Radiation detection panel and method for manufacturing radiation detection panel

Abstract

This radiation detection panel is provided with: a photoelectric conversion substrate (2) having a plurality of photoelectric conversion units (2b); a scintillator layer (5) provided on the photoelectric conversion substrate (2) and having one surface (5a) facing the photoelectric conversion substrate (2) and another surface (5b) located on the opposite side from the one surface (5a); and a reflective layer (6) that is provided on the other surface (5b) and is formed from an adhesive (61) and light scattering particles (62), the reflective layer (6) having an opposing surface (63) that opposes the other surface (5b), and an uneven surface (64) that is positioned on the opposite side from the opposing surface (63), the uneven surface (64) comprising a surface of a plurality of protrusions (64a) and a surface of a plurality of recesses (64b), each of the plurality of protrusions (64a) has a protrusion (64a) adjacent to each of the plurality of protrusions (64a), and an interval from each of the plurality of protrusions (64a) to the adjacent protrusion (64a) is random.

Description

Technical Field

[0001] Embodiments of the present invention relate to a radiation detection panel and a method of manufacturing the same. Background Art

[0002] One example of a radiation detector includes an X-ray detector. The X-ray detector has a photoelectric conversion substrate on which a plurality of photoelectric conversion elements are arranged in a lattice pattern, a scintillator layer provided on the photoelectric conversion substrate, and a reflective layer formed on the scintillator layer. The reflective layer is known to be formed by applying a mixed material of a resin-based adhesive, light-scattering particles, and a solvent onto the scintillator layer using a dispenser and drying the applied mixed material. Prior Art Documents Patent Documents

[0003] Patent Document 1: Japanese Patent Laid-Open No. 2010-145351 Summary of the Invention Technical Problem to be Solved by the Invention

[0004] The present embodiment provides a radiation detection panel and a method of manufacturing the same that can improve the quality of the detected image. Technical Means for Solving the Technical Problem

[0005] A radiation detection panel according to an embodiment includes: a photoelectric conversion substrate having a plurality of photoelectric conversion portions that convert fluorescence into an electric signal; a scintillator layer provided on the photoelectric conversion substrate, having one surface facing the photoelectric conversion substrate and another surface on the opposite side of the one surface, and converting radiation into fluorescence; and a reflective layer provided on the another surface, formed of an adhesive and light-scattering particles, and reflecting the fluorescence generated by the scintillator layer toward the plurality of photoelectric conversion portions. The reflective layer includes a facing surface facing the another surface and an uneven surface on the opposite side of the facing surface. The uneven surface includes surfaces of a plurality of convex portions protruding in a direction away from the scintillator layer and surfaces of concave portions that are more recessed than the plurality of convex portions. Each of the plurality of convex portions includes a convex portion adjacent to each of the plurality of convex portions, and the interval from each of the plurality of convex portions to the adjacent convex portion is random.

[0006] In addition, in a method for manufacturing a radiation detection panel according to an embodiment, a photoelectric conversion substrate having a plurality of photoelectric conversion portions that convert incident fluorescence into an electric signal is prepared. A scintillator layer is formed on the photoelectric conversion substrate. The scintillator layer has one surface facing the photoelectric conversion substrate and another surface located on the opposite side of the one surface, and converts radiation into fluorescence. A first mixed material formed of an adhesive, light-scattering particles, and a solvent for dissolving the adhesive is prepared. By processing the first mixed material into a plurality of particles, a plurality of second mixed materials are formed. The plurality of second mixed materials are particles formed of the adhesive, the light-scattering particles, and the solvent respectively. The plurality of second mixed materials are scattered on the another surface. By drying the plurality of second mixed materials scattered on the another surface, a reflective layer that reflects the fluorescence generated by the scintillator layer toward the plurality of photoelectric conversion portions is formed. Description of the Drawings

[0007] Figure 1 is a cross-sectional view showing an X-ray detector according to an embodiment. Figure 2 is a perspective view showing a support substrate, an X-ray detection panel, a circuit board, and a plurality of FPCs of the X-ray detector according to the above embodiment, and is a view showing an image transmission portion together. Figure 3 is an enlarged cross-sectional view showing a part of an X-ray detection module of the X-ray detector according to the above embodiment. Figure 4 is showing Figure 3 an enlarged cross-sectional view of one of the plurality of mixtures shown. Figure 5 is a top view showing a part of a reflective layer of the X-ray detector according to the above embodiment, and is a view observed from the moisture-proof cover side. Figure 6 is along Figure 5 the A-A line of. Figure 7 is along Figure 5 the B-B line of. Figure 8 is Figure 6 a top view of the arrow C of, and is a view showing a part of the opposite surface in the reflective layer. Figure 9 is a top view showing an X-ray detection module of the X-ray detector according to the above embodiment. Figure 10 is along Figure 9 the line D-D of the X-ray detection module. Figure 11It is a cross-sectional view showing an example when forming a reflective layer in the X-ray detection panel of the above-described embodiment. Detailed Embodiment

[0008] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the present disclosure is merely an example, and appropriate modifications that are easily conceivable by those skilled in the art while maintaining the gist of the present invention are naturally included in the scope of the present invention. For a more explicit description, in the drawings, the widths, thicknesses, shapes, etc. of each part are sometimes schematically shown compared with the actual manner, but this is only an example and cannot be used to limit the interpretation of the present invention. Furthermore, in this specification and each drawing, the same reference numerals are assigned to the same elements as those described above, and detailed descriptions are appropriately omitted.

[0009] First, the basic concept of the embodiment of the present invention will be described. As a radiation detector, for example, there is an X-ray detector. An X-plane detector using an active matrix method has been developed as an X-ray detector. The X-ray detector includes an X-ray detection panel as a radiation detection panel. The X-ray detection panel includes a scintillator layer, a photoelectric conversion substrate, etc. The photoelectric conversion substrate includes a substrate formed of glass and a circuit layer formed on the substrate having a photoelectric conversion portion, wirings, etc. The photoelectric conversion portion includes photoelectric conversion elements such as amorphous silicon (a-Si) photodiodes and CCDs (charge-coupled devices).

[0010] The scintillator layer is formed above the photoelectric conversion portion. The material of the scintillator layer is, for example, thallium-activated cesium iodide. The scintillator layer can be formed by using cutting to form grooves or deposition by a vacuum evaporation method, etc., so as to improve the resolution characteristics. The X-ray detector outputs a digital signal of an X-ray radiographic image or a real-time X-ray image by detecting the irradiated X-ray. Specifically, the X-ray detector converts the incident X-ray into fluorescence as visible light through the scintillator layer as a fluorescence converter, and converts the above fluorescence into an electrical signal through the photoelectric conversion element, thereby obtaining an X-ray image as a digital signal.

[0011] A sealing portion is provided around the scintillator layer. The sealing portion is formed of a thermoplastic resin mainly composed of polypropylene. In addition, the scintillator layer is covered with a moisture-proof cover. For the purpose of preventing the scintillator layer from deteriorating due to moisture in the atmosphere, a moisture-proof cover is provided. The moisture-proof cover has a laminated structure of, for example, a metal layer formed of aluminum or the like and a resin layer formed of PET or the like. In addition, the moisture-proof cover is joined to the sealing portion. The scintillator layer is located in a space sealed by the photoelectric conversion substrate, the sealing portion, and the moisture-proof cover.

[0012] The X-ray detection panel further includes a reflective layer. The reflective layer is located between the scintillator layer and the moisture-proof cover. The reflective layer is provided to improve the utilization efficiency of the fluorescence from the scintillator layer and to improve the sensitivity characteristics of the X-ray detector. The reflective layer is used to reflect the fluorescence toward the opposite side of the photoelectric conversion section, thereby increasing the fluorescence reaching the photoelectric conversion section. It is known to form the reflective layer by the following methods: a method of forming a metal film with a high fluorescence reflectivity such as silver (Ag) alloy or aluminum on the scintillator layer, or a method of coating a mixed material (paste material) formed of an adhesive or light-scattering particles or the like by a dispenser. The viscosity of the above-mentioned mixed material is, for example, 2000 MPa·s. In the case of forming the reflective layer by coating the mixed material, the reflective layer is formed by drying the coated mixed material. At this time, the mixed material is compressed, and the scintillator layer may be peeled off due to the tensile stress caused by this compression. In addition, the X-ray detection panel may be deformed.

[0013] In addition, the reflective layer formed by coating the mixed material as described above has a periodic uneven surface on the side opposite to the photoelectric conversion substrate. In this case, since the X-ray detector detects the non-uniformity corresponding to the unevenness as an image, the quality of the image is deteriorated. Therefore, in the embodiment of the present invention, the above problems are improved, and a radiation detection panel and a method for manufacturing a radiation detection panel capable of improving the quality of the detected image can be obtained. Next, the means and methods for improving the above problems will be described.

[0014] Figure 1 FIG. is a cross-sectional view showing an X-ray detector 1 according to an embodiment. The X-ray detector 1 is an X-ray image detector and is an X-ray planar detector using an X-ray detection panel as a radiation detection panel. As Figure 1 shown, the X-ray detector 1 includes an X-ray detection module 10, a support substrate 12, a circuit substrate 11, spacers 9a, 9b, 9c, 9d, a housing 51, an FPC (flexible printed circuit) 2e1, an incident window 52, etc. The X-ray detection module 10 includes an X-ray detection panel PNL. The X-ray detection panel PNL is located between the support substrate 12 and the incident window 52. The X-ray detection panel PNL includes a moisture-proof cover 7 facing the incident window 52.

[0015] The incident window 52 is installed in the opening of the housing 51. The incident window 52 allows X-rays to pass through. Thus, the X-rays pass through the incident window 52 and enter the X-ray detection module 10. The incident window 52 is formed in a plate shape and has the function of protecting the interior of the housing 51. The incident window 52 is preferably formed thin from a material having a low X-ray absorption rate. Therefore, X-ray scattering generated in the incident window 52 and attenuation of the X-ray amount can be reduced. Then, a thin and light X-ray detector 1 can be realized. In the present embodiment, the incident window 52 is formed of carbon fiber reinforced plastic (CFRP). The X-ray detection module 10, the support substrate 12, the circuit board 11, the FPC 2e1, etc. are housed inside the space surrounded by the housing 51 and the incident window 52.

[0016] The X-ray detection module 10 is constituted by laminating thin members, and thus is light and has low mechanical strength. Therefore, the X-ray detection panel PNL (X-ray detection module 10) is fixed to one flat surface of the support substrate 12 via an adhesive sheet. The support substrate 12 is formed in a plate shape of, for example, aluminum alloy and has the strength required to stably hold the X-ray detection panel PNL. Therefore, damage to the X-ray detection panel PNL can be suppressed when vibration or impact is applied to the X-ray detector 1 from the outside.

[0017] The circuit board 11 is fixed to the other surface of the support substrate 12 via spacers 9a, 9b. The circuit board 11 is located at a position spaced apart from the X-ray detection panel PNL (the photoelectric conversion substrate 2 described later). By using the spacers 9a, 9b, an electrical insulation distance from the support substrate 12 mainly made of metal to the circuit board 11 can be maintained. The circuit board 11 is fixed to the inner surface of the housing 51 via spacers 9c, 9d. By using the spacers 9c, 9d, an electrical insulation distance from the housing 51 mainly made of metal to the circuit board 11 can be maintained. The housing 51 supports the support substrate 12 etc. via the circuit board 11 and the spacers 9a, 9b, 9c, 9d.

[0018] A connector corresponding to the FPC 2e1 is installed on the circuit board 11, and the FPC 2e1 is electrically connected to the circuit board 11 via the connector. The connection between the FPC 2e1 and the X-ray detection panel PNL uses a thermocompression bonding method using an ACF (anisotropic conductive film). By this method, electrical connection between a plurality of fine pads of the X-ray detection panel PNL and a plurality of fine pads of the FPC 2e1 is ensured. In addition, the pads of the X-ray detection panel PNL will be described later.

[0019] As described above, the circuit board 11 is electrically connected to the X-ray detection panel PNL (photoelectric conversion substrate 2) via the above-mentioned connector, FPC2e1, etc. The circuit board 11 electrically drives the X-ray detection panel PNL (photoelectric conversion substrate 2) and electrically processes the output signal from the X-ray detection panel PNL (photoelectric conversion substrate 2).

[0020] Figure 2 FIG. 4 is a perspective view showing the support substrate 12, the X-ray detection panel PNL, the circuit board 11, and a plurality of FPCs 2e1 and 2e2 of the X-ray detector 1 according to the above-described embodiment, and also shows the image transmission unit 4. In addition, Figure 2 not all components of the X-ray detector 1 are shown. Illustrations of some components of the X-ray detector 1, such as the reflection layer described later, are omitted in Figure 2 FIG. 4.

[0021] As Figure 2 shown, the X-ray detection panel PNL includes a photoelectric conversion substrate 2, a scintillator layer 5, etc. The photoelectric conversion substrate 2 has a substrate 2a, a photoelectric conversion section 2b, a plurality of control lines (or gate lines) 2c1, a plurality of data lines (or signal lines) 2c2, etc. In addition, the number, arrangement, etc. of the photoelectric conversion section 2b, the control lines 2c1, and the data lines 2c2 are not limited to Figure 2 the examples shown. The plurality of control lines 2c1 extend in the row direction X and are arranged at a predetermined interval in the column direction Y. The plurality of data lines 2c2 extend in the column direction Y, cross the plurality of control lines 2c1, and are arranged at a predetermined interval in the row direction X. Here, the direction orthogonal to the row direction X and the column direction Y is defined as the orthogonal direction Z.

[0022] A plurality of photoelectric conversion sections 2b are provided on the scintillator layer 5 side of the substrate 2a. The photoelectric conversion section 2b is provided in a quadrilateral region defined by the control lines 2c1 and the data lines 2c2. One photoelectric conversion section 2b corresponds to one pixel in the X-ray image. The plurality of photoelectric conversion sections 2b are arranged in a matrix. As described above, the photoelectric conversion substrate 2 is an array substrate.

[0023] Each photoelectric conversion section 2b has a photoelectric conversion element 2b1 and a TFT (thin film transistor) 2b2 as a switching element. The TFT 2b2 is connected to a corresponding one of the control lines 2c1 and a corresponding one of the data lines 2c2. The photoelectric conversion element 2b1 is electrically connected to the TFT 2b2.

[0024] The control line 2c1 is electrically connected to the circuit board 11 via the FPC 2e1. The circuit board 11 supplies the control signal S1 to the plurality of control lines 2c1 via the FPC 2e1. The data line 2c2 is electrically connected to the circuit board 11 via the FPC 2e2. The image data signal S2 (charge stored in the photoelectric conversion unit 2b) converted by the photoelectric conversion element 2b1 is transmitted to the circuit board 11 via the TFT 2b2, the data line 2c2, and the FPC 2e2.

[0025] The X-ray detector 1 further includes an image transmission unit 4. The image transmission unit 4 is connected to the circuit board 11 via the wiring 4a. Additionally, the image transmission unit 4 may be assembled to the circuit board 11. The image transmission unit 4 generates an X-ray image based on the signal of the image data converted into a digital signal by a plurality of analog-to-digital converters (not shown). The data of the generated X-ray image is output from the image transmission unit 4 to an external device.

[0026] Figure 3 is an enlarged cross-sectional view showing a part of the X-ray detection module 10 of the X-ray detector 1 according to the above-described embodiment. As Figure 3 shown, the photoelectric conversion substrate 2 has a substrate 2a, a plurality of photoelectric conversion units 2b, and insulating layers 21, 22, 23, 24, 25. The plurality of photoelectric conversion units 2b are located in the detection region DA. Each photoelectric conversion unit 2b includes a photoelectric conversion element 2b1 and a TFT 2b2, and converts the incident fluorescence into an electrical signal (in one example, an image data signal). The detection region DA is a region where fluorescence can reach the photoelectric conversion unit 2b when X-rays are incident on the scintillator layer 5 and emit fluorescence.

[0027] The TFT 2b2 has a gate electrode GE, a semiconductor layer SC, a source electrode SE, and a drain electrode DE. The photoelectric conversion element 2b1 is formed of, for example, a photodiode. Additionally, the photoelectric conversion element 2b1 may be formed of a CCD or the like as long as it is configured to convert light into charge.

[0028] The substrate 2a has a plate shape and is formed of an insulating material. Examples of the insulating material include glass such as non-alkali glass. The planar shape of the substrate 2a is, for example, a quadrilateral. The thickness of the substrate 2a is, for example, 0.7 mm. The insulating layer 21 is provided on the substrate 2a.

[0029] The gate electrode GE is formed on the insulating layer 21. The gate electrode GE is electrically connected to the above-described control line 2c1. The insulating layer 22 is provided on the insulating layer 21 and the gate electrode GE. The semiconductor layer SC is provided on the insulating layer 22 and faces the gate electrode GE. The semiconductor layer SC is formed of a semiconductor material such as amorphous silicon as an amorphous semiconductor, polycrystalline silicon as a polycrystalline semiconductor, or indium gallium zinc oxide (IGZO) as an oxide semiconductor.

[0030] The source electrode SE and the drain electrode DE are provided on the insulating layer 22 and the semiconductor layer SC. The gate electrode GE, the source electrode SE, the drain electrode DE, the above-mentioned control line 2c1, and the above-mentioned data line 2c2 are formed of a low-resistance metal such as aluminum or chromium. The source electrode SE is electrically connected to the source region of the semiconductor layer SC. In addition, the source electrode SE is electrically connected to the above-mentioned data line 2c2. The drain electrode DE is electrically connected to the drain region of the semiconductor layer SC.

[0031] An insulating layer 23 is provided on the insulating layer 22, the semiconductor layer SC, the source electrode SE, and the drain electrode DE. The photoelectric conversion element 2b1 is electrically connected to the drain electrode DE. An insulating layer 24 is provided on the insulating layer 23 and the photoelectric conversion element 2b1. The bias line BL is provided on the insulating layer 24 and is connected to the photoelectric conversion element 2b1 through a contact hole formed in the insulating layer 24. An insulating layer 25 is provided on the insulating layer 24 and the bias line BL. The insulating layers 21, 22, 23, 24, and 25 are formed of insulating materials such as inorganic insulating materials and organic insulating materials. Examples of the inorganic insulating material include oxide insulating materials, nitride insulating materials, and oxynitride insulating materials. Examples of the organic insulating material include resins.

[0032] The scintillator layer 5 is provided on the plurality of photoelectric conversion units 2b. The scintillator layer 5 is at least located in the detection region DA and covers the upper part of the plurality of photoelectric conversion units 2b. The scintillator layer 5 converts the incident radiation (in one example, X-rays) into fluorescence. In addition, the photoelectric conversion element 2b1 converts the fluorescence incident from the scintillator layer 5 into charges. The converted charges are stored in the photoelectric conversion element 2b1. The TFT 2b2 can switch the charge storage in and the discharge from the photoelectric conversion element 2b1. In addition, when the self-capacitance of the photoelectric conversion element 2b1 is insufficient, the photoelectric conversion substrate 2 may further include a capacitor (storage capacitor), and the charges converted by the photoelectric conversion element 2b1 can be stored in the capacitor.

[0033] The scintillator layer 5 is provided on the photoelectric conversion substrate 2 and has one surface 5a facing the photoelectric conversion substrate and another surface 5b located on the opposite side of the one surface. The scintillator layer 5 is formed of, for example, thallium-activated cesium iodide (CsI:Tl). If the scintillator layer 5 is formed by a vacuum evaporation method, a scintillator layer 5 formed of an aggregate of a plurality of columnar crystals is obtained. Each of the plurality of columnar crystals has a tapered upper end portion 5b1 with a gradually decreasing diameter. The other surface 5b is composed of the surfaces of the plurality of upper end portions 5b1. The thickness of the scintillator layer 5 is, for example, 600 μm. On the outermost surface of the scintillator layer 5, the thickness of the columnar crystals of the scintillator layer 5 is 3 to 10 μm.

[0034] The material forming the scintillator layer 5 is not limited to thallium-activated cesium iodide. The scintillator layer 5 can be formed of thallium-activated sodium iodide (NaI:Tl), sodium-activated cesium iodide (CsI:Na), europium-activated cesium bromide (CsBr:Eu), sodium iodide (NaI), gadolinium oxysulfide (Gd2O2S), etc.

[0035] The moisture-proof cover 7 is provided above the scintillator layer 5 and covers the scintillator layer 5. In addition, the scintillator layer 5 has hygroscopicity. The moisture-proof cover 7 is provided to suppress deterioration of the characteristics of the scintillator layer 5 due to moisture contained in the atmosphere. The moisture-proof cover 7 completely covers the exposed portion of the scintillator layer 5. The moisture-proof cover 7 is formed of a metal-containing sheet. As the above metal, an aluminum-containing metal, a copper-containing metal, a magnesium-containing metal, a tungsten-containing metal, stainless steel, kovar, etc. can be cited. When the moisture-proof cover 7 contains a metal, the moisture-proof cover 7 can prevent or significantly suppress the penetration of moisture.

[0036] The X-ray detection panel PNL further includes a reflective layer 6. The reflective layer 6 is provided on the other surface 5b of the scintillator layer. That is, it is provided on the X-ray incident side of the scintillator layer 5. The reflective layer 6 is located between the scintillator layer 5 and the moisture-proof cover 7. The reflective layer 6 is at least located in the detection area DA and covers the upper surface of the scintillator layer 5. The reflective layer 6 is provided to improve the utilization efficiency of fluorescence and achieve an improvement in sensitivity characteristics. That is, the reflective layer 6 reflects the fluorescence in the scintillator layer 5 that is directed to the side opposite to the side where the plurality of photoelectric conversion portions 2b are provided, to the plurality of photoelectric conversion portions 2b. The reflective layer 6 is composed of a plurality of mixtures 6a. The reflective layer 6 has a facing surface 63 facing the other surface 5b of the scintillator layer 5 and a concavo-convex surface 64 located on the opposite side of the facing surface 63.

[0037] Figure 4 is a schematic view showing Figure 3 an enlarged cross-sectional view of one of the plurality of mixtures 6 shown. As Figure 4 shown, each of the plurality of mixtures 6a is a particle formed of an adhesive (adhesive material) 61 and light-scattering particles 62. That is, the reflective layer 6 is formed of the adhesive 61 and the light-scattering particles 62. The adhesive 61 is, for example, a resin. The adhesive 61 bonds the light-scattering particles 62 to each other and bonds the light-scattering particles to the scintillator layer 5. The light-scattering particles 62 are, for example, titanium oxide (TiO2). In one example, the mixture 6a includes three light-scattering particles 62. In addition, the number of light-scattering particles 62 is not limited to three, and can be more than three or less than three. For example, the number of light-scattering particles 62 can be two or four. In one example, the light-scattering particles 62 are formed in a quadrilateral shape, but are not limited to a quadrilateral shape. Figure 4The mixture 6a shown in [figure] has a spherical shape. The shape of the mixture 6a is not limited to a sphere. For example, each mixture 6a may be recessed at the other surface 5b of the scintillator layer 5 or at the portion in contact with other mixtures 6a. The size of the mixture 6a is about 0.1 to 1 μm.

[0038] Reference Figures 5 to 7 Describe the reflective layer 6 in detail. Figure 5 is a top view showing a part of the reflective layer 6 of the X-ray detector 1 according to the above-described embodiment, and is a view observed from the moisture-proof cover 7 side. In Figure 5 the convex portions 64a of the reflective layer 6 to be described later are marked with diagonals rising to the right. In addition, the center of gravity G and the top TP of each convex portion are described. Figure 6 is along Figure 5 sectional view taken along line A-A of Figure 7 is along Figure 5 sectional view taken along line B-B of Figure 6 and Figure 7 are views showing the top TP of each convex portion 64a and magnifying the reflective layer 6 and the scintillator layer 5. In addition, in the orthogonal direction Z, Figure 6 the position of the imaginary plane S shown in Figure 7 is the same as the position of the imaginary plane S shown in

[0039] As Figure 5 shown, the uneven surface 64 includes the surfaces of a plurality of convex portions 64a and the surfaces of concave portions 64b. The plurality of convex portions 64a have adjacent convex portions 64a. For example, the first convex portion 64a1 is adjacent to the second convex portion 64a2, the third convex portion 64a3, the fourth convex portion 64a4, and the like. As described above, each of the plurality of convex portions 64a is adjacent to three or more convex portions 64a. In addition, each of the plurality of convex portions 64a may be adjacent to two or fewer convex portions. The plurality of convex portions 64a may be located on a straight line.

[0040] The direction from each of the plurality of convex portions 64a toward an adjacent convex portion 64a is random. Specifically, the direction from the center of gravity G of each of the plurality of convex portions 64a toward the center of gravity G of an adjacent convex portion 64a is random. For example, the direction d1 from the center of gravity G1 of the first convex portion 64a1 toward the center of gravity G2 of the second convex portion 64a2 is different from the direction d2 from the center of gravity G2 of the second convex portion 64a2 toward the center of gravity G3 of the third convex portion 64a3. In addition, when each of the plurality of convex portions 64a is adjacent to a plurality of convex portions 64a, the direction from each of the plurality of convex portions 64a toward each adjacent convex portion 64a is random. For example, the direction d1 from the center of gravity G1 of the first convex portion 64a1 toward the center of gravity G2 of the second convex portion 64a2 is different from the direction d2 from the center of gravity G1 of the first convex portion 64a1 toward the center of gravity G3 of the third convex portion 64a3.

[0041] As Figure 6 and Figure 7 shown, the opposite face 63 includes a plurality of contact surfaces 63a that contact and are fixed to another face 5b, and non-contact surfaces 63b that are disposed with a gap and oppose another face 5b. That is, in the opposite face 63 of the reflective layer 6 facing the other face 5b of the scintillator layer 5, there are provided contact surfaces 63a that contact and are fixed to another face 5b, and non-contact surfaces 63b that are located at positions away from another face 5b. The details of the opposite face 63 will be described later in the description of Figure 8 .

[0042] The uneven face 64 includes the surfaces of a plurality of convex portions 64a that protrude in a direction away from the scintillator layer 5 and the surfaces of concave portions 64b that are more recessed than the plurality of convex portions 64a. In one example, the direction in which the convex portions 64a protrude coincides with the orthogonal direction Z. Each of the plurality of convex portions 64a is formed of a plurality of mixtures 6a. The convex portions 64a are located on the upper side (the side opposite to the scintillator layer 5) in the orthogonal direction Z of a hypothetical plane S as a reference. The concave portions 64b are located on the lower side (the scintillator layer 5 side) in the orthogonal direction Z of the hypothetical plane S.

[0043] In addition, the hypothetical plane S is a plane orthogonal to the direction in which the plurality of convex portions 64a protrude (in one example, the orthogonal direction Z). In the orthogonal direction Z, the hypothetical plane S can be set at any position between the maximum position where the height of the uneven face 64 becomes maximum and the minimum position where the height of the uneven face 64 becomes minimum. For example, the hypothetical plane S can be set at an intermediate position between the maximum position and the minimum position. The interval from each of the plurality of convex portions 64a to an adjacent convex portion 64a is random. That is, the interval from each of the plurality of convex portions 64a to an adjacent convex portion 64a is not uniform.

[0044] Specifically, the interval from the center of gravity G of each of the plurality of convex portions 64a to the center of gravity G of an adjacent convex portion 64a is random. For example, the interval SG1 from the center of gravity G1 of the first convex portion 64a1 to the center of gravity G2 of the second convex portion 64a2 is different from the interval SG2 from the center of gravity G2 of the second convex portion 64a2 to the center of gravity G3 of the third convex portion 64a3 (refer to Figure 5 ). In addition, in the present embodiment, the interval from the top TP of each of the plurality of convex portions 64a to the top TP of an adjacent convex portion 64a is also random. For example, the interval ST1 from the top TP1 of the first convex portion 64a1 to the top TP2 of the second convex portion 64a2 is different from the interval ST2 from the top TP2 of the second convex portion 64a2 to the third convex portion 64a3 (refer to Figure 6 and Figure 7 ).

[0045] The heights of the plurality of convex portions 64a are random. More specifically, among the plurality of convex portions 64a, the heights from a hypothetical plane S (hereinafter simply referred to as "the same hypothetical plane S") having the same position in the orthogonal direction Z to the respective tops TP are random. In other words, among the plurality of convex portions 64a, the heights from the same hypothetical plane S to the respective tops are not uniform. For example, the height T1 from the hypothetical plane S to the top TP1 is different from the height T2 from the hypothetical plane S to the top TP2 and the height T3 from the hypothetical plane S to the top TP3.

[0046] The plurality of convex portions 64a have random shapes in a first cross-section parallel to the direction in which the plurality of convex portions 64a protrude. That is, in the first cross-section, the shapes of the plurality of convex portions 64a are not uniform. For example, in Figure 6 the shape of the first convex portion 64a1 is different from the shape of the second convex portion 64a2. In addition, in Figure 7 the shape of the second convex portion 64a2 is different from the shape of the third convex portion 64a3. Additionally, Figure 6 and Figure 7 the cross-sections shown are cross-sections including the top TP, but the first cross-section is not limited to including the top TP. That is, even in a cross-section parallel to the direction in which the plurality of convex portions 64a protrude and not including the top TP, the plurality of convex portions 64a have random shapes.

[0047] The concave surface CS that is the surface of the concave portion 64b includes a first concave surface CS1 located between the first convex portion 64a1 and the second convex portion 64a2, and a second concave surface CS2 located between the second convex portion 64a2 and the third convex portion 64a3. The depth of the concave surface CS is random. More specifically, in the first cross-section, the depth from the same hypothetical plane S to the concave surface CS is random. That is, in the first cross-section, the depth from the same hypothetical plane S to the concave surface CS is not uniform. For example, in the first cross-section, the depth D1 from the same hypothetical plane S to the bottom B1 of the first concave surface CS1 is different from the depth D2 from the same hypothetical plane S to the bottom B2 of the second concave surface CS2.

[0048] As Figure 5 shown, when viewed from above in the direction of the moisture-proof cover 7, the plurality of convex portions 64a are formed in random shapes. In other words, when a cross-section orthogonal to the direction in which the plurality of convex portions 64a protrude is defined as a second cross-section, the shapes of the plurality of convex portions 64a are random in the second cross-section (hereinafter simply referred to as "the same second cross-section") having the same position in the orthogonal direction Z. Additionally, the second cross-section is a cross-section between the position where the height of the concavo-convex surface 64 becomes maximum and the position where the height of the concavo-convex surface 64 becomes minimum in the orthogonal direction Z.

[0049] That is, in the same second cross-section, the shapes of the plurality of convex portions 64a are non-uniform. For example, in the same second cross-section, the shape of the first convex portion 64a1 is different from the shapes of the second convex portion 64a2 and the third convex portion 64a3. In short, the shapes of the plurality of convex portions 64a are random in the first cross-section (refer to Figure 6 and Figure 7 ). The plurality of convex portions 64a includes a frame-shaped fourth convex portion 64a4. A concave portion 64b4 is located inside the fourth convex portion 64a. The concave portion 64b4 is independent of the other concave portions 64b. As described above, the uneven surface 64 may include the surfaces of the plurality of concave portions 64b.

[0050] When viewed from above in the direction of the moisture-proof cover 7, the plurality of convex portions 64a have random areas. In other words, in the same second cross-section, the areas of the plurality of convex portions 64a are random. That is, in the same second cross-section, the areas of the plurality of convex portions 64a are non-uniform. For example, in the same second cross-section, the area of the first convex portion 64a1 is different from the areas of the second convex portion 64a2, the third convex portion 64a3, and the fourth convex portion 64a4. Since the heights of the plurality of convex portions 64a from the top are random (refer to Figure 6 and Figure 7 ), the areas of the plurality of convex portions 64a in the second cross-section are random, and thus the sizes of the plurality of convex portions 64a are random.

[0051] Figure 8 is Figure 6 a top view of arrow C in Figure 8 , and is a view showing a part of the opposing surface 63 in the reflective layer 6. In Figure 8 , a downward-slanting line to the right is marked on the contact surface 63a. As Figure 8 shows, the sizes of the plurality of contact surfaces 63a are random. That is, the sizes of the plurality of contact surfaces 63a are non-uniform. For example, the size of the first contact surface 63a1 is different from the size of the second contact surface 63a2. When the mixture 6a has a spherical shape without depressions and is in point contact with another surface 5b, the opposing surface 63 includes the point where the mixture 6a contacts the another surface 5b.

[0052] The plurality of contact surfaces 63a includes contact surfaces 63a formed by the surface of one mixture 6a such as the first contact surface 63a1 and the second contact surface 63a2, and contact surfaces 63a formed by the surfaces of a plurality of mixtures 6a such as the third contact surface 63a3 and the fourth contact surface 63a4. The shapes of the contact surfaces 63a formed by the surfaces of a plurality of mixtures 6a are random. For example, the shape of the third contact surface 63a3 is different from the shape of the fourth contact surface 63a4. The fourth contact surface 63a4 is formed in a frame shape, and the non-contact surface 63b4 is located inside the fourth contact surface 63a4. The non-contact surface 63b4 is independent of the other non-contact surfaces 63b. As described above, the opposing surface 63 may include a plurality of non-contact surfaces 63b.

[0053] Figure 9 It is a top view of the X-ray detection module 10 of the X-ray detector 1 according to the above-described embodiment. Figure 9 In [the figure], a diagonal line rising to the right is marked on the scintillator layer 5, and a diagonal line falling to the right is marked on the sealing portion 8. Figure 10 It is along Figure 9 the cross-sectional view of the X-ray detection module 10 taken along the line D-D. As Figure 9 and Figure 10 shown, the photoelectric conversion substrate 2 has a detection region DA and a non-detection region outside the detection region DA. The detection region DA is a quadrilateral region. The non-detection region of the photoelectric conversion substrate 2 has a frame-shaped first non-detection region NDA1 surrounding the detection region DA and a second non-detection region NDA2 outside the first non-detection region NDA1. In the present embodiment, the second non-detection region NDA2 has a frame shape.

[0054] The scintillator layer 5 is at least located in the detection region DA. The scintillator layer 5 has one surface 5a, another surface 5b, and a side surface 5c. The side surface 5c is located in the first non-detection region NDA1. The side surface 5c is a tapered surface. The photoelectric conversion substrate 2 also has a plurality of pads 2d1 and a plurality of pads 2d2. The pads 2d1 and the pads 2d2 are located in the second non-detection region NDA2. In the present embodiment, the plurality of pads 2d1 are arranged along the left side of the substrate 2a, and the plurality of pads 2d2 are arranged along the lower side of the substrate 2a. For example, the pads 2d1 and 2d2 are provided on the insulating layer 23 and are not covered by the insulating layers 24 and 25.

[0055] The X-ray detection module 10 further includes a sealing portion 8. The sealing portion 8 is located in the first non-detection region NDA1 and surrounds the scintillator layer 5. The sealing portion 8 has a frame shape and continuously extends around the scintillator layer 5. The sealing portion 8 is adhered to the photoelectric conversion substrate 2 (for example, the insulating layer 25). If the shape of the outer surface 8a of the sealing portion 8 is a curved surface protruding outward, it is easy for the vicinity of the edge of the moisture-proof cover 7 to imitate the outer surface 8a of the sealing portion 8.

[0056] The reflection layer 6 and the moisture-proof cover 7 are located in the detection region DA and the first non-detection region NDA1. In Figure 9 the top view shown, the moisture-proof cover 7 completely covers the scintillator layer 5. The moisture-proof cover 7 covers at least a part of the sealing portion 8. There are voids in the scintillator layer 5 that are approximately 10 to 40% of its volume. Therefore, if the voids contain gas, when the X-ray detector 1 is transported by an aircraft or the like, or when the X-ray detector 1 is used at a high altitude, the gas may expand and damage the moisture-proof cover 7. If the moisture-proof cover 7 and the sealing portion 8 are joined in an environment decompressed compared to the atmospheric pressure, damage to the moisture-proof cover 7 can be suppressed even when the X-ray detector 1 is transported by an aircraft or the like. Therefore, the pressure in the space surrounded by the photoelectric conversion substrate 2, the sealing portion 8, and the moisture-proof cover 7 is preferably lower than the atmospheric pressure. The X-ray detector 1 of the present embodiment is configured as described above.

[0057] Next, a method for manufacturing the X-ray detection panel PNL according to the above embodiment will be described. Figure 11 It is a cross-sectional view showing an example when forming the reflection layer 6 in the X-ray detection panel PNL according to the above embodiment. As Figure 11 shown, when starting to manufacture the X-ray detection panel PNL, first, the photoelectric conversion substrate 2 is prepared, and the scintillator layer 5 is formed on the photoelectric conversion substrate 2. Next, a first mixed material 6b formed of an adhesive 61, light-scattering particles 62, and a solvent for dissolving the adhesive 61 is prepared. In one example, the first mixed material 6b is formed by mixing the adhesive 61, the light-scattering particles 62, and the solvent.

[0058] The solvent is, for example, an organic solvent such as cyclohexanone and is used to dissolve the adhesive 61. The solvent imparts fluidity to the first mixed material 6b and improves its coating (dispersion) property. For example, when the first mixed material 6b is formed only of the adhesive 61 and the light-scattering particles 62, the coating (dispersion) property is poor due to too high viscosity. The viscosity of the first mixed material 6b is, for example, about 2000 MPa·s. In addition, the first mixed material 6b is accommodated in the container 41 of the sprayer 40.

[0059] Thereafter, by processing the first mixed material 6b into a plurality of particles, a plurality of second mixed materials 6c are formed. Each of the plurality of second mixed materials 6c is a particle formed of the adhesive 61, the light-scattering particles 62, and the solvent, and the plurality of second mixed materials 6c are scattered on the other surface 5b of the scintillator layer 5. Specifically, the first mixed material 6b is converted into particulate (mist-like) second mixed materials 6c by the nozzle 42 of the sprayer 40, and the plurality of second mixed materials 6c are scattered from the spray port 43 of the sprayer 40 onto the scintillator layer 5. In one example, the direction in which the plurality of second mixed materials 6c are scattered is the same as the gravity direction GD. In addition, the direction in which the plurality of second mixed materials 6c are scattered is not limited to being the same as the gravity direction GD, and may be, for example, a direction orthogonal to the gravity direction GD.

[0060] At this time, it is preferable to perform the scattering in a state where the distance L from the scintillator layer 5 to the spray port 43 is relatively long. For example, by setting the distance L to about 50 cm or so, it becomes easy to form a plurality of convex portions 64a provided at random intervals in the reflection layer 6. In addition, the method of forming a plurality of second mixed materials 6c from the first mixed material 6b and scattering the plurality of second mixed materials 6c is not limited to the method using the sprayer 40.

[0061] Next, the plurality of second mixed materials 6c scattered on the other surface are dried to form the reflection layer 6. More specifically, since the solvent in the plurality of second mixed materials 6c volatilizes, the plurality of second mixed materials 6c become a plurality of mixtures 6a, thereby forming the reflection layer 6. Thus, the manufacturing of the X-ray detection panel PNL is completed. Drying can be performed, for example, in a dryer through which dry air flows. The drying temperature can be, for example, room temperature. The drying time can be appropriately changed according to the ratio of the solvent, the thickness of the layer formed by the plurality of second mixed materials 6c that have been scattered, the drying conditions, and the like.

[0062] When scattering the plurality of second mixed materials 6c as described above, the solvent also volatilizes between the spray port 43 and the other surface 5b of the scintillator layer 5. Therefore, compared with the case where the first mixed material 6b is coated on the scintillator layer 5 by a dispenser, when the second mixed material 6c is dried, the tensile stress applied to the scintillator layer can be suppressed. In addition, compared with the case where the first mixed material 6b is coated on the scintillator layer 5 by a dispenser, the drying time can be set to 1 / 10 or less. The drying time in the present embodiment is, for example, about 30 minutes or so.

[0063] The effects of the present embodiment will be described. According to the radiation detection panel and the manufacturing method of the radiation detection panel according to the present embodiment configured as described above, the radiation detection panel includes a reflection layer 64, and the reflection layer 64 has an uneven surface 64 including a surface having a plurality of convex portions 64a. The interval from each of the plurality of convex portions 64a to an adjacent convex portion 64a is random. In a radiation detector including the reflection layer 6, when acquiring an X-ray image, unevenness corresponding to the unevenness of the reflection layer 6 is detected, where the reflection layer 6 has an uneven surface including a surface having a plurality of convex portions positioned at periodic intervals. On the other hand, in a radiation detector including a reflection layer, when acquiring an X-ray image, unevenness corresponding to the unevenness is not detected, where the reflection layer has an uneven surface including a surface having a plurality of convex portions with random intervals from each convex portion to an adjacent convex portion. That is, a radiation detection panel capable of improving the quality of the detected image can be obtained.

[0064] The direction from each of the plurality of convex portions 64a toward an adjacent convex portion 64a is random. The sizes of the plurality of convex portions 64a are random. In the first cross-section and the second cross-section, the shapes of the plurality of convex portions 64a are random. In the first cross-section, the depth of the concave portion to the surface is random. Each of the plurality of convex portions 64a is formed of a plurality of mixtures 6a.

[0065] Thus, compared with a radiation detector having a reflection layer with a concavo-convex surface including periodicity, the reflection of the shape generated in the scintillator layer 5 can be complicated, and thus the amount of fluorescence transmitted through the reflection layer can be suppressed. That is, a radiation detection panel with high sensitivity can be obtained. In addition, the above-mentioned periodic concavo-convex surface is, for example, a concavo-convex surface including a surface of a plurality of convex portions positioned at periodic intervals, a concavo-convex surface including a surface of a plurality of convex portions positioned along a fixed direction, a concavo-convex surface including a surface of a plurality of convex portions formed with a fixed size, a concavo-convex surface including a surface of a plurality of convex portions formed with a fixed shape, and a concavo-convex surface including a concave portion with a fixed depth.

[0066] The reflection layer 6 has a facing surface 63 facing the other surface 5b of the scintillator layer 5. The facing surface 63 includes a plurality of contact surfaces 63a that are in contact with and fixed to the other surface 5b, and non-contact surfaces 63b that are provided with a gap and face the other surface. The reflection layer 6 is composed of a plurality of mixtures 6a, and each of the plurality of mixtures 6a is a particle formed of an adhesive and light-scattering particles. By compressing (drying) the mixed material (in one example, a plurality of second mixed materials 6c) of the reflection layer 6 attached to the other surface 5b, the larger the area of contact between the mixed material and the scintillator layer 5, the greater the tensile stress applied to the scintillator layer 5. By reducing the above area, the tensile stress applied to the scintillator layer 5 can be reduced, and thus the peeling of the scintillator layer 5 corresponding to the compression of the mixed material and the deformation of the X-ray detection panel PNL can be suppressed.

[0067] Although the embodiments of the present invention have been described, the above embodiments are presented as examples and are not intended to limit the scope of the invention. The above new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. The above embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims of the patent and its equivalents.

Claims

1. A radiation detection panel, characterized in that, Comprising: A photoelectric conversion substrate having a plurality of photoelectric conversion portions that convert fluorescence into an electrical signal; A scintillator layer disposed on the photoelectric conversion substrate, having one surface facing the photoelectric conversion substrate and another surface located on the opposite side of the one surface, and converting radiation into fluorescence; and A reflective layer disposed on the another surface, formed of an adhesive and light-scattering particles, and reflecting the fluorescence generated by the scintillator layer toward the plurality of photoelectric conversion portions, The reflective layer includes a facing surface facing the another surface, and a concavo-convex surface located on the opposite side of the facing surface, The concavo-convex surface includes a surface of a plurality of convex portions protruding in a direction away from the scintillator layer, and a surface of a concave portion that is more recessed than the plurality of convex portions, Each of the plurality of convex portions includes a convex portion adjacent to each of the plurality of convex portions, The interval from each of the plurality of convex portions to the adjacent convex portion is random.

2. The radiation detection panel according to claim 1, wherein The direction from the center of gravity of each of the plurality of convex portions to the center of gravity of the adjacent convex portion is random.

3. The radiation detection panel according to claim 1, wherein The reflective layer is composed of a plurality of mixtures, Each of the plurality of mixtures is a particle formed of an adhesive and light-scattering particles.

4. The radiation detection panel according to claim 3, wherein Each of the plurality of convex portions is formed of the plurality of mixtures.

5. The radiation detection panel according to claim 1, wherein The facing surface includes a plurality of contact surfaces in contact with and fixed to the another surface, and non-contact surfaces provided with a gap and opposite to the another surface.

6. A method for manufacturing a radiation detection panel, characterized in that Prepare a photoelectric conversion substrate having a plurality of photoelectric conversion portions that convert incident fluorescence into an electrical signal, Form a scintillator layer on the photoelectric conversion substrate, the scintillator layer having one surface facing the photoelectric conversion substrate and another surface located on the opposite side of the one surface, and converting radiation into fluorescence, Prepare a first mixed material formed of an adhesive, light-scattering particles, and a solvent for dissolving the adhesive, By processing the first mixed material into a plurality of particles, thereby forming a plurality of second mixed materials, each of the plurality of second mixed materials being a particle formed of the adhesive, the light-scattering particles, and the solvent, Disperse the plurality of second mixed materials on the another surface, By drying the plurality of second mixed materials dispersed on the another surface, thereby forming a reflective layer that reflects the fluorescence generated by the scintillator layer toward the plurality of photoelectric conversion portions.

Images