JPS61142498A - Radiation image conversion panel and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a radiation image conversion panel using a stimulable phosphor, and more particularly to a radiation image conversion panel that provides a highly sharp radiation image and a method for manufacturing the same.

[Prior art]

Radiographic images such as X#i images are often used for disease diagnosis. In order to obtain this X-ray image, X-rays that have passed through the subject are irradiated onto a phosphor layer (fluorescent screen).
This generates visible light, which is then irradiated onto a film using silver salt to develop it, in the same way as when taking ordinary photographs, in what is called radiography. However, in recent years, methods have been devised to directly extract images from the phosphor layer without using a film coated with silver salt. In this method, the radiation transmitted through the object is absorbed by a phosphor, and then this phosphor is excited with light or thermal energy, so that the phosphor emits the radiation energy accumulated through the absorption as fluorescence. There is a method of detecting this fluorescence and creating an image. Specifically, for example, U.S. Pat.
No. 5-1214'4 discloses a radiation image conversion method using a stimulable phosphor and using visible light or infrared rays as stimulable excitation light. This method uses a radiation image conversion panel in which a stimulable phosphor layer is formed on a support, and radiation that has passed through the object is applied to the stimulable phosphor layer of this radiation image conversion panel to visualize various parts of the object. A latent image is formed by accumulating radiation energy corresponding to the radiation transmittance, and then this stimulable phosphor layer is scanned with stimulable excitation light to radiate the accumulated radiation energy in each part. An image is obtained by converting the light into light and using an optical signal based on the intensity of this light. This final image can be reproduced as a notebook copy or on a CRT.
1. Now, the radiation image conversion/layer having a stimulable phosphor layer used in this radiation image conversion method has radiation absorption rate and light conversion similar to the case of radiography using a fluorescent screen described above. It goes without saying that the radiation sensitivity (hereinafter referred to as "radiation sensitivity") is high, 111, and that the image has good graininess and high sharpness. However, in general, a radiation image conversion panel having a stimulable phosphor layer is prepared by dispersing a dispersion containing a particulate stimulable phosphor with a particle size of about 1 to 30μ and an organic binder on a support or a protective layer. Since it is formed by coating and drying, the packing density of the 111[N-type phosphor is low (filling rate 50%). It was necessary to increase the thickness of the phosphor layer. As is clear from the figure, the thickness of the stimulable phosphor layer was 200 μm.
At the same time, the adhesion resistance of the stimulable phosphor is 50g7cm'', and the radiation sensitivity increases linearly until the layer thickness reaches 350μ, and is saturated at 450μ or more. This is because if the stimulable phosphor layer becomes too thick, the stimulable phosphor layer will not be able to emit the stimulable luminescence to the outside due to scattering of the stimulable phosphor particles between the stimulable phosphor particles. On the other hand, as shown in FIG. 6(b), the image sharpness in the radiation image conversion method tends to be higher as the thickness of the stimulable phosphor layer of the radiation image conversion panel becomes thinner. In order to improve sharpness, it was necessary to make the stimulable phosphor layer thinner. In addition, the graininess of the image in the radiation image conversion method is caused by local fluctuations in the number of radiant weight molecules ( It is determined by the structural disorder (structural mottle) of the photostimulable phosphor layer (quantum mottle) or radiation image conversion (fine layer), so as the layer thickness of the stimulable phosphor layer becomes thinner, the The number of radiation quantum forces C absorbed by the phosphor layer decreases, resulting in an increase in quantum mottles, and structural disturbances (t) increase, resulting in an increase in structural mottles, resulting in a decrease in image quality. In order to improve the performance, the layer thickness of the stimulable phosphor layer had to be -1.In other words, as mentioned above, the conventional radiation 1 image conversion l<N is the sensitivity to radiation and the image The graininess and image sharpness of the stimulable phosphor layer depend on the layer thickness of the stimulable phosphor layer. By the way, it is well known that the sharpness of images in conventional radiography is determined by the spread of instantaneous light emission (light emission during radiation irradiation) of the phosphor in the fluorescent screen. However, on the other hand, the radiation image conversion method using the stimulable phosphor mentioned above: (i.e., it is not determined by the spread of the phosphor emission as in radiography, but depends on the spread of the stimulated excitation light within the panel. In the radiation image conversion method, since the radiation image information stored in the radiation image conversion panel is retrieved in a time-series manner, all of the stimulated luminescence due to the stimulated excitation light irradiated at a certain time (ti) is desirably removed. It is recorded as the output from a certain pixel (X!tyi) on the panel that was illuminated with light and stimulated excitation light at that time, but if the stimulated excitation light spreads within the panel due to scattering etc. This is because if the stimulable phosphor existing outside the pixel (xityi) is also excited, the output from the pixel (xityi) will be recorded from a region wider than that pixel. Therefore, for a certain time (
The shine radiated on ti)! - If the stimulated luminescence caused by excitation is only the luminescence from the pixel (xLy+) on the panel that was truly irradiated with the stimulated excitation light at that time (ti), what kind of spread does the luminescence have? There is no effect on the sharpness of the image obtained. Under these circumstances, several methods have been devised to improve the sharpness of radiographic images. For example, JP-A-55-1
Method of incorporating white powder into the stimulable phosphor layer of a radiation image conversion panel described in No. 46447, JP-A-55-163
The radiation a image conversion panel described in No. 500 is colored so that the average reflectance of the stimulable phosphor in the stimulated excitation wavelength region is smaller than the average reflectance of the stimulable phosphor in the stimulated emission wavelength region. Method etc'. However, in these methods, improving the sharpness inevitably leads to a drastic decrease in sensitivity, and therefore cannot be said to be a preferable method. On the other hand, the present applicant has already filed a patent application for
As a novel radiation image conversion panel that improves the conventional drawbacks of the radiation #I image conversion panel using 7 photostimulable phosphors as described above in No. 6365, the stimulable phosphor layer does not contain a binder. We are proposing a radiation image conversion panel. According to this, since the stimulable phosphor layer of the radiation image conversion panel does not contain a binder, the filling rate of the stimulable phosphor is significantly improved, and the transparency of the stimulable phosphor layer is improved. Therefore, the sensitivity of the radiation image conversion panel to radiation and the graininess of the image are improved, and at the same time, the sharpness of the image is also improved. However, in the radiation image conversion method, the sensitivity,
The demand for image quality with excellent sharpness without impairing graininess is becoming ever more stringent. OBJECTS OF THE INVENTION The present invention relates to the above-mentioned proposed radiation mma conversion panel using a stimulable phosphor, and further improves the same.
SUMMARY OF THE INVENTION An object of the present invention is to provide a radiation image conversion panel that has improved sensitivity to radiation and provides images with improved sharpness. Another object of the present invention is to provide a radiation image conversion panel that has improved graininess and provides images with high sharpness. Another object of the present invention in addition to the above object is to provide a method for manufacturing a radiation image conversion panel that satisfies the above object.

[Structure of the invention]

The object of the present invention is to provide a radiation image conversion panel having a stimulable phosphor layer on a support, which has a surface structure in which a large number of micro tile-like plates are laid out and separated from each other by minute gaps. and a stimulable phosphor layer having a fine columnar block structure inheriting the surface structure as it is on the support, and a method for producing the radiation image conversion panel. achieved. That is, in the radiation image conversion panel of the present invention, the surface of the support is approximately 1 to 400 μI separated from each other by gaps in the form of cracks, grooves, or depressions having a width of 0.01 to 20 μ.
The stimulable phosphor layer is formed on the micro tile-like plates;
It is made up of fine columnar blocks separated from each other with the gap left deep in the thickness direction. Due to such optically independent additions, the stimulable excitation light incident on the stimulable phosphor layer is totally reflected within the fine columnar blocks 1177, and is hardly dissipated in the lateral direction, and is directed toward the support. and move only in the vertical direction. In particular, because the gaps on the support surface are left as they are in the photostimulable phosphor layer, the fine columnar blocks forming the photostimulable phosphor layer are optically completely independent of each other, allowing photostimulable excitation to occur. There is very little lateral dissipation of light. Therefore, without increasing the opportunity for photostimulation, the sharpness of images due to stimulated emission can be significantly increased. For forming a stimulable phosphor layer having a fine columnar block structure, vapor deposition methods such as vacuum evaporation and sputtering are preferred from the viewpoint of sensitivity and technical aspects of forming columnar blocks. Further, as a support having a surface structure in which a large number of micro tile-like plates surrounded by minute gaps are spread, it is preferable to use a support made of an anodized aluminum plate subjected to a sealing treatment and subsequent heat treatment. A manufacturing method using this support is useful. Next, the present invention will be specifically explained using embodiments. FIG. 1(a) is a cross-sectional view taken in the thickness direction of a radiation image conversion panel (hereinafter sometimes simply referred to as a panel for clarity) showing an example of an embodiment of the present invention. The same figure (b) shows a support having a surface structure in which the micro tile-like plates are separated from each other by micro gaps, and are not yet provided with the stimulable phosphor layer having the micro columnar block structure. FIG. 3 is a cross-sectional view of the body in the thickness direction. The distribution pattern of the micro tile-like plate on the support may be arbitrary. FIG. 2 shows examples (a), (b), and (c) of the distribution pattern of the micro tile-like plates. Note that the same symbols in FIGS. 1 and 2 are functionally synonymous with each other. In FIG. 1, 10 is the panel of the present invention, 1lij is each micro tile-like plate on the support surface, and (Ilij) is a crack, groove, depression, etc. surrounding the micro tile-like plate. It is a gap. Reference numeral 11 denotes a distribution pattern layer of minute tile-like plates dispersed in the form of islands on the surface of the support made of the above-mentioned 11ij and (llij). 12 is a support. 13ij is each fine columnar block of stimulable phosphor deposited on the micro tile plate by vapor deposition method, (13i
j) is a deep gap left between 13ij selectively deposited on 1lij. 14 is an adhesive layer that may be provided if necessary, and 15 is a protective layer that is preferably provided. The stimulable phosphor layer 13 having a fine columnar block structure according to the present invention is formed by 13ij and (13i, j). Note that the gap (13ij) referred to in the present invention includes a case in which a mere crack is formed without providing a substantial gap on the surface of the stimulable phosphor layer. Contains. As an example of the pattern of the minute tile-like plates 11ij and minute gaps (llij), FIG. 3 shows the slopes of an aluminum plate support which has been anodized, sealed and heat treated. Similar to the adhesive layer 14, a multilayer structure may be provided on the micro tile plate 11ij, such as a reflecting layer or an absorbing layer for stimulated luminescence and/or stimulated excitation light, if necessary. The thickness of the stimulable phosphor layer 13 of the panel of the present invention varies depending on the sensitivity of the panel to radiation, the type of stimulable phosphor, etc., but is preferably in the range of 10 to 1000 μm, and more preferably 20 to 800 μm. It is preferable. In the radiation image conversion panel of the present invention, the stimulable phosphor refers to a stimulable phosphor that is irradiated with a priori, thermal, mechanical, chemical, electrical, etc. after being irradiated with the first light or energy radiation. 1k (photostimulation excitation) causes the first light or high-energy radiation to shine! It refers to a phosphor that exhibits stimulated luminescence corresponding to the amount of #, but from a practical standpoint, it is preferably 500+e*
Examples of the stimulable phosphor used in the radiation image conversion panel of the present invention include BaSO4 described in JP-A-48-80487: AX (However, A is the lesser of Dy+Tb and T spear (both are 1 type, X is 0.0 old ≦×〈
It is 1 mol%. ) Phosphor expressed by JP-A-1988-8
MgS O4:A X (however, A is Ho) described in No. 0488
Or which one of Dy is 0.001≦X≦1
Phosphor expressed as mol%), JP-A-48-804
Written in issue 89! 5rSQ4:Ax (However, A is at least one of D y t T b and Tn +
species, and X is 0.001≦x<1 mol%. ), a phosphor in which at least one of Mn+Dy and Tb is added to NazSO, Ca5O, Ba5O<, etc. described in JP-A-51-29889; - Be described in No. 30487
O+ L i F M g SO Phosphors such as O4 and CaF2, L described in JP-A-53-39277
izB 40 t: Phosphors such as cu*Ag, JP-A-5
Lizo ・(B
202) X: CLl (where X is 2<x≦3), and L
Phosphors such as i20 ・(B 202)
SrS described in No. 27: Ce, Ss, SrS:
Eu, Sn+, Ll1202S: Eu, STI and (
Examples include phosphors represented by Zn, Cd)S:Mn,X (where X is a halogen). Also, JP-A-55-1
ZnS:Cu, Pb phosphor described in No. 2142, barium aluminate phosphor whose general formula is represented by B ao ・XA 1203: E u (however, 0.8≦X≦10), and the sea shell type M”O・χS io 2:A (
However, Ml is MgpCa, Sr, Zn, Cd, or Ba, A is at least one of Ce-Tb-Eu-T+n-Pb, TI, Bi, and Mn, and × is 0.5≦X≦
It is 2.5. ) are alkaline earth metal silicate base phosphors. 'Mana, the general formula is (Ba Mg Ca)FX: eEu''
1-xy x y (where X is at least one of Br and CI,
×, y and e are respectively O<x+y≦0.6, xy; l
' This is a number that satisfies the following conditions: 0 and 10-6≦e≦5X10-2. ) is the general formula represented by L no X : xA (where Ln is at least one of LatY, Gd and Lu,
b is a number satisfying O<x<'0.1), the general formula described in JP-A-55-12145 is (where Ml is v Ca w S r * Z
at least one of n and Cd, X is CI, B
at least one of r and I, A is Eu, Tb, C
e, Tm, DytPrtHovNd, Yb, and E (X and y represent numbers satisfying the conditions 0≦X≦0.6 and 0≦y≦0.2.) The general formula of the phosphor described in JP-A-55-84389 is B a F X :xCezYA (where X
is at least one of CI, Br and I, A is In
, TI', Gd, S and Zr, and x and y are 0x≦2X10-' and o<y≦5X1G-2, respectively. ); the general formula described in JP-A-55-160078 is M
”FX-xA:yLn (However, Ml is at least one of MgtCatBa+5rtZn and VCd, A is B e O? M g 0
1 Ca O+ SrO, BaO, Z nO, A I
203-Y 203. L 11201. InzOit
s io ztT +02vZ ro 2yG eo
2=s no 2. Nbz05, Ta2o5 and TI
+02, Ln is EutTbvC
etTmtDy, Pr, l-1o, Nd, Yb, Ert
is at least one of SIIl and (/Gd, and
is at least one of C1, Br and ■, and
and y are s x 1o-5≦x≦0.5 and o, respectively
It is a number that satisfies the condition '<y≦0.2. ) rare earth element-activated divalent metal fluorohalide phosphor, the general formula is ZnS:A%CdS:A, (Zn, Ccl)
Phosphors represented by S: A, ZnS: A, X and CdS: A,
General formula (1) or (II) described in No. 8285
, General formula (I) xM3(PO4)2''NX2:
YA general formula (II) Mz(PO-)2・yA
(In the formula, M and N are each M g+ Cat S r
tB At least one of alZn and Cd, X is F, CI. At least one of Br and ■, A is E ut T
b. CetTm, DytP rtHotN dtE rts
bvT l*6 representing at least 61 types of Mn and Sn. Furthermore, X and y are numbers that satisfy the condition 0<x≦6.0≦y≦1. ), a phosphor represented by the general formula (I
II) or [■] General formula (m ) hReXs・m
AX' 2:xEu general formula (W) nReX=・
mAX' 2:XEuwySl* (where Re is Lav
At least one of GdyY and Lu, A represents an alkaline earth metal, at least one of Ba*Sr and Ca, and X and X' represent at least one of F=CI and Br. Also, X and y are 1xto-'<x<3 XIG
-', IX10-'<y<IX10-', and n7m is IX10-'<
The condition n7m<7×10-' is satisfied. ), and the general formula % formula %: (However, MX is at least one kind of alkali metal selected from Li, Na, Rh, and Cs; Mx,
is B ev-Mg* Cat S rt B at Z
n* Cdv At least one divalent metal selected from Cu and (7Ni. Ml is Sc, Y, La, C
e, Pr, Nd, P@, Ss, Eu, Gd, Tb. DytHotErtTmtYbtLusAI*Gat and (/In) is at least one kind of trivalent metal selected from X. X' and X# are at least one kind of halogen selected from FtCltBr and TmtDytPrtHotNdtYbtErtG
d, Lu, SmtY * T l t N a t A
g v At least one metal selected from Cu and Mg. Also, a is a numerical value in the range of 0≦a<0.5, and b is 0≦
b is a numerical value in the range of <0.5, and C is a numerical value in the range of 0<c≦0.2. ) and the like can be mentioned. In particular, alkali halide phosphors are preferred because they facilitate the formation of a stimulable phosphor layer by methods such as vacuum evaporation and sputtering. However, the stimulable phosphor used in the radiation image conversion panel of the present invention is not limited to the above-mentioned phosphor,
Any phosphor may be used as long as it exhibits stimulated fluorescence when irradiated with radiation and then irradiated with bright N-excitation light. The radiation image conversion panel of the present invention may be a stimulable phosphor layer group consisting of one or more stimulable phosphor layers containing at least one kind of the above-mentioned stimulable phosphors. Furthermore, the stimulable phosphors contained in each stimulable phosphor layer may be the same or different. In the radiation image conversion panel of the present invention, any support may be used as long as it has a surface structure in which a large number of micro tile-like plates are laid out and separated from each other by minute gaps. Molecular materials, positive metals, etc. are used. In particular, materials that can be processed into flexible sheets or webs are suitable for handling as information recording materials, and from this point of view, for example, cellulose acetate films, polyester films, polyethylene terephthalate films, polyamide films, polyimide films, and reacetate films. . Plastic films such as polycarbonate films,
A metal sheet such as aluminum, iron 1 M 1 chromium, or a metal sheet having a coating layer of the metal oxide is preferable. The layer thickness of these supports varies depending on the material of the support used, but is generally 80 μff1 to 1000 μ-
From the viewpoint of handling, it is more preferably 80 μm to 500 μm. In the radiation image conversion panel of the present invention, a protective layer for physically or chemically protecting the stimulable phosphor layer group is generally provided on the surface where the stimulable phosphor layer is exposed. It is preferable to provide one. This protective layer may be formed by directly applying a protective layer coating liquid onto the stimulable phosphor layer, or by adhering a separately formed protective layer onto the stimulable phosphor layer. A good material for the protective layer is cellulose acetate. Common protective layer materials such as nitrocellulose, polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene chloride, polyethylene, vinylidene chloride, and nylon are used. In addition, this protective layer can be formed by vacuum evaporation, sputtering, etc.
It may be formed by laminating inorganic materials such as SiC, Sio□-8iN tAlzos, etc. The thickness of these protective layers is generally 0.1μ- to 100μ-
degree is preferred. Next, a method for manufacturing the panel of the present invention will be explained. In the present invention, the manufacturing process proceeds in the order of (b)→(,) in FIG. 1. Step (b): Micro tile-like plate 11ij and gap (lli
j) Distribution pattern The surface of the micro tile-like plate distributed on the surface of a support such as a plastic film, metal sheet, or metal sheet having a metal oxide coating layer is the stimulable phosphor deposited thereon in the previous step. It is preferable that the material has good adhesion affinity with the material, and it may be preferable that the material is a dielectric or a semiconductor that has electrical image fastness. Therefore, one method selected is to apply various resist resins commonly used in photolithography that meet the above conditions and can form the above distribution pattern on the surface of the support. At this time, it is convenient to use a metal sheet having a metal oxide coating layer as the support because it has good adhesion affinity with the resist resin. Techniques for laminating metal oxides on metal surfaces are commonly used in technical fields such as coating, spraying, or chemical vapor deposition (CVD).
Physically, an RF ion plating method, an RF sputtering method, a vacuum evaporation method, or the like can be used. As the resist resin, various positive type and negative type resist resins such as 7-oscilloscope resist, deep ultraviolet resist, electron beam resist, and X-ray resist can be used. For example, photorenost resins include those obtained by subjecting 7-bora-tsuku resin to an esterification reaction with solutoquinone azide or penzoquinone anode. First, the resist resin is applied to the support, a micro tile-like plate pattern is baked, developed, and etched using a wet or dry method to a depth where the surface of the support is exposed. Distribution pattern layer 1 woven by
1 is obtained. In addition, when using an aluminum plate as a support in addition to the photolithography method using the above-mentioned resist resin, it is possible to easily form microscopic particles by sealing the porous aluminum oxide generated on the surface by anodizing, followed by heat treatment. It is possible to create a distribution pattern (turn) in the tile-like plate. The method applied to the present invention is a method commonly used in the field of aluminum surface treatment technology. First, the anodizing treatment of the surface of the aluminum support is performed by, for example, 0. When the side of an aluminum plate having a thickness of about 5111I11 on which the stimulable phosphor is to be subjected to tS deposition is energized at IA/am2 for about 2 hours in an 8% oxalic acid solution, an anodic oxide film layer made of porous aluminum oxide is formed. Next, the coating layer is washed with water and then boiled in boiling water for about 1 hour, and the porous aluminum oxide takes in crystal water and expands to form a coating layer consisting of m-dense crystals. This operation is so-called. This is a sealing treatment. When heat treatment is performed at 250°C or higher after the sealing treatment, the aluminum oxide containing the crystal water loses the crystal water and shrinks, and is surrounded by gaps created by cracks due to shrinkage and separated from each other. A putter is formed in which the aluminum oxide coating has a thickness of several micrometers or more, and if it is thin, the microtile plates tend to become large, so the anodic oxidation process is In this way, the island-like fine sections (tile-like plates) that are physically and/or chemically favorable to the vapor phase ik product of the stimulable phosphor are It is difficult to progress and a distribution pattern layer surrounded by fine streaks, grooves, recesses or cracks is obtained.Step (a): Stimulable phosphor layer 13 The stimulable phosphor layer 13 has a fine columnar block structure. As a method for forming the phosphor layer, vapor phase deposition is most preferable from the viewpoint of reliability and sensitivity in forming the columnar blocks, and the first method of the +11° vapor phase deposition method is vacuum evaporation. In this process, the support is first placed in a vapor deposition apparatus, and then the apparatus is evacuated to a degree of vacuum of about 10-6 Torr.Next, at least one of the stimulable phosphors is heated by a resistance heating method, The stimulable phosphor is deposited on the surface of the support to a desired thickness by heating and evaporating it using a method such as an electrobeam method.As a result, a stimulable phosphor layer containing no binder is formed, but It is also possible to form the stimulable phosphor layer in multiple steps in the vapor deposition process.Also, in the vapor deposition process, it is also possible to co-evaporate using a plurality of resistance heaters or electrobeams. . After the vapor deposition is completed, a protective layer is optionally provided on the side of the stimulable phosphor layer opposite to the support, and the radiation image conversion panel of the present invention is manufactured. Note that a step may be taken in which the support is provided after forming the stimulable phosphor layer on the protective layer. In addition, in the vacuum evaporation method, the stimulable phosphor raw material is codeposited using a plurality of resistance heaters or an electron beam, and the desired stimulable phosphor is synthesized on the support while the stimulable phosphor is simultaneously evaporated. It is also possible to form a phosphor layer. Furthermore, in the vacuum evaporation method, the object to be evaporated (support or protective layer) may be cooled or heated as necessary during the evaporation. Further, the stimulable phosphor layer may be heat-treated after the vapor deposition is completed. A second method is a sputtering method. In this method, like the vapor deposition method, the support is placed in a sputtering device, the inside of the device is once evacuated to a vacuum level of about 10-' Torr, and then a non-containing gas such as Ar or Ne is used as a sputtering gas. Introducing active gas into the sputtering equipment to generate 1O-3T o
The gas pressure is set to about rr. Next, the stimulable phosphor is deposited on the surface of the support to a desired thickness by sputtering using the stimulable phosphor as a target. In the sputtering process, it is possible to form the stimulable phosphor layer in multiple steps as in the vacuum evaporation method, or it is possible to form the stimulable phosphor layer in multiple steps at the same time by using multiple targets each made of a different stimulable phosphor. Alternatively, it is also possible to sequentially sputter the targets to form a stimulable phosphor layer. After the sputtering is completed, a protective layer is preferably provided on the side of the stimulable phosphor layer opposite to the support, if necessary, in the same manner as in the vacuum evaporation method, and the radiation M image conversion panel of the present invention is manufactured. Note that a step may be taken in which the support is provided after forming the stimulable phosphor layer on the protective layer. In the sputtering method, a plurality of stimulable phosphor raw materials are used in a tarded manner, and these are sputtered simultaneously or sequentially to synthesize the desired stimulable phosphor on a support and simultaneously produce the stimulable phosphor. It is also possible to form layers. Furthermore, in the sputtering method, reactive sputtering may be performed by introducing a gas such as 0□ or H2 as necessary. Furthermore, in the sputtering method, the object to be deposited (support or protective layer) may be cooled or heated as necessary during sputtering. Further, the stimulable phosphor layer may be heat-treated after sputtering. A third method is the CVD method. This method involves decomposing a target photostimulable phosphor or an organometallic compound containing a photostimulable phosphor raw material with energy such as heat or high-frequency power, thereby producing a photostimulable material on a support that does not contain a binder. Obtain a fluorescent phosphor layer. tIS4 diagram (,) shows an example of the relationship between the stimulable phosphor layer of the radiation image conversion panel of the present invention obtained by the vapor deposition method and the amount of stimulable phosphor attached corresponding to the layer thickness and radiation sensitivity. represents. Since the stimulable phosphor layer produced by the vapor deposition method according to the present invention does not contain a binder, the adhesion resistance (filling rate) of the stimulable phosphor is lower than that of the conventional stimulable phosphor coated layer. The thickness of the stimulable phosphor layer is approximately twice that of the stimulable phosphor layer, and the radiation absorption rate per unit thickness of the stimulable phosphor layer is improved, resulting in not only high sensitivity to radiation but also improved image graininess. Furthermore, the stimulable phosphor layer produced by the vapor deposition method has excellent transparency and has high transmittance to stimulated excitation light and stimulated luminescence, making it easier to use the stimulable phosphor layer produced by the conventional coating method. An example of the sharpness of a panel of the present invention having a stimulable phosphor layer with a fine columnar block structure obtained as described above. The fourth
Shown in Figure (b). In the panel of the present invention, due to the light guiding effect of the fine columnar block structure, the stimulated excitation light is repeatedly reflected on the inner surface of the columnar block and is less likely to be dissipated outside the columnar block. As is clear from the comparison with b), it is possible to improve the sharpness of the image and to reduce the decrease in sharpness due to an increase in the layer thickness of the stimulable phosphor. The radiographic image conversion panel of the present invention provides excellent sharpness, granularity and sensitivity when used in the radiographic image conversion method shown schematically in FIG. That is, in FIG. 5, 51 is a radiation generator, 52 is a subject, 53 is a radiation image conversion panel of the present invention, 54 is a stimulated excitation light source, and 55
56 is a charging conversion device that detects stimulated luminescence emitted from the radiation image conversion panel; 56 is a device that reproduces the signal detected by 55 as an image; 57 is a device that displays the reproduced image; and 58 is a device that displays stimulated excitation. It is a filter that separates light and stimulated luminescence and allows only stimulated luminescence to pass through. In addition, 5 after 55
It may be any device that can reproduce the optical information from 3 as an image in some form, and is not limited to the above. As shown in FIG. 5, radiation from a radiation generating device 51 enters a radiation image conversion panel 53 of the present invention through a subject 52. This incident radiation is absorbed by the stimulable phosphor layer of the radiation image conversion panel 53, and its energy is accumulated to form a V product image of the radiation transmission image. Next, this accumulated image is excited with stimulated excitation light from the stimulated excitation light source 54 to emit stimulated luminescence. In the radiation #I image conversion panel 53 of the present invention, since the photostimulable phosphor layer has a fine columnar block structure, when scanning with the above-mentioned photostimulable excitation light, the photostimulable excitation light is absorbed into the photostimulable fluorescence. Diffusion through the body layers is suppressed. Since the intensity of the emitted stimulated luminescence is proportional to the amount of accumulated radiation energy, this optical signal is photoelectrically converted by a photoelectric conversion device 55 such as a photomultiplier tube, and an image reproduction device 56
The image of the subject is reproduced as an image and displayed on the image display device 57.

【Example】

The present invention will be explained with reference to the following example. Example 1 An aluminum plate having a thickness of 500 μm was anodized, sealed and heated by the method described above so that the tile-like plates were separated from each other by minute gaps. A support with a paved surface structure was placed in a vapor deposition apparatus.The average diameter of the tile-like plate was 60 microns.Next, an alkali halide stimulable phosphor ( 0.9RbB r ・0.ICsF
:O,0ITI) and set it on the resistance heating electrode.
Then, the evaporator was evacuated to 2 x 10-' T orr.
The degree of vacuum was set to . Next, an electric current is applied to the tungsten boat, and the alkali halide stimulable phosphor is evaporated by a resistance heating method, and the stimulable phosphor layer is deposited on the support until the layer thickness becomes 300 μm. A radiation image conversion panel A was obtained. The radiation image conversion panel A of the present invention thus obtained was irradiated with XM at a tube voltage of 80KV9 for 10 minutes, and then H
The e-Ne laser beam (633n) is used to stimulate excitation, and the stimulated luminescence emitted from the stimulable phosphor layer is charged and converted by a photodetector (photomultiplier tube), and this signal is transmitted by an image reproducing device. It was reproduced as an image and recorded on silver halide film. The sensitivity of the radiation image conversion panel A to X-rays was investigated based on the signal magnitude, and the modulation transfer function (MTF) and granularity of the image were investigated using the obtained images, which are shown in Table 1. In Table 1, the sensitivity to X-rays is shown as a relative value, with the radiation image conversion panel A of the present invention being taken as 100. Moreover, the modulation transfer function (M T F ) has a spatial frequency of 2
The values at cycle/-1 are shown, and the graininess (good, average, bad) is indicated by (○, Δ, X), respectively. Example 2 In Example 1, the layer thickness of the stimulable phosphor layer was changed to 150 μ-
A radiation image conversion panel B of the present invention was obtained in the same manner as in Example 1 except for the following. The thus obtained radiation llAm image conversion panel B of the present invention was evaluated in the same manner as in Example 1, and the results are also listed in Table 1. Example 3 In Example 1, the average diameter of the tile-like plate of the support was 12
A radiation image conversion panel C of the present invention was obtained in the same manner as in Example 1 except that the 0μ cage was used. The radiation image conversion panel C of the present invention thus obtained was evaluated in the same manner as in Example 1, and the results are also listed in Table tA1. Example 4 In Example 1, a 500μ thick aluminum plate was anodized in the same manner as in Example 1 as a support.
After sealing and heat treatment to create a surface structure in which tile-like plates are separated from each other by minute gaps, metal aluminum was vacuum-deposited to a thickness of 0.1 μm. A radiation image conversion panel D of the present invention was obtained in the same manner as in Example 1. By depositing metallic aluminum thinly in this manner, the tile-like surface of the aluminum support is blackened. The radiation image conversion panel D of the present invention was evaluated in the same manner as in Example 1, and the results are also listed in Table 1. Example 5 In Example 1, an aluminum plate with a spray thickness of 500μ was anodized in the same manner as in Example 1 as a support.
After sealing and heat treatment to create a surface structure in which tile-like plates are separated from each other by minute gaps, metal aluminum was vacuum-deposited to a thickness of 1 μm. A radiation image conversion panel E of the present invention was obtained in the same manner as in Example 1. By depositing metallic aluminum thickly in this way, the reflectance of the tile-like plate surface of the aluminum support was improved by about 20%. The radiation image conversion panel E of the present invention was evaluated in the same manner as in Example 1, and the results are also listed in Table 1. Comparative Example 1 Alkali halide stimulable phosphor (0,9RbBr・0,
8 parts by weight of ICsF:O,OIT l), 1 part by weight of polyvinyl butyral resin, and 5 parts by weight of a solvent (cyclohexanone) were mixed and dispersed to prepare a coating liquid for a stimulable phosphor layer. Next, this coating liquid was placed horizontally. It was coated uniformly on a black polyethylene naphthalate film as a support with a thickness of 300 μm and air-dried for 30 μm.
A stimulable phosphor layer with a theoretical thickness of 0 μm was formed. Comparative radiation image conversion panel P obtained in this way
was evaluated in the same manner as in Example 1, and the results are also listed in Table 1. Comparative Example 2 A comparative radiation image conversion panel Q was obtained in the same manner as in Comparative Example 1 except that the thickness of the stimulable phosphor layer was changed to 150 μ-. Comparative radiation image conversion panel Q obtained as in 2.
was evaluated in the same manner as in Example 1, and the results are also listed in Table 1. Table 1 As is clear from Table 1, the radiation image conversion panels A to E of the present invention each have a corresponding photostimulable phosphor layer thickness as the comparative radiation image conversion panel P. Compared to Q, the X-ray sensitivity was about twice as high and the image graininess was excellent. This is because the radiation image conversion panel of the present invention does not contain a binder in the stimulable phosphor layer and has a higher absorption rate of stimulable phosphor than a comparative panel when the filling rate of the stimulable phosphor is high <xm. It is. Furthermore, although the radiation image conversion panels A to E of the present invention have higher X-ray sensitivities than the comparative radiation image conversion panels P and Q each having a corresponding stimulable phosphor layer thickness, they have poor sharpness. But it was excellent. In the radiation image conversion panel of the present invention, cracks are created in the stimulable phosphor layer due to the gaps in the support, thereby creating a fine columnar block structure in which the stimulable phosphor layer is subdivided. This is because the scattering of the He--Ne laser, which is the stimulable excitation light in the stimulable phosphor layer, is suppressed and reduced.

【Effect of the invention】

As described above, according to the present invention, since the stimulable phosphor layer has a fine columnar block structure, the scattering of the stimulable excitation light in the stimulable phosphor layer is significantly reduced. It is possible to improve the sharpness of the image. In addition, according to the present invention, the decrease in image sharpness due to an increase in the thickness of the stimulable phosphor layer is small. It is possible to improve sensitivity. In addition, according to the present invention, the decrease in image sharpness due to an increase in the thickness of the stimulable phosphor layer is small. It is possible to improve the graininess of Further, according to the present invention, it is possible to stably manufacture the radiation image conversion panel of the present invention at low cost. The present invention has extremely great effects and is industrially useful.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a radiation image conversion panel of the present invention and a part of the support surface during the manufacturing process. FIG. 2 is a plan view showing an example of the distribution pattern of the micro tile-like plates. FIG. 3 is a diagram showing an example of a support. FIG. 4(a) is a diagram showing the thickness of the stimulable phosphor layer, the adhesion amount, and the sensitivity to radiation in a radiation image conversion panel according to an example of the present invention. , (b) is the modulation transfer function (M T F
). FIG. 5 is a schematic diagram of the radiation image conversion method used in the present invention. FIG. 6(a) is a diagram showing the photostimulable phosphor layer and adhesion amount in the conventional radiation image conversion panel, and the sensitivity to radiation; FIG. Modulation transfer function (M
It is a figure showing TF). 10... Panel 11... Distribution pattern layer 11ij... Micro tile-like plate (11ij)... Gap 12... Support 13... Stimulable phosphor layer 13ij... Fine columnar block (13ij)...Gap 14...Adhesive layer 15...Protective layer agent Patent attorney No 1) Parent-in-law Figure 1 ridge) O (b Figure 2 Figure 4 (α) o zoo 4' o Kuzugarami-) 5th plan 4 6th I! l (α) Procedural amendment March 14, 1986

Claims (1)

[Claims] 1) In a radiation image conversion panel having a stimulable phosphor layer on a support, a support having a surface structure in which a large number of micro tile-like plates are laid out and separated from each other by minute gaps. 1. A radiation image conversion panel comprising: a stimulable phosphor layer having a fine columnar block structure that directly inherits the surface structure on the support; 2) The radiation image conversion panel according to claim 1, wherein the micro tile-like plate is an anodized layer of aluminum. 3) In a method for producing a radiation image conversion panel having a stimulable phosphor layer on a support, the support has a surface structure in which a large number of micro tile-like plates are laid out and separated from each other by minute gaps. A method for manufacturing a radiation image conversion panel, comprising the steps of: forming a stimulable phosphor layer having a fine columnar block structure on the surface of the support, inheriting the surface structure as it is. 4) The support is made of aluminum, and the support includes a step of forming an anodized layer on the surface of the aluminum support by an anodizing method, a step of sealing the anodic oxide layer, and then a heat treatment of the support. a stimulable phosphor with a fine columnar block structure inheriting the surface structure of the anodic oxide layer as it is on the micro tile-like plate formed by the gap; 4. The method of manufacturing a radiation image conversion panel according to claim 3, further comprising the step of forming a layer.