JP2003075543A - Radiation conversion sheet, radiation imaging device and manufacturing method thereof, and radiation imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an interlayer peeling of phosphor layer within a radiation conversion sheet. SOLUTION: This radiation conversion sheet is provided with a support base having at least a conductive material layer 1 and a resin layer 2, and a phosphor layer 3 formed on the surface of the resin layer 2 of the support base. This radiation conversion sheet is provided with a support base having at least a first resin layer, a conductive material layer and a second resin layer, and a phosphor layer formed on the surface of the second resin layer. This radiation conversion sheet is provided with a support base for supporting at least a first resin layer, a conductive material layer, and a second resin layer and a phosphor layer formed on the surface of the resin layer, wherein the adhesion of the interface between the first resin layer and the conductive material layer being smaller than the adhesion of the interface between the second resin layer and the conductive material layer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a radiation conversion sheet,
The present invention relates to a radiation imaging apparatus and a method of manufacturing the same, and a radiation imaging system, and more particularly, to a radiation conversion sheet that converts incident radiation into light by a phosphor and emits the light, a radiation imaging apparatus and a method of manufacturing the same, and a radiation imaging system.

[0002]

2. Description of the Related Art In X-ray diagnosis for X-ray examination of a human body, the X-ray photography method using a screen-film system using a combination of a screen and film has been used conventionally. As a result, an X-ray imaging apparatus by digital radiography using a fluorescent plate and a photoelectric conversion imaging element, which is a new radiographic method, has been developed and commercialized. As a radiation conversion sheet used for digital radiography, a radiation conversion sheet for digital X-ray photography, in which a phosphor layer formed by mixing phosphor particles and a binder resin is formed on a plastic substrate, is disclosed in JP-A-11-305000. And Japanese Patent Laid-Open No. 2000-155198.

On the other hand, the photoelectric conversion image pickup device is formed by two-dimensionally arranging pixels (each side having a size of 50 to 300 μm) including thin film transistors and electric wiring on a glass substrate. Further, an IC for reading information is arranged around the photoelectric conversion image pickup device (Japanese Patent Laid-Open No. 10-34).
1013 publication).

Japanese Laid-Open Patent Publication No. 10-341013 discloses an X-ray visible light conversion element (radiation conversion sheet) on the surface of the photoelectric conversion element as a measure against external noise of the photoelectric conversion image pickup element.
Has been disclosed, in which a conductive member is laminated on the surface of the substrate on which the X-ray visible light conversion element is formed, which is opposite to the surface on which the phosphor is formed.

Further, in Japanese Unexamined Patent Publication No. 10-160898, a metal reflective layer is formed on one surface of a resin substrate, a particulate phosphor is formed on the surface of the metal reflective layer, and further visible on the surface of the phosphor layer. A radiation conversion sheet having a protective layer transparent to light rays is disclosed. In the disclosed configuration, when the resin substrate / metal reflective layer / particulate phosphor / metal protective layer of protective layer is provided, the phosphor is taken out through the protective layer as compared with the case where the metal reflective layer is not provided. The amount of emitted light increases. However, as a result of the research and development by the present inventors,
The presence of the metal reflection layer causes a problem that the resolution of the image is reduced as compared with the case where the metal reflection layer is not provided. further
The thickness of the reflective layer disclosed in Japanese Patent Laid-Open No. 10-160898 is 10 μm or less, and no effect as an electromagnetic shield layer was recognized.

[0006]

A conventional radiation conversion sheet will be described below with reference to FIG.

In FIG. 10, a radiation conversion sheet 2 (consisting of a substrate and a phosphor layer) is formed on the surface of a photoelectric conversion image pickup device 21.
Adhesives 24 and 25 are used in the step of sequentially laminating 2 and the conductive material layer (conductive member) 23, respectively. A thermosetting resin is mainly used as a material for the adhesives 24 and 25.

This is because the solvent evaporation curing type adhesive represented by vinyl acetate resin remains in the adhesive layer when the surfaces having a remarkably large area with respect to the thickness of the adhesive layer are stuck together. The solvent remains, which adversely affects the durability of the photoelectric conversion element. Further, although the ultraviolet curing type adhesive cures quickly, most of the photoelectric conversion image pickup device, the radiation conversion sheet, and the conductive material layer do not sufficiently transmit ultraviolet rays, and thus the curing of the adhesive is hindered.

In order to laminate the radiation conversion sheet and the conductive material layer on the surface of the photoelectric conversion image pickup device using an adhesive made of a thermosetting resin, a heating step of about 60 ° C. to 120 ° C. is required. Since the photoelectric conversion image pickup device 21, the radiation conversion sheet 22, and the conductive material layer 23 have different thermal expansion coefficients, warpage occurs in the bonded object during heat bonding, and the photoelectric conversion image pickup device 21, the radiation conversion sheet 22, and the conductivity. Stress is generated in each of the material layers 23. With these stresses,
There has been a problem that the phosphor layer in the radiation conversion sheet causes delamination, resulting in a defective product. In particular, in the phosphor layer formed on the surface of the base using a binder resin as the particulate phosphor, if the addition amount of the binder resin is 10% by weight or less in order to improve the light emission amount or the sensitivity, The probability of delamination within the body layer is increased.

Therefore, if measures such as lowering the curing temperature of the adhesive are taken, new problems such as lowering the heat resistance of the adhesive material occur.

The use of a room temperature curing adhesive increases the curing time and the cost.

[0012] In the conventional method, the cost is high because of the single-wafer process of laminating one conductive material layer for each sensor. If a defect occurs in the step of attaching the conductive material layers, the photoelectric conversion image pickup device portion, which has the highest production cost, must be disposed of, resulting in an increase in cost.

On the other hand, in the method of manufacturing the radiation conversion sheet, forming the phosphors on the substrate one by one corresponding to the size of the photoelectric conversion image pickup device of the X-ray imaging apparatus increases the production cost. I don't know. Further, forming the phosphor directly on the surface of the photoelectric conversion image pickup device is also performed unless the yield of the phosphor formation process approaches 100% because the production cost of the photoelectric conversion image pickup device is significantly higher than that of the phosphor. Absent. At present, a radiation conversion sheet is continuously produced by a coating solution in which a particulate phosphor is dissolved in a solvent together with a binder resin, roll coating, die coating, blade coating or the like on a substrate. Therefore, a roll of the radiation conversion sheet having a length of several tens to several hundreds of meters can be produced in one step.

After conducting a defect inspection on the surface of the phosphor, a portion having few defects is cut out and used as a radiation conversion sheet for digital X-ray photography.

Further, in order for the conductive material layer to sufficiently function as an electromagnetic shield layer, it is desirable to connect the ground terminal to the conductive material layer.

The terminal for connecting the ground is formed around the radiation converting sheet for digital X-ray imaging after cutting a good product from the radiation converting sheet of the roll into a radiation converting sheet for digital X-ray imaging. If the ground terminal is present in the portion where the image is captured, the ground terminal is reflected in the captured image, which is not preferable.

[0017]

The radiation conversion sheet of the present invention comprises a support substrate having at least a conductive material layer and a resin layer, and a phosphor layer formed on the surface of the resin layer of the support substrate. Be prepared.

The radiation conversion sheet of the present invention comprises a support substrate having at least a first resin layer, a conductive material layer and a second resin layer, and a phosphor layer formed on the surface of the second resin layer. And ,.

Further, the radiation conversion sheet of the present invention comprises a support substrate having at least a first resin layer, a conductive material layer and a second resin layer, and a phosphor layer formed on the surface of the second resin layer. And an adhesive force at an interface between the first resin layer and the conductive material layer is smaller than an adhesive force at an interface between the second resin layer and the conductive material layer. To do.

The radiation conversion sheet of the present invention comprises a first resin layer, a first adhesive, a conductive material layer, a second adhesive,
A support substrate having at least a second resin layer, and a phosphor layer formed on the surface of the second resin layer, wherein the interface between the first resin layer and the first adhesive is adhered. The force is P ₁ , the adhesive force at the interface between the first adhesive and the conductive material layer is P ₂ , the adhesive force at the interface between the conductive material layer and the second adhesive is P ₃ , When the adhesive force at the interface between the second adhesive and the second resin layer is P ₄ , the adhesive force P ₂
Is smaller than the other adhesion forces P ₁ , P ₃ and P ₄ .

A radiation imaging apparatus of the present invention and a method for manufacturing the same,
And the radiation imaging system uses the radiation conversion sheet of the present invention.

Radiation means X-rays, α, β, γ rays and the like.

According to the present invention, it is possible to provide a radiation conversion sheet which is resistant to electromagnetic noise and is used in an inexpensive radiation imaging apparatus.

Further, according to the present invention, it is possible to provide a radiation conversion sheet capable of efficiently producing a noise-preventing earth terminal of the radiation conversion sheet from a continuously produced roll of the radiation conversion sheet.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of an embodiment of the radiation conversion sheet of the present invention. As shown in FIG. 1, a resin substrate (A) 2 serving as a resin layer is laminated on one surface of a conductive material layer (conductive member) 1, and a phosphor layer 3 is formed on the surface of the resin substrate 2.
Are stacked. A phosphor protective layer 4 may be provided on the surface of the phosphor layer 3 as required. The protective layer 4 is preferably made of a material that transmits light such as visible light 6 generated from the phosphor of the phosphor layer 3. Radiation 5 such as X-rays passes through the conductive material layer 1 and the resin substrate (A) 2 and enters the phosphor layer 3, and is converted into light such as visible light 6 by the phosphor layer 3 and the protective layer 4 is turned on. It is transmitted and emitted.

FIG. 2 is a schematic sectional view of another embodiment of the radiation conversion sheet of the present invention. As shown in FIG. 2, the phosphor layer 3 is formed on a support substrate in which a conductive material layer (conductive member) 1 is sandwiched between a resin substrate (A) 2 which is a resin layer and a resin substrate (B) 7 which is a resin layer. It is stacked. A phosphor protective layer 4 may be provided on the surface of the phosphor layer 3 as required.
The protective layer 4 of the phosphor is preferably made of a material that transmits light such as visible light 6 generated from the phosphor. Radiation 5 such as X-rays passes through the resin substrate (B) 7, the conductive material layer 1, and the resin substrate (A) 2 and enters the phosphor layer 3, and the visible light 6 is emitted from the phosphor layer 3.
The light is converted into light, and the like is transmitted through the protective layer 4 and emitted.

In the case of a radiation conversion sheet used for digital X-ray photography for photographing a fine image, high resolution is required. In that case, the resin substrate (A) 2 to be the resin layer
Preferably does not transmit the light emitted from the phosphor.

When the resin substrate (A) 2 transmits light, the light emitted from the phosphors of the phosphor layer 3 passes through the resin substrate 2 and is reflected by the conductive material layer 1. As a result, the sensitivity of the radiation conversion sheet increases, but when the light reflected by the surface of the conductive material away from the phosphor enters the phosphor layer 3 again, passes through the phosphor, and reaches the photoelectric conversion image sensor, the photoelectric conversion image sensor is photoelectrically converted. The resolution of the image captured by the conversion image sensor is reduced.

In the present embodiment, the surface of the resin substrate (A) 2 of the radiation converting sheet functions as a scattering / reflecting surface so that the photoelectric conversion image pickup device has high resolution and high sensitivity. In that case, the resin substrate (A) 2 is formed of a material in which particles having a light reflecting function such as titanium oxide, calcium carbonate, and nickel particles are mixed in a resin. The light reflectance of the resin substrate (A) 2 can be measured using an integrating sphere, and the light reflectance is 80 at a wavelength of 400-700 nm.
% Or more is preferable. As the degree of scattering reflectance of the surface of the resin substrate (A), the surface reflectance of the resin substrate (A) in the reflectance measurement at 45 ° incidence and 45 ° reflection is preferably 20% or less. When the 45-degree reflectance is 20% or more, the resolution of an X-ray image using a phosphor layer made of particulate phosphor tends to decrease. The content of the reflective particles in the resin substrate (A) 2 is preferably 5-40% by weight. When the content of the reflective particles is 5% or less, the reflectance measured by the integrating sphere does not exceed 80%, and the content of the reflective particles is 40% or less.
This is because the resin substrate becomes brittle when the content is more than 100% and the resin substrate A is destroyed even by a slight deformation, and thus does not function as a substrate of the radiation conversion sheet.

The resin material used for the resin substrate (A) 2 is a cellulosic resin which can be solvent-coated, for example, cellulose acetate, cellulose propionate, cellulose acetate butyrate, polyester such as polyethylene terephthalate, polystyrene, polymethylmethacrylate, Film-like resin can be used for plastics such as polyamide, polyimide, vinyl chloride vinyl acetate copolymer, and polycarbonate.

The conductive material layer (conductive member) 1 is preferably a metal, metal alloy or conductive organic substance having a thickness of 5 μm to 100 μm. If the thickness is 1 μm or less, the effect of preventing electrical noise is low, and if the thickness is 100 μm or more, the absorption of X-rays becomes large and the dose of X-rays incident on the radiation conversion sheet decreases.
This is because the sensitivity of the digital X-ray imaging apparatus is lowered. The conductive material layer preferably has a high X-ray transmittance.

When the conductive material layer (conductive member) 1 is made of a metal material, magnesium, magnesium alloys, aluminum, and aluminum alloys are preferable because they have a low X-ray absorption rate.

When the conductive material layer (conductive member) 1 is a conductive organic substance, a conductive carbon film can be used.

Further, as the conductive material layer of the radiation conversion sheet used for the photoelectric conversion image pickup device, a light shielding material for blocking light other than light generated from the phosphor layer, that is, light incident from the outside from passing through the phosphor layer. It is preferable that This is because when light other than the light generated from the phosphor layer enters the photoelectric conversion image pickup device, it is detected as shooting noise.

In order to function as a light shielding material, the visible light transmittance of the conductive material layer is preferably 1% or less, more preferably 0.1% or less.

As a method for producing the phosphor layer according to the present invention, first, a particulate phosphor is mixed with a binder such as nitrification cotton in a predetermined amount, and then an organic solvent is added thereto to obtain an appropriate viscosity. A phosphor coating solution is prepared, and the coating solution is applied onto the resin substrate A by a roll coater, a doctor blade coat or the like, and dried to form a phosphor layer. Further, the steps of applying and drying may be repeated to form a plurality of phosphor layers.

The drying temperature is within a temperature range in which the resin substrate (A) 2 or the resin substrate (B) 7 is not thermally deformed or decomposed. Generally, it is performed at about 60 to 120 ° C.

Examples of the organic solvent used for preparing the phosphor coating solution include ethanol, methyl ethyl ether, butyl acetate, ethyl acetate, ethyl ether and xylene. If necessary, a dispersant such as phthalic acid, stearic acid or acrylic acid, or a plasticizer such as triphenyl phosphate or diethyl phthalate is added to the phosphor coating liquid.

Firefly used in the radiation conversion sheet of the present invention
As an optical body, Gd₂O₂S: Tb, Y₂O₂S: Tb,
(Gd, Y)₂O₂S: Tb, La₂O₂S: Tb, (G
d, Y) ₂O₂S: Tb: Tm, GdTaO_Four: Tb, G
d₂O₃・ Ta₂O_Five・ B₂O₃: Tb, CaWO_Four, BaS
O_Four: Pb, LaOBr: Tm, LaOBr: Tb, H
fO ₂: Ti, HfP₂O₇: CU, CdWO_Four, YTaO
_Four, YTaO_Four: Tm, YTaO_Four: Nb, ZnS: A
g, high efficiency by X-ray excitation such as BaFCl: Eu
Use any phosphor that emits instant light.
You can On the other hand, imaging play that utilizes photostimulability
Firefly as a radiation conversion sheet for digital X-ray photography
When used as an optical layer, BaFBr: Eu²⁺,
BaFI: Eu²⁺, BaF (Br, I): Eu²⁺, Zn
S: Cu, Pb, BaO · xAl₂O₃: Eu²⁺(However,
0.8 ≦ x ≦ 10), La₂O₂S: EU, Sm, Sr
S: Uses stimulable phosphors such as EU and Sm
it can.

As the binder, in addition to nitrified cotton, cellulose acetate, ethyl cellulose, polyvinyl butyral, cotton-like polyester, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyalkyl (meth) acrylate, polycarbonate, polyurethane, cellulose acetate butyrate. , Polyvinyl alcohol, gelatin, as long as it is known as a binder for radiation conversion sheets,
There is no particular limitation.

Although not essential, a protective film is further formed on the surface of the phosphor layer formed on the surface of the resin substrate A as described above, if necessary. To form a protective film, a cellulose derivative such as cellulose acetate, nitrocellulose, or cellulose acetate butyrate or a plastic such as polyvinyl chloride or polymethylmethacrylate is dissolved in a solvent to prepare a coating liquid for a protective film having an appropriate viscosity. Then, this is applied onto the phosphor layer prepared above and dried. Alternatively, using a urethane acrylate-based UV curable resin, coating,
It can be formed by UV curing. Alternatively, the protective film may be formed by laminating a preformed protective film, for example, a transparent plastic film such as polyethylene terephthalate, polyvinylidene chloride, or polyamide on the phosphor layer. The protective layer of the fluorescent substance needs to sufficiently transmit the light generated from the fluorescent substance.
It is preferable that 80% or more of 0-700 nm light is transmitted.

FIG. 3 shows the radiation conversion sheet of FIG.
1 is a schematic view of a cross section of a digital X-ray imaging apparatus having a configuration in which a photoelectric conversion image pickup element (photoelectric conversion sensor) 9 is laminated via 0. As the adhesive 10, an optically transparent thermosetting resin, a hot melt adhesive, or a reactive hot melt adhesive is used. An adhesive that transmits 80% or more of light having a wavelength of 400 to 700 nm is preferable. This is because when it is 80% or less, the light generated from the phosphor is absorbed and the luminous efficiency is lowered, and the sensitivity of the radiation conversion sheet is lowered. The conductive material layer 1 is connected to the ground terminal 8.

FIG. 4 shows a schematic diagram of a cross section of a digital X-ray imaging apparatus according to a modification of the present invention. This is an example in which two layers of the conductive material layer 1 are provided via the resin layer 11. Conductive material layer 1 is 2
By providing the layers, it is possible to obtain a digital X-ray imaging apparatus in which electrical noise from the outside is further reduced. The two conductive material layers are both connected to the ground terminal.

FIG. 5 is a schematic sectional view of another embodiment of the radiation converting sheet of the present invention. 5, the same components as those in FIG. 2 are designated by the same reference numerals.

A resin substrate (A) 2 to be a resin layer is laminated on one surface of the conductive material layer 1 and a resin substrate (B) 7 to be a resin layer is laminated on the other surface of the resin substrate. Board 2
The phosphor layer 3 is laminated on the surface of the. A phosphor protective layer 4 may be provided on the surface of the phosphor layer 3 as required. The protective layer 4 of the phosphor is preferably made of a material that transmits light such as visible light 6 generated from the phosphor. Radiation 5 such as X-rays passes through the resin substrate (B) 7, the conductive material layer 1, and the resin substrate (A) 2 and enters the phosphor layer 3, and the phosphor layer 3 converts the visible light 6 into light. It is converted and emitted through the protective layer 4.

FIG. 6 shows a digital X with a ground terminal connected.
It is a cross-sectional schematic diagram of the radiation conversion sheet for radiography. 6, the same components as those in FIG. 5 are designated by the same reference numerals.

A grounding terminal is formed by making a cut at the end of a resin substrate (B) 7 to be a resin layer for forming a grounding terminal on the radiation converting sheet shown in FIG. 5 and removing only the resin material of the resin substrate 7. Get a connection with 8. When a part of the resin substrate (B) 7 is peeled off from the conductive material layer 1,
The surface of the resin substrate (B) other than peeling can be protected so as not to peel. However, when the resin material of the ground terminal connecting portion is peeled off, at least peeling does not occur between the conductive material layer 1 and the resin substrate (A). In the present embodiment, in order to prevent this peeling, at least the adhesiveness between the resin substrate (B) 7 and the conductive material layer 1 should be close to that between the conductive material layer 1 and the resin substrate (A) 2. It was lower than sex.

In order to obtain such an adhesive relationship, first, the surface of the conductive material layer 1 in contact with the resin substrate (B) 7 is released. As the release treatment material, a silicon-based coating material or a siloxane-based coating material can be used.

Secondly, the material of the resin substrate (B) 7 is selected such that it has a poorer adhesion to the conductive material layer 1 than the resin substrate (A). As the material of the resin substrate (B) 7, the resin substrate (A)
Choose a polymer with a polarity lower than 2. Specifically, the resin substrate (A) 2 is polyethylene terephthalate, acrylic resin, nylon resin, polycarbonate, resin substrate (B)
Polymers having no polar group such as polystyrene, polypropylene and polyethylene are preferred.

FIG. 7 shows a schematic sectional view of still another embodiment of the present invention. A phosphor layer is laminated on a support substrate in which a conductive material layer 1 is sandwiched between a resin substrate (A) 2 and a resin substrate (B) 7. The resin substrate (A) 2 and the conductive material layer 1 are bonded with an adhesive (A) 14, and the conductive material layer 1 and the resin substrate (B) 7 are bonded with an adhesive (B) 13. To be done.

In the present embodiment, when a part of the end of the resin substrate (B) 7 is removed and the ground terminal is formed at the end of the radiation conversion sheet, the resin substrate (B) 7 is bonded even after peeling. It is desirable to prevent the agent (B) 13 from remaining on the surface of the conductive material layer 1 in order to produce the ground terminal with high productivity. Therefore, it is important to design the adhesive force between the adhesive (B) 13 and the conductive material layer 1 to be lower than the adhesive force between other layers.

In order to make the adhesive strength of the adhesive (B) 13 different between the conductive material layer 1 and the surface of the resin substrate (B) 7, the adhesive (B) 13 is a hot melt adhesive. When used, the resin substrate (B) is treated by corona treatment only on the resin substrate side surface to improve wettability.
It is possible to improve the adhesive force between the adhesive 7 and the adhesive (B) 13 more than the adhesive force between the conductive material layer 1 and the adhesive (B) 13.

It is also desirable to select a material whose solubility parameter of the adhesive (B) 13 is closer to that of the resin substrate (B) 7 than that of the conductive material layer 1.

Also in the embodiment shown in FIGS. 5 to 8, as in the embodiment shown in FIGS. 1 to 4, it is obtained in the case of a radiation conversion sheet used for digital X-ray imaging for capturing a fine image. The same material and reflectance of the resin substrate, the thickness and material of the conductive material layer, the manufacturing method and material of the phosphor layer, and the material of the protective film can be used.

FIG. 8 shows the radiation conversion sheet of FIG.
1 is a schematic view of a cross section of a digital X-ray imaging apparatus having a configuration in which a photoelectric conversion image pickup element (photoelectric conversion sensor) 9 is laminated via 0. As the adhesive 10, an optically transparent thermosetting resin, a hot melt adhesive, or a reactive hot melt adhesive is used. An adhesive that transmits 80% or more of light having a wavelength of 400 to 700 nm is preferable. This is because when it is 80% or less, the light generated from the phosphor is absorbed and the luminous efficiency is lowered, and the sensitivity of the radiation conversion sheet is lowered. The conductive material layer 1 is connected to the ground terminal 8.

[0057]

Embodiments of the present invention will be described in detail below with reference to the drawings.

(Example 1) Resin substrate (A) to be a resin layer
As No. 2, a polyethylene terephthalate sheet having a thickness of 188 μm and containing 20% by weight of titanium oxide as a reflective material was used.

An aluminum foil having a thickness of 50 μm is used as the conductive material layer 1, and the resin substrate (A) 2 and the aluminum foil serving as the conductive material layer 1 are laminated in advance with an adhesive for dry lamination having a thickness of 3 μm. Then, it was shaped on a roll having a length of 50 m and a width of 1 m to obtain a phosphor layer coated substrate.

Gd ₂ O ₂ S having an average particle size of 5 μm:
10 parts by weight of Tb phosphor, 1 part by weight of vinyl chloride-vinyl acetate copolymer (binder) and 2 parts of ethyl acetate (organic solvent).
By mixing parts by weight, a phosphor coating solution A was prepared.

Next, Gd ₂ having an average particle diameter of 8 μm
A phosphor coating solution B was prepared by mixing 10 parts by weight of O ₂ S: Tb phosphor, 1 part by weight of vinyl chloride-vinyl acetate copolymer (binder) and 2 parts by weight of ethyl acetate (organic solvent).

On the surface of the phosphor layer coated substrate, the phosphor coating liquid A was used, and the coating weight of the phosphor after coating and drying was 30 mg.
/ Cm ² to evenly coat with a knife coater,
It was dried to form a phosphor layer. Next, phosphor coating liquid B
And the coating weight of the phosphor after coating and drying is 50 mg / cm
^It was evenly coated with a knife coater so as to be ^2, and dried to form a phosphor layer. The coating weight of the entire phosphor layer was 80 mg / cm ² . The solvent was dried at 90 ° C. for 60 minutes.

Next, a vinylidene chloride film having a thickness of 5 μm was laminated as the protective layer 4 to obtain a radiation conversion sheet as shown in FIG.

(Example 2) Resin substrate (A) to be a resin layer
2, white polyethylene terephthalate having a thickness of 188 μm (the same as in Example 1) containing 20% by weight of titanium oxide as a reflective material, and a conductive material layer 1 having a thickness of 10
A transparent carbon terephthalate film having a thickness of 100 μm is used as the resin substrate (B) 7, which is a conductive carbon sheet having a thickness of 100 μm, and the resin substrate (A) 2, the conductive material layer 1, and the resin substrate (B) 7 are laminated. A phosphor-coated substrate was produced by performing thermal welding.

Thereafter, a radiation conversion sheet as shown in FIG. 2 was obtained by the same method as in Example 1.

(Example 3) As the resin substrate (A) 2 and the resin substrate (B) 7, a material of white polyethylene terephthalate (same as in Example 1) having a thickness of 188 μm and containing 20% by weight of titanium oxide was used. , A resin substrate (A) using an aluminum foil having a thickness of 30 μm as the conductive material layer 1
2, the conductive material layer 1 and the resin substrate (B) 7 were laminated by heat welding to prepare a phosphor-coated substrate. Thereafter, in the same manner as in Example 1, a radiation conversion sheet as shown in FIG. 2 was created.

Wavelength of resin substrate (A) 2 400-600n
The light reflectance of the substrate surface measured by hand using an integrating sphere of m is 9
It was 0% or more. Here, the light reflectance was measured using a spectrophotometric system using an integrating sphere.

(Example 4) The radiation conversion sheet prepared in Example 3 was used as a photoelectric conversion image pickup device using a thermosetting adhesive (XSG5 manufactured by Kyoritsu Chemical Co., Ltd.) as an adhesive 10, as shown in FIG. The photoelectric conversion sensor 9 was laminated on the light-receiving surface, the ground terminal 8 was attached to a part of the conductive material layer 1 and connected to the ground to manufacture a digital X-ray imaging apparatus. Thus
A digital X-ray imaging apparatus that is less affected by external electrical noise could be manufactured at low cost.

(Comparative Example 1) A radiation conversion sheet 22 was prepared by forming a phosphor layer equivalent to that of Example 1 on white polyethylene terephthalate having a thickness of 188 μm and forming a protective layer.

A conductive material layer 23 was prepared by laminating a 30 μm thick aluminum foil on one surface of a 188 μm thick polyethylene sheet.

The radiation conversion sheet 22 is applied to the photoelectric conversion image pickup device.
Are bonded at a temperature of 70 ° C. with a thermosetting adhesive, and then the conductive material layer 23 is further heated at a temperature of 70 ° C. with a thermosetting adhesive.
It was cured and adhered at 5 ° C. for 5 hours. A product in which delamination of the phosphor was found after adhesion appeared with a probability of 40%.

[0072]

[Table 1] (Example 5) As the resin substrate (A) 2 to be the resin layer, a polyethylene terephthalate sheet containing 20% by weight of titanium oxide and having a thickness of 188 μm was used.

Clan Better G2 (manufactured by Kurashiki Spinning Co., Ltd.) having a thickness of 5 μm was used as the adhesive A, and the conductive material layer 1 had a thickness of 3 μm.
An aluminum foil of 0 μm was used.

For the resin layer (B) 7, 1% styrene resin is used.
A solution having 0 parts by weight dissolved in 10 parts by weight of butyl acetate and 10 parts by weight of xylene was applied to form a layer having a thickness of 5 μm.

The resin substrate (A) 2 and the aluminum foil are preliminarily laminated with an adhesive A having a thickness of 3 μm, and the length is 50
It was shaped on a roll having a width of m and a width of 1 m to obtain a phosphor layer coated substrate.

The average particle size is 5 μm. Gd ₂ O
₂ S: Tb phosphor 10 parts by weight, vinyl chloride-vinyl acetate copolymer (binder) 1 part by weight and ethyl acetate (organic solvent) 2 parts by weight were mixed to prepare phosphor coating solution A.

Next, the average particle diameter is 8 μm. Gd ₂
A phosphor coating solution B was prepared by mixing 10 parts by weight of O ₂ S: Tb phosphor, 1 part by weight of vinyl chloride-vinyl acetate copolymer (binder) and 2 parts by weight of ethyl acetate (organic solvent).

On the surface of the phosphor layer-coated substrate, the phosphor coating liquid A was used, and the phosphor coating weight after coating and drying was 30 mg.
/ Cm ² to evenly coat with a knife coater,
It was dried to form a phosphor layer. Next, phosphor coating liquid B
And the coating weight of the phosphor after coating and drying is 50 mg / cm
^It was evenly coated with a knife coater so as to be ^2, and dried to form a phosphor layer. The coating weight of the entire phosphor layer was 80 mg / cm ² . Solvent is dried at 90 ℃, 60
I went for a minute.

Next, a vinylidene chloride film having a thickness of 5 μm was laminated as a protective layer to obtain a radiation conversion sheet having a length of 100 m.

After the radiation conversion sheet is prepared, it is cut out as a digital X-ray imaging radiation conversion sheet to obtain the radiation conversion sheet shown in FIG. When the resin layer B on the outer peripheral portion is removed, only the resin layer B can be peeled off, and the radiation converting sheet for digital X-ray photography shown in FIG. 9 is completed.

(Example 6) Resin substrate (A) to be a resin layer
As 2 the thickness was 188μ containing 20% by weight of titanium oxide.
m of white polyethylene terephthalate (the same as in Example 1), a conductive carbon sheet having a thickness of 10 μm as the conductive material layer 1, a transparent polyethylene terephthalate having a thickness of 188 μm as the resin substrate (B) 7 serving as a resin layer, and an adhesive A. Clanbetter G1200 (thickness 10 μm) was used as the adhesive, and Clanbetter G2 (thickness 10 μm) was used as the adhesive B.

Thereafter, a radiation conversion sheet as shown in FIG. 7 was obtained in the same manner as in Example 1. Clan Better G2
Adhesion between PET (thickness 10 μm) and PET is measured by T-type peel test (2
5mm in width (5mm width), adhesion to carbon film is 8
It was 00 g, and when the resin surface (B) was peeled by half-cutting to the carbon surface with a hollow blade, the adhesive B was peelable together with the resin substrate (B). As a result, no defects,
A radiation conversion sheet for digital radiography having no residue of adhesive B was completed.

A low-cost digital X-ray imaging apparatus that is resistant to electrical noise and is bonded to a photoelectric conversion image pickup device as shown in FIG. 8 has been completed.

Example 7 As the resin substrate (A) 2 and the resin substrate (B), a material of white polyethylene terephthalate having a thickness of 188 μm and containing 20% by weight of titanium oxide was used. A conductive carbon sheet having a thickness of 10 μm as the conductive material layer 1 and a cranbeta G as the adhesive A
1200 (thickness 10 μm), and Clanbetter G2 (thickness 10 μm) was used as the adhesive B. Thereafter, in the same manner as in Example 1, a radiation conversion sheet as shown in FIG. 7 was created.

Wavelength of resin substrate (A) 2 400-600n
The light reflectance of m was 90% or more.

The light reflectance was measured using a spectrophotometric system using an integrating sphere. 45 degree incidence on the resin substrate surface,
The reflectance at 45 degrees reflection was 8%.

(Example 8) The radiation conversion sheet prepared in Example 7 was used as a photoelectric conversion image pickup device using a thermosetting adhesive (XSG5 manufactured by Kyoritsu Kagaku) as an adhesive 10 as shown in FIG. The photoelectric conversion sensor 9 was laminated on the light-receiving surface, the ground terminal 8 was attached to a part of the conductive material layer 1 and connected to the ground to manufacture a digital X-ray imaging apparatus. In this way, a digital X-ray imaging apparatus that was less affected by electromagnetic noise could be manufactured at low cost.

Comparative Example 2 A radiation conversion sheet 22 was prepared by forming a phosphor layer equivalent to that of Example 5 on white polyethylene terephthalate having a thickness of 188 μm and forming a protective layer.

A conductive material layer 23 was prepared by laminating a 30 μm thick aluminum foil on one surface of a 188 μm thick polyethylene sheet.

The radiation conversion sheet 22 is applied to the photoelectric conversion image pickup device.
Are bonded at a temperature of 70 ° C. with a thermosetting adhesive, and then the conductive material layer 23 is further heated at a temperature of 70 ° C. with a thermosetting adhesive.
It was cured and adhered at 5 ° C. for 5 hours. A product in which delamination of the phosphor was observed after adhesion appeared with a probability of 40%.

[0091]

[Table 2] Next, a radiation imaging system using the radiation imaging apparatus according to the present invention will be described.

FIG. 11 shows an application example of the radiation imaging apparatus according to the present invention to a radiation diagnostic system.

X-ray 60 generated by X-ray tube 6050
Reference numeral 60 denotes a photoelectric conversion device 6 which penetrates a chest 6062 of a patient or a subject 6061 and has a scintillator mounted on the upper portion thereof.
It is incident on 040. This incident X-ray has a patient 6061
Contains information about the inside of the body. The scintillator emits light in response to the incidence of X-rays and photoelectrically converts the light to obtain electrical information. This information is converted to digital, image-processed by the image processor 6070, and can be viewed on the display 6080 in the control room.

Further, this information can be transferred to a remote place by a transmission means such as a telephone line 6090, can be displayed on a display 6081 such as a doctor room at another place, or can be stored in a storage means such as an optical disc. It is also possible to diagnose. Also the film processor 6
It is also possible to record by 100 on the film 6110.

[0095]

As described above, according to the present invention,
A radiation conversion sheet that can prevent delamination of the phosphor layer in the radiation conversion sheet can be stably provided at low cost.

Since the delamination of the phosphor layer does not occur even if an adhesive having a high thermosetting temperature is used, the radiation conversion sheet and the photoelectric conversion image pickup element can be bonded at high temperature, and the digital X-ray excellent in heat resistance is obtained. It becomes possible to make a photographing device. Generally, below the heat curing temperature, the adhesive hardly shows any chemical or physical change even if it is reheated.

Further, according to the present invention, it is possible to provide a radiation conversion sheet capable of efficiently producing a noise-preventing earth terminal of the radiation conversion sheet from a continuously produced roll of the radiation conversion sheet.

Further, in the X-ray imaging apparatus using the radiation conversion sheet of the present invention, the resolution of the selected image is high and it is possible to reduce the image defects due to electromagnetic noise at low cost.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an embodiment of a radiation conversion sheet of the present invention.

FIG. 2 is a schematic cross-sectional view of another embodiment of the radiation conversion sheet of the present invention.

FIG. 3 is a schematic cross-sectional view of a digital X-ray imaging apparatus having a configuration in which the radiation conversion sheet of FIG. 2 is laminated on a photoelectric conversion image pickup device via an adhesive.

FIG. 4 is a schematic cross-sectional view of a cross section of a digital X-ray imaging apparatus according to a modification of the present invention.

FIG. 5 is a schematic sectional view of another embodiment of the radiation conversion sheet of the present invention.

FIG. 6 is a schematic sectional view of a radiation converting sheet for digital X-ray photography, to which a ground terminal is connected.

FIG. 7 is a schematic cross-sectional view of still another embodiment of the radiation conversion sheet of the present invention.

8 is a schematic cross-sectional view of a digital X-ray imaging apparatus having a configuration in which the radiation conversion sheet of FIG. 7 is laminated on a photoelectric conversion image pickup device via an adhesive.

FIG. 9 is a schematic cross-sectional view of still another embodiment of the radiation conversion sheet of the present invention.

FIG. 10 is a cross-sectional view showing a conventional X-ray imaging apparatus using a radiation conversion sheet.

FIG. 11 is a diagram showing an application example of the X-ray detection apparatus according to the present invention to an X-ray diagnostic system.

[Explanation of symbols]

1 Conductive material layer (conductive member) 2 Resin substrate A (Resin layer A) 3 Phosphor layer 4 protective layer 5 X-ray (radiation) 6 visible light 7 Resin substrate B (Resin layer B) 8 ground terminal 9 Photoelectric conversion image sensor (photoelectric conversion sensor) 10 adhesive 11 Resin layer 12 Ground terminal connection 13 Adhesive B 14 Adhesive A

Claims (17)

[Claims] 1. A radiation conversion sheet comprising a support substrate having at least a conductive material layer and a resin layer, and a phosphor layer formed on the surface of the resin layer of the support substrate. 2. A radiation conversion comprising: a support substrate having at least a first resin layer, a conductive material layer, and a second resin layer; and a phosphor layer formed on the surface of the second resin layer. Sheet. 3. The radiation conversion sheet according to claim 1, wherein the resin layer contains a light reflecting material. 4. The radiation conversion sheet according to claim 2, wherein the second resin layer contains a light reflecting material. 5. The resin layer has a wavelength of 400 nm-600 n
The radiation conversion sheet according to claim 1, wherein the integrated sphere reflectance of the light of m is 80% or more. 6. The wavelength of the second resin layer is 400 nm-6.
The radiation conversion sheet according to claim 2, wherein the radiation conversion sheet has a scattering reflecting surface having an integrated sphere reflectance of 00 nm light of 80% or more. 7. The radiation conversion sheet according to claim 2, wherein the first resin layer and the second resin layer are made of the same resin material. 8. The radiation conversion sheet according to claim 1, wherein the conductive material layer is made of any element of magnesium, aluminum, carbon and beryllium. 9. The radiation conversion sheet according to claim 1, wherein the conductive material layers are laminated with a plurality of layers and a resin layer interposed therebetween. 10. A support substrate having at least a first resin layer, a conductive material layer, and a second resin layer, and a phosphor layer formed on a surface of the second resin layer, A radiation conversion sheet in which the adhesive force at the interface between the first resin layer and the conductive material layer is smaller than the adhesive force at the interface between the second resin layer and the conductive material layer. 11. A support substrate having at least a first resin layer, a first adhesive, a conductive material layer, a second adhesive, and a second resin layer, and formed on the surface of the second resin layer. It has been provided with a phosphor layer, the adhesion of the adhesion interface between the first adhesive and said first resin layer at the interface between the P _1, the conductive material layer and the first adhesive The force is P ₂ , the adhesive force at the interface between the conductive material layer and the second adhesive is P ₃ , the adhesive force at the interface between the second adhesive and the second resin layer is P ₄ , In the radiation conversion sheet, the adhesive force P ₂ is smaller than the other adhesive forces P ₁ , P ₃ , and P ₄ . 12. The radiation conversion sheet according to claim 10, wherein the second resin layer contains a light reflecting material. 13. The integrated sphere reflectance of the second resin layer is 8
It is 0% or more, The radiation conversion sheet of Claim 10 or Claim 11 characterized by the above-mentioned. 14. The resin material of the first resin layer and the resin material of the second resin layer are the same.
Alternatively, the radiation conversion sheet according to claim 11. 15. A radiation imaging apparatus comprising: the radiation conversion sheet according to claim 2; and a photoelectric conversion image pickup element bonded to the radiation conversion sheet via an adhesive. 16. A method of manufacturing a radiation imaging apparatus, which comprises forming the radiation conversion sheet according to claim 1 and then bonding a photoelectric conversion image pickup element to the radiation conversion sheet via an adhesive. 17. The radiation imaging apparatus according to claim 15, signal processing means for processing a signal from the radiation imaging apparatus, recording means for recording a signal from the signal processing means, and the signal processing. Radiography comprising display means for displaying a signal from the means, transmission processing means for transmitting the signal from the signal processing means, and a radiation source for generating the radiation. system.