JPS62110200A - Manufacture of radiation picture conversion panel - 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 method of manufacturing a radiation image conversion panel using a stimulable phosphor, and more particularly to a method of manufacturing a radiation image conversion panel that produces five highly sharp radiation images.

[Prior art]

V Alll1Tti llh sa l-Q
? , -+h O, + j, el 1iri
llh I half '4''-(To embryo old door,
・It is often used for y. In order to obtain these two images, X-rays that have passed through the subject are irradiated onto a phosphor layer (phosphor screen), thereby producing visible light, and this visible light is then irradiated with silver salt in the same way as when taking ordinary photographs. A so-called radiographic photograph is used, which is a film made by irradiating and developing the film. 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 by the absorption as fluorescence. There is a method of detecting this fluorescence and creating an image. Specifically, for example, U.S. Pat.
No. 5-12144 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 with a stimulable phosphor layer formed on a support.The stimulable phosphor layer of this radiation image conversion panel is exposed to radiation that has passed through the object, and each part of the object is visualized. What is the radiation energy corresponding to the radiation transparency? This photostimulable phosphor layer is then scanned with photostimulable excitation light to emit the accumulated radiation energy in each part as stimulated luminescence, which produces an optical signal based on the intensity of this light. For example, the battery is charged and converted, and an image is obtained by an image reproducing device. This final image may be reproduced as a hard copy or on a CRT. Now, the radiation image conversion panel having a stimulable phosphor layer used in this radiation image conversion method has a radiation absorption rate and a light conversion rate (including both In addition to having high radiation sensitivity (hereinafter referred to as "radiation sensitivity"), images are required to have 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 30 μm and an organic binder on a support or a protective layer. It is created using a manufacturing method that involves coating and drying.
The packing density of the stimulable phosphor is low (filling rate 50%), and in order to obtain sufficiently high radiation sensitivity, the /l! ! It needed to be thicker. As is clear from the figure, the layer thickness of the stimulable phosphor layer is 200 μm.
When I, the adhesion resistance amount of stimulable phosphor is 50u+g/c++
+2, and the radiation sensitivity increases linearly up to a layer thickness of 350 μm and is saturated above 450 μm. Note that the radiation sensitivity becomes saturated because when the stimulable phosphor layer becomes too thick, the stimulated luminescence generated inside the stimulable phosphor layer is emitted to the outside due to scattering between the stimulable phosphor particles. This is because it will not come out. On the other hand, as shown in FIG. 4(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 the performance, it was necessary to make the stimulable phosphor layer thinner. In addition, the graininess of images in the radiation image conversion method is determined by local fluctuations in the number of radiation quanta (quantum mottles) or structural disturbances in the stimulable phosphor layer of the radiation image conversion panel (structural mottles). When the layer thickness of the stimulable phosphor layer becomes thinner, the number of single rays absorbed by the stimulable phosphor layer decreases, resulting in an increase in quantum mottles, and structural disorder becomes apparent, resulting in an increase in structural mottles. This may cause a decrease in image quality. Therefore, in order to improve the graininess of images, the stimulable phosphor layer needs to be thick. That is, as mentioned above, in the conventional radiation image conversion panel, the sensitivity to radiation, the graininess of the image, and the sharpness of the image exhibit completely opposite trends with respect to the layer thickness of the stimulable phosphor layer. Radiographic image conversion panels have been developed by mutually sacrificing radiation sensitivity, graininess, and sharpness to some extent. 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. In the radiation image conversion method using a stimulable phosphor, it is not determined by the spread of the stimulated luminescence of the stimulable phosphor, but rather by the spread of the stimulable luminescence of the phosphor as in radiography. It depends on the spread of the stimulated excitation light within the panel. This is because in this radiation #X image conversion method, the radiation image information that has not been accumulated in the radiation image conversion panel is retrieved in a time-series manner.
Preferably, all of the stimulated luminescence due to the all exhaustion excitation light irradiated at time i) is collected and recorded as an output from a certain pixel (x++yi) on the panel that was irradiated with the stimulation excitation light at that time. If the stimulated excitation light is scattered within the panel,
If the stimulable phosphor spreads by L etc. and excites the stimulable phosphor existing outside the irradiated pixel (xi+yi), the above (xi
, yi), the force from a wider area than that pixel is recorded as the output from the pixel. Therefore,
IIr due to stimulated excitation light irradiated at a certain time (ti)
Even if the I-stimulated luminescence is only from the pixels (xi, yi) on the panel that were truly irradiated with the stimulated excitation light at that time (ti), it will not affect 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 image conversion panel described in No. 500 is colored so that the average reflectance of the stimulable phosphor in the stimulated excitation wave a region is smaller than the average reflectance of the stimulable phosphor in the stimulated emission wavelength region. Method etc. However, in these methods, improving sharpness inevitably leads to a significant decrease in sensitivity, and therefore cannot be said to be a preferable method. On the other hand, the present applicant has already applied for patent application No. 59-19636.
No. 5 describes a new radiation image conversion panel that improves the conventional drawbacks of radiation image conversion panels using stimulable phosphors as described above, and a method for producing the same, in which the stimulable phosphor layer contains a binder. We are proposing a radiation image conversion panel that does not require the use of radiographic images, and a method for manufacturing the same. 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. Furthermore, the present applicant has filed Japanese Patent Application No. 59-266912-2669.
In issue 16, I[liri'! This paper proposes a radiation image conversion panel in which the phosphor layer has a fine columnar block structure and a method for manufacturing the same. According to this, Hikaru 7? - Due to the light guiding effect of the fine columnar block structure, the excitation light reaches the bottom of the columnar block without being dissipated outside the columnar block while repeating reflection within the columnar block, further increasing the sharpness of images due to stimulated luminescence. can do. However, the said patent application No. 59-2613912-266
In the radiation image conversion panel manufacturing method of No. 916,
A fine uneven pattern on the surface of the support, which is the base layer of the fine columnar block, or a t'ft structure in which fine tile-like plates are separated from each other and laid out, or minute tile-like plates and a fine wire network that partitions them. It has the disadvantage that the manufacturing process is complicated because it includes the process of manufacturing a combination of. Furthermore, it is difficult to make the structure of the base layer finer than a certain level, and there is also a limit to the sharpness of images.

[Object of the Invention] The present invention provides a 1ft. An object of the present invention is to provide a method for manufacturing a radiation image conversion panel that improves sensitivity to radiation and provides images with high sharpness. Another object of the present invention is to provide a method for manufacturing a radiation image conversion panel that has improved graininess and provides images with high sharpness. Still another object of the present invention is to provide a simple manufacturing method that can stably manufacture a radiation image conversion panel (hereinafter referred to as a conversion panel) at low cost. Structure of the Invention The object of the present invention is to provide a method for producing a radiation image conversion panel having at least one photostimulable phosphor layer on a support, in which the stimulable phosphor layer is placed in a gas atmosphere. A step of vapor depositing to form a phosphor layer having voids, and a step of heating the stimulable phosphor layer to expand a portion of the voids in the thickness direction of the stimulable phosphor layer. This is achieved by a conversion panel manufacturing method characterized by the following. Next, the present invention will be specifically explained. 2 is a schematic diagram of an example of a vapor deposition apparatus 1" used for forming a stimulable phosphor layer in a vacuum chamber 20, a vacuum chamber substrate 21, and a part thereof. Exhaust port 22 and May valve 2
It has 3. Inside the vacuum chamber 20 is a boat or crucible 24 for heating the evaporation source, and the boat or crucible is filled with a stimulable phosphor 25. Support 2 of the conversion panel is placed above the open end of the boat or crucible 24.
There are 6! The III-stimulable fluorescent phosphor is deposited on the surface of this support to form a stimulable phosphor layer. A heater 27 for heating the support is provided above the support 26, and a measuring element 28 for controlling the film thickness is arranged in parallel with the support. A vacuum gauge 211 is attached to a tube 29 for introducing an inert gas through the vacuum chamber substrate 21, and a barrier pull leak pulp 210 that can control the inflow of a minute amount of gas is attached to the gas introduction tube 29. The vapor deposition apparatus used in the panel manufacturing method of the present invention is not limited to the one shown in FIG. 2, but can be any apparatus that can vapor deposit the stimulable phosphor onto the object to be vapor-deposited in an inert gas atmosphere. It can be anything. Now, the panel manufacturing method of the present invention using the apparatus shown in FIG. 12 will be described as a specific example. In this method, the support is first placed in a vapor deposition apparatus, the inside of the apparatus is evacuated, and 10-
The degree of vacuum is approximately 6 to 10-' Torr. Then, the heating temperature of 300 to 500
After cleaning the surface of the support by heating it to °C, set the temperature of the support to about 100-200'C, open the barrier pull leak pulp 210, and introduce an inert gas such as Ar%He5Nz. and the pressure is 10-10-' Torr
The vacuum should be as low as possible. A preferable atmospheric gas is A
It is r. Next, the port or crucible 24 is energized to evaporate the stimulable phosphor 25 in the boat or crucible, such as a rubidium bromide phosphor using thallium as an activator, by a resistance heating method. Then, the stimulable phosphor is deposited on the support 26 and at the same time crystals grow, forming columnar crystals in a direction perpendicular to the surface of the support. However, during the vapor deposition process, there are crystal planes where crystal growth is promoted, and there are planes where atmospheric gas is partially adsorbed and crystal r&suppression is suppressed. The surface where crystal growth is promoted grows steadily in the direction to which the evaporated molecules or atoms attach. 'The surface where crystal growth is suppressed forms many fine cavities or voids within the deposited layer. The shape of the cavity is often an elongated shape extending substantially perpendicularly to the surface of the support. In this way, a stimulable phosphor layer having a large number of fine cavities is formed on the support by vapor deposition. At this time, the growth rate of the stimulable phosphor layer deposited while adsorbing the atmosphere is 102 to 10'A/min, preferably 103 to 106 A/rIlin. When the panel having the stimulable phosphor layer prepared in this way is taken out into the atmosphere and heat-treated at a temperature of about 300 to 400'C, some of the cavities in the stimulable phosphor layer are removed. It extends in a direction perpendicular to the surface of the support and develops along the interface between the columnar crystals, forming voids or cracks (although some remain as cavities). In this way, the columnar crystals are formed into optically independent columnar blocks each having a shape in which several pieces are bundled and separated by the voids or cracks. A fluorescent phosphor layer is formed. The above example describes the case where heat treatment is performed in the atmosphere, but even if this is omitted and baking in the exhaust air is applied to the process of purchasing and forming columnar broncs, the heater is heated to a high temperature, that is, 300°C to 400°C. The heat treatment may be set to a certain degree to encourage the formation of a columnar block structure similar to that in the heat treatment described above at the same time as vapor deposition. In addition, in the direct deposition process, instead of the resistance heating method,

[l Electron beam method may be used. Furthermore, in the vapor deposition process, it is possible to carry out co-evaporation using multiple resistance heaters or electron beams, and it is also possible to co-evaporate the stimulable phosphor raw material using multiple resistance heaters or electron beams. It is also possible to form the stimulable phosphor layer at the same time as vapor deposition and synthesis of the desired stimulable phosphor on the support. After the completion of the vapor deposition step and the heat treatment step, a conversion panel is manufactured by forming a protective layer, preferably on the surface of the stimulable fluorescent water layer on the support, which is exposed to the outside air. . Note that the step of providing a support after forming the stimulable phosphor layer on the protective layer may be taken.6 Figure 1 shows a cross section in the thickness direction of an example of a conversion panel manufactured by the panel manufacturing method of the present invention. Shown as a diagram. In the figure, numeral 10 indicates the form of a conversion panel related to the present invention. 11 is a support, 12 is a stimulable phosphor layer extending substantially perpendicular to the surface of the support and having an r-fine columnar block structure, 12a represents each fine columnar block, 12
b represents a minute void or crack that separates 12a. Further, in the fine columnar block, there is an elongated cavity 12c extending substantially perpendicularly to the surface of the support. The average diameter of the fine columnar blocks 12a is 1 to 400μ
m is preferable, and the void 12 between the fine columnar blocks is preferably
b may be any distance as long as the fine columnar blocks 12a are optically independent from each other, but on average it is 0 to 2.
0 μm is preferable. The spacing between the cavities 12c is preferably 100 μm or less, more preferably 40 μm or less. Note that a protective layer 13 is provided on the stimulable phosphor layer 12.
It is preferable to provide Further, an adhesive layer may be provided between the support 11 and the stimulable phosphor layer 12 to improve the adhesion between each layer, as required, or an adhesive layer may be provided between the support 11 and the stimulable phosphor layer 12. Alternatively, a reflective layer or an absorbing layer for photostimulated luminescence may be provided.In the panel application method of the present invention, the photostimulable phosphor is a material that is , refers to a phosphor that exhibits stimulated luminescence corresponding to the initial light or high-energy radiation irradiation amount due to thermal, mechanical, chemical, or electrical stimulation (photostimulation excitation), but it is not practical. It is a phosphor that emits IIIE light with a stimulable excitation light of preferably 500 nm or more from the surface. Examples of the stimulable phosphor used in the safety panel of the present invention include, for example, Japanese Patent Application Laid-Open No. 48-8048.
B aS O4:A x (However, A
is at least one of Dy, Tb and Tm, and X
is 0.001≦x<1 mol%. ), M gS O4 described in JP-A-48-80488:
A phosphor represented by A
O, :A x (where A is at least one of Dy, Tb and Tm, and X is 0.001≦×1 mol%), JP-A-51-29889
Phosphors in which at least one of Mn, Dy, and Ti) is added to Na2SO, CaSO, Ba5O-, etc., described in Japanese Patent Application Laid-Open No. 1983-30487; , LiF. Phosphors such as MgSO4 and CaF2, JP-A-53-39
L i 2 B 407 described in No. 277:
Phosphors such as Cu HA g, JP-A-54-47883
Lizo・(B 202)X:C described in the issue
u (where x is 2<x≦3), and L i 20・(B
202) X: Phosphors such as Cul A g (where X is 2≦3), SrS: Ce, Sm, SrS; Eu, Sm described in U.S. Pat. No. 3,859,527
, La2O2S:Eu, Sm and (Z n = C
d) S: Mn, X (However, X is halogen)
Examples include phosphors represented by Also, JP-A-55-
ZnS:Cu, Pb phosphor described in No. 12142, barium aluminate phosphor whose general formula is represented by Bao-xA 1□03:E u (however, 0.8≦X≦10), and general formula Force M” 0-xS io 2:A
(However, 1. M” is at least 1 of MgvCatPb, TI, Bi, and Mn! r at t1), × is 0.5≦
X≦2.5. ) Alkaline earth metal silicate-based phosphors represented by: Also, the general formula is (Bat-x, MgxCa, )FX: eEu
” (However, X is at least one of Br and CI, x, y, and e are O<x+y≦0.6, xy≠
This is a number that satisfies the following conditions: O and 10+6≦e≦5×10+2. ) can be mentioned. General formula % formula %: (Ln is at least one of La, Y, Gd and Lu, X is C1 and/or Br, A is Ce and/or T
b, and X represents a number satisfying O<x<0.1. The general formula of the phosphor represented by JP-A-55-12145 is (B a I
” is Mir+CavS r+at least one of Zn and Cd, X is CI, Br and VI),
11 ()-L 1 4, A
I+ V n, T h, (', a-T +n, n
At least one of u-PrtHo, NdtYb and Er, x and y are O≦X≦0.6 and 0≦y≦
It represents a number that satisfies the condition of 0.2. ), the general formula described in JP-A-55-84389 is B aF X :xCe,yA (where X is CI, B
At least one of r and ■, A is In, TI, G
is at least one of d, Sw, and Zr, and X and (/V are 0 x ≦ 2
It is X10-2. ), a phosphor expressed by JP-A-1987-
The general formula described in No. 160078 is MlFX-xA:yLn (where Ml is M gs Cat Bat S rf
At least one of Z n and (/Cd, A 1.t
B e Ot M g Ot Ca OvS ro
=B ao , Z no −A I20−Y 20 C
1-L n20:ltI n203. S io 2.
Tio 2. ZrOt, Geo,, S no 2゜N bzo s, T n20 s and The2 (both are one type, Ln is EutTbtCetTm, Dy
tPrtHotNd. At least one of Yb, Er, Sm, and Gd, X is at least one of CI, Br, and I, and X and y are 5X10-'≦X≦0.5 and o<y, respectively. This is a number that satisfies the condition of ≦0.2. ) Rare earth element-activated divalent metal fluorohalide phosphors, whose general formulas are ZnS:A, (Zn, Cd)S:A, CdS:A
, ZnS: A, X and ucds: A, X ((BLA is Cu
. Ag*Au or Mn, and X is halogen. ), general formula [1] or [Il) described in JP-A-57-148285, general formula (1) xMi(pot)2-NX2:yA
General formula (n) M, (PO,)2・yA (wherein M and IN are respectively M Fi + Cal S r,
At least one of B atZn and Cd, X is F
, C.I. At least one of Br and I, A is E u, T
b. CelTm*Dy*Pr*HomN'd*Er+sb+
T' lt represents at least 1a among Mn and Sn. Further, X and y are numbers that satisfy the condition 0<x≦6.0≦y≦1. ), a phosphor represented by general formula (III)
or (IV) general formula (III) nReX3·mA
X': xEu general formula (■) nReXz・mAX;
:xEu, ysm (where Re is La, GdtY, Lu
at least 1!11, A is an alkali ±yII metal, Ba, at least one of Sr*Ca, X and X'
represents at least one of F, CI, and Br,
Moreover, X and y are 1xio-'<x<3 Xl0-
', I Xl0-'< y < I Xl0-1, and n7m is I X 10-'
The condition <n7m<7×10-' is satisfied. )
A phosphor represented by the general formula % formula %: (However, Ml is at least one kind of alkali metal selected from Li, Na, Rb and 1/Cs, and Ml is Be + M g + Ca + S r r B
at Z n t Cd v At least one divalent metal selected from Cu and Ni. Ml is SctY
tLatCetPrtNdtPm, 51EutGdtT
btDy+Ho+Er+T+a+Yb, Lu+A It
It is at least one trivalent metal selected from Gat and In. x, x' and x'' are at least one kind of halogen selected from F, CI, Br and engineering. A is Eu. T byce+T III, Dy+P r, Ho+N
d+Y b+E rtG dtL usStatY+
It is at least one metal selected from TLNa+Ag+Cu and Mg. Also, a is a numerical value in the range of 0≦a<0.5, and b is a value in the range of O≦b
C is a numerical value in the range of <o, s, and C is a numerical value in the range of O<c≦0.2. ) and the like can be mentioned. In particular, alkali halide phosphors are suitable and preferred phosphors for vapor deposition. However, the IQI exhaustible phosphor used in the panel manufacturing method of the present invention is not limited to the above-mentioned phosphor, but is a phosphor that exhibits stimulated fluorescence when irradiated with radiation and then irradiated with stimulated excitation light. Any phosphor that is phosphor may be used. The panel manufacturing method of the present invention may include a step of forming 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 panel manufacturing method of the present invention, various polymeric materials, glass, metals, etc. are used as the support. In particular, materials that can be processed into flexible sheets or webs are suitable for handling as information recording materials, such as cellulose-containing acetate films and polyester films. Polyethylene terephthalate film, poly7mid film, polyimide film, triacetate film,
Plastic films such as polycarbonate films,
A metal sheet of aluminum, iron, @, chromium, etc., or a metal sheet having a coating layer of the metal oxide is preferred. The layer thickness of these supports varies depending on the material of the support used, but is generally 80 μm to 100 μm, more preferably 80 μm to 5 μm from the viewpoint of handling.
00 μm. In the panel manufacturing method of the present invention, generally a protective layer for physically or chemically protecting the stimulable phosphor layer group may be provided on the surface where the stimulable phosphor layer is exposed. preferable. This first protective layer may be formed by directly coating the protective layer coating liquid on the stimulable phosphor layer, or by adhering a separately formed protective layer on the stimulable phosphor layer. Good too. The material for the 31st layer is cellulose acetate,
Nidomicellulose, polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene terephthalate, polyethylene, polypropylene, polyvinylidene chloride, nylon, polytetrafluoroethylene, polytetrafluoroethylene, polytetrafluoroethylene, polytetrafluoroethylene Materials for the protective layer such as ethylene-propylene hexafluoride copolymer, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride, and acrylonitrile copolymer are used. In addition, this insulation layer is formed by vacuum evaporation, sputtering, etc.
S iC, S io 2. It may also be formed by stacking inorganic materials such as SiN and AI203. Since the conversion panel obtained by the panel manufacturing method of the present invention as described above does not contain a binder in the photostimulable phosphor layer, the adhesion resistance amount (filling rate) of the photostimulable phosphor is lower than that of the conventional photostimulable material. The amount of phosphor is approximately twice that of the stimulable phosphor layer coated with phosphor, and the radiation absorption rate per unit thickness of the stimulable phosphor layer is improved, resulting in high sensitivity to radiation, and image graininess. will improve. Furthermore, the stimulable phosphor layer formed by the vapor deposition method has excellent transparency, and has high transmittance to stimulated excitation light and V-stimulated emission, making it possible to increase the layer thickness of the stimulable phosphor layer formed by the conventional coating method. It is possible to do this, making it even more sensitive to radiation. FIG. 3(a) shows an example of the relationship between the photostimulable phosphor deposition amount and the radiation sensitivity corresponding to the stimulable phosphor layer and the layer thickness of the conversion panel produced by the panel manufacturing method of the present invention. Further, an example of the sharpness of a panel having a stimulable phosphor layer having a fine columnar block structure obtained by the panel manufacturing method of the present invention is shown by a characteristic curve 31 in FIG. 3(b). According to the panel manufacturing method of the present invention, Japanese Patent Application No. 59-266
A finer structure than the fine columnar block structure described in No. 912-266916 is formed, and the resulting panel has a light induction effect in which the stimulated excitation light goes up the inner surface of the columnar block and is repeatedly reflected inside at the cavity surface. For example, as is clear when compared with the tile-shaped 32 shown in Japanese Patent Application No. 59-266914, the sharpness of the image is improved and the sharpness is further improved as the layer thickness of the stimulable phosphor increases. is possible. In addition, the characteristics of the conversion panel manufactured by the conventional manufacturing method in which stimulable phosphor particles are dispersed and coated in a binder are shown at 33 in Figure 3(b).
Shown below. This clearly shows that the image sharpness is excellent. Further, the panel manufacturing method of the present invention is disclosed in Japanese Patent Application No. 59-266
No. 912-266915
Conventional panels do not require manufacturing processes such as a base layer with a columnar block structure, that is, a fine uneven pattern on the surface of the support, a micro tile-like plate structure, or a combination of a micro tile-like plate and a fine wire mesh. The manufacturing method is considerably simplified. [Examples] Next, the present invention will be explained by examples. Example 1 A 0.5I thick aluminum plate was placed in the vapor deposited layer as a support. Next, molybdenum for resistance heating: 0.004
Tu was placed in the evaporator, and the resistive heating electrode was evacuated to a vacuum of 10-' Torr. Next, the support was heated to 300℃ using a heater for heating the support.
After cleaning the surface of the support by heating it to ~500'C, the support was set at 100'C, and argon gas was introduced to maintain it at about I x 10-'Torr. Next, the molybdenum boat was energized and RbBr: 0.
004TQ was evaporated to create a conversion panel material having a stimulable phosphor layer with a thickness of about 250 μm. This conversion panel material was taken out into the atmosphere and heat treated at 350° C. for 30 minutes to form a conversion panel material of the present invention. Converted panel A using the panel manufacturing method of
I got it. After irradiating 10 IIR of X-rays with a tube voltage of 80 KVp to the conversion panel A obtained by the panel manufacturing method of the present invention thus obtained, the conversion panel A is stimulated with semiconductor laser light (780 nw) and radiated from the photostimulable phosphor layer. The photodetector (
This signal was reproduced as an image by an image reproducing device and recorded on a silver halide film. The sensitivity of the conversion panel AI:r) to X-rays was investigated from the signal magnitude, and the modulation transfer function (M T F ) and graininess of the image were investigated from the obtained images, which are shown in Table 1. In the #IJ1° table, the sensitivity to X#i is expressed as a relative value of 100 for panel A of the present invention. Further, the modulation transfer function (MTF) is a value when the spatial frequency is 2 cycles/mm. Example 2゜In Example 1, the argon pressure during vapor deposition was changed to 5×10-'
Conversion by the panel manufacturing method of the present invention was carried out by carrying out the same operations as in Example 1 except for setting the support temperature during vapor deposition at 350°C and omitting the heat treatment after the completion of vapor deposition. Panel B was obtained. The thus obtained conversion panel B manufactured by the panel manufacturing method 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 8 parts by weight of photostimulable phosphor RbBr: 0.004T rl, 1 part by weight of polyvinyl butyral resin, and 5 parts by weight of a solvent (cyclohexanone) were mixed and dispersed, and applied for a stimulable phosphor layer. The liquid was adjusted. Next, this coating solution was uniformly applied onto a horizontally placed black polyethylene terephthalate film having a thickness of 300 μm as a support and air-dried to form a stimulable phosphor layer having a thickness of 250 μm. The comparative conversion panel P obtained in this way is Example 1
It was evaluated in the same manner as above, and the results are also listed in Table 1. Comparative Example 2 An aluminum plate with a thickness of 0.5+am was obtained in a patent application filed in 1986-266.
A support with a surface t'iVj structure in which tile-like plates are separated from each other by minute gaps by anodizing treatment, sealing treatment, and heat treatment by the method shown in No. 914 is installed during vapor deposition. did. Next, an alkali halide stimulable phosphor RbBr:0.004TQ was placed in a molybdenum boat for resistance heating, and set on an electrode for resistance heating.Then, the inside of the evaporator was evacuated and I The degree of vacuum was set to Torr. Next, the support is heated to a temperature of 300 to 500 by using a heater for heating the support.
・/+lI YuhnInl Cape - Responsibility 1 - Kunomi ↓ Demand 5 prayers) 9 (Ke 1h return; East is 1 zu! Set the temperature to 100℃, vacuum degree of 2 X 10-' Torr Next, the molybdenum boat was energized and Rb was heated using the resistance heating method.
B r:o,004T Q was evaporated and vacuum deposited to a thickness of about 250 μι to obtain a comparative conversion panel Q. The comparative conversion panel Q obtained in this way is Example 1
It was evaluated in the same manner as above, and the results are also listed in Table 1. As is clear from Table 1, the conversion panels A and B manufactured by the manufacturing method of the present invention had Xm sensitivity approximately twice as high as that of the comparative conversion panel P, and had excellent image graininess. This is because the conversion panel manufactured by the manufacturing method of the present invention does not contain a binder in the stimulable phosphor layer, and the charging rate of the stimulable phosphor is higher than that of the stimulable phosphor layer. This is because the line absorption rate is good. In addition, the conversion panels A and B produced by the manufacturing method of the present invention were superior in sharpness to the comparative conversion panel P despite having higher xi sensitivity. According to the manufacturing method of the present invention, the stimulable phosphor layer of the conversion panel has a fine columnar block structure and fine voids, so the stimulable phosphor layer of the conversion panel has a fine columnar block structure and fine voids. This is because the number of pores in the body layer is reduced. Furthermore, a conversion panel A produced by the manufacturing method of the present invention. Compared to the comparative conversion panel Q, B had superior sharpness even though the XM sensitivity and graininess were the same. This is because in the manufacturing method of the present invention, vapor deposition is performed in an argon atmosphere and heat treatment is performed, so conversion panels A and B have a finer structure than the fine columnar PRO-2 structure of comparison conversion panel Q. This is because it has a better light-inducing effect.

【Effect of the invention】

As described above, according to the present invention, since the stimulable phosphor layer has a fine columnar block structure and fine voids, scattering of stimulable excitation light in the stimulable phosphor layer is significantly reduced. As a result, the sharpness of the image can be improved. Furthermore, according to the present invention, the decrease in image sharpness due to an increase in the stimulable phosphor layer is small, so by increasing the stimulable phosphor layer, radiation sensitivity can be increased without reducing image sharpness. It is possible to improve. In addition, according to the present invention, since the decrease in image sharpness due to an increase in the stimulable phosphor layer is small, by increasing the stimulable phosphor layer thickness, the image sharpness can be improved without decreasing the image sharpness. It is possible to improve graininess. 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 part of an example of a conversion panel manufactured by the manufacturing method of the present invention. FIG. 2 is a schematic diagram showing an example of a vapor deposition apparatus used in the present invention. FIG. 3(a) is a diagram showing the thickness and adhesion amount of the stimulable phosphor layer and the sensitivity to radiation in an example of the conversion panel made according to the present invention, and FIG. 3(b) is a diagram showing the spatial frequency and the modulation transfer function ( MT
FIG. FIG. 4(a) is a diagram showing the stimulable phosphor layer, its adhesion amount, and sensitivity to radiation in the conventional conversion panel, and FIG. 4(b) is a diagram showing the thickness and radiation sensitivity of the stimulable phosphor layer in the conventional conversion panel. Modulation transfer function when the adhesion amount and spatial frequency are 2 cycles/Ifim (
FIG. 10... Conversion panel 11... Support body 12.
... Stimulable phosphor layer 13 ... Protective layer 20 ... Vacuum chamber 21 ... Vacuum chamber substrate 22 ... Exhaust port 23 ... Main valve 24 ... Boat or crucible 25 ... Stimulable phosphor 26...Support 27.
・・Heater for heating the support 28 ・・M 11 and 29 ・・〃S inlet pipe 210 ・・Barrier pull leak valve 211 ・・Vacuum gauge 31 ・・・Characteristic curve 32 of the conversion panel according to the manufacturing method...Characteristic curve 33 of the conversion panel having a fine columnar block structure...Characteristic curve of the conventional conversion panel Applicant: Roku Konishi Photo Industry Co., Ltd. Figure 1 10: Changeable sharpness, 0 ne 1 shi 11: Tenpōtai 12: Propaganda's teachings) 1 12a: Tachi6ta Nero r-l Meko block 12b: Kengari, 12c: '? Second eye 13; Sakugo row Figure 2 2゜・Vacuum tank 22: Size P mouth 24: 1 し・) Ya (25: Semi fusion 9 shares 26 2 in) nζ. Figure 3 (b) Interrogation Shusuke (1ri □□) Figure 4

Claims (1)

[Claims] In a method for producing a radiation image conversion panel having at least one stimulable phosphor layer on a support, the stimulable phosphor layer is deposited in an inert gas atmosphere to form a phosphor layer having voids. A method for manufacturing a radiation image conversion panel, comprising the steps of heating the stimulable phosphor layer and expanding a portion of the voids in the thickness direction of the stimulable phosphor layer.