JPS6239799A - Radiation image 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 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-ray images are often used for disease diagnosis. In order to obtain this X-ray image, the X#I that has passed through the object is irradiated onto the phosphor N (fluorescent screen), thereby producing visible light and displaying this tilted image.
1-10
17 Developed by irradiating the film using Shio,
A so-called radiograph is used. 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. Regarding weapons, for example, US Pat. No. 3,859,527 and Japanese Patent Application Laid-open No. 5
5-12] No. 44 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 1III stimulable phosphor 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. Radiation energy corresponding to the transmittance is accumulated to form a latent image, and then this stimulable phosphor layer is scanned with stimulable light to radiate the accumulated radiation energy of 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 may be reproduced as an image 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 uses particulate X1 with a particle size of about 1 to 3077111.
Since it is prepared by coating and drying a dispersion containing a stimulable phosphor and an organic binder on a support or a protective layer, the stimulable phosphor has a low light intensity (filling rate of 50%). ), in order to sufficiently increase the radiation sensitivity, it was necessary to increase the thickness of the stimulable phosphor layer, as shown in FIG. 5(a). As is clear from the figure, the layer thickness of the III exhaustible phosphor waste is 20 mm.
At 0μIff, the amount of stimulable phosphor attached is 50 +n
g/c If12, and the radiation sensitivity increases linearly up to a layer thickness of 350 μm and is saturated above 450 μm. The radiation sensitivity is saturated because if the stimulable phosphor layer becomes too thick, the XI'11 stimulable phosphor interparticle phosphor layer scatters inside the stimulable phosphor layer. This is because the stimulated luminescence of the light does not come out to the outside. On the other hand, as shown in FIG. 5 (IJ), the image sharpness in the radiation image conversion method tends to be higher as the thickness of the radiation image conversion panel 111E and the fluorescent phosphor layer is thinner. In order to improve sharpness, it was necessary to make the bright phosphor layer thinner. Furthermore, the graininess of the image in the radiation image conversion method is determined by local fluctuations in the number of radiation Mffi molecules (quantum mottles) or structural disturbances in the stimulable phosphor layer of the radiation image conversion panel (structural mottles). Therefore, when the layer thickness of the stimulable phosphor layer becomes thinner, the number of radiation quanta collected in the stimulable phosphor layer decreases and the quantum mottle increases. This may cause an increase in image quality, resulting in 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. The radiation image conversion panels have been made with some sacrifice in radiation sensitivity, graininess, and sharpness. 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. The sharpness of images in radiation image conversion methods using stimulable phosphors is not determined by the spread of stimulated luminescence of the stimulable phosphors in the radiation image conversion panel; It is not determined by the spread of the phosphor's emission, but rather depends on the spread of the stimulated excitation light within the panel. This is because in this radiation image conversion method, the radiation image information stored in the radiation image conversion panel is retrieved in a time-series manner. - Stimulated luminescence caused by excitation light is preferably recorded as an output from a certain pixel (xi + yi) on the panel that was illuminated with the stimulated excitation light at that time, but if the stimulated excitation light If it spreads within the panel due to scattering etc. and excites the stimulable phosphor that exists outside the irradiated pixel (xi + yi), the output from the pixel (xi, yi) will be an area wider than that pixel. The output from the ginger is recorded. Therefore, the stimulated luminescence due to the stimulated excitation light irradiated at a certain time (ti) is transmitted from the pixel (i, yi) on the panel that was truly irradiated with the stimulated excitation light at that time (ti). If only the emission of
No matter how wide the emission is, it does 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-55-14
Method of mixing white powder into the stimulable phosphor layer of a radiation image conversion panel described in No. 6447, JP-A No. 55-1635
The radiation M image conversion panel described in No. 00 is colored so that the average reflectance in the stimulated excitation wavelength region of the stimulable phosphor is smaller than the average reflectance in the stimulated emission wavelength region of the stimulable phosphor. method etc. However, in these methods, improving the sharpness inevitably leads to a significant decrease in sensitivity, and therefore cannot be said to be a preferable method. On the other hand, in light of this, 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 the radiation image conversion panel that uses ITI exhaustible phosphor as mentioned above. We are proposing a 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. , the radiation sensitivity and image graininess of the radiation image conversion panel are improved, and at the same time, image sharpness is also improved. However, in the radiation image conversion method, the sensitivity,
The requirements for image quality with high sharpness without compromising graininess are becoming ever more stringent.

OBJECTIVE OF THE INVENTION 1 The present invention relates to a radiation image conversion panel using R1 exhaustible phosphor proposed for mud prevention, and is intended to further improve the same. The object of the present invention is to provide a radiation image conversion panel that provides highly accurate images. Another object of the present invention is to provide a radiation image conversion panel that has improved graininess and provides images with high sharpness. [Structure of the Invention] The object of the present invention described above is -1! , is achieved by a radiation image conversion panel having a porous chromium layer on a support and having at least one stimulable phosphor layer to the north of the porous chromium layer. Next, the present invention will be specifically explained. FIG. 1(a) is a sectional view in the thickness direction of a radiation image conversion panel (hereinafter sometimes simply referred to as "panel" when the meaning is clear) of the present invention. In the figure, numeral 10 indicates the form of the panel of the present invention. 11 is a support made of aluminum, and 12 is a porous chromium layer covering the surface of the support 11. A porous chromium layer is generally referred to as porous chromium in the field of plating technology, and is a thin layer of chromium with many minute cracks on its surface, and the cracks have narrow openings and wide bottoms. Often exhibits bag-like pores. In the panel of the present invention, the number of cracks (12ij) formed in the porous chromium layer 12 is 5,000 to 50,000/
It is preferable that the cracks exist at a density of approximately 50 to 70 cm.
% is preferable, and the porosity of porous chromium 112 is 10
It is preferable that it is about 45%. FIG. 2 shows a W mirror photograph of the surface of the porous chromium layer. As shown in FIG. 1, fine columnar blocks 13ij of stimulable phosphor can be formed on the surface of such a porous chromium layer by vapor deposition. (13i The average diameter of the columnar blocks 13ij is preferably 1 to 400 μm, and the gap (13ij) may be any distance as long as the fine columnar blocks 13ij are independent of each other, but is preferably 0 to 2011I11 on average. Said 13ij and (
It is preferable that a protective layer 14 is provided on the surface of the photostimulable phosphor [13] on which the 1\I-exhaustible faint fluorescence 13 according to the present invention is formed by 13ij). Further, an adhesive layer for assisting adhesion of the stimulable phosphor between the porous chromium layer and the stimulable phosphor layer, or a reflective layer for stimulable excitation light and/or 11I excitation light, if necessary. Alternatively, an absorbent layer may be provided. FIG. 1(b) shows another example of the panel of the present invention as a sectional view in the thickness direction. In addition, Fig. 1(a) and Fig. 1(
In I)), the same symbols are functionally synonymous with each other. In FIG. 1(b), the crack (12ij) formed in the porous chromium layer 2 has reached the surface W1 of the support 11, and the aI formed by filling the crack (12ij)
Preferably they are present at a density of 50,000-50,000 glands/c to 2 degrees. Also, the height of the fine wire mesh 15 is 1
1 and the thickness of the porous chromium layer 12 preferably have a relationship of 11≧. The fine columnar blocks of stimulable phosphor obtained as described above have a finer diameter than those obtained by method c described in Japanese Patent Application Nos. 59-266912 to 266916. When photostimulable excitation light is incident on the above-mentioned photostimulable phosphor layer having an optically independent fine columnar block structure, the excitation light is repeatedly reflected on the inner surface of the columnar block due to the light guiding effect of the fine columnar block structure and forms a columnar structure. It reaches the bottom of the columnar block without dissipating outside the block. Therefore, the sharpness of images produced by stimulated luminescence can be significantly increased. The thickness of the stimulable phosphor layer 3 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 800 μ'n.
More preferably, it is in the range of 50 to 500 μIn. In the radiation image conversion panel of the present invention, the 111I exhaustible phosphor means that after being irradiated with the first light or high-energy radiation, the It refers to a phosphor that exhibits stimulated luminescence corresponding to the amount of initial light or high-energy radiation irradiation (excitation), but from a practical point of view it is preferably 50%
It is a phosphor that exhibits stimulated luminescence by stimulated excitation light of 0 nm or more. I used in the radiation image conversion panel of the present invention
As a TI exhaustible phosphor, 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 zoTIfi, and X is o, ooi≦x<1 mol96. ), MH8O described in JP-A-48-80488,
:Ax (where A is either o or Dy, and 0.001≦X≦1 mol%), S described in JP-A-48-80489 r
SO<:1. x (However, A is at least one of Dy+Tb and Tm, and 0.001≦x<1 mol%
be. ) phosphor, JP-A-51-298
Na2S O4, Ca S described in No. 89
Phosphor in which at least IM of Mn, Dy and Tb is added to O, BaSO4, etc., JP-A-52-30487
B e O+ L + F + M described in the issue
g Phosphors such as SO4 and CaF2, JP-A-53-
L i 2 B 40 described in No. 39277
? Phosphors such as ', CueAg, etc., JP-A-1987-
L i20 ・(B 2
02) X: Cu (xl, t2<xS3), and tp
L i20- (B 202)X: Cu, Ag (however,
is a phosphor such as 2<xS3), U.S. Patent 3°859.52
Recorded in issue 7fi3#tti7+srs:CetSI[I,
SrS: E u, S +n, L 11202S
Examples include phosphors represented by :Eu, Sm and (Zn, Cd)S:Mn, X (where X is a halogen). In addition, ZnS described in JP-A No. 55-12142
:Cu, Pb phosphor, general formula is BaO・XA 120
): E 11 (however, 0.8≦X≦10), and the general formula is MIIo-xS
io □:A (However, M” is M g + Car
S r r Z n r Cd or Ba and A is Ce
, Tb, Eu, Tu, Pb, T I, B i and Mi]
At least one of the following, × is 0.5≦X≦2.5
It is. ) Alkaline earth gold R silicate M
'ili' fk
10 Su・-Todororu; Bokuko 1 (Ba
MF3 Ca) FX:eEu"l
X Y X y (where X is at least one of B and CI, and XvY
and e are O<x+y≦0.6, ×y≠O and 1, respectively
This number satisfies the condition 0-6≦C≦5×10-2. ) can be mentioned. In addition, the general formula is L no The general formula for the phosphor represented by 0 (represents a number that satisfies 0.1) in JP-A-55-1.2145 is (B a M ''x) F X :yA Heavy -X (However, M''' is Mg + Ca, Sr, Zn and Cdy.
T m + D y r P r +11 o, N
d, Y b and E", X
and y represents a number satisfying the conditions of O≦≦0.6 and 0≦y≦0.2. ) Phosphor expressed by JP-A-55-8
The general formula described in No. 4389 is B aF X :
xCe. yA (where X is at least one of CI, Br and (/I, A is at least one of In, T I, G d, S 1fi and Zr, and X and y are each O <x≦2X10-' and o<y≦5X10-''), JP-A-55-1600'78
The general formula described in the issue is MπF
At least one of d, A is BeO, MgO+Ca
O. Sr○, BaO, ZnO, AI203, Y
203, L a 20 s. I n20 Its IO2, TiO2, ZrO2, G
eO2HS n O2+N b20 s, T n20
at least one of s and TI+02, L n is E
u+Tl), Ce+Tm+Dy+Pr+Ho+NcLY
l], Er, S+n, and Gcl, X is at least one of CI, Br, and ■, and X and y are each 5X10-5≦×≦0.5
and (')<y≦0.2. )
Rare earth element-activated divalent metal fluoronolide phosphor, whose general formula is ZnS:A, (Zn,Cd)S
:A, CdS:A, ZnS:A, X and CdS:A,
X (However, A is Cu r A gHA u H or M n
and X is halogen. ), the general formula (r
) or [I[), general formula (1) xM, (PO,)
2.NX2:l'A general formula (II) M3(P
O,)2・yA (where M and N are each M g +
At least one of Cat S r + B a tZ n and Cd! ! ! l, X is F, CI. At least one of Br+ and ■, A is Eu, Tb. Ce+T+n+Dy+P r+Ho, Nd, Er+S
b,T! +Represents at least one of Mn and Sn. Further, X and y are numbers that satisfy the condition 0<x≦6.0≦y≦1. ), a phosphor represented by the general formula (II
I) or [IV) General formula CIff ] nReX
Co・+nA X' 2: xEu general formula (■) n
ReX co・toAX'z: xEu+yS+n (in the formula, '
Re is at least 1 of La, Gd, Y, and Lu! ! 1
, A represents at least one of alkaline earth metals, Ba, Sr, and Ca, and X and X' represent at least one of F, CI, and Br. Also, X and y are 1X IF'
< x < 3 X 10-', I Xl0-1'< y
It is a number that satisfies the condition < I Xl0-1, and n/+
a is I X 10-'< n/. < 7 Xl0-
1 condition is satisfied. ) Phosphor represented by C' and the general formula % formula %: (However, M is at least one kind of alkali metal selected from Li, Na, Rb, and Cs, and M'' is B
e + M g t Ca + S r t B a
+ Z n + Cd v At least one divalent metal selected from Cu and Ni. M” is S c, Y
, L n, Ce, P r, N d, P 111. S
FIlyE u, G d, T b. Dy+Ho+Er, Tm+Yb, Lu, A I+Gat
and at least one divalent metal selected from In. x, x', and X# are at least one type of halogen selected from F, CI, Br, and ■. Alj:Eu. TbtCe, T+n+Dy, Pr, Ho+Nd, YIg
Er, Gd, LutS ll1e Y v T l r
N at A Fl + is at least one metal selected from Cu and Mg. Also, 8 is a numerical value in the range of 0≦a<0.5, and 1] is a value in the range of 0≦
The numerical value is in the range of b<0.5, and C is a phosphor in the range of O<c≦0.2. In particular, alkali halide phosphors are preferred because they can easily form R-exhaustive phosphor debris using 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 luminescence when irradiated with radiation and then irradiated with stimulated excitation light. The radiation image conversion panel of the present invention may have 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, aluminum, copper, iron, and alloys thereof are used as the metal support. Note that aluminum is convenient for chrome plating. The layer thickness of the support is generally 500μW to 5I
, and handling point #-L t a I-1
'+ 67 Medium] I 1,111 nch -9
+nm F Jk 7. - The porous chromium layer of the support is formed by, for example, plating chromium on the surface of the aluminum support or the surface of the aluminum support on which the base plating has been applied, and then performing a porous treatment. The base plating layer is provided to improve Ti adhesion of the chrome plating layer. For example, zinc, shell, and nickel layers may be plated on the support to a thickness of approximately 0.5 μm, or zinc and nickel may be plated on the support. Each layer is plated with about 0.5μIn in order, or the tsuba and nickel are plated with about 0.5μIn.
It may be plated with about 5μI11. As the chromium plating bath, a chromic acid-sulfuric acid bath or a chromic acid-sodium silicide-sulfuric acid bath is used. In the case of chromic acid-sulfuric acid bath, Cro3tA degree 200-
300g/l, H2SO, 8 degrees 2.0-3.0
FI/9, plating temperature 45-60℃, current density 10-7
It is preferable to set it as 0A/dIII2. In the case of chromic acid-keif/sodium-sulfuric acid bath, Cry, concentration 2
00-300g/Q, Na2s iF 6tn
degree 5-10g/Q SH2SO1 concentration O,]-1,5
g/Q, l Tsuki temperature 50-60''c Current density 30℃
It is preferable to set it as 60A/d1112. The thickness of the chromium plating is preferably about 5 to 300 μm. It is known that a chromium plating layer spontaneously generates a large number of network-like myfloras due to electrodeposition stress generated during the electrodeposition process. By dissolving and expanding this micro rank, a porous chromium layer related to the present invention is formed. Examples of this porosity treatment method include mechanical processing, chemical etching, electrolytic etching, and heating processing. Mechanical processing methods include sandblasting, shishit beaning,
According to Rowlett et al. The chemical etching method is carried out using a mineral acid or a mixed acid thereof.
) is electrolyzed in a bath with additives such as Rum, H2SO, etc. The porous chromium layer formed by the above method may be subjected to heat treatment before forming the stimulable phosphor layer. Further, the heating processing method is a method in which a stimulable phosphor layer is provided on a chrome-coated layer and then heated to grow microcracks. Hydrogen gas generated during plating is adsorbed on the chrome plating layer, and when it is heated, the hydrogen gas expands and expands the microcracks. At the same time, the stimulable phosphor layer on the chromium layer also cracks. occurs. The heat treatment is preferably carried out in vacuum or in the atmosphere at a temperature of 350° C. or higher. In addition, after heat treatment, an additional 10 to 20
A stimulable phosphor layer of μI11 thickness may be deposited. Of the mechanical processing methods, chemical etching methods, electrolytic etching methods and heat processing methods, the etching method and the heat processing method are preferred, and the heat processing method is most preferred. In addition to the porous chromium layer, in the case of providing a fine wire network formed by filling the cracks, that is, in the case of producing a panel having the structure shown in FIG. 1(b), for example, the method described below is used. . As for the support, use something similar to the support described above (the same applies to the base plating), and the thickness of the ROM plating layer described above should be about 5 to 50 μW! preferable. Next, a porous treatment is performed using the above-mentioned chemical etching method or electrolytic etching method to grow microcracks in the chromium plating layer to a depth where the surface of the support is exposed, thereby creating a porous chromium layer. The material for the fine fa network is preferably one that has different crystal conditions and physical properties such as tertiary expansion and/or thermal expansion from the stimulable phosphor, and is preferably a metal for practical purposes. The support having the porous chromium layer on top is made of N a OI
() to remove aluminum oxide adhering to the surface of cracks in the porous chromium layer, and then metal plating, for example, nickel coating, will cause nickel to be electrodeposited preferentially on the cracks. Thin wire t made of nickel
4 is formed. At this time, in order to conveniently deposit the stimulable phosphor as fine columnar blocks on the porous chromium layer, the height of the fine R network is equal to the thickness of the porous chromium layer, but it is preferably larger. Generally, a protective layer for chemically protecting the stimulable phosphor layer group is preferably provided on the surface where the stimulable phosphor layer is exposed. Ha, keep ig! The layer coating liquid may be applied directly onto the stimulable phosphor layer, or a protective layer separately formed in advance may be adhered onto the stimulable phosphor layer. Materials for the protective layer include cellulose acetate, nitrocellulose, and polymethyl methacrylate. Polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene terephthalate, polyethylene, polypropylene 1. Polyvinylidene chloride, nylon, polytetra7)ethylene, polytetra7tethylene-ethylene chloride, tetra7tethylene-hexapropylene copolymer, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-7-chloroethylene A material for the V1 layer, such as a nitrile copolymer, is used. In addition, this protective layer can be formed by vacuum evaporation, sputtering, etc.
S iC=S io 2. It may also be formed by laminating inorganic materials such as S iN and A I□03. Next, the vapor phase deposition method of the stimulable phosphor layer will be explained with reference to v1. There is a vacuum evaporation method as a method of f51. In this method, the support is first placed in a vapor deposition apparatus, and then the inside of the apparatus is evacuated to a degree of vacuum of about 10-' Torr. Next, the temperature was heated to 300 to 500°C using a heater for heating the support.
After cleaning the surface of the support by heating it to 100
℃, and after introducing argon gas etc. to bring the degree of vacuum to about 5 x 1O-6 Torr, apply a stimulable phosphor, such as a rubinium bromide phosphor using thallium as an activator! Deposit until the thickness is approximately 250 μIO. As a result, a stimulable phosphor layer containing no binder is formed, but in the vapor deposition step, it is also possible to co-evaporate using a plurality of resistance heaters or an electron beam. After the vapor deposition is completed, a protective layer is preferably provided on the side of the stimulable phosphor layer opposite to the support, if necessary, to produce the radiation image conversion panel of the present invention. In addition, Ho 1! After forming the stimulable phosphor layer on the layer, a step may be taken in which a support is provided. 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. A second method is a sputtering method. In this method, as in the vapor deposition method, the support is placed in a sputtering device, the inside of the device is once evacuated to a vacuum of about 10'' Torr, and then an inert gas such as Ar or He is used as a sputtering gas. Gas is introduced into the sputtering apparatus and the temperature is increased to 10-, 'Torr.
The gas pressure should be approximately On this layer 12, for example, a stimulable phosphor having a fine columnar block structure is deposited to a desired thickness by sputtering rubidium bromide using thallium as an activator. 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 terded layers each made of a different stimulable phosphor. Alternatively, it is also possible to form a stimulable phosphor layer by sequentially sputtering the tarded materials. After the sputtering is completed, a protective layer is preferably provided on the opposite side of the stimulable phosphor layer from the support side as required in the same manner as in the vacuum evaporation method. . 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 are sputtered simultaneously or sequentially to synthesize a desired stimulable phosphor on a support and simultaneously form a stimulable phosphor layer. It is also possible to form In addition, in the sputtering method, 02
．． Reactive sputtering may be performed by introducing a gas such as H2. Furthermore, in the sputtering method, the object to be deposited (support or protective layer) may be cooled or heated as necessary during sputtering. Another method is the CVD method. This method involves decomposing the target photostimulable phosphor or an organometallic compound containing the photostimulable phosphor raw material with energy such as heat or high-frequency power, thereby forming a binder-free X1ll on a support.
Obtain an exhaustible phosphor layer. FIG. 3(a) shows an example of a stimulable phosphor layer of a radiation image conversion panel of the present invention obtained by a vapor deposition method and the relationship between the amount of stimulable phosphor raw material and radiation sensitivity corresponding to the layer thickness. represents. Since the Ql-stimulable phosphor layer produced by the vapor deposition method according to the present invention does not contain a binder, the amount of stimulable phosphor attached (filling chamber)
is about 2% of the stimulable phosphor layer coated with conventional stimulable phosphor.
Not only is the radiation absorption rate per unit thickness of the stimulable phosphor layer improved, resulting in high sensitivity to radiation, but also the graininess of the image is improved. Furthermore, the stimulable phosphor layer produced by the vapor deposition method has excellent transparency, has high transmittance to stimulated excitation light and stimulated luminescence, and has a thickness of N compared to the conventional stimulable phosphor layer produced by coating. can be made thicker, making it even more sensitive to radiation. An example of the sharpness of the panel of the present invention having a stimulable phosphor layer with a fine columnar block structure obtained as described above is shown in the third example.
It is shown by the characteristic surface KQ31 at 31 in FIG. The panel of the present invention is disclosed in Japanese Patent Application Nos. 59-266912-26[
The structure is finer than the fine columnar block structure described in No. 3916, and due to the light induction effect, the llI exhaustion excitation light is repeatedly reflected on the inner surface of the columnar block and is less likely to be dissipated outside the columnar block. Special request 1987
This is a successor to the tile-shaped addendum designated in No. 266914.As is clear from the comparison with 32 in Figure 3 (1)), which shows the characteristics, the sharpness of the image is improved and the layer thickness of the stimulable phosphor is It is possible to further improve sharpness as . 33 in FIG. 3 shows the characteristics of a conventional panel obtained by dispersing and coating stimulable phosphor particles in a binder. This clearly shows that the image sharpness is excellent. The radiation image conversion panel of the present invention provides excellent sharpness granularity and sensitivity when used in the radiation #X1iI image conversion method shown schematically in FIG. That is, in FIG. 4, 41 is a radiation generating device, 42 is a subject, 43 is a radiation image conversion panel of the present invention, 44 is a stimulated excitation light source,
45 is a photoelectric conversion device that detects stimulated luminescence emitted from the radiation image conversion panel; 4G is a device that reproduces the signal detected by 45 as an image; 47 is a device that displays the reproduced image; 48 is a photoelectric conversion device that detects stimulated luminescence emitted from the radiation image conversion panel; It is a filter that separates excitation light and stimulated luminescence and allows only stimulated luminescence to pass through. It should be noted that the information after 45 may be anything that can reproduce the optical information from 43 as an image in some form, and is not limited to the above. As shown in FIG. 4, the radiation absorption rate ji! The radiation from 41 enters the radiation image conversion panel 43 of the present invention through the subject 42. This incident radiation is absorbed by the stimulable phosphor layer of the panel 43, and its energy is accumulated to form a W product image of the radiation transmission image. Next, this accumulated image is excited with stimulated excitation light from the stimulated excitation light source 44 to emit stimulated luminescence. Since the radiation image conversion panel 43 of the present invention has the columnar block vIt of the stimulable fluorescent phosphor layer, the stimulable excitation light is applied to the stimulable phosphor layer during scanning by the stimulable excitation light. This prevents it from spreading inside. Since the strength 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 45 such as a photomultiplier tube, and an image reproduction device 46
By reproducing the image as an image and displaying it on the image display device 47, a radiographic image of the subject can be observed.

【Example】

Next, the present invention will be explained by examples. Example 1: Using a 1.5 mm thick aluminum plate as a support, the surface of the aluminum plate was bub-polished, then degreased and washed with water.
Chromium was plated to a thickness of about 60 μm in a plating bath with a temperature of 5 g/Ω, a temperature of 60° C., and a current density of 40 A/da2. Next, after washing this with water, Cro 2250g/Q 1H
2S O42゜5g/Q, temperature 60℃, current density 50A
/d! Electrolytic etching was performed using a bath of n2 to a depth of 7
A porous chromium layer with cracks of 0-20 microns was created. Thereafter, the support having the porous chromium layer thereon was washed with water, dried, and placed in a vapor deposition apparatus. Next, the stimulable phosphor R [3r:o, 004
The evaporator was then evacuated to a degree of vacuum of I.times.10-' Torr. Then, the heating temperature was 300 to 500 using a heater for heating the support.
After cleaning the surface of the support by heating it to 100℃
℃ and introduced argon gas to 5 x 10-'
The degree of vacuum was approximately Torr. Next, RbBr is evaporated from the stimulable phosphor RbBr r:o, 004T Q using a resistance heating method to form a stimulable phosphor layer having a fine columnar block structure of RI+Br r:o, 004T Q with a film thickness of approximately 250 μm. A radiation image conversion panel A of the present invention was obtained. Panel A of the present invention obtained in this way has a tube voltage of 8
0K V p)X #i wo10mR Teru Jit I,
Ta, photostimulation is excited with semiconductor laser light (780 nm), the stimulated luminescence emitted from the photostimulable phosphor layer is charged and converted with a photodetector (photomultiplier tube), and this signal is sent to 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 (M T F ) 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 expressed as a relative value, with the radiation image conversion panel A of the present invention being taken as 100. Further, the modulation transfer function (M T F ) is a value when the spatial frequency is 2 cycles/l. Example 2 Using the same support as in Example 1, after pub polishing, degreasing, and water washing, chromium was plated on the support under the same plating conditions as in Example 1. Thereafter, the support having this chromium plating layer on top was washed with water and dried, and the stimulable phosphor RbBr r:o,004TQ was vapor-deposited using the same vapor deposition method as in Example 1, to a film thickness of approximately 250 μm. - After forming the stimulable phosphor layer, this was subjected to heat treatment at about 400° C. in a vacuum to obtain a radiation image conversion panel B of the present invention. 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. Comparative Example 1゜Photostimulable phosphor RbBr r:o, 004T Q 8 i!
111 parts, 1 part by weight of polyvinyl butyral resin, and solvent (
5 parts by weight of cyclohexanone) were mixed and dispersed, and the coating solution for the stimulable phosphor layer was made into IS2. This coating solution was then placed horizontally on a black polyethylene terephthalate film with a thickness of 300 μm as a support. A stimulable phosphor layer with a thickness of 250 μm was formed by applying the stimulable phosphor layer to a substrate and drying it naturally. The comparative panel P thus obtained was evaluated in the same manner as in Example 1, and the results are also listed in Table 1. As is clear from Table 12!2 W&1, the radiation image conversion panels A and B of the present invention had Xls sensitivity approximately twice as high as that of the comparative radiation image conversion panel P, and had excellent image graininess. This is because the radiation image conversion panel of the present invention does not contain a binder in the stimulable phosphor layer, and the filling rate of stimulable phosphor is higher than that of comparative panels, and the X-ray absorption rate is good. It is. In addition, the radiation image conversion panels A and B of the present invention were superior in sharpness even though they had higher X#l sensitivity than the comparative radiation image conversion panel P. This is because the stimulable phosphor layer of the radiation image conversion panel of the present invention has a fine columnar block structure, so that the scattering of the semiconductor laser, which is the stimulable excitation light, in the stimulable phosphor layer is reduced. This is to do so.

【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 images. 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 the drawing]

FIGS. 1(a) and 1(b) are cross-sectional views showing a part of a radiation image conversion panel according to an example of the present invention. FIG. 2 is a micrograph of the surface of a porous chromium layer of a radiation image conversion panel according to an example of the present invention. FIG. 3(a) is a diagram showing the thickness and adhesion amount of the Z stimulable phosphor layer and the sensitivity to radiation on a radiation image conversion panel according to an example of the present invention, and FIG. 3(b) is a diagram showing the spatial frequency and the sensitivity to radiation. FIG. 4 is a diagram showing the relationship with the modulation transfer function (M T F ). FIG. 4 is a schematic diagram of a radiation image conversion device in which the panel of the present invention is installed. It is a figure showing the amount of stimulable phosphor layer formation and the sensitivity to radiation in the conversion panel, (b)
is the stimulable phosphor in the conventional radiation image conversion panel/! y thickness, adhesion amount and spatial frequency are 2 cycles/ml
11 is a diagram showing the modulation transfer function (M T F ) in FIG. 11... Aluminum support 12... Porous chromium layer 13... Stimulable phosphor layer 14... Protective layer 31... Characteristics 32 of the radiation image conversion panel of the present invention Characteristics 33 of the radiation image conversion panel having a fine columnar block structure Characteristics 4 of the conventional radiation image conversion panel
1...Radiation generation VC placement 42...Subject 43...Radiation image conversion panel 44...
・V$ exhaustive excitation light source 45...Photoelectric conversion device 46...Image reproduction device 47...Image display device 48...Filter applicant Roku Konishi Photo Industry Co., Ltd. Figure 3 (1) 9 simple n4 number (1 strong) Figure 4 Figure 5 (b) Hand Thread h'FT Seisha F (Method) 1985 1
February 24th 1, Display of the case Patent Application No. 180706 of 1985 2, Name of the invention Radiographic image conversion panel 3, Person making the amendment Relationship to the case Patent applicant address 1-26 Nishi-Shinjuku, Shinjuku-ku, Tokyo Contact number 2: Konishiroku Photo Industry Co., Ltd., 1 Sakura-cho, Hino-shi, Tokyo 191 (Telephone: 0425-83-152)
1) Patent Part 5, Drawing to be amended 6, Contents of the amendment (1) First, replace Figure 2 with the attached photograph as a substitute for the drawing.

Claims (1)

[Claims] A radiation image conversion panel comprising a porous chromium layer on a metal support and at least one stimulable phosphor layer on the porous chromium layer.