JP7374862B2 - radiation detector - Google Patents

Description

Embodiments of the invention relate to radiation detectors.

For example, an X-ray detector (X-ray flat detector) is known as a radiation detector. The X-ray detection module of the X-ray detector includes a scintillator layer that converts X-rays into fluorescence and a photoelectric conversion board that converts the fluorescence into electrical signals. The scintillator layer contains, for example, cesium iodide (CsI). In addition, in order to increase fluorescence utilization efficiency and improve sensitivity characteristics, the X-ray detection module may further include a light reflection layer provided on the scintillator layer.

Here, in order to suppress deterioration of characteristics due to water vapor or the like, the scintillator layer and the light reflection layer need to be isolated from the external atmosphere. Therefore, as a structure that can obtain high moisture-proof performance, a technique has been proposed in which the scintillator layer and the light-reflecting layer are covered with a hat-shaped moisture-proof cover, and the periphery of the moisture-proof cover is bonded to the photoelectric conversion substrate.

Japanese Patent Application Publication No. 2015-219208 Japanese Patent Application Publication No. 2009-128023

This embodiment provides a radiation detector that can suppress moisture permeation into the scintillator layer.

A radiation detector according to one embodiment includes:
a flexible base material including a first main surface and a second main surface opposite to the first main surface; a plurality of photoelectric conversion elements located above the second main surface of the base material; , a scintillator layer provided on the photoelectric conversion substrate and facing the second main surface and the plurality of photoelectric conversion elements, and facing the first main surface of the base material, a support substrate that supports the photoelectric conversion substrate and has an elastic modulus higher than that of the base material; and a support substrate that is located between the first main surface of the base material and the support substrate; a frame-shaped adhesive material to which a substrate is bonded; a space between the base material and the supporting substrate is a space whose pressure is reduced from atmospheric pressure; and the adhesive material is a space between the base material and the supporting substrate; The scintillator layer also maintains the space and is located outside the scintillator layer in plan view.

Moreover, the radiation detector according to one embodiment is
a flexible base material including a first main surface and a second main surface opposite to the first main surface; a plurality of photoelectric conversion elements located above the second main surface of the base material; a scintillator layer provided on the photoelectric conversion substrate and facing the second main surface and the plurality of photoelectric conversion elements; a support substrate supporting a photoelectric conversion substrate; a dry gas filled in a space between the base material and the support substrate ; and a dry gas located between the first main surface of the base material and the support substrate; a frame-shaped adhesive material bonding the base material and the support substrate, the adhesive material holding the space together with the base material and the support substrate and being located outside the scintillator layer in plan view. are doing.

FIG. 1 is a sectional view showing an X-ray detector according to one embodiment. FIG. 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. FIG. 3 is an enlarged sectional view showing a part of the X-ray detection module of the X-ray detector. FIG. 4 is a plan view showing a part of the X-ray detector. FIG. 5 is a cross-sectional view of a portion of the X-ray detector taken along line VV. FIG. 6 is a plan view showing a part of an X-ray detector according to a modification of the above embodiment.

An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the disclosure is merely an example, and any modifications that can be easily made by those skilled in the art while maintaining the gist of the invention are naturally included within the scope of the present invention. In addition, in order to make the explanation clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual aspect, but these are only examples, and the interpretation of the present invention is It is not limited. In addition, in this specification and each figure, the same elements as those described above with respect to the previously shown figures are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

FIG. 1 is a sectional view showing an X-ray detector 1 according to this embodiment. The X-ray detector 1 is an X-ray image detector, and is an X-ray flat detector using an X-ray detection panel.
As shown in FIG. 1, the X-ray detector 1 includes an X-ray detection module 10, a support substrate 12, a circuit board 11, spacers 9a, 9b, 9c, 9d, a housing 51, an FPC (flexible printed circuit board) 2e1, an incident It is equipped with windows 52 and the like. The X-ray detection module 10 includes an X-ray detection panel PNL and a moisture-proof cover 7. The X-ray detection panel PNL is located between the support substrate 12 and the moisture-proof cover 7. The moisture-proof cover 7 faces the entrance window 52.

The entrance window 52 is attached to the opening of the housing 51. The entrance window 52 transmits X-rays. Therefore, the X-rays pass through the entrance window 52 and enter the X-ray detection module 10. The entrance window 52 is formed into a plate shape and has a function of protecting the inside of the housing 51. It is desirable that the entrance window 52 be made of a thin material with low X-ray absorption. In this embodiment, the entrance window 52 is made of carbon-fiber-reinforced plastic (CFRP). Thereby, scattering of X-rays and attenuation of the X-ray dose that occur at the entrance window 52 can be reduced. Then, a thin and light X-ray detector 1 can be realized.
The X-ray detection module 10, the support substrate 12, the circuit board 11, the FPC 2e1, and the like are housed inside a space surrounded by the casing 51 and the entrance window 52.

Since the X-ray detection module 10 is constructed by laminating thin members, it is light and has low mechanical strength. Therefore, the X-ray detection panel PNL (X-ray detection module 10) is fixed to the support substrate 12. The support substrate 12 is formed into a plate shape of, for example, an aluminum alloy, and has the strength (modulus of elasticity) necessary to stably hold the X-ray detection panel PNL. Thereby, it is possible to suppress damage to the X-ray detection panel PNL when vibration or shock is applied to the X-ray detector 1 from the outside. Note that the support substrate 12 may be formed of a material having low moisture permeability and high elastic modulus, and may be formed of a material such as stainless steel, glass, or CFRP.

A circuit board 11 is fixed to the other surface of the support substrate 12 via spacers 9a and 9b. For example, when the support substrate 12 is mainly made of metal, the electrical insulation distance from the support substrate 12 to the circuit board 11 can be maintained by using the spacers 9a and 9b.
The circuit board 11 is fixed to the inner surface of the casing 51 via spacers 9c and 9d. By using the spacers 9c and 9d, it is possible to maintain an electrically insulating distance from the casing 51, which is mainly made of metal, to the circuit board 11. The housing 51 supports the support board 12 and the like via the circuit board 11 and spacers 9a, 9b, 9c, and 9d.

A connector corresponding to the FPC 2e1 is mounted on the circuit board 11, and the FPC 2e1 is electrically connected to the circuit board 11 via the connector. A thermocompression bonding method using ACF (anisotropic conductive film) is used to connect the FPC 2e1 and the X-ray detection panel PNL. This method ensures electrical connection between the plurality of fine pads of the X-ray detection panel PNL and the plurality of fine pads of the FPC 2e1.

As described above, the circuit board 11 is electrically connected to the X-ray detection panel PNL via the connector, FPC 2e1, etc. The circuit board 11 electrically drives the X-ray detection panel PNL and electrically processes output signals from the X-ray detection panel PNL.

FIG. 2 is a perspective view showing the support substrate 12, the X-ray detection panel PNL, the circuit board 11, and the plurality of FPCs 2e1 and 2e2 of the X-ray detector 1 of this embodiment. Note that FIG. 2 does not show all the members of the X-ray detector 1. Illustrations of some members of the X-ray detector 1, such as a sealing part to be described later, are omitted in FIG.

As shown in FIG. 2, the X-ray detection panel PNL includes a photoelectric conversion substrate 2, a scintillator layer 5, and the like. The photoelectric conversion substrate 2 includes a base material 2a, a photoelectric conversion section 2b, a plurality of control lines (or gate lines) 2c1, a plurality of data lines (or signal lines) 2c2, and the like. Note that the number, arrangement, etc. of the photoelectric conversion section 2b, control line 2c1, and data line 2c2 are not limited to the example in FIG. 2.

The plurality of control lines 2c1 extend in the row direction and are arranged at predetermined intervals in the column direction. The plurality of data lines 2c2 extend in the column direction, intersect with the plurality of control lines 2c1, and are arranged at predetermined intervals in the row direction.

The plurality of photoelectric conversion parts 2b are provided on one main surface side of the base material 2a. The photoelectric conversion section 2b is provided in a rectangular region defined by a control line 2c1 and a data line 2c2. One photoelectric conversion unit 2b corresponds to one pixel of an X-ray image. The plurality of photoelectric conversion units 2b are arranged in a matrix. From the above, the photoelectric conversion section 2b is an array substrate.

Each photoelectric conversion unit 2b includes a photoelectric conversion element 2b1 and a TFT (thin film transistor) 2b2 as a switching element. The TFT 2b2 is connected to one corresponding control line 2c1 and one corresponding data line 2c2. The photoelectric conversion element 2b1 is electrically connected to the TFT 2b2.

The control line 2c1 is electrically connected to the circuit board 11 via the FPC 2e1. The circuit board 11 provides 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 accumulated 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.

The X-ray detector 1 further includes an image transmission section 4. Image transmission section 4 is connected to circuit board 11 via wiring 4a. Note that the image transmission section 4 may be incorporated into the circuit board 11. The image transmission unit 4 generates an X-ray image based on image data signals converted into digital signals by a plurality of analog-to-digital converters (not shown). The generated X-ray image data is output from the image transmission section 4 to an external device.

FIG. 3 is an enlarged sectional view showing a part of the X-ray detection module 10 of the X-ray detector 1 according to this embodiment.
As shown in FIG. 3, the photoelectric conversion substrate 2 includes a base material 2a, a plurality of photoelectric conversion parts 2b, and insulating layers 21, 22, 23, 24, and 25. The plurality of photoelectric conversion units 2b are located in the detection area DA. Each photoelectric conversion section 2b includes a photoelectric conversion element 2b1 and a TFT 2b2.

TFT2b2 has a gate electrode GE, a semiconductor layer SC, a source electrode SE, and a drain electrode DE. The photoelectric conversion element 2b1 is composed of a photodiode. Note that the photoelectric conversion element 2b1 may be configured to convert light into charges.

The base material 2a has a plate-like shape and is made of an insulating material. The planar shape of the base material 2a is, for example, a quadrilateral. The base material 2a has flexibility and can be bent. Examples of the material for the base material 2a include polyimide (PI), which is a resin. The base material 2a has a first main surface M1 and a second main surface M2 opposite to the first main surface M1. The plurality of photoelectric conversion units 2b (photoelectric conversion elements 2b1 and TFTs 2b2) are located above the second main surface M2 of the base material 2a.

The insulating layer 21 is provided on the base material 2a. A gate electrode GE is formed on the insulating layer 21. The gate electrode GE is electrically connected to the 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 and polycrystalline silicon as a polycrystalline semiconductor.

A source electrode SE and a drain electrode DE are provided on the insulating layer 22 and the semiconductor layer SC. The gate electrode GE, source electrode SE, drain electrode DE, the control line 2c1, and the data line 2c2 are formed using a low-resistance metal such as aluminum or chromium.

Source electrode SE is electrically connected to the source region of semiconductor layer SC. Further, the source electrode SE is electrically connected to the data line 2c2. The drain electrode DE is electrically connected to the drain region of the semiconductor layer SC.

The 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. The 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. The 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 made of an insulating material such as an inorganic insulating material or an organic insulating material. Inorganic insulating materials include oxide insulating materials, nitride insulating materials, and oxynitride insulating materials. Examples of organic insulating materials include resins.

The scintillator layer 5 is provided on the photoelectric conversion substrate 2 (the plurality of photoelectric conversion units 2b). The scintillator layer 5 faces the second main surface M2 of the base material 2a and the plurality of photoelectric conversion parts 2b. The scintillator layer 5 is located at least in the detection area DA and covers above the plurality of photoelectric conversion units 2b. The scintillator layer 5 is configured to convert incident X-rays into light (fluorescence).

Note that the photoelectric conversion element 2b1 converts light incident from the scintillator layer 5 into charges. The converted charges are accumulated in the photoelectric conversion element 2b1. The TFT 2b2 can switch between charging the photoelectric conversion element 2b1 and discharging from the photoelectric conversion element 2b1. Note that when the self-capacitance of the photoelectric conversion element 2b1 is insufficient, the photoelectric conversion board 2 may further include a capacitor (storage capacitor), and the charge converted by the photoelectric conversion element 2b1 may be stored in the capacitor.

The scintillator layer 5 is formed of thallium-activated cesium iodide (CsI:Tl). If the scintillator layer 5 is formed using a vacuum evaporation method, the scintillator layer 5 made of an aggregate of a plurality of columnar crystals can be obtained. The thickness of the scintillator layer 5 is, for example, 600 μm. At the outermost surface of the scintillator layer 5, the thickness of the columnar crystals of the scintillator layer 5 is 8 to 12 μm.

The material forming the scintillator layer 5 is not limited to CsI:Tl. The scintillator layer 5 may be formed of thallium-activated sodium iodide (NaI:Tl), sodium-activated cesium iodide (CsI:Na), europium-activated cesium bromide (CsBr:Eu), sodium iodide (NaI), etc. good.

Note that when forming the scintillator layer 5 using the vacuum evaporation method, a mask having an opening is used. In this case, the scintillator layer 5 is formed on the photoelectric conversion substrate 2 in a region facing the opening. Furthermore, the scintillator material by vapor deposition is also deposited on the surface of the mask. The scintillator material is also deposited near the opening of the mask, and crystals grow so as to gradually protrude into the opening. When the crystal protrudes from the mask into the opening, deposition of the scintillator material onto the photoelectric conversion substrate 2 is suppressed in the vicinity of the opening. Therefore, as shown in FIG. 2, the thickness of the scintillator layer 5 near its periphery gradually decreases toward the outside.

Alternatively, the scintillator layer 5 may include a plurality of scintillator sections arranged in a matrix, provided one-to-one on the photoelectric conversion section 2b, and each having a quadrangular prism shape. When forming such a scintillator layer 5, a scintillator material in which gadolinium oxysulfide (Gd ₂ O ₂ S) phosphor particles are mixed with a binder material is applied onto the photoelectric conversion substrate 2, and the scintillator material is baked and hardened. let Thereafter, dicing is performed using a dicer to form grid-like grooves in the scintillator material. In the above case, air or an inert gas such as nitrogen (N ₂ ) for preventing oxidation is sealed between the plurality of scintillator sections. Alternatively, the space between the plurality of scintillator parts may be set to a space whose pressure is lower than atmospheric pressure.

In this embodiment, the X-ray detection panel PNL further includes a light reflection layer 6. The light reflecting layer 6 is provided on the scintillator layer 5. In other words, the light reflecting layer 6 is provided on the X-ray incident side of the scintillator layer 5. The light reflection layer 6 is located at least in the detection area DA and covers the upper surface of the scintillator layer 5. The light reflecting layer 6 is provided to increase the efficiency of light (fluorescence) use and improve sensitivity characteristics. That is, the light reflection layer 6 reflects the light that is generated in the scintillator layer 5 and is directed toward the side opposite to the side where the photoelectric conversion section 2b is provided, so that the light is directed toward the photoelectric conversion section 2b. However, the light reflecting layer 6 is not necessarily required, and may be provided depending on the sensitivity characteristics required for the X-ray detection module 10.

For example, a coating material containing a mixture of light-scattering particles such as titanium oxide (TiO ₂ ), a resin, and a solvent is coated on the scintillator layer 5, and then the light-reflecting layer 6 is formed by drying the coating material. can be formed.

Note that the structure of the light-reflecting layer 6 and the method of manufacturing the light-reflecting layer 6 are not limited to the above examples, and can be modified in various ways. For example, the light reflecting layer 6 may be formed by forming a layer made of a metal with high light reflectivity such as a silver alloy or aluminum on the scintillator layer 5. Alternatively, the light reflective layer 6 may be formed by providing on the scintillator layer 5 a sheet whose surface includes a metal layer with high light reflectance such as silver alloy or aluminum, or a resin sheet containing light scattering particles. good.

Note that when a paste coating material is applied onto the scintillator layer 5 and the coating material is dried, the coating material shrinks as it dries, so tensile stress is applied to the scintillator layer 5 and the scintillator layer 5 becomes photosensitive. It may peel off from the conversion board 2. Therefore, it is preferable to provide a sheet-like light reflection layer 6 on the scintillator layer 5. In this case, the light reflective layer 6 can be bonded onto the scintillator layer 5 using, for example, double-sided tape, but it is preferable to place the light reflective layer 6 on the scintillator layer 5. By placing the sheet-shaped light reflective layer 6 on the scintillator layer 5, peeling of the scintillator layer 5 from the photoelectric conversion substrate 2 due to expansion or contraction of the light reflective layer 6 can be easily suppressed.

The moisture-proof cover (moisture-proof part) 7 is provided on the photoelectric conversion substrate 2 , the scintillator layer 5 , and the light reflection layer 6 . A moisture-proof cover (moisture-proof part) 7 covers the scintillator layer 5 and the light reflection layer 6. The moisture-proof cover 7 is provided to suppress deterioration of the characteristics of the light reflection layer 6 and the characteristics of the scintillator layer 5 due to moisture contained in the air. The moisture-proof cover 7 completely covers the exposed portion of the scintillator layer 5. A gap may be left between the moisture-proof cover 7 and the light-reflecting layer 6, etc., or the moisture-proof cover 7 may be in contact with the light-reflecting layer 6, etc.

The moisture-proof cover 7 is formed of a sheet containing metal. Examples of the metal include metals containing aluminum, metals containing copper, metals containing magnesium, metals containing tungsten, stainless steel, Kovar, and the like. When the moisture-proof cover 7 contains metal, the moisture-proof cover 7 can prevent or significantly suppress the permeation of moisture.

Further, the moisture-proof cover 7 may be formed of a laminated sheet in which a resin layer and a metal layer are laminated. In this case, the resin layer can be formed of a material such as polyimide resin, epoxy resin, polyethylene terephthalate resin, Teflon (registered trademark), low density polyethylene, high density polyethylene, elastic rubber, or the like. The metal layer can include, for example, the metals described above. The metal layer can be formed using a sputtering method, a lamination method, or the like.

In this case, it is preferable to provide the metal layer closer to the scintillator layer 5 than the resin layer. Since the metal layer can be covered with the resin layer, damage to the metal layer due to external force or the like can be suppressed. Furthermore, if the metal layer is provided closer to the scintillator layer 5 than the resin layer, deterioration of the characteristics of the scintillator layer 5 due to moisture permeation through the resin layer can be suppressed.

Examples of the moisture-proof cover 7 include a sheet including a metal layer, a sheet including an inorganic insulating layer, a laminated sheet in which a resin layer and a metal layer are laminated, and a laminated sheet in which a resin layer and an inorganic insulating layer are laminated. can. From the above, the inorganic layer of the moisture-proof cover 7 is not limited to a metal layer, but may be an inorganic insulating layer. Alternatively, the moisture-proof cover 7 may have both a metal layer and an inorganic insulating layer. The inorganic insulating layer can be formed of a layer containing silicon oxide, aluminum oxide, or the like. The inorganic insulating layer can be formed using a sputtering method or the like.

When forming the moisture-proof cover 7 with a laminated sheet including a metal layer, the thickness of the resin layer can be made substantially the same as the thickness of the metal layer, for example. If the moisture-proof cover 7 includes a resin layer having such a thickness, the rigidity of the moisture-proof cover 7 can be increased, so that the occurrence of pinholes in the moisture-proof cover 7 can be suppressed during the manufacturing process. . Note that, in general, the linear expansion coefficient of resin is larger than that of metal, so if the thickness of the resin layer is made too large, it becomes difficult to follow deformation such as warpage of the photoelectric conversion substrate 2. Therefore, in the moisture-proof cover 7, the thickness of the resin layer is preferably equal to or less than the thickness of the metal layer.

Further, the thickness of the moisture-proof cover 7 can be determined in consideration of X-ray absorption, rigidity (modulus of elasticity), and the like. In this case, as the thickness of the moisture-proof cover 7 increases, the amount of X-rays absorbed by the moisture-proof cover 7 increases. On the other hand, as the thickness of the moisture-proof cover 7 is reduced, the rigidity of the moisture-proof cover 7 decreases, and the moisture-proof cover 7 becomes more easily damaged.

For example, if the thickness of the moisture-proof cover 7 is less than 10 μm, the rigidity of the moisture-proof cover 7 will become too low, and there is a risk that pinholes will be formed in the moisture-proof cover 7 due to damage caused by external force, and leaks may occur. When the thickness of the moisture-proof cover 7 exceeds 50 μm, the rigidity of the moisture-proof cover 7 becomes too high, and the ability to follow irregularities at the upper end of the scintillator layer 5 becomes poor. Therefore, it may be difficult to confirm the gaps and leak paths described above. Furthermore, there is a possibility that it will be difficult to follow the deformation of the photoelectric conversion substrate 2.

Therefore, the thickness of the moisture-proof cover 7 is preferably 10 μm or more and 50 μm or less. In this case, the moisture-proof cover 7 can be formed of, for example, aluminum foil (aluminum laminate film) with a thickness of 10 to 50 μm. If the aluminum foil has a thickness of 10 to 50 μm, the amount of X-rays transmitted can be increased by about 20 to 30% compared to an aluminum foil with a thickness of 100 μm. Furthermore, if the aluminum foil is used with a thickness of 10 to 50 μm, the above-mentioned leakage can be suppressed, and the above-mentioned gaps and leak paths can be easily confirmed. Furthermore, the moisture-proof cover 7 can follow deformations such as warping of the photoelectric conversion substrate 2.

In order to reduce the thermal expansion and contraction of the metal, it is preferable that the thickness of the metal such as aluminum is 30 μm or less. In this case, it is preferable that the moisture-proof cover 7 includes aluminum foil with a thickness of 10 to 30 μm.

The moisture-proof cover 7 according to this embodiment is an aluminum laminate film with a thickness of 10 to 50 μm. For example, when the moisture-proof cover 7 is formed of an aluminum laminate film, the moisture-proof cover 7 has flexibility and can accommodate curving. In that case, the elastic modulus of the moisture-proof cover 7 is lower than the elastic modulus of the support substrate 12. The flexible moisture-proof cover 7 can contribute to forming the flexible X-ray detection module 10 together with the base material 2a.

Here, since irradiating a large amount of X-rays to the human body has an adverse effect on health, the amount of X-ray irradiation to the human body is suppressed to the necessary minimum. Therefore, in the case of the X-ray detector 1 used for medical purposes, the intensity of the emitted X-rays may be low, and the intensity of the X-rays transmitted through the moisture-proof cover 7 may be extremely low. Since the moisture-proof cover 7 is a sheet having a thickness of 10 to 50 μm, it is possible to take an X-ray image even when the intensity of the irradiated X-rays is low.

FIG. 4 is a plan view showing a part of the X-ray detector 1. In FIG. 4, the scintillator layer 5 is marked with diagonal lines going upward to the right, and the sealing portion 8 and the adhesive 3 are each marked with diagonal lines falling downward to the right. FIG. 5 is a sectional view showing a part of the X-ray detector 1 along line VV.

As shown in FIGS. 4 and 5, the photoelectric conversion substrate 2 includes a detection area DA, a frame-shaped first non-detection area NDA1 located around the detection area DA, and a first non-detection area NDA1 outside the first non-detection area NDA1. 2 non-detection area NDA2. In this embodiment, the second non-detection area NDA2 has a frame shape.

The scintillator layer 5 is located at least in the detection area DA. The light reflecting layer 6 is located at least in the detection area DA. In this embodiment, the light reflecting layer 6 does not cover the side surface 5a of the scintillator layer 5 at all. However, the light reflecting layer 6 may cover a part of the side surface 5a of the scintillator layer 5, or may cover the entire side surface 5a of the scintillator layer 5.

The X-ray detector 1 further includes a sealing part 8. The sealing portion 8 is provided around the scintillator layer 5 . The sealing portion 8 has a frame-like shape and extends continuously around the scintillator layer 5 . In this embodiment, the sealing part 8 is located in the first non-detection area NDA1. The sealing part 8 joins the photoelectric conversion substrate 2 (for example, the above-mentioned insulating layer 25) and the moisture-proof cover 7.

The moisture-proof cover 7 seals the scintillator layer 5 and the light reflection layer 6 together with the photoelectric conversion substrate 2 . In this embodiment, the moisture-proof cover 7 seals the scintillator layer 5 and the light reflection layer 6 together with the photoelectric conversion substrate 2 and the sealing part 8 . In the plan view shown in FIG. 4, the moisture-proof cover 7 is located in the detection area DA and the first non-detection area NDA1, and completely covers the scintillator layer 5. As shown in FIG. 5, the portion of the scintillator layer 5 that is not covered with the photoelectric conversion substrate 2 and the sealing part 8 is completely covered with the moisture-proof cover 7.

The moisture-proof cover 7 is joined to the outer surface 8a of the sealing part 8. The moisture-proof cover 7 covers at least a portion of the sealing portion 8. Note that it is advantageous to completely cover the sealing portion 8 with the moisture-proof cover 7 because the moisture permeation path becomes smaller. For example, if the moisture-proof cover 7 and the sealing part 8 are bonded in an environment where the pressure is lower than atmospheric pressure, the moisture-proof cover 7 can be brought into contact with the light reflective layer 6 and the like.

Further, in general, the scintillator layer 5 has voids of about 10 to 40% of its volume. Therefore, if gas is contained in the gap, the gas may expand and damage the moisture-proof cover 7 when the X-ray detector 1 is transported by aircraft or the like. If the moisture-proof cover 7 and the sealing part 8 are bonded in an environment with a pressure lower than atmospheric pressure, the Even if there is, damage to the moisture-proof cover 7 can be suppressed. From the above, it is preferable that the pressure in the space defined by the sealing part 8 and the moisture-proof cover 7 be lower than atmospheric pressure.

When the thickness of the moisture-proof cover 7 is reduced, the rigidity (modulus of elasticity) of the moisture-proof cover 7 decreases. Therefore, when forming a three-dimensional moisture-proof cover 7 by providing a brim portion or the like on the moisture-proof cover 7, for example, when press-molding metal foil, cracks and the like are likely to occur. On the other hand, the vicinity of the periphery of the sheet-shaped moisture-proof cover 7 is joined to the outer surface 8a of the sealing portion 8. Therefore, there is no need to process the moisture-proof cover 7 into a three-dimensional shape in advance, and the sheet-like moisture-proof cover 7 can be directly joined to the outer surface 8a of the sealing portion 8. As a result, even if the thickness of the moisture-proof cover 7 is 10 μm or more and 50 μm or less, the occurrence of defects such as cracks in the moisture-proof cover 7 can be suppressed. Moreover, the moisture-proof cover 7 can be deformed following the warpage of the photoelectric conversion board 2.

Furthermore, as will be described later, by heating the vicinity of the periphery of the moisture-proof cover 7, the vicinity of the periphery of the moisture-proof cover 7 and the sealing portion 8 are joined. In this case, when the temperature near the periphery of the moisture-proof cover 7 and the temperature of the sealing part 8 decrease, thermal stress is generated between the vicinity of the periphery of the moisture-proof cover 7 and the sealing part 8. If thermal stress is generated between the vicinity of the periphery of the moisture-proof cover 7 and the sealing part 8, there is a possibility that peeling will occur between the vicinity of the periphery of the moisture-proof cover 7 and the sealing part 8. If peeling occurs, there is a risk that the moisture-proof performance will be significantly reduced. Since the thickness of the moisture-proof cover 7 is set to be 10 μm or more and 50 μm or less, the moisture-proof cover 7 easily stretches when thermal stress occurs. Therefore, thermal stress can be alleviated, so that peeling of the moisture-proof cover 7 from the sealing portion 8 near the periphery can be suppressed.

The sealing portion 8 is made of a material containing thermoplastic resin. The sealing portion 8 is made of a material containing thermoplastic resin as a main component. The sealing part 8 may be made of 100% thermoplastic resin. Alternatively, the sealing portion 8 may be formed of a material containing a thermoplastic resin and an additive. If the sealing part 8 contains thermoplastic resin as a main component, the sealing part 8 can be joined to the photoelectric conversion substrate 2 and the moisture-proof cover 7 by heating.

Here, for example, if the sealing part 8 contains an ultraviolet curing resin as a main component, it is necessary to irradiate the sealing part 8 with ultraviolet rays when joining the photoelectric conversion substrate 2 and the moisture-proof cover 7. . However, since the moisture-proof cover 7 contains metal or the like, it cannot transmit ultraviolet rays. Further, if the moisture-proof cover 7 is one that transmits ultraviolet rays, there is a possibility that the scintillator layer 5 will be discolored by the ultraviolet rays, and the light (fluorescence) generated in the scintillator layer 5 will be absorbed by the scintillator layer 5.

On the other hand, since the sealing part 8 contains thermoplastic resin, it can be easily joined by heating. Furthermore, the scintillator layer 5 will not be discolored by ultraviolet rays. Further, since the time required for heating and cooling the sealing portion 8 is short, it is possible to shorten the manufacturing time and, by extension, to reduce the manufacturing cost.

As the thermoplastic resin, nylon, PET (polyethyleneterephthalate), polyurethane, polyester, polyvinyl chloride, ABS (acrylonitrile butadiene styrene), acrylic, polystyrene, polyethylene, polypropylene, etc. can be used. In this case, the water vapor permeability of polyethylene is 0.068 g·mm/day·m ² , and the water vapor permeability of polypropylene is 0.04 g·mm/day·m ² . These have low water vapor transmission rates. Therefore, if the sealing part 8 contains at least one of polyethylene and polypropylene as a main component, the amount of water that passes through the sealing part 8 and reaches the scintillator layer 5 can be significantly reduced.
The rigidity of the thermoplastic resin can be lower than the rigidity of the moisture-proof cover 7.

Moreover, the sealing part 8 can further include a filler using an inorganic material. If the sealing portion 8 contains a filler made of an inorganic material, the permeation of moisture can be further suppressed. As the inorganic material, talc, graphite, mica, kaolin (clay whose main component is kaolinite), etc. can be used. The filler may have a flat shape, for example. Since the moisture that has entered the interior of the sealing section 8 from the outside is prevented from diffusing by the filler made of an inorganic material, the speed at which the moisture passes through the sealing section 8 can be reduced. Therefore, the amount of moisture reaching the scintillator layer 5 can be reduced.

Here, the X-ray detector 1 that has been stored in a high temperature and high humidity environment may be used in a lower temperature environment. In such a case, water vapor inside the housing may condense and adhere to the surface of the X-ray detector 1. If there are minute cracks in the outer surface 8a of the sealing portion 8, there is a possibility that moisture adhering to the surface may enter the cracks and be guided into the interior of the sealing portion 8. Furthermore, when the X-ray detector 1 is transported to an environment below freezing, moisture that has entered the cracks may freeze. When the moisture that has entered the crack freezes, its volume increases, and as the crack becomes larger, it becomes easier for moisture to enter. If the above is repeated, there is a risk that the sealing part 8 will be damaged, the moisture-proof cover 7 will peel off from the sealing part 8, the sealing part 8 will peel off from the photoelectric conversion substrate 2, etc.

Therefore, it is preferable that at least the outer surface 8a of the sealing part 8 has water repellency. If at least the outer surface 8a of the sealing part 8 has water repellency, even if there is a crack in the outer surface 8a of the sealing part 8, it is possible to suppress moisture from entering the crack.
For example, a water repellent agent can be applied to the outer surface 8a of the sealing part 8. Moreover, if the sealing part 8 contains at least either polyethylene or polypropylene as a main component, it is possible to obtain the outer surface 8a having water repellency.

Further, immediately after applying the thermoplastic resin to the frame shape, it is preferable to observe the inside to check for bubbles, foreign matter, leak paths, etc. If such a check can be performed visually or using an optical microscope, production efficiency can be improved. Therefore, it is preferable that the thermoplastic resin applied in a frame shape is transparent even in the thickest part. That is, it is preferable that the sealing part 8 has translucency. In this way, it is possible to easily remove products that have bubbles, foreign matter, leak paths, etc. in the sealing part 8 and that may shorten the product life. Therefore, the quality of the product can be improved.

The support substrate 12 faces the first main surface M1 of the base material 2a. The support substrate 12 supports the photoelectric conversion substrate 2 (X-ray detection panel PNL). The support substrate 12 forms a space SP between it and the first main surface M1 of the base material 2a. The X-ray detector 1 further includes an adhesive 3. The adhesive 3 is located between the first main surface M1 of the base material 2a and the support substrate 12, and bonds the base material 2a and the support substrate 12 together.

The adhesive material 3 is located outside the scintillator layer 5 in plan view. The adhesive material 3 has a frame-like shape and extends continuously around the scintillator layer 5 . In this embodiment, the adhesive 3 is located in the second non-detection area NDA2. However, the adhesive material 3 only needs to be located outside the scintillator layer 5, and may be located in the first non-detection area NDA1. The material forming the adhesive 3 is not particularly limited. For example, the material forming the sealing portion 8 described above can be used as the material forming the adhesive 3.

In this embodiment, the space SP between the first main surface M1 of the base material 2a and the support substrate 12 is a space whose pressure is reduced from atmospheric pressure. The support substrate 12 and the base material 2a hold the space SP together with the adhesive 3.

Even when the X-ray detector 1 is transported by an airplane or the like, and even when the X-ray detector 1 is used at a high altitude, the space SP in a depressurized state can be maintained well. Note that if the space SP contains gas such as air, the gas may expand and cause damage to the X-ray detector 1, such as peeling off of the base material 2a from the support substrate 12.

Moreover, the space SP in a reduced pressure state can significantly reduce the amount of moisture that may exist in the space SP, compared to a space at atmospheric pressure where air exists. Alternatively, moisture can be prevented from existing in the space SP. Therefore, even if the base material 2a has moisture permeability, the amount of moisture that infiltrates the base material 2a from the first main surface M1 and heads toward the scintillator layer 5 and the light reflective layer 6 can be reduced. Alternatively, it is possible to prevent moisture from entering the scintillator layer 5 and the light reflecting layer 6.

Note that the X-ray detector 1 that has been stored in a high temperature and high humidity environment may be used in a lower temperature environment. However, in the space SP in a reduced pressure state, moisture does not adhere to the first main surface M1. Alternatively, even if the water vapor inside the space SP condenses, the amount of water adhering to the first main surface M1 is small. Therefore, even if the X-ray detector 1 is placed in a low temperature environment, the space SP can protect the scintillator layer 5 and the light reflection layer 6 from moisture.

The support substrate 12 has a third main surface M3 that faces the first main surface M1 of the base material 2a. While the base material 2a is a flexible substrate (or a flexible layer), the support substrate 12 is a rigid substrate. The elastic modulus of the support substrate 12 is higher than that of the base material 2a. Therefore, when the inside of the space SP is in a reduced pressure state, the base material 2a (photoelectric conversion substrate 2, X-ray detection panel PNL) is deformed, and the first main surface M1 of the base material 2a becomes the third main surface of the support substrate 12. It may also touch M3.

Both the first main surface M1 and the third main surface M3 are flat surfaces. Therefore, even if the first principal surface M1 contacts the third principal surface M3, it is possible to avoid a situation in which the X-ray detection panel PNL is distorted. At least in the detection area DA, the first main surface M1 is in contact with the third main surface M3. In this embodiment, the first main surface M1 is in contact with the third main surface M3 in the detection area DA and the first non-detection area NDA1. Since it is possible to avoid a situation in which the X-ray detection panel PNL is distorted or uneven at least in the detection area DA, X-rays (radiation) can be detected satisfactorily in the entire detection area DA.
The X-ray detector 1 is configured as described above.

According to the X-ray detector 1 according to the embodiment configured as described above, the X-ray detector 1 includes a photoelectric conversion substrate 2, a scintillator layer 5, and a support substrate 12. The photoelectric conversion substrate 2 has a flexible base material 2a. Therefore, compared to the case where the base material 2a is a rigid substrate made of glass or the like, it can contribute to making the photoelectric conversion substrate 2 lighter and thinner. Furthermore, since the base material 2a is more bendable than glass, it is possible to obtain a base material 2a that is strong against impact and hard to break.

The base material 2a is made of polyimide, which is a resin. Organic materials such as resins have moisture permeability. Since the base material 2a has moisture permeability, it is necessary to prevent moisture from entering the base material 2a in advance. This is because moisture deteriorates the characteristics of the light reflection layer 6 and the characteristics of the scintillator layer 5. For example, since the scintillator layer 5 has deliquescent properties, it is necessary to avoid a situation where it absorbs moisture and becomes liquefied.

Therefore, the atmosphere in contact with the first main surface M1 of the base material 2a is set to be an atmosphere reduced in pressure from atmospheric pressure. The amount of moisture that permeates into the base material 2a from the first main surface M1 can be reduced. Alternatively, it is possible to prevent moisture from entering the base material 2a from the first main surface M1. From the above, it is possible to obtain the X-ray detector 1 that can suppress moisture permeation to the scintillator layer 5. In other words, it is possible to obtain the X-ray detector 1 that can have high moisture-proof performance. As a result, it is possible to obtain an X-ray detector 1 that can extend the product life.

Since the base material 2a has flexibility, the X-ray detection panel PNL is a flexible panel. When the X-ray detection panel PNL is a flexible panel, it is difficult to fix the X-ray detection panel PNL inside the housing 51. Therefore, the X-ray detection panel PNL is supported by a support substrate 12 that is a rigid substrate. Thereby, the X-ray detection panel PNL can be easily fixed inside the housing 51 together with the support substrate 12.

Although one embodiment of the present invention has been described, the above embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment described above can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. The above-described embodiments and modifications thereof are included within the scope and gist of the invention, and are also included within the scope of the invention described in the claims and its equivalents.

For example, in the space SP, the amount of moisture present may be small. Alternatively, it is sufficient that no moisture exists in the space SP. Therefore, the space SP does not have to be a reduced pressure space. FIG. 6 is a plan view showing a part of the X-ray detector 1 according to a modification of the above embodiment.
As shown in FIG. 6, the space SP may be filled with dry gas. For example, by bonding the base material 2a and the support substrate 12 with the adhesive 3 in a dry gas atmosphere, a space SP filled with dry gas can be obtained.

Dry gas is a gas that does not contain moisture. Desirably, the drying gas is an inert gas including at least one of nitrogen, neon, argon, krypton, and xenon. Furthermore, the drying gas is not limited to an inert gas, and can be modified in various ways. For example, it is possible to use dry air as drying gas. In this modification, the first main surface M1 of the base material 2a is not in contact with the third main surface M3 of the support substrate 12, but may be in contact with the third main surface M3. Also in the modification described using FIG. 6, the scintillator layer 5 and the light reflection layer 6 can be protected from moisture, and the same effects as in the above embodiment can be obtained.

The internal space surrounded by the housing 51 and the entrance window 52 (the space to which the X-ray detection panel PNL is exposed) is an atmospheric pressure space where air exists. However, the space may be a space whose pressure is reduced from atmospheric pressure. Alternatively, the space may be filled with a dry gas such as an inert gas or dry air. Thereby, the scintillator layer 5 and the light reflection layer 6 can be further protected from moisture.

The technique described above is not limited to application to the X-ray detector 1, but can be applied to other X-ray detectors and various radiation detectors. The radiation detector may include a radiation detection panel that detects radiation instead of the X-ray detection panel PNL .
Below, the invention described in the original claims of the present application will be added.
[1] A flexible base material including a first main surface and a second main surface opposite to the first main surface, and a plurality of photoelectric cells located above the second main surface of the base material. a photoelectric conversion substrate having a conversion element;
a scintillator layer provided on the photoelectric conversion substrate and facing the second main surface and the plurality of photoelectric conversion elements;
a supporting substrate that faces the first main surface of the base material, supports the photoelectric conversion substrate, and has a higher elastic modulus than the elastic modulus of the base material,
The space between the base material and the support substrate is a space whose pressure is reduced from atmospheric pressure.
Radiation detector.
[2] A flexible base material including a first main surface and a second main surface opposite to the first main surface, and a plurality of photoelectric conversions located above the second main surface of the base material. a photoelectric conversion substrate having an element;
a scintillator layer provided on the photoelectric conversion substrate and facing the second main surface and the plurality of photoelectric conversion elements;
a support substrate that faces the first main surface of the base material and supports the photoelectric conversion substrate;
a dry gas filled in a space between the base material and the support substrate;
Radiation detector.
[3] The drying gas is an inert gas containing at least one of nitrogen, neon, argon, krypton, and xenon.
The radiation detector according to [2].
[4] Further comprising a frame-shaped adhesive material located between the first main surface of the base material and the support substrate, and bonding the base material and the support substrate,
The adhesive material holds the space together with the base material and the support substrate, and is located outside the scintillator layer in a plan view.
The radiation detector according to [1] or [2].
[5] Further comprising a light reflective layer provided on the scintillator layer,
The radiation detector according to [1] or [2].
[6] Further comprising a moisture-proof cover provided on the photoelectric conversion substrate, the scintillator layer, and the light reflection layer, and sealing the scintillator layer and the light reflection layer together with the photoelectric conversion substrate.
The radiation detector according to [5].
[7] The moisture-proof cover has flexibility,
The elastic modulus of the moisture-proof cover is lower than the elastic modulus of the supporting substrate.
The radiation detector according to [6].
[8] Further comprising a frame-shaped sealing part provided around the scintillator layer and joining the photoelectric conversion substrate and the moisture-proof cover,
The sealing portion seals the scintillator layer and the light reflection layer together with the photoelectric conversion substrate and the moisture-proof cover.
The radiation detector according to [6].

1...X-ray detector, 10...X-ray detection module, PNL...X-ray detection panel,
2... Photoelectric conversion substrate, 2a... Base material, 2b... Photoelectric conversion section, 2b1... Photoelectric conversion element,
2b2...TFT, 3...adhesive material, 51...casing, 52...incidence window, 5...scintillator layer,
5a...Side surface, 6...Light reflective layer, 7...Moisture-proof cover, 8...Sealing part, 11...Circuit board,
12... Support substrate, M1... First main surface, M2... Second main surface, M3... Third main surface, SP... Space,
DA...detection area, NDA1...first non-detection area, NDA2...second non-detection area.

Claims (7)

a flexible base material including a first main surface and a second main surface opposite to the first main surface; a plurality of photoelectric conversion elements located above the second main surface of the base material; A photoelectric conversion substrate having ,
a scintillator layer provided on the photoelectric conversion substrate and facing the second main surface and the plurality of photoelectric conversion elements;
a supporting substrate that faces the first main surface of the base material, supports the photoelectric conversion substrate, and has a higher elastic modulus than the elastic modulus of the base material ;
a frame-shaped adhesive located between the first main surface of the base material and the support substrate, and bonding the base material and the support substrate;
The space between the base material and the support substrate is a space whose pressure is reduced from atmospheric pressure,
The adhesive material holds the space together with the base material and the support substrate, and is located outside the scintillator layer in a plan view.
Radiation detector. a flexible base material including a first main surface and a second main surface opposite to the first main surface; a plurality of photoelectric conversion elements located above the second main surface of the base material; A photoelectric conversion board having
a scintillator layer provided on the photoelectric conversion substrate and facing the second main surface and the plurality of photoelectric conversion elements;
a support substrate that faces the first main surface of the base material and supports the photoelectric conversion substrate;
a dry gas filled in a space between the base material and the support substrate ;
a frame-shaped adhesive located between the first main surface of the base material and the support substrate, and bonding the base material and the support substrate;
The adhesive material holds the space together with the base material and the support substrate, and is located outside the scintillator layer in a plan view.
Radiation detector. The drying gas is an inert gas containing at least one of nitrogen, neon, argon, krypton, and xenon.
The radiation detector according to claim 2. further comprising a light reflective layer provided on the scintillator layer,
The radiation detector according to claim 1 or 2. Further comprising a moisture-proof cover provided on the photoelectric conversion substrate, the scintillator layer, and the light reflection layer, and sealing the scintillator layer and the light reflection layer together with the photoelectric conversion substrate.
The radiation detector according to claim 4 . The moisture-proof cover has flexibility,
The elastic modulus of the moisture-proof cover is lower than the elastic modulus of the supporting substrate.
The radiation detector according to claim 5 . further comprising a frame-shaped sealing part provided around the scintillator layer and joining the photoelectric conversion substrate and the moisture-proof cover,
The sealing portion seals the scintillator layer and the light reflection layer together with the photoelectric conversion substrate and the moisture-proof cover.
The radiation detector according to claim 5 .

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