JP2021189101A - Radiation detection module and radiation detector - Google Patents

Abstract

To provide a radiation detection module and a radiation detector capable of narrowing a frame or to provide the radiation detection module and the radiation detector, which have the high manufacturing yield.SOLUTION: A radiation detection module includes: a photoelectric conversion substrate 2; a scintillator layer 5; a frame-shaped sealing part 8; and a moisture-proof cover 7. The sealing portion 8 is formed of a material containing a thermoplastic resin and located separated from the scintillator layer 5. The moisture-proof cover 7 covers the scintillator layer 5 and is bonded to the outer surface 8a of the sealing portion 8.SELECTED DRAWING: Figure 6

Description

Embodiments of the present invention relate to a radiation detector including a radiation detection module and a radiation detection panel.

As a radiation detector, for example, an X-ray detector (X-ray plane detector) is known. The X-ray detection module of the X-ray detector includes a scintillator layer that converts X-rays into fluorescence and a photoelectric conversion substrate that converts fluorescence into electrical signals. The scintillator layer contains, for example, cesium iodide (CsI). Further, in order to increase the utilization efficiency of fluorescence and improve the 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, it is necessary to separate the scintillator layer and the light reflecting layer from the outside 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 peripheral edge of the moisture-proof cover is adhered to a photoelectric conversion substrate.

Japanese Unexamined Patent Publication No. 2017-44564 JP-A-2018-179514

The present embodiment provides a radiation detection module capable of narrowing the frame and a radiation detector including the radiation detection module. Alternatively, a radiation detector equipped with a radiation detection module having a high manufacturing yield and a radiation detection module is provided.

The radiation detection module according to one embodiment is
A frame-shaped seal formed of a photoelectric conversion substrate, a scintillator layer provided on the photoelectric conversion substrate, and a material containing a thermoplastic resin, provided around the scintillator layer, and bonded to the photoelectric conversion substrate. It comprises a stop and a moisture-proof cover that covers the scintillator layer and is joined to the outer surface of the sealing portion, the sealing portion being located away from the scintillator layer.

Further, the radiation detector according to the embodiment is
A radiation detection module and a circuit board electrically connected to the radiation detection module are provided, and the radiation detection module includes a photoelectric conversion board, a scintillator layer provided on the photoelectric conversion board, and thermoplasticity. A frame-shaped sealing portion formed of a material containing a resin and provided around the scintillator layer and bonded to the photoelectric conversion substrate, and a moisture-proof seal portion covering the scintillator layer and bonded to the outer surface of the sealing portion. With a cover, the encapsulation is located away from the scintillator layer.

FIG. 1 is a cross-sectional view showing an X-ray detector according to an embodiment. FIG. 2 is a perspective view showing a support board of the X-ray detector, an X-ray detection panel, a circuit board, and a plurality of FPCs. FIG. 3 is an enlarged cross-sectional view showing a part of the X-ray detection module of the X-ray detector. FIG. 4 is a circuit diagram showing the X-ray detection panel, a circuit board, and a plurality of FPCs. FIG. 5 is a plan view showing the X-ray detection module. FIG. 6 is a cross-sectional view showing the X-ray detection module along the line VI-VI. FIG. 7 is a cross-sectional view showing an X-ray detection module according to a modified example of the above embodiment. FIG. 8 is a plan view showing an X-ray detection module according to a comparative example. FIG. 9 is a cross-sectional view showing the X-ray detection module according to the comparative example along the line IX-IX.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. It should be noted that the disclosure is merely an example, and those skilled in the art can easily conceive of appropriate changes while maintaining the gist of the invention, which are naturally included in the scope of the present invention. Further, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc. of each part as compared with the actual embodiment, but this is just an example, and the interpretation of the present invention is used. It is not limited. Further, in the present specification and each figure, the same elements as those described above with respect to the above-mentioned figures may be designated by the same reference numerals, and detailed description thereof may be omitted as appropriate.

FIG. 1 is a cross-sectional view showing an X-ray detector 1 according to the present embodiment. The X-ray detector 1 is an X-ray image detector, and is an X-ray plane 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, and an incident. It is equipped with a window 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 incident window 52.

The incident window 52 is attached to the opening of the housing 51. The incident window 52 transmits X-rays. Therefore, X-rays pass through the incident window 52 and are incident on the X-ray detection module 10. The incident window 52 is formed in a plate shape and has a function of protecting the inside of the housing 51. The incident window 52 is preferably formed thinly with a material having a low X-ray absorption rate. This makes it possible to reduce the scattering of X-rays and the attenuation of the X-ray dose that occur in the incident window 52. Then, a thin and light X-ray detector 1 can be realized.
The X-ray detection module 10, the support board 12, the circuit board 11, the FPC2e1, and the like are housed inside the space surrounded by the housing 51 and the incident window 52.

Since the X-ray detection module 10 is configured 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 one flat surface of the support substrate 12 via an adhesive sheet. The support substrate 12 is formed of, for example, an aluminum alloy in a plate shape, and has the strength required to stably hold the X-ray detection panel PNL. This makes it possible to suppress damage to the X-ray detection panel PNL when vibration or impact is applied to the X-ray detector 1 from the outside.

The circuit board 11 is fixed to the other surface of the support board 12 via the spacers 9a and 9b. By using the spacers 9a and 9b, it is possible to maintain the electrical insulation distance from the support substrate 12 mainly composed of metal to the circuit board 11.
A circuit board 11 is fixed to the inner surface of the housing 51 via spacers 9c and 9d. By using the spacers 9c and 9d, it is possible to maintain the electrical insulation distance from the housing 51 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 the spacers 9a, 9b, 9c, and 9d.

A connector corresponding to the FPC2e1 is mounted on the circuit board 11, and the FPC2e1 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 FPC2e1 and the X-ray detection panel PNL. By this method, the electrical connection between the plurality of fine pads of the X-ray detection panel PNL and the plurality of fine pads of the FPC2e1 is secured. The pad of the X-ray detection panel PNL will be described later.

As described above, the circuit board 11 is electrically connected to the X-ray detection panel PNL via the connector, FPC2e1 and the like. The circuit board 11 electrically drives the X-ray detection panel PNL and electrically processes the output signal from the X-ray detection panel PNL.

FIG. 2 is a perspective view showing a support substrate 12, an X-ray detection panel PNL, a circuit board 11, and a plurality of FPC2e1 and 2e2 of the X-ray detector 1 of the present embodiment. Note that FIG. 2 does not show all the members of the X-ray detector 1. Illustration of some members of the X-ray detector 1, such as a sealing portion described later, is 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 has a substrate 2a, a photoelectric conversion unit 2b, a plurality of control lines (or gate lines) 2c1, a plurality of data lines (or signal lines) 2c2, and the like. The number, arrangement, and the like of the photoelectric conversion unit 2b, the control line 2c1, and the data line 2c2 are not limited to the example of FIG.

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 the plurality of control lines 2c1, and are arranged at predetermined intervals in the row direction.

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

Each photoelectric conversion unit 2b has a photoelectric conversion element 2b1 and a TFT (thin film transistor) 2b2 as a switching element. The TFT 2b2 is connected to a corresponding control line 2c1 and a 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 FPC2e1. The circuit board 11 gives a control signal S1 to a plurality of control lines 2c1 via the FPC2e1. The data line 2c2 is electrically connected to the circuit board 11 via the FPC2e2. 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 FPC2e2.

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

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

The TFT 2b2 has a gate electrode GE, a semiconductor layer SC, a source electrode SE, and a drain electrode DE. The photoelectric conversion element 2b1 is composed of a photodiode. The photoelectric conversion element 2b1 may be configured to convert light into electric charges.

The substrate 2a has a plate-like shape and is made of an insulating material. Examples of the insulating material include glass such as non-alkali glass. The planar shape of the substrate 2a is, for example, a quadrangle. The thickness of the substrate 2a is, for example, 0.7 mm. The insulating layer 21 is provided on the substrate 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, the source electrode SE, the drain electrode DE, the control line 2c1 and the data line 2c2 are formed by using a low resistance metal such as aluminum or chromium.

The source electrode SE is electrically connected to the source region of the semiconductor layer SC. 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, passes through a contact hole formed in the insulating layer 24, and is connected to the photoelectric conversion element 2b1. The insulating layer 25 is provided on the insulating layer 24 and the bias wire BL.

The insulating layers 21, 22, 23, 24, 25 are formed of an insulating material such as an inorganic insulating material or an organic insulating material. Examples of the inorganic insulating material include an oxide insulating material, a nitride insulating material, and an oxynitride insulating material. Examples of the organic insulating material include resin.

The scintillator layer 5 is provided on the photoelectric conversion substrate 2 (plurality of photoelectric conversion units 2b). The scintillator layer 5 is located at least in the detection region DA and covers the upper part of the plurality of photoelectric conversion units 2b. The scintillator layer 5 is configured to convert incident X-rays into light (fluorescence).

The photoelectric conversion element 2b1 converts the light incident from the scintillator layer 5 into electric charges. The converted charge is stored in the photoelectric conversion element 2b1. The TFT 2b2 can switch between storing electricity in the photoelectric conversion element 2b1 and discharging from the photoelectric conversion element 2b1. If the self-capacity of the photoelectric conversion element 2b1 is insufficient, the photoelectric conversion substrate 2 may further have 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). When the scintillator layer 5 is formed by the vacuum vapor deposition method, the scintillator layer 5 composed of an aggregate of a plurality of columnar crystals can be obtained. The thickness of the scintillator layer 5 is, for example, 600 μm. On the outermost surface of the scintillator layer 5, the thickness of the columnar crystals of the scintillator layer 5 is 8 to 12 μm.

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

When the scintillator layer 5 is formed by the vacuum vapor deposition method, a mask having an opening is used. In this case, the scintillator layer 5 is formed in the region facing the opening on the photoelectric conversion substrate 2. The scintillator material produced by vapor deposition also deposits on the surface of the mask. Then, the scintillator material is also deposited in the vicinity of the opening of the mask, and crystals grow so as to gradually project inside the opening. When crystals project from the mask into the opening, the deposition of the scintillator material on the photoelectric conversion substrate 2 is suppressed in the vicinity of the opening. Therefore, as shown in FIG. 2, the thickness of the vicinity of the peripheral edge of the scintillator layer 5 gradually decreases toward the outside.

Alternatively, the scintillator layers 5 may be arranged in a matrix and provided on the photoelectric conversion unit 2b on a one-to-one basis, and may have a plurality of scintillator units each having a square columnar shape. When forming such a scintillator layer 5, _{a scintillator material obtained by mixing gadolinium acid sulfide (Gd 2} O ₂ S) phosphor particles with a binder material is applied onto the photoelectric conversion substrate 2, and the scintillator material is fired and cured. Let me. After that, dicing with a dicer is performed to form a grid-like groove in the scintillator material. In the above case, an inert gas such as _{air or nitrogen (N 2} ) for antioxidant is sealed between the plurality of scintillator portions. Alternatively, the space between the plurality of scintillator units may be set to a space decompressed from the atmospheric pressure.

In the present embodiment, the X-ray detection panel PNL further includes a light reflecting layer 6. The light reflecting layer 6 is provided on the incident side of the scintillator layer 5 on the X-ray. The light reflection layer 6 is located at least in the detection region DA and covers the upper surface of the scintillator layer 5. The light reflection layer 6 is provided in order to improve the utilization efficiency of light (fluorescence) and improve the sensitivity characteristics. That is, the light reflecting layer 6 reflects the light generated in the scintillator layer 5 toward the side opposite to the side where the photoelectric conversion unit 2b is provided, and directs the light toward the photoelectric conversion unit 2b. However, the light reflecting layer 6 is not always necessary, and may be provided according to the sensitivity characteristics required for the X-ray detection module 10.

For example, a coating material obtained by mixing light-scattering particles made of titanium oxide (TiO ₂ ), a resin, and a solvent is applied onto the scintillator layer 5, and then the coating material is dried to form a light-reflecting layer 6. Can be formed.

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 variously modified. For example, the light reflecting layer 6 may be formed by forming a layer made of a metal having a high light reflectance such as a silver alloy or aluminum on the scintillator layer 5. Alternatively, the light reflecting layer 6 may be formed by providing a sheet containing a metal layer having a high light reflectance such as a silver alloy or aluminum on the surface thereof, a resin sheet containing light scattering particles, or the like on the scintillator layer 5. good.

When the paste-like coating material is applied onto the scintillator layer 5 and the coating material is dried, the coating material shrinks as the coating material dries, so that tensile stress is applied to the scintillator layer 5 and the scintillator layer 5 is photoelectric. It may peel off from the conversion substrate 2. Therefore, it is preferable to provide the sheet-shaped light reflecting layer 6 on the scintillator layer 5. In this case, the light reflecting layer 6 can be bonded onto the scintillator layer 5 by using, for example, double-sided tape, but it is preferable to place the light reflecting layer 6 on the scintillator layer 5. If the sheet-shaped light reflecting layer 6 is placed 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 reflecting layer 6 can be easily suppressed.

The moisture-proof cover (moisture-proof portion) 7 covers the scintillator layer 5 and the light-reflecting layer 6. The moisture-proof cover 7 is provided to prevent the characteristics of the light reflecting layer 6 and the characteristics of the scintillator layer 5 from deteriorating due to the moisture contained in the air. The moisture-proof cover 7 completely covers the exposed portion of the scintillator layer 5. The moisture-proof cover 7 may have a gap between it and the light-reflecting layer 6 and the like, and the moisture-proof cover 7 may come into contact with the light-reflecting layer 6 and the like.

The moisture-proof cover 7 is made of a sheet containing metal. Examples of the metal include a metal containing aluminum, a metal containing copper, a metal containing magnesium, a metal 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 and the like. The metal layer may contain, for example, the metal described above. The metal layer can be formed by using a sputtering method, a laminating method, or the like.

In this case, it is preferable to provide the metal layer on the scintillator layer 5 side rather than the resin layer. Since the metal layer can be covered with the resin layer, damage that can be received by the metal layer due to an external force or the like can be suppressed. Further, if the metal layer is provided on the scintillator layer 5 side with respect to 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 containing 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 the 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 and the like. The inorganic insulating layer can be formed by using a sputtering method or the like.

When the moisture-proof cover 7 is formed of a laminated sheet containing a metal layer, for example, the thickness of the resin layer can be substantially the same as the thickness of the metal layer. If the moisture-proof cover 7 contains 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. .. In general, the coefficient of linear expansion of the resin is larger than the coefficient of linear expansion of the metal. Therefore, if the thickness of the resin layer is made too large, the photoelectric conversion substrate 2 tends to warp. 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, and the like. In this case, the larger the thickness of the moisture-proof cover 7, the larger the amount of X-rays absorbed by the moisture-proof cover 7. On the other hand, the smaller the thickness of the moisture-proof cover 7, the lower the rigidity of the moisture-proof cover 7, and the more easily the moisture-proof cover 7 is 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 becomes too low, and pinholes may occur in the moisture-proof cover 7 due to damage caused by external force or the like, which may cause a leak. If 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 the unevenness of the upper end of the scintillator layer 5 deteriorates. Therefore, it may be difficult to confirm the above-mentioned gap and leak path. Further, the photoelectric conversion board 2 may be easily warped.

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, for example, an aluminum foil having a thickness of 10 to 50 μm. When the thickness of the aluminum foil is 10 to 50 μm, the amount of X-ray transmission can be increased by about 20 to 30% as compared with the aluminum foil having a thickness of 100 μm. Further, if the aluminum foil having a thickness of 10 to 50 μm is used, the occurrence of the above-mentioned leak can be suppressed, and the above-mentioned gap and leak path can be easily confirmed. Further, the warp of the photoelectric conversion board 2 can be suppressed.

In order to reduce the thermal expansion and contraction of the metal, it is desirable that the thickness of the metal such as aluminum is 30 μm or less. Then, it is desirable that the moisture-proof cover 7 contains an aluminum foil of 10 to 30 μm.

Here, since a large amount of X-ray irradiation to the human body has an adverse effect on health, the amount of X-ray irradiation to the human body can be suppressed to the minimum necessary. Therefore, in the case of the X-ray detector 1 used for medical treatment, the intensity of the irradiated X-rays may be low, and the intensity of the X-rays transmitted through the moisture-proof cover 7 may be very low. Since the moisture-proof cover 7 according to the present embodiment 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-ray is low.

FIG. 4 is a circuit diagram showing an X-ray detection panel PNL, a circuit board 11, and a plurality of FPC2e1 and 2e2.
As shown in FIGS. 2 to 4, the circuit board 11 is provided with a read circuit 11a and a signal detection circuit 11b. It should be noted that these circuits can be provided on one board, or these circuits can be provided separately on a plurality of boards. The other ends of the plurality of wirings provided in the FPC2e1 are electrically connected to the readout circuit 11a, respectively. The other ends of the plurality of wires provided in the FPC2e2 are electrically connected to the signal detection circuit 11b, respectively.

The readout circuit 11a switches between an on state and an off state of the TFT 2b2. The read circuit 11a has a plurality of gate drivers 11aa and a row selection circuit 11ab. A control signal S1 is input to the row selection circuit 11ab from an image processing unit (not shown) provided outside the X-ray detector 1. The row selection circuit 11ab inputs the control signal S1 to the corresponding gate driver 11aa according to the scanning direction of the X-ray image. The gate driver 11aa inputs the control signal S1 to the corresponding control line 2c1.

For example, the read circuit 11a sequentially inputs the control signal S1 to the plurality of control lines 2c1 via the FPC2e1. The TFT 2b2 is turned on or off by the control signal S1 input to the control line 2c1, and the TFT 2b2 is turned on, so that the electric charge (image data signal S2) from the photoelectric conversion element 2b1 is output to the FPC 2e2.

The signal detection circuit 11b has a plurality of integrating amplifiers 11ba, a plurality of selection circuits 11bb, and a plurality of AD converters 11bc. One integrator amplifier 11ba is electrically connected to one data line 2c2. The integration amplifier 11ba sequentially receives the image data signals S2 from the plurality of photoelectric conversion units 2b. Then, the integration amplifier 11ba integrates the current flowing within a fixed time and outputs the voltage corresponding to the integrated value to the selection circuit 11bb. By doing so, it is possible to convert the value (charge amount) of the current flowing through the data line 2c2 into a voltage value within a predetermined time. That is, the integrator amplifier 11ba converts the image data information corresponding to the intensity distribution of the fluorescence generated in the scintillator layer 5 into the potential information.

The selection circuit 11bb selects the integration amplifier 11ba to be read out, and sequentially reads out the image data signal S2 converted into the potential information. The AD converter 11bc sequentially converts the read image data signal S2 into a digital signal. The image data signal S2 converted into a digital signal is input to the image processing unit via wiring. The image data signal S2 converted into a digital signal may be wirelessly transmitted to the image processing unit. The image processing unit constitutes an X-ray image based on the image data signal S2 converted into a digital signal. The image processing unit can also be integrated with the circuit board 11.

FIG. 5 is a plan view showing the X-ray detection module 10. In FIG. 5, the scintillator layer 5 is provided with an upward-sloping diagonal line, and the sealing portion 8 is provided with a downward-sloping diagonal line. FIG. 6 is a cross-sectional view showing the X-ray detection module 10 along the line VI-VI.
As shown in FIGS. 5 and 6, the photoelectric conversion substrate 2 has a detection region DA, a frame-shaped first non-detection region NDA1 located around the detection region DA, and a first non-detection region NDA1 outside the first non-detection region NDA1. It has 2 non-detection regions NDA2 and. In the present embodiment, the second non-detection region NDA2 has a frame-like shape.

The scintillator layer 5 is located at least in the detection region DA. The photoelectric conversion substrate 2 further has a plurality of pads 2d1 and a plurality of pads 2d2. Pads 2d1 and 2d2 are located in the second non-detection region NDA2. In the present embodiment, the plurality of pads 2d1 are arranged along the left side of the substrate 2a, and the plurality of pads 2d2 are arranged along the lower side of the substrate 2a. Note that FIG. 5 schematically shows a plurality of pads, and the number, shape, size, position, and pitch of the plurality of pads are not limited to the example shown in FIG.

One control line 2c1 extends a detection region DA, a first non-detection region NDA1, and a second non-detection region NDA2 and is electrically connected to one of a plurality of pads 2d1. One data line 2c2 extends a detection region DA, a first non-detection region NDA1, and a second non-detection region NDA2 and is electrically connected to one of a plurality of pads 2d2.
One of the plurality of wires provided in the FPC2e1 is electrically connected to one pad 2d1, and one of the plurality of wires provided in the FPC2e2 is electrically connected to the one pad 2d2. (Fig. 2).

The X-ray detection module 10 further includes a sealing portion 8. The sealing portion 8 is provided around the scintillator layer 5. The sealing portion 8 has a frame-like shape and continuously extends around the scintillator layer 5. The sealing portion 8 is bonded to the photoelectric conversion substrate 2 (for example, the insulating layer 25).

The moisture-proof cover 7 completely covers the scintillator layer 5 in the plan view shown in FIG. As shown in FIG. 6, the portion of the scintillator layer 5 that is not covered by the photoelectric conversion substrate 2 and the sealing portion 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 portion 8. The moisture-proof cover 7 covers at least a part of the sealing portion 8. It is advantageous to completely cover the sealing portion 8 with the moisture-proof cover 7 because the moisture permeability path becomes smaller. For example, if the moisture-proof cover 7 and the sealing portion 8 are joined in an environment where the pressure is lower than the atmospheric pressure, the moisture-proof cover 7 can be brought into contact with the light reflecting layer 6 or the like. Further, in general, the scintillator layer 5 has voids of about 10 to 40% of its volume. Therefore, if the void contains gas, the gas may expand and the moisture-proof cover 7 may be damaged when the X-ray detector 1 is transported by an aircraft or the like. If the moisture-proof cover 7 and the sealing portion 8 are joined in an environment where the pressure is lower than the atmospheric pressure, damage to the moisture-proof cover 7 can be suppressed even when the X-ray detector 1 is transported by an aircraft or the like. can. From the above, it is preferable that the pressure in the space defined by the sealing portion 8 and the moisture-proof cover 7 is lower than the atmospheric pressure.

If the thickness of the moisture-proof cover 7 is reduced, the rigidity of the moisture-proof cover 7 decreases. Therefore, when the moisture-proof cover 7 is provided with a brim or the like to form a three-dimensional moisture-proof cover 7, for example, when a metal foil is press-molded, cracks or the like are likely to occur. On the other hand, the vicinity of the peripheral edge of the moisture-proof cover 7 having a sheet shape is joined to the outer surface 8a of the sealing portion 8. Therefore, it is not necessary to process the moisture-proof cover 7 into a three-dimensional shape in advance, and the moisture-proof cover 7 having a sheet shape 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, it is possible to suppress the occurrence of defects such as cracks in the moisture-proof cover 7. Further, it is possible to suppress the warp of the photoelectric conversion board 2 and the deformation of the photoelectric conversion board 2 due to heat.

Further, as will be described later, by heating the vicinity of the peripheral edge of the moisture-proof cover 7, the vicinity of the peripheral edge of the moisture-proof cover 7 and the sealing portion 8 are joined. In this case, when the temperature near the peripheral edge of the moisture-proof cover 7 and the temperature of the sealing portion 8 decrease, thermal stress is generated between the vicinity of the peripheral edge of the moisture-proof cover 7 and the sealing portion 8. If thermal stress is generated between the vicinity of the peripheral edge of the moisture-proof cover 7 and the sealing portion 8, peeling may occur between the vicinity of the peripheral edge of the moisture-proof cover 7 and the sealing portion 8. If peeling occurs, the moisture-proof performance may be significantly reduced. Since the thickness of the moisture-proof cover 7 is 10 μm or more and 50 μm or less, the moisture-proof cover 7 can be easily extended when thermal stress is generated. Therefore, since the thermal stress can be relaxed, peeling of the vicinity of the peripheral edge of the moisture-proof cover 7 from the sealing portion 8 can be suppressed.

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

Here, for example, if the sealing portion 8 contains an ultraviolet curable resin as a main component, it is necessary to irradiate the sealing portion 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 transmits ultraviolet rays, the scintillator layer 5 may be discolored by the ultraviolet rays, and the light (fluorescence) generated in the scintillator layer 5 may be absorbed by the scintillator layer 5.

On the other hand, since the sealing portion 8 contains a thermoplastic resin, it can be easily joined by heating. Further, the scintillator layer 5 is not discolored by ultraviolet rays. Further, since the time required for heating and cooling the sealing portion 8 can be shortened, the manufacturing time can be shortened and the manufacturing cost can be reduced.

As the thermoplastic resin, nylon, PET (Polyethyleneterephthalate), polyurethane, polyester, polyvinyl chloride, ABS (Acrylonitrile Butadiene Styrene), acrylic, polystyrene, polyethylene, polypropylene and the like 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 water vapor permeabilitys are low. Therefore, if the sealing portion 8 contains at least one of polyethylene and polypropylene as a main component, the water content that permeates the inside of the sealing portion 8 and reaches the scintillator layer 5 can be significantly reduced.
The rigidity of the thermoplastic resin can be made lower than the rigidity of the moisture-proof cover 7.

Further, the sealing portion 8 can further contain a filler using an inorganic material. If the sealing portion 8 contains a filler made of an inorganic material, the permeation of water can be further suppressed. As the inorganic material, talc, graphite, mica, kaolin (clay containing kaolinite as a main component) and the like can be used. The filler can have, for example, a flat morphology. Moisture that has entered the inside of the sealing portion 8 from the outside is prevented from diffusing by a filler made of an inorganic material, so that the speed at which the moisture passes through the sealing portion 8 can be reduced. Therefore, the amount of water that reaches the scintillator layer 5 can be reduced.

Here, the X-ray detector 1 stored in a hot and humid environment may be used in a lower temperature environment. In such a case, water vapor inside the housing is dewed. , May adhere to the surface of the X-ray detector 1. If there are fine cracks on the outer surface 8a of the sealing portion 8, the moisture adhering to the surface may invade the cracks and be guided to the inside of the sealing portion 8. In addition, the X-ray detector 1 may be transported to an environment below freezing point, and the water that has entered the crack may freeze. When the water that has invaded the crack freezes, the volume increases, so that the crack becomes larger and the water becomes easier to invade. If the above is repeated, the sealing portion 8 may be damaged, the moisture-proof cover 7 may be peeled off from the sealing portion 8, the sealing portion 8 may be peeled off from the photoelectric conversion substrate 2, and the like.

Therefore, it is preferable that at least the outer surface 8a of the sealing portion 8 has water repellency. If at least the outer surface 8a of the sealing portion 8 has water repellency, even if there is a crack in the outer surface 8a of the sealing portion 8, it is possible to suppress the invasion of water into the crack.
For example, a water repellent can be applied to the outer surface 8a of the sealing portion 8. Further, if the sealing portion 8 contains at least one of polyethylene and polypropylene as a main component, an outer surface 8a having water repellency can be obtained.

Immediately after applying the thermoplastic resin in a frame shape, it is preferable to observe the inside and check for the presence of bubbles, foreign substances, leak paths, and the like. If such a check can be performed visually or by using an optical microscope, the production efficiency can be improved. Therefore, it is preferable that the thermoplastic resin applied in a frame shape is transparent even in the portion having the largest thickness. That is, it is preferable that the sealing portion 8 has translucency. By doing so, it is possible to easily remove the product having bubbles, foreign substances, leak paths, etc. in the sealing portion 8 and which may shorten the product life. Therefore, the quality of the product can be improved.

The sealing portion 8 is located away from the scintillator layer 5. The sealing portion 8 is located in the first non-detection region NDA1. The sealing portion 8 is located between the scintillator layer 5 and the plurality of pads 2d1, 2d2 apart from the plurality of pads 2d1, 2d2. A material for forming the sealing portion 8 can be applied only on the cleaning portion of the photoelectric conversion substrate 2. The amount of wet spread of the material for forming the sealing portion 8 can be made constant over the entire circumference, and the sealing portion 8 having a uniform height T and width W can be obtained.

In addition, it can contribute to narrowing the frame of the X-ray detector 1. When the sealing portion 8 is brought into contact with the scintillator layer 5, the amount of wet spread of the sealing portion 8 becomes non-uniform, which leads to expansion of the frame area.

Further, the width of the sealing portion 8 may be smaller than that in the case where the sealing portion 8 is brought into contact with the scintillator layer 5. However, on the scintillator layer 5 and on the contaminated portion of the photoelectric conversion substrate 2 (the portion of the photoelectric conversion substrate 2 in the vicinity of the scintillator layer 5), the adhesion with the thermoplastic resin is originally small, which contributes to adhesion stability. It is considered that this is not the case, and there is substantially no decrease in the adhesive force of the sealing portion 8.

As described above, the sealing portion 8 made of a thermoplastic resin formed in a frame shape so as to surround the scintillator layer 5 is heat-coated and formed at a position separated from the scintillator layer 5 by a certain distance. The height T and width W can be made uniform, and even with the X-ray detector 1 with a narrow frame, stable adhesion of the moisture-proof cover 7 can be ensured, and the positions of the moisture-proof cover 7 and the sealing portion 8 can be secured. It is possible to obtain an X-ray detection module 10 for an X-ray detector 1 that realizes improved accuracy and has high moisture-proof performance.

The light reflecting layer 6 covers a part of the side surface 5a of the scintillator layer 5. However, the light reflecting layer 6 may cover the entire side surface 5a of the scintillator layer 5 or may not cover the side surface 5a of the scintillator layer 5 at all. It is desirable that the light reflecting layer 6 is not in contact with the upper surface of the photoelectric conversion substrate 2. Since the light reflecting layer 6 is present on the upper surface of the photoelectric conversion substrate 2, the material for forming the sealing portion 8 is repelled by the light reflecting layer 6, and the amount of wet spread of the material for forming the sealing portion 8 is reached. This is because can be non-uniform.

As described above, the sealing portion 8 is not in contact with the scintillator layer 5. Compared with the case where the sealing portion 8 is in contact with the scintillator layer 5, the amount of water that can permeate the inside of the sealing portion 8 and reach the scintillator layer 5 can be suppressed.

If the shape of the outer surface 8a of the sealing portion 8 is a curved surface protruding outward, it is easy to make the vicinity of the peripheral edge of the moisture-proof cover 7 follow the outer surface 8a of the sealing portion 8. Therefore, it becomes easy to bring the moisture-proof cover 7 into close contact with the sealing portion 8. Further, since the moisture-proof cover 7 can be gently deformed, it is possible to suppress the occurrence of defects such as cracks in the moisture-proof cover 7 even if the thickness of the moisture-proof cover 7 is reduced.

When the moisture-proof cover 7 is brought into close contact with the sealing portion 8, it is preferable that the peripheral end surface 7a of the moisture-proof cover 7 is located in the vicinity of the photoelectric conversion substrate 2 or is in contact with the photoelectric conversion substrate 2. By doing so, it is possible to effectively suppress the invasion of moisture and the like contained in the atmosphere into the inside of the sealing portion 8.

The height T of the sealing portion 8 is not particularly limited. The apex of the sealing portion 8 may be located on the same plane as the upper surface of the scintillator layer 5. Alternatively, the sealing portion 8 may protrude beyond the same plane as the upper surface of the scintillator layer 5, or may protrude toward the front of the same plane as the upper surface of the scintillator layer 5.
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 detection module 10 includes a photoelectric conversion substrate 2, a scintillator layer 5, a sealing portion 8, and a moisture-proof cover 7. It is equipped with. The sealing portion 8 is located at a certain distance from the scintillator layer 5. A sealing portion 8 is formed of the coated material on the surface of the photoelectric conversion substrate 2 where the cleanliness is maintained. The amount of wet spread of the material for forming the sealing portion 8 can be made constant over the entire circumference. This makes it possible to obtain an X-ray detector 1 provided with an X-ray detection module 10 and an X-ray detection module 10 capable of narrowing the frame. Then, it is possible to obtain an X-ray detector 1 provided with an X-ray detection module 10 and an X-ray detection module 10 having a high manufacturing yield.

Further, the shape of the sealing portion 8 can be easily controlled, sufficient adhesion of the moisture-proof cover 7 to the sealing portion 8 can be ensured, and the positional accuracy of the moisture-proof cover 7 and the sealing portion 8 can be determined. It is possible to obtain an X-ray detection module 10 that can be improved and has high moisture-proof performance.

Next, a modified example of the above embodiment will be described. FIG. 7 is a cross-sectional view showing the X-ray detection module 10 according to the modified example of the above embodiment.
As shown in FIG. 7, the moisture-proof cover 7 may bend between the scintillator layer 5 and the sealing portion 8. For example, when the space surrounded by the photoelectric conversion substrate 2, the scintillator layer 5, the sealing portion 8, and the moisture-proof cover 7 is a decompression space, the moisture-proof cover 7 can be formed by bending. If the vicinity of the peripheral edge of the moisture-proof cover 7 can be bent, the difference between the heat shrinkage amount of the moisture-proof cover 7 and the heat shrinkage amount of the photoelectric conversion substrate 2 can be absorbed. Therefore, deformation of the photoelectric conversion board 2 due to thermal stress can be suppressed.

Next, the X-ray detector 1 according to the comparative example will be described. FIG. 8 is a plan view showing the X-ray detection module 10 according to this comparative example. FIG. 9 is a cross-sectional view showing the X-ray detection module 10 according to this comparative example along the line IX-IX.
As shown in FIGS. 8 and 9, the moisture-proof cover 7 is an aluminum laminated film or a transparent moisture-proof film having a multilayer structure of an inorganic film and an organic material such as PET. The sealing portion 8 is bonded to the side surface 5a of the scintillator layer 5 and the photoelectric conversion substrate 2. The sealing portion 8 is formed by coating using a dispenser or the like.

However, the wet spread of the coating material differs from each other on the side surface 5a of the scintillator layer 5, the contaminated portion of the photoelectric conversion substrate 2, and the clean portion of the photoelectric conversion substrate 2 (the portion of the photoelectric conversion substrate 2 away from the scintillator layer 5). .. Foreign matter 100 may be present in the contaminated portion of the photoelectric conversion substrate 2. Therefore, it becomes difficult to control the shape of the sealing portion 8, and the height and width of the sealing portion 8 tend to be non-uniform. It becomes difficult to control the amount of the sealing portion 8 protruding from the moisture-proof cover 7 and to secure the stability of the adhesion of the moisture-proof cover 7 to the sealing portion 8, the reliability of the moisture-proof cover 7 deteriorates, and the sealing to the pad 2d1. It invites the protrusion of the part 8.

Although embodiments of the present invention have been described, the above embodiments are presented as examples and are not intended to limit the scope of the invention. The above-mentioned novel embodiment can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The above embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

For example, the above-mentioned technique is not limited to the application to the X-ray detection module 10 and the X-ray detector 1, but various radiation detection modules such as other X-ray detection modules, and other X-rays. It can be applied to various radiation detectors such as line detectors. The radiation detection module may include a radiation detection panel for detecting radiation instead of the X-ray detection panel PNL.

1 ... X-ray detector, 10 ... X-ray detection module, PNL ... X-ray detection panel,
2 ... photoelectric conversion board, 2a ... substrate, 2b ... photoelectric conversion unit, 2b1 ... photoelectric conversion element,
2b2 ... TFT, 2c1 ... control line, 2c2 ... data line,
2d1, 2d2 ... Pad, 5 ... Scintillator layer, 5a ... Side surface, 6 ... Light reflection layer,
7 ... Moisture-proof cover, 8 ... Sealing part, 8a ... Outer surface, 11 ... Circuit board, 12 ... Support board,
DA ... detection area, NDA1 ... first non-detection area, NDA2 ... second non-detection area.

Claims (6)

Photoelectric conversion board and
The scintillator layer provided on the photoelectric conversion board and
A frame-shaped sealing portion formed of a material containing a thermoplastic resin, provided around the scintillator layer, and bonded to the photoelectric conversion substrate, and a frame-shaped sealing portion.
A moisture-proof cover that covers the scintillator layer and is joined to the outer surface of the sealing portion is provided.
The sealing portion is located away from the scintillator layer.
Radiation detection module. The thermoplastic resin is at least one of polyethylene and polypropylene.
The radiation detection module according to claim 1. The moisture-proof cover is any one of 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. ,
The radiation detection module according to claim 1. The height and width of the sealing portion are uniform.
The radiation detection module according to claim 1. The photoelectric conversion board has a plurality of pads and has a plurality of pads.
The sealing portion is located between the scintillator layer and the plurality of pads apart from the plurality of pads.
The radiation detection module according to claim 1. The radiation detection module according to any one of claims 1 to 5.
A circuit board electrically connected to the radiation detection module.
Radiation detector.

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