JPH0581671B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a phosphor vapor deposition apparatus,
More specifically, the present invention relates to a phosphor vapor deposition apparatus that is capable of producing a phosphor layer having a substantially constant layer thickness over a large area.

(Background of the Invention) Fluorescent substances have been studied for a long time, and as the search for fluorescent substances has expanded and the elucidation of their fluorescence emission mechanisms and luminescent properties has progressed, warning lights,
A wide range of fields of use have opened up, including fluorescent screens for X-ray photography and displays such as CRTs.

When using these phosphors, phosphor powder obtained by a general phosphor synthesis method including a firing process is sufficiently dispersed in a solvent containing a binder, and then placed in a glass tube or other support. Apply on top. Thereafter, this is dried to remove the solvent and a phosphor layer containing a binder is formed, which is used for various purposes.

Furthermore, detailed studies have been made on the exhaustibility and photostimulability of phosphor afterglow, and in particular, it has been found that when a photostimulable-long afterglow crystalline phosphor is irradiated with light of a wavelength longer than the fluorescence of the phosphor. Attention was paid to the phenomenon in which the brightness of afterglow increases rapidly due to the release of energy from a phosphor that has stored phosphorescence, and the use of stimulable phosphors as an intermediate recording medium for radiographic images was opened up, and furthermore, the intensity of stimulated luminescence increased. Adaptation to recording media is accelerating, such as improvements in the rectangular responsiveness of stimulated luminescence to excitation light, and development of stimulable phosphors.

As this intermediate recording medium, the radiation transmitted through the subject is absorbed by a phosphor, and then this phosphor is excited with light or thermal energy, so that the radiation energy accumulated by the phosphor through the absorption is converted into fluorescence. The fluorescent light is emitted and the fluorescence is detected and imaged. Specifically, for example, US Pat. No. 3,859,527 and JP-A-55-12144 disclose a radiation image conversion method using a stimulable phosphor and using visible light or infrared rays as the 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. Radiation energy corresponding to the radiation transmittance is accumulated to form a latent image, and then this stimulable phosphor layer is scanned with stimulable excitation light to emit the accumulated radiation energy in each part. This is converted into light, and an image is obtained using an optical signal based on the intensity of this light. This final image may be reproduced as a hard copy or on a CRT.

However, in general, radiation image conversion panels having a stimulable phosphor layer have a particle size similar to that of the general phosphor.
The packing density of the stimulable phosphor is low because it is created by applying a dispersion containing a granular stimulable phosphor of about 1 μm to 30 μm and an organic binder onto a support or protective layer and drying it. (Filling rate: 50%), it was necessary to increase the thickness of the stimulable phosphor layer in order to sufficiently increase the radiation sensitivity.

On the other hand, in the radiation image conversion method, the image sharpness 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.

That is, as mentioned above, conventional radiation image conversion panels have a high sensitivity to radiation and image graininess.
Since the sharpness of the image shows an opposite tendency with respect to the layer thickness of the stimulable phosphor layer, the radiation image conversion panel has a certain degree of mutual sacrifice between sensitivity to radiation, graininess, and sharpness. It has been created over time.

Under these circumstances, several methods have been devised to improve the sharpness of radiographic images. For example, the method of mixing white powder into the stimulable phosphor layer of a radiation image conversion panel described in JP-A-55-146447;
In the radiation image conversion panel described in JP-A-55-163500, 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. How to color it, 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.

Incidentally, in recent years, with the development of vacuum technology and thin film forming technology using vacuum technology, attempts have been made to form a phosphor layer using a vapor deposition method, and some methods have already been put into practical use. The phosphor layers formed by these vapor phase deposition methods include CaI;
X-ray image intensifiers using a phosphor layer and thin film EL (electroluminescence) panels using a ZnS;Mn phosphor layer are known. Furthermore, the present applicant has proposed a radiation image conversion panel comprising a stimulable phosphor layer containing no binder in Japanese Patent Application Laid-open No. 73100/1983.

Unlike conventional methods, the phosphor layers formed by these vapor phase deposition methods are formed in a vacuum, so the amount of impurities mixed in is extremely small, resulting in high emission intensity and a phosphor layer with little variation. In addition, it does not contain substances other than the phosphor such as binders, and the phosphor packing density is approximately 100%.
%, so the light emission can be used effectively. Particularly in the case of radiation image conversion panels, since the stimulable phosphor layer does not contain a binder, the filling rate of the stimulable phosphor layer is significantly improved, and the stimulable excitation light in the stimulable phosphor layer is significantly improved. The directivity of stimulated luminescence is improved, the radiation sensitivity of the radiation image conversion panel and the granularity of the image are improved, and at the same time, the sharpness of the image is also improved.

The improvement in directivity is derived from fine columnar crystals formed during the vapor phase deposition process of the stimulable phosphor layer, and has a significant effect on the resulting image.

However, in general, when these phosphor layers are formed by a vapor deposition method, a sputtering method, etc. using a vapor deposition method, variations in the layer thickness of the phosphor layer have become a major problem. Regarding evaporation from a point evaporation source, t/t ₀ = 1/[1+(x/h) ² ] ^2/3 (where t ₀ and t are the distance h from the evaporation source, respectively)
It shows the film thickness at the center of the distant support surface and at a position at a distance x from the center of the support surface. ), so for example, if the distance from the evaporation source is h = 40 cm, and the size of the support is
In the case of 30 cm x 30 cm, the layer thickness at the edge of the support surface is 82% of the center of the support surface, which is 18% thinner than the center of the support surface.

Conventionally, in vapor deposition on a large-area support, operations such as increasing the distance between the support and the evaporation source or rotating the support have been performed in order to make the layer thickness uniform. . However, in the above-mentioned operation, the evaporation efficiency deteriorates significantly, and a vacuum chamber sufficiently large for the support is required. Further, it has been difficult to completely improve the drawback that the variation in layer thickness increases in the peripheral area of the support. Furthermore, as the deposition area became larger, the variation in layer thickness became larger.

Variations in the thickness of the phosphor layer lead to variations in the luminescence intensity, which leads to deterioration in reproducibility when reproducing images. Furthermore, variations in layer thickness greatly affect not only variations in luminous intensity but also image sharpness and graininess, degrading these. Especially in the case of the radiation image conversion panel, 356mm×
Because a panel with a size of 432mm is used,
In conventional methods, it has been difficult to maintain the thickness of the stimulable phosphor layer substantially constant over the entire surface of the panel.

In view of the above, there has been a strong desire for a phosphor vapor deposition apparatus that can form a phosphor layer with a constant layer thickness over a large area.

(Objective of the Invention) An object of the present invention is to provide a phosphor vapor deposition apparatus in which the thickness of the phosphor layer is substantially constant over a large area.

Another object of the present invention is to provide a phosphor vapor deposition apparatus with good phosphor layer formation efficiency and high productivity.

(Structure of the Invention) It is an object of the present invention to include a linear evaporation source disposed so as to be pierced by a straight line a in the longitudinal direction,
A plane B that makes an intersection line b made by the plane A with the support surface C parallel to the straight line a, and makes an intersection angle θ that is practically determined with the plane A in parallel to the intersection line b.
The sheet-shaped support is in contact with the intersection line b
and a support heater that moves in conjunction with the support and heats the support, and the wire is disposed between the linear evaporation source and the support. A slit-shaped regulating member is provided parallel to the intersection line b that regulates the intersection angle between the streamline of the vapor flow from the shaped evaporation source and the support surface C,
The support heated to a set temperature by the support heater repeatedly moves back and forth, and the phosphor is vapor-deposited by a vapor flow regulated by the regulation member from the linear evaporation source. This is achieved by a phosphor vapor deposition apparatus characterized by the following.

The present invention will be explained in detail below.

FIG. 1 shows an overview of the present invention.

FIG. 1a is an explanatory diagram of the relative position and posture of the linear evaporation source and the support, and the movement of the support. In the figure, 11 is a linear evaporation source, which is penetrated by a straight line a in its length direction. Note that the linear evaporation source may be a multi-dimensional evaporation source interposed by the straight line a.

Reference numeral 13 denotes a support, in which a plane A including the straight line a intersects with a plane C of the support 13 at an intersection line b, which is ab. Further, a plane B parallel to the intersection line b intersects with the plane A at an intersection angle θ, and a plane C of the support 13
touches the plane B at a tangent line c and is movable in two directions (arrows in the figure) substantially perpendicular to the intersection line b.
Note that plane B is a plane that touches support surface C at intersection line b.
It may become B′.

The intersection angle θ is practically determined by the streamlines of the steam flow and the shape and position of the streamline regulating member, but is preferably approximately a right angle.

FIG. 1b shows the case where a sheet-like rigid support is used as the support, and FIG. 1c shows the case where a sheet-like flexible support web is used. The present invention is not limited to the shape, material, etc. of the support as long as the support moves in a direction substantially perpendicular to the linear evaporation source. In Figure 1b and c, 1
1 is a linear evaporation source, 12 is a regulating member, 13 is a support, 14 is a deposition area, and 15 is a roller for transporting the support. Note that the regulating member 12 is for making the direction of the vapor flow incident on the support body uniform, and is provided in the vapor deposition apparatus as necessary. Note that by using this, it is possible to align the growth direction of crystals on the support. Here again, the longitudinal direction of the linear evaporation source is the X direction, and the moving direction of the support body is the Y direction.
direction, the X of the phosphor layer deposited on the support
If the amount of evaporation from the linear evaporation source is constant regardless of location, the layer thickness distribution in the direction is determined by the length of the linear evaporation source, and should have a length comparable to the X direction of the support. However, the uniformity of the layer thickness is maintained. On the other hand, the layer thickness distribution of the support in the Y direction is determined by the speed of movement of the support in a direction perpendicular to the linear evaporation source. Since the thickness of the phosphor layer in the X and Y directions can be controlled independently in this way, it is possible to form a phosphor layer having a uniform layer thickness over a large area. The uniform layer thickness here means that when the average of the maximum and minimum layer thicknesses of the phosphor layer is t (μm), the layer thickness distribution over the entire vapor deposition area is t ± 10%.
t (μm), more preferably t±5%t
(μm) is more preferable. Note that it is also possible to provide a desired layer thickness distribution if necessary.

Further, in the present invention, the evaporation source is linear regardless of the type of evaporation method or vapor deposition method, and it is only necessary that the support moves in a direction perpendicular to the evaporation source. However, among the vapor deposition methods, the vapor deposition method and the sputtering method are preferred for the embodiment of the present invention. FIG. 2 shows a configuration diagram based on the present invention when the type of vapor deposition method and the evaporation method are changed. Note that the present invention is not limited to the method shown in FIG. In FIG. 2, (a) shows one-dimensional vapor deposition using a resistance heating method, and (b) shows two-dimensional vapor deposition using two parallel vapor deposition sources using a resistance heating method. Binary vapor deposition is effective in simultaneously vaporizing substances with different vapor pressures to obtain a deposited film with a desired composition. (c) and (d) are the case of electron beam heating evaporation, and (c) is the case where the electron gun integrated with the evaporation source is arranged in a line.
(d) is the case using a piercing type electron gun. The linear evaporation source in the present invention includes not only the evaporation source itself which is linear, but also the case where a plurality of evaporation sources are arranged in a line as represented by (c). In addition, (e) is the case using the high frequency magnetron sputtering method. In FIG. 2, 21 is an evaporation source, 22 is a support, 23 is a deposition region, 24 is an electron beam, 25 is a piercing type electron gun, 26 is a target, 27 is a target electrode, 27a is a magnet, and 27b is an electrode plate (pole).・piece), 28 is a magnetic field.

The present invention has been explained above, but the fact that it is possible to form a phosphor layer having a uniform layer thickness over a large area, which is a feature of the present invention, means that a stimulable phosphor layer that requires a large area can be formed. This is particularly effective in creating a radiation image conversion panel consisting of. The radiation image conversion panel mentioned here is one described as a specific example of the intermediate recording medium, and has a radiation absorption rate and a light conversion rate (hereinafter referred to as "radiation sensitivity").
Needless to say, the image must have high graininess and high sharpness.

However, as mentioned above, the radiation sensitivity, granularity, and sharpness are closely related to the layer thickness of the stimulable phosphor layer, and as the layer thickness increases, the radiation sensitivity and granularity improve. Sharpness decreases. Therefore, by determining the layer thickness, a radiation image conversion panel having radiation sensitivity, graininess, and sharpness depending on the layer thickness can be formed. For this reason, a radiation image conversion panel is required to have a uniform phosphor layer thickness despite its large area. If there is a large difference in the thickness of the phosphor layer, it will affect not only the variation in radiation sensitivity but also the graininess and sharpness of the obtained image, resulting in a decrease in the diagnostic ability of the medical image.

According to the present invention, the non-uniformity of the layer thickness can be eliminated and the image characteristics can be greatly improved.

An apparatus and method for forming a stimulable phosphor layer using an electron beam evaporation method to which the present invention is applied will be described below.

A schematic diagram of the device is shown in Figure 3. Figure 3a is a cross-sectional schematic diagram of an example of the electron beam heating evaporation apparatus based on Figure 2d, and Figure 3b clarifies the positional relationship between the support and the evaporation source in Figure 3a. for the third
This is a view of the vapor deposition apparatus shown in Figure a from directly above.
In the figure, 31 is a bell jar (vacuum tank), 32
33 is a Pierce-type electron gun, 33 is an electron beam emitted from the Pierce-type electron gun, 35 is a crucible containing the stimulable phosphor (evaporation source) 34 to be evaporated, and 311 is a support on which the stimulable phosphor is to be deposited. , 313 is a support holder integrated with the support heater 312 . Here, the crucible 35 has the same length as the width of the support 40, as shown in FIG.
4 to form a linear evaporation source. electron beam 3
3 enters the evaporation source 34 and performs raster scan in the length direction to uniformly evaporate the evaporation source over the length direction. On the other hand, the support body 311 is connected to a support body holder conveyance wire 310 and a support body holder conveyance guide rail 3 which are linked to a motor (not shown).
9 in a direction perpendicular to the linear evaporation source 34. Note that 38 is a steam flow regulating member (slit shape).

In the vapor phase deposition of stimulable phosphor, research by the present inventors revealed that fine columnar crystals grow parallel to the streamline direction of the vapor flow of the stimulable phosphor component. Therefore, it was provided to align the growth direction of the crystals.

By restricting the direction of streamlines in which the vapor flow reaches the panel support surface in this manner, the growth direction of the fine columnar crystals can be aligned at a roughly constant angle with respect to the panel support surface.

Furthermore, by adjusting and selecting the incident direction of streamlines in which the vapor flow reaches the panel support surface, it is possible to control the growth direction of the fine columnar crystals, which is most suitable for stimulating excitation light irradiation and stimulating luminescence focusing. A convenient stimulable phosphor layer can be formed.

The growth direction of the fine columnar crystals is preferably perpendicular to the surface of the panel support when the stimulated excitation light is one-dimensionally irradiated and collected by a light-concentrating member having a one-dimensional condensing surface.

Furthermore, in Fig. 3, 314 is the main valve;
15 is an auxiliary valve, 316 is a leak valve, which operates in conjunction with an exhaust system (not shown) to
It is used to create, maintain, and adjust a predetermined degree of vacuum within the vacuum chamber.

When using the vapor deposition apparatus according to the present invention, the stimulable phosphor to be evaporated is first uniformly melted or formed by pressing or hot pressing, and then charged into a crucible 35 as an evaporation source 34. At this time, it is preferable to perform a degassing treatment.

Further, the evaporation source 34 does not necessarily have to be a stimulable phosphor, and may be a mixture of stimulable phosphor raw materials.

Further, it is preferable that the crucible 35 is cooled using a liquid cooling pipe 36 so that the evaporation source 34 having a uniform composition can be locally heated to increase the temperature in order to evaporate the evaporation source 34 having a uniform composition in a small amount.

After charging the evaporation source 34 into the crucible 35, the support 3
11 is placed facing the crucible. The spacing is approximately 10 cm to 40 cm, depending on the average range of the stimulable phosphor.
taken in cm. Further, the support body 311 is connected to the heater 3
12 to 50°C to 350°C.

Next, operate the main valve 314, etc. to remove the gas inside the bell jar 31 and reduce the temperature to 10 ^-4 Torr~
Bring to a vacuum level of about 10 ^-6 Torr. At this time, an inert gas such as argon may be mixed.

Next, after adjusting the position of the adjusting plate 38 to determine the intersection angle between the streamline of the steam flow and the surface of the support, the piercing electron gun 3 is moved while the support is moved left and right at a constant speed.
2, an electron beam 33 is incident on a local part of the evaporation source 34 to evaporate a small amount, and the evaporation is proceeded while monitoring the evaporation rate and the evaporation thickness by the film thickness monitor 37, and when a predetermined thickness is reached, the evaporation is prevented.

Incidentally, a plurality of crucibles containing different evaporation sources 34 may be installed in the bell jar 31, and the crucibles may be sequentially deposited to form a deposited layer consisting of a plurality of types of stimulable phosphors.

Furthermore, in the vapor deposition method, the object to be vapor deposited (support or protective layer) may be cooled or heated as necessary during vapor deposition. Furthermore, after the vapor deposition is completed, the stimulable phosphor layer may be heat-treated. Further, in the vapor deposition method, reactive vapor deposition may be performed by introducing gases such as O ₂ and H ₂ as necessary.

The thickness of the stimulable phosphor layer obtained by the above vapor deposition method varies depending on the radiation sensitivity of the intended radiation image conversion panel, the type of stimulable phosphor, etc., but is within the range of 30 μm to 1000 μm. It is preferably selected from the range of 40 μm to 800 μm.

If the layer thickness of the stimulable phosphor layer is less than 30 μm, the radiation absorption rate will be extremely reduced, the radiation sensitivity will deteriorate, the graininess of the image will deteriorate, and the stimulable phosphor layer will become transparent. This is not preferable because the lateral spread of the stimulable excitation light in the stimulable phosphor layer increases significantly and the sharpness of the image tends to deteriorate.

In addition, in manufacturing radiation image conversion panels,
The deposition rate of the stimulable phosphor layer varies depending on the stimulable phosphor and the intended characteristics, but is from 0.01 μm/min.
The speed is preferably 1000 μm/min, more preferably 0.1 μm/min to 100 μm/min. If the deposition rate is less than 0.01 μm/min, the productivity of the radiation image conversion panel will be low, which is not preferable. Further, if the deposition rate exceeds 1000 μm/min, it is difficult to control the deposition rate, which is not preferable.

In a radiation image conversion panel, a stimulable phosphor is a stimulable phosphor that is stimulated optically, thermally, mechanically, chemically, or electrically (stimulated excitation) after being irradiated with the first light or high-energy radiation. refers to a phosphor that exhibits stimulated luminescence corresponding to the amount of initial light or high-energy radiation irradiation; however, from a practical standpoint, it is preferably a phosphor that exhibits stimulated luminescence by stimulated excitation light of 500 nm or more. It is. Examples of the stimulable phosphor used in the radiation image conversion panel of the present invention include BaSO ₄ :Ax described in JP-A-48-80487.
(However, A is at least one of Dy, Tb and Tm.
species, and x is 0.001≦x<1 mol%. ), the phosphor described in JP-A-48-80488
MgSO ₄ :A phosphor represented by Ax (where A is either Ho or Dy, and 0.001≦x≦1 mol%), described in JP-A-48-80489. SrSO ₄ :Ax (A is Dy, Tb and Tm
At least one of the following, and x is 0.001≦x<
It is 1 mol%. ), Na ₂ SO ₄ described in JP-A-51-29889,
Phosphor made by adding at least one of Mn, Dy and Tb to CaSO ₄ , BaSO _4, etc., JP-A-1987-
Phosphors such as BeO, LiF, MgSO ₄ and CaF ₂ described in No. 30487, phosphors such as Li ₂ B ₄ O ₇ :Cu, Ag described in JP-A-53-39277, JP-A-53-39277, etc. Akira
Li ₂ O・(B ₂ O ₂ ) described in No. 54-47883
x: Cu (where x is 2<x≦3), and Li ₂ O・
(B ₂ O ₂ ) x: Phosphor such as Cu, Ag (where x is 2<x≦3), as described in U.S. Patent No. 3,859,527
SrS: Ce, Sm, SrS: Eu, Sm, La ₂ O ₂ : Eu,
Examples include phosphors represented by Sm and (Zn, Cd)S:Mn, x (where x is a halogen). Also, ZnS:Cu,Pb described in JP-A-55-12142
Phosphor, the general formula is BaO・xAl ₂ O ₃ :Eu (however, 0.8
≦x≦10), and the general formula is M〓O・xSiO ₂ :A (however, M〓
is Mg, Ca, Sr, Zn, Cd or Ba and A is Ce,
At least one of Tb, Eu, Tm, Pb, Tl, Bi, and Mn, and x satisfies 0.5≦x<2.5. )
Examples include alkaline earth metal silicate phosphors represented by: In addition, the general formula is (Ba ₁ −x−yMgxCay)FX:eEu ₂ ⁺ (However, X is at least one of Br and Cl, and x, y, and e are each O<x+y≦
0.6, a number that satisfies the following conditions: xy≠ and 10 ⁻⁶ ≦e≦5×10 ⁻² . ) The general formula of the alkaline earth fluorohalide phosphor described in JP-A-55-12144 is LnOX:xA (However, Ln represents at least one of La, Y, Gd, and Lu. , X represents Cl and/or Br, A represents Ce and/or Tb, and x represents a number satisfying O<x<0.1), described in JP-A-55-12145. The general formula is (Ba ₁ −xM〓x)FX:yA (where M〓 is at least one of Mg, Ca, Sr, Zn, and Cd, and X is Cl, Br, and I. A is Eu, Tb, Ce, Tm,
At least one of Dy, Pr, Ho, Nd, Yb and Er, x and y are O≦x≦0.6 and O≦y≦
Represents a number that satisfies the condition of 0.2. ), the general formula described in JP-A-55-84389 is BaFX:xCe,yA (where X is at least one of Cl, Br and I, and A is In, Tl). , Gd, Sm and Zr, and x and y
are O<x≦2×10 ^-1 and O<y≦5×, respectively.
10 ^-2 . ) Phosphor expressed by JP-A-1983-
The general formula described in No. 160078 is M〓FX・xA:yLn (However, M〓 is Mg, Ca, Ba, Sr, Zn and Cd
At least one of the following, A is BeO, MgO,
CaO, SrO, BaO, ZnO, Al ₂ O ₃ , Y ₂ O ₃ ,
La ₂ O ₃ , In ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , GeO ₂ ,
At least one of SnO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ and ThO _{2 ,} Ln is Eu, Tb, Ce, Tm, Dy, Pr,
At least one of Ho, Nd, Yb, Er, Sm, and Gd, X is at least one of Cl, Br, and I, and x and y are each 5×
The number satisfies the following conditions: 10 ^-5 ≦x≦0.5 and O<y≦0.2. ) rare earth element-activated divalent metal fluorohalide phosphor, whose general formula is ZnS:A,
CdS:A, (Zn,Cd)S:A, ZnS:A, x and
Cds: A phosphor represented by A, X (where A is Cu, Ag, Au or Mn, and X is a halogen),
Any of the following general formulas described in JP-A-57-148285 xM ₃ (PO ₄ ) ₂・NX ₂ :yA M ₃ (PO ₄ ) ₂ :yA (where M and N are Mg, respectively) Ca, Sr,
At least one of Ba, Zn and Cd, X is F,
At least one of Cl, Br and I, A is Eu,
Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er,
Represents at least one of Sb, Tl, Mn and Sn. Also, x and y are O<x≦6, O≦y≦1
This is a number that satisfies the condition. ) phosphor,
Any of the following general formulas nReX ₃・mAX′ ₂ :xEu nReX ₃・mAX′ ₂ :xEu, ySm (wherein, Re is at least one of La, Gd, Y, and Lu, and A is an alkaline earth metal. , Ba, Sr, Ca
At least one of them, X and X' represent at least one of F, Cl, and Br. Also, x and y are
1×10 ^-4 <x<3×10 ^-1 , 1×10 ^-4 <y<1×
It is a number that satisfies the condition 10 ^-1 , and n/m is 1×
The condition 10 ^-3 <n/m<7×10 ^-1 is satisfied. ), and the following general formula M〓x・aM〓X′ ₂・bM〓X″ ₃ :cA (However, M〓 is at least one kind selected from Li, Na, K, Rb, and Cs. is an alkali metal,
M〓 is Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu and
At least one divalent metal selected from Ni. M〓 is Sc, Y, La, Ce, Pr, Nd, Pm,
Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb,
At least one trivalent metal selected from Lu, Al, Ga, and In. X, X′ and X″ are F, Cl, Br
and at least one halogen selected from I. A is Eu, Tb, Ce, Tm, Dy, Pr, Ho,
Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na,
At least one metal selected from Ag, Cu, and Mg.

Moreover, a is a numerical value in the range of O≦a<0.5,
b is a numerical value in the range O≦b<0.5, and c is O<
It is a numerical value in the range of 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 vapor deposition and sputtering.

However, the stimulable phosphors used in radiation image conversion panels are not limited to the phosphors mentioned above, but are phosphors that exhibit stimulated luminescence when irradiated with radiation and then irradiated with stimulable excitation light. Any phosphor may be used.

Further, the radiation image conversion panel 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. Further, the stimulable phosphors contained in each stimulable phosphor layer may be the same or different.

Various polymeric materials, glass, metals, etc. are used as supports for radiation image conversion panels, including cellulose acetate film, polyester film, polyethylene terephthalate film, polyamide film, polyimide film,
Preferred are plastic films such as triacetate films and polycarbonate films, metal sheets such as aluminum sheets, iron sheets, and steel sheets, and metal sheets having a coating layer of the metal oxide.

The surface of these supports may be smooth,
A matte surface may be used for the purpose of improving adhesion to the stimulable phosphor layer. In addition, the surface of the support is
It may be an uneven surface 41 as shown in figure a, or b
It may also be a structure in which isolated tile-like plates 43 are laid out as shown in FIG. In the case of FIG. 4a, the stimulable phosphor layer has an uneven surface 4 as shown in the cross-sectional view of FIG. 4c.
Since the image is subdivided by 1, the sharpness of the image is further improved. In the case of FIG. 4b, the stimulable phosphor layer is deposited while maintaining the contour of the tile-like plate of the support, so that the stimulable phosphor layer is deposited as shown in FIG. 4d.
As shown in the cross-sectional view, the image is composed of columnar blocks 45 of stimulable phosphor separated by cracks 46, thereby further improving the sharpness of the image.

Furthermore, these supports may be provided with a subbing layer on the surface on which the stimulable phosphor layer is provided, for the purpose of improving adhesion to the stimulable phosphor layer. Although the layer thickness of these supports varies depending on the material of the support used, it is generally 80 μm to 2000 μm, and more preferably 80 μm to 1000 μm from the viewpoint of handling.

In a radiation image conversion panel, a layer for physically or chemically protecting the stimulable phosphor layer is generally provided on the opposite side of the stimulable phosphor layer to the side on which the support is provided. A protective layer may also be provided. 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. Good too. As the material for the protective layer, usual materials for the protective layer such as cellulose acetate, nitrocellulose, polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene terephthalate, polyethylene, vinylidene chloride, and nylon are used. In addition, this protective layer is made of Sic, SiO ₂ ,
It may also be formed by laminating inorganic materials such as SiN and Al ₂ O ₃ . The thickness of these protective layers is generally 0.1μm
The thickness is preferably about 100 μm.

(Example) Next, a method for manufacturing a radiation image conversion panel will be described as a specific usage example of the phosphor vapor deposition apparatus according to the present invention.

As a support, a chemically strengthened glass measuring 356 mm x 432 mm x 1 mm was placed in the electron beam heating vapor deposition apparatus shown in FIG. 3a. Further, an RbBr:Tl stimulable phosphor was placed in the crucible 35 as a stimulable phosphor to be evaporated.

Move the steam flow regulating plate 38 so that the angle of intersection between the streamline of the steam flow and the surface of the support is approximately a right angle.
A slit was positioned directly above the crucible. At this time,
The distance between the crucible and the support was 30 cm, the distance between the regulating plate and the crucible was 25 cm, and the width of the slit was 3 cm. The details of the positional relationship among the support, the crucible, and the adjustment plate are as shown in FIG. 3b.

Next, exhaust the inside of the bell gear 31 and
A vacuum level of 10 ^-6 Torr was maintained. In addition, the support
It was heated to 150°C and held at this temperature.

Next, while reciprocating the support back and forth from side to side at a speed of 50 cm/min, the electron beam 33 from the piercing electron gun 32 is scanned and incident on the surface of the evaporation source 34 in a raster pattern, thereby continuously depositing the stimulable phosphor. evaporated.

The deposition was performed while monitoring the deposition rate and deposition thickness using a film thickness monitor, and the deposition rate was set at 5 μm/min.

Vapor deposition was terminated when the thickness of the stimulable phosphor layer reached 200 μm, and a radiation image conversion panel was obtained using the manufacturing apparatus of the present invention, which was composed of a support and a stimulable phosphor layer.

The layer thickness distribution of the stimulable phosphor layer in the radiation image conversion panel thus obtained was ±4% and was substantially uniform over the entire surface of the radiation image conversion panel. As a result, by using this radiographic image conversion panel for diagnosis, it was possible to obtain radiographic images with excellent graininess and sharpness and high diagnostic ability.

(Effects of the Invention) According to the present invention, it is possible to form a phosphor layer with a substantially constant layer thickness over a large area, and furthermore, it is possible to form a phosphor layer with high film formation efficiency and high productivity. It became possible to form In particular, the effects of the present invention will become even more useful if used to form a stimulable phosphor layer in a radiation image conversion panel that requires a large area.

The present invention has extremely large effects and is industrially useful.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a linear evaporation source and a support according to the present invention, and FIG. 2 is an example of application of the present invention to various vapor deposition methods. FIG. 3 is an explanatory diagram of a stimulable phosphor vapor deposition apparatus to which the present invention is applied, and FIG. 4 is a diagram illustrating an example of a support surface suitable for depositing a stimulable phosphor.

Claims (1)

[Scope of Claims] 1 A linear evaporation source is provided whose longitudinal direction is penetrated by a straight line a, and if a plane A including the straight line a intersects a support surface C with a line b that is parallel to the straight line a. and a movement in which a sheet-shaped support is reciprocated in a substantially perpendicular direction with respect to the intersection line b, in contact with a plane B that is parallel to the intersection line b and makes a practically determined intersection angle θ with the plane A. and a support heater that moves in conjunction with the support to heat the support, and a vapor flow from the linear evaporation source is provided between the linear evaporation source and the support. A slit-shaped regulating member parallel to the intersection line b is provided to regulate the intersection angle between the line and the support surface C, and the support heated to a set temperature by the support heater repeatedly moves back and forth. A phosphor vapor deposition apparatus characterized in that the phosphor is vapor-deposited by a vapor flow regulated by the regulating member from the linear evaporation source.