JP6662291B2 - Inspection equipment for large structures - Google Patents

Description

  The present invention relates to an inspection device for a large structure.

  2. Description of the Related Art In recent years, deterioration of reliability due to aging of a building such as an expressway, which has passed a long period of time, that is, a large structure, has become a problem. Although repairs are urgently needed, the importance of non-destructive inspection methods that do not involve the destruction of used concrete and the like are increasing because it is necessary to grasp the internal structure and the like in advance.

  Non-destructive inspection methods include an ultrasonic flaw detection method and an X-ray transmission test. Among them, the X-ray transmission test irradiates a large structure made of concrete or the like with high-energy X-rays and transmits the large structure. This is a method of detecting X-rays with a flat panel detector and obtaining a transmission image corresponding to the intensity of the transmitted X-rays (Patent Document 1).

JP-A-10-197456

  However, in the conventional indirect conversion type flat panel detector for medical or industrial inspection, since the thickness of the phosphor layer for converting transmitted X-rays into scintillation light is too thin, absorption of high-energy transmitted X-rays is small and sensitivity is low. Was inadequate. On the other hand, when the sensitivity is improved by increasing the thickness of the phosphor layer, scattering of scintillation light in the phosphor layer becomes remarkable, and the obtained transmitted image becomes rather unclear. It had been.

  Therefore, an object of the present invention is to provide a large structure inspection apparatus having a configuration optimized for detecting high-energy transmitted X-rays.

This object is achieved by any of the following technical means.
(1) an irradiation function for irradiating a large structure with X-rays from an X-ray source having an acceleration voltage of 500 kV to 30 MV, a detection function for detecting X-rays transmitted through the large structure with a radiation detector, An inspection apparatus for a large structure, comprising: a substrate, a partition placed on the substrate, and a phosphor layer filled in a cell partitioned by the partition. A scintillator panel, wherein the phosphor layer is composed of a plurality of modes having different compositions and / or thicknesses for each cell, and the X-ray absorptivity of the phosphor layer having the maximum X-ray absorptivity is P; A large structure inspection apparatus that satisfies the relationship of P / Q ≧ 1.5, where Q is the X-ray absorptance of the phosphor layer having the minimum absorptivity.
(2) The inspection apparatus for a large structure according to (1), wherein the substrate and the partition placed on the substrate have a reflectance of 25 to 85%.
(3) The large-sized panel according to (1) or (2), wherein the scintillator panel has a reflective layer between the partition and the phosphor layer, and the reflective layer contains a metal oxide. Inspection equipment for structures.
(4) The inspection device for a large structure according to (3), wherein the average thickness of the reflection layer is 5 to 50 μm.
(5) The large structure according to (3) or (4), wherein the metal oxide is a compound selected from the group consisting of titanium oxide, zirconium oxide, aluminum oxide, barium oxide, bismuth oxide, and gadolinium oxide. Inspection equipment.
(6) The average thickness of the reflective layer in the upper half of the cell is larger than the average thickness of the reflective layer in the lower half of the cell. Inspection equipment for large structures.
(7) The large structure according to any one of (1) to (6), wherein the phosphor layer contains a particulate phosphor, and the phosphor has an average primary particle diameter of 1 to 50 μm. Inspection equipment.
(8) The large-sized panel according to any one of (1) to (7), wherein the scintillator panel has a shielding layer between the partition and the phosphor layer, and the shielding layer is made of metal. Inspection equipment for structures.
(9) The inspection device for a large structure according to any one of (1) to (8), wherein the height of the partition wall is 0.4 mm or more.

  ADVANTAGE OF THE INVENTION According to this invention, the internal structure etc. of a large structure can be inspected with high precision, without destruction.

It is sectional drawing which represented typically the structure of the radiation detector with which the inspection apparatus of the large structure of this invention is provided. It is sectional drawing which represented typically the structure of the scintillator panel with which the test | inspection apparatus of the large structure of this invention is provided. It is sectional drawing which represented typically the structure of the radiation detector with which the inspection apparatus of the large structure of this invention is provided. It is the perspective view which represented typically the structure of the scintillator panel with which the test | inspection apparatus of the large structure of this invention is provided. It is the perspective view which represented typically the structure of the scintillator panel with which the test | inspection apparatus of the large structure of this invention is provided.

  Hereinafter, a specific configuration of the inspection apparatus for a large structure according to the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

  FIG. 1 is a cross-sectional view schematically illustrating a configuration of a radiation detector included in the large structure inspection apparatus of the present invention. The radiation detector 1 includes a scintillator panel 2, an output board 3, and a power supply unit 11. The scintillator panel 2 has a phosphor layer 6, and the phosphor layer 6 absorbs incident X-ray energy and emits electromagnetic waves having a wavelength in the range of 300 to 800 nm, ie, from visible light to ultraviolet light. It emits scintillation light, which is electromagnetic waves (light) in a range that covers infrared light.

  The scintillator panel 2 includes a substrate 4, a space defined thereon, a partition wall 5 for forming a cell, a phosphor layer 6 filled in the space partitioned by the partition wall 5, and a surface of the partition wall 5. It is composed of a shielding layer 12 formed between the phosphor layer 6 and the reflection layer 13.

  The output substrate 3 has a photoelectric conversion layer 8 and an output layer 9 on which a pixel including a photoelectric conversion element and a TFT is formed two-dimensionally on a substrate 10. The radiation detector 1 is obtained by bonding or adhering the light exit surface of the scintillator panel 2 and the photoelectric conversion layer 8 of the output substrate 3 via a diaphragm layer 7 made of a polyimide resin or the like. When the light emitted from the phosphor layer 6 reaches the photoelectric conversion layer 8, the photoelectric conversion is performed in the photoelectric conversion layer 8, and an electric signal is output through the output layer 9. In the scintillator panel provided in the large structure inspection apparatus of the present invention, since each cell is partitioned by a partition, the size and pitch of the pixels of the photoelectric conversion elements arranged in a grid, and the size of the cell of the scintillator panel By matching the pitch and the pitch, each pixel of the photoelectric conversion element can be associated with each cell of the scintillator panel.

  The scintillator panel provided in the large structure inspection apparatus according to the present invention includes a substrate, a partition placed on the substrate, and a phosphor layer filled in a cell partitioned by the partition. It is characterized by.

  The substrate refers to a flat support on which a partition is to be placed. Examples of the material of the substrate include a polymer, a semiconductor, a metal, a ceramic, and a glass. Examples of the polymer compound include polyester, cellulose acetate, polyamide, polyimide, polycarbonate, and carbon fiber reinforced resin. Examples of the semiconductor include silicon, germanium, gallium arsenide, gallium phosphide, and gallium nitrogen. Examples of the metal include aluminum, iron, copper, lead, tungsten, and molybdenum. Ceramics include, for example, aluminum oxide, aluminum nitride, mullite or steatite. Examples of the glass include quartz, borosilicate glass, and chemically strengthened glass.

  When irradiated with high energy X-rays, most of the X-rays are scattered in the large structure, and when the X-rays are directly irradiated on the scintillator panel, the obtained transmitted image, that is, the sharpness of the image is reduced. Therefore, the substrate selectively absorbs scattered low-energy X-rays (hereinafter, “scattered X-rays”) and selectively scatters non-scattered high-energy X-rays (hereinafter, “straight X-rays”). What penetrates is preferable. More specifically, a substrate having an X-ray absorption characteristic equivalent to that of lead having a thickness of 5 to 20 mm is preferable.

  The scintillator panel provided in the large structure inspection apparatus of the present invention has a partition. Since the partition walls suppress the scattering of the scintillation light and can absorb the scattered X-rays, the sharpness of the obtained image is improved.

  FIG. 2 is a cross-sectional view schematically showing a configuration of a scintillator panel provided in the large structure inspection apparatus of the present invention.

  The height L1 of the partition wall 5 is preferably 0.4 to 50 mm, more preferably 1 to 20 mm. When L1 exceeds 50 mm, straight X-rays are scattered in the phosphor layer, and the sharpness of the obtained image may be reduced. On the other hand, if L1 is less than 0.4 mm, high-energy straight X-rays cannot be sufficiently converted into scintillation light, and the luminance of the scintillator panel may decrease.

  The distance L2 between the adjacent partition walls is preferably from 0.1 to 5 mm, more preferably from 0.2 to 1 mm. If L2 is less than 0.1 mm, it becomes difficult to form a phosphor layer in the cell. On the other hand, if L2 exceeds 5 mm, the sharpness of the obtained image may decrease.

  The bottom width L3 of the partition wall is preferably 0.01 to 0.3 mm, more preferably 0.03 to 0.15 mm. If L3 is less than 0.01 mm, pattern defects are likely to occur. On the other hand, when L3 exceeds 0.3 mm, the volume of the phosphor layer becomes insufficient, and the luminance of the scintillator panel may decrease.

  The top width L4 of the partition wall is preferably 0.005 to 0.2 mm, more preferably 0.02 to 0.1 mm. When L4 is less than 0.005 mm, the strength of the partition walls decreases, and pattern defects easily occur. On the other hand, if L4 exceeds 0.2 mm, the area from which the scintillation light can be extracted from the phosphor layer becomes narrow, and the luminance of the scintillator panel may decrease.

  For L1 to L4, the cross section of the scintillator panel, which is perpendicular to the substrate, is exposed by a polishing device such as a cross section polisher, and the cross section is observed and measured with a scanning electron microscope (for example, S2400; manufactured by Hitachi, Ltd.). Can be. Here, the width of the partition at the contact portion between the partition and the substrate is L3. The width of the top of the partition is L4.

  The partition walls are preferably made of an inorganic material in order to increase the X-ray absorption and light reflectance in addition to the strength. Here, the inorganic substance refers to a compound composed of a simple carbon compound (e.g., allotrope of carbon such as graphite or diamond) and an element other than carbon. In addition, `` consisting of inorganic substances '' does not strictly exclude the presence of components other than inorganic substances, and does not include impurities contained in the inorganic substance itself as a raw material or inorganic substances such as impurities mixed in the process of manufacturing partition walls. The presence of other components is acceptable. Examples of the inorganic substance serving as a raw material of the partition include metals such as aluminum, iron, copper, lead, tungsten, and molybdenum, metal oxides such as titanium oxide and aluminum oxide, and glasses such as borosilicate glass.

  The porosity of the partition walls is preferably 25% or less. When the porosity exceeds 25%, the strength of the partition walls may be insufficient. The porosity of the partition wall is obtained by taking an image of the cross section of the partition wall perpendicular to the substrate with a scanning electron microscope, distinguishing the solid portion and the void portion of the partition by binarization, and analyzing the ratio of the void portion by image analysis. Can be determined and measured.

  In the scintillator panel provided in the large structure inspection device of the present invention, it is preferable that the reflectance of the substrate constituting the scintillator panel and the partition walls mounted on the substrate is 25 to 85%. Here, the substrate and the partition placed on the substrate refer to those in which only the partition is placed on the substrate, and the cells partitioned by the partition are not filled with the phosphor layer. Say. In the case where a reflective layer or a shielding layer, which will be described later, is formed on the surfaces of the substrate and the partition before the phosphor layer is filled, the state includes those layers. The reflectance refers to the SCI reflectance at a wavelength of 530 nm measured using a spectrophotometer (for example, CM-2600d; manufactured by Konica Minolta), and refers to the reflectance of the substrate and the partition walls mounted on the substrate. The reflectance refers to the reflectance when light is applied to the substrate and the partition from the side where the partition is mounted. If the reflectance is less than 25%, the luminance of the scintillator panel may decrease. On the other hand, if the reflectance exceeds 85%, the sharpness of an image may be reduced. It is considered that the decrease in the sharpness of the image is caused by a decrease in absorption of scintillation light by the substrate and the partition walls, and an increase in the ratio of scintillation light by scattered X-rays reaching the photoelectric conversion layer. That is, since scattered X-rays have low energy, scintillation light is easily emitted only on the side closer to the substrate in the phosphor layer. Here, when the reflectance of the substrate and the partition placed on the substrate exceeds 85%, light emitted by scattered X-rays near the substrate is efficiently extracted to the photoelectric conversion layer side. Sharpness may decrease. On the other hand, when the reflectance is 85% or less, the light emitted by the scattered X-rays is appropriately absorbed by the partition walls in the process of traveling a long distance from the substrate side to the photoelectric conversion layer side. Since the straight X-rays emit scintillation light almost uniformly at any part from the substrate side of the phosphor layer to the photoelectric conversion layer side, the influence of the absorption by the partition walls is smaller than that of the scattered X-rays. Therefore, it is considered that the influence of the scattered X-rays is relatively reduced, and the sharpness of the image is improved.

  The scintillator panel provided in the large structure inspection apparatus of the present invention preferably has a reflective layer containing a metal oxide between the partition and the phosphor layer. Here, having a reflective layer between the partition and the phosphor layer means, for example, a state in which the reflective layer is formed on the surface of the partition and the partition in contact with the phosphor layer. The reflection layer preferably contains a metal oxide as a main component. Note that the phrase “contains a metal oxide as a main component” means that the proportion of the metal oxide in the reflective layer is 50% by volume or more. Since the scintillator panel has the reflective layer containing the metal oxide between the partition and the phosphor layer, the reflectance of the substrate and the partition placed on the substrate can be controlled to a suitable value. .

  The average thickness of the reflection layer is preferably 5 to 50 μm. Here, the average thickness of the reflective layer means a value obtained by dividing the area of the reflective layer of 10 cells selected at random in the cross section of the scintillator panel perpendicular to the substrate by the length of the reflective layer. The formation length of the reflective layer refers to the total extension of the length of the section where the reflective layer is in contact with the lower layer (such as a partition or a shielding layer) in the cross section of the ten cells. More specifically, the average thickness of the reflective layer is calculated by exposing a cross section of the scintillator panel perpendicular to the substrate with a polishing device, observing the cross section with a scanning electron microscope, and performing image processing. Can be.

  If the average thickness of the reflective layer is less than 5 μm, the reflectivity may be insufficient. On the other hand, if the thickness exceeds 50 μm, the reflectance may be too high and the sharpness of the obtained image may be reduced. Further, since the volume of the phosphor layer is insufficient, the luminance of the scintillator panel may decrease.

  The metal oxide contained in the reflective layer is preferably a compound selected from the group consisting of titanium oxide, zirconium oxide, aluminum oxide, barium oxide, bismuth oxide and gadolinium oxide in order to achieve more suitable reflectance. The reflective layer composed of these oxides is preferable because it has an appropriate reflectance. Note that barium oxide, bismuth oxide, and gadolinium oxide, which are heavy elements, are more preferable in order to further enhance the sharpness of an image by absorbing scattered X-rays generated in the phosphor layer.

  When the scintillator panel provided in the inspection apparatus for a large structure of the present invention has a reflective layer, the average thickness of the reflective layer in the upper half of the cell is larger than the average thickness of the reflective layer in the lower half of the cell. Is preferred. Here, the average thickness of the reflective layer in the upper half of the cell refers to the area of the upper half of the cell, that is, the height of the partition wall, for ten randomly selected cells in the cross section of the scintillator panel perpendicular to the substrate. This is a value obtained by dividing the area of the reflective layer formed in the region above the median of the height L1 (the bisecting point of the height L1 of the partition) by the length of the reflective layer. Similarly, the average thickness of the reflective layer in the lower half of the cell is defined as the area of the lower half of the cell, that is, the partition wall, for 10 randomly selected cells in a cross section of the scintillator panel, which is perpendicular to the substrate. This is a value obtained by dividing the area of the reflective layer formed in a region below the median of the height L1 (the bisecting point of the height L1 of the partition) by the length of the reflective layer. With such a configuration, scintillation light due to scattered X-rays generated at the bottom of the cell is easily absorbed by the partition walls, and the sharpness of an image is easily improved.

  The scintillator panel provided in the large structure inspection apparatus of the present invention preferably has a metal-containing shielding layer between the partition and the phosphor layer. Since the scintillator panel has a shielding layer containing a metal between the partition and the phosphor layer, leakage of scintillation light to an adjacent cell can be suppressed. When the shielding layer is an X-ray absorbing layer having an appropriate X-ray absorbing property, scattered X-rays generated when high-energy straight X-rays interact with the phosphor layer in the cell are absorbed. As a result, since leakage to adjacent cells can be suppressed, a decrease in sharpness of an obtained image can be suppressed. The shielding layer preferably contains a metal as a main component. In addition, that the metal is a main component means that the ratio of the metal in the shielding layer is 50% by volume or more.

  Examples of the shielding layer forming method include a vacuum film forming method such as a vacuum evaporation method, a sputtering method, and a CVD method, a plating method, a paste coating method, and a spraying method using a spray. Examples of the metal contained in the shielding layer include aluminum, chromium, silver, tungsten, molybdenum, and lead, and silver, tungsten, molybdenum, or lead, which has a high X-ray absorption rate, is preferable. The average thickness of the shielding layer is preferably 0.0001 to 0.5 mm. If the average thickness of the shielding layer is less than 0.0001 mm, the effect of suppressing leakage of scintillation light and the effect of absorbing X-rays tend to be insufficient. On the other hand, if the thickness exceeds 0.5 mm, the volume of the phosphor layer becomes insufficient, and the luminance of the scintillator panel may decrease. The average thickness of the shielding layer can be calculated in the same manner as the average thickness of the reflection layer.

  When both a shielding layer and a reflecting layer are formed between the partition and the phosphor layer, a reflecting layer is formed on the shielding layer in order to avoid insufficient reflectance due to absorption by the shielding layer. Is preferred.

In the scintillator panel provided in the large structure inspection device of the present invention, the cells partitioned by the partition walls are filled with the phosphor layer. Examples of the phosphor contained in the phosphor layer include CsI, CsBr, BaF ₂ , BaFI, BaFBr, GOS (Gd ₂ O ₂ S), GSO (Gd ₂ SiO ₅ ), BGO (BiGe ₃ O ₁₂ ), and LSO. (Lu ₂ SiO ₅ ), LuAP (LuAlO ₃ ), PbWO ₄ or CaWO ₄ . An activator may be added to the phosphor to increase luminous efficiency. Examples of the activator added to the phosphor include indium (In), thallium (Tl), lithium (Li), potassium (K), rubidium (Rb), sodium (Na), terbium (Tb), and europium (Eu). ) Or praseodymium (Pr).

  In the scintillator panel provided in the large structure inspection apparatus of the present invention, the phosphor layer preferably contains a particulate phosphor, and the phosphor preferably has an average primary particle diameter of 1 to 50 μm. When the phosphor layer contains a granular phosphor, the scattering of the scintillation light in the phosphor layer can be controlled to a suitable one, and the partition walls can appropriately absorb the scintillation light due to the scattered X-rays. The sharpness of the image is improved.

  The term “the phosphor layer contains the particulate phosphor” means that, in the cross section of the scintillator panel, which is perpendicular to the substrate, the major axis and the minor section of all the phosphors filled in 10 cells selected at random. The average value of the values obtained by measuring the diameter and dividing the major axis by the minor axis is 10 or less. In addition, the average primary particle diameter of the phosphor is a cross-sectional area of the scintillator panel, which is perpendicular to the substrate, of all granular phosphors filled in 10 cells selected at random, and is equivalent to a circle-converted particle of a cross-sectional area. The diameter is calculated, and the weighted average value is obtained by weighting them by the area ratio. More specifically, the average primary particle diameter of the phosphor is calculated by exposing a cross section of the scintillator panel perpendicular to the substrate with a polishing device, observing the cross section with a scanning electron microscope, and performing image processing. be able to.

Further, in order to control the scattering of the scintillation light in the phosphor layer containing the phosphor particles, it is preferable to fill the space between the phosphor particles with a resin having a high refractive index. GOS (Gd ₂ O ₂ S) doped with thallium (Tl) is an example of the granular phosphor.

  In the scintillator panel of the present invention, it is preferable that the phosphor layer filled in the cells partitioned by the partition walls has a plurality of modes having different compositions and / or thicknesses. With such a configuration, a scintillator panel in which the phosphor layer is composed of the phosphor layers of a plurality of modes having different X-ray absorptivity is obtained. Here, the X-ray absorptance refers to the absorptivity of each phosphor layer for 1 MeV X-rays, and is calculated based on the composition and thickness of each phosphor layer using EGS5 which is a radiation simulation program. Can be.

  As a method of forming a phosphor layer composed of a plurality of modes having different compositions and / or thicknesses, for example, a method is used in which a cell is partitioned by partition walls and only a specific cell is fluoresced via a patterned metal mask. There is a method of repeating the method of vacuum printing the body paste using a plurality of types of phosphor pastes.

  The scintillator panel provided in the inspection apparatus for large structures according to the present invention is used for inspection of large structures, and has high sensitivity to high-energy X-rays and sharpness of an image. It is possible to inspect the internal structure and the like of an object with high accuracy while being non-destructive. Here, the large-sized structure means that the minimum width is 20 cm or more and the transmittance of X-rays having an energy of 500 keV is a ready mixed concrete specified by JIS A5308, usually 18-8-20-N. Refers to an object having a transmittance smaller than the transmittance of the cured product of the portion having a thickness of 20 cm.

  The inspection apparatus for a large structure according to the present invention includes an irradiation function for irradiating the large structure with X-rays from an X-ray source having an acceleration voltage of 500 kV to 30 MV, and an X-ray transmitted through the large structure. And a detection function for detecting by means of In other words, the inspection apparatus for a large structure according to the present invention irradiates the large structure with X-rays from an X-ray source having an acceleration voltage of 500 kV to 30 MV. And a detection step of detecting with a radiation detector.

  The acceleration voltage of the X-ray source is preferably 1 MV or more, more preferably 2 MV or more, in order to increase the generation efficiency of high-energy X-rays. Further, in order to increase the detection efficiency in the detector, it is preferably 20 MV or less, more preferably 10 MV or less.

  The irradiation step and the detection step included in the above inspection method may be started / finished at the same time, or their timings may be reversed. More specifically, for example, a large structure is irradiated with weak X-rays in advance to start the detection process, and after a certain time, the acceleration voltage of the X-ray source is set to 500 kV to 30 MV, and the irradiation process is started. Alternatively, a large structure may be irradiated with X-rays from an X-ray source having an acceleration voltage of 500 kV to 30 MV in advance, and the detection process may be started after a predetermined time.

  Examples of a method for forming the partition include, for example, machining, photolithography, and formation by a 3D printer. However, since a high-strength partition can be formed with high definition, the partition is formed by photolithography using a photosensitive paste or a 3D printer. Is preferably formed. Above all, it is preferable to form a partition mainly composed of glass by photolithography using a photosensitive glass paste, since processing of a large area is easy, tact time is short, and manufacturing cost is low.

  The partition wall mainly composed of glass is formed, for example, by coating a photosensitive paste containing glass powder on the surface of a base material to obtain a coating film, an application step, and exposing and developing the coating film to bake the partition wall. It can be formed by a pattern forming step of obtaining a previous pattern and a firing step of firing the pattern to obtain a partition pattern. In order to manufacture a partition containing glass as a main component, 50 to 100% by mass of the inorganic component contained in the glass powder-containing paste used in the coating step needs to be glass powder.

  The glass powder contained in the glass powder-containing paste is preferably glass that softens at a firing temperature, and more preferably low softening point glass having a softening temperature of 700 ° C. or lower.

  The softening temperature is determined by measuring the endothermic end temperature at the endothermic peak from the DTA curve obtained by measuring the sample using a differential thermal analyzer (for example, differential type differential thermal balance TG8120; manufactured by Rigaku Corporation) by the tangential method. It can be obtained by inserting. More specifically, first, using a differential thermal analyzer, the temperature is raised from room temperature at a rate of 20 ° C./min using alumina powder as a standard sample to measure an inorganic powder to be a measurement sample, thereby obtaining a DTA curve. Then, from the obtained DTA curve, the softening point Ts obtained by extrapolating the endothermic end temperature at the endothermic peak by the tangent method can be used as the softening temperature.

  In order to obtain a low softening point glass, a metal oxide selected from the group consisting of oxides of lead oxide, bismuth oxide, zinc oxide and alkali metal, which is an effective compound for lowering the softening point of the glass, is used. However, it is preferable to adjust the softening temperature of the glass using an alkali metal oxide. Here, the alkali metal refers to a metal selected from the group consisting of lithium, sodium and potassium.

  The proportion of the alkali metal oxide in the low softening point glass is preferably 2 to 20% by mass. When the proportion of the alkali metal oxide is less than 2% by mass, the softening temperature becomes high, and it becomes necessary to carry out the firing step at a high temperature, and defects are likely to occur in the partition walls. On the other hand, when the proportion of the alkali metal oxide exceeds 20% by mass, the viscosity of the glass is excessively reduced in the firing step, and the shape of the obtained grid-like fired pattern is likely to be distorted.

  Further, the low softening point glass preferably contains zinc oxide in an amount of 3 to 10% by mass in order to optimize the viscosity at a high temperature. When the proportion of zinc oxide in the low softening point glass is less than 3% by mass, the viscosity at high temperatures increases. On the other hand, when the content of zinc oxide exceeds 10% by mass, the production cost of the low softening point glass increases.

Further, the low softening point glass is a metal selected from the group consisting of silicon oxide, boron oxide, aluminum oxide and alkaline earth metal oxides for the purpose of adjusting stability, crystallinity, transparency, refractive index or thermal expansion characteristics. It is preferable to contain an oxide. Here, the alkaline earth metal refers to a metal selected from the group consisting of magnesium, calcium, barium, and strontium. An example of a preferable composition range of the low softening point glass is shown below.
Alkali metal oxide: 2 to 20% by mass
Zinc oxide: 3 to 10% by mass
Silicon oxide: 20 to 40% by mass
Boron oxide: 25 to 40% by mass
Aluminum oxide: 10 to 30% by mass
Alkaline earth metal oxide: 5 to 15% by mass
The particle size of the inorganic powder including the glass powder can be measured using a particle size distribution measuring device (for example, MT3300; manufactured by Nikkiso Co., Ltd.). More specifically, the measurement can be performed after charging the inorganic powder into the sample chamber of the particle size distribution measuring device filled with water and performing ultrasonic treatment for 300 seconds.

  The 50% volume average particle size (hereinafter, “D50”) of the low softening point glass powder is preferably from 1.0 to 4.0 μm. When D50 is less than 1.0 μm, the glass powder agglomerates, so that uniform dispersibility cannot be obtained, and the flow stability of the paste decreases. On the other hand, when D50 exceeds 4.0 μm, the surface irregularities of the fired pattern obtained in the firing step become large, which is likely to cause the subsequent breakage of the partition walls.

  Glass powder-containing paste, in order to control the shrinkage rate of the lattice pattern in the firing step and to maintain the shape of the partition walls finally obtained, in addition to the low softening point glass, high softening point glass whose softening temperature exceeds 700 ° C or Ceramic particles such as silicon oxide, aluminum oxide, titanium oxide or zirconium oxide may be contained as a filler. The proportion of the filler in the entire inorganic component is preferably 50% by mass or less in order to prevent a decrease in the strength of the partition walls due to the inhibition of sintering of the glass powder. D50 of the filler is preferably the same as that of the glass powder having a low softening point.

  The application step is a step of applying a glass powder-containing paste on the entire surface or a part of the surface of the base material to obtain a coating film. As the substrate, a support having high heat resistance such as a glass plate or a ceramic plate can be used. Examples of a method for applying the glass powder-containing paste include a screen printing method, a bar coater, a roll coater, a die coater, and a blade coater. The thickness of the obtained coating film can be adjusted by the number of coatings, the mesh size of the screen, the viscosity of the paste, and the like.

  The pattern formation step includes, for example, an exposure step of exposing the coating film obtained in the coating step through a photomask having a predetermined opening, and dissolving a portion of the coating film after exposure that is soluble in a developer. And a developing step of removing.

  The exposure step is a step of photo-curing a necessary portion of the coating film by exposure, or a photo-decomposition of an unnecessary portion of the coating film to make an arbitrary portion of the coating film soluble in a developer. . The developing step is a step of dissolving and removing a portion of the coating film after exposure, which is soluble in the developing solution, with the developing solution to obtain a grid-like pattern before firing in which only necessary portions remain.

In the exposure step, an arbitrary pattern may be directly drawn by a laser beam or the like without using a photomask. As the exposure apparatus, for example, a proximity exposure machine can be mentioned. The actinic rays irradiated in the exposure step include, for example, near-infrared rays, visible rays, and ultraviolet rays, with ultraviolet rays being preferred. Examples of the light source include a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a halogen lamp and a germicidal lamp, and an ultra-high-pressure mercury lamp is preferable. Although the exposure conditions vary depending on the thickness of the coating film, it is usual that the exposure is performed for 0.01 to 30 minutes using an ultra-high pressure mercury lamp having an output of 1 to 100 mW / cm ² .

  Examples of the developing method in the developing step include an immersion method, a spray method, and a brush method. As the developing solution, a solvent capable of dissolving an unnecessary portion in the coating film after exposure may be appropriately selected, and an aqueous solution containing water as a main component is preferable. For example, when the glass powder-containing paste contains a polymer having a carboxyl group, an alkaline aqueous solution can be selected as the developer. Examples of the aqueous alkali solution include, for example, an inorganic alkali aqueous solution such as sodium hydroxide, sodium carbonate or calcium hydroxide or an organic alkali aqueous solution such as tetramethylammonium hydroxide, trimethylbenzylammonium hydroxide, monoethanolamine or diethanolamine, An organic alkali aqueous solution is preferred because it is easily removed in the firing step. The concentration of the aqueous alkali solution is preferably from 0.05 to 5% by mass, more preferably from 0.1 to 1% by mass. If the alkali concentration is less than 0.05% by mass, unnecessary portions of the exposed coating film may not be sufficiently removed. On the other hand, if the alkali concentration exceeds 5% by mass, the grid-like pattern before firing may be peeled off or corroded. The development temperature is preferably 20 to 50 ° C. in order to facilitate the process control.

  In order to perform pattern formation by exposure and development, the glass powder-containing paste applied in the application step needs to be photosensitive. That is, the glass powder-containing paste needs to contain a photosensitive organic component. The proportion of the organic component in the photosensitive glass powder-containing paste is preferably from 30 to 80% by mass, and more preferably from 40 to 70% by mass. When the content of the organic component is less than 30% by mass, the dispersibility of the inorganic component in the paste is reduced, and defects are easily generated in the baking process. In addition, the paste viscosity is increased and the applicability is reduced. Stability also tends to decrease. On the other hand, if the organic component exceeds 80% by mass, the shrinkage rate of the lattice pattern in the firing step increases, and defects are likely to occur.

  The glass powder contained in the photosensitive glass powder-containing paste preferably has a softening temperature of 480 ° C. or higher in order to almost completely remove the organic components in the firing step and to secure the strength of the partition walls finally obtained. . If the softening temperature is lower than 480 ° C., the glass powder is softened before the organic components are sufficiently removed in the firing step, and the organic components remain in the sintered glass, causing the partition walls to be colored. Therefore, there is a concern that the luminance of the scintillator panel is reduced.

  In the photosensitive glass powder-containing paste, the refractive index n1 of the glass powder and the refractive index n2 of the organic component are -0.1 <in order to suppress light scattering during exposure and form a highly accurate pattern. Preferably, the relationship of n1-n2 <0.1 is satisfied, more preferably, the relationship of -0.01 ≦ n1-n2 ≦ 0.01 is satisfied, and the relationship of −0.005 ≦ n1-n2 ≦ 0.005 is satisfied. It is more preferable to satisfy the following. Note that the refractive index of the glass powder can be appropriately adjusted depending on the composition of the metal oxide contained in the glass powder.

  The refractive index of the glass powder can be measured by a Becke line detection method. Further, the refractive index of the organic component can be determined by measuring a coating film composed of the organic component by ellipsometry. More specifically, the refractive index (ng) of the glass powder or the organic component at a wavelength of 436 nm (g-line) at 25 ° C. can be n1 or n2, respectively.

  Examples of the photosensitive organic component contained in the photosensitive glass powder-containing paste include a photosensitive monomer, a photosensitive oligomer, and a photosensitive polymer. Here, the photosensitive monomer, photosensitive oligomer, or photosensitive polymer refers to a monomer, oligomer, or polymer that undergoes a reaction such as photocrosslinking or photopolymerization by irradiation with actinic light to change its chemical structure.

  As the photosensitive monomer, a compound having an active carbon-carbon unsaturated double bond is preferable. Examples of such a compound include a compound having a vinyl group, an acryloyl group, a methacryloyl group, or an acrylamide group.In order to increase the density of photocrosslinking and form a high-precision pattern, a polyfunctional acrylate compound or a polyfunctional acrylate compound is used. Functional methacrylate compounds are preferred.

  As the photosensitive oligomer or photosensitive polymer, an oligomer or polymer having an active carbon-carbon unsaturated double bond and having a carboxyl group is preferable. Such oligomers or polymers include, for example, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid or their acid anhydrides, methacrylic acid esters, acrylic acid esters Styrene, acrylonitrile, vinyl acetate or 2-hydroxyacrylate. Examples of a method of introducing an active carbon-carbon unsaturated double bond into an oligomer or a polymer include, for example, acrylic acid chloride, methacrylic acid chloride or mercapto group, amino group, hydroxyl group or carboxyl group of the oligomer or polymer. Examples thereof include a method of reacting an allyl chloride, an ethylenically unsaturated compound having a glycidyl group or an isocyanate group, or a carboxylic acid such as maleic acid.

  By using a photosensitive monomer or a photosensitive oligomer having a urethane bond, it is possible to obtain a glass powder-containing paste that can alleviate the stress in the initial stage of the firing step and that hardly causes pattern defects in the firing step.

  The photosensitive glass powder-containing paste may contain a photopolymerization initiator, if necessary. Here, the photopolymerization initiator refers to a compound that generates a radical upon irradiation with actinic light. Examples of the photopolymerization initiator include benzophenone, methyl o-benzoylbenzoate, 4,4-bis (dimethylamino) benzophenone, 4,4-bis (diethylamino) benzophenone, 4,4-dichlorobenzophenone, and 4-benzoyl- 4-methyldiphenyl ketone, dibenzyl ketone, fluorenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone , Diethylthioxanthone, benzyl, benzylmethoxyethyl acetal, benzoin, benzoin methyl ether, benzoin butyl ether, anthraquinone, 2-t-butylanthraquinone, anthrone, benzua Thorone, dibenzosuberone, methyleneanthrone, 4-azidobenzalacetophenone, 2,6-bis (p-azidobenzylidene) cyclohexanone, 2,6-bis (p-azidobenzylidene) -4-methylcyclohexanone, 1-phenyl- 1,2-butadione-2- (O-methoxycarbonyl) oxime, 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) oxime, 1,3-diphenylpropanetrione-2- (O- Ethoxycarbonyl) oxime, 1-phenyl-3-ethoxypropanetrione-2- (O-benzoyl) oxime, Michler's ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanone, -Benzyl-2-dimethylamino-1- (4-morpholinofe B) photoreducing dyes such as butanone-1, naphthalenesulfonyl chloride, quinoline sulfonyl chloride, N-phenylthioacridone, benzothiazole disulfide, triphenylphorphine, benzoin peroxide or eosin or methylene blue, and ascorbic acid or triethanol A combination of a reducing agent with an amine or the like can be given.

  When the photosensitive glass powder-containing paste contains a polymer having a carboxyl group as a photosensitive polymer, the solubility in an alkaline aqueous solution during development is improved. The acid value of the polymer having a carboxyl group is preferably from 50 to 150 mgKOH / g. When the acid value is 150 mgKOH / g or less, the development margin is widened. On the other hand, when the acid value is 50 mgKOH / g or more, the solubility in an alkaline aqueous solution does not decrease, and a high-definition pattern can be obtained.

  The photosensitive glass powder-containing paste can be obtained by blending various components so as to have a predetermined composition, and then uniformly mixing and dispersing with a three-roller or a kneader.

  The viscosity of the photosensitive glass powder-containing paste can be appropriately adjusted by the addition ratio of an inorganic powder, a thickener, an organic solvent, a polymerization inhibitor, a plasticizer or an anti-settling agent, and the range is 2 to 200 Pa.・ S is preferred. For example, when a photosensitive glass powder-containing paste is applied to a substrate by spin coating, a viscosity of 2 to 5 Pa · s is preferable, and when applied to a substrate by a blade coater method or a die coater method, A viscosity of 10 to 50 Pa · s is preferred. When a photosensitive glass powder-containing paste is applied by a single screen printing method to obtain a coating film having a thickness of 10 to 20 μm, a viscosity of 50 to 200 Pa · s is preferable.

  In the firing step, the grid-like pre-fired pattern obtained in the pattern forming step is fired to decompose and remove the organic components contained in the glass powder-containing paste, soften and sinter the glass powder, and fire the grid-like fire. This is a step of obtaining a later pattern, that is, a partition. The firing conditions vary depending on the composition of the glass powder-containing paste and the type of the base material. For example, firing can be performed in a firing furnace in an air, nitrogen, or hydrogen atmosphere. Examples of the firing furnace include a batch type firing furnace and a belt type continuous firing furnace. The firing temperature is preferably from 500 to 1000C, more preferably from 500 to 800C, and even more preferably from 500 to 700C. When the firing temperature is lower than 500 ° C., decomposition and removal of organic components become insufficient. On the other hand, if the firing temperature exceeds 1000 ° C., usable substrates are limited to high heat-resistant ceramic plates and the like. The firing time is preferably from 10 to 60 minutes.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Here, Examples 1, 3-28, and 32-33 should be read as Reference Examples, and Example 2 should be read as Comparative Examples.

(Raw material for paste containing glass powder)
The raw materials used for producing the photosensitive glass powder-containing paste are as follows.
Photosensitive monomer M-1: trimethylolpropane triacrylate Photosensitive monomer M-2: tetrapropylene glycol dimethacrylate photopolymer: copolymer having a mass ratio of methacrylic acid / methyl methacrylate / styrene = 40/40/30 Obtained by the addition reaction of 0.4 equivalent of glycidyl methacrylate to the carboxyl group of (weight average molecular weight 43000; acid value 100)
Photopolymerization initiator: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 (IC369; manufactured by BASF)
Polymerization inhibitor: 1,6-hexanediol-bis [(3,5-di-t-butyl-4-hydroxyphenyl) propionate])
UV absorbent solution: Sudan IV (manufactured by Tokyo Ohka Kogyo Co., Ltd.) 0.3% by mass of γ-butyrolactone Solution viscosity adjuster: Flownon EC121 (manufactured by Kyoeisha Chemical Co., Ltd.)
Solvent: γ-butyrolactone low softening point glass powder:
27% by mass of SiO _2, 31% by mass of B ₂ O ₃ , 6% by mass of ZnO, 7% by mass of Li ₂ O, 2% by mass of MgO, 2% by mass of CaO, 2% by mass of BaO, 23% by mass of Al ₂ O ₃ , refraction Rate (ng) 1.56, glass softening temperature 588 ° C., coefficient of thermal expansion 70 × 10 ⁻⁷ (K ⁻¹ ), average particle size 2.3 μm
High softening point glass powder:
SiO ₂ 30% by mass, B ₂ O ₃ 31% by mass, ZnO 6% by mass, MgO 2% by mass, CaO 2% by mass, BaO 2% by mass, Al ₂ O ₃ 27% by mass, refractive index (ng) 1.55 790 ° C., coefficient of thermal expansion 32 × 10 ⁻⁷ (K ⁻¹ ), average particle size 2.3 μm
(Preparation of paste containing glass powder)
4 parts by weight of photosensitive monomer M-1, 6 parts by weight of photosensitive monomer M-2, 24 parts by weight of photosensitive polymer, 6 parts by weight of photopolymerization initiator, 0.2 parts by weight of polymerization inhibitor and 12 parts by weight 8.8 parts by mass of the ultraviolet absorbent solution was heated and dissolved at a temperature of 80 ° C. in 38 parts by mass of a solvent. After cooling the obtained solution, 9 parts by mass of a viscosity modifier was added to obtain an organic solution 1. The refractive index (ng) of the organic coating film obtained by applying the obtained organic solution 1 to a glass plate and drying was 1.555.

  To 50 parts by mass of the organic solution 1, 40 parts by mass of a low softening point glass powder and 10 parts by mass of a high softening point glass powder were added, followed by kneading with a three-roller kneader to obtain a glass powder-containing paste. .

(Raw material of phosphor paste)
Phosphor 1: Terbium-doped gadolinium oxysulfide phosphor having an average particle diameter of 10 μm 2: Terbium-doped gadolinium oxysulfide phosphor having an average particle diameter of 2 μm 3: Terbium-doped oxysulfide having an average particle diameter of 5 μm Gadolinium phosphor 4: terbium-doped gadolinium oxysulfide having an average particle diameter of 30 μm Binder: 7 cp Ethocel (registered trademark) (generic name: ethylcellulose; manufactured by Nisshinsei Co., Ltd.)
Solvent: Terpineol (Preparation of phosphor paste)
The phosphor paste 1 was obtained by stirring 85 parts by mass of the phosphor 1, 3 parts by mass of the binder and 12 parts by mass of the solvent.

  Further, 85 parts by mass of the phosphor 2, 3 parts by mass of the binder and 12 parts by mass of the solvent were stirred to obtain a phosphor paste 2.

  Further, 85 parts by mass of the phosphor 3, 3 parts by mass of the binder and 12 parts by mass of the solvent were stirred to obtain a phosphor paste 3.

  Further, 85 parts by mass of the phosphor 4, 3 parts by mass of the binder and 12 parts by mass of the solvent were stirred to obtain a phosphor paste 4.

  Further, 10 parts by mass of the phosphor 1, 3 parts by mass of the binder and 87 parts by mass of the solvent were stirred to obtain a phosphor paste 5.

  Further, 42 parts by mass of the phosphor 1, 3 parts by mass of the binder and 55 parts by mass of the solvent were stirred to obtain a phosphor paste 6.

(Raw layer paste raw material)
Metal oxide 1: Titanium oxide metal oxide having an average particle diameter of 0.25 μm 2: Zirconium oxide metal oxide having an average particle diameter of 0.3 μm 3: Aluminum oxide metal oxide having an average particle diameter of 0.2 μm 4: Average particle diameter 0.5 μm barium oxide metal oxide 5: gadolinium oxide metal oxide with an average particle diameter of 0.5 μm 6: bismuth oxide metal oxide with an average particle diameter of 0.3 μm 7: lead oxide metal oxide with an average particle diameter of 0.25 μm Product 8: Cobalt oxide binder having an average particle size of 0.2 μm: 100 cp Ethocel (registered trademark) (generic name: ethyl cellulose; manufactured by Nisshinseisei)
Solvent: Terpineol (Preparation of reflective layer paste)
9 parts by mass of metal oxide 1 was added to an organic solution obtained by heating and dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C. and kneaded to obtain a reflective layer paste 1.

  Further, 9 parts by mass of metal oxide 2 was added to an organic solution obtained by heating and dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C., and kneaded to obtain a reflective layer paste 2.

  Further, 9 parts by mass of the metal oxide 3 was added to an organic solution obtained by heating and dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C., and kneaded to obtain a reflective layer paste 3.

  Further, 9 parts by mass of metal oxide 4 was added to an organic solution obtained by heating and dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C. and kneaded to obtain a reflective layer paste 4.

  Further, 9 parts by mass of a metal oxide 5 was added to an organic solution obtained by heating and dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C. and kneaded to obtain a reflective layer paste 5.

  Further, 9 parts by mass of metal oxide 6 was added to an organic solution obtained by heating and dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C. and kneaded to obtain a reflective layer paste 6.

  Further, 9 parts by mass of a metal oxide 7 was added to an organic solution obtained by heating and dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C. and kneaded to obtain a reflective layer paste 7.

  Further, 9 parts by mass of a metal oxide 8 was added to an organic solution obtained by heating and dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C. and kneaded to obtain a reflective layer paste 8.

  Further, 0.9 parts by mass of the metal oxide 1 was added to an organic solution obtained by heating and dissolving 0.1 parts by mass of a binder in 99 parts by mass of an organic solvent at 80 ° C., and kneaded. Obtained.

  In addition, 2.7 parts by mass of metal oxide 1 was added to an organic solution obtained by heating and dissolving 0.3 parts by mass of a binder in 97 parts by mass of an organic solvent at 80 ° C., and kneaded. Obtained.

  Further, 18 parts by mass of the metal oxide 1 was added to an organic solution obtained by heating and dissolving 2 parts by mass of a binder in 80 parts by mass of an organic solvent at 80 ° C., and kneaded to obtain a reflective layer paste 11.

  Further, 27 parts by mass of the metal oxide 1 was added to an organic solution obtained by heating and dissolving 3 parts by mass of a binder in 70 parts by mass of an organic solvent at 80 ° C., and kneaded to obtain a reflective layer paste 12.

  Further, 45 parts by mass of the metal oxide 1 was added to an organic solution obtained by heating and dissolving 5 parts by mass of a binder in 50 parts by mass of an organic solvent at 80 ° C., and kneaded to obtain a reflective layer paste 13.

(Formation of partition)
As a base material, a 125 mm × 125 mm × 0.7 mm soda glass plate was used. The glass powder-containing paste was applied to the surface of the base material with a die coater so that the thickness after drying became a desired thickness, and dried to obtain a coating film of the glass powder-containing paste. Next, the coating film of the paste containing the glass powder was exposed to light using an ultrahigh-pressure mercury lamp through a photomask having an opening corresponding to a desired pattern. The exposed coating film was developed in a 0.5% by mass aqueous ethanolamine solution to remove unexposed portions to obtain a grid-like pattern before firing. The obtained grid-like pattern before firing was fired in air at 585 ° C. for 15 minutes to form a grid-like partition wall mainly composed of glass.

(Evaluation of reflectance)
The SCI reflectance at a wavelength of 530 nm was measured using a spectrophotometer (CM-2600d; manufactured by Konica Minolta).

(Evaluation of brightness and sharpness)
Using a radiation detector in which a scintillator panel and an output board are attached to each other, an X-ray transmission inspection is performed on reinforced concrete having a thickness of 30 cm when X-rays are irradiated for a certain period of time. Was evaluated for sharpness from the clarity of the reinforcing bars reflected in the captured image. Both luminance and sharpness were visually evaluated on a five-point scale, and the best case was determined as A, and B, C, D, and E were determined in the order of goodness. When the sharpness is E, it is highly likely that the sharpness becomes unsuitable as a radiation detector constituting the inspection apparatus for large structures of the present invention.

(Example 1)
In the partition wall forming operation, the glass powder-containing paste was applied so that the thickness after drying became 1.5 mm. For the exposure, a chromium mask having a grid-like opening having a pitch of 0.5 mm and an opening width of 0.03 mm was used. The porosity of the obtained partition wall was 2.5%, the partition wall height L1 was 1 mm, the partition wall interval L2 was 0.5 mm, the partition wall bottom width L3 was 0.05 mm, and the partition wall top width L4 was 0.03 mm. there were. The reflectance of the substrate on which the obtained partition wall was formed was 15%.

  The substrate on which the grid-like partition walls were formed was set in a vacuum printer, and the phosphor paste 1 was printed to completely fill the cells with the phosphor paste. Then, it dried at 150 degreeC for 60 minutes, and obtained the scintillator panel 1. The cross section of the scintillator panel, which is perpendicular to the substrate, was exposed by a polishing device, the cross section was observed with a scanning electron microscope, and the average primary particle diameter of the phosphor calculated by image processing was 10 μm.

  The obtained scintillator panel 1 was aligned on an output substrate having a resolution of 0.5 mm pitch so that cells and pixels corresponded one-to-one, and then bonded to each other to obtain a radiation detector 1. When the brightness and sharpness of the radiation detector 1 were evaluated using an X-ray source with an acceleration voltage of 1 MV, the brightness was C and the sharpness was C, and both were good.

(Example 2)
In the same manner as in Example 1, a substrate on which a partition was formed was produced. The substrate was set in a vacuum printer, and the reflective layer paste 9 was printed to completely fill the cells with the reflective layer paste. Thereafter, drying was performed at 90 ° C. for 60 minutes to form a reflection layer on the surfaces of the substrate and the partition walls. The average thickness of the reflective layer was 2 μm, and the reflectance of the substrate after the formation of the reflective layer was 20%. After that, a phosphor paste was filled in the same manner as in Example 1 to obtain a scintillator panel 2, which was then aligned with an output substrate and then bonded to obtain a radiation detector 2. The luminance of the radiation detector 2 was C and the sharpness was C, and all were good.

(Example 3)
A radiation detector 3 was obtained in the same manner as in Example 2, except that the reflective layer paste 10 was used as the reflective layer paste. The average thickness of the reflection layer was 5 μm, the reflectance of the substrate after the formation of the reflection layer was 25%, the luminance of the radiation detector 3 was C, and the sharpness was B. All were good.

(Example 4)
A radiation detector 4 was obtained in the same manner as in Example 2, except that the reflective layer paste 1 was used as the reflective layer paste. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate after the formation of the reflection layer was 60%, the luminance of the radiation detector 4 was B, and the sharpness was B. All were good.

(Example 5)
A radiation detector 5 was obtained in the same manner as in Example 2, except that the reflective layer paste 12 was used as the reflective layer paste. The average thickness of the reflection layer was 50 μm, the reflectance of the substrate after the formation of the reflection layer was 85%, the luminance of the radiation detector 5 was B, and the sharpness was C. All were good.

(Example 6)
A radiation detector 5 was obtained in the same manner as in Example 2, except that the reflective layer paste 13 was used as the reflective layer paste. The average thickness of the reflection layer was 80 μm, the reflectance of the substrate after the formation of the reflection layer was 90%, and the luminance of the radiation detector 5 was C, which was good. The sharpness was D, which was relatively good.

(Example 7)
A scintillator panel 7 was obtained in the same manner as in Example 4, except that a chromium mask having a lattice-shaped opening with a pitch of 0.2 mm and an opening width of 0.02 mm was used for the formation of the partition walls. The porosity of the obtained partition was 2%, the height L1 of the partition was 1 mm, the interval L2 of the partition was 0.2 mm, the bottom width L3 of the partition was 0.04 mm, and the top width L4 of the partition was 0.02 mm. . The average thickness of the reflective layer was 20 μm, and the reflectance of the substrate after the formation of the reflective layer was 40%.

  The obtained scintillator panel 7 was aligned on an output substrate having a resolution of 0.2 mm pitch so that cells and pixels corresponded one to one, and then bonded to each other to obtain a radiation detector 7. The brightness of the radiation detector 7 was C and the sharpness was A, and all were good.

(Example 8)
In forming the partition walls, a scintillator panel 8 was obtained in the same manner as in Example 4, except that a chromium mask having a grid-like opening having a pitch of 1 mm and an opening width of 0.04 mm was used for exposure. The porosity of the obtained partition was 3%, the height L1 of the partition was 1 mm, the interval L2 of the partition was 1 mm, the bottom width L3 of the partition was 0.08 mm, and the top width L4 of the partition was 0.04 mm. The average thickness of the reflective layer was 20 μm, and the reflectance of the substrate after the formation of the reflective layer was 70%.

  The scintillator panel 8 thus obtained was aligned on an output substrate having a resolution of 1 mm pitch so that the cells and the pixels corresponded to each other, and then bonded to each other to obtain a radiation detector 8. The brightness of the radiation detector 8 was A and the sharpness was C, and all were good.

(Example 9)
Aluminum was sputtered on the substrate on which the grid-like partition walls were formed in the same manner as in Example 4 to form a shielding layer. The average thickness of the shielding layer was 1 μm. Thereafter, similarly to Example 4, a reflection layer was formed, a phosphor paste was filled, and the resultant was bonded to an output substrate to obtain a radiation detector 9. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate on which the partition walls were formed was 45%, the luminance of the radiation detector 9 was C, and the sharpness was A, and all were good.

(Example 10)
A radiation detector 10 was obtained in the same manner as in Example 9, except that the reflective layer paste 11 was used as the reflective layer paste. The average thickness of the reflection layer was 30 μm, the reflectance of the substrate after the formation of the reflection layer was 55%, the luminance of the radiation detector 10 was B, and the sharpness was A, and all were good.

(Example 11)
A radiation detector 11 was obtained in the same manner as in Example 9, except that the reflective layer paste 12 was used as the reflective layer paste. The average thickness of the reflection layer was 50 μm, the reflectance of the substrate after the formation of the reflection layer was 65%, the luminance of the radiation detector 11 was C, and the sharpness was B. All were good.

(Example 12)
A radiation detector 12 was obtained in the same manner as in Example 9, except that the reflective layer paste 13 was used as the reflective layer paste. The average thickness of the reflection layer was 80 μm, the reflectance of the substrate after the formation of the reflection layer was 65%, the luminance of the radiation detector 12 was C, and the sharpness was C. All were good.

(Example 13)
38 parts by mass of a tungsten powder (particle size: 1 μm) was added to an organic solution obtained by heating and dissolving 2 parts by mass of a binder (100 cP ethocell) in 60 parts by mass of an organic solvent (terpineol) at 80 ° C., and kneaded. A line absorbing layer paste was obtained. The substrate on which the grid-shaped partition walls were formed in the same manner as in Example 4 was set in a vacuum printer, and the X-ray absorbing layer paste was printed to completely fill the cells with the X-ray absorbing layer paste. Thereafter, drying was performed at 90 ° C. for 60 minutes to form an X-ray absorbing layer on the surfaces of the substrate and the partition walls. The average thickness of the X-ray absorbing layer was 10 μm. Thereafter, similarly to Example 4, a reflection layer was formed, filled with a phosphor paste, and bonded to an output substrate to obtain a radiation detector 12. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate after the formation of the reflection layer was 40%, the luminance of the radiation detector 13 was C, and the sharpness was A, and all were good.

(Example 14)
A radiation detector 14 was obtained in the same manner as in Example 2, except that the reflective layer paste 2 was used as the reflective layer paste. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate after the formation of the reflection layer was 55%, the luminance of the radiation detector 14 was B, and the sharpness was B. All were good.

(Example 15)
A radiation detector 15 was obtained in the same manner as in Example 2, except that the reflective layer paste 3 was used as the reflective layer paste. The average thickness of the reflection layer was 25 μm, the reflectance of the substrate after the formation of the reflection layer was 40%, the luminance of the radiation detector 15 was C, and the sharpness was B, and all were good.

(Example 16)
A radiation detector 16 was obtained in the same manner as in Example 2, except that the reflective layer paste 4 was used as the reflective layer paste. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate after the formation of the reflection layer was 45%, the luminance of the radiation detector 16 was B, and the sharpness was B. All were good.

(Example 17)
A radiation detector 17 was obtained in the same manner as in Example 2, except that the reflective layer paste 5 was used as the reflective layer paste. The average thickness of the reflection layer was 15 μm, the reflectance of the substrate after the formation of the reflection layer was 55%, the luminance of the radiation detector 17 was B, and the sharpness was A. All were good.

(Example 18)
A radiation detector 18 was obtained in the same manner as in Example 2, except that the reflective layer paste 6 was used as the reflective layer paste. The average thickness of the reflection layer was 15 μm, the reflectance of the substrate after the formation of the reflection layer was 30%, the luminance of the radiation detector 18 was C, and the sharpness was B. All were good.

(Example 19)
A radiation detector 19 was obtained in the same manner as in Example 2, except that the reflective layer paste 7 was used as the reflective layer paste. The average thickness of the reflection layer was 15 μm, the reflectance of the substrate after the formation of the reflection layer was 20%, and the luminance of the radiation detector 19 was D, which was relatively good. The sharpness was B, which was good.

(Example 20)
A radiation detector 20 was obtained in the same manner as in Example 2, except that the reflective layer paste 8 was used as the reflective layer paste. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate after the formation of the reflection layer was 5%, and the luminance of the radiation detector 20 was E, but the sharpness was B, which was good.

(Example 21)
A radiation detector 21 was obtained in the same manner as in Example 9, except that the phosphor paste 2 was used as the phosphor paste. The average primary particle diameter of the phosphor was 2 μm. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate after the formation of the reflection layer was 45%, and the luminance of the radiation detector 21 was D, which was relatively good. The sharpness was A, which was good.

(Example 22)
A radiation detector 22 was obtained in the same manner as in Example 9, except that the phosphor paste 3 was used as the phosphor paste. The average primary particle diameter of the phosphor was 5 μm. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate after the formation of the reflection layer was 45%, the luminance of the radiation detector 22 was C, and the sharpness was A, and all were good.

(Example 23)
A radiation detector 23 was obtained in the same manner as in Example 9, except that the phosphor paste 4 was used as the phosphor paste. The average primary particle diameter of the phosphor was 30 μm. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate after the formation of the reflection layer was 45%, the brightness of the radiation detector 23 was B, and the sharpness was A, and all were good.

(Example 24)
As a phosphor, a sintered body ingot of terbium-doped gadolinium oxysulfide was machined into a 0.9 × 0.3 × 0.3 mm columnar rectangular parallelepiped, and inserted into each cell one by one to form a phosphor layer. A radiation detector 24 was obtained in the same manner as in Example 9, except that the radiation detector 24 was formed. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate after the formation of the reflection layer was 45%, the luminance of the radiation detector 24 was C, and the sharpness was C. All were good.

(Example 25)
A radiation detector 25 was obtained in the same manner as in Example 4, except that the paste containing glass powder was applied so that the thickness after drying became 3 mm in forming the partition walls. The porosity of the obtained partition wall was 2.5%, the partition wall height L1 was 2 mm, the partition wall interval L2 was 0.5 mm, the partition wall bottom width L3 was 0.07 mm, and the partition wall top width L4 was 0.03 mm. there were. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate after the formation of the reflection layer was 45%, the luminance of the radiation detector 25 was A, and the sharpness was B, and all were good.

(Example 26)
A radiation detector 26 was obtained in the same manner as in Example 4, except that the glass powder-containing paste was applied so that the thickness after drying became 1 mm in forming the partition walls. The porosity of the obtained partition was 2%, the height L1 of the partition was 0.5 mm, the interval L2 of the partition was 0.5 mm, the bottom width L3 of the partition was 0.04 mm, and the top width L4 of the partition was 0.03 mm. there were. The average thickness of the reflection layer was 20 μm, the reflectance of the substrate after the formation of the reflection layer was 70%, the luminance of the radiation detector 26 was C, and the sharpness was B, and all were good.

(Example 27)
A radiation detector 27 was obtained in the same manner as in Example 4, except that in forming the partition walls, the paste containing glass powder was applied so that the thickness after drying became 0.4 mm. The porosity of the obtained partition is 1.5%, the height L1 of the partition is 0.2 mm, the interval L2 of the partition is 0.5 mm, the bottom width L3 of the partition is 0.03 mm, and the top width L4 of the partition is 0. 03 mm. The average thickness of the reflective layer is 25 μm, the reflectance of the substrate after the reflective layer is formed is 75%, the luminance of the radiation detector 27 is D, the sharpness is D, and both the luminance and the sharpness are low because the partition walls are low. Although slightly lower, all were relatively good.

(Example 28)
The radiation detector 4 was evaluated by using an X-ray source having an acceleration voltage of 0.5 MV in the evaluation of brightness and sharpness. The brightness was D and the sharpness was B, all of which were good.

(Example 29)
In the formation of the phosphor layer, as in Example 2, the substrate on which the grid-like partition walls and the reflective layer were formed was set in a vacuum printer, and a 0.2 mm square opening having a pitch of 0.5 mm was placed thereon. After arranging a metal mask arranged in a checkerboard pattern and performing alignment so that the opening of the metal mask and the opening of the cell defined by the partition are aligned, the phosphor paste 5 is printed, The phosphor paste 5 was completely filled in the target cell. Next, after shifting the metal mask by 0.5 mm and performing the same alignment, the phosphor paste 1 was printed, and the target cell was completely filled with the phosphor paste 1. Thereafter, drying was performed at 150 ° C. for 60 minutes to obtain a scintillator panel 29 having the same configuration as the schematic diagram of FIG. The ratio of the X-ray absorption P of the cell filled with the phosphor paste 1 to the X-ray absorption Q of the cell filled with the phosphor paste 5, P / Q, was 10.

  The scintillator panel 29 was aligned on an output substrate having a resolution of 0.5 mm pitch and then bonded to obtain a radiation detector 29. An X-ray transmission inspection was performed using a radiation detector 29 when irradiating X-rays from an X-ray source with an acceleration voltage of 1 MV to reinforced concrete having a thickness of 30 cm. Calculation for obtaining only the intensity of high-energy X-rays, that is, straight X-rays, that is, calculation for subtracting the signal of the cell filled with the phosphor paste 5 from the signal of the cell filled with the phosphor paste 1 after multiplying by an appropriate coefficient. Then, for the cell filled with the phosphor paste 5, a transmission image complemented by the average value of the four upper, lower, left and right signals was constructed, and the luminance was C and the sharpness was B. Was.

(Example 30)
In Example 29, a metal mask in which openings of 0.2 mm square were arranged in a grid pattern with a pitch of 2 mm was used as a metal mask used for printing the phosphor paste 5 in forming the phosphor layer. The phosphor paste 1 was aligned and filled using a metal mask designed to be printed only on cells other than the cells filled with the phosphor paste 5. Thereafter, drying was performed at 150 ° C. for 60 minutes to obtain a scintillator panel 30 having the same configuration as that of the schematic diagram of FIG. The ratio of the X-ray absorption P of the cell filled with the phosphor paste 1 to the X-ray absorption Q of the cell filled with the phosphor paste 5, P / Q, was 10.

  Thereafter, evaluation was performed in the same manner as in Example 29. The brightness was C and the sharpness was A, all of which were good.

(Example 31)
The same evaluation was performed in Example 30 except that the phosphor paste 6 was used instead of the phosphor paste 5. The ratio of the X-ray absorption rate P of the cell filled with the phosphor paste 1 to the X-ray absorption rate Q of the cell filled with the phosphor paste 6, P / Q, was 2. The luminance was C and the sharpness was B, all of which were good.

(Example 32)
A radiation detector 32 was obtained in the same manner as in Example 5, except that the drying temperature after printing of the reflective layer paste 12 was 160 ° C. The average thickness of the reflective layer was 50 μm, the reflectance of the substrate after the reflective layer was formed was 85%, the luminance of the radiation detector 32 was B, and the sharpness was B. The sharpness was improved as compared with the radiation detector 5. .

  When the thickness of the reflection layer of the scintillator panel constituting the radiation detector 5 and the radiation detector 32 was analyzed in detail, in the radiation detector 5, the average thickness of the reflection layer in the upper half of the cell was 45 μm, The average thickness of the reflective layer in the lower half was 55 μm, and the average thickness of the reflective layer in the upper half of the cell was smaller than the average thickness of the reflective layer in the lower half of the cell. In the detector 32, the average thickness of the reflective layer in the upper half of the cell is 60 μm, the average thickness of the reflective layer in the lower half of the cell is 40 μm, and the average thickness of the reflective layer in the upper half of the cell is: It was larger than the average thickness of the reflective layer in the lower half of the cell.

(Example 33)
A radiation detector 33 was obtained in the same manner as in Example 12, except that the drying temperature of the reflective layer paste 13 after printing was 160 ° C. The average thickness of the reflective layer was 80 μm, the reflectance of the substrate after the reflective layer was formed was 75%, the luminance of the radiation detector 33 was C, and the sharpness was B. The sharpness was improved as compared with the radiation detector 12. .

  When the thickness of the reflective layer of the scintillator panel constituting the radiation detector 12 and the radiation detector 33 was analyzed in detail, in the radiation detector 12, the average thickness of the reflective layer in the upper half of the cell was 75 μm, The average thickness of the reflective layer in the lower half was 85 μm, and the average thickness of the reflective layer in the upper half of the cell was smaller than the average thickness of the reflective layer in the lower half of the cell. In the detector 32, the average thickness of the reflective layer in the upper half of the cell is 90 μm, the average thickness of the reflective layer in the lower half of the cell is 75 μm, and the average thickness of the reflective layer in the upper half of the cell is: It was larger than the average thickness of the reflective layer in the lower half of the cell.

(Comparative Example 1)
As a base material, a 125 mm × 125 mm × 0.7 mm soda glass plate was used. The phosphor paste 1 was applied to the surface of the base material with a die coater so that the thickness after drying became 1.5 mm, and dried, whereby a scintillator panel 2 was obtained. The obtained scintillator panel 2 was bonded to an output substrate having a resolution of 0.25 mm pitch to obtain a radiation detector 31. Using the radiation detector 31, an X-ray transmission inspection was performed when irradiating X-rays from an X-ray source with an acceleration voltage of 1 MV to reinforced concrete having a thickness of 30 cm. The brightness of the obtained image was A and the sharpness was E, and the sharpness was extremely low.

(Comparative Example 2)
Evaluation was performed in the same manner as in Comparative Example 1, except that the phosphor layer was applied so as to have a thickness of 1 mm after drying and dried. The brightness of the obtained image was A and the sharpness was E, and the sharpness was extremely low.

(Comparative Example 3)
Evaluation was performed in the same manner as in Comparative Example 1, except that the phosphor layer was applied so as to have a thickness of 0.2 mm after drying and dried. The brightness of the obtained image was D and the sharpness was E, and the sharpness was extremely low.

(Comparative Example 4)
The radiation detector 31 was evaluated using an X-ray source having an acceleration voltage of 0.5 MV in evaluating the brightness and sharpness. The brightness of the obtained image was C and the sharpness was E, and the sharpness was extremely low.

(Comparative Example 5)
The radiation detector 4 was evaluated using an X-ray source having an acceleration voltage of 0.2 MV in evaluation of brightness and sharpness, but no image was obtained. This is presumably because the X-ray permeability was too low and the concrete did not transmit X-rays.

  From the above results, it is apparent that the inspection apparatus for large structures according to the present invention contributes to remarkable improvement in image sharpness in nondestructive inspection.

REFERENCE SIGNS LIST 1 radiation detector 2 scintillator panel 3 output substrate 4 substrate 5 partition 6 phosphor layer 7 diaphragm layer 8 photoelectric conversion layer 9 output layer 10 substrate 11 power supply unit 12 shielding layer 13 reflection layer

  INDUSTRIAL APPLICABILITY The present invention can be effectively used for nondestructive inspection of large structures.

Claims (9)

An irradiation function for irradiating a large structure with X-rays from an X-ray source having an acceleration voltage of 500 kV to 30 MV,
An X-ray transmitted through the large structure, a radiation detector, and a detection function, comprising: a large structure inspection device, wherein the radiation detector is a substrate, mounted on the substrate Comprising a scintillator panel made of a phosphor layer filled in cells partitioned by the partition,
The phosphor layer is composed of a plurality of modes having different compositions and / or thicknesses for each cell ,
When the X-ray absorptivity in the phosphor layer having the largest X-ray absorptivity is P and the X-ray absorptivity in the phosphor layer having the smallest X-ray absorptivity is Q, P / Q ≧ 1.5 Inspection equipment for large structures that satisfies the above relationship.   The inspection apparatus for a large structure according to claim 1, wherein the reflectance of the substrate and the partition placed on the substrate is 25 to 85%.   The inspection apparatus for a large structure according to claim 1, wherein the scintillator panel has a reflection layer between the partition and the phosphor layer, and the reflection layer contains a metal oxide.   The inspection device for a large structure according to claim 3, wherein the average thickness of the reflection layer is 5 to 50 m.   The inspection apparatus for a large structure according to claim 3, wherein the metal oxide is a compound selected from the group consisting of titanium oxide, zirconium oxide, aluminum oxide, barium oxide, bismuth oxide, and gadolinium oxide.   The inspection of a large structure according to any one of claims 3 to 5, wherein an average thickness of the reflective layer in an upper half of the cell is larger than an average thickness of the reflective layer in a lower half of the cell. apparatus.   The inspection device for a large structure according to any one of claims 1 to 6, wherein the phosphor layer contains a granular phosphor, and the phosphor has an average primary particle diameter of 1 to 50 µm.   The inspection of a large structure according to any one of claims 1 to 7, wherein the scintillator panel has a shielding layer between the partition wall and the phosphor layer, and the shielding layer contains a metal. apparatus.   The inspection device for a large structure according to any one of claims 1 to 8, wherein a height of the partition wall is 0.4 to 50 mm.