WO2009144984A1 - Scintillator panel - Google Patents

Scintillator panel Download PDF

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Publication number
WO2009144984A1
WO2009144984A1 PCT/JP2009/053673 JP2009053673W WO2009144984A1 WO 2009144984 A1 WO2009144984 A1 WO 2009144984A1 JP 2009053673 W JP2009053673 W JP 2009053673W WO 2009144984 A1 WO2009144984 A1 WO 2009144984A1
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WO
WIPO (PCT)
Prior art keywords
substrate
scintillator panel
scintillator
film
panel according
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PCT/JP2009/053673
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French (fr)
Japanese (ja)
Inventor
武彦 庄子
直 有本
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コニカミノルタエムジー株式会社
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Publication of WO2009144984A1 publication Critical patent/WO2009144984A1/en

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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K4/00—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K4/00—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens
    • G21K2004/10—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens with a protective film

Definitions

  • the present invention relates to a scintillator panel that is excellent in brightness and sharpness, can be used over a long period of time without worrying about corrosion damage.
  • radiographic images such as X-ray images have been widely used for diagnosis of medical conditions in the medical field.
  • radiographic images using intensifying screen-film systems have been developed throughout the world as an imaging system that combines high reliability and excellent cost performance as a result of high sensitivity and high image quality achieved over a long history. Used in medical settings.
  • these pieces of image information are so-called analog image information, and free image processing and instantaneous electric transmission such as digital image information that has been developing in recent years cannot be performed.
  • digital radiographic image detection devices represented by computed radiography (CR), flat panel radiation detectors (FPD) and the like have appeared. Since digital radiographic images are directly obtained and images can be directly displayed on an image display device such as a cathode ray tube or a liquid crystal panel, image formation on a photographic film is not always necessary. As a result, these digital X-ray image detection devices reduce the need for image formation by the silver halide photography method, and greatly improve the convenience of diagnosis work in hospitals and clinics.
  • CR computed radiography
  • FPD flat panel radiation detectors
  • a scintillator panel made of an X-ray phosphor having a characteristic of emitting light by radiation is used.
  • luminous efficiency is used. It is necessary to use a high scintillator panel.
  • the light emission efficiency of a scintillator panel is determined by the thickness of the scintillator and the X-ray absorption coefficient of the phosphor.
  • CsI cesium iodide
  • CsI sodium activated cesium iodide
  • TlI thallium iodide
  • Visible conversion efficiency is improved by annealing the deposited Tl) as a post process, and it is used as an X-ray phosphor.
  • Patent Document 1 As another means for increasing the light output, a method for making the substrate on which the scintillator is formed reflective (for example, see Patent Document 1), a method for providing a metal reflective layer on the substrate (for example, Patent Document 2), A method of forming a scintillator on a reflective metal thin film and a transparent organic film covering the metal thin film (see, for example, Patent Document 3) has been proposed.
  • a scintillator As a manufacturing method of a scintillator by a vapor phase method, it is common to form a scintillator on a substrate such as aluminum, amorphous carbon, or glass, and to cover the entire surface of the scintillator with a protective film. Furthermore, a scintillator panel is known in which the entire reflective metal thin film provided on a substrate is covered with a protective film, and a scintillator is deposited on the protective film (see, for example, Patent Document 8).
  • the columnar crystal state of cesium iodide (CsI) is controlled by the degree of vacuum during deposition and the substrate temperature.
  • CsI cesium iodide
  • Patent Document 7 a specific control method has been proposed (see, for example, Patent Document 7), the actual scintillator characteristics are greatly affected by the X-ray absorption rate, surface property, reflectance, surface energy, charging, etc. of the substrate. In some cases, it is difficult to achieve a good columnar crystal state, which is an obstacle to improving the characteristics.
  • an aluminum substrate is less likely to break than a glass substrate, and has an advantage that it is cheaper and easier to process than an amorphous carbon substrate.
  • corrosion due to cesium iodide (CsI) and a columnar crystal state that is better as a glass substrate. There is a problem that it cannot be obtained.
  • Japanese Patent Publication No. 7-21560 Japanese Patent Publication No. 1-240887 JP 2000-356679 A JP 2005-49341 A JP 2006-113007 A JP 2006-138642 A JP 2007-292755 A JP 2001-289952 A JP 2008-51814 A
  • the present invention has been made in view of the above-mentioned problems and situations, and a problem to be solved is to provide a scintillator panel that is excellent in luminance and sharpness, can be used for a long period of time without fear of corrosion damage.
  • the present inventors have found that the polished state of the aluminum substrate before the anodizing treatment, rather than the smoothness of the aluminum substrate after the anodizing treatment, greatly increases the columnar crystal growth. It has been found that it has an influence, and furthermore, it has been found that by making a good columnar crystal state based on this knowledge, performance such as the sharpness of the scintillator panel can be improved, and the present invention has been achieved.
  • Sectional drawing which shows schematic structure of scintillator panel 10 for radiation Expanded sectional view of radiation scintillator panel 10
  • the figure which shows schematic structure of the vapor deposition apparatus 61 Partially broken perspective view showing a schematic configuration of the radiation image detector 100 Enlarged sectional view of the imaging panel 51
  • the scintillator panel of the present invention is a scintillator panel in which a scintillator layer is provided on a substrate made of aluminum or an aluminum alloy coated with an anodized film, and the anodized film is polished by polishing the surface of the substrate. It is characterized in that it is formed by anodizing after flattening so that the roughness is 3.0 ⁇ m or less at the maximum height (Rmax).
  • Rmax maximum height
  • an aspect in which the regular reflectance of visible light at an incident angle of 45 ° on the surface of the substrate on the side where the scintillator layer is formed is 60% or more.
  • the corner portion of the substrate is processed so as to have an arc shape with a curvature radius R.
  • the range of the curvature radius R is preferably 1 to 10 mm.
  • the coating is a resin containing polyester, or a polyparaxylene film in which the coating with the resin is formed on the entire surface of the substrate by a CVD method (Chemical Vapor Deposition; also referred to as “chemical vapor deposition method”). It is preferable that the coating is.
  • the porosity of the anodic oxide film on the substrate is 60% or less.
  • the thickness of the anodic oxide film is preferably 200 to 2000 nm.
  • the scintillator layer is preferably formed by a vapor phase method using an additive containing cesium iodide and at least one thallium compound as a raw material.
  • the scintillator panel of the present invention has a protective film made of resin that covers the entire surface of the scintillator panel. It is preferable that the protective film has a polyparaxylylene film formed by a CVD method.
  • the scintillator panel of the present invention is a scintillator panel in which a scintillator layer is provided on a substrate made of aluminum or an aluminum alloy coated with an anodized film.
  • the anodized film is a surface roughened by polishing. It is characterized in that it is formed by anodizing after flattening so that the degree is 3.0 ⁇ m or less at the maximum height (Rmax).
  • the maximum height (Rmax) is preferably 1.5 ⁇ m or less from the viewpoint of improving luminance characteristics, and more preferably 0.01 to 1.5 ⁇ m.
  • the influence of polishing scratches, streaks, etc. on the substrate made of aluminum or aluminum alloy on the sharpness of the scintillator panel can be suitably evaluated by Rmax and Rz defined in JIS B0601 (1982).
  • the effect of this invention is not acquired in the evaluation after centerline average roughness Ra which is an average of surface property, and an anodizing process.
  • the present inventors have also found that the regular reflectance at an incident angle of 45 ° of the aluminum substrate after the anodizing treatment greatly contributes to the brightness of the scintillator panel.
  • the diffuse reflection component also contributes to the improvement of the brightness of the scintillator panel, the sharpness (MTF) is lowered and the effect of the present invention cannot be obtained.
  • “regular reflectance” is a ratio of light reflected at the same angle to light incident on the surface of the object from a certain angle, and “regular reflectance at an incident angle of 45 °” The reflectance when the incident angle is 45 ° with respect to the substrate.
  • the surface of an object having a high regular reflectance is recognized as a mirror surface by the human eye.
  • the corrosion prevention effect of the anodic oxide film is that the porosity is 60% or less, and the thickness of the anodic oxide film is 200 to 2000 nm. It has been found that the prevention effect is significant.
  • CsI cesium iodide
  • a resin polymer
  • the effect of the present invention can be obtained as long as the anodized film and cesium iodide are insulated.
  • the resin is coated on the entire surface of the substrate by a resin containing polyester or CVD. A resin containing the formed polyparaxylylene is preferable.
  • the corner portion of the substrate is processed so as to have an arc shape with a curvature radius R.
  • the radius of curvature R is 1 to 10 mm from the viewpoint of workability.
  • a substrate made of anodized aluminum or the like In order to make a substrate made of anodized aluminum or the like, it was immersed as an anode in a solution containing sulfuric acid, phosphoric acid, oxalic acid, chromic acid or sulfamic acid, an organic acid such as benzenesulfonic acid, or a mixture thereof. Current is passed through the aluminum plate.
  • An electrolyte concentration of 1 to 70% by weight can be used at a temperature in the range of 0 to 70 ° C, more preferably at a temperature in the range of 35 to 60 ° C.
  • the anode current density, 1 ⁇ 50A / dm may be changed, also give an anodic oxidation film of 1 ⁇ 8g / m 2 Al 2 O 3 ⁇ H 2 O by changing the voltage in the range of 1 ⁇ 100 V Also good.
  • the anodized aluminum plate may subsequently be rinsed with deionized water at a temperature in the range of 10-80 ° C.
  • post-treatment such as sealing may be applied to the anode surface.
  • Sealing the holes in the aluminum oxide layer formed by anodization is a well-known technique in the technical field of aluminum anodization. This technology is, for example, “Belgsch-Nederlands tijdschiff voor Uppervlacktechtechniken van materialen” (surface technology and material process), Volume 24, January 1980, name “Sealing-kalliteminte-alumine-oxidant-alumino-oxidant-alumine-oxidant-alumino-oxidant-alumino-oxidant Sealing quality and sealing control).
  • a metal reflective layer can be separately provided on the substrate in order to increase the light output, but the regular reflectance of visible light at an incident angle of 45 ° of the anodized film is set to 60% or more. As a result, the effect of increasing the light output without the metal reflection layer can be obtained.
  • the metal reflective layer is formed of a metal having a high reflectance in terms of utilization efficiency of emitted light.
  • the metal film layer having high reflectivity include a material containing a substance in the group consisting of Al, Ag, Cr, Cu, Ni, Mg, Pt, and Au. Two or more such metal thin films may be formed.
  • the lower layer is preferably a layer containing Cr from the viewpoint of improving the adhesion to the substrate.
  • a layer made of a metal oxide such as SiO 2 or TiO 2 may be provided in this order on the metal thin film to further improve the reflectance.
  • the “scintillator” refers to a phosphor that absorbs energy of incident radiation such as X-rays and emits electromagnetic waves having a wavelength of 300 nm to 800 nm, that is, electromagnetic waves (light) centered on visible light. .
  • CsI Cesium iodide
  • CsI alone has low luminous efficiency
  • various activators are added.
  • a mixture of CsI and sodium iodide (NaI) in an arbitrary molar ratio can be mentioned.
  • CsI is deposited by vapor deposition of indium (In), thallium (Tl), lithium (Li), potassium (K), rubidium (Rb), sodium ( CsI containing an activating substance such as Na) is preferred.
  • thallium activated cesium iodide (CsI: Tl) is preferable because it has a broad emission wavelength from 400 nm to 750 nm.
  • thallium compound as an additive containing one or more types of thallium compounds according to the present invention, various thallium compounds (compounds having oxidation numbers of + I and + III) can be used.
  • preferred thallium compounds are thallium bromide (TlBr), thallium chloride (TlCl), thallium fluoride (TlF, TlF 3 ), and the like.
  • the melting point of the thallium compound according to the present invention is preferably in the range of 400 to 700 ° C. If the temperature exceeds 700 ° C., the additive in the columnar crystals exists non-uniformly, and the luminous efficiency is lowered.
  • the melting point is a melting point at normal temperature and pressure.
  • the molecular weight of the thallium compound is preferably in the range of 206 to 300.
  • the content of the additive is desirably an optimum amount according to the target performance and the like, but is 0.001 to 50 mol% with respect to the content of cesium iodide, and further 0.1 to It is preferable that it is 10.0 mol%.
  • the thickness of the scintillator layer is preferably 100 to 800 ⁇ m, and more preferably 120 to 700 ⁇ m, from the viewpoint of obtaining a good balance between luminance and sharpness characteristics.
  • a resin that covers at least the scintillator layer forming surface side of the substrate As a resin that covers at least the scintillator layer forming surface side of the substrate, a resin containing polyester that can be easily processed with a spin coater or a wire bar, or a CVD method (Chemical Vapor Deposition; also referred to as “chemical vapor deposition method”) is easy. A polyparaxylylene film that can be coated on the entire surface of the substrate is suitable.
  • the scintillator panel of the present invention is characterized by having a protective film made of resin covering the entire surface.
  • the protective film is for moisture-proofing the scintillator layer and suppressing deterioration of the scintillator layer, and is made of a material having low moisture permeability.
  • a polyethylene terephthalate film PET
  • PET polyethylene terephthalate film
  • a polyester film, a polymethacrylate film, a nitrocellulose film, a cellulose acetate film, a polypropylene film, a polyethylene naphthalate film, or the like can be used.
  • Polyparaxylylene (10 to 14 S / cm) is suitable in the present invention because a polyparaxylylene film can be easily formed on the entire surface of the scintillator panel by the CVD method.
  • FIG. 1 is a cross-sectional view showing a schematic configuration of the radiation scintillator panel 10.
  • FIG. 2 is an enlarged cross-sectional view of the radiation scintillator panel 10.
  • FIG. 3 is a diagram showing a schematic configuration of the vapor deposition apparatus 61.
  • the vapor deposition apparatus 61 has a box-shaped vacuum vessel 62, and a vacuum vapor deposition boat 63 is disposed inside the vacuum vessel 62.
  • the boat 63 is a member to be filled as an evaporation source, and an electrode is connected to the boat 63. When a current flows through the electrode to the boat 63, the boat 63 generates heat due to Joule heat.
  • the boat 63 is filled with a mixture containing cesium iodide and an activator compound, and an electric current flows through the boat 63 so that the mixture can be heated and evaporated. It has become.
  • An alumina crucible around which a heater is wound may be applied as the member to be filled, or a refractory metal heater may be applied.
  • a holder 64 for holding the substrate 1 is disposed inside the vacuum vessel 62 and directly above the boat 63.
  • the holder 64 is provided with a heater (not shown), and the substrate 1 mounted on the holder 64 can be heated by operating the heater.
  • the substrate 1 When the substrate 1 is heated, the adsorbate on the surface of the substrate 1 is removed and removed, or an impurity layer is formed between the substrate 1 and the scintillator layer (phosphor layer) 2 formed on the surface. Can be prevented, the adhesion between the substrate 1 and the scintillator layer 2 formed on the surface thereof can be enhanced, or the film quality of the scintillator layer 2 formed on the surface of the substrate 1 can be adjusted. It has become.
  • the holder 64 is provided with a rotation mechanism 65 that rotates the holder 64.
  • the rotating mechanism 65 is composed of a rotating shaft 65a connected to the holder 64 and a motor (not shown) as a driving source for the rotating shaft 65. When the motor is driven, the rotating shaft 65a rotates to displace the holder 64 in the boat. It can be rotated in a state of being opposed to 63.
  • a vacuum pump 66 is disposed in a vacuum vessel 62 in addition to the above configuration.
  • the vacuum pump 66 exhausts the inside of the vacuum container 62 and introduces gas into the vacuum container 62.
  • the inside of the vacuum container 62 has a gas atmosphere at a constant pressure. Can be maintained below.
  • the evaporation device 61 described above can be suitably used.
  • a method for producing the radiation scintillator panel 10 using the evaporation device 61 will be described.
  • ⁇ Anodic oxidation treatment of substrate> After buffing the surface so that the surface roughness (Rmax) of the surface of the 0.5 mm thick aluminum plate 1 on which the phosphor is to be formed becomes a predetermined value, the surface is kept at 50 ° C. containing 2% of a surfactant. It is immersed in a heated degreasing solution for 60 seconds and then washed with water for 30 seconds. Next, the substrate is etched with a 10% NaOH aqueous solution heated to 50 ° C. for 30 seconds and then washed with water for 30 seconds. Thereafter, it is washed with a 10% NHO3 aqueous solution for 30 seconds and then washed with water for 30 seconds.
  • the aluminum plate is immersed in an electrolytic solution, the substrate is subjected to an electrolytic treatment using an anode and a carbon plate as a counter electrode, washed with water for 10 seconds after the treatment, and dried at 100 ° C. for 5 minutes, whereby the surface of the aluminum plate An anodic oxide film 3a was formed.
  • a polyparaxylylene film 3b having a thickness of about 2 ⁇ m is formed on the entire surface of the substrate having a thickness of 0.5 mm by a CVD method.
  • the substrate 1 provided with the reflection layer as described above is attached to the holder 64, and the boat 63 is filled with a powdery mixture containing cesium iodide and thallium iodide (preparation step).
  • the distance between the boat 63 and the substrate 1 is set to 100 to 1500 mm, and the vapor deposition process described later is performed while maintaining the range of the set value.
  • the vacuum pump 66 is operated to evacuate the inside of the vacuum vessel 62, and the inside of the vacuum vessel 62 is brought to a vacuum atmosphere of 0.1 Pa or less (vacuum atmosphere forming step).
  • under vacuum atmosphere means under a pressure atmosphere of 100 Pa or less, and preferably under a pressure atmosphere of 0.1 Pa or less.
  • an inert gas such as argon is introduced into the vacuum vessel 62, and the inside of the vacuum vessel 62 is maintained in a vacuum atmosphere of 0.1 Pa or less.
  • an inert gas such as argon is introduced into the vacuum vessel 62, and the inside of the vacuum vessel 62 is maintained in a vacuum atmosphere of 0.1 Pa or less.
  • the heater of the holder 64 and the motor of the rotating mechanism 65 are driven, and the substrate 1 attached to the holder 64 is rotated while being heated while facing the boat 63.
  • the cesium iodide (CsI) forming the scintillator layer 2 has a high hygroscopic property, and if left exposed, absorbs water vapor in the air and deliquesces. Therefore, in order to prevent this, the protective layer 4 is formed by covering the entire surface of the scintillator panel with polyparaxylylene to a thickness of 5 to 30 ⁇ m by the CVD method. Since there is a gap in the columnar crystal of CsI, and polyparaxylylene enters this narrow gap, the protective layer is in close contact with cesium iodide (CsI).
  • CsI cesium iodide
  • the scintillator panel 10 for radiation according to the present invention can be manufactured.
  • FIG. 4 is a partially broken perspective view showing a schematic configuration of the radiation image detector 100.
  • FIG. 5 is an enlarged cross-sectional view of the imaging panel 51.
  • the radiation image detector 100 includes an imaging panel 51, a control unit 52 that controls the operation of the radiation image detector 100, a rewritable dedicated memory (for example, a flash memory), and the like.
  • a memory unit 53 that is a storage unit that stores an image signal output from the power source unit 54, a power supply unit 54 that is a power supply unit that supplies power required to drive the imaging panel 51 and obtain an image signal, It is provided inside the body 55.
  • the housing 55 includes a communication connector 56 for performing communication from the radiation image detector 100 to the outside as necessary, an operation unit 57 for switching the operation of the radiation image detector 100, and preparation for radiographic imaging.
  • a display unit 58 that indicates completion or a predetermined amount of image signal has been written in the memory unit 53 is provided.
  • the radiation image detector 100 is provided with the power supply unit 54 and the memory unit 53 for storing the image signal of the radiation image, and the radiation image detector 100 is detachable via the connector 56, the radiation image detector is provided. It can be set as the portable structure which can carry 100.
  • the imaging panel 51 includes a radiation scintillator panel 10 and an output board 20 that absorbs electromagnetic waves from the radiation scintillator panel 10 and outputs an image signal.
  • the radiation scintillator panel 10 is disposed on the radiation irradiation surface side, and is configured to emit an electromagnetic wave corresponding to the intensity of incident radiation.
  • the output substrate 20 is provided on the surface opposite to the radiation irradiation surface of the radiation scintillator panel 10, and in order from the radiation scintillator panel 10 side, the diaphragm 20a, the photoelectric conversion element 20b, the image signal output layer 20c, and the substrate 20d. It has.
  • the diaphragm 20a is for separating the scintillator panel 10 for radiation and other layers.
  • the photoelectric conversion element 20 b includes a transparent electrode 21, a charge generation layer 22 that is excited by electromagnetic waves that have passed through the transparent electrode 21 to enter the light, and generates a charge, and a counter electrode 23 that is a counter electrode for the transparent electrode 21.
  • the transparent electrode 21, the charge generation layer 22, and the counter electrode 23 are arranged in this order from the diaphragm 20a side.
  • the transparent electrode 21 is an electrode that transmits an electromagnetic wave that is photoelectrically converted, and is formed using a conductive transparent material such as indium tin oxide (ITO), SnO 2 , or ZnO.
  • ITO indium tin oxide
  • SnO 2 SnO 2
  • ZnO ZnO
  • the charge generation layer 22 is formed in a thin film on one surface side of the transparent electrode 21, and contains an organic compound that separates charges by light as a compound capable of photoelectric conversion. Each of them contains a conductive compound as an electron acceptor. In the charge generation layer 22, when an electromagnetic wave is incident, the electron donor is excited to emit electrons, and the emitted electrons move to the electron acceptor, and charge, that is, holes and electrons, are transferred into the charge generation layer 22.
  • examples of the conductive compound as the electron donor include a p-type conductive polymer compound.
  • examples of the p-type conductive polymer compound include polyphenylene vinylene, polythiophene, poly (thiophene vinylene), polyacetylene, polypyrrole, Those having a basic skeleton of polyfluorene, poly (p-phenylene) or polyaniline are preferred.
  • Examples of the conductive compound as the electron acceptor include an n-type conductive polymer compound.
  • the n-type conductive polymer compound preferably has a polypyridine basic skeleton, and in particular, poly (p-pyridylvinylene). Those having the following basic skeleton are preferred.
  • the film thickness of the charge generation layer 22 is preferably 10 nm or more (particularly 100 nm or more) from the viewpoint of securing the amount of light absorption, and is preferably 1 ⁇ m or less (particularly 300 nm or less) from the viewpoint that the electric resistance does not become too large.
  • the counter electrode 23 is disposed on the opposite side of the surface of the charge generation layer 22 where the electromagnetic wave is incident.
  • the counter electrode 23 can be selected and used from, for example, a general metal electrode such as gold, silver, aluminum, and chromium, or the transparent electrode 21. Small (4.5 eV or less) metals, alloys, electrically conductive compounds and mixtures thereof are preferably used as electrode materials.
  • a buffer layer may be provided between each electrode (transparent electrode 21 and counter electrode 23) sandwiching the charge generation layer 22 so as to act as a buffer zone so that the charge generation layer 22 and these electrodes do not react.
  • the buffer layer include lithium fluoride and poly (3,4-ethylenedioxythiophene), poly (4-styrenesulfonate), 2,9-dimethyl-4,7-diphenyl [1,10] phenanthroline, and the like. Formed using.
  • the image signal output layer 20c performs accumulation of charges obtained by the photoelectric conversion element 20b and output of a signal based on the accumulated charges. Charge for accumulating the charges generated by the photoelectric conversion element 20b for each pixel.
  • the capacitor 24 is a storage element
  • the transistor 25 is an image signal output element that outputs the stored charge as a signal.
  • a TFT Thin Film Transistor
  • This TFT may be an inorganic semiconductor type used in a liquid crystal display or the like or an organic semiconductor, and is preferably a TFT formed on a plastic film.
  • TFTs formed on plastic films amorphous silicon-based TFTs are known, but in addition, FSA (Fluidic Self Assembly) technology developed by Alien Technology in the United States, that is, microfabricated with single crystal silicon.
  • TFTs may be formed on a flexible plastic film by arranging CMOS (Nanoblocks) on an embossed plastic film.
  • CMOS Nemoblocks
  • Science, 283, 822 (1999) and Appl. Phys. It may be a TFT using an organic semiconductor as described in documents such as Lett, 771488 (1998), Nature, 403, 521 (2000).
  • a TFT manufactured by the FSA technique and a TFT using an organic semiconductor are preferable, and a TFT using an organic semiconductor is particularly preferable. If this organic semiconductor is used to form a TFT, equipment such as a vacuum deposition apparatus is not required as in the case where a TFT is formed using silicon, and the TFT can be formed using printing technology or inkjet technology. Is cheaper. Further, since the processing temperature can be lowered, it can be formed on a plastic substrate that is weak against heat.
  • the transistor 25 accumulates electric charges generated in the photoelectric conversion element 20b and is electrically connected to a collecting electrode (not shown) which is one electrode of the capacitor 24.
  • the capacitor 24 accumulates charges generated by the photoelectric conversion element 20 b and reads the accumulated charges by driving the transistor 25. That is, by driving the transistor 25, a signal for each pixel of the radiation image can be output.
  • the substrate 20d functions as a support for the imaging panel 51, and can be made of the same material as the substrate 1.
  • the radiation incident on the radiation image detector 100 is incident from the radiation scintillator panel 10 side of the imaging panel 51 toward the substrate 20d side. Then, the radiation incident on the radiation scintillator panel 10 is absorbed by the scintillator layer 2 in the radiation scintillator panel 10 and emits electromagnetic waves corresponding to the intensity thereof.
  • the electromagnetic waves entering the output substrate 20 pass through the diaphragm 20a and the transparent electrode 21 of the output substrate 20 and reach the charge generation layer 22. Then, the electromagnetic wave is absorbed in the charge generation layer 22 and a hole-electron pair (charge separation state) is formed according to the intensity.
  • the generated electric charges are transported to different electrodes (transparent electrode film and conductive layer) by an internal electric field generated by application of a bias voltage by the power supply unit 54, and a photocurrent flows.
  • the holes carried to the counter electrode 23 side are accumulated in the capacitor 24 of the image signal output layer 20c.
  • the accumulated holes output an image signal when the transistor 25 connected to the capacitor 24 is driven, and the output image signal is stored in the memory unit 53.
  • the photoelectric conversion efficiency can be increased, the SN ratio at the time of low-dose imaging in the radiation image can be improved, and image unevenness and lines can be improved. The generation of noise can be prevented.
  • Example [Production of Substrate] After rolling the A1100-H18 aluminum plate to 0.5 mm and buffing the surface so that the surface of the phosphor-forming surface has the value shown in Table 1, it contains 2% surfactant. It was immersed in a degreasing solution heated to 0 ° C. for 60 seconds and then washed with water for 30 seconds. Next, the substrate was etched with a 10% NaOH aqueous solution heated to 50 ° C. for 30 seconds and then washed with water for 30 seconds. Thereafter, it washed with a 10% NHO 3 aqueous solution for 30 seconds and then washed with water for 30 seconds.
  • the aluminum plate is immersed in an electrolytic solution shown in the electrolysis conditions of Table 1, the substrate is subjected to electrolytic treatment under the conditions of Table 1 using a carbon plate as an anode and a counter electrode, and washed with water for 10 seconds after the treatment. Dry at 100 ° C. for 5 minutes.
  • the anodized film formed on the surface of the aluminum substrate by the above electrolytic treatment was observed with an electron microscope of 100,000 times, and the porosity was calculated by dividing the area of the holes present on the surface by the measurement area.
  • Table 1 shows the measurement results of the porosity, the film thickness of the anodized film, and the 45 ° regular reflectance.
  • Example 9 Further, a polyester film was formed on the substrate of Example 9 by the following procedure.
  • the substrate of Example 10 was not provided with a coating film.
  • a scintillator layer was formed on the aluminum substrate obtained above by the following procedure.
  • a scintillator phosphor (CsI: 0.003Tl) was vapor-deposited on the light absorption layer side of the substrate using the vapor deposition apparatus shown in FIG. 3 to form a scintillator (phosphor) layer.
  • the above-mentioned phosphor raw material was filled in a resistance heating crucible as an evaporation material, and a support was placed on a rotating support holder, and the distance between the support and the evaporation source was adjusted to 400 mm. Subsequently, the inside of the vapor deposition apparatus was once evacuated, Ar gas was introduced and the degree of vacuum was adjusted to 0.5 Pa, and then the substrate temperature was maintained at 150 ° C. while rotating the support at a speed of 10 rpm. Next, the resistance heating crucible was heated to deposit the phosphor, and when the scintillator layer had a thickness of 400 ⁇ m, the deposition was terminated to obtain a scintillator panel (radiation image conversion panel).
  • a scintillator panel radiation image conversion panel
  • ⁇ Brightness evaluation method X-rays with a tube voltage of 70 kVp were irradiated from the back surface of the sample (the surface on which the phosphor layer was not formed), the image data was detected with an FPD provided with a scintillator, and the average signal value of the image was taken as the emission luminance.
  • the measurement results are shown in Table 1 below. However, in Table 1, the value indicating the luminance of the sample is a relative value with the emission luminance of the sample of Comparative Example 1 being 1.0.
  • X-rays with a tube voltage of 80 kVp were irradiated to the radiation incident surface side of the FPD through a lead MTF chart, and image data was detected and recorded on a hard disk. Thereafter, the recording on the hard disk was analyzed by a computer, and the modulation transfer function MTF (MTF value at a spatial frequency of 1 cycle / mm) of the X-ray image recorded on the hard disk was used as an index of sharpness.
  • MTF modulation transfer function

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Abstract

Disclosed is a scintillator panel having excellent luminance and sharpness. The scintillator panel has no possibility of corrosion damage, and can be used for a long time. The scintillator panel is obtained by forming a scintillator layer on a substrate which is composed of aluminum or an aluminum alloy covered with an anodic oxide coating. The scintillator panel is characterized in that the anodic oxide coating is formed by anodizing the surface of the substrate after so planarizing the surface by polishing as to have a maximum roughness depth (Rmax) of not more than 3.0 μm.

Description

シンチレータパネルScintillator panel
　本発明は、輝度及び鮮鋭性に優れ、腐食破損による心配がなく長期間にわたって使用できるシンチレータパネルに関する。 The present invention relates to a scintillator panel that is excellent in brightness and sharpness, can be used over a long period of time without worrying about corrosion damage.
　従来、Ｘ線画像のような放射線画像は医療現場において病状の診断に広く用いられている。特に増感紙－フィルム系による放射線画像は、長い歴史の中で高感度化と高画質化が図られた結果、高い信頼性と優れたコストパフォーマンスを併せ持った撮像システムとして、今なお世界中の医療現場で用いられている。しかしながら、これら画像情報は所謂アナログ画像情報であって、近年発展を続けているデジタル画像情報のような自由な画像処理や瞬時の電送ができない。 Conventionally, radiographic images such as X-ray images have been widely used for diagnosis of medical conditions in the medical field. In particular, radiographic images using intensifying screen-film systems have been developed throughout the world as an imaging system that combines high reliability and excellent cost performance as a result of high sensitivity and high image quality achieved over a long history. Used in medical settings. However, these pieces of image information are so-called analog image information, and free image processing and instantaneous electric transmission such as digital image information that has been developing in recent years cannot be performed.
　そして、近年では、コンピューテッドラジオグラフィ（ＣＲ）やフラットパネル型の放射線デテクタ（ＦＰＤ）等に代表されるデジタル方式の放射線画像検出装置が登場している。これらはデジタルの放射線画像が直接得られ、陰極管や液晶パネル等の画像表示装置に画像を直接表示することが可能なので、必ずしも写真フィルム上への画像形成が必要なものではない。その結果、これらのデジタル方式のＸ線画像検出装置は銀塩写真方式による画像形成の必要性を低減させ、病院や診療所での診断作業の利便性を大幅に向上させている。 In recent years, digital radiographic image detection devices represented by computed radiography (CR), flat panel radiation detectors (FPD) and the like have appeared. Since digital radiographic images are directly obtained and images can be directly displayed on an image display device such as a cathode ray tube or a liquid crystal panel, image formation on a photographic film is not always necessary. As a result, these digital X-ray image detection devices reduce the need for image formation by the silver halide photography method, and greatly improve the convenience of diagnosis work in hospitals and clinics.
　Ｘ線画像のデジタル技術の一つとして、コンピューテッド・ラジオグラフィ（ＣＲ）が現在医療現場で受け入れられている。しかしながら、鮮鋭性が十分でなく空間分解能も不十分であり、スクリーン・フィルムシステムの画質レベルには到達していない。そして、更に新たなデジタルＸ線画像技術として、例えば、雑誌Ｐｈｙｓｉｃｓ　Ｔｏｄａｙ，１９９７年１１月号２４頁のジョン・ローランズ論文“Ａｍｏｒｐｈｏｕｓ　Ｓｅｍｉｃｏｎｄｕｃｔｏｒ　Ｕｓｈｅｒ　ｉｎ　Ｄｉｇｉｔａｌ　Ｘ－ｒａｙ　Ｉｍａｇｉｎｇ”や、雑誌ＳＰＩＥの１９９７年３２巻２頁のエル・イー・アントヌクの論文“Ｄｅｖｅｌｏｐｍｅｎｔ　ｏｆ　ａ　Ｈｉｇｈ　Ｒｅｓｏｌｕｔｉｏｎ，Ａｃｔｉｖｅ　Ｍａｔｒｉｘ，Ｆｌａｔ－Ｐａｎｅｌ　Ｉｍａｇｅｒ　ｗｉｔｈ　Ｅｎｈａｎｃｅｄ　Ｆｉｌｌ　Ｆａｃｔｏｒ”等に記載された、薄膜トランジスタ（ＴＦＴ）を用いた平板Ｘ線検出装置（ＦＰＤ）が開発されている。 As one of the digital technologies for X-ray images, computed radiography (CR) is currently accepted in the medical field. However, the sharpness is insufficient and the spatial resolution is insufficient, and the image quality level of the screen / film system has not been reached. As new digital X-ray imaging techniques, for example, the magazine Physics Today, November 1997, page 24, John Laurans's paper “Amorphous Semiconductor User in Digital X-ray Imaging”, magazine SPIE Vol. 32, 1997. A thin-film transistor (TFT) detection device using a thin-film transistor (TFT) detection device (FFT) using a thin-film transistor (TFT) detection device (TFT), which is described in the L.E. Has been developed.
　放射線を可視光に変換するために、放射線により発光する特性を有するＸ線蛍光体で作られたシンチレータパネルが使用されるが、低線量の撮影においてのＳＮ比を向上するためには、発光効率の高いシンチレータパネルを使用することが必要になってくる。 In order to convert radiation into visible light, a scintillator panel made of an X-ray phosphor having a characteristic of emitting light by radiation is used. In order to improve the S / N ratio in low-dose imaging, luminous efficiency is used. It is necessary to use a high scintillator panel.
　一般にシンチレータパネルの発光効率は、シンチレータの厚さ、蛍光体のＸ線吸収係数によって決まるが、シンチレータの厚さは厚くすればするほどシンチレータ内での発光光の散乱が発生し、鮮鋭性は低下する。そのため、画質に必要な鮮鋭性を決めると膜厚が決定する。 In general, the light emission efficiency of a scintillator panel is determined by the thickness of the scintillator and the X-ray absorption coefficient of the phosphor. The thicker the scintillator, the more the light emitted from the scintillator becomes scattered and the sharpness decreases. To do. Therefore, when the sharpness necessary for the image quality is determined, the film thickness is determined.
　中でも、ヨウ化セシウム（ＣｓＩ）はＸ線から可視光に対する変更率が比較的高く、蒸着によって容易に蛍光体を柱状結晶構造に形成できるため、光ガイド効果により結晶内での発光光の散乱が抑えられ、シンチレータの厚さを厚くすることが可能であった。 Among them, cesium iodide (CsI) has a relatively high rate of change from X-rays to visible light, and phosphors can be easily formed into a columnar crystal structure by vapor deposition. Therefore, it was possible to increase the thickness of the scintillator.
　しかしながら、ＣｓＩのみでは発光効率が低いために、例えば、特公昭５４－３５０６０号公報の如く、ＣｓＩとヨウ化ナトリウム（ＮａＩ）を任意のモル比で混合したものを、蒸着を用いて基板上にナトリウム賦活ヨウ化セシウム（ＣｓＩ：Ｎａ）として堆積、また近年ではＣｓＩとヨウ化タリウム（ＴｌＩ）を任意のモル比で混合したものを、蒸着を用いて基板上にタリウム賦活ヨウ化セシウム（ＣｓＩ：Ｔｌ）として堆積したものに、後工程としてアニールを行うことで可視変換効率を向上させ、Ｘ線蛍光体として使用している。 However, since CsI alone has low luminous efficiency, a mixture of CsI and sodium iodide (NaI) at an arbitrary molar ratio is deposited on the substrate by vapor deposition as disclosed in, for example, Japanese Examined Patent Publication No. 54-3560. Deposited as sodium activated cesium iodide (CsI: Na), and in recent years, a mixture of CsI and thallium iodide (TlI) in an arbitrary molar ratio is deposited on a substrate by vapor deposition using thallium activated cesium iodide (CsI: Visible conversion efficiency is improved by annealing the deposited Tl) as a post process, and it is used as an X-ray phosphor.
　また、他の光出力を増大する手段として、シンチレータを形成する基板を反射性とする方法（例えば特許文献１参照）、基板上に金属反射層を設ける方法（例えば特許文献２参照）、基板上に設けられた反射性金属薄膜と金属薄膜を覆う透明有機膜上にシンチレータを形成する方法（例えば特許文献３参照）などが提案されている。 As another means for increasing the light output, a method for making the substrate on which the scintillator is formed reflective (for example, see Patent Document 1), a method for providing a metal reflective layer on the substrate (for example, Patent Document 2), A method of forming a scintillator on a reflective metal thin film and a transparent organic film covering the metal thin film (see, for example, Patent Document 3) has been proposed.
　気相法によるシンチレータの製造方法としては、アルミ、アモルファスカーボン、ガラスなどの基板上にシンチレータを形成し、その上にシンチレータの表面全体を保護膜で被覆させることが一般的である。更に基板上に設けられた反射性金属薄膜の全体を保護膜で覆い、その保護膜上にシンチレータを堆積させたシンチレータパネルが知られている（例えば特許文献８参照）。 As a manufacturing method of a scintillator by a vapor phase method, it is common to form a scintillator on a substrate such as aluminum, amorphous carbon, or glass, and to cover the entire surface of the scintillator with a protective film. Furthermore, a scintillator panel is known in which the entire reflective metal thin film provided on a substrate is covered with a protective film, and a scintillator is deposited on the protective film (see, for example, Patent Document 8).
　また、ヨウ化セシウム（ＣｓＩ）の柱状結晶状態は、蒸着時の真空度や基板温度などによって制御される。具体的な制御方法が提案されているが（例えば特許文献7参照）、実際のシンチレータ特性は基板のＸ線吸収率、表面性、反射率、表面エネルギー、帯電などの影響が大きく、基板の種類によっては、良好な柱状結晶状態を達成するのが困難であり、特性向上の障害となっている。 Also, the columnar crystal state of cesium iodide (CsI) is controlled by the degree of vacuum during deposition and the substrate temperature. Although a specific control method has been proposed (see, for example, Patent Document 7), the actual scintillator characteristics are greatly affected by the X-ray absorption rate, surface property, reflectance, surface energy, charging, etc. of the substrate. In some cases, it is difficult to achieve a good columnar crystal state, which is an obstacle to improving the characteristics.
　特にアルミ基板は、ガラス基板より破損しにくく、アモルファスカーボン基板に比べて安価であり加工も容易であるメリットがあるが、ヨウ化セシウム（ＣｓＩ）による腐食や、ガラス基板ほど良好な柱状結晶状態が得られないという問題がある。アルミ基板の腐食に関しては、アルミの表面に自然に、形成される保護力の強い酸化皮膜による腐食防止効果に着目し、積極的に陽極酸化皮膜を設けることで腐食を防止する方法（例えば特許文献４、５参照）やアルミの表面をポリマーで被覆する方法（例えば特許文献６参照）またアルミ基板にシンチレータ層を設け基板とＸ線透過性担持体とを結合させる方法（例えば特許文献９参照）なども提案されているが、良好な柱状結晶と耐腐食性向上の両立には課題があった。 In particular, an aluminum substrate is less likely to break than a glass substrate, and has an advantage that it is cheaper and easier to process than an amorphous carbon substrate. However, corrosion due to cesium iodide (CsI), and a columnar crystal state that is better as a glass substrate. There is a problem that it cannot be obtained. Regarding corrosion of aluminum substrates, pay attention to the corrosion prevention effect of oxide films with strong protective power that are formed naturally on the surface of aluminum, and a method of preventing corrosion by actively providing an anodic oxide film (for example, patent document) 4 and 5), a method of coating the surface of aluminum with a polymer (see, for example, Patent Document 6), and a method in which a scintillator layer is provided on an aluminum substrate to bond the substrate and an X-ray transparent carrier (see, for example, Patent Document 9). However, there has been a problem in achieving both good columnar crystals and improved corrosion resistance.
　このような状況から、良好な柱状性を有し、輝度や鮮鋭性に優れ長期間にわたって腐食による特性の低下のないアルミ基板を開発することが望まれている。
特公平７－２１５６０号公報 特公平１－２４０８８７号公報 特開２０００－３５６６７９号公報 特開２００５－４９３４１号公報 特開２００６－１１３００７号公報 特開２００６－１３８６４２号公報 特開２００７－２９２７５５号公報 特開２００１－２８９９５２号公報 特開２００８－５１８１４号公報 Under such circumstances, it is desired to develop an aluminum substrate that has good columnarity, excellent brightness and sharpness, and does not deteriorate characteristics due to corrosion over a long period of time.
Japanese Patent Publication No. 7-21560 Japanese Patent Publication No. 1-240887 JP 2000-356679 A JP 2005-49341 A JP 2006-113007 A JP 2006-138642 A JP 2007-292755 A JP 2001-289952 A JP 2008-51814 A
　本発明は、上記問題・状況に鑑みてなされたものであり、その解決課題は、輝度及び鮮鋭性に優れ、腐食破損による心配がなく長期間にわたって使用できるシンチレータパネルを提供することである。 The present invention has been made in view of the above-mentioned problems and situations, and a problem to be solved is to provide a scintillator panel that is excellent in luminance and sharpness, can be used for a long period of time without fear of corrosion damage.
　本発明者らは、上記課題を解決すべく鋭意検討を加えた結果、陽極酸化処理後のアルミ基板の平滑性ではなく、陽極酸化処理する前のアルミ基板の研磨状態が、柱状結晶成長に大きく影響を与えていることを見出し、さらに、この知見に基づき良好な柱状結晶状態にすることにより、シンチレータパネルの鮮鋭性等の性能を向上させることができることを見出し、本発明に至った。 As a result of intensive studies to solve the above problems, the present inventors have found that the polished state of the aluminum substrate before the anodizing treatment, rather than the smoothness of the aluminum substrate after the anodizing treatment, greatly increases the columnar crystal growth. It has been found that it has an influence, and furthermore, it has been found that by making a good columnar crystal state based on this knowledge, performance such as the sharpness of the scintillator panel can be improved, and the present invention has been achieved.
　すなわち、本発明に係る上記課題は、以下の手段により解決される。 That is, the above-mentioned problem according to the present invention is solved by the following means.
　１．陽極酸化皮膜で被覆されたアルミニウム又はアルミニウム合金からなる基板上にシンチレータ層を設けて成るシンチレータパネルであって、当該陽極酸化皮膜が、当該基板の表面を、研磨により表面粗度が最大高さ（Ｒｍａｘ）で３．０μｍ以下になるように平坦化した後に、陽極酸化処理することで形成されたことを特徴とするシンチレータパネル。 1. A scintillator panel in which a scintillator layer is provided on a substrate made of aluminum or an aluminum alloy coated with an anodized film, wherein the anodized film has a maximum surface roughness by polishing the surface of the substrate ( A scintillator panel formed by anodizing after flattening to Rmax) of 3.0 μm or less.
　２．前記基板のシンチレータ層が形成される側の表面における、入射角４５°での可視光の正反射率が、６０％以上であることを特徴とする前記１に記載のシンチレータパネル。 2. 2. The scintillator panel according to 1 above, wherein the regular reflectance of visible light at an incident angle of 45 ° on the surface of the substrate on which the scintillator layer is formed is 60% or more.
　３．前記基板の角部が、曲率半径Ｒの円弧状となるように加工されていることを特徴とする前記１又は２に記載のシンチレータパネル。 3. 3. The scintillator panel according to 1 or 2, wherein the corner portion of the substrate is processed so as to have an arc shape with a curvature radius R.
　４．前記曲率半径Ｒの範囲が、１～１０ｍｍであることを特徴とする前記３に記載のシンチレータパネル。 4. 4. The scintillator panel according to 3 above, wherein the radius of curvature R is 1 to 10 mm.
　５．前記基板の少なくともシンチレータ層が形成される側の表面が、樹脂で被覆されていることを特徴とする前記１から４のいずれか一項に記載のシンチレータパネル。 5. 5. The scintillator panel according to claim 1, wherein at least a surface of the substrate on which the scintillator layer is formed is coated with a resin.
　６．前記樹脂が、ポリエステルを含む樹脂であることを特徴であることを特徴とする前記５に記載のシンチレータパネル。 6. 6. The scintillator panel according to 5, wherein the resin is a resin containing polyester.
　７．前記樹脂による被覆が、ＣＶＤ法により基板全面に形成されたポリパラキシリレン膜による被覆であることを特徴とする前記５に記載のシンチレータパネル。 7. 6. The scintillator panel according to 5 above, wherein the coating with the resin is a coating with a polyparaxylylene film formed on the entire surface of the substrate by a CVD method.
　８．前記基板の陽極酸化皮膜の有穴率が、６０％以下であることを特徴とする前記１から７のいずれか一項に記載のシンチレータパネル。 8. The scintillator panel according to any one of 1 to 7, wherein a hole ratio of the anodized film on the substrate is 60% or less.
　９．前記陽極酸化皮膜の厚さが、２００～２０００ｎｍであることを特徴とする前記１から８のいずれか一項に記載のシンチレータパネル。 9. 9. The scintillator panel according to any one of 1 to 8, wherein the anodized film has a thickness of 200 to 2000 nm.
　１０．前記シンチレータ層が、ヨウ化セシウムと少なくとも１種類以上のタリウム化合物を含む添加剤を原材料として気相法にて形成されたことを特徴とする前記１から９のいずれか一項に記載のシンチレータパネル。 10. The scintillator panel according to any one of 1 to 9, wherein the scintillator layer is formed by a vapor phase method using an additive containing cesium iodide and at least one kind of thallium compound as a raw material. .
　１１．シンチレータパネル全面を覆う樹脂からなる保護膜を有することを特徴とする前記１から１０のいずれか一項に記載のシンチレータパネル。 11. The scintillator panel according to any one of 1 to 10, further comprising a protective film made of a resin covering the entire surface of the scintillator panel.
　１２．前記保護膜として、ＣＶＤ法により形成されたポリパラキシリレン膜を有することを特徴とする前記１１に記載のシンチレータパネル。 12. 12. The scintillator panel according to 11, wherein the protective film includes a polyparaxylylene film formed by a CVD method.
　本発明の上記手段により、輝度及び鮮鋭性に優れ、腐食破損による心配がなく長期間にわたって使用できるシンチレータパネルを提供することができる。 By the above means of the present invention, it is possible to provide a scintillator panel that is excellent in brightness and sharpness, can be used for a long period of time without fear of corrosion damage.
放射線用シンチレータパネル１０の概略構成を示す断面図Sectional drawing which shows schematic structure of scintillator panel 10 for radiation 放射線用シンチレータパネル１０の拡大断面図Expanded sectional view of radiation scintillator panel 10 蒸着装置６１の概略構成を示す図The figure which shows schematic structure of the vapor deposition apparatus 61 放射線画像検出器１００の概略構成を示す一部破断斜視図Partially broken perspective view showing a schematic configuration of the radiation image detector 100 撮像パネル５１の拡大断面図Enlarged sectional view of the imaging panel 51
符号の説明Explanation of symbols
　１　基板
　２　シンチレータ（蛍光体）層
　３　反射層
　４　保護層
　１０　放射線用シンチレータパネル
　６１　蒸着装置
　６２　真空容器
　６３　ボート（被充填部材）
　６４　ホルダ
　６５　回転機構
　６６　真空ポンプ
　１００　放射線画像検出器 DESCRIPTION OF SYMBOLS 1 Substrate 2 Scintillator (phosphor) layer 3 Reflective layer 4 Protective layer 10 Radiation scintillator panel 61 Deposition apparatus 62 Vacuum vessel 63 Boat (filled member)
64 Holder 65 Rotating mechanism 66 Vacuum pump 100 Radiation image detector
　本発明のシンチレータパネルは、陽極酸化皮膜で被覆されたアルミニウム又はアルミニウム合金からなる基板上にシンチレータ層を設けて成るシンチレータパネルであって、当該陽極酸化皮膜が、当該基板の表面を、研磨により表面粗度が最大高さ（Ｒｍａｘ）で３．０μｍ以下になるように平坦化した後に、陽極酸化処理することで形成されたことを特徴とする。この特徴は、請求の範囲第１項から第１２項に係る発明に共通する技術的特徴である。 The scintillator panel of the present invention is a scintillator panel in which a scintillator layer is provided on a substrate made of aluminum or an aluminum alloy coated with an anodized film, and the anodized film is polished by polishing the surface of the substrate. It is characterized in that it is formed by anodizing after flattening so that the roughness is 3.0 μm or less at the maximum height (Rmax). This feature is a technical feature common to the inventions according to claims 1 to 12.
　本発明の実施態様としては、上記課題解決の観点から、前記基板のシンチレータ層が形成される側の表面における、入射角４５°での可視光の正反射率が、６０％以上である態様が好ましい。また、前記基板の角部が、曲率半径Ｒの円弧状となるように加工されていることが好ましい。さらに、当該曲率半径Ｒの範囲が、１～１０ｍｍであることが好ましい。 As an embodiment of the present invention, from the viewpoint of solving the above problem, an aspect in which the regular reflectance of visible light at an incident angle of 45 ° on the surface of the substrate on the side where the scintillator layer is formed is 60% or more. preferable. Moreover, it is preferable that the corner portion of the substrate is processed so as to have an arc shape with a curvature radius R. Further, the range of the curvature radius R is preferably 1 to 10 mm.
　また、本発明においては、前記基板の少なくともシンチレータ層が形成される側の表面が、樹脂で被覆されている態様が好ましい。また、当該樹脂が、ポリエステルを含む樹脂であること、或いは、当該樹脂による被覆が、ＣＶＤ法（Ｃｈｅｍｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ；「化学蒸着法」ともいう。）により基板全面に形成されたポリパラキシリレン膜による被覆であることが好ましい。 In the present invention, it is preferable that at least the surface of the substrate on which the scintillator layer is formed is coated with a resin. In addition, the resin is a resin containing polyester, or a polyparaxylene film in which the coating with the resin is formed on the entire surface of the substrate by a CVD method (Chemical Vapor Deposition; also referred to as “chemical vapor deposition method”). It is preferable that the coating is.
　本発明においては、前記基板の陽極酸化皮膜の有穴率が、６０％以下である態様であることが好ましい。また、当該陽極酸化皮膜の厚さが、２００～２０００ｎｍであることが好ましい。 In the present invention, it is preferable that the porosity of the anodic oxide film on the substrate is 60% or less. The thickness of the anodic oxide film is preferably 200 to 2000 nm.
　また、本発明においては、前記シンチレータ層が、ヨウ化セシウムと少なくとも１種類以上のタリウム化合物を含む添加剤を原材料として気相法にて形成されることが好ましい。 In the present invention, the scintillator layer is preferably formed by a vapor phase method using an additive containing cesium iodide and at least one thallium compound as a raw material.
　さらに、本発明のシンチレータパネルは、シンチレータパネル全面を覆う樹脂からなる保護膜を有する態様であることが好ましい。当該保護膜として、ＣＶＤ法により形成されたポリパラキシリレン膜を有する態様であることが好ましい。 Furthermore, it is preferable that the scintillator panel of the present invention has a protective film made of resin that covers the entire surface of the scintillator panel. It is preferable that the protective film has a polyparaxylylene film formed by a CVD method.
　以下、本発明とその構成要素、及び本発明を実施するための最良の形態・態様についてさらに詳細な説明をする。 Hereinafter, the present invention, its constituent elements, and the best mode and mode for carrying out the present invention will be described in further detail.
　（本発明のシンチレータパネルの特徴）
　本発明のシンチレータパネルは、陽極酸化皮膜で被覆されたアルミニウム又はアルミニウム合金からなる基板上にシンチレータ層を設けて成るシンチレータパネルでるが、当該陽極酸化皮膜が、当該基板の表面を、研磨により表面粗度が最大高さ（Ｒｍａｘ）で３．０μｍ以下になるように平坦化した後に、陽極酸化処理することで形成されたことを特徴とする。なお、最大高さ（Ｒｍａｘ）は、１．５μｍ以下であることが輝度特性を向上させる上で好ましく、０．０１～１．５μｍであることがより好ましい。 (Features of the scintillator panel of the present invention)
The scintillator panel of the present invention is a scintillator panel in which a scintillator layer is provided on a substrate made of aluminum or an aluminum alloy coated with an anodized film. The anodized film is a surface roughened by polishing. It is characterized in that it is formed by anodizing after flattening so that the degree is 3.0 μm or less at the maximum height (Rmax). The maximum height (Rmax) is preferably 1.5 μm or less from the viewpoint of improving luminance characteristics, and more preferably 0.01 to 1.5 μm.
　ここで、アルミニウム又はアルミニウム合金からなる基板の研磨傷、スジなどがシンチレータパネルの鮮鋭性に与える影響は、ＪＩＳ　Ｂ０６０１（１９８２）で定義されているＲｍａｘ、Ｒｚで好適に評価できる。なお、表面性状の平均である中心線平均粗さＲａ、及び陽極酸化処理後の評価では、本発明の効果は得られない。 Here, the influence of polishing scratches, streaks, etc. on the substrate made of aluminum or aluminum alloy on the sharpness of the scintillator panel can be suitably evaluated by Rmax and Rz defined in JIS B0601 (1982). In addition, the effect of this invention is not acquired in the evaluation after centerline average roughness Ra which is an average of surface property, and an anodizing process.
　本発明者らは、陽極酸化処理後のアルミ基板の入射角４５°の正反射率が、シンチレータパネルの輝度に寄与が大きいことも見出した。拡散反射成分も、シンチレータパネルの輝度向上に寄与するが、鮮鋭性（ＭＴＦ）の低下を伴い、本発明の効果は得られない。 The present inventors have also found that the regular reflectance at an incident angle of 45 ° of the aluminum substrate after the anodizing treatment greatly contributes to the brightness of the scintillator panel. Although the diffuse reflection component also contributes to the improvement of the brightness of the scintillator panel, the sharpness (MTF) is lowered and the effect of the present invention cannot be obtained.
　本願において、「正反射率」とは、物体の表面に一定の角度から入射した光に対する、同様の角度で反射する光の割合であり、「入射角４５°での正反射率」とは、入射角が基板に対し４５°となっている場合の反射率をいう。一般には、正反射率が高い物体の表面は、人間の目にはほぼ鏡面として認識されることが知られている。 In the present application, “regular reflectance” is a ratio of light reflected at the same angle to light incident on the surface of the object from a certain angle, and “regular reflectance at an incident angle of 45 °” The reflectance when the incident angle is 45 ° with respect to the substrate. In general, it is known that the surface of an object having a high regular reflectance is recognized as a mirror surface by the human eye.
　本発明者らは、さらに検討を進めるなかで、陽極酸化皮膜の腐食防止効果は有穴率が６０％以下であること、また、陽極極酸化皮膜の厚さが２００～２０００ｎｍであることで腐食防止効果が大となることを見出した。 As the inventors further studied, the corrosion prevention effect of the anodic oxide film is that the porosity is 60% or less, and the thickness of the anodic oxide film is 200 to 2000 nm. It has been found that the prevention effect is significant.
　また、ヨウ化セシウム（ＣｓＩ）には強い腐食性があり、陽極酸化皮膜の表面をさらに樹脂（ポリマー）で被覆することが好ましい。これにより基板の耐腐食性はより向上する。基板を被覆する樹脂としては、陽極酸化皮膜とヨウ化セシウムを絶縁するものであれば、本発明の効果は得られるが、加工性を考慮すると、ポリエステルを含む樹脂、又はＣＶＤ法により基板全面に形成されたポリパラキシリレンを含む樹脂であることが好ましい。 Also, cesium iodide (CsI) has strong corrosive properties, and it is preferable to further coat the surface of the anodized film with a resin (polymer). This further improves the corrosion resistance of the substrate. As the resin for covering the substrate, the effect of the present invention can be obtained as long as the anodized film and cesium iodide are insulated. However, in consideration of workability, the resin is coated on the entire surface of the substrate by a resin containing polyester or CVD. A resin containing the formed polyparaxylylene is preferable.
　本発明のシンチレータパネルを光電変換素子とカップリングするにあたっては、光電変換素子とシンチレータの位置合わせが必要となる。この場合、基板の角部が鋭利であると、光電変換素子にダメージを与える場合がある。本発明では、基板の角部が、曲率半径Ｒの円弧状となるように加工されていること好ましい。曲率半径Ｒは、光電変換素子のダメージを軽減できればよく形状は特に限定されず、直線カット（Ｒ＝∞）でもかまわない。特に好ましくは、加工作業性から曲率半径Ｒの範囲が１～１０ｍｍである。 In coupling the scintillator panel of the present invention with a photoelectric conversion element, it is necessary to align the photoelectric conversion element and the scintillator. In this case, if the corner portion of the substrate is sharp, the photoelectric conversion element may be damaged. In the present invention, it is preferable that the corner portion of the substrate is processed so as to have an arc shape with a curvature radius R. The curvature radius R is not particularly limited as long as the damage to the photoelectric conversion element can be reduced, and a straight cut (R = ∞) may be used. Particularly preferably, the radius of curvature R is 1 to 10 mm from the viewpoint of workability.
　（基板）
　陽極酸化皮膜で被覆されたアルミニウム又はアルミニウム合金基板は、陽極酸化皮膜が、アルミニウム又はアルミニウム合金の表面を、研磨により表面粗度が最大高さ（Ｒｍａｘ）で３．０μｍ以下になるように平坦化した後、陽極酸化処理することで形成されたことを特徴とする。また、基板の角部を曲率半径Ｒの円弧状となるように加工しておくことで、シンチレータパネル張り合わせ時の光電変換素子のダメージが軽減される。 (substrate)
An aluminum or aluminum alloy substrate coated with an anodized film is flattened so that the surface of the aluminum or aluminum alloy is polished to have a maximum surface roughness (Rmax) of 3.0 μm or less by polishing. Then, it is formed by anodizing treatment. Further, by processing the corners of the substrate so as to have an arc shape with a radius of curvature R, damage to the photoelectric conversion elements when the scintillator panels are bonded is reduced.
　陽極酸化されたアルミニウム等からなる基板を作るためには、硫酸、燐酸、シュウ酸、クロム酸又はスルファミド酸、ベンゼンスルホン酸の如き有機酸、又はそれらの混合物を含有する溶液に陽極として浸漬されたアルミニウム板に電流を流す。１～７０質量％の電解質濃度は、０～７０℃の範囲の温度で、より好ましくは３５～６０℃の範囲の温度で使用されることができる。 In order to make a substrate made of anodized aluminum or the like, it was immersed as an anode in a solution containing sulfuric acid, phosphoric acid, oxalic acid, chromic acid or sulfamic acid, an organic acid such as benzenesulfonic acid, or a mixture thereof. Current is passed through the aluminum plate. An electrolyte concentration of 1 to 70% by weight can be used at a temperature in the range of 0 to 70 ° C, more preferably at a temperature in the range of 35 to 60 ° C.
　陽極電流密度は、１～５０Ａ／ｄｍを変化してもよく、また１～１００Ｖの範囲の電圧を変化して１～８ｇ／ｍ２　Ａｌ２Ｏ３・Ｈ２Ｏの陽極酸化フィルムを得てもよい。陽極酸化されたアルミニウム板は続いて１０～８０℃の範囲の温度の脱イオン水でリンスされてもよい。 The anode current density, 1 ~ 50A / dm may be changed, also give an anodic oxidation film of 1 ~ 8g / m 2 Al 2 O 3 · H 2 O by changing the voltage in the range of 1 ~ 100 V Also good. The anodized aluminum plate may subsequently be rinsed with deionized water at a temperature in the range of 10-80 ° C.
　陽極酸化工程後、後処理、例えば封止を陽極表面に適用してもよい。陽極酸化によって形成された酸化アルミニウム層の孔の封止はアルミニウム陽極酸化の技術分野で公知の技術である。この技術は例えば“Ｂｅｌｇｉｓｃｈ－Ｎｅｄｅｒｌａｎｄｓ　ｔｉｊｄｓｃｈｒｉｆｔ　ｖｏｏｒ　Ｏｐｐｅｒｖｌａｋｔｅｔｅｃｈｎｉｅｋｅｎ　ｖａｎ　ｍａｔｅｒｉａｌｅｎ”（表面技術及び材料の道程）、Ｖｏｌｕｍｅ２４，１９８０年１月、名称“Ｓｅａｌｉｎｇ－ｋｗａｌｉｔｅｉｔ　ｅｎ　ｓｅａｌｉｎｇ－ｃｏｎｔｒｏｌｅ　ｖａｎ　ｇｅａｎｏｄｉｓｅｅｒｄ　Ａｌｕｍｉｎｕｍ”（陽極酸化されたアルミニウムの封止品質及び封止制御）に記載されている。 After the anodizing step, post-treatment such as sealing may be applied to the anode surface. Sealing the holes in the aluminum oxide layer formed by anodization is a well-known technique in the technical field of aluminum anodization. This technology is, for example, “Belgsch-Nederlands tijdschiff voor Uppervlacktechtechniken van materialen” (surface technology and material process), Volume 24, January 1980, name “Sealing-kalliteminte-alumine-oxidant-alumino-oxidant-alumine-oxidant-alumino-oxidant-alumino-oxidant Sealing quality and sealing control).
　（金属反射層）
　本発明では、光出力を増大するため、基板上に別途金属反射層を設けることも可能であるが、陽極酸化皮膜の入射角４５°での可視光の正反射率を６０％以上にしておくことで金属反射層なしで光出力が増大する効果が得られる。 (Metal reflective layer)
In the present invention, a metal reflective layer can be separately provided on the substrate in order to increase the light output, but the regular reflectance of visible light at an incident angle of 45 ° of the anodized film is set to 60% or more. As a result, the effect of increasing the light output without the metal reflection layer can be obtained.
　本発明において、基板上に別途金属反射層を設ける場合は、発光光の利用効率の面で金属反射層は反射率の高い金属で形成することが好ましい。反射率の高い金属膜層としては、Ａｌ、Ａｇ、Ｃｒ、Ｃｕ、Ｎｉ、Ｍｇ、Ｐｔ、Ａｕからなる群の中の物質を含む材料が挙げられる。また、このような金属薄膜を２層以上形成するようにしても良い。金属薄膜を２層以上とする場合は、下層を、Ｃｒを含む層とすることが基板との接着性を向上させる点から好ましい。また、金属薄膜上にＳｉＯ２、ＴｉＯ２等の金属酸化物からなる層をこの順に設けてさらに反射率を向上させても良い。 In the present invention, when a metal reflective layer is separately provided on the substrate, it is preferable that the metal reflective layer is formed of a metal having a high reflectance in terms of utilization efficiency of emitted light. Examples of the metal film layer having high reflectivity include a material containing a substance in the group consisting of Al, Ag, Cr, Cu, Ni, Mg, Pt, and Au. Two or more such metal thin films may be formed. When the metal thin film has two or more layers, the lower layer is preferably a layer containing Cr from the viewpoint of improving the adhesion to the substrate. Further, a layer made of a metal oxide such as SiO 2 or TiO 2 may be provided in this order on the metal thin film to further improve the reflectance.
　（シンチレータ）
　本発明に係る「シンチレータ」とは、Ｘ線等の入射された放射線のエネルギーを吸収して、波長が３００ｎｍから８００ｎｍの電磁波、即ち可視光線を中心の電磁波（光）を発光する蛍光体をいう。 (Scintillator)
The “scintillator” according to the present invention refers to a phosphor that absorbs energy of incident radiation such as X-rays and emits electromagnetic waves having a wavelength of 300 nm to 800 nm, that is, electromagnetic waves (light) centered on visible light. .
　シンチレータを形成する材料としては、種々の公知の蛍光体材料を使用することができるが、Ｘ線から可視光に対する変更率が比較的高く、蒸着によって容易に蛍光体を柱状結晶構造に形成できるため、光ガイド効果により結晶内での発光光の散乱が抑えられ、シンチレータ層の厚さを厚くすることが可能であることからヨウ化セシウム（ＣｓＩ）が好ましい。 As a material for forming the scintillator, various known phosphor materials can be used. However, the rate of change from X-ray to visible light is relatively high, and the phosphor can be easily formed into a columnar crystal structure by vapor deposition. Cesium iodide (CsI) is preferable because scattering of the emitted light in the crystal can be suppressed by the light guide effect and the thickness of the scintillator layer can be increased.
　但し、ＣｓＩのみでは発光効率が低いために、各種の賦活剤が添加される。例えば、特公昭５４－３５０６０号公報の如く、ＣｓＩとヨウ化ナトリウム（ＮａＩ）を任意のモル比で混合したものが挙げられる。また、例えば、特開２００１－５９８９９号公報に開示されているような、ＣｓＩを蒸着でインジウム（Ｉｎ）、タリウム（Ｔｌ）、リチウム（Ｌｉ）、カリウム（Ｋ）、ルビジウム（Ｒｂ）、ナトリウム（Ｎａ）などの賦活物質を含有するＣｓＩが好ましい。 However, since CsI alone has low luminous efficiency, various activators are added. For example, as disclosed in Japanese Examined Patent Publication No. 54-35060, a mixture of CsI and sodium iodide (NaI) in an arbitrary molar ratio can be mentioned. Further, for example, as disclosed in JP-A-2001-59899, CsI is deposited by vapor deposition of indium (In), thallium (Tl), lithium (Li), potassium (K), rubidium (Rb), sodium ( CsI containing an activating substance such as Na) is preferred.
　なお、本発明においては、特に１種類以上のタリウム化合物を含む添加剤とヨウ化セシウムとを原材料とすることが好ましい。即ち、タリウム賦活ヨウ化セシウム（ＣｓＩ：Ｔｌ）は４００ｎｍから７５０ｎｍまでの広い発光波長を持つことから好ましい。 In the present invention, it is particularly preferable to use an additive containing one or more thallium compounds and cesium iodide as raw materials. That is, thallium activated cesium iodide (CsI: Tl) is preferable because it has a broad emission wavelength from 400 nm to 750 nm.
　本発明に係る１種類以上のタリウム化合物を含有する添加剤のタリウム化合物としては、種々のタリウム化合物（＋Ｉと＋IIIの酸化数の化合物）を使用することができる。本発明において、好ましいタリウム化合物は臭化タリウム（ＴｌＢｒ）、塩化タリウム（ＴｌＣｌ）またはフッ化タリウム（ＴｌＦ、ＴｌＦ３）等である。 As the thallium compound as an additive containing one or more types of thallium compounds according to the present invention, various thallium compounds (compounds having oxidation numbers of + I and + III) can be used. In the present invention, preferred thallium compounds are thallium bromide (TlBr), thallium chloride (TlCl), thallium fluoride (TlF, TlF 3 ), and the like.
　また、本発明に係るタリウム化合物の融点は４００～７００℃の範囲内にあることが好ましい。７００℃以内を超えると柱状結晶内での添加剤が不均一に存在してしまい、発光効率が低下する。なお、本発明での融点とは常温常圧下における融点である。また、タリウム化合物の分子量は２０６～３００の範囲内にあることが好ましい。 The melting point of the thallium compound according to the present invention is preferably in the range of 400 to 700 ° C. If the temperature exceeds 700 ° C., the additive in the columnar crystals exists non-uniformly, and the luminous efficiency is lowered. In the present invention, the melting point is a melting point at normal temperature and pressure. The molecular weight of the thallium compound is preferably in the range of 206 to 300.
　本発明に係るシンチレータにおいて、当該添加剤の含有量は目的性能等に応じて最適量にすることが望ましいが、ヨウ化セシウムの含有量に対して０．００１～５０ｍｏｌ％、更に０．１～１０．０ｍｏｌ％であることが好ましい。 In the scintillator according to the present invention, the content of the additive is desirably an optimum amount according to the target performance and the like, but is 0.001 to 50 mol% with respect to the content of cesium iodide, and further 0.1 to It is preferable that it is 10.0 mol%.
　ここで、ヨウ化セシウムに対し添加剤が０．００１ｍｏｌ％未満であると、ヨウ化セシウム単独使用で得られる発光輝度と大差なく、目的とする発光輝度を得ることができない。また、５０ｍｏｌ％を超えると、ヨウ化セシウムの性質、機能を保持することができない。なお、シンチレータ層の厚さは、１００～８００μｍであることが好ましく、１２０～７００μｍであることが、輝度と鮮鋭性の特性をバランスよく得られることより好ましい。 Here, if the additive is less than 0.001 mol% with respect to cesium iodide, the target light emission luminance cannot be obtained without much difference from the light emission luminance obtained by using cesium iodide alone. Moreover, when it exceeds 50 mol%, the property and function of cesium iodide cannot be maintained. Note that the thickness of the scintillator layer is preferably 100 to 800 μm, and more preferably 120 to 700 μm, from the viewpoint of obtaining a good balance between luminance and sharpness characteristics.
　（被覆用樹脂）
　少なくとも基板のシンチレータ層形成面側を被覆する樹脂としては、スピンコータやワイヤーバーでの加工が容易なポリエステルを含む樹脂、またはＣＶＤ法（Ｃｈｅｍｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ；「化学蒸着法」とも言われる。）により容易に基板全面に被覆できるポリパラキシリレン膜が好適である。 (Resin for coating)
As a resin that covers at least the scintillator layer forming surface side of the substrate, a resin containing polyester that can be easily processed with a spin coater or a wire bar, or a CVD method (Chemical Vapor Deposition; also referred to as “chemical vapor deposition method”) is easy. A polyparaxylylene film that can be coated on the entire surface of the substrate is suitable.
　（保護膜）
　本発明のシンチレータパネルは、その全面を覆う樹脂からなる保護膜を有することを特徴とする。 (Protective film)
The scintillator panel of the present invention is characterized by having a protective film made of resin covering the entire surface.
　保護膜は、シンチレータ層を防湿し、シンチレータ層の劣化を抑制するためのもので、透湿度の低い物質から構成される。例えば、保護膜として、ポリエチレンテレフタレートフィルム（ＰＥＴ）を用いることができる。ＰＥＴの他には、ポリエステルフィルム、ポリメタクリレートフィルム、ニトロセルロースフィルム、セルロースアセテートフィルム、ポリプロピレンフィルム、ポリエチレンナフタレートフィルム等を用いることができる。また、ポリパラキシリレン（１０～１４Ｓ／ｃｍ）は、ＣＶＤ法により容易にシンチレータパネルの全面にポリパラキシリレン膜を形成することが可能であるため、本発明においては好適である。 The protective film is for moisture-proofing the scintillator layer and suppressing deterioration of the scintillator layer, and is made of a material having low moisture permeability. For example, a polyethylene terephthalate film (PET) can be used as the protective film. Besides PET, a polyester film, a polymethacrylate film, a nitrocellulose film, a cellulose acetate film, a polypropylene film, a polyethylene naphthalate film, or the like can be used. Polyparaxylylene (10 to 14 S / cm) is suitable in the present invention because a polyparaxylylene film can be easily formed on the entire surface of the scintillator panel by the CVD method.
　（シンチレータパネルの作製方法）
　本発明のシンチレータパネルの作製方法の典型的例について、図を参照しながら説明する。なお、図１は、放射線用シンチレータパネル１０の概略構成を示す断面図である。図２は、放射線用シンチレータパネル１０の拡大断面図である。図３は、蒸着装置６１の概略構成を示す図面である。 (Production method of scintillator panel)
A typical example of a method for manufacturing a scintillator panel of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of the radiation scintillator panel 10. FIG. 2 is an enlarged cross-sectional view of the radiation scintillator panel 10. FIG. 3 is a diagram showing a schematic configuration of the vapor deposition apparatus 61.
　〈蒸着装置〉
　図３に示す通り、蒸着装置６１は箱状の真空容器６２を有しており、真空容器６２の内部には真空蒸着用のボート６３が配されている。ボート６３は蒸着源の被充填部材であり、当該ボート６３には電極が接続されている。当該電極を通じてボート６３に電流が流れると、ボート６３がジュール熱で発熱するようになっている。 <Vapor deposition equipment>
As shown in FIG. 3, the vapor deposition apparatus 61 has a box-shaped vacuum vessel 62, and a vacuum vapor deposition boat 63 is disposed inside the vacuum vessel 62. The boat 63 is a member to be filled as an evaporation source, and an electrode is connected to the boat 63. When a current flows through the electrode to the boat 63, the boat 63 generates heat due to Joule heat.
　放射線用シンチレータパネル１０の製造時においては、ヨウ化セシウムと賦活剤化合物とを含む混合物がボート６３に充填され、そのボート６３に電流が流れることで上記混合物を加熱・蒸発させることができるようになっている。なお、被充填部材として、ヒータを巻回したアルミナ製のルツボを適用してもよいし、高融点金属製のヒータを適用してもよい。 At the time of manufacturing the radiation scintillator panel 10, the boat 63 is filled with a mixture containing cesium iodide and an activator compound, and an electric current flows through the boat 63 so that the mixture can be heated and evaporated. It has become. An alumina crucible around which a heater is wound may be applied as the member to be filled, or a refractory metal heater may be applied.
　真空容器６２の内部であってボート６３の直上には、基板１を保持するホルダ６４が配されている。ホルダ６４にはヒータ（図示略）が配されており、当該ヒータを作動させることで、ホルダ６４に装着した基板１を加熱することができるようになっている。 A holder 64 for holding the substrate 1 is disposed inside the vacuum vessel 62 and directly above the boat 63. The holder 64 is provided with a heater (not shown), and the substrate 1 mounted on the holder 64 can be heated by operating the heater.
　基板１を加熱した場合には、基板１の表面の吸着物を離脱、除去したり、基板１とその表面に形成されるシンチレータ層（蛍光体層）２との間に不純物層が形成されるのを防止したり、基板１とその表面に形成されるシンチレータ層２との密着性を強化したり、基板１の表面に形成されるシンチレータ層２の膜質の調整を行ったりすることができるようになっている。 When the substrate 1 is heated, the adsorbate on the surface of the substrate 1 is removed and removed, or an impurity layer is formed between the substrate 1 and the scintillator layer (phosphor layer) 2 formed on the surface. Can be prevented, the adhesion between the substrate 1 and the scintillator layer 2 formed on the surface thereof can be enhanced, or the film quality of the scintillator layer 2 formed on the surface of the substrate 1 can be adjusted. It has become.
　ホルダ６４には、当該ホルダ６４を回転させる回転機構６５が配されている。回転機構６５は、ホルダ６４に接続された回転軸６５ａとその駆動源となるモータ（図示略）から構成されたもので、当該モータを駆動させると、回転軸６５ａが回転してホルダ６４をボート６３に対向させた状態で回転させることができるようになっている。 The holder 64 is provided with a rotation mechanism 65 that rotates the holder 64. The rotating mechanism 65 is composed of a rotating shaft 65a connected to the holder 64 and a motor (not shown) as a driving source for the rotating shaft 65. When the motor is driven, the rotating shaft 65a rotates to displace the holder 64 in the boat. It can be rotated in a state of being opposed to 63.
　蒸着装置６１では、上記構成の他に真空容器６２に真空ポンプ６６が配されている。真空ポンプ６６は、真空容器６２の内部の排気と真空容器６２の内部へのガスの導入とを行うもので、当該真空ポンプ６６を作動させることにより、真空容器６２の内部を一定圧力のガス雰囲気下に維持することができるようになっている。 In the vapor deposition apparatus 61, a vacuum pump 66 is disposed in a vacuum vessel 62 in addition to the above configuration. The vacuum pump 66 exhausts the inside of the vacuum container 62 and introduces gas into the vacuum container 62. By operating the vacuum pump 66, the inside of the vacuum container 62 has a gas atmosphere at a constant pressure. Can be maintained below.
　〈シンチレータパネル〉
　次に、本発明に係るシンチレータパネル１０の作製方法について説明する。 <Scintillator panel>
Next, a method for manufacturing the scintillator panel 10 according to the present invention will be described.
　当該放射線用シンチレータパネル１０の作製方法においては、上記で説明した蒸発装置６１を好適に用いることができる。蒸発装置６１を用いて放射線用シンチレータパネル１０を作製する方法について説明する。 In the method for producing the radiation scintillator panel 10, the evaporation device 61 described above can be suitably used. A method for producing the radiation scintillator panel 10 using the evaporation device 61 will be described.
　《基板の陽極酸化処理》
　厚さ０．５ｍｍのアルミニウム板１の蛍光体を形成する側の表面の表面粗さ（Ｒｍａｘ）が所定の値になるように表面をバフ研磨した後、界面活性剤を２％含み５０℃に加温された脱脂液に６０秒間浸漬した後３０秒間水洗する。次に、基材を５０℃に加温された１０％ＮａＯＨ水溶液で３０秒間エッチングした後３０秒間水洗する。その後、１０％ＮＨＯ３水溶液で３０秒間洗浄し、３０秒間水洗する。 <Anodic oxidation treatment of substrate>
After buffing the surface so that the surface roughness (Rmax) of the surface of the 0.5 mm thick aluminum plate 1 on which the phosphor is to be formed becomes a predetermined value, the surface is kept at 50 ° C. containing 2% of a surfactant. It is immersed in a heated degreasing solution for 60 seconds and then washed with water for 30 seconds. Next, the substrate is etched with a 10% NaOH aqueous solution heated to 50 ° C. for 30 seconds and then washed with water for 30 seconds. Thereafter, it is washed with a 10% NHO3 aqueous solution for 30 seconds and then washed with water for 30 seconds.
　次に、上記アルミニウム板を電解液に浸漬し、基材を陽極、対極にカーボン板を用いて電解処理し、処理後１０秒間水洗して、１００℃で５分間乾燥させことでアルミニウム板の表面に陽極酸化膜３ａを形成した。 Next, the aluminum plate is immersed in an electrolytic solution, the substrate is subjected to an electrolytic treatment using an anode and a carbon plate as a counter electrode, washed with water for 10 seconds after the treatment, and dried at 100 ° C. for 5 minutes, whereby the surface of the aluminum plate An anodic oxide film 3a was formed.
　《基板の被覆》
　厚み０．５ｍｍの基板全面に、ＣＶＤ法により約２μｍの厚さのポリパラキシリレン膜３ｂを形成する。 <Coating of substrate>
A polyparaxylylene film 3b having a thickness of about 2 μm is formed on the entire surface of the substrate having a thickness of 0.5 mm by a CVD method.
　《シンチレータ層の形成》
　上記のように反射層設けた基板１をホルダ６４に取り付けるとともに、ボート６３にヨウ化セシウムとヨウ化タリウムとを含む粉末状の混合物を充填する（準備工程）。この場合、ボート６３と基板１との間隔を１００～１５００ｍｍに設定し、その設定値の範囲内のままで後述の蒸着工程の処理を行うのが好ましい。 <Formation of scintillator layer>
The substrate 1 provided with the reflection layer as described above is attached to the holder 64, and the boat 63 is filled with a powdery mixture containing cesium iodide and thallium iodide (preparation step). In this case, it is preferable that the distance between the boat 63 and the substrate 1 is set to 100 to 1500 mm, and the vapor deposition process described later is performed while maintaining the range of the set value.
　準備工程の処理を終えたら、真空ポンプ６６を作動させて真空容器６２の内部を排気し、真空容器６２の内部を０．１Ｐａ以下の真空雰囲気下にする（真空雰囲気形成工程）。 When the preparation process is completed, the vacuum pump 66 is operated to evacuate the inside of the vacuum vessel 62, and the inside of the vacuum vessel 62 is brought to a vacuum atmosphere of 0.1 Pa or less (vacuum atmosphere forming step).
　ここでいう「真空雰囲気下」とは、１００Ｐａ以下の圧力雰囲気下のことを意味し、０．１Ｐａ以下の圧力雰囲気下であるのが好適である。 Here, “under vacuum atmosphere” means under a pressure atmosphere of 100 Pa or less, and preferably under a pressure atmosphere of 0.1 Pa or less.
　その後、アルゴン等の不活性ガスを真空容器６２の内部に導入し、当該真空容器６２の内部を０．１Ｐａ以下の真空雰囲気下に維持する。次に、ホルダ６４のヒータと回転機構６５のモータとを駆動させ、ホルダ６４に取り付け済みの基板１をボート６３に対向させた状態で加熱しながら回転させる。 Thereafter, an inert gas such as argon is introduced into the vacuum vessel 62, and the inside of the vacuum vessel 62 is maintained in a vacuum atmosphere of 0.1 Pa or less. Next, the heater of the holder 64 and the motor of the rotating mechanism 65 are driven, and the substrate 1 attached to the holder 64 is rotated while being heated while facing the boat 63.
　この状態において電極からボート６３に電流を流し、ヨウ化セシウムとヨウ化タリウムとを含む混合物を７００～８００℃程度で所定時間加熱してその混合物を蒸発させる。その結果、基板１の表面に無数の柱状結晶体２ａが順次成長して、所望の厚さのシンチレータ層２が形成される（蒸着工程）。 In this state, a current is passed from the electrode to the boat 63, and the mixture containing cesium iodide and thallium iodide is heated at about 700 to 800 ° C. for a predetermined time to evaporate the mixture. As a result, innumerable columnar crystals 2a are sequentially grown on the surface of the substrate 1 to form a scintillator layer 2 having a desired thickness (evaporation process).
　《保護層の形成》
　前記シンチレータ層２を形成するヨウ化セシウム（ＣｓＩ）は、吸湿性が高く、露出したままにしておくと空気中の水蒸気を吸湿して潮解する。そこで、これを防止するために、ＣＶＤ法によりポリパラキシリレンをシンチレータパネル全面に５～３０μｍの厚さに被覆することで保護層４を形成する。ＣｓＩの柱状結晶には隙間があり、ポリパラキシリレンがこの狭い隙間に入り込むので、保護層がヨウ化セシウム（ＣｓＩ）に密着する。 <Formation of protective layer>
The cesium iodide (CsI) forming the scintillator layer 2 has a high hygroscopic property, and if left exposed, absorbs water vapor in the air and deliquesces. Therefore, in order to prevent this, the protective layer 4 is formed by covering the entire surface of the scintillator panel with polyparaxylylene to a thickness of 5 to 30 μm by the CVD method. Since there is a gap in the columnar crystal of CsI, and polyparaxylylene enters this narrow gap, the protective layer is in close contact with cesium iodide (CsI).
　これにより、本発明に係る放射線用シンチレータパネル１０を製造することができる。 Thereby, the scintillator panel 10 for radiation according to the present invention can be manufactured.
　（放射線画像検出器）
　以下に、上記放射線用シンチレータパネル１０の一適用例として、図４及び図５を参照しながら、当該放射線用シンチレータプレート１０を具備した放射線画像検出器１００の構成について説明する。なお、図４は放射線画像検出器１００の概略構成を示す一部破断斜視図である。また、図５は撮像パネル５１の拡大断面図である。 (Radiation image detector)
The configuration of the radiation image detector 100 including the radiation scintillator plate 10 will be described below as an application example of the radiation scintillator panel 10 with reference to FIGS. 4 and 5. FIG. 4 is a partially broken perspective view showing a schematic configuration of the radiation image detector 100. FIG. 5 is an enlarged cross-sectional view of the imaging panel 51.
　図４に示す通り、放射線画像検出器１００には、撮像パネル５１、放射線画像検出器１００の動作を制御する制御部５２、書き換え可能な専用メモリ（例えば、フラッシュメモリ）等を用いて撮像パネル５１から出力された画像信号を記憶する記憶手段であるメモリ部５３、撮像パネル５１を駆動して画像信号を得るために必要とされる電力を供給する電力供給手段である電源部５４、等が筐体５５の内部に設けられている。 As shown in FIG. 4, the radiation image detector 100 includes an imaging panel 51, a control unit 52 that controls the operation of the radiation image detector 100, a rewritable dedicated memory (for example, a flash memory), and the like. A memory unit 53 that is a storage unit that stores an image signal output from the power source unit 54, a power supply unit 54 that is a power supply unit that supplies power required to drive the imaging panel 51 and obtain an image signal, It is provided inside the body 55.
　筐体５５には、必要に応じて放射線画像検出器１００から外部に通信を行うための通信用のコネクタ５６、放射線画像検出器１００の動作を切り換えるための操作部５７、放射線画像の撮影準備の完了やメモリ部５３に所定量の画像信号が書き込まれたことを示す表示部５８、等が設けられている。 The housing 55 includes a communication connector 56 for performing communication from the radiation image detector 100 to the outside as necessary, an operation unit 57 for switching the operation of the radiation image detector 100, and preparation for radiographic imaging. A display unit 58 that indicates completion or a predetermined amount of image signal has been written in the memory unit 53 is provided.
　ここで、放射線画像検出器１００に電源部５４を設けるとともに放射線画像の画像信号を記憶するメモリ部５３を設け、コネクタ５６を介して放射線画像検出器１００を着脱自在にすれば、放射線画像検出器１００を持ち運びできる可搬構造とすることができる。 Here, if the radiation image detector 100 is provided with the power supply unit 54 and the memory unit 53 for storing the image signal of the radiation image, and the radiation image detector 100 is detachable via the connector 56, the radiation image detector is provided. It can be set as the portable structure which can carry 100.
　図５に示すように、撮像パネル５１は、放射線用シンチレータパネル１０と、放射線用シンチレータパネル１０からの電磁波を吸収して画像信号を出力する出力基板２０とから構成されている。 As shown in FIG. 5, the imaging panel 51 includes a radiation scintillator panel 10 and an output board 20 that absorbs electromagnetic waves from the radiation scintillator panel 10 and outputs an image signal.
　放射線用シンチレータパネル１０は放射線照射面側に配置されており、入射した放射線の強度に応じた電磁波を発光するように構成されている。 The radiation scintillator panel 10 is disposed on the radiation irradiation surface side, and is configured to emit an electromagnetic wave corresponding to the intensity of incident radiation.
　出力基板２０は、放射線用シンチレータパネル１０の放射線照射面と反対側の面に設けられており、放射線用シンチレータパネル１０側から順に、隔膜２０ａ、光電変換素子２０ｂ、画像信号出力層２０ｃ及び基板２０ｄを備えている。隔膜２０ａは、放射線用シンチレータパネル１０と他の層を分離するためのものである。 The output substrate 20 is provided on the surface opposite to the radiation irradiation surface of the radiation scintillator panel 10, and in order from the radiation scintillator panel 10 side, the diaphragm 20a, the photoelectric conversion element 20b, the image signal output layer 20c, and the substrate 20d. It has. The diaphragm 20a is for separating the scintillator panel 10 for radiation and other layers.
　光電変換素子２０ｂは、透明電極２１と、透明電極２１を透過して入光した電磁波により励起されて電荷を発生する電荷発生層２２と、透明電極２１に対しての対極になる対電極２３とから構成されており、隔膜２０ａ側から順に透明電極２１、電荷発生層２２、対電極２３が配置される。 The photoelectric conversion element 20 b includes a transparent electrode 21, a charge generation layer 22 that is excited by electromagnetic waves that have passed through the transparent electrode 21 to enter the light, and generates a charge, and a counter electrode 23 that is a counter electrode for the transparent electrode 21. The transparent electrode 21, the charge generation layer 22, and the counter electrode 23 are arranged in this order from the diaphragm 20a side.
　透明電極２１とは、光電変換される電磁波を透過させる電極であり、例えば、インジウムチンオキシド（ＩＴＯ）、ＳｎＯ２、ＺｎＯなどの導電性透明材料を用いて形成される。 The transparent electrode 21 is an electrode that transmits an electromagnetic wave that is photoelectrically converted, and is formed using a conductive transparent material such as indium tin oxide (ITO), SnO 2 , or ZnO.
　電荷発生層２２は、透明電極２１の一面側に薄膜状に形成されており、光電変換可能な化合物として光によって電荷分離する有機化合物を含有するものであり、電荷を発生し得る電子供与体及び電子受容体としての導電性化合物をそれぞれ含有している。電荷発生層２２では、電磁波が入射されると電子供与体は励起されて電子を放出し、放出された電子は電子受容体に移動して、電荷発生層２２内に電荷、即ち正孔と電子のキャリアが発生するようになっている。 The charge generation layer 22 is formed in a thin film on one surface side of the transparent electrode 21, and contains an organic compound that separates charges by light as a compound capable of photoelectric conversion. Each of them contains a conductive compound as an electron acceptor. In the charge generation layer 22, when an electromagnetic wave is incident, the electron donor is excited to emit electrons, and the emitted electrons move to the electron acceptor, and charge, that is, holes and electrons, are transferred into the charge generation layer 22. Career is going to occur.
　ここで、電子供与体としての導電性化合物としては、ｐ型導電性高分子化合物が挙げられ、ｐ型導電性高分子化合物としては、ポリフェニレンビニレン、ポリチオフェン、ポリ（チオフェンビニレン）、ポリアセチレン、ポリピロール、ポリフルオレン、ポリ（ｐ－フェニレン）またはポリアニリンの基本骨格を持つものが好ましい。 Here, examples of the conductive compound as the electron donor include a p-type conductive polymer compound. Examples of the p-type conductive polymer compound include polyphenylene vinylene, polythiophene, poly (thiophene vinylene), polyacetylene, polypyrrole, Those having a basic skeleton of polyfluorene, poly (p-phenylene) or polyaniline are preferred.
　また、電子受容体としての導電性化合物としてはｎ型導電性高分子化合物が挙げられ、ｎ型導電性高分子化合物としてはポリピリジンの基本骨格を持つものが好ましく、特にポリ（ｐ－ピリジルビニレン）の基本骨格を持つものが好ましい。 Examples of the conductive compound as the electron acceptor include an n-type conductive polymer compound. The n-type conductive polymer compound preferably has a polypyridine basic skeleton, and in particular, poly (p-pyridylvinylene). Those having the following basic skeleton are preferred.
　電荷発生層２２の膜厚は、光吸収量を確保するといった観点から１０ｎｍ以上（特に１００ｎｍ以上）が好ましく、また電気抵抗が大きくなりすぎないといった観点から、１μｍ以下（特に３００ｎｍ以下）が好ましい。 The film thickness of the charge generation layer 22 is preferably 10 nm or more (particularly 100 nm or more) from the viewpoint of securing the amount of light absorption, and is preferably 1 μm or less (particularly 300 nm or less) from the viewpoint that the electric resistance does not become too large.
　対電極２３は、電荷発生層２２の電磁波が入光される側の面と反対側に配置されている。対電極２３は、例えば、金、銀、アルミニウム、クロムなどの一般の金属電極や、透明電極２１の中から選択して用いることが可能であるが、良好な特性を得るためには仕事関数の小さい（４．５ｅＶ以下）金属、合金、電気伝導性化合物及びこれらの混合物を電極物質とするのが好ましい。 The counter electrode 23 is disposed on the opposite side of the surface of the charge generation layer 22 where the electromagnetic wave is incident. The counter electrode 23 can be selected and used from, for example, a general metal electrode such as gold, silver, aluminum, and chromium, or the transparent electrode 21. Small (4.5 eV or less) metals, alloys, electrically conductive compounds and mixtures thereof are preferably used as electrode materials.
　また、電荷発生層２２を挟む各電極（透明電極２１及び対電極２３）との間には、電荷発生層２２とこれら電極が反応しないように緩衝地帯として作用させるためのバッファー層を設けてもよい。バッファー層は、例えば、フッ化リチウム及びポリ（３，４－エチレンジオキシチオフェン）、ポリ（４－スチレンスルホナート）、２，９－ジメチル－４，７－ジフェニル［１，１０］フェナントロリンなどを用いて形成される。 In addition, a buffer layer may be provided between each electrode (transparent electrode 21 and counter electrode 23) sandwiching the charge generation layer 22 so as to act as a buffer zone so that the charge generation layer 22 and these electrodes do not react. Good. Examples of the buffer layer include lithium fluoride and poly (3,4-ethylenedioxythiophene), poly (4-styrenesulfonate), 2,9-dimethyl-4,7-diphenyl [1,10] phenanthroline, and the like. Formed using.
　画像信号出力層２０ｃは、光電変換素子２０ｂで得られた電荷の蓄積及び蓄積された電荷に基づく信号の出力を行うものであり、光電変換素子２０ｂで生成された電荷を画素毎に蓄積する電荷蓄積素子であるコンデンサ２４と、蓄積された電荷を信号として出力する画像信号出力素子であるトランジスタ２５とを用いて構成されている。 The image signal output layer 20c performs accumulation of charges obtained by the photoelectric conversion element 20b and output of a signal based on the accumulated charges. Charge for accumulating the charges generated by the photoelectric conversion element 20b for each pixel. The capacitor 24 is a storage element, and the transistor 25 is an image signal output element that outputs the stored charge as a signal.
　トランジスタ２５は、例えば、ＴＦＴ（薄膜トランジスタ）を用いるものとする。このＴＦＴは液晶ディスプレイ等に使用されている無機半導体系のものでも、有機半導体を用いたものでもよく、好ましくはプラスチックフィルム上に形成されたＴＦＴである。 As the transistor 25, for example, a TFT (Thin Film Transistor) is used. This TFT may be an inorganic semiconductor type used in a liquid crystal display or the like or an organic semiconductor, and is preferably a TFT formed on a plastic film.
　プラスチックフィルム上に形成されたＴＦＴとしては、アモルファスシリコン系のものが知られているが、その他、米国Ａｌｉｅｎ　Ｔｅｃｈｎｏｌｏｇｙ社が開発しているＦＳＡ（Ｆｌｕｉｄｉｃ　Ｓｅｌｆ　Ａｓｓｅｍｂｌｙ）技術、即ち単結晶シリコンで作製した微小ＣＭＯＳ（Ｎａｎｏｂｌｏｃｋｓ）をエンボス加工したプラスチックフィルム上に配列させることで、フレキシブルなプラスチックフィルム上にＴＦＴを形成するものとしてもよい。更に、Ｓｃｉｅｎｃｅ，２８３，８２２（１９９９）やＡｐｐｌ．Ｐｈｙｓ．Ｌｅｔｔ，７７１４８８（１９９８）、Ｎａｔｕｒｅ，４０３，５２１（２０００）等の文献に記載されているような、有機半導体を用いたＴＦＴであってもよい。 As TFTs formed on plastic films, amorphous silicon-based TFTs are known, but in addition, FSA (Fluidic Self Assembly) technology developed by Alien Technology in the United States, that is, microfabricated with single crystal silicon. TFTs may be formed on a flexible plastic film by arranging CMOS (Nanoblocks) on an embossed plastic film. Furthermore, Science, 283, 822 (1999) and Appl. Phys. It may be a TFT using an organic semiconductor as described in documents such as Lett, 771488 (1998), Nature, 403, 521 (2000).
　このように、本発明に用いられるトランジスタ２５としては、上記ＦＳＡ技術で作製したＴＦＴ及び有機半導体を用いたＴＦＴが好ましく、特に好ましいものは有機半導体を用いたＴＦＴである。この有機半導体を用いてＴＦＴを構成すれば、シリコンを用いてＴＦＴを構成する場合のように真空蒸着装置等の設備が不要となり、印刷技術やインクジェット技術を活用してＴＦＴを形成できるので製造コストが安価となる。更に加工温度を低くできることから、熱に弱いプラスチック基板上にも形成できる。 Thus, as the transistor 25 used in the present invention, a TFT manufactured by the FSA technique and a TFT using an organic semiconductor are preferable, and a TFT using an organic semiconductor is particularly preferable. If this organic semiconductor is used to form a TFT, equipment such as a vacuum deposition apparatus is not required as in the case where a TFT is formed using silicon, and the TFT can be formed using printing technology or inkjet technology. Is cheaper. Further, since the processing temperature can be lowered, it can be formed on a plastic substrate that is weak against heat.
　トランジスタ２５には、光電変換素子２０ｂで発生した電荷を蓄積するとともに、コンデンサ２４の一方の電極となる収集電極（図示せず）が電気的に接続されている。コンデンサ２４には光電変換素子２０ｂで生成された電荷が蓄積されるとともに、この蓄積された電荷はトランジスタ２５を駆動することで読み出される。即ち、トランジスタ２５を駆動させることで、放射線画像の画素毎の信号を出力させることができる。 The transistor 25 accumulates electric charges generated in the photoelectric conversion element 20b and is electrically connected to a collecting electrode (not shown) which is one electrode of the capacitor 24. The capacitor 24 accumulates charges generated by the photoelectric conversion element 20 b and reads the accumulated charges by driving the transistor 25. That is, by driving the transistor 25, a signal for each pixel of the radiation image can be output.
　基板２０ｄは、撮像パネル５１の支持体として機能するものであり、基板１と同様の素材で構成することが可能である。 The substrate 20d functions as a support for the imaging panel 51, and can be made of the same material as the substrate 1.
　次に、放射線画像検出器１００の作用について説明する。 Next, the operation of the radiation image detector 100 will be described.
　先ず放射線画像検出器１００に対し入射された放射線は、撮像パネル５１の放射線用シンチレータパネル１０側から基板２０ｄ側に向けて放射線を入射する。すると、放射線用シンチレータパネル１０に入射された放射線は、放射線用シンチレータパネル１０中のシンチレータ層２が放射線のエネルギーを吸収し、その強度に応じた電磁波を発光する。 First, the radiation incident on the radiation image detector 100 is incident from the radiation scintillator panel 10 side of the imaging panel 51 toward the substrate 20d side. Then, the radiation incident on the radiation scintillator panel 10 is absorbed by the scintillator layer 2 in the radiation scintillator panel 10 and emits electromagnetic waves corresponding to the intensity thereof.
　発光された電磁波の内、出力基板２０に入光される電磁波は出力基板２０の隔膜２０ａ、透明電極２１を貫通し、電荷発生層２２に到達する。そして、電荷発生層２２において電磁波は吸収され、その強度に応じて正孔と電子のペア（電荷分離状態）が形成される。 Among the emitted electromagnetic waves, the electromagnetic waves entering the output substrate 20 pass through the diaphragm 20a and the transparent electrode 21 of the output substrate 20 and reach the charge generation layer 22. Then, the electromagnetic wave is absorbed in the charge generation layer 22 and a hole-electron pair (charge separation state) is formed according to the intensity.
　その後、発生した電荷は、電源部５４によるバイアス電圧の印加により生じる内部電界により、正孔と電子はそれぞれ異なる電極（透明電極膜及び導電層）へ運ばれ、光電流が流れる。 Thereafter, the generated electric charges are transported to different electrodes (transparent electrode film and conductive layer) by an internal electric field generated by application of a bias voltage by the power supply unit 54, and a photocurrent flows.
　その後、対電極２３側に運ばれた正孔は画像信号出力層２０ｃのコンデンサ２４に蓄積される。蓄積された正孔はコンデンサ２４に接続されているトランジスタ２５を駆動させると、画像信号を出力するとともに、出力された画像信号はメモリ部５３に記憶される。 Thereafter, the holes carried to the counter electrode 23 side are accumulated in the capacitor 24 of the image signal output layer 20c. The accumulated holes output an image signal when the transistor 25 connected to the capacitor 24 is driven, and the output image signal is stored in the memory unit 53.
　以上の放射線画像検出器１００によれば、上記放射線用シンチレータパネル１０を備えているので光電変換効率を高めることができ、放射線画像における低線量撮影時のＳＮ比を向上させるとともに、画像ムラや線状ノイズの発生を防止することができる。 According to the radiation image detector 100 described above, since the radiation scintillator panel 10 is provided, the photoelectric conversion efficiency can be increased, the SN ratio at the time of low-dose imaging in the radiation image can be improved, and image unevenness and lines can be improved. The generation of noise can be prevented.
　以下、実施例を挙げて本発明を詳細に説明するが、本発明はこれらに限定されない。 Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.
　実施例
　［基板の作製］
　Ａ１１００－Ｈ１８アルミニウム板を０．５ｍｍに圧延後、蛍光体を形成する側の表面の表面祖が表１に示した値になるように表面をバフ研磨した後、界面活性剤を２％含み５０℃に加温された脱脂液に６０秒間浸漬した後３０秒間水洗した。次に、基材を５０℃に加温された１０％ＮａＯＨ水溶液で３０秒間エッチングした後３０秒間水洗した。その後、１０％ＮＨＯ３水溶液で３０秒間洗浄し、３０秒間水洗した。 Example [Production of Substrate]
After rolling the A1100-H18 aluminum plate to 0.5 mm and buffing the surface so that the surface of the phosphor-forming surface has the value shown in Table 1, it contains 2% surfactant. It was immersed in a degreasing solution heated to 0 ° C. for 60 seconds and then washed with water for 30 seconds. Next, the substrate was etched with a 10% NaOH aqueous solution heated to 50 ° C. for 30 seconds and then washed with water for 30 seconds. Thereafter, it was washed with a 10% NHO 3 aqueous solution for 30 seconds and then washed with water for 30 seconds.
　次に、上記アルミニウム板を、表１の電解条件に示す電解液に浸漬し、基材を陽極、対極にカーボン板を用いて表１の条件で電解処理し、処理後１０秒間水洗して、１００℃で５分間乾燥させた。 Next, the aluminum plate is immersed in an electrolytic solution shown in the electrolysis conditions of Table 1, the substrate is subjected to electrolytic treatment under the conditions of Table 1 using a carbon plate as an anode and a counter electrode, and washed with water for 10 seconds after the treatment. Dry at 100 ° C. for 5 minutes.
　次に、上記アルミニウム板をパンチ及びダイにより打ち抜いて、２５ｃｍ×２０ｃｍの長方形状で角部が曲率半径Ｒ＝３ｍｍの円弧状となっている基板を作製した。 Next, the aluminum plate was punched out with a punch and a die, and a substrate having a rectangular shape of 25 cm × 20 cm and an arc shape with a corner radius of curvature R = 3 mm was produced.
　上記電解処理によりアルミ基板表面に形成された陽極酸化皮膜を１０万倍の電子顕微鏡で観察し、表面に存在する孔の面積を、測定面積で除して有孔率を算出した。有孔率の測定結果、陽極酸化皮膜の膜厚、及び４５°正反射率の測定結果を表１に示す。 The anodized film formed on the surface of the aluminum substrate by the above electrolytic treatment was observed with an electron microscope of 100,000 times, and the porosity was calculated by dividing the area of the holes present on the surface by the measurement area. Table 1 shows the measurement results of the porosity, the film thickness of the anodized film, and the 45 ° regular reflectance.
　［基板の樹脂被覆］
　表１に示した実施例１～８、及び、比較例１～２に使用したアルミニウム基板をＣＶＤ装置の蒸着室に入れ、ポリパラキシリレンの原料が昇華した蒸気中に露出させておくことにより、基板の全面表面を２μｍの厚さのポリパラキシリレン膜で被服した。 [Resin coating on substrate]
By putting the aluminum substrates used in Examples 1 to 8 and Comparative Examples 1 and 2 shown in Table 1 into the vapor deposition chamber of the CVD apparatus and exposing them to the vapor in which the polyparaxylylene raw material was sublimated. The entire surface of the substrate was coated with a polyparaxylylene film having a thickness of 2 μm.
　また、実施例９の基板には、下記の手順でポリエステル膜を形成した。 Further, a polyester film was formed on the substrate of Example 9 by the following procedure.
　（ポリエステル膜の形成）
　バイロン６３０（東洋紡社製：高分子ポリエステル樹脂）　　　　１００質量部
　メチルエチルケトン（ＭＥＫ）　　　　　　　　　　　　　　　　１００質量部
　トルエン　　　　　　　　　　　　　　　　　　　　　　　　　　１００質量部
　上記処方を混合し、ビーズミルにて１５時間分散し、塗布液を得た。この塗布液をアルミニウム基板のシンチレータ形成面側に乾燥膜厚が２μｍになるようにバーコーターで塗布した。 (Polyester film formation)
Byron 630 (manufactured by Toyobo Co., Ltd .: polymer polyester resin) 100 parts by mass Methyl ethyl ketone (MEK) 100 parts by mass Toluene 100 parts by mass The above formulations were mixed and dispersed in a bead mill for 15 hours to obtain a coating solution. This coating solution was applied to the scintillator forming surface side of the aluminum substrate with a bar coater so that the dry film thickness was 2 μm.
　尚、実施例１０の基板には、基板を被覆膜は設けなかった。 The substrate of Example 10 was not provided with a coating film.
　［シンチレータ層の形成］
　上記にて得られたアルミニウム基板に、下記手順でシンチレータ層を形成した。 [Formation of scintillator layer]
A scintillator layer was formed on the aluminum substrate obtained above by the following procedure.
　基板の光吸収層側にシンチレータ蛍光体（ＣｓＩ：０．００３Ｔｌ）を、図３に示す蒸着装置を使用して蒸着させシンチレータ（蛍光体）層を形成した。 A scintillator phosphor (CsI: 0.003Tl) was vapor-deposited on the light absorption layer side of the substrate using the vapor deposition apparatus shown in FIG. 3 to form a scintillator (phosphor) layer.
　すなわち、まず、上記蛍光体原料を蒸着材料として抵抗加熱ルツボに充填し、また回転する支持体ホルダに支持体を設置し、支持体と蒸発源との間隔を４００ｍｍに調節した。続いて蒸着装置内を一旦排気し、Ａｒガスを導入して０．５Ｐａに真空度を調整した後、１０ｒｐｍの速度で支持体を回転しながら基板の温度を１５０℃に保持した。次いで、抵抗加熱ルツボを加熱して蛍光体を蒸着しシンチレータ層の膜厚が４００μｍとなったところで蒸着を終了させシンチレータパネル（放射線像変換パネル）を得た。 That is, first, the above-mentioned phosphor raw material was filled in a resistance heating crucible as an evaporation material, and a support was placed on a rotating support holder, and the distance between the support and the evaporation source was adjusted to 400 mm. Subsequently, the inside of the vapor deposition apparatus was once evacuated, Ar gas was introduced and the degree of vacuum was adjusted to 0.5 Pa, and then the substrate temperature was maintained at 150 ° C. while rotating the support at a speed of 10 rpm. Next, the resistance heating crucible was heated to deposit the phosphor, and when the scintillator layer had a thickness of 400 μm, the deposition was terminated to obtain a scintillator panel (radiation image conversion panel).
　［評価］
　得られたシンチレータパネルを、ＰａｘＳｃａｎ（Ｖａｒｉａｎ社製ＦＰＤ：２５２０）にセットし、シンチレータパネル輝度と鮮鋭性を、以下に示す方法で評価した。 [Evaluation]
The obtained scintillator panel was set in PaxScan (FPD: 2520 manufactured by Varian), and scintillator panel brightness and sharpness were evaluated by the methods shown below.
　〈輝度の評価方法〉
　管電圧７０ｋＶｐのＸ線を試料の裏面（蛍光体層が形成されていない面）から照射し、画像データを、シンチレータを配置したＦＰＤで検出し、画像の平均シグナル値を発光輝度とした。測定結果を下記表１に示す。ただし、表１中、試料の輝度を示す値は、比較例１の試料の発光輝度を１．０とした相対値である。 <Brightness evaluation method>
X-rays with a tube voltage of 70 kVp were irradiated from the back surface of the sample (the surface on which the phosphor layer was not formed), the image data was detected with an FPD provided with a scintillator, and the average signal value of the image was taken as the emission luminance. The measurement results are shown in Table 1 below. However, in Table 1, the value indicating the luminance of the sample is a relative value with the emission luminance of the sample of Comparative Example 1 being 1.0.
　〈鮮鋭性の評価方法〉
　鉛製のＭＴＦチャートを通して管電圧８０ｋＶｐのＸ線をＦＰＤの放射線入射面側に照射し、画像データを検出しハードディスクに記録した。その後、ハードディスク上の記録をコンピュータで分析して当該ハードディスクに記録されたＸ線像の変調伝達関数ＭＴＦ（空間周波数１サイクル／ｍｍにおけるＭＴＦ値）を鮮鋭性の指標とした。表中、ＭＴＦ値が高いほど鮮鋭性に優れていることを示す。なお、ＭＴＦは、Ｍｏｄｕｌａｔｉｏｎ　Ｔｒａｎｓｆｅｒ　Ｆｕｎｃｔｉｏｎの略号である。 <Evaluation method of sharpness>
X-rays with a tube voltage of 80 kVp were irradiated to the radiation incident surface side of the FPD through a lead MTF chart, and image data was detected and recorded on a hard disk. Thereafter, the recording on the hard disk was analyzed by a computer, and the modulation transfer function MTF (MTF value at a spatial frequency of 1 cycle / mm) of the X-ray image recorded on the hard disk was used as an index of sharpness. In the table, the higher the MTF value, the better the sharpness. Note that MTF is an abbreviation for Modulation Transfer Function.
　上記評価結果を表１に示す。 The evaluation results are shown in Table 1.
　〈基板の腐食度の評価方法〉
　シンチレータパネルを３０℃５０％の環境下に３週間放置したのち、シンチレータ層を流水で除去して、アルミ基板表面の腐食状態を観察し、下記の基準で評価し表１に記載した。 <Method of evaluating the degree of corrosion of the substrate>
The scintillator panel was left in an environment of 30 ° C. and 50% for 3 weeks, the scintillator layer was removed with running water, the corrosion state of the aluminum substrate surface was observed, evaluated according to the following criteria, and listed in Table 1.
　○：腐食の発生無し
　△：腐食面積が１％未満
　×：腐食面積が１％以上 ○: No corrosion occurred △: Corrosion area is less than 1% ×: Corrosion area is 1% or more
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示した結果から明らかなように、本発明に係る実施例は比較例に比べ、輝度、ＭＴＦ、及び耐食性において優れていることが分かる。 As is clear from the results shown in Table 1, it can be seen that the examples according to the present invention are superior in luminance, MTF, and corrosion resistance as compared with the comparative examples.

Claims (12)

  1. 　陽極酸化皮膜で被覆されたアルミニウム又はアルミニウム合金からなる基板上にシンチレータ層を設けて成るシンチレータパネルであって、当該陽極酸化皮膜が、当該基板の表面を、研磨により表面粗度が最大高さ（Ｒｍａｘ）で３．０μｍ以下になるように平坦化した後に、陽極酸化処理することで形成されたことを特徴とするシンチレータパネル。 A scintillator panel in which a scintillator layer is provided on a substrate made of aluminum or an aluminum alloy coated with an anodized film, wherein the anodized film has a maximum surface roughness by polishing the surface of the substrate ( A scintillator panel formed by performing anodization after flattening to Rmax) of 3.0 μm or less.
  2. 　前記基板のシンチレータ層が形成される側の表面における、入射角４５°での可視光の正反射率が、６０％以上であることを特徴とする請求の範囲第１項に記載のシンチレータパネル。 The scintillator panel according to claim 1, wherein the regular reflectance of visible light at an incident angle of 45 ° on the surface of the substrate on which the scintillator layer is formed is 60% or more.
  3. 　前記基板の角部が、曲率半径Ｒの円弧状となるように加工されていることを特徴とする請求の範囲第１項又は第２項に記載のシンチレータパネル。 The scintillator panel according to claim 1 or 2, wherein the corner portion of the substrate is processed so as to have an arc shape with a radius of curvature R.
  4. 　前記曲率半径Ｒの範囲が、１～１０ｍｍであることを特徴とする請求の範囲第３項に記載のシンチレータパネル。 The scintillator panel according to claim 3, wherein a range of the radius of curvature R is 1 to 10 mm.
  5. 　前記基板の少なくともシンチレータ層が形成される側の表面が、樹脂で被覆されていることを特徴とする請求の範囲第１項から第４項のいずれか一項に記載のシンチレータパネル。 The scintillator panel according to any one of claims 1 to 4, wherein at least a surface of the substrate on which the scintillator layer is formed is coated with a resin.
  6. 　前記樹脂が、ポリエステルを含む樹脂であることを特徴であることを特徴とする請求の範囲第５項に記載のシンチレータパネル。 The scintillator panel according to claim 5, wherein the resin is a resin containing polyester.
  7. 　前記樹脂による被覆が、ＣＶＤ法により基板全面に形成されたポリパラキシリレン膜による被覆であることを特徴とする請求の範囲第５項に記載のシンチレータパネル。 The scintillator panel according to claim 5, wherein the coating with the resin is a coating with a polyparaxylylene film formed on the entire surface of the substrate by a CVD method.
  8. 　前記基板の陽極酸化皮膜の有穴率が、６０％以下であることを特徴とする請求の範囲第１項から第７項のいずれか一項に記載のシンチレータパネル。 The scintillator panel according to any one of claims 1 to 7, wherein the porosity of the anodized film on the substrate is 60% or less.
  9. 　前記陽極酸化皮膜の厚さが、２００～２０００ｎｍであることを特徴とする請求の範囲第１項から第８項のいずれか一項に記載のシンチレータパネル。 The scintillator panel according to any one of claims 1 to 8, wherein the anodized film has a thickness of 200 to 2000 nm.
  10. 　前記シンチレータ層が、ヨウ化セシウムと少なくとも１種類以上のタリウム化合物を含む添加剤を原材料として気相法にて形成されたことを特徴とする請求の範囲第１項から第９項のいずれか一項に記載のシンチレータパネル。 10. The scintillator layer according to any one of claims 1 to 9, wherein the scintillator layer is formed by a vapor phase method using an additive containing cesium iodide and at least one kind of thallium compound as a raw material. The scintillator panel according to item.
  11. 　シンチレータパネル全面を覆う樹脂からなる保護膜を有することを特徴とする請求の範囲第１項から第１０項のいずれか一項に記載のシンチレータパネル。 The scintillator panel according to any one of claims 1 to 10, further comprising a protective film made of a resin covering the entire surface of the scintillator panel.
  12. 　前記保護膜として、ＣＶＤ法により形成されたポリパラキシリレン膜を有することを特徴とする請求の範囲第１１項に記載のシンチレータパネル。 12. The scintillator panel according to claim 11, wherein the protective film includes a polyparaxylylene film formed by a CVD method.
PCT/JP2009/053673 2008-05-29 2009-02-27 Scintillator panel WO2009144984A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003262671A (en) * 2002-03-07 2003-09-19 Hamamatsu Photonics Kk Scintillator panel and method for manufacturing the same
JP2004251883A (en) * 2002-06-28 2004-09-09 Agfa Gevaert Nv Storage phosphor screen free from bonding agent
JP2005049341A (en) * 2003-07-04 2005-02-24 Agfa Gevaert Nv Image storage phosphor or scintillator panel coated onto flexible support
JP2006133126A (en) * 2004-11-08 2006-05-25 Konica Minolta Medical & Graphic Inc Radiation image conversion panel

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003262671A (en) * 2002-03-07 2003-09-19 Hamamatsu Photonics Kk Scintillator panel and method for manufacturing the same
JP2004251883A (en) * 2002-06-28 2004-09-09 Agfa Gevaert Nv Storage phosphor screen free from bonding agent
JP2005049341A (en) * 2003-07-04 2005-02-24 Agfa Gevaert Nv Image storage phosphor or scintillator panel coated onto flexible support
JP2006133126A (en) * 2004-11-08 2006-05-25 Konica Minolta Medical & Graphic Inc Radiation image conversion panel

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