JPS58196287A - Preparation of radiation image conversion screen - Google Patents

Abstract

PURPOSE:To obtain a radiation image conversion screen such as sensitized paper, fluorescent board, etc., having high sensitivity and improved image properties, obtained by laminating a fluorescent substance layer of a green coloring rare earth element on a blue coloring fluorescent substance layer to give a fluorescent substance layer, laminating further a protecting film of transparent resin on it. CONSTITUTION:(A) Fluorescent substance particles of green coloring rare earth element for radiation and (B) fluorescent substance particles of blue coloring for radiation having smaller average particle diameters or specific gravity than the component A are dispersed into a binder resin solution, to give a fluorescent substance coating solution. The solution is applied to a protecting film of a transparent resin preformed on a flat base, dried in a stationary state, and a separated fluorescent substance layer consisting of the component B mainly in the upper part and the component A in the lower part is prepared. The fluorescent substance layer integrated with the protecting film is released from the base, and bonded to a substrate in such a way that the fluorescent substance layer side becomes a contact face, to give the desired radiation image conversion screen.

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a radiation scar conversion screen.

j! In detail, a radiation intensifying screen (hereinafter simply referred to as "sensitizing screen") has a plurality of phosphor layers consisting of a green-emitting rare earth phosphor layer and a blue-emitting phosphor layer, and exhibits high sensitivity and excellent AII characteristics. A radiation phosphor plate (hereinafter simply abbreviated as a ``fluorescent plate''), that is, a radiation image conversion screen (hereinafter, an intensifying screen and a phosphor plate are collectively referred to as 1).
- a method of manufacturing a radiation image conversion screen).

As is well known, radiation image conversion screens are used for purposes such as medical diagnosis and non-destructive testing of industrial products.
It absorbs the radiation that has passed through the object and emits ultraviolet rays or visual sources (7), converting the radiation image into ultraviolet damage or visual sources.

The radiation image conversion screen is an intensifying screen and 1. When performing radiography, it is placed in close contact with a radiographic film (hereinafter simply referred to as ``film'') and used for photography (7. Conversion into ultraviolet scratches or visible light 1-1 This was recorded by exposing it to film, and on the other hand, when used as a fluorescent plate, it was converted into a 51 visual image with this magnifying glass bar and surface. The radiation image of the subject is photographed with a photographic camera, projected on a television in combination with an imaging tube, or directly observed with the naked eye.The structure of the radiation image conversion screen is basically paper. ,
It consists of a support such as 1-lastiquette and a phosphor layer formed on the support. The phosphor layer is composed of a binder and a phosphor (radiation phosphor J) that is dispersed in the binder and emits light efficiently by radiation action such as X-rays. Its surface is protected by a membrane.

In medical diagnosis using radiography, a more sensitive radiography system (a combination of film and intensifying screen 1) is required in order to reduce the radiation dose to the patient, who is the subject. Image quality (sharpness, graininess,
Since there is a demand for a radiographic system capable of obtaining contrast 2 contrast, it is rumored that an intensifying screen has high sensitivity and good sharpness, graininess, and contrast. Similarly, fluorescent plates can also be used to reduce the II dose to the patient and to improve the II dose.
i111! In order to obtain L images, a phosphor plate with higher sensitivity and better contrast is desired.As a more sensitive radiation image conversion screen, a phosphor plate with fil, a green light-emitting phosphor, and a phosphor plate with a green light emitting phosphor is required. The most active xisulfide phosphor (t Ln, Tb 1p02
s (where Ln is at least one of La, Gd, and Lu) (U.S. Patent No. &725,704)
No. 1 and terbium-activated yttrium oxysulfide 1 phosphor ((Y, Tb 1yo
t S ) (US [%1 clock λ738
, No. 856 No. 1, etc., has been developed, and among them, rare earth phosphors that emit green light, especially terbium-activated gadolinium oxysulfide fluorescers, have been developed. Body (t Ge
l, Tb Jto, s l - Purpium-enhanced unku/bow; No. 17 Luaide S + body mouth La, Tb1202
Intensifying screens using rare earth oxosulfide phosphors such as 8) have several times the sensitivity of intensifying screens using the conventionally widely used calcium tungstate phosphor tCaWO,l. However, since it has relatively good graininess compared to other high-sensitivity intensifying screens, it has a spectral sensitivity from the blue region to the green region.
It is used in a high-sensitivity radiographic system in combination with a film of ``orthotype'' (hereinafter abbreviated as ``orthotype''). By the way, in recent high-sensitivity radiographic systems that combine a green-emitting rare earth intensifying screen and an ornotide film, fine particles are used to reduce the amount of silver used in the film and to improve image quality, especially graininess, in the high-sensitivity region. of·
The use of low-sensitivity Taigu orthofilm has become mainstream for silver oxide. Therefore, the subject's exposure to radiation is 4!
5! In order to reduce the amount of shading, efforts are being made to further increase the sensitivity of intensifying screens, and there is also a strong need to improve the sharpness of intensifying screens, which decreases due to increased sensitivity.

In addition, among green-emitting rare earth phosphors, Gadoli, -Uno, and Ox7 sulfide phosphors, which are particularly prized for use in high-sensitivity intensifying screens, have an absorption edge at 50.2 KeV, so they are used. Due to the Xwi absorption characteristics of the phosphor, the intensifying screen has a tube voltage range of 60
Contrast is poor at ~140KV,, +
The g-FtL change of the intensifying screen due to the tube voltage change becomes large, making it difficult to set the conditions for photographing.1. Tears at the disadvantage of being ugly17
ing.

The present invention was made in view of the above-mentioned situation in a radiological diagnostic system using a radiation image conversion screen, and combines an orthotie 7'' film with an intensifying screen and 1. When used with a green light-emitting rare earth phosphor, it has a sensitivity equal to or higher than that of a conventional intensifying screen using a green-emitting rare earth phosphor.
To provide a round manufacturing method for obtaining a radiation flaw conversion screen that maintains granularity in bamboo to obtain images with good sharpness and contrast, and has less sensitivity dependence on X# tube voltage than that of 91mm. The purpose is to

Furthermore, when the present invention is used as a fluorescent plate in combination with a 4-ray camera or an F'i It is a further object of this invention to provide a ninth manufacturing method which provides a radiation HyJ conversion screen with particularly improved contrast.

The inventors of the present invention did not achieve the above object, but used the phosphor 1- of the radiation image conversion screen.
As a result of repeated studies on these combinations and how to arrange them, we found that the combination of cloth and fireflies that emit green light when irradiated with HX radiant heat, and the average particle diameter or ratio M
J, is small and emits blue light when irradiated with radiation',
r'z ft.

(7) When drying j-fL to prepare a phosphor layer, apply a phosphor coating solution consisting of fluorophore, i.t. Particle L7) Utilizing the difference in particle size or specific gravity 1. Separate the green-emitting phosphor particles and the blue-emitting phosphor particles into layers in the phosphor layer. (7) By preparing a plurality of phosphor layers, in which the phosphor layer is made of a green-emitting rare earth phosphor, and the support side is a phosphor I- mainly made of a blue-emitting π-fluorescent material, Achieving the Objectives 1 - We have discovered that it is possible to achieve the objectives 17 and have completed the present invention.

The method for producing a radiation image converting screen of the present invention includes green radiation-use rare earth phosphor particles and radiation-use blue-emission phosphor particles having a smaller average particle diameter or specific gravity in a binder resin. The dispersed phosphor coating liquid is applied onto a transparent resin retentive film that has been previously formed on a smooth substrate (2. The green luminescent rare earth for radiation use is dried by allowing it to stand still). The phosphor particles and the blue-emitting phosphor particles for radiation described in 411 are separated (forming a phosphor layer of 7) 12, I7
After that, the phosphor layer integrated with the transparent resin fMm layer is peeled off from the 4111 substrate, and -C1 the phosphor layer side (opposite to the transparent resin retention film) is the adhesive surface. By adhering to the support so that
The present invention is characterized in that a radiation image conversion screen is obtained in which a phosphor layer mainly composed of the green-emitting rare earth phosphor for radiation and the transparent resin protective film are laminated in this order.

The radiation image converting screen obtained by the manufacturing method of the present invention has a phosphor layer mainly consisting of a blue-emitting phosphor between the phosphor layer mainly consisting of a green-emitting rare earth phosphor and the support. It emits blue and green light17 and has a sensitivity equal to or greater than that of a conventional radiation image converting screen made only of green-emitting rare earth phosphors. Sara K
Compared to conventional radiation afl conversion screens, images with better image quality, especially contrast, can be obtained, and this can be achieved by using an intensifying screen and 1. When used in combination with OrthoTie 1 film, the sharpness is improved compared to conventional intensifying screens (the sensitivity dependence of -1 X-rays on tube voltage is also improved).

Furthermore, according to the manufacturing method of the present invention, compared to a method in which a blue-emitting phosphor layer and a green-emitting rare earth phosphor layer are sequentially laminated in this order on a support, the working time is reduced by 172 to 1/3, and the manufacturing cost is reduced. (Reduced by 7 times.)

Hereinafter, the present invention will be further explained.

The radiation image conversion screen of the present invention is manufactured by the method described below.

First, a transparent resin retaining film made of nitrified cotton, cellulose acetate, Bolier 1,000-lenonal phthalate, etc. is formed on a smooth substrate such as a glass plate or a plastic plate [7]. On the other hand, separate from this, an appropriate amount of a green-emitting rare earth phosphor for radiation, a blue-emitting phosphor for radiation having a smaller average particle diameter or specific gravity, and a binder resin such as nitrified cotton are mixed 12; Further, an appropriate amount of solvent is added to prepare a phosphor coating liquid with an optimum viscosity 12. This phosphor coating liquid is applied to the phosphor coating liquid formed in advance on a smooth substrate using a doctor blade, roll coater, knife coater, etc. Apply to the transparent resin protective film side.

The applied phosphor coating is left to dry. That is, for example, drying of a phosphor coating film is carried out at a constant room temperature for a sufficient amount of time while suppressing displacement of surrounding air. At this time, while the paint film is drying, the green-emitting rare earth phosphor particles with larger average particle size or specific gravity settle 17 in order, and the blue-emitting phosphor particles with smaller average particle size or specific gravity are pushed up 17 by convection. Therefore, there is a blue-emitting JfJ mainly composed of blue-emitting phosphor particles, a phosphor layer (10 layers) and a green-emitting phosphor layer (lower layer 1) mainly composed of green-emitting phosphor particles. In principle, Stokes' method H et al. is applied to separate the phosphor particles in the undried phosphor coating film where the phosphor layer is formed, and the sedimentation rate is determined by the phosphor particles. Since the diameter and density of the joists are large, it is natural that the blue-emitting phosphor and the green-emitting rare earth phosphor used should have a sedimentation rate of tc, 11, which is lower than the sedimentation rate of the former phosphor when Stokes' law is applied. %/7) R having a particle size and specific gravity that increases the sedimentation rate of the phosphor.
A combination of a color-emitting phosphor and a green-emitting rare earth phosphor is selected as appropriate.

Next, the phosphor layer integrated with the transparent resin retentive film is peeled off from the substrate (2, so that the blue-emitting phosphor layer side (the side opposite to the transparent resin protective film side) becomes the adhesive surface, This is heat-pressed onto a support made of paper, plastic, etc. coated with adhesive on one side.In this way, the side near the support is mainly composed of blue-emitting phosphor particles, and the surface at
A radiation image conversion screen in which a phosphor layer on the side from which light emission is taken out, that is, a transparent resin protective film (1 m) mainly consists of green-emitting rare earth phosphor particles, is provided on a support, and a transparent protective film is further provided on the support. get. In the method for manufacturing a radiation damage converting screen of the present invention, first, a phosphor coating liquid is coated on a smooth substrate L't? When drying the film, the green-emitting rare earth phosphor particles and the blue-emitting phosphor particles were not completely separated, and both were separated, resulting in a green-emitting rare earth phosphor layer and a blue-emitting layer. Although there may be slight coexistence of phosphor particles with different % light colors in the phosphor layer, in the final radiation image conversion screen,
If the phosphor layer on the support side mainly consists of a blue-emitting phosphor layer, and the 1ull 1 phosphor layer for extracting the surface AT light emission mainly consists of 12 green-emitting rare earth phosphor layers,
A blue-emitting phosphor layer and a green-emitting rare earth phosphor layer are separately formed in this order on the support 17, and the blue-emitting phosphor particles and the green-emitting phosphor particles are separated into completely separate phosphor layers. Properties similar to those of the radiation conversion screen obtained by separating the two can be obtained.

In particular, according to the manufacturing method of the present invention, when the standard deviation of the particle size of the blue-emitting phosphor is large, the particle size of the phosphor in the K-color emitting phosphor layer changes from the support side to the side of the green-emitting rare earth phosphor. As a result, a radiation image conversion screen with higher sharpness can be obtained as a result of distributing the particles with a bifurcated slope so that the particle size gradually increases toward

Furthermore, in the intensifying screen, there is also an original reflective layer such as a white pigment layer and an original absorbing layer such as a black pigment layer (some structures have a metal foil layer) between the phosphor layer and the support. However, when using the radiation damage converting screen of the present invention as an intensifying screen, if necessary, the original reflective layer and the original absorbing layer (7 or metal foil layer) are also placed on the support in advance. A phosphor layer formed separately on a smooth substrate by the method described above may be peeled off and bonded thereon.Also, in general, many radiation image converting screens are made of phosphor. A transparent resin coating is applied to M17 on the light layer, but when a transparent resin protective film is not provided, the Ti phosphor coating liquid is applied to a substrate on which no transparent resin protective film is provided, and the coating film is formed. After formation, it may be peeled off [7] and adhered to the support so that the blue-emitting phosphor layer-1 becomes the adhesive surface.

FIG. 1 shows a schematic cross-sectional view of a radiation image conversion screen manufactured by the #V manufacturing method of the present invention, in which the phosphor layer formed on the support 11 is mainly located near the support 11. and 17 are blue-emitting phosphor layers 12 made of blue-emitting phosphor particles; 14 is a transparent protective film provided on the surface of the green light-emitting phosphor N113.

The green-emitting rare earth phosphor that can be used in the method for manufacturing the radiation image converting screen of the present invention is a rare earth oxysulfide phosphor activated with terbium, which is at least one of Y, La, Gd, and Lu. , the rare earth oxyhalide phosphor (limited to phosphors in which the terbium concentration is more than j7.0.Ol mole per mole of the phosphor1), the rare earth borate phosphor, the rare earth borate phosphor, Rare earth fluorescent materials, such as phosphate phosphors and rare earth tantalate phosphors, which contain at least one of lanthanides and yttrium as a phosphor matrix constituent element and exhibit highly efficient green light emission upon X@excitation. Among these phosphors, the composition formula 1 is at least one of La, Gd, and Lu, and a and b are at least one of La, Gd, and Lu. 0.0005≦a<0.09, respectively
and 0≦b≦0.01. terbium-activated or terbium and thulium-activated rare earth oxysulfide phosphor and/or composition formula t Y+ -1-
a-b I”i.

Tbl, Tmbltols, but Ln Fi
At least one of La, Gd and Lu, and i.

a and b are respectively 065≦1≦0.95゜Q, UO
[15≦a≦0. A terbium-activated or terbium and thulium-activated rare earth fluorophore or xisulfide phosphor represented by (a number satisfying the following conditions: 19b and 0≦b≦0.Ol) is preferred.1. stomach.

The blue-emitting phosphor used in the method for producing a radiation image conversion screen of the present invention is not particularly limited as long as it emits high-efficiency blue light when excited by radiation such as X-rays. From the point of view of the sensitivity and sharpness of the radiation convergence conversion screen to be used, it is particularly practical to use the composition formula (y
, -e-d-8Gde, Tbd, Tmel, 028
′ (However, C, d and e each satisfy Q 4 c≦0
．． 60, 0.0005: i d≦0.02 and 0≦e≦0.01) Oxysulfuride ax form of yttrium or yttrium-gadolinium; compositional formula M@F' , *
pMe' X2 "qKX' a rMe" SO
4: tn h', I)", n Tb", where Me is Alg, Ca.

At least one of Sr and Ba, Me' and M
e"H (at least one of lea, Sr and Ha, X and X' are respectively 71°α and B
At least one of r, p, q, r, rn and ntmaso it U, 80 Qp≦1.5.0≦q
Th2, 0.0≦r≦1.0゜0.001≦m≦0. l
O and O≦n≦0.05); compositional formula I Ln' s -2-y-1, Tbz;
Tmy, Ybz 1OX (however, L12 is at least one of La and Gd, X is α and Br
X, 7, and 2 are each at least one of
Rare earth oxyhalide phosphor represented by 1, +105 and 0 (a number that satisfies the condition x + y); Compositional formula MIIW04 (however, (7, Ml is A4.C
A divalent metal tangununate phosphor represented by 1 which is at least one of a, & and Cd; a zinc sulfide or Fi zinc sulfide/cadmium phosphor: and compositional formula
Nb, +04 (However, I7, Ln" is La.

is at least one of Y, Gt and Lu, and Ma and W are 0≦V≦0.1 and 0≦W≦0.3, respectively
It is preferable to use at least one of rare earth tantalate or tantalum niobate phosphors represented by:゛In the method for producing a radiation image conversion screen of the present invention, the average particle diameter and quarter deviation value of the phosphor used in the blue-emitting phosphor layer are determined from the viewpoint of sensitivity and sharpness of the radiation image conversion screen obtained. The average particle size and standard deviation values are preferably 2 to 10μ and 0.20 to 0.50, respectively]2, and the more preferred average particle diameter and standard deviation values are 3 to 6μ and 0.30 to 0.5μ, respectively. 45, and on the other hand, the average particle diameter and quarter deviation value of the phosphor used in the edge color emitting phosphor layer are expressed as 9 standard deviation values of 5 to 2, respectively.
The average particle size and the 4II standard deviation value are preferably 0μ and 0.15 to 0.40 (7), and the more preferred average particle size and 4II standard deviation value are 6 to 12μ and 0.20 to 0.35, respectively.

Also, the radiation IIgI obtained in the same manner! From the viewpoint of sensitivity and sharpness of the conversion screen, the coating weight of the phosphor in the blue-emitting phosphor layer and the phosphor coating weight in the green-emitting phosphor layer are 2 to 100 K/- and 5 to 100 η, respectively.
/- is preferable 1. <, More preferably, the coating weight of the phosphor in the blue-emitting phosphor layer and the coating weight of the phosphor in the green-emitting phosphor layer are each 3 to 50 q/-.
and 20 to 80q/-. At this time, it is more preferable in terms of sharpness to make the average particle diameter of the phosphor in the blue-emitting phosphor layer smaller than the average particle diameter of the phosphor in the green-emitting rare earth phosphor layer [7 stomach.

@Figure 2 is one of the green-emitting rare earth phosphors.
1m Tbo4ss 1tot S Figure 3 shows the emission spectrum of a conventional radiation conversion screen consisting of a single phosphor layer containing only phosphors, and Figure 3 shows the emission spectrum of a radiation conversion screen obtained by the manufacturing method of the present invention. It is round, as shown in Figure 3. The radiation image converting screen has a blue-emitting phosphor layer (phosphor coating weight: 151
w/aN is BaF, a Baα, -0,1 to 0m
0.1B+a804: Green-emitting phosphor layer consisting of 0.06Eu"+ phosphor (phosphor coating type ff135'P/
cjl is' ”nJllll *Tbo, onBl, O1
S Consists of fluorophore. The curves indicated by dotted lines and chain lines in Figures 2 and 3 indicate the spectral sensitivity curve of the orthotie 1 film and the spectral sensitivity curve of the image pickup tube, respectively, which is clear from a comparison between Figures 2 and 3. As described above, the radiation image conversion screen obtained by the manufacturing method of the present invention has an emission spectrum distribution ranging from green to blue to the near-ultraviolet region, so it is different from conventional radiation consisting of a single phosphor layer made of only a green-emitting rare earth phosphor. Compared to scratch conversion NuClean, it better matches the spectral sensitivity of the OrthoTie 1 film and the photocathode of the image pickup tube, and has an M advantage particularly in terms of sensitivity.

Figure 4 shows the ratio of the phosphor coating weight of the W color emitting phosphor layer to the total phosphor coating charge of the phosphor layer in the radiation ms conversion screen obtained by the manufacturing method of the present invention. (This is an example of the relationship between the display rate 1 and the sensitivity of the radiation damage conversion screen that can be used.) The relative sensitivity on the vertical axis indicates the photographic sensitivity when combined with orthotype film
The values are expressed as relative values when the photographic sensitivity is set to 100 when no blue-emitting phosphor layer is included (consisting only of green @ original rare earth phosphor layer). Also, the song li! i! a, b,
c.

d, s and f are blue-emitting phosphor layers (Yo,
sea * Tbo, oot ItOlS phosphor layer, (Gdo, s + Yo, 4*s +
Ttlo, oos + Tmo, oot
1tots phosphor, BaF2 @Ba (J2 ・
o, xKcg L O, lBaSO4aO, 06Eu!
) Fluorescent material, l taO,1111? I Tb
o, ool 1OBr phosphor, CdWO* phosphor, and Cago phosphor. In each case, the total coating weight of the phosphor layer is 50q/-, and the green-emitting rare earth phosphor The layers are (Gdo, oss + Tbo, oos
It consists of 1t02s fluorophore.

As is clear from Figure 4, depending on the type of blue-emitting phosphor used, the sensitivity varies depending on the total phosphor coating amount.
Preferably 1. Although the ratio of coating amount of the blue-emitting phosphor layer is different, the green-emitting phosphor layer consisting of the (Gd, Tb 1ynxs phosphor) and the blue-emitting phosphor layer consisting of the blue-emitting phosphor are separated, and the green-emitting phosphor layer is separated. By providing a blue-emitting phosphor layer under the phosphor layer, a single phosphor layer consisting of only (Gd, Tb +, 0.S) elements can be formed (a green-emitting phosphor layer). It is possible to obtain a screen that has photographic sensitivity equivalent to or higher than that of a conventional radiation image conversion screen (consisting only of the following).

FIG. 5 shows the ratio (in percentage) of the phosphor coating weight of the blue-emitting phosphor layer to the total phosphor coating weight of the phosphor layer in the radiation image converting screen obtained by the manufacturing method of the present invention. Figure 5 shows the relationship between the sharpness of the obtained radiation intensity conversion screen (display) and the sharpness of the obtained radiation intensity conversion screen. The layer is (y,...,8゜'rbo, oot +
! o, s fluorophore, (cao, s, Yo, 4@I.

Tba, oos * 'rmo, 00! 1 tots
Fluorescent material, BaF2” Bac4-0.IKα@0
．． I BaSO4: 0.06Eu” Decafluorescent material (La
o, @@? I Tbo, oos 1OBr phosphor, C
The case is composed of a dWO4 phosphor and a CaWO4 phosphor, the total coating weight of each phosphor layer is 50q/-, and the green-emitting rare earth phosphor layer is l Gdo, ass *
A case of Tbo, oos ItOtS phosphor is illustrated. Also each radiation Ml! The sharpness of the image conversion screen is 1.5 for photographic density and 2 for spatial frequency.
The MTF value for the main/throat was calculated and is shown as a relative value when the MTF value of a radiation conversion screen without a blue-emitting phosphor layer (consisting only of a green-emitting rare earth phosphor layer) is set to 100. .

As is clear from FIG. 5, the manufacturing method of the present invention separates the green-emitting phosphor layer and the blue-emitting phosphor layer, and provides the blue-emitting phosphor layer below the green-emitting phosphor layer. The radiation flaw conversion screen has improved sharpness compared to the conventional one which does not have a blue-emitting phosphor layer. Figure 6 shows the radiation 51g1 conversion screen obtained by the manufacturing method of the present invention and the conventional radiation flaw conversion screen. It is a graph illustrating the X-ray tube voltage dependence of the sensitivity of the image conversion screen. In Figure 6, songs @a, b, c, d and e all have green light emitting phosphor layers (Gclo, ns + Tba, oos 1t01s
The blue-emitting phosphor layer is composed of a phosphor (Y
c+, sea I'rbo, oat +, o, s fluorophore, fluorophore FlmRap @ 0. IKαa O,lBa
804: 0.06Eu” 100% (taO, 1
1G? I Tbo, oos 1OBr Fluorescent material/C
The radiation density conversion screen of the present invention, which is composed of dWO, phosphor and CaWO+ II & element, has a coating weight of green-emitting phosphor of 30 q/cd and a coating weight of blue-emitting phosphor of 20 wq/-, The curve f indicates that the phosphor layer is l.
Gd6. o.''I'rbn,.osltotsConventional radiation wound conversion screen consisting of only phosphor+/(fluorescent coating weight is 50wII/d)(7)jji, the vertical axis in Fig. 6 is The photographic sensitivity when each radiation conversion screen is combined with an orthotype film is shown for each X-ray tube voltage. Photographs of a radiation conversion screen consisting of a single phosphor layer consisting of only CaWO4 and phosphor. Sensitivity (when combined with regular type film) is expressed as a relative value to K.

As is clear from FIG. 6, the radiation scar conversion screen obtained by the manufacturing method of the present invention has an X-ray tube voltage of 60 KVp to 140 KVp, which is used for X-ray photography during medical diagnosis.
Kvp, +7) region (Gd, Tb
1,0. The difference in X-ray tube voltage (K) causes a small 8 degree (7) change compared to the conventional radiation wound conversion nuclear ratio consisting of a single phosphor layer containing only S phosphors.

Note that the green light-emitting phosphor layer has tGd0. . 0. .

Tb o,. . , I, O, S When a green-emitting rare earth phosphor for radiation other than the phosphor is used, and in the blue-emitting phosphor layer, l Yo, ns * Tbn, oot 11028 phosphor, BaF', fist Baα, -0, IKα・0. I
Ba, SO4: 0.06 Eu” “Fluorescent material, t”
aO,1+171 Tbo,oo310Br phosphor, CdWO, phosphor, and CaWO4 phosphor When using a radiation blue-emitting phosphor other than the phosphor, Example 7r is shown in FIG.
Similar to the radiation damage conversion screen, the sensitivity of the radiation damage conversion screen obtained when the ratio of the amount of phosphor coating in the blue-emitting phosphor layer to the total amount of phosphor coating is within a specific range is green. It has a sensitivity equal to or higher than that of the conventional screen made of only a light-emitting rare earth phosphor layer, and as in the case of the radiation image conversion screen illustrated in Figure @S and Figure 6, it is made from only a green-emitting rare earth phosphor layer It was confirmed that the sharpness was improved compared to the conventional radiation image conversion screen, and the dependence of sensitivity on X-ray tube voltage was reduced.

In addition, the radiation damage conversion screen obtained by the manufacturing method of the present invention has improved photographic contrast compared to a conventional radiation damage conversion screen consisting only of a green-emitting rare earth phosphor layer17, and can also be used as a fluorescent plate for XLS televisions. Even when used, it exhibited superior characteristics, especially in terms of sensitivity and contrast, compared to conventional fluorescent plates having only a green-emitting rare earth phosphor layer [7].

In addition, from the viewpoint of graininess and sharpness of the radiation image conversion screen obtained, the radiation damage conversion screen obtained by the manufacturing method of the present invention is better than the simple pressure mixing of the green-emitting rare earth phosphor and the blue-emitting phosphor. In this way, the green-emitting rare earth phosphor particles and the blue-emitting phosphor particles in the phosphor layer are separated in the phosphor layer to form each phosphor into a separate phosphor layer, and a plurality of phosphors are formed. The one with the light body layer exhibits superior characteristics.

As described above, the radiation damage conversion screen obtained by the manufacturing method of the present invention has a sensitivity equal to or higher than that of the conventional radiation damage conversion screen consisting of only a green-emitting phosphor layer, and has a lower image quality and % However, it is possible to improve sharpness and contrast without degrading graininess.
Since the sensitivity is less dependent on the X-ray tube voltage, it has the advantage of making it easier to set the imaging conditions during X-ray imaging, and is useful as a radiation image conversion screen that provides high sensitivity and good quality images. It has great utility value.

Next, the present invention will be explained with reference to Examples. The phosphors of each set were mixed in advance at a ratio corresponding to the respective coating weights of the green-emitting rare earth phosphor layer and the blue-emitting phosphor layer (-1 part of the mixed phosphor, 8 parts of the mixed phosphor layer). and nitrified f41M (31 parts) were mixed with a solvent to form a fluorescent coating solution.

Separately, apply a coating film made of nitrified cotton uniformly on a smooth substrate to a film thickness of about 10μ] 7. After drying, apply the phosphor coating solution on top of this, total phosphor coating weight. is 501
It was coated uniformly using a knife coater so that it was 1f/CIA.

The coated phosphor coating film was dried by allowing it to stand at a constant temperature of 15°C for 10 hours while suppressing air exchange, and the green-emitting rare earth phosphor particles and the blue-emitting phosphor particles were dried. It was separated by sedimentation.

After drying, the phosphor layer integrated with the protective film made of nitrified cotton was peeled off from the substrate (7. This was coated with a carbon black light absorbing layer of 4 il+ on the surface, and a thermoplastic adhesive was applied on top of it. A 250μ thick 721) ethylene terephthalate support was heat-pressed with the side opposite to the adhesive side made of nitrified cotton serving as the adhesive surface, and the radiation #my conversion screen 1
~αQ was produced.

On the other hand, in Comparative Example and No. 17, the average particle diameter is 8, and the deviation value (quarter deviation value is 10.30, G'o, oss, Tbo,
oos 1tot3 8 parts by weight of phosphor and 1 part by weight of nitrified cotton were mixed using a solvent to prepare a phosphor coating solution.
Coat 1 on a polyethylene terephthalate support with a thickness of Oμ so that the coating weight of the phosphor is 50 wq/cli.
7. Dry using a conventional method to form a phosphor layer 12, and then apply nitrified cotton uniformly on top of the cloth (2. Dry to form a radiation GL conversion screen having a transparent protective film with a film thickness of approximately 10 μm). 1. 1. □ The radiation image conversion screen (RJ Regarding its photographic sensitivity, sharpness,
When the graininess and contrast were investigated, the results shown in the table below were obtained. All were good, with almost no low F graininess observed.

In addition, in Table 1, each radiation llIgI! The photographic performance of the conversion screen is 0rthe G Film 1 made by Kodak Co., Ltd. (-1 Photographed with X-rays at an X-ray tube voltage of 80 Kvp through a water fan dome of 803 mm. Photographic sensitivity, sharpness, It shows graininess and contrast, and each display value is displayed as the following value.

Photographic sensitivity...Displays the relative value when the photographic sensitivity of Radiation II Rin Conversion Screen I KYOKKOFS, manufactured by Kasei Aftonix Co., Ltd., which has a phosphor layer made of C1WO4 phosphor, is set to 100, sharpness.・・・・・・M at 2 spatial frequencies/w11
Find the TF value and calculate (Gdo, oos + Tbo, ooslt
Displayed as a relative value when the MTF value of a radiation image conversion screen consisting of a single phosphor layer consisting of only OtS phosphors is set to 100.

'lj7-like property...4 Displayed as an RMS value at a true density of 1.0 and a spatial frequency of 0.5 to 5.0 lines/-.

Contrast... Photographed 1■thick L and 2■thick M (also the density difference of the photographic film at the time (calculating the respective contrast from the light intensity 1). Radiation image conversion screen (KYOKKOFS).

Containers manufactured by Kasei Ogtonics Co., Ltd. Relative when trust is 100 Displayed by value.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a radiation image conversion screen manufactured by the manufacturing method of the present invention, and FIG. 2 is a graph of the emission spectrum of a conventional radiation image conversion screen. FIGS. 4 and 5 are graphs of the emission spectrum of the radiation image conversion screen obtained by the manufacturing method of the present invention, respectively, and FIGS. is a graph of relative sensitivity and relative sharpness of
The sixth factor is a graph of the X-ray tube voltage dependence relative sensitivity of the radiation image converting screens obtained by the present invention and the conventional manufacturing method. Engraving of the drawing (no changes to the content = L) Figure 1 Yan Station 4 Station Prison Level 4 Yan Mi Ith 12 Kagegi Seal Procedures Amendment Book June 9, 1985't! 1. ",'Yn'1<+", lk EB Spring 114 Punishment 1 °IX I'1 Shown *si No. 57-79437 2 Invention 1, Method of manufacturing radiation image conversion screen 3 Person making correction Relationship to the case Patent applicant name Kasei Odetonics Co., Ltd. 4th generation PF person fl-, location 2-8-1 Toranomon, Minato-ku, Tokyo Toranomon Electric Vehicle Drawing 6 Contents of the Amendment The engraving in 1. is supplemented as shown in the attached sheet. Procedural Amendment September 161-1 Director General of the Patent Office Kazuo Wakasugi 1 Special Indication of the Case - No. 1987-79437 2 Name of the Invention Method for Manufacturing a Radiation Image Conversion Screen 3 Person Making the Amendment Relationship to the Case Patent applicant name: Kaga Odetonics Co., Ltd. 4 Agent: 6 Contents of amendment: The scope of the samurai license request is corrected as shown in the attached sheet. (2) Ming! gB$20, line 18, "Tantalum salt phosphor, etc." is corrected as follows. “Tantarate fluorescer, Sokidoken oxysulfide fluorescer co-activated with at least one of the rare earth elements such as terbi9 and thulium, dysprosium, ! raceosome, ytterbium, neosim, etc. Jl: Tatsu In the 21st picture, line 10 and lines 17 to 18, line 1, "thulium activation" is corrected to "thulium co-activation". 141 "and/or" in the 21st picture, line 11
t Corrected to ",". 15) In the 18th line of the 21st article, ``The fluorescent material is good'' should be corrected as follows. "Fluorescent material, compositional formula (Lm, -, -6, Tb, , Rb
) BOMB (However, Lm is La, Gd and L-
R is at least one of dysprosium, delaseosome and ytterbium, and a and b are 0.0005≦a≦0.09 and 0.0005≦b≦0.01, respectively. A rare earth co-activated rare earth oxysulfide phosphor and a composition formula ' Yl -1-a -b
tLnit 'rb, I Rb) sows (However,
Ln is Lm. At least one of Gd and Lu, R is one of dysprosium, delaseosome and ytterbium (
19 prefectures and b are each 0.65≦
i≦0.95゜0.0005≦a≦0.09 and 0.
0005≦b≦0.01) (6) Specification A, page 133, line 5, “Y indicated. Insert the following after ``. ``Also, since the radiation image converting screen obtained by the manufacturing method of the present invention includes a slight blue component in the light emitted from the upper fabric color light-emitting rare earth phosphor layer having a blue@light phosphor layer, it is a Reginilla type. In combination with X-ray film, it showed excellent properties. Each “~1
13". (8) "10 groups 1'r13 groups" on the 20th line of the same @ 33 hundred
K Correct. (9) Correct “rlO樗＄” in line 18 of No. 35 Rooster to “13 types.” jll rso cut of 11th line of 36th race”vr80
There is also a correction Ef in “Ryu”. Add the following table under uu 1ctl No. 386. Claims: (1) Green-emitting rare earth phosphor particles for radiation and blue-emitting phosphor particles for radiation having a smaller average particle diameter or specific gravity are dispersed in a binder resin. A phosphor coating liquid is applied onto a transparent resin protective film that has been previously formed on a smooth substrate, and the green luminescent rare earth phosphor particles for radiation are formed by drying the phosphor coating solution by allowing it to stand still (17). 17. After forming a separate phosphor layer from the radiation blue-emitting phosphor particles, the phosphor layer integrated with the transparent resin protective film is peeled off from the substrate to remove the phosphor. By adhering to the support such that the layer side (the side J opposite to the transparent resin protective film side is the adhesive surface), a phosphor layer consisting of the blue emitting phosphor for radiation is mainly formed on the support at 17 and 17. , Lord and (
7. A method for producing a radiation image conversion screen, which comprises obtaining a radiation image conversion screen in which a phosphor layer made of the green-emitting rare earth phosphor for radiation and the transparent resin protective film are laminated in this order. (2i) The green light-emitting rare earth phosphor for radiation has a compositional formula (%) (However, (7, Ln is at least one of La, Gd, and Lu, and a and b are each 0.0005≦a
≦0.09 and 0≦b≦0.01) and /
Still, the compositional formula %formula%
≦0.95, 0.0005≦a≦0.09 and 0
≦b≦0. The method for manufacturing a radiation image conversion screen according to claim 1, characterized in that the screen is a rare earth oxalphaide phosphor represented by: (3) The W color emitting phosphor for radiation is one of the following (1) to (
3. The method for producing a radiation image converting screen according to claim 1 or 2, wherein the phosphor is at least one of the phosphors represented by V). (1) Compositional formula (Yl-c-d-eGdcTbdTme+
2028 (however, 17, c, d and e are each 0≦C≦
0.60, 0.0005≦d≦0.02 and 0≦
An oxysulfide phosphor of yttrium or yttrium-gadolinium expressed as (a number that satisfies the condition e≦0.01), (111 compositional formula MoF3・rM′eX2・qKX′・
rM″eS04: mEu”, nTb” (However, Me is at least one of Mg, Ca, Sr and Ba, M'e and M”e are each Ca
, Sr and Ha, X and X' are each at least one of α and Br, and p+Q+r+m and n are each 0.80≦p≦
1.5.0≦q≦2.0. an alkaline earth metal composite halonide phosphor represented by J, which is a number satisfying the following conditions: 0≦r≦1.0, 0.001≦m≦0.10, and 0≦n≦0,05; iii+ Compositional formula (L%'(-x-y -1, T
bz,Trny. b210X (However, (7, Lv? is at least 1 of La and Gd)
and X is at least one of α and Br.
x, y and 2 are each 0≦X≦0.01.0≦y≦
0.01, 0≦2≦o, oos and 0 (x + y
A rare earth oxyhalide phosphor is a number satisfying the following conditions: (1v) Compositional formula M"WO.
A divalent metal tungstate phosphor represented by at least one of d,
However, zinc sulfide or zinc sulfide cadmium phosphor represented by (~, j is a number satisfying the condition 0≦"≦0.4, and (■1) compositional formula (-ton, -7Tmvl (Ta+ −
L. NbWIO. (However, L%" is at least one of La, Y, Gd, and Lu, and V and W are each O≦V≦
0.1 and 0≦W≦0.3) A rare earth tantalate or tantalum niobate phosphor. (4) The average particle diameter of the phosphor in the blue-emitting phosphor layer for radiation, its standard deviation value (-minute deviation value), and the coating weight of the phosphor are 2 to 10 μm, 0.20 to 0.50 μ, and 0.20 to 0.50, respectively. 2
~100 ■/d, and the average particle diameter of the phosphor in the green-emitting rare earth phosphor layer for radiation use, its standard deviation value (quarter deviation value; and the coating weight of the phosphor are 5 to 20μ, respectively
0.15 to 0.40 and 5 to 11001n/Crl. Method for manufacturing the radiation image converting block 11-e according to the scope of the patented building block, item 1, item 2, or item 3.
0 (5) The average particle diameter of the phosphor, its standard deviation value (quartile deviation value), and the coating weight of the phosphor in the blue light-emitting phosphor layer for radiation are 3 to 6 μ0.30 to 0.45 and 3, respectively. ~5
0■/d, and the green light-emitting rare earth phosphor for radiation
- average particle diameter, its standard deviation fi! E (quarter deviation value) and phosphor coating weight are 6 to 12μ and 0.2, respectively.
0 to 0.35 and 20 to 80 mg/CIl, the method for producing a radiation image conversion screen according to item 4 of the patent application.

Claims (5)

[Claims] (1) A phosphor coating liquid made by dispersing green-emitting rare earth phosphor particles for radiation use and blue-emitting phosphor particles for radiation use with a smaller average particle diameter or specific gravity in a binder resin, The green-emitting rare earth phosphor particles for radiation and the blue-emitting fluorescein for radiation are coated on a transparent resin preservation film formed in advance on a smooth substrate and left to dry. form a phosphor layer separated from the body particles 1
7.17 After that, the phosphor layer integrated with the transparent resin protective film is peeled off from the substrate, and the phosphor layer side (the side opposite to the transparent resin protective film side) is the adhesive surface. A phosphor layer mainly consisting of the blue-emitting rare earth phosphor for radiation, and a phosphor layer 17 mainly consisting of the green-emitting rare earth phosphor for radiation on the support. A method for producing a radiation conversion screen, characterized in that the layers and the transparent resin protective film are laminated in this order to obtain a nine radiation conversion screen. (2) The green-emitting rare earth phosphor for radiation has a composition formula % (However, Ln #'iLm is at least one of Gd and Lu, and a and bu are o, oo, respectively.
os≦breath≦0.09 and 0≦b≦0.01)
or composition formula % formula % (however, Ln is at least one of La, Gd and Lu, and 1.1 and b are each 0.65≦i≦
0.95, 0.0005≦a≦0.09 and 0≦
b≦0. The method for producing a radiation scar conversion screen according to claim 1, characterized in that the phosphor is a rare earth oxysulfide phosphor represented by J, which is a number that satisfies the condition: Ol. (3) The blue-emitting phosphor for radiation is one of the following to (!1)
3. A method for producing a radiation damage conversion screen according to claim 1 or 2, characterized in that the phosphor is at least one of the phosphors represented by /S. 111 Compositional formula (Y, -cd-s GdcTbdT
m@110HS (12, e, d and e are each 0
≦C≦0.60, 0.0005≦d≦0.02, and 0≦・≦0, Ol) Oxysulfide phosphor of yttrium or yttrium self-gadolinium, tiil composition formula MeFl @rM'sX2 ・q
KX'・rM"esO4:mEu",n'i'b
” (However, M@Id 4 * Ca, 8r and B
*Pa in &, at least one, M's and M″@ respectively C&,
At least one of Sr and B&, X and X'
are each at least one of α and BrO,
1'+Q*r*ffl and n are each 0.80≦p
≦1.5.0≦q≦20゜0≦r≦1.0, 0.00
Alkaline earth platform
Composite halide phosphor, +iiH compositional formula i L'n, -, -, -,, Tbx,
Tm. Yb, l0X (however, L'n is at least one of La and Gd, X is at least one of α and Br, x,
y and 2 are respectively 0≦X≦0゜01.0≦y≦0.
01.0≦2≦o, oos and 0 (x + y
A rare earth oxylognide phosphor represented by 1, which is a number that satisfies the following conditions:
divalent metal tungsten-Sunshio phosphor represented by (at least one of d)
Ay (where 1~, j is a number satisfying the condition 0≦j≦0.4) Zinc sulfide represented by J is a zinc sulfide cadmium phosphor, and +yi+ Compositional formula I L//n, -, , Tm, I
(Tag. ≦W≦0, 3) A rare earth tantalate or tantalum niodate phosphor. (4) The average particle diameter of the phosphor in the blue-emitting phosphor layer for radiation, its standard deviation value (quarter deviation value 1 and phosphor coating weight are 2 to 10 μm, 0.20 to 0.50 μm, and 0.20 to 0.50 μm, respectively) 2
~100 q/cli, and the average particle diameter of the phosphor in the green-emitting rare earth phosphor layer for radiation use and its standard deviation value t
&! Ij minute deviation value) and phosphor coating weight are 5 each.
~20μ, 0.15~0.40 and 5~100■/
- Claim 1 JJi,
A method for manufacturing a radiation image conversion screen according to item 2 or 3. (5) The average particle diameter of the phosphor in the blue-emitting phosphor layer for radiation, its standard deviation value (quarter deviation value r and coating weight of the phosphor are 3-6μ0.30-0.45 and 3-6μ, respectively)
50"F151, and the average particle diameter of the green light-emitting rare earth phosphor layer for radiation use, its standard deviation value (quarter deviation value i, and phosphor coating weight are 6 to 12μ and 0.20 to
0.35 and 20 to 8011f/cd, the method for producing a radiation density conversion nucleus according to claim 4.