists of a support, an undercoat layer, a light reflecting layer, a phosphor layer, and a transparent protective film in the same manner as in Example 1.
The manufactured radiation image conversion panel was manufactured. [Comparative Example 1]   After forming an undercoat layer in the same manner as in Example 1, a coating liquid for forming a reflective layer was applied.
The coating liquid for forming the phosphor layer was continuously applied thereon before the coating liquid of
. The temperature is gradually raised from 25 ° C. to 100 ° C., and drying is performed.
And a sheet comprising a light reflecting layer and a phosphor layer. Next, this sheet was used in Example 1.
400 Kgw / cm using a calender roll as in^TwoPressure, 80 ° C temperature
Compressed. Further, a protective layer was provided in the same manner as in Example 1, and the support,
A radiation image conversion panel composed of an undercoat layer, a light reflection layer, a phosphor layer, and a transparent protective film
Manufactured. [Comparative Example 2]   In Comparative Example 1, the pressure during compression was set to 600 kgw / cm.^TwoComparison except for Consists of a support, an undercoat layer, a light reflecting layer, a phosphor layer, and a transparent protective film in the same manner as in Example 1.
The manufactured radiation image conversion panel was manufactured. [Comparative Example 3]   In Comparative Example 1, except that no compression was performed,
Radiation image conversion composed of support, undercoat layer, light reflection layer, phosphor layer, and transparent protective film
Panels were manufactured.         [Phosphor filling rate and porosity of phosphor layer of radiation image conversion panel]   Phosphors of each radiation image conversion panel of Examples and Comparative Examples manufactured as described above
The filling rate and porosity of the phosphor in the layer are determined by the equations (II) and (III).
I asked. However, the density of the phosphor is 5.1 g / cm.^Three, Binder density 1.14
g / cm^ThreeIt is.   The results are shown in Table 1.  As is clear from Table 1, the radiation image conversion panel of the present invention was compressed at the same pressure.
Compared with the radiation image conversion panel, the filling rate of the phosphor is higher and the porosity is lower.
It turns out that it is.                    [Evaluation of image quality of radiation image conversion panel]   The image quality of each radiation image conversion panel manufactured as described above is described below.
It was evaluated by the method described. That is, a tube voltage of 80 KV is applied to the radiation image conversion panel.
After irradiation with X-rays of p, scanning with He-Ne laser light (632.8 nm) was performed.
Excites the phosphor, receives the stimulated emission emitted from the phosphor layer and converts it into an electrical signal.
This was reproduced as an image by an image reproducing device to obtain an image on a display device. Profit
By the modulation transfer function (MTF) of the obtained image (spatial frequency: 2 cycles / mm)
The sharpness and the granularity (RMS) at a dose of 0.1 mR were measured.   The results obtained are summarized in the form of a graph in FIG.   FIG. 1 shows the sharpness (MTF value at a spatial frequency of 2 cycles / mm) on the vertical axis.
, Indicating that the sharper the plot is, the higher the sharpness is. The horizontal axis is
, Indicates that the graininess is better, as plotted to the left.   As is clear from FIG. 1, the radiation image conversion panel of the present invention is compressed at the same pressure.
Slightly improved sharpness and reduced granularity compared to the comparative panel
As for this, it can be seen that it has greatly improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing the image quality of a radiation image conversion panel according to an example and a comparative example.

Claims (1)

Claims: 1. A support comprising a support, a binder provided on the support, and a stimulable phosphor. A radiation image conversion panel substantially constituted by a formed phosphor layer, wherein the filling rate of the phosphor in the phosphor layer is 70% or more, and one of the binders is used.
A radiation image conversion panel, wherein 0% to 100% by weight is a thermoplastic elastomer having a softening temperature or melting point of 30 ° C to 150 ° C.