radiation detector

Abstract

The object of the present invention is to provide a radiation detector that can efficiently cause fluorescence incident on a reflective layer to enter a scintillator. [Solution] A radiation detector according to an embodiment includes an array substrate having a plurality of photoelectric conversion units, a scintillator disposed on the plurality of photoelectric conversion units and converting incident radiation into fluorescence, and a reflective layer disposed on the side of the scintillator opposite the plurality of photoelectric conversion units, the reflective layer including a base containing resin and a plurality of elements disposed inside the base. The elements are translucent and include at least one of a material having a refractive index higher than the refractive index of the resin contained in the base and a metal.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a radiation detector. [Background technology]

[0002] An example of a radiation detector is an X-ray detector. An X-ray detector includes a scintillator that converts incident X-rays into fluorescence and multiple photoelectric conversion units that convert the incident fluorescence into electric charges. In this case, the scintillator is provided on the photoelectric conversion units, and the fluorescence converted from X-rays inside the scintillator propagates inside the scintillator and enters the photoelectric conversion units.

[0003] Here, the fluorescence generated inside the scintillator spreads in all directions, and therefore fluorescence may propagate inside the scintillator in the opposite direction from the photoelectric conversion unit side. If the amount of fluorescence propagating inside the scintillator in the opposite direction from the photoelectric conversion unit side increases, the amount of fluorescence reaching the photoelectric conversion unit decreases, which may result in a decrease in sensitivity.

[0004] For this reason, a reflective layer that reflects fluorescence is provided on the side of the scintillator opposite the photoelectric conversion section. Typically, the reflective layer contains titanium dioxide particles and a resin. When fluorescence enters the reflective layer from the scintillator, the fluorescence is scattered by the titanium dioxide particles, and some of the scattered fluorescence enters the scintillator. This increases the amount of fluorescence that reaches the photoelectric conversion section, thereby improving sensitivity. However, when the fluorescence is scattered by the titanium dioxide particles, the fluorescence spreads over a relatively wide range, making it difficult to further increase the amount of fluorescence incident on the scintillator.

[0005] Therefore, there has been a demand for the development of a radiation detector that can efficiently cause the fluorescence incident on the reflective layer to enter the scintillator. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-283483 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a radiation detector that can efficiently cause fluorescence incident on a reflective layer to enter a scintillator. [Means for solving the problem]

[0008] A radiation detector according to an embodiment includes an array substrate having a plurality of photoelectric conversion units, a scintillator provided on the plurality of photoelectric conversion units and converting incident radiation into fluorescence, and a reflective layer provided on the side of the scintillator opposite the plurality of photoelectric conversion units, the reflective layer including a base including a resin and a plurality of elements provided inside the base, the elements having translucency and including at least one of a material having a refractive index higher than the refractive index of the resin contained in the base and a metal. [Effects of the Invention]

[0009] According to an embodiment of the present invention, it is possible to provide a radiation detector that can efficiently cause fluorescence incident on a reflective layer to enter a scintillator. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic perspective view illustrating an X-ray detector according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view illustrating an X-ray detector. [Figure 3] FIG. 1 is a block diagram of an X-ray detector. [Figure 4] FIG. 10 is a schematic cross-sectional view illustrating a reflective layer according to a comparative example. [Figure 5] 3A and 3B are schematic cross-sectional views illustrating a reflective layer according to the present embodiment. [Figure 6]5A and 5B are schematic cross-sectional views for illustrating the effects of elements. [Figure 7] 10A and 10B are schematic cross-sectional views illustrating a reflective layer according to another embodiment. [Figure 8] 10A and 10B are schematic cross-sectional views illustrating a reflective layer according to another embodiment. [Figure 9] 10A and 10B are schematic cross-sectional views illustrating a reflective layer according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be illustrated with reference to the drawings. In the drawings, like components are designated by like reference numerals and detailed descriptions thereof will be omitted where appropriate.

[0012] Furthermore, the radiation detector according to the embodiment of the present invention can be applied to various types of radiation, such as gamma rays, in addition to X-rays. Here, as an example, a case of X-rays, which are a representative type of radiation, will be described. Therefore, by replacing "X-rays" in the following embodiments with "other radiation," the radiation detector can also be applied to other types of radiation.

[0013] The radiation detector can also be used in general medical applications, for example. However, the applications of the radiation detector are not limited to general medical applications. For example, the radiation detector can also be used in non-destructive testing.

[0014] FIG. 1 is a schematic perspective view illustrating an X-ray detector 1 according to the present embodiment. In order to avoid complication, the protective layer 2f, the moisture-proof part 5, and the adhesive part 6 are omitted from FIG. FIG. 2 is a schematic cross-sectional view illustrating the X-ray detector 1. As shown in FIG. To avoid complication, the circuit section 4 is omitted from Fig. 2. Fig. 3 is a block diagram of the X-ray detector 1.

[0015] As shown in FIGS. 1 and 2, the X-ray detector 1 includes, for example, an array substrate 2, a scintillator 3, a circuit section 4, a moisture-proof section 5, an adhesive section 6, and a reflective layer 7.

[0016] The array substrate 2 may be provided with a substrate 2a, a photoelectric conversion section 2b, a control line (or gate line) 2c1, a data line (or signal line) 2c2, a wiring pad 2d1, a wiring pad 2d2, and a protective layer 2f. The numbers of photoelectric conversion units 2b, control lines 2c1, and data lines 2c2 are not limited to those shown in the example.

[0017] The substrate 2a has a plate shape and is made of glass such as alkali-free glass, etc. The planar shape of the substrate 2a is, for example, a rectangle.

[0018] A plurality of photoelectric conversion units 2b are provided on one surface of the substrate 2a. The photoelectric conversion units 2b are, for example, rectangular and are provided in an area defined by a control line 2c1 and a data line 2c2. The plurality of photoelectric conversion units 2b can be arranged in a matrix. Note that one photoelectric conversion unit 2b corresponds to, for example, one pixel of an X-ray image.

[0019] Each of the photoelectric conversion units 2b includes, for example, a photoelectric conversion element 2b1 and a thin film transistor (TFT) 2b2, which is a switching element. A storage capacitor (not shown) may also be provided to store the signal charge converted by the photoelectric conversion element 2b1. The storage capacitor may have, for example, a rectangular plate shape and be provided below each thin film transistor 2b2. However, depending on the capacitance of the photoelectric conversion element 2b1, the photoelectric conversion element 2b1 may also function as the storage capacitor.

[0020] The photoelectric conversion element 2b1 is, for example, a photodiode.

[0021] The thin-film transistor 2b2 switches between storing and discharging charges in the storage capacitor. The thin-film transistor 2b2 has, for example, a gate electrode 2b2a, a drain electrode 2b2b, and a source electrode 2b2c. The gate electrode 2b2a of the thin-film transistor 2b2 is electrically connected to, for example, a corresponding control line 2c1. The drain electrode 2b2b of the thin-film transistor 2b2 is electrically connected to, for example, a corresponding data line 2c2. The source electrode 2b2c of the thin-film transistor 2b2 is electrically connected to, for example, a corresponding photoelectric conversion element 2b1 and a storage capacitor. The anode side of the photoelectric conversion element 2b1 and the storage capacitor can be electrically connected to ground. The anode side of the photoelectric conversion element 2b1 and the storage capacitor can also be electrically connected to a bias line (not shown).

[0022] A plurality of control lines 2c1 can be provided parallel to each other at a predetermined interval. The control lines 2c1 extend, for example, in the row direction. Each control line 2c1 is electrically connected to one of a plurality of wiring pads 2d1 provided near the periphery of the substrate 2a. One of a plurality of wirings provided on the flexible printed circuit board 2e1 is electrically connected to one wiring pad 2d1. The other ends of the plurality of wirings provided on the flexible printed circuit board 2e1 are electrically connected to a readout circuit 4a provided in the circuit unit 4.

[0023] A plurality of data lines 2c2 can be provided parallel to each other at a predetermined interval. The data lines 2c2 extend, for example, in a column direction perpendicular to the row direction. Each data line 2c2 is electrically connected to one of a plurality of wiring pads 2d2 provided near the periphery of the substrate 2a. One of a plurality of wires provided on the flexible printed circuit board 2e2 is electrically connected to one of the wiring pads 2d2. The other ends of the plurality of wires provided on the flexible printed circuit board 2e2 are electrically connected to a signal detection circuit 4b provided in the circuit unit 4.

[0024] The control line 2c1 and the data line 2c2 are formed using a low resistance metal such as aluminum or chromium.

[0025] The protective layer 2f covers, for example, the photoelectric conversion unit 2b, the control line 2c1, and the data line 2c2. The protective layer 2f is made of, for example, an insulating material such as an oxide or a nitride.

[0026] The scintillator 3 is provided on the plurality of photoelectric conversion units 2b and converts incident X-rays 100 into fluorescence, i.e., visible light. The scintillator 3 can be provided on the substrate 2a so as to cover the region where the plurality of photoelectric conversion units 2b are provided (effective pixel region A).

[0027] The scintillator 3 is formed using, for example, cesium iodide (CsI):thallium (Tl), sodium iodide (NaI):thallium (Tl), or cesium bromide (CsBr):europium (Eu). The scintillator 3 is formed using, for example, a vacuum deposition method. If the scintillator 3 is formed using the vacuum deposition method, a scintillator 3 including a plurality of columnar crystals is formed.

[0028] When forming the scintillator 3 using the vacuum deposition method, a mask with openings is used. In this case, the portion of the scintillator 3 formed at the position of the mask opening (the portion of the scintillator 3 formed on the effective pixel area A) has a substantially constant thickness. The portion of the scintillator 3 formed outside the position of the mask opening (the portion of the scintillator 3 formed outside the effective pixel area A) has a thickness that gradually decreases toward the outside.

[0029] The scintillator 3 can also be formed using, for example, terbium-activated gadolinium sulfate (Gd2O2S / Tb or GOS) etc. In this case, a matrix of grooves can be provided so that a square pillar-shaped scintillator 3 is provided for each of the multiple photoelectric conversion units 2b.

[0030] 1 and 2 is a scintillator that includes a plurality of columnar crystals and is formed using a vacuum deposition method. In the following, as an example, a case where the scintillator 3 includes a plurality of columnar crystals will be described.

[0031] 1, the circuit unit 4 is provided, for example, on the side of the array substrate 2 opposite to the side on which the scintillator 3 is provided. For example, the circuit unit 4 is electrically connected to the array substrate 2 via flexible printed circuit boards 2e1 and 2e2.

[0032] As shown in FIG. 3, the circuit section 4 includes, for example, a read circuit 4a and a signal detection circuit 4b. The readout circuit 4a switches the thin film transistor 2b2 between an on state and an off state, for example, and includes a plurality of gate drivers 4aa and a row selection circuit 4ab.

[0033] A control signal S1 is input to the row selection circuit 4ab from, for example, an image processing unit (not shown) provided outside the X-ray detector 1. The row selection circuit 4ab inputs the control signal S1 to the corresponding gate driver 4aa according to the scanning direction of the X-ray image. The gate driver 4aa inputs the control signal S1 to the corresponding control line 2c1. The control signal S1 input to the control line 2c1 turns on the thin film transistor 2b2, allowing the charge (image data signal S2) to be read out from the storage capacitor.

[0034] The signal detection circuit 4b includes, for example, a plurality of integral amplifiers 4ba, a plurality of selection circuits 4bb, and a plurality of AD converters 4bc.

[0035] The integrating amplifier 4ba sequentially receives the image data signals S2 from the photoelectric conversion unit 2b. The integrating amplifier 4ba integrates the current flowing within a fixed time and outputs a voltage corresponding to the integrated value to the selection circuit 4bb. The integrating amplifier 4ba converts image data information corresponding to the intensity distribution of the fluorescence generated in the scintillator 3 into potential information.

[0036] The selection circuit 4bb selects the integrating amplifier 4ba to perform reading, and sequentially reads out the image data signal S2 converted into potential information.

[0037] The AD converter 4bc sequentially converts the read image data signals S2 into digital signals. An image processing unit (not shown) provided outside the X-ray detector 1 constructs an X-ray image based on the image data signals S2 converted into digital signals.

[0038] The moisture-proof portion 5 prevents the properties of the scintillator 3 from deteriorating due to moisture in the air. The moisture-proof portion 5 covers the scintillator 3 and the reflective layer 7. There may be a gap between the moisture-proof portion 5 and the reflective layer 7, or the moisture-proof portion 5 and the reflective layer 7 may be in contact with each other. For example, if the vicinity of the periphery of the moisture-proof portion 5 is bonded to the array substrate 2 in an environment where the pressure is reduced below atmospheric pressure, the area covered by the moisture-proof portion 5 is reduced below atmospheric pressure. Therefore, atmospheric pressure can bring the moisture-proof portion 5 and the reflective layer 7 into contact with each other. The moisture-proof portion 5 is made of a material with a low moisture permeability coefficient. The moisture-proof portion 5 is made of a metal such as aluminum. The thickness of the moisture-proof portion 5 is determined taking into account X-ray absorption, rigidity, and the like. The thickness of the moisture-proof portion 5 is, for example, approximately 0.1 mm.

[0039] The adhesive portion 6 is provided between the vicinity of the periphery of the moisture-proof portion 5 and the array substrate 2. The adhesive portion 6 can be formed by curing, for example, an ultraviolet curing adhesive or a two-component mixed adhesive.

[0040] As described above, X-rays 100 incident on the scintillator 3 are converted into fluorescence inside the scintillator 3. The generated fluorescence propagates through the columnar crystals of the scintillator 3 and enters the photoelectric conversion unit 2b. The fluorescence incident on the photoelectric conversion unit 2b is converted into electric charges. The circuit unit 4 reads out image data signals S2 used to construct an X-ray image from the multiple photoelectric conversion units 2b.

[0041] Therefore, if the fluorescence generated inside the scintillator 3 can be efficiently made incident on the photoelectric conversion unit 2b, the sensitivity can be improved, and in turn the quality of the X-ray image can be improved.

[0042] However, because the fluorescence generated inside the scintillator 3 spreads in all directions, it is possible that fluorescence may propagate in the direction opposite to the photoelectric conversion units 2b inside the columnar crystals of the scintillator 3. For this reason, as shown in Figures 1 and 2, a reflective layer 7 that reflects the incident fluorescence toward the scintillator 3 is provided on the side of the scintillator 3 opposite to the side of the multiple photoelectric conversion units 2b.

[0043] FIG. 4 is a schematic cross-sectional view illustrating a reflective layer 207 according to a comparative example. As shown in FIG. 4, the reflective layer 207 according to the comparative example is provided on the side of the scintillator 3 opposite to the photoelectric conversion section 2b side.

[0044] The reflective layer 207 has, for example, a base 207a containing a resin and a plurality of particles 207b. The base 207a holds a plurality of particles 207b in a dispersed state. The base 207a contains a so-called binder resin. The particles 207b may be scatterers that scatter incident fluorescent light, and may be, for example, submicron powders containing titanium dioxide.

[0045] As shown in FIG. 4, fluorescence 200 generated inside the scintillator 3 and propagating through the columnar crystals 3a of the scintillator 3 in the direction opposite to the photoelectric conversion unit 2b enters the reflective layer 207 from the end of the columnar crystals 3a. Since a plurality of particles 207b are dispersed inside the reflective layer 207, when the fluorescence 200 entering the reflective layer 207 enters the particles 207b, the fluorescence 200 is scattered by the particles 207b. A portion of the scattered fluorescence 200a enters the columnar crystals 3a from which the fluorescence 200 was emitted, propagates inside the columnar crystals 3a, and reaches the photoelectric conversion unit 2b. Therefore, the amount of fluorescence entering the photoelectric conversion unit 2b can be increased.

[0046] However, as shown in FIG. 4, the fluorescence 200 incident on the particle 207b is scattered over a relatively wide range. Therefore, it is difficult to make most of the scattered fluorescence 200a incident on the columnar crystal 3a from which the fluorescence 200 is emitted. Furthermore, there is a risk that part of the scattered fluorescence 200a may be incident on a columnar crystal 3a that is near the columnar crystal 3a from which the fluorescence 200 is emitted. If part of the scattered fluorescence 200a is incident on a columnar crystal 3a that is near the columnar crystal 3a from which the fluorescence 200 is emitted, so-called crosstalk may occur, which may degrade the quality of the X-ray image.

[0047] FIG. 5 is a schematic cross-sectional view illustrating the reflective layer 7 according to the present embodiment. 5, the reflective layer 7 is provided on the side of the scintillator 3 opposite to the photoelectric conversion section 2b. For example, the reflective layer 7 can be provided between the scintillator 3 and the moisture-proof section 5. The thickness of the reflective layer 7 can be, for example, about 100 μm.

[0048] The reflective layer 7 includes, for example, a base 7a and a plurality of elements 7b. The base 7a contains a resin and holds the elements 7b in a dispersed state. For example, the base 7a is in the form of a film and contains a binder resin. The resin contained in the base 7a can be, for example, acrylic or styrene.

[0049] A plurality of elements 7b are provided inside the base 7a. The elements 7b reflect incident fluorescence. The elements 7b are translucent and contain a material with a refractive index higher than that of the resin contained in the base 7a. The elements 7b contain, for example, glass such as alkali-free glass. The elements 7b also have a shape that includes a curved surface. For example, the elements 7b illustrated in FIG. 5 are spherical. The elements 7b may also be, for example, columnar, cylindrical, cylindrical lens-like, convex lens-like, or concave lens-like. However, spherical elements 7b make it easier to form the elements 7b. The elements 7b may be solid or hollow.

[0050] If the dimension of the elements 7b is smaller than the thickness of the columnar crystals 3a (the dimension of the columnar crystals 3a in the direction intersecting the direction in which the columnar crystals 3a extend), more elements 7b can be provided near the end of one columnar crystal 3a, which makes it easier for the fluorescence 200 emitted from the columnar crystals 3a to be incident on the elements 7b.

[0051] If the dimensions of the elements 7b are smaller than the dimensions of the gaps between the columnar crystals 3a, the elements 7b may enter the gaps between the columnar crystals 3a, causing crosstalk.

[0052] Therefore, the dimension of the element 7b can be smaller than the thickness of the columnar crystals 3a and larger than the dimension of the gap between the columnar crystals 3a. The dimension of the element 7b can be, for example, 1 μm or more and 10 μm or less.

[0053] 5, it is preferable that the number of elements 7b per unit volume is greater near the end of the reflective layer 7 on the scintillator 3 side than near the end of the reflective layer 7 on the opposite side from the scintillator 3 side. In this way, more elements 7b can be provided near the ends of the columnar crystals 3a. This makes it easier for the fluorescence 200 emitted from the columnar crystals 3a to be incident on the elements 7b.

[0054] The reflective layer 7 can be formed, for example, as follows. First, a plurality of elements 7b are mixed into a molten resin. Next, the resin in which the plurality of elements 7b are mixed is applied to the end of the scintillator 3 opposite to the photoelectric conversion section 2b side. Next, the molten resin is cured to form the reflective layer 7 having the base 7a containing the resin and the plurality of elements 7b provided inside the base 7a.

[0055] At this time, the plurality of elements 7b can be allowed to settle by, for example, lowering the viscosity of the molten resin. In this way, the number of elements 7b per unit volume can be made greater near the end of the reflective layer 7 on the scintillator 3 side than near the end of the reflective layer 7 on the opposite side from the scintillator 3 side.

[0056] Alternatively, the plurality of elements 7b may be scattered on the end of the scintillator 3 opposite to the photoelectric conversion section 2b side, and molten resin may be supplied to the scattered plurality of elements 7b. Alternatively, a resin containing many elements 7b may be applied to the end of the scintillator 3 opposite to the photoelectric conversion section 2b side, and molten resin may be supplied to this. Even in these ways, the number of elements 7b per unit volume can be made greater near the end of the reflective layer 7 on the scintillator 3 side than near the end of the reflective layer 7 on the opposite side from the scintillator 3 side.

[0057] FIG. 6 is a schematic cross-sectional view illustrating the effect of the element 7b. As shown in FIG. 6 , fluorescence 200 generated inside the columnar crystals 3a of the scintillator 3 and emitted from the ends of the columnar crystals 3a into the interior of the reflective layer 7 is incident on an element 7b provided near the ends of the columnar crystals 3a. According to Snell's law, the fluorescence 200 incident on the element 7b is reflected by the surface of the element 7b or enters the interior of the element 7b. For example, fluorescence 200b reflected by the surface of the element 7b provided near the ends of the columnar crystals 3a is likely to enter the columnar crystals 3a. Furthermore, for example, fluorescence 200 incident on the interior of the element 7b provided near the ends of the columnar crystals 3a is reflected at the interface between the surface of the element 7b and the base 7a. Fluorescence 200b reflected at the interface between the surface of the element 7b and the base 7a is likely to enter the columnar crystals 3a.

[0058] Therefore, if the reflective layer 7 is provided with elements 7b containing a material that is translucent and has a refractive index higher than that of the resin contained in the base 7a, the fluorescence 200 that has entered the reflective layer 7 can be made to enter the columnar crystals 3a of the scintillator 3 more efficiently than in a reflective layer 207 provided with particles 207b containing titanium dioxide that scatter the incident fluorescence 200. As a result, the amount of fluorescence that reaches the photoelectric conversion unit 2 increases, thereby improving sensitivity and ultimately the quality of X-ray images.

[0059] FIG. 7 is a schematic cross-sectional view illustrating a reflective layer 17 according to another embodiment. 7, the reflective layer 17 has, for example, a base 7a and a plurality of elements 17b. That is, the reflective layer 17 can be obtained by replacing the elements 7b of the reflective layer 7 with the elements 17b.

[0060] Furthermore, the element 17b has, for example, an element 7b (corresponding to an example of the first portion) and a reflective portion 7ba (corresponding to an example of the second portion). That is, the element 17b can be the above-mentioned element 7b to which the reflective portion 7ba has been added. The reflective portion 7ba is in the form of a film, and covers a partial area of ​​the surface of the element 7b. The reflective portion 7ba can contain a metal that has a high reflectivity for the fluorescent light 200. The reflective portion 7ba can contain a metal such as an aluminum alloy, a palladium alloy, platinum, or a silver alloy.

[0061] The element 17b can be formed by depositing a film on a partial area of ​​the surface of the element 7b using a deposition method such as sputtering.

[0062] 7, if an element 17b having a reflecting portion 7ba is provided, the fluorescence 200 incident on the element 17b can be reflected by the reflecting portion 7ba. Therefore, the fluorescence 200 can be reflected efficiently, which further increases the amount of fluorescence that can be incident on the columnar crystals 3a of the scintillator 3 and, in turn, the amount of fluorescence that reaches the photoelectric conversion unit 2. As a result, the sensitivity can be further improved, and, in turn, the quality of the X-ray image can be further improved.

[0063] FIG. 8 is a schematic cross-sectional view illustrating a reflective layer 27 according to another embodiment. 8, the reflective layer 27 includes, for example, a base 7a and a plurality of elements 17c. That is, the reflective layer 27 can be obtained by replacing the elements 17b of the reflective layer 17 with the elements 17c.

[0064] Element 17c has only the reflective portion 7ba described above. Element 17c can be formed by, for example, forming a film on a partial area of ​​the surface of a particle containing an easily soluble material such as a resin by a film-forming method such as sputtering, and then dissolving the particle.

[0065] 8, even when only the reflecting portion 7ba is provided, the fluorescence 200 incident on the reflecting portion 7ba can be reflected. Therefore, the fluorescence 200 can be reflected efficiently, and the amount of fluorescence that can be incident on the columnar crystals 3a of the scintillator 3 and thus the amount of fluorescence that reaches the photoelectric conversion portion 2 can be increased. As a result, the sensitivity can be improved, and ultimately the quality of the X-ray image can be improved.

[0066] 7, if the element 7b is provided, the fluorescence 200 incident on the element 7b and the fluorescence 200b emitted from the element 7b can be refracted and collected. Therefore, if the element 7b is provided, it becomes easy to increase the amount of fluorescence that can be incident on the columnar crystals 3a of the scintillator 3, and therefore the amount of fluorescence that reaches the photoelectric conversion unit 2.

[0067] Furthermore, while FIG. 8 illustrates the reflective portion 7ba having a curved shape, the reflective portion may have a bent shape such as an L-shape, or a shape such as a rectangular parallelepiped. That is, the reflective portion may have a concave curved surface or a flat surface. If the reflective portion has a concave curved surface or a flat surface, it is easier to increase the amount of fluorescence that can be incident on the columnar crystals 3a of the scintillator 3 compared to a reflective portion having only a convex curved surface, such as the particles 207b containing titanium dioxide. In this case, if the reflective portion has a concave curved surface, the incident fluorescence 200 can be concentrated, making it even easier to increase the amount of fluorescence that can be incident on the columnar crystals 3a of the scintillator 3.

[0068] Although the above describes an example in which each of the elements 7b, 17b, and 17c is provided, at least one of the elements 7b, 17b, and 17c may be provided. That is, the element can be made to contain at least one of a material that is translucent and has a refractive index higher than the refractive index of the resin contained in the base portion 7a, and a metal. In this case, the element may comprise a metal and have a concave curved surface and / or a flat surface.

[0069] FIG. 9 is a schematic cross-sectional view illustrating a reflective layer 37 according to another embodiment. 9, the reflective layer 37 includes, for example, a base 7a, a plurality of elements 17b, and a plurality of particles 17d. That is, the reflective layer 37 may be the reflective layer 17 described above, to which a plurality of particles 17d has been added. The particles 17d may include a light-scattering material. The particles 17d may be, for example, a submicron powder containing titanium dioxide. As described above, if the element 17b is provided, the fluorescent light 200 incident on the element 17b can be reflected, and the reflected fluorescent light 200b can be made to enter the columnar crystals 3a.

[0070] Furthermore, if particles 17d are further provided, the fluorescence 200 incident on the particles 17d can be scattered and made to enter the columnar crystals 3a or the elements 17b, as shown in Fig. 9. In this case, the fluorescence 200 incident on the elements 17b via the particles 17d can be made to enter the columnar crystals 3a in the same way as the fluorescence 200 directly incident on the elements 17b.

[0071] Therefore, if a plurality of elements 17b and a plurality of particles 17d are provided, the amount of fluorescence that can be incident on the columnar crystals 3a of the scintillator 3 can be effectively increased.

[0072] Although the above example shows the case where the elements 17b and the particles 17d are provided, it is also possible to provide at least one of the elements 7b, 17b, and 17c and the particles 17d.

[0073] Although the embodiments have been described above, the present invention is not limited to these descriptions. With respect to the above-described embodiments, those skilled in the art may add, delete, or modify components as appropriate, or add, omit, or change processes or conditions as appropriate, and these modifications are also within the scope of the present invention as long as they retain the characteristics of the present invention. Furthermore, the elements of each of the above-described embodiments can be combined to the greatest extent possible, and such combinations are also included within the scope of the present invention as long as they include the features of the present invention.

[0074] The following are additional notes regarding the above-described embodiment.

[0075] (Appendix 1) an array substrate having a plurality of photoelectric conversion units; a scintillator that is provided on the plurality of photoelectric conversion units and converts incident radiation into fluorescence; a reflective layer provided on the side of the scintillator opposite to the side of the plurality of photoelectric conversion units, the reflective layer including a base containing a resin and a plurality of elements provided inside the base; Equipped with The element is a radiation detector that has optical transparency and includes at least one of a material having a refractive index higher than the refractive index of the resin contained in the base and a metal.

[0076] (Appendix 2) 2. The radiation detector of claim 1, wherein the element comprises glass and has a shape that includes a curved surface.

[0077] (Appendix 3) The element has a first portion and a second portion provided on a partial area of ​​a surface of the first portion, the first portion has the light-transmitting property and includes the material having a refractive index higher than a refractive index of the resin included in the base; 3. The radiation detector of claim 1, wherein the second portion includes the metal.

[0078] (Appendix 4) 2. The radiation detector of claim 1, wherein the element includes the metal and has at least one of a concave curved surface and a flat surface.

[0079] (Appendix 5) 5. The radiation detector according to claim 1, wherein the reflective layer further comprises a plurality of particles containing a light-scattering material.

[0080] (Appendix 6) the scintillator includes a plurality of columnar crystals; 6. The radiation detector according to any one of claims 1 to 5, wherein the dimensions of the elements are smaller than the thickness of the columnar crystals and larger than the dimensions of the gaps between the columnar crystals.

[0081] (Appendix 7) 7. A radiation detector according to any one of appendices 1 to 6, wherein the number of the elements per unit volume is greater near the end of the reflective layer on the scintillator side than near the end of the reflective layer on the opposite side from the scintillator side. [Explanation of symbols]

[0082] 1 X-ray detector, 2 array substrate, 2a substrate, 2b photoelectric conversion section, 3 scintillator, 3a columnar crystal, 7 reflective layer, 7a base, 7b element, 7ba reflective section, 17 reflective layer, 17b element, 17c element, 17d particle, 27 reflective layer, 37 reflective layer, 200 fluorescence, 200a fluorescence, 200b fluorescence

Claims

1. an array substrate having a plurality of photoelectric conversion units; a scintillator that is provided on the plurality of photoelectric conversion units and converts incident radiation into fluorescence; a reflective layer provided on the side of the scintillator opposite to the side of the plurality of photoelectric conversion units, the reflective layer including a base containing a resin and a plurality of elements provided inside the base; Equipped with The element is a radiation detector that has optical transparency and includes at least one of a material having a refractive index higher than the refractive index of the resin contained in the base and a metal.

2. 10. The radiation detector of claim 1, wherein the element comprises glass and has a shape that includes a curved surface.

3. The element has a first portion and a second portion provided on a partial area of ​​a surface of the first portion, the first portion has the light-transmitting property and includes the material having a refractive index higher than a refractive index of the resin included in the base; The radiation detector according to claim 1 or 2, wherein the second portion includes the metal.

4. The radiation detector according to claim 1 , wherein the element includes the metal and has at least one of a concave curved surface and a flat surface.

5. 3. The radiation detector according to claim 1, wherein the reflective layer further comprises a plurality of particles containing a light-scattering material.

6. the scintillator includes a plurality of columnar crystals; 3. The radiation detector according to claim 1, wherein the size of the element is smaller than the thickness of the columnar crystals and larger than the size of the gaps between the columnar crystals.

7. 3. The radiation detector according to claim 1, wherein the number of the elements per unit volume is greater near the end of the reflective layer on the scintillator side than near the end of the reflective layer on the opposite side from the scintillator side.

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