JP2006274308A - Phosphor sheet manufacturing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phosphor sheet manufacturing apparatus capable of manufacturing a phosphor sheet which is uniform in a growth state of a columnar crystal in a phosphor layer and is free of unevenness in image quality. <P>SOLUTION: The apparatus has a vacuum chamber 12, a vacuum evacuation means for evacuating the inside of the vacuum chamber through an exhaust port disposed on its side face, a resistance heating manuscript which heats a deposition material of a stimulable phosphor layer housed is a vessel by resistance heating and emits the vapor of the deposition material from an aperture of the vessel, a substrate holding means 14 which holds the substrate above the resistance heating means, and a gas introducing means which introduces an inert gas into the vacuum chamber via at least one gas introducing port in order to adjust the vacuum degree in the vacuum chamber for the purpose of regulating the vacuum intensity in the vacuum chamber during the deposition of the phosphor layer. The apparatus is provided with the introducing ports to prevent the first region formed by linearly connecting the edges of the gas introducing ports 60a and 62a and the edge of the exhaust port and the second region formed by linearly connecting the edge of the aperture of the vessel of the resistance heating means and the edge of a substrate S from intersecting with each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a phosphor sheet manufacturing apparatus for forming a phosphor layer on a surface of a substrate by vacuum deposition in a manufacturing process of a phosphor sheet used for recording (photographing) a radiographic image in computed radiography (CR) or the like. In particular, the present invention relates to a phosphor sheet manufacturing apparatus capable of manufacturing a phosphor sheet having a uniform growth state of columnar crystals in a phosphor layer made of columnar crystals and having no image quality unevenness.

  When irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.), a part of this radiation energy is accumulated, and then irradiated with excitation light such as visible light, Phosphors that exhibit stimulated emission according to the stored energy are known. This phosphor is called a storage phosphor (stimulable phosphor) and is used for various applications such as medical applications.

As an example, radiation image information recording using a sheet (hereinafter, referred to as a phosphor sheet (also referred to as a radiation image conversion sheet)) having a layer made of this stimulable phosphor (hereinafter referred to as a phosphor layer). A reproduction system is known, and is put into practical use as, for example, FCR (Fuji Computed Radiography).
In this system, radiation image information of a subject such as a human body is recorded on a phosphor sheet (phosphor layer), and after recording, the phosphor sheet is irradiated with excitation light to generate stimulated emission light. The emitted light is photoelectrically read to obtain an image signal, and an image reproduced based on the image signal is output as a radiation image of a subject to a display device such as a CRT or a recording material such as a photographic photosensitive material.

Such a phosphor sheet is usually prepared by dispersing a powder of a stimulable phosphor in a solvent containing a binder or the like, and applying the paint to a glass or resin sheet-like support, Created by drying.
On the other hand, a phosphor sheet in which a phosphor layer is formed on a support by a physical vapor deposition method (vapor deposition method) such as vacuum vapor deposition is also known. Since the phosphor layer produced by vapor deposition is formed in a vacuum, there are few impurities, and since there are almost no components other than the storage phosphor such as a binder, there is little variation in performance, and the luminous efficiency is low. It has excellent properties of being very good. Various methods for producing a phosphor sheet (radiation image conversion panel) by such physical vapor deposition have been proposed (see Patent Documents 1 to 3).

  In Patent Document 1, a ratio (Vn / Vc) between the flow rate Vn of the inert gas introduced into the vapor deposition apparatus and the volume Vc in the vapor deposition apparatus is defined, and a medium degree of vacuum (about 0.05 to A manufacturing method of a radiation image conversion panel which forms a phosphor layer at 10 Pa) is disclosed.

  In Patent Document 2, a stimulable phosphor layer is vapor-deposited on a substrate in a vapor deposition apparatus having an exhaust port and a gas introduction port for introducing a predetermined amount of inert gas into the apparatus. Discloses a method of manufacturing a radiation image conversion panel formed with a film thickness of 50 μm or more. In the manufacturing method of the radiation image conversion panel of Patent Document 2, the substrate and the evaporation source are arranged to face each other, a straight line connecting the center of the exhaust port and the gas introduction port passes between the substrate and the evaporation source, and When the straight line is projected onto the substrate surface, the exhaust port and the gas inlet port are arranged so that the straight line always passes through the substrate, and the vapor flow generated by heating of the evaporation source intersects with the gas flow, so A phosphor layer is formed.

Further, Patent Document 3 discloses a vacuum deposition apparatus that can not only adjust the crystal orientation of the needle to a desired level but also affect the microscopic dimensions of the needle.
In the vacuum vapor deposition apparatus of Patent Document 3, the vapor deposition source is disposed in the vacuum container so as to face the substrate, and a vapor jet is generated from the vapor deposition source toward the substrate. The substrate also rotates around the axis. Ar gas is used as an inert gas during vacuum deposition, and the temperature of Ar gas flowing into the vacuum deposition apparatus is kept at 0 ° C to 100 ° C. This Ar gas is introduced into the vacuum vessel through the control valve, and first collides with the baffle plate and is not directly introduced into the vapor jet. This Ar gas cools both the vapor and the substrate before being deposited in the vacuum deposition apparatus.

JP 2005-37377 A JP 2004-123968 A JP 2001-249198 A

In the medium vacuum region (0.1 to 10 Pa), the introduced gas behaves as a viscous flow. For this reason, in a general phosphor sheet manufacturing apparatus using vacuum deposition, when a gas inlet is provided near the evaporation source, a gas pressure distribution is generated in the evaporation field generated by the evaporation source, which causes growth of columnar crystals in the phosphor layer. Variation will occur. As a result, there is a problem that image quality unevenness occurs in the manufactured phosphor sheet.
For this reason, Patent Document 1 defines a ratio (Vn / Vc) between the flow rate Vn of the inert gas introduced into the vapor deposition apparatus and the volume Vc in the vapor deposition apparatus, but the inert gas. Is not considered to behave as a viscous flow. For this reason, a phosphor sheet without image quality unevenness is not always obtained.

  Moreover, in the manufacturing method of the radiographic image conversion panel of patent document 2, the vapor flow generated by the heating of the evaporation source intersects the gas flow of the inert gas. For this reason, gas pressure distribution is generated in the vapor flow, and the growth of columnar crystals in the photostimulable phosphor layer varies. As a result, there is a problem that image quality unevenness occurs in the manufactured phosphor sheet.

  Furthermore, also in the vacuum evaporation apparatus of Patent Document 3, Ar gas is for cooling both the vapor jet and the substrate, and does not suppress the generation of gas pressure distribution of the vapor jet (evaporation field). For this reason, a phosphor sheet without image quality unevenness is not necessarily obtained.

  An object of the present invention is to eliminate the problems based on the prior art, and to produce a phosphor sheet in which the growth state of the columnar crystals in the phosphor layer made of columnar crystals is uniform and there is no image quality unevenness. It is to provide a manufacturing apparatus.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a phosphor sheet manufacturing apparatus for forming a storage phosphor layer on a surface of a sheet-like substrate by vacuum deposition, the vacuum chamber, and the vacuum A vacuum exhaust means for exhausting the inside of the chamber through an exhaust port provided on a side surface of the vacuum chamber, and a film forming material for the stimulable phosphor layer housed in the container are heated by resistance heating, A resistance heating means for releasing the vapor of the film forming material from the opening; a substrate holding means for holding the substrate above the resistance heating means; and during deposition of the phosphor layer, In order to adjust the degree of vacuum, gas introduction means for introducing an inert gas into the vacuum chamber through at least one gas introduction port, an edge portion of the gas introduction port and an edge portion of the exhaust port And linearly So that the first region formed by connecting the edge of the opening of the container of the resistance heating means and the edge of the substrate linearly does not intersect with each other. The present invention provides a phosphor sheet manufacturing apparatus provided with the gas inlet.

  According to a second aspect of the present invention, there is provided a phosphor sheet manufacturing apparatus for forming a storage phosphor layer on a surface of a sheet-like substrate by vacuum deposition, wherein the vacuum chamber and the vacuum chamber are filled with the vacuum. Vacuum evacuation means for evacuating through an exhaust port provided on the side surface of the chamber, and the film forming material of the stimulable phosphor layer housed in the container are heated by resistance heating, and the film is formed from the opening of the container In order to adjust the degree of vacuum in the vacuum chamber during the formation of the phosphor layer, the resistance heating means for releasing the vapor of the material, the substrate holding means for holding the substrate above the resistance heating means And a gas introducing means for introducing an inert gas into the vacuum chamber through at least one gas inlet, and a diffusion plate provided above the gas inlet and diffusing the inert gas. There is provided a phosphor sheet manufacturing apparatus according to claim.

  In the present invention, the first region formed by linearly connecting the edge of the gas inlet and the edge of the exhaust port, the edge of the opening of the container of the resistance heating means, It is preferable that the gas inlet is provided so as not to intersect with a second region formed by linearly connecting the edge of the substrate.

Further, in the present invention, when there are a plurality of the gas introduction ports, the gas introduction unit allows the vapor pressure of the film forming material obtained by the resistance heating unit to be constant from the gas introduction ports. It is preferable to form the stimulable phosphor layer by adjusting the gas introduction amount.
Further, in the present invention, when there are a plurality of the gas inlets, the amount of gas introduced into the gas inlet closer to the exhaust outlet is made larger than the amount of gas introduced into the gas inlet farther from the exhaust outlet. It is preferable to form the storage phosphor layer.

Furthermore, in this invention, it is preferable to have further provided the diffusion plate provided above the said gas inlet and diffusing the said inert gas.
In the present invention, it is preferable that the diffusion plate has a plurality of holes.
Furthermore, in the present invention, it is preferable that the plurality of holes provided in the diffusion plate include those having different diameters.
Furthermore, in the present invention, the apparatus further includes at least one measuring unit that measures the degree of vacuum in the vacuum chamber, and the gas introducing unit determines the degree of vacuum measured by the measuring unit. It is preferable to form the stimulable phosphor layer by adjusting the amount of gas introduced from the gas inlet.

In the present invention, it is preferable to further include a substrate transport unit that transports the substrate together with the substrate holding unit through a linear transport path.
In the present invention, when the substrate is transported along a linear transport path, the edge of the substrate in the second region is the edge in the entire range in which the substrate is transported in a straight line.
Furthermore, in the present invention, it is preferable that a plurality of the containers in the resistance heating unit are arranged side by side in a direction orthogonal to a substrate transfer direction by the substrate transfer unit.

  According to the phosphor sheet manufacturing apparatus of the first aspect of the present invention, the vacuum exhaust means for exhausting through the exhaust port provided on the side surface of the vacuum chamber, and the film formation of the stimulable phosphor layer housed in the container Resistance heating means for heating the material by resistance heating and releasing vapor of the film forming material from the opening of the container, and gas introduction means for introducing an inert gas into the vacuum chamber through at least one gas introduction port are provided. The first region formed by linearly connecting the edge of the gas introduction port and the edge of the exhaust port, and the edge of the opening of the container of the resistance heating means and the edge of the substrate are linearly connected. By providing the gas inlet at a position where it does not intersect with the second region formed by the connection, the flow of the inert gas introduced into the vacuum chamber through the opening of the gas inlet nozzle causes the vapor of the film forming material to flow. Disturbance in the second region without crossing Less. Thereby, the vapor | steam of uniform film-forming material can be exposed to a board | substrate. For this reason, the columnar crystals constituting the phosphor layer can be uniformly grown on the surface of the substrate, the film thickness distribution is high, and the excellent photostimulable light emission characteristics and image sharpness are excellent. It is possible to obtain a high-quality phosphor sheet having no phosphor image quality and having a phosphor layer.

  Further, according to the phosphor sheet manufacturing apparatus of the second aspect of the present invention, the vacuum exhaust means for exhausting through the exhaust port provided in the side surface of the vacuum chamber, and the stimulable phosphor layer stored in the container Resistance heating means for heating the film forming material by resistance heating and releasing vapor of the film forming material from the opening of the container, and gas introducing means for introducing an inert gas into the vacuum chamber through at least one gas introduction port And a diffusion plate for diffusing the inert gas above the gas introduction port, the flow of the inert gas introduced into the vacuum chamber through the opening of the gas introduction nozzle is changed to the vapor of the film forming material. And the disturbance in the second region is reduced. Thereby, the vapor | steam of uniform film-forming material can be exposed to a board | substrate. For this reason, the columnar crystals constituting the phosphor layer can be uniformly grown on the surface of the substrate, the film thickness distribution is high, and the excellent photostimulable light emission characteristics and image sharpness are excellent. It is possible to obtain a high-quality phosphor sheet having no phosphor image quality and having a phosphor layer.

Hereinafter, the phosphor sheet manufacturing apparatus of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
Fig.1 (a) is typical sectional drawing which shows the phosphor sheet manufacturing apparatus based on the 1st Example of this invention, (b) is a model of the phosphor sheet manufacturing apparatus shown to Fig.1 (a). FIG.

The phosphor sheet manufacturing apparatus 10 (hereinafter referred to as the manufacturing apparatus 10) shown in FIG. 1 evaporates separately a material that becomes a stimulable phosphor (matrix) and a material that becomes an activator (activator). This is an apparatus for producing a (storable) phosphor sheet by forming a layer made of a stimulable phosphor (hereinafter referred to as a phosphor layer) on the surface of the substrate S by binary vacuum deposition.
Such a manufacturing apparatus 10 basically includes a vacuum chamber 12, a substrate holding and transporting mechanism 14, a heating evaporation unit 16, a vacuum pump (evacuation unit) 18, an RF matching box 20, and a gas introduction nozzle. 60. Needless to say, the manufacturing apparatus 10 of the present invention may have various components other than those described above, which are included in known vacuum deposition apparatuses. For example, a vacuum gauge (measuring means) for measuring the degree of vacuum in the vacuum chamber 12 is provided.

  The present invention is not limited to a binary vacuum deposition apparatus as shown in the illustrated example, and may be an apparatus for performing a single vacuum deposition in which all film forming materials are mixed and stored in an evaporation source. Alternatively, an apparatus that performs ternary or higher vacuum vapor deposition may be used, but a binary or higher multi-layer vacuum vapor deposition apparatus that stores a plurality of film forming materials in separate evaporation sources is preferable.

In the illustrated example, as a preferred example, cesium bromide (CsBr) as a phosphor component and europium bromide (EuBr _x (x is usually 2 to 3) as an activator component, Is used as a film forming material, and binary vacuum deposition is performed by resistance heating to form a phosphor layer made of CsBr: Eu, which is a stimulable phosphor, on a substrate S to produce a phosphor sheet. To do.
In addition, the manufacturing apparatus 10 having the gas introduction nozzle 60 for introducing an inert gas during film formation preferably introduces the gas while exhausting the interior of the vacuum chamber 12 to a high degree of vacuum. An inert gas is introduced by a nozzle 60 to make the inside of the vacuum chamber 12 have a degree of vacuum of about 0.1 Pa to 10 Pa (hereinafter referred to as a medium vacuum). (Cesium bromide and europium bromide) are evaporated by heating, and the substrate S is conveyed linearly by the substrate holding and conveying mechanism 14 (hereinafter referred to as linear conveyance), and the phosphor layer is formed on the substrate S by vacuum deposition. Do the membrane.

In the present invention, as the storage phosphor (stimulable phosphor) to be formed, various materials other than CsBr: Eu can be used. As an example, an alkali halide storage phosphor represented by the general formula “M ^I X · aM ^II X ′ ₂ · bM ^III X ″ ₃ : cA” disclosed in JP-A-57-148285 is preferred. Illustrated.
(In the above formula, M ^I is at least one selected from the group consisting of Li, Na, K, Rb and Cs, and M ^II is Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu and at least one trivalent metal selected from the group consisting of Ni, M ^III is, Sc, Y, La, Ce , Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, At least one trivalent metal selected from the group consisting of Tm, Yb, Lu, Al, Ga and In, and X, X ′ and X ″ are selected from the group consisting of F, Cl, Br and I A is from Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu, Bi, and Mg. At least one selected from the group consisting of . Also, a 0 ≦ a <0.5, a 0 ≦ b <0.5, a 0 ≦ c <0.2.)

  In addition, U.S. Pat. No. 3,859,527, JP-A-55-12142, 55-12144, 55-12145, 57-148285, and 56-116777. The stimulable phosphors disclosed in the publications such as Nos. 58-69281 and 59-75200 are also preferably exemplified.

In particular, the alkali halide accumulative phosphor is preferably exemplified in terms of photostimulable luminescence characteristics, sharpness of a reproduced image, and the effect of the present invention can be suitably expressed, and in particular, M ^I is at least at least. Alkali halide storage phosphors containing Cs, X containing at least Br, and A being Eu or Bi are preferred, and among these, “CsBr: Eu” is particularly preferred.

The substrate S is not particularly limited, and various sheet-like substrates used in phosphor sheets, such as glass, ceramics, carbon, aluminum, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), and polyimide, All are available.
In the illustrated example, a rectangular substrate S is used as an example.

  The vacuum chamber 12 is a known vacuum chamber (bell jar, vacuum chamber) that is formed of iron, stainless steel, aluminum, or the like and is used in a vacuum deposition apparatus.

A vacuum pump 18 is connected to the side surface 12b of the vacuum chamber 12 via a diffuser 18a. For example, an oil diffusion pump is used as the vacuum pump 18. In addition, the vacuum pump 18 is not specifically limited, The various pumps utilized with the vacuum evaporation system can be utilized if the required ultimate vacuum degree can be achieved. As an example, a cryopump, a turbomolecular pump, or the like can be used, and a cryocoil or the like may be used in combination as an auxiliary. In the manufacturing apparatus 10 for forming the phosphor layer described above, the ultimate vacuum in the vacuum chamber 12 is preferably 8.0 × 10 ⁻⁴ Pa or less.

  Further, the RF matching box 20 is for performing plasma cleaning or the like on the surface of the substrate S prior to the formation (vacuum deposition) of the phosphor layer.

The gas introduction nozzle 60 is also a known gas introduction means used in a vacuum vapor deposition apparatus, a sputtering apparatus, or the like, having a connection means with a cylinder and a gas flow rate adjustment means (or connected thereto). An inert gas such as argon gas (Ar gas), nitrogen gas, or other rare gas is introduced into the vacuum chamber 12 in order to form a phosphor layer by vacuum deposition in the medium vacuum. This inert gas is a gas that does not react with the substrate S and the phosphor layer during vacuum deposition.
An inert gas is introduced into the vacuum chamber 12 through an opening (gas introduction port) 60 a of the gas introduction nozzle 60. The introduction gas nozzle 60 (opening 60a) is provided, for example, in the vicinity of the heating evaporation unit 16 and on the bottom surface 12a of the vacuum chamber 12, and the detailed installation position of the introduction gas nozzle 60 (opening 60a) will be described later. This will be described in detail.

  The substrate holding / conveying mechanism 14 holds the substrate S and conveys it in a straight line, and includes a driving means 22, a linear motor guide 24, and a substrate holding means 26 as schematically shown in FIG. The 2A is a schematic plan view showing the substrate holding and conveying means of the phosphor sheet manufacturing apparatus shown in FIG. 1, and FIG. 2B is the substrate holding and conveying means of the phosphor sheet manufacturing apparatus shown in FIG. It is a typical front view which shows a means, (c) is a typical side view which shows the board | substrate holding | maintenance conveyance means of the fluorescent substance sheet manufacturing apparatus shown in FIG.

The drive unit 22 moves (reciprocates) the substrate holding unit 26 in the substrate transfer direction (hereinafter referred to as the transfer direction) M of the substrate S, and extends in the transfer direction M of the substrate S and is rotated by the holding member 30. A well-known linear movement mechanism using a ball screw, which includes a ball shaft 32 including a screw shaft 32a that is freely supported, a nut portion 32b screwed to the screw shaft 32a, and a motor 34 that rotates the screw shaft 32a. It is.
In the present invention, the driving means is not limited to the one using the ball screw 32 and the motor 34, and is necessary such as a conveying means using a cylinder, a conveying means using a ring-shaped chain rotated by the motor and the motor. Various known linear movement (conveyance) means can be used as long as they have excellent heat resistance.

The linear motor guide 24 (hereinafter referred to as the LM guide 24) assists the linear conveyance of the substrate holding means 26 (that is, the substrate S) by the driving means 22, and the guide rail 24a and the guide rail 24a movably in the longitudinal direction. It is a well-known linear motor guide comprising an engaging member 24b that engages.
Two guide rails 24 a extend in the transport direction M of the substrate S, are spaced apart from each other at a target position with the screw shaft 32 a as an axis, and are both fixed to the ceiling surface of the vacuum chamber 12. On the other hand, a total of four engaging members 24b are fixed to the substrate holding means 26 (the upper surface of a base 36 to be described later) so as to be engaged with each guide rail 24a two by two.

  The substrate holding means 26 (hereinafter referred to as holding means 26) holds the substrate S and is moved linearly by the driving means 22 while being guided by the LM guide 24. A mechanism 38 and a heat insulating member 40 are included.

The base 36 is a rectangular flat plate member that is horizontal when the manufacturing apparatus 10 is properly installed.
The nut portion 32b of the ball screw 32 is fixed to the center of the upper surface of the substrate 36, and the LM guide 24 is positioned at a symmetrical position on the diagonal surface of the upper surface of the substrate 36 according to the interval between the two guide rails 24a. The engaging member 24b is fixed.

The holding mechanism 38 includes an attachment member 38 a and a holding member 38 b, and four holding mechanisms 38 are arranged at the corners of the base 36.
The attachment member 38a has a rectangular cross-sectional substantially C-shaped shape. The mounting member 38a has a C-shaped opening portion facing inward, and a part of the C-shaped ceiling surface is placed on the corner of the base 36 from the outside in the direction orthogonal to the transport direction M. Fixed to hang down. Therefore, the holding means 26 has a space larger than the area of the base 36 at the lower part of the base 36.

  The holding member 38b has a holding means for holding the substrate S at the lower end, and is suspended and fixed to the mounting member 38a. That is, the holding mechanism 38 that holds the substrate S is suspended from the base 36 near the corner.

In the present invention, the method for holding the substrate S by the holding member 38b is not particularly limited, and a known method for holding a plate-like object from the upper surface, such as a method using a jig or the like, a method using static electricity, or a method using adsorption. Various methods are available. Further, if possible depending on the deposition region of the phosphor layer on the substrate S, etc., holding means for holding the four corners of the substrate S from below, holding means for holding the four sides of the substrate S from below using a jig or the like. May be used.
Further, the lower end position of the holding member 38b, that is, the height at which the substrate S is held / conveyed by a method such as inserting a spacer between the mounting member 38a and the holding member 38b, providing an adjusting means using a screw, or providing a lifting / lowering means using a cylinder. The height may be adjustable.

As described above, the base 36 is linearly conveyed by the driving means 22. Accordingly, the substrate holding / conveying mechanism 14 linearly conveys the substrate S by holding, for example, the vicinity of the four corners of the substrate S by the holding mechanism 38 and conveying the holding unit 26 by the driving unit 22.
In the present invention, the phosphor layer is formed with good crystallinity and high uniformity of film thickness distribution by forming the phosphor layer by medium vacuum vacuum deposition by resistance heating while linearly transporting the substrate S in this way. The formation of is realized.

For example, the phosphor layer of the phosphor sheet that is supposed to read a radiation image by a line sensor is required to have a high film thickness distribution uniformity within ± 3%, preferably within ± 2%.
When the phosphor layer is formed by vacuum evaporation, the substrate is usually rotated to form a film in order to form a phosphor layer having a uniform film thickness over the entire surface. Here, when the substrate S is rotated, the velocity (linear velocity) of the substrate surface (deposition surface) varies in the radial direction.

For example, in the vapor deposition by electron beam heating, since the vapor deposition is performed at a high degree of vacuum, the substrate and the evaporation source (the heating evaporation portion of the film forming material = crucible) can be disposed sufficiently apart from each other. As a result, it is possible to uniformly expose the vapor to the entire surface of the substrate in a state where the vapor of the film forming material is sufficiently diffused, and this difference in the velocity of the substrate surface in the radial direction is not a big problem. In particular, high film thickness distribution uniformity can be ensured by rotating the substrate at a high speed.
When the substrate S is rotated and vacuum-deposited on the spot, the edge of the opening of each chimney 50a of the plurality of crucibles 50 of the heating evaporation unit 16 and the edge of the substrate S to be rotated are linearly connected. A region formed by tying together is a second region of the present invention.

Here, the phosphor layer made of the various storage phosphors preferably formed by the production method of the present invention, particularly the phosphor layer made of an alkali halide storage phosphor, particularly the phosphor made of CsBr: Eu. When forming a layer by vacuum deposition (film formation), the system is once evacuated to a high degree of vacuum, and then an inert gas such as Ar gas or nitrogen gas is introduced into the system while maintaining the evacuation. Then, it is preferable to form the phosphor layer with a medium vacuum degree of about 0.1 to 10 Pa, particularly about 0.5 to 3 Pa.
As a result, a phosphor layer having a good columnar crystal structure can be formed, and a phosphor sheet having excellent photostimulated emission characteristics and image sharpness can be produced.

The production apparatus 10 of the present invention basically forms a phosphor layer in such a medium vacuum, and introduces an inert gas into the vacuum chamber 12 from the gas introduction nozzle 60 (opening 60a). However, vacuum deposition is performed by resistance heating in a medium vacuum.
In this degree of vacuum deposition in a medium vacuum, in order to ensure that the evaporated film forming material reaches the substrate S, it is necessary to significantly shorten the distance between the evaporation source and the substrate S as compared with a normal case. . For this reason, the vapor of the evaporation source reaches the substrate S before being sufficiently diffused. Therefore, even if the evaporation sources are arranged linearly in the radial direction so as to uniformly face the entire surface of the rotating substrate, a difference occurs in the facing time with the evaporation source in the radial direction due to the difference in the linear velocity of the substrate surface. As a result, a difference occurs in the exposure amount of the steam in the radial direction, and this difference directly becomes a difference in film thickness.
That is, in the medium vacuum vacuum deposition performed by rotating the substrate, it is necessary to devise the arrangement of the evaporation source in the heating evaporation unit in order to uniformly expose the vapor to the entire surface of the substrate, for example, within ± 3% In order to realize a high film thickness distribution uniformity, it is very difficult to set the position of the evaporation source.

On the other hand, in the manufacturing apparatus 10 of the present invention, the phosphor layer is formed by vacuum deposition while the substrate S is conveyed linearly in this way, so that the moving speed on the surface of the substrate S (non-deposition surface) is increased over the entire surface. Can be made uniform.
Accordingly, the vapor of the film forming material can be uniformly exposed on the entire surface of the substrate S only by making the evaporation amount of the film forming material in the direction H perpendicular to the transport direction M uniform, and the position of the simple evaporation source Even with the setting, it is possible to form a phosphor layer with high uniformity of film thickness distribution. In addition, by carrying out film formation by performing reciprocal conveyance of linear conveyance, the dispersion state of europium (activator), which is a trace component, in the phosphor layer can also be suitably performed.

Next, the arrangement position of the gas introduction nozzle 60 in the manufacturing apparatus 10 of the present invention will be described.
In the manufacturing apparatus 10 of the present invention, a first area A ₁ (see FIG. 1A) formed by linearly connecting the opening 60a of the gas introduction nozzle 60 and the opening 18b of the diffuser 18a; A second region formed by linearly connecting the edge of the opening of each chimney 50a of the plurality of crucibles 50 of the heating evaporation section 16 and the edge of the entire range D in which the substrate S is reciprocated by linear conveyance. A gas introduction nozzle 60 is provided at a position where A ₂ (see FIGS. 1A and 1B) does not intersect. For this reason, the flow of Ar gas introduced from the gas introduction nozzle 60 does not cross the deposition field (second region A ₂ ) by the film forming material vapor. This suppresses the occurrence of pressure distribution in the vapor deposition field due to the film forming material vapor, and uniformly exposes the film forming material vapor to the substrate S also in the transport direction M and the arrangement direction H (see FIG. 3) orthogonal thereto. can do. In this manner, the vapor of the film forming material can be exposed uniformly over the entire surface of the substrate S also in the transport direction M and the arrangement direction H.

In the present invention, if the phosphor layer having a required film thickness can be formed, the linear transport of the substrate S during the film formation can be performed by either a single linear transport or a single reciprocation (reciprocal transport). Multiple times may be performed. Further, the substrate transport path may be a zigzag shape or a wavy path as long as it is generally linear.
In general, the greater the number of times of passage through the upper portion of the heat evaporation unit 16 is, the higher the film thickness distribution uniformity can be. Therefore, the phosphor layer is formed by reciprocating a plurality of times. preferable. Further, the number of reciprocations may be determined appropriately according to the target film thickness of the phosphor layer or the target film thickness distribution uniformity, and the final conveyance may be in one direction. The conveyance speed of the linear conveyance is not particularly limited, and may be appropriately determined according to the speed limit of the LM guide 24, the number of reciprocations, the target phosphor layer thickness, and the like.

In the holding means 26 that holds the substrate S, a heat insulating member 40 is disposed immediately below the base 36 on which the nut portion 32b of the ball screw 32 and the engaging member 24b of the LM guide 24 are fixed on the upper surface. Here, as described above, in the manufacturing apparatus 10 of the illustrated example, the lower part of the base 36 is fixed by fixing the holding member 38b in a state of hanging from the base 36 using the substantially C-shaped attachment member 38a. It has a larger space than the base 36. Using this, in the illustrated example, the area of the heat insulating member 40 is made larger than the area of the base 36, and the entire lower surface of the base 36 is covered with the heat insulating member 40 with a sufficient margin.
The heat-insulating member 40 covers the base 36 with respect to a heating evaporation unit 16 (evaporation source) to be described later, so that the engagement member 24b of the LM guide 24 and the nut portion of the ball screw 32 are generated by radiant heat from the heating evaporation unit 16 or the like. This prevents 32b from being heated.

  As is clear from the above explanation, it has an excellent crystal structure that can realize high photostimulable light emission characteristics and image sharpness, and excellent film thickness uniformity that enables high-accuracy radiation image reading by a line sensor. In order to manufacture the phosphor sheet, it is necessary to perform vacuum deposition in a medium vacuum by resistance heating while the substrate S is conveyed linearly.

  Here, as is well known, a ball is incorporated in the engaging member 24b of the LM guide 24 and the nut portion 32b of the ball screw 32 to enable smooth movement, and the ball can be smoothly rotated. In order to do so, a lubricant such as grease is injected. Further, in order to enable smooth driving without having a ball, a sliding material such as grease is usually injected into the sliding portions of the driving means and the conveying guide means.

The heat insulating member 40 is not particularly limited, and various members can be used as long as they can shield the radiant heat from the heating evaporation unit 16 and prevent the engagement member 24b and the nut portion 32b and the base 36 from being heated. Is available. As an example, a stainless plate, a steel plate, an aluminum plate, a molybdenum plate, etc. are illustrated. The fixing method may be appropriately determined according to the heat insulating member 40.
Further, if necessary, the cooling means for the heat-insulating member 40 may be provided by means such as flowing cold water through a pipe contacting the heat-insulating member 40 or by passing water through a plate (heat-insulating member 40).

As described above, in the illustrated example, as a preferable aspect, the heat insulating member 40 has a larger area than the base 36, and the base on which the engaging member 24 b of the LM guide 24 and the nut portion 32 b of the ball screw 32 are fixed. 36 is disposed so as to cover the entire lower surface of 36. However, the present invention is not limited to this. For example, only the region corresponding to the engaging member 24b of the LM guide 24, or further the region corresponding to the nut portion 32b of the ball screw 32, is applied to the heating evaporation unit 16. You may cover with a heat insulating member.
However, in order to more suitably prevent the engagement member 24b and the nut portion 32b from being heated, a member that can transfer heat to the heating evaporation unit 16 is possible as shown in the illustrated example. It is preferable to cover with the heat insulating member 40 as far as possible.

Below the vacuum chamber 12, a heating evaporation unit 16 is disposed.
The heating evaporation unit 16 is a part that evaporates cesium bromide and europium bromide, which are film forming materials, by resistance heating. By this heating evaporation unit 16, a vapor deposition field composed of vapors of cesium bromide and europium bromide (film deposition material vapor) is formed.

  As described above, as a preferred embodiment, the manufacturing apparatus 10 performs binary vacuum deposition in which cesium bromide as a phosphor component and europium bromide as an activator component are independently heated and evaporated. Is. Accordingly, the heating evaporation unit 16 includes a crucible (container) 50 serving as an evaporation source for cesium bromide (for phosphor) and a crucible (container) serving as an evaporation source for europium bromide (for activator). 52 is arranged.

Such crucibles 50 and 52 are formed of a refractory metal such as tantalum (Ta), molybdenum (Mo), tungsten (W), etc., as in the case of the resistance heating evaporation source crucible in vacuum vapor deposition, and electrodes (not shown). When it is energized, it generates heat and heats / melts the filled film forming material to evaporate it.
In the present invention, the resistance heating power source (heating control means) is not particularly limited, and various systems used in the resistance heating apparatus such as a thyristor system, a DC system, and a thermocouple feedback system can be used. . Further, the output upon resistance heating is not particularly limited, and may be set as appropriate according to the film forming material to be used, the resistance value of the crucible forming material, the heat generation amount, or the like.

In the stimulable phosphor, the activator and the phosphor are, for example, about 0.0005 / 1 to 0.01 / 1 in molar concentration ratio, and most of the phosphor layer is the phosphor.
For this reason, in the illustrated example, the large amount of cesium bromide (for phosphor) crucible 50 is a cylindrical (drum-type) crucible. This crucible 50 has a slit-like opening extending in the axial direction of the drum on the side surface of the drum, and a rectangular cylindrical chimney 50a having an upper and lower opening surface having the same shape as the opening coincides with this opening. It is provided as a steam discharge part.
On the other hand, a low consumption crucible 52 for europium bromide (activator) is a small crucible formed by closing the upper surface of a normal boat type crucible with a lid having a chimney 52a similar to the above. Used.
By using a crucible having such a slit-like chimney, when bumping occurs due to local heating or abnormal heating in the crucible, the film forming material unexpectedly jumps out of the crucible and adheres to the surroundings or the substrate S. It can prevent contamination. In particular, in medium vacuum vapor deposition using resistance heating, the substrate S and the vapor deposition source need to be arranged close to each other as described above, and thus the effect is great.

  Here, in the manufacturing apparatus 10, evaporation of the film forming material in the arrangement direction H is performed by arranging a plurality of crucibles 50 and 52 in a direction H (hereinafter referred to as arrangement direction H) orthogonal to the transfer direction M of the substrate S. The film forming material vapor is uniformly supplied to the entire surface of the substrate S that is linearly conveyed by making the amount uniform, and, for example, a phosphor layer having a film thickness distribution uniformity of ± 3% or less is formed. Note that the crucibles are insulated from each other by being separated or by inserting an insulating material.

As shown in FIG. 3, which is a schematic plan view of the heating evaporation unit 16, in the illustrated example, as an example, the crucible 50 for cesium bromide matches the axial direction of the cylinder (drum) with the arrangement direction H. , 6 are arranged. In the crucible 50, the electrodes are formed on the end face of the cylinder, and each crucible 50 is independently connected to a power source. Corresponding to each crucible 50, a crystal oscillator sensor 54 for measuring the evaporation amount of cesium bromide is arranged (in FIGS. 1A and 1B, the overall configuration of the apparatus is clarified). The amount of current supplied to the crucible 50 is controlled in accordance with the measurement result of the evaporation amount. Note that the evaporation amount may be controlled by a temperature sensor.
On the other hand, six crucibles 52 for europium bromide, which are boat-type crucibles, are arranged such that the longitudinal direction coincides with the arrangement direction H. The crucible 52 also has electrodes formed at both ends in the arrangement direction H, and is connected to independent power sources.

Here, in the present invention, the edge of the opening of each chimney 50a of the plurality of crucibles 50 of the heating evaporation section 16 and the entire range D (see FIG. 1 (a)) in which the substrate S is reciprocally conveyed by linear conveyance. The second region A2 formed by linearly connecting the edge portion is used as an evaporation field by the raw material vapor (cesium bromide and europium bromide vapor) formed by the heating evaporation unit 16, and this _second field A2 in the region a _2, it is assumed that the phosphor layer is formed on the substrate S. Therefore, when forming the phosphor layer, in order to uniformly grow the columnar crystals constituting the phosphor layer, in order to eliminate the pressure distribution in the second region A ₂ (evaporation field), It is necessary to suppress disturbance such as pressure fluctuation caused by the flow. In order to reduce this disturbance, in the present invention, the first region A ₁ formed by linearly connecting the edge of the opening 60a of the gas introduction nozzle 60 and the edge of the opening 18b of the diffuser 18a. And the gas introduction nozzle 60 is provided at a position where the second region A ₂ (evaporation field) does not intersect.

In the illustrated example, as a preferred embodiment, one crucible 50 and a crucible 52 are paired, that is, one evaporation source of cesium bromide that is a film forming material of a phosphor and an odor that is a film forming material of an activator. A pair of evaporation sources of europium fluoride are arranged so that they are aligned in the linear conveyance direction M of the substrate S, and more preferably, they are arranged as close as possible in terms of the configuration of the apparatus and the crucible. is doing.
By adopting such a structure, europium bromide vapor is sufficiently dispersed in the base cesium bromide vapor, and a slight amount of europium (activator) is uniformly dispersed in the phosphor layer. Thus, a phosphor layer having excellent photostimulable light emission characteristics and the like can be formed.

Further, in the row of crucibles 50 and the row of crucibles 52, the crucibles to be arranged are arranged as close to the arrangement direction H as possible in the arrangement of the apparatus and the crucible, and the row of crucibles is the substrate S. It is preferable that the length sufficiently includes the size in the arrangement direction H.
By adopting such a configuration, it is possible to make the evaporation vapor amount of the film forming material in the arrangement direction H uniform, and to form a phosphor layer with higher film thickness distribution uniformity.

The number of crucible rows in the arrangement direction H may be one, may be two as in the illustrated example, and may be three or more.
Here, in the case of having a plurality of crucible rows, each crucible row, when viewed from the transport direction M of the substrate S, discharges the film-forming material vapors of the other crucible rows (the slit shape). It is preferable to arrange so that the gaps in the arrangement direction H of the chimneys) are filled with each other, and it is more preferable to arrange the film formation material vapor discharge ports so as not to overlap the conveyance direction M in different rows. In other words, when viewed from the transfer direction M, it is preferable that the film-forming material vapor discharge ports be staggered in each crucible row. In the illustrated example, in each of the two crucible rows in the arrangement direction H, when viewed from the transport direction M, each of the crucible rows is positioned so that the steam outlets of the other crucible row are located A row of crucibles is arranged.
By adopting such a configuration, it is possible to make the evaporation vapor amount of the film forming material in the arrangement direction H uniform, and to form a phosphor layer with higher film thickness distribution uniformity.

Further, when a plurality of crucible rows in the arrangement direction H are provided, it is preferable that the row of crucibles 50 for cesium bromide (activator) having a large evaporation amount be positioned outside the transport direction M.
With such a configuration, the evaporation amount sensor of cesium bromide having a large evaporation amount can be arranged in an open space outside the crucible row with respect to the transport direction M, that is, the evaporation amount sensor. The degree of freedom of selection and the degree of freedom of design of the manufacturing apparatus 10 can be improved.

  In addition, although illustration is abbreviate | omitted, the heating-evaporation part 16 of the manufacturing apparatus 10 arrange | positions the square cylinder-shaped heat insulation board higher than the uppermost part of a crucible which surrounds all the crucibles in four horizontal directions, and this heat insulation board. A shutter for shielding the film forming material vapor is disposed so that the upper open surface of the film can be closed / opened freely.

In the manufacturing apparatus 10 of this embodiment, the gas injection nozzle 60, the first area A _1, by providing the second region A _{2 (evaporation} field) and does not intersect position, when the phosphor layer formation, The flow of Ar gas from the gas introduction nozzle 60 does not cross the vapor deposition field (second region A ₂ ) by the film forming material vapor. For this reason, disturbance to the _second region A2 is reduced, variation in the gas pressure in the vapor deposition field due to the film forming material vapor is reduced, and the film forming material vapor is uniformly distributed in the transport direction M and the arrangement direction H. Can be exposed to S. As a result, a uniform columnar crystal can be grown on the surface of the substrate S, the film thickness distribution uniformity is high, and there is a high phosphor layer that has excellent crystallinity and excellent image sharpness and image sharpness. A phosphor sheet having no image quality unevenness can be obtained.

  Next, a method for forming a phosphor layer on the substrate S by the manufacturing apparatus 10 (a method for manufacturing a phosphor sheet) will be described.

  First, the vacuum chamber 12 is opened, the substrate S is held on the holding member 38b of the holding means 26, and all the crucibles 50 are filled with cesium bromide and all the crucibles 52 are filled with europium bromide to a predetermined amount. The shutter is closed, and the vacuum chamber 12 is further closed.

Next, the vacuum pump 18 is driven to evacuate the inside of the vacuum chamber 12. When the inside of the vacuum chamber 12 reaches 8 × 10 ⁻⁴ Pa, for example, the gas introduction nozzle 60 opens the opening while continuing the evacuation. For example, Ar gas is introduced into the vacuum chamber 12 through 60a, and the pressure in the vacuum chamber 12 is adjusted to, for example, 1.0 Pa. Further, the resistance heating power source is driven and all the crucibles 50 are driven. The crucible 52 is energized to heat the film forming material.
Thereafter, when a predetermined time set in advance has elapsed, the shutter is opened, and then the motor 34 is driven to start linear conveyance of the substrate S at a predetermined speed to form a phosphor layer on the surface of the substrate S. To start.

  When the reciprocation of the predetermined number of times of linear conveyance set according to the thickness of the phosphor layer to be formed is completed, the linear conveyance of the substrate S is stopped, the shutter is closed, the resistance heating power is turned off, and the gas The amount of Ar gas introduced by the introduction nozzle 60 is increased to bring the inside of the vacuum chamber 12 to atmospheric pressure, and then the vacuum chamber is opened to take out the substrate S on which the phosphor layer is formed, that is, the produced phosphor sheet.

Incidentally, the phosphor sheet is, the crucible 50 and 52 were arranged in the conveyance orthogonal direction, and Ar gas from the gas introduction nozzle 60 provided in the first region A ₁ and the second region A ₂ and does not cross the position Further, the phosphor layer is formed by medium vacuum vacuum deposition by resistance heating while the substrate S is conveyed linearly. Thus, in this embodiment, the flow of Ar gas from the gas introduction nozzle 60 does not cross the vapor deposition field (second region A ₂ ) by the film forming material vapor. For this reason, disturbance to the _second region A2 is reduced, variation in the gas pressure in the vapor deposition field due to the film forming material vapor is reduced, and the film forming material vapor is uniformly distributed in the transport direction M and the arrangement direction H. Can be exposed to S. As a result, a uniform columnar crystal can be grown on the surface of the substrate S, the film thickness distribution uniformity is high, and there is a high phosphor layer that has excellent crystallinity and excellent image sharpness and image sharpness. A phosphor sheet having no image quality unevenness can be obtained.

Next, a second embodiment of the present invention will be described.
FIG. 4 is a plan view showing the main part of the phosphor sheet manufacturing apparatus according to the second embodiment of the present invention. FIG. 4 corresponds to FIG. 3 in the phosphor sheet manufacturing apparatus of the first embodiment.
In the present embodiment, the same components as those in the phosphor sheet manufacturing apparatus of the first embodiment shown in FIGS. 1A and 1B to FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted. To do.

As shown in FIG. 4, the phosphor sheet manufacturing apparatus 10a of the present embodiment has two gas introduction nozzles 60 and 62 as compared with the phosphor sheet manufacturing apparatus 10 (see FIG. 3) of the first embodiment. The other configuration is the same as that of the phosphor sheet manufacturing apparatus 10 of the first embodiment, and the detailed description thereof is omitted.
In this embodiment, a gas introduction nozzle 62 is further provided in addition to the gas introduction nozzle 60 of the first embodiment.
The gas introduction nozzle 62 is provided at a position that satisfies the conditions of the arrangement position of the gas introduction nozzle 60 of the first embodiment. In the present embodiment, the gas introduction nozzle 62 is provided on the bottom surface 12 a of the vacuum chamber 12 on the side closer to the exhaust port 18 b than the gas introduction nozzle 60.

It goes without saying that the same effect as that of the first embodiment can be obtained also in this embodiment. In the present embodiment, the first region A ₁ and the third region A ₃ formed by linearly connecting the edge of the opening 62a of the gas introduction nozzle 62 and the edge of the opening 18b of the diffuser 18a. since none of the (FIGS. 1 (a) and FIG. 4) is, the gas introduction nozzle 60, 62 is provided in a position that does not intersect with the second region _{a 2,} Ar from the gas introduction nozzle 60 and 62 The gas flow does not cross the deposition field (second region A ₂ ) by the film forming material vapor. For this reason, disturbance to the _second region A2 is reduced, variation in the gas pressure in the vapor deposition field due to the film forming material vapor is reduced, and the film forming material vapor is uniformly distributed in the transport direction M and the arrangement direction H. Can be exposed to S. As a result, a uniform columnar crystal can be grown on the surface of the substrate S, the film thickness distribution uniformity is high, and there is a high phosphor layer that has excellent crystallinity and excellent image sharpness and image sharpness. A phosphor sheet having no image quality unevenness can be obtained.

Further, in this embodiment, when a plurality of gas introduction nozzles (openings) are provided, the amount of gas introduction from each gas introduction nozzle 60, 62 is adjusted to eliminate pressure variation in the vacuum chamber 12, and to form a film. It is possible to eliminate variations in the pressure of the vapor deposition field due to the material vapor.
Further, in the present embodiment, when a plurality of gas introduction nozzles (openings) are provided, the gas introduction nozzle farther from the exhaust port is used as the gas introduction amount from the gas introduction nozzle (opening) closer to the exhaust port. It is preferable that the number be larger than (opening). For example, the gas introduction amount from the gas introduction nozzle 62 (opening 62a) is set to 1.5 times the gas introduction amount of the gas introduction nozzle 60 (opening 60a).

In this embodiment, two gas introduction nozzles 60 and 62 are provided. However, the present invention is not limited to this, and two or more gas introduction nozzles may be provided. Even in this case, it is preferable that the gas introduction amount from the gas introduction nozzle on the exhaust port 18b side is large.
Furthermore, in this embodiment, a plurality of vacuum gauges (measuring means) for measuring the degree of vacuum in the vacuum chamber 12 are provided, and gas introduction from each gas introduction nozzle is performed so that the pressure in the vacuum chamber 12 becomes a set pressure. The amount may be adjusted. Thus, it is possible to reduce the variation in pressure in the vacuum chamber 12, can be further disturbance can the reduced in the second region A _2, to obtain a further phosphor sheet is not uneven image quality in high quality.

Next, a third embodiment of the present invention will be described.
FIG. 5A is a schematic plan view showing a phosphor sheet manufacturing apparatus according to the third embodiment of the present invention, and FIG. 5B is a partial cross-sectional view of the main part of FIG. FIG. 5 (a) corresponds to FIG. 3 in the phosphor sheet manufacturing apparatus of the first embodiment.
In the present embodiment, the same components as those in the phosphor sheet manufacturing apparatus of the first embodiment shown in FIGS. 1A and 1B to FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted. To do.

As shown in FIG. 5, the phosphor sheet manufacturing apparatus 10 b of the present embodiment has an opening 60 a of the gas introduction nozzle 60 as compared with the phosphor sheet manufacturing apparatus 10 (see FIG. 3) of the first embodiment. Since the diffuser plate 70 is provided above, and the other configuration is the same as that of the phosphor sheet manufacturing apparatus 10 of the first embodiment, detailed description thereof is omitted.
The diffusion plate 70 of this embodiment diffuses an inert gas introduced into the vacuum chamber 12 from the gas introduction nozzle 60.
The diffusion plate 70 suppresses generation of a flow that causes a disturbance in the vapor deposition field (second region A ₂ ) by the film forming material vapor obtained by the heating evaporation unit 16. Thereby, the same effect as the first embodiment can be obtained. Therefore, as in the first embodiment, the positions where the gas introduction nozzles 60 are provided are the first area A ₁ (see FIG. 1A) and the second area A ₂ (see FIG. 1A). It is not limited to the position where does not intersect.

However, first an area A ₁ as in the first embodiment, by providing the gas injection nozzle 60 in the second region A ₂ and does not cross position, the film forming material vapor obtained by heating the evaporation section 16 It is possible to further suppress the generation of a flow causing a disturbance in the vapor deposition field (second region A ₂ ). Thereby, the disturbance in _2nd area | region A2 can further be reduced, and the fluorescent substance sheet which is still high quality and does not have image quality nonuniformity can be obtained.

Also in this embodiment, two or more gas introduction nozzles may be provided as in the second embodiment. In this case, the diffusion plate is provided so as to cover the openings of all the gas introduction nozzles. Incidentally, even in the case where the plurality gas injection nozzle, necessarily is not necessary to provide a gas injection nozzle to a position where the first region A ₁ and does not intersect the second region A ₂ and are of course.

  Furthermore, in this embodiment, a plate in which a plurality of holes 74 are formed may be used as the diffusion plate 72. The flow of the inert gas can be rectified by the holes 74 formed in the diffusion plate 72. In addition, the pressure distribution of the inert gas flowing through the diffusion plate 72 can be adjusted by changing the size and formation position of the hole 74 of the diffusion plate 72. Thus, it goes without saying that the same effect as in the first embodiment can also be obtained by using the diffusion plate 72 in which the holes 74 are formed, as in the third embodiment.

  In any of the above-described embodiments, the phosphor sheet body manufacturing apparatus that forms the phosphor layer by linearly transporting the substrate in the transport direction has been described, but the present invention is not limited to this, and the substrate is not limited to this. There are no particular restrictions on the method of transporting the substrate, such as a method of forming the phosphor layer while holding it, or a method of forming the phosphor layer while rotating the substrate.

  As mentioned above, although the phosphor sheet manufacturing apparatus of this invention was demonstrated in detail, this invention is not limited to the said Example, You may perform various improvement and change in the range which does not deviate from the summary of this invention. Of course.

Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention. Needless to say, the present invention is not limited to the following examples.
In this example, phosphor sheets were produced using the phosphor sheet manufacturing apparatuses of Examples 1 to 3 and Comparative Example 1 shown in FIGS. 7A to 7D, and these phosphor sheets were used. Image unevenness was evaluated.
In addition, the structure of the fluorescent substance sheet by the fluorescent substance sheet manufacturing apparatus of Example 1-Example 3 and Comparative Example 1 was set as the structure by which the fluorescent substance layer was provided in the board | substrate. An aluminum substrate was used as the substrate. This aluminum substrate has a purity of 95% by mass, and the size of the substrate is 200 mm × 200 mm.

Next, the phosphor sheet manufacturing apparatus of Examples 1 to 3 and Comparative Example 1 will be described.
The phosphor sheet manufacturing apparatuses 80, 82, and 84 of Examples 1 to 3 shown in FIGS. 7A to 7C are the phosphor sheet manufacturing apparatuses 10 of the first to third examples, respectively. The same materials as 10a and 10b were used. For this reason, the same code | symbol is attached | subjected to the same structure as the fluorescent substance sheet manufacturing apparatus 10, 10a, 10b of 1st Example-3rd Example, and the detailed description is abbreviate | omitted.
The phosphor sheet manufacturing apparatus 80 of Example 1 shown in FIG. 7A has the same configuration as the phosphor sheet manufacturing apparatus 10 of the first example, and detailed description thereof is omitted.
Moreover, the phosphor sheet manufacturing apparatus 82 of Example 2 shown in FIG.7 (b) is the structure similar to the phosphor sheet manufacturing apparatus 10a of 2nd Example, The detailed description is abbreviate | omitted.
Furthermore, the phosphor sheet manufacturing apparatus 84 of Example 3 shown in FIG. 7C has the same configuration as the phosphor sheet manufacturing apparatus 10b of the third example, and a detailed description thereof is omitted.

  In addition, the phosphor sheet manufacturing apparatus 100 of Comparative Example 1 shown in FIG. 7D is different from the phosphor sheet manufacturing apparatus 80 of Example 1 in the arrangement position of the gas introduction nozzle 102. The configuration other than that is the same as that of the phosphor sheet manufacturing apparatus 80 of Example 1. In the phosphor sheet manufacturing apparatus 100 of Comparative Example 1, the gas introduction nozzle 102 is provided at a position facing the vacuum pump 18 with the heating evaporation unit 16 sandwiched between the bottom 12a of the vacuum chamber 12 and the heating evaporation unit 16. In the phosphor sheet manufacturing apparatus 100 of Comparative Example 1, the flow of Ar gas supplied into the vacuum chamber 12 crosses the vapor deposition field formed by the heating evaporation unit 16.

Further, in the phosphor sheet manufacturing apparatuses 80, 82, 84, and 100 of Examples 1 to 3 and Comparative Example 1 shown in FIGS. 7A to 7D, the inside of the vacuum chamber 12 is formed when the phosphor layer is formed. The pressure (unit: Pa) at each of the measurement positions P ₁ , P ₂ , and P ₃ was measured. Measuring position P ₁ is a position opposed to the vacuum pump 18 across the thermal evaporating section 16, the measurement position P ₂ is between thermal evaporating section 16 and the vacuum pump 18, the measurement position P _3, the heating It is between the inner wall of the vacuum chamber 12 on the arrangement direction side of the evaporation section 16. The pressure measurement results are shown in Table 1 below. Incidentally, the unit of pressure in Table each measurement position _P 1 shown in _1, P 2, _{P 3} is Pa (Pascal).
In the phosphor sheet manufacturing apparatuses 80, 82, 84, and 100 of Examples 1 to 3 and Comparative Example 1, the distance between the substrate S and the heating evaporation unit 16 is 15 cm, and the substrate S is conveyed linearly. A phosphor layer was formed.

  Next, the phosphor sheet manufacturing method by the phosphor sheet manufacturing apparatus of Examples 1 to 3 and Comparative Example 1 will be described. The phosphor sheet manufacturing method by the phosphor sheet manufacturing apparatus of Examples 1 to 3 and Comparative Example 1 is different only in that the number or arrangement position of the gas inlets is different, or that a diffusion plate is provided. Other methods are the same. For this reason, below, the phosphor sheet manufacturing method by the phosphor sheet manufacturing apparatus of Examples 1 to 3 and Comparative Example 1 will be described together.

In this example, a cesium bromide (CsBr) powder having a purity of 4N or more and a molten product of europium bromide (EuBr ₂ ) having a purity of 3N or more were prepared as an evaporation source. The EuBr ₂ melt was prepared by putting powder in a platinum crucible in a tube furnace having a sufficient halogen atmosphere to prevent oxidation, heating to 800 ° C. to melt, cooling, and taking out from the furnace. As a result of analyzing trace elements in each raw material by ICP-MS method (inductively coupled high-frequency plasma spectroscopy-mass spectrometry), alkali metals (Li, Na, K, Rb) other than Cs in CsBr are each 10 ppm by mass. The other elements such as alkaline earth metals (Mg, Ca, Sr, Ba) were 2 mass ppm or less. Moreover, rare earth elements other than Eu in EuBr ₂ were each 20 ppm by mass or less, and other elements were 10 ppm by mass or less. Since these raw materials have high hygroscopicity, they are stored in a desiccator that maintains a dry atmosphere with a dew point of −20 ° C. or less, and are taken out immediately before use.

In forming the phosphor layer, first, the substrate was placed on a substrate holder in a vacuum deposition apparatus.
After filling the crucible container for resistance heating in the apparatus with the CsBr evaporation source and the EuBr ₂ evaporation source, the main exhaust valve was opened to exhaust the interior of the apparatus to a vacuum degree of 1 × 10 ⁻³ Pa.
At this time, a combination of a rotary pump, a mechanical booster, and a diffusion pump was used as the vacuum exhaust device. Furthermore, a cryopump for exhausting moisture was used to remove moisture. Thereafter, the exhaust is switched from the main exhaust valve to the bypass, Ar gas is introduced into the apparatus, the degree of vacuum is 0.5 Pa, Ar plasma is generated by the plasma generator (ion gun), and the surface of the oxide layer is Washing was performed.

Thereafter, the exhaust was switched to the main exhaust valve and exhausted to a vacuum of 1 × 10 ⁻³ Pa, and then the exhaust was switched to bypass again, and a predetermined amount of Ar gas was introduced to obtain a vacuum of 1.0 Pa.
In the phosphor sheet manufacturing apparatus 82 of Example 2, the gas introduction amount of the gas introduction nozzle 62 was 1.5 times the gas introduction amount of the gas introduction nozzle 60.

After each of the evaporation sources (CsBr) and EuBr ₂ ) is heated and melted with a resistance heating device with the shutter provided between the substrate S and the heating evaporation unit 16 (the crucible 50 and the crucible 52) closed, Only the shutter on the crucible 50 side was opened, and the CsBr phosphor matrix was deposited on the surface of the substrate S.
Next, 3 minutes after opening the shutter, the shutter on the crucible 52 side was also opened, and a CsBr: Eu stimulable phosphor was deposited on the CsBr phosphor matrix.
At this time, in order to make the thickness of the phosphor layer to be formed uniform, the substrate S was periodically linearly conveyed at a conveyance speed of 200 mm / second.

  The deposition rate was 8 μm / min. Further, the resistance current of each resistance heating device of the heating evaporation unit 16 was adjusted to control the Eu / Cs molar concentration ratio in the stimulable phosphor layer to be 0.001 / 1. After vapor deposition, the inside of the apparatus was brought to atmospheric pressure, and the substrate was taken out from the apparatus. Next, the substrate was placed in a heat treatment furnace, the inside of the heat treatment furnace was placed in a nitrogen gas atmosphere, and heat treatment was performed at a temperature of 200 ° C. for 2 hours.

  As a result, a phosphor layer having a densely forested structure with columnar crystals of the phosphor extending in a substantially vertical direction was formed on the surface of the substrate. The thickness of the phosphor layer was 600 μm, and the area where the phosphor layer was formed was 200 mm × 200 mm. In this way, a phosphor sheet comprising the substrate and the phosphor layer was produced by co-evaporation.

  Here, FIG. 8 is an SEM image showing the phosphor layer of the phosphor sheet produced by the phosphor sheet manufacturing apparatus of Example 1, and (a) shows the phosphor layer on the vacuum pump side of the substrate. (B) shows the phosphor layer on the opposite side of the substrate from the vacuum pump. FIG. 9 is an SEM image showing the phosphor layer of the phosphor sheet produced by the phosphor sheet manufacturing apparatus of Comparative Example 1, and (a) shows the phosphor layer on the vacuum pump side of the substrate. (B) shows the phosphor layer on the opposite side of the vacuum pump of the substrate. 8A corresponds to FIG. 9A, and FIG. 8B corresponds to FIG. 9B. In addition, the imaging magnification in each SEM image shown to FIG. 8 (a) and (b) and FIG. 9 (a) and (b) is 1000 times.

As shown in FIGS. 8A and 8B, in the phosphor layer produced by the phosphor sheet manufacturing apparatus of Example 1, all the formed columnar crystals are aligned in the substrate plane, and in the substrate plane. The uniformity was high.
On the other hand, the phosphor layer produced by the phosphor sheet manufacturing apparatus of Comparative Example 1 has the columnar crystals of the phosphor layer on the vacuum pump 18 side shown in FIG. 9 (a), but the vacuum pump 18 shown in FIG. 9 (b). The columnar crystal on the opposite side of the growth was disordered. Thus, the phosphor layer produced by the phosphor sheet manufacturing apparatus of Comparative Example 1 had a low uniformity in the substrate plane.

Next, in this example, image quality unevenness was evaluated for each phosphor sheet produced. A method for evaluating the image quality unevenness will be described.
First, a tungsten tube is used on the surface of each phosphor sheet produced, and X-ray with a tube voltage of 80 kVp is irradiated at a dose of 10 mR (2.58 × 10 ⁻⁶ C / kg), and then a semiconductor with a wavelength of 660 nm. Each phosphor sheet is irradiated with laser light with an excitation energy of 5 J / m ² , and the photostimulated light emitted from the surface of each phosphor sheet is received by a light receiver (photomultiplier tube with spectral sensitivity S-5). did. The received light is converted into an electrical signal. Based on this, the electrical signal is converted into a digital signal, a solid image is obtained by an image reproducing device configured as an image, and the read image is visualized on a film by a laser printer. Output.

  Next, the visible image recorded on the film was visually evaluated for each phosphor sheet. Regarding the evaluation, “◎” indicates that there is no image quality unevenness, “○” indicates that there is no image quality unevenness, and “△” indicates that there is some image quality unevenness. "X" was used. Each phosphor sheet was evaluated based on such criteria. These results are shown in Table 1 below.

As shown in Table 1 above, image quality unevenness was not observed in the phosphor layers produced by the phosphor sheet manufacturing apparatuses of Examples 1 to 3. Further, the phosphor layer produced by the phosphor sheet manufacturing apparatus of Example 1 had a high in-plane uniformity of columnar crystals as shown in FIGS. 8 (a) and 8 (b). From the evaluation results of the image quality unevenness, it is clear that the phosphor layers by the phosphor sheet manufacturing apparatuses of Example 2 and Example 3 also have high in-plane uniformity of columnar crystals.
On the other hand, image quality unevenness was observed in the phosphor layer produced by the phosphor sheet manufacturing apparatus of Comparative Example 1.

(A) is typical sectional drawing which shows the fluorescent substance sheet manufacturing apparatus which concerns on the 1st Example of this invention, (b) is a typical side of the fluorescent substance sheet manufacturing apparatus shown to Fig.1 (a). It is sectional drawing. (A) is a typical top view which shows the board | substrate holding | maintenance conveyance means of the fluorescent substance sheet manufacturing apparatus shown in FIG. 1, (b) is a schematic diagram which shows the board | substrate holding | maintenance conveyance means of the fluorescent substance sheet manufacturing apparatus shown in FIG. It is a typical front view, (c) is a typical side view which shows the board | substrate holding | maintenance conveyance means of the fluorescent substance sheet manufacturing apparatus shown in FIG. It is a schematic plan view which shows the heating evaporation part of the fluorescent substance sheet manufacturing apparatus shown in FIG. It is a typical top view which shows the fluorescent substance sheet manufacturing apparatus which concerns on the 2nd Example of this invention. (A) is a typical top view which shows the fluorescent substance sheet manufacturing apparatus based on the 3rd Example of this invention, (b) is principal part fragmentary sectional drawing of Fig.5 (a). (A) is a typical top view which shows the modification of the diffusion plate in the fluorescent substance sheet manufacturing apparatus based on the 3rd Example of this invention, (b) is arrangement | positioning of the diffusion plate of Fig.6 (a) FIG. (A) is a typical perspective view which shows the phosphor sheet manufacturing apparatus of Example 1, (b) is a typical perspective view which shows the phosphor sheet manufacturing apparatus of Example 2, (c) is FIG. 5 is a schematic perspective view showing the phosphor sheet manufacturing apparatus of Example 3, and (d) is a schematic perspective view showing the phosphor sheet manufacturing apparatus of Comparative Example 1. It is a SEM image which shows the fluorescent substance layer of the fluorescent substance sheet produced with the fluorescent substance sheet manufacturing apparatus of Example 1, (a) shows the fluorescent substance layer by the side of the vacuum pump of a board | substrate, (b) These show the fluorescent substance layer of the other side of the vacuum pump of a board | substrate. It is a SEM image which shows the fluorescent substance layer of the fluorescent substance sheet produced with the fluorescent substance sheet manufacturing apparatus of the comparative example 1, (a) shows the fluorescent substance layer by the side of the vacuum pump of a board | substrate, (b) These show the fluorescent substance layer of the other side of the vacuum pump of a board | substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10a, 10b, 100 Phosphor sheet manufacturing apparatus 12 Vacuum chamber 12a Bottom surface 12b Side surface 14 Substrate holding conveyance means 16 Heating evaporation part 18 Vacuum pump 20 RF matching box 22 Driving means 24 LM guide 24a Guide rail 24b Engaging member 26 (Substrate) Holding means 30 Holding member 32 Ball screw 32a Screw shaft 32b Nut portion 34 Motor 36 Base 38 Holding mechanism 38a Mounting member 38b Holding member 40 Thermal insulation member 50, 52 Crucible 60, 62, 80 Gas introduction nozzle 70, 72 Diffuser plate 74 holes S substrate

Claims (11)

A phosphor sheet manufacturing apparatus for forming a stimulable phosphor layer by vacuum deposition on the surface of a sheet-like substrate,
A vacuum chamber;
A vacuum exhaust means for exhausting the inside of the vacuum chamber through an exhaust port provided on a side surface of the vacuum chamber;
Resistance heating means for heating the film-forming material of the stimulable phosphor layer housed in a container by resistance heating, and releasing the vapor of the film-forming material from the opening of the container;
A substrate holding means for holding the substrate above the resistance heating means;
A gas introduction means for introducing an inert gas into the vacuum chamber through at least one gas introduction port in order to adjust the degree of vacuum in the vacuum chamber during the formation of the phosphor layer; ,
A first region formed by linearly connecting an edge of the gas inlet and an edge of the exhaust; an edge of the opening of the container of the resistance heating means; and an edge of the substrate The phosphor sheet manufacturing apparatus is characterized in that the gas introduction port is provided so as not to intersect a second region formed by linearly connecting the two. A phosphor sheet manufacturing apparatus for forming a stimulable phosphor layer by vacuum deposition on the surface of a sheet-like substrate,
A vacuum chamber;
A vacuum exhaust means for exhausting the inside of the vacuum chamber through an exhaust port provided on a side surface of the vacuum chamber;
Resistance heating means for heating the film-forming material of the stimulable phosphor layer housed in a container by resistance heating, and releasing the vapor of the film-forming material from the opening of the container;
A substrate holding means for holding the substrate above the resistance heating means;
A gas introduction means for introducing an inert gas into the vacuum chamber through at least one gas introduction port in order to adjust the degree of vacuum in the vacuum chamber during the formation of the phosphor layer;
A phosphor sheet manufacturing apparatus, comprising: a diffusion plate that is provided above the gas inlet and diffuses the inert gas.   A first region formed by linearly connecting an edge of the gas inlet and an edge of the exhaust; an edge of the opening of the container of the resistance heating means; and an edge of the substrate The phosphor sheet manufacturing apparatus according to claim 2, wherein the gas introduction port is provided so as not to intersect a second region formed by linearly connecting the two.   When there are a plurality of the gas inlets, the gas inlet means adjusts the amount of gas introduced from each gas inlet so that the vapor pressure of the film forming material obtained by the resistance heating means is constant. The phosphor sheet manufacturing apparatus according to claim 1, wherein the storage phosphor layer is formed.   When there are a plurality of the gas inlets, the stimulable phosphor layer is formed by increasing the gas introduction amount of the gas inlet closer to the exhaust port than the gas introduction amount of the gas inlet farther from the exhaust port. The phosphor sheet manufacturing apparatus according to any one of claims 1 to 4, wherein the film is formed.   The phosphor sheet manufacturing apparatus according to claim 1, further comprising a diffusion plate provided above the gas introduction port and diffusing the inert gas.   The phosphor sheet manufacturing apparatus according to claim 2, wherein the diffusion plate is formed with a plurality of holes.   The phosphor sheet manufacturing apparatus according to claim 7, wherein the plurality of holes provided in the diffusion plate include those having different diameters.   Furthermore, it has at least one measuring means for measuring the degree of vacuum in the vacuum chamber, and the amount of gas introduced from each gas inlet by the gas introducing means based on the degree of vacuum measured by each measuring means The phosphor sheet manufacturing apparatus according to claim 4, wherein the storage phosphor layer is formed by adjusting   Furthermore, the fluorescent substance sheet manufacturing apparatus of Claim 1-9 which has a board | substrate conveyance means which conveys the said board | substrate with a board | substrate holding means with a linear conveyance path | route.   The said sheet | seat in the said resistance heating means is a fluorescent substance sheet manufacturing apparatus of Claims 1-10 arranged in multiple numbers in the direction orthogonal to the board | substrate conveyance direction by the said board | substrate conveyance means.

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