WO2020100588A1

WO2020100588A1 - Radiation imaging device, method for manufacturing same, and radiation imaging system

Info

Publication number: WO2020100588A1
Application number: PCT/JP2019/042531
Authority: WO
Inventors: 知昭市村; 尚志郎猿田; 竹中　克郎
Original assignee: キヤノン株式会社
Priority date: 2018-11-14
Filing date: 2019-10-30
Publication date: 2020-05-22
Also published as: JP2020079767A

Abstract

Provided is a configuration for enhancing the mechanical strength of a radiation imaging device in which a scintillator is disposed in a recess formed in a substrate. This invention comprises: a sensor substrate 101 having a plurality of pixels for converting light into electrical signals provided on a first surface 102 positioned on a side upon which radiation 401 is incident, and a recess 104 provided on a second surface 103 positioned on the reverse side from the first surface 102; a scintillator 111 that is provided in the recess 104 and converts the radiation 401 into light; and a substrate 113 that is adhered to the second surface 103 of the sensor substrate 101 and the scintillator 111 via an adhesive layer 112.

Description

Radiation imaging apparatus and manufacturing method thereof, and radiation imaging system

The present invention relates to a radiation imaging apparatus, a method for manufacturing the same, and a radiation imaging system.

Radiation imaging devices that use flat panel detectors (FPDs) as radiation imaging panels are widely used in medical image diagnosis and non-destructive inspection. This radiation imaging apparatus is mainly classified into a direct conversion type that directly converts incident radiation into an electric signal and an indirect conversion type that converts the incident radiation into light with a scintillator and then converts this light into an electrical signal. can do. In a radiation imaging apparatus of indirect conversion type, it is advantageous to use a thallium-activated cesium iodide phosphor that forms needle crystals as a scintillator in order to obtain high spatial resolution. The method for forming the thallium-activated cesium iodide phosphor is an indirect-type formation method in which a moisture-proof protective treatment is formed on another support in advance, and an indirect type formation method is used in which it is directly deposited on the sensor substrate. A direct mold forming method is known. The direct mold forming method is advantageous in obtaining high spatial resolution.

For example, in Patent Document 1, a photoelectric conversion element is formed on the incident side of radiation, a recess is formed on the surface of the substrate opposite to the incident side to reduce the thickness of the substrate, and a scintillator is formed in this recess. Has proposed a technique for suppressing the absorption of radiation by the substrate to improve the sensitivity.

Japanese Patent No. 5604323

Specifically, in Patent Document 1, a scintillator is arranged in a recess formed on the surface of the housing substrate on the side opposite to the side on which radiation enters, and the scintillator is provided in the thick plate portion of the housing substrate to close the opening of the recess. On the other hand, there has been proposed a radiation image detecting device in which a supporting substrate or the like is adhered via an adhesive portion. However, in the radiation image detecting device described in Patent Document 1, since the mechanical strength of the device relating to this adhesion is insufficient, there is a risk of mechanical breakage when external stress is applied.

The present invention has been made in view of such problems, and an object thereof is to provide a mechanism for improving mechanical strength in a radiation imaging apparatus in which a scintillator is arranged in a recess formed in a substrate. To do.

In the radiation imaging apparatus of the present invention, a plurality of pixels for converting light into an electric signal are provided on the first surface located on the side where the radiation enters, and the first surface located on the side opposite to the first surface is provided. A sensor substrate having a concave portion on the second surface, a scintillator provided on the concave portion for converting the radiation into the light, and the second surface and the scintillator are bonded to each other via an adhesive layer. And a substrate.

The present invention also includes a method of manufacturing the above-described radiation imaging apparatus.

It is a figure which shows an example of schematic structure of the radiation imaging system containing the radiation imaging device which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of schematic structure in the radiation imaging panel of the radiation imaging device which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of schematic structure in the radiation imaging panel of the radiation imaging device which concerns on the 2nd Embodiment of this invention. It is a figure of the measurement result which shows the change of DQE by spatial frequency in the radiation imaging panel which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of a schematic structure in the radiation imaging panel of the radiation imaging device which concerns on the 3rd Embodiment of this invention. It is a figure which shows an example of the bone separation image obtained with the radiation imaging device which concerns on the 3rd Embodiment of this invention.

A mode (embodiment) for carrying out the present invention will be described below with reference to the drawings. At this time, in the following description and the drawings, common reference numerals are given to common configurations across a plurality of drawings. Therefore, common configurations will be described with reference to a plurality of drawings, and description of configurations with common reference numerals will be appropriately omitted. In addition, in the radiation in the present invention, in addition to α-rays, β-rays, γ-rays, etc., which are beams produced by particles (including photons) emitted by radiation decay, a beam having the same or higher energy, for example, X-rays. It may include rays, particle rays, cosmic rays, and the like.

(First embodiment)
First, a first embodiment of the present invention will be described.

FIG. 1 is a diagram showing an example of a schematic configuration of a radiation imaging system 10 including a radiation imaging apparatus 100 according to the first embodiment of the present invention. The radiation imaging system 10 is configured to electrically capture an optical image of the inspection target T formed by the radiation 401 and obtain an electrical radiation image (that is, radiation image data). Specifically, the radiation imaging system 10 includes a radiation imaging apparatus 100, a computer 200, an exposure control apparatus 300, and a radiation source 400, as shown in FIG.

The radiation source 400 starts irradiation of the radiation 401 according to the exposure command from the exposure control device 300. Radiation 401 emitted from the radiation source 400 passes through the inspection target T and enters the radiation imaging apparatus 100. Further, the radiation source 400 stops the irradiation of the radiation 401 according to the stop command from the exposure control device 300.

The radiation imaging apparatus 100 is an apparatus that captures a radiation image of the inspection target T using the radiation 401. As shown in FIG. 1, the radiation imaging apparatus 100 includes a radiation imaging panel 110, a control unit 120 for controlling the radiation imaging panel 110, and signal processing for processing a signal output from the radiation imaging panel 110. It is configured to have a portion 121. At this time, the example shown in FIG. 1 illustrates the case where the signal processing unit 121 is provided inside the control unit 120, but the present embodiment is not limited to this mode. For example, a mode in which the signal processing unit 121 is provided outside the control unit 120 as a separate configuration is also applicable to this embodiment.

The radiation imaging panel 110 generates an image signal according to the incident radiation 401 (including the radiation 401 transmitted through the inspection target T). Based on this image signal, the radiation image described above is acquired.

The control unit 120 controls the operation of the radiation imaging apparatus 100 and performs various types of processing. The control unit 120 includes, for example, a PLD (Programmable Logic Device) such as an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated), or a general-purpose computer in which all or a part of these programs are incorporated. It can be configured by a combination.

The signal processing unit 121 can, for example, perform A / D conversion on the image signal output from the radiation imaging panel 110, and output this to the computer 200 as radiation image data. Further, the signal processing unit 121 may generate a stop signal for stopping the irradiation of the radiation 401 from the radiation source 400, for example, based on the image signal output from the radiation imaging panel 110. In this case, the stop signal is supplied to the exposure control device 300 via the computer 200, and the exposure control device 300 sends a stop command to the radiation source 400 in response to the stop signal.

The computer 200 comprehensively controls the operation of the radiation imaging system 10 and performs various types of processing. The computer 200 can perform, for example, control of the radiation imaging apparatus 100 and the exposure control apparatus 300, and processing for receiving radiation image data from the radiation imaging apparatus 100 and displaying it as a radiation image. The computer 200 also has a function as an input unit for the user to input the imaging conditions of the radiographic image, for example.

The exposure control device 300 is configured to have an exposure switch. When the user turns on the exposure switch, the exposure control device 300 transmits an exposure command to the radiation source 400 and also transmits a start notification indicating the start of emission of the radiation 401 to the computer 200. The computer 200 that receives this start notification notifies the control unit 120 of the radiation imaging apparatus 100 of the start of irradiation of the radiation 401 in response to the start notification. In response to this notification, the control unit 120 of the radiation imaging apparatus 100 causes the radiation imaging panel 110 to generate an image signal according to the incident radiation 401.

FIG. 2 is a diagram showing an example of a schematic configuration of the radiation imaging panel 110 of the radiation imaging apparatus 100 according to the first embodiment of the present invention. Specifically, FIG. 2 shows a cross-sectional view of the radiation imaging panel 110 in the incident direction of the radiation 401 shown in FIG. In the following description, the radiation imaging panel 110 according to the first embodiment shown in FIG. 2 will be described as a “radiation imaging panel 110-1”. Further, in FIG. 2, for example, X-rays can be applied as the radiation 401 shown in FIG.

As shown in FIG. 2, the radiation imaging panel 110-1 is configured to include a sensor substrate 101, a scintillator 111, an adhesive layer 112, a reinforcing substrate 113, and a connection terminal portion 114. Further, in FIG. 2, in the sensor substrate 101, the first surface 102 located on the side where the radiation 401 enters and the second surface 103 located on the side opposite to the side where the radiation 401 enters are illustrated. ..

In the sensor substrate 101, the effective pixel region 105 and the dummy pixel region 106 are provided on the first surface 102, and the concave portion 104 is provided on the second surface 103 located on the side opposite to the first surface 102. It is the first substrate. In the effective pixel region 105, a plurality of pixels each including a photoelectric conversion element that generates an electric signal according to the light converted from the radiation 401 by the scintillator 111 are arranged in a two-dimensional array (for example, a matrix). There is. In this embodiment, for example, 3300 pixels × 2800 pixels are provided as the effective pixel region 105 and the dummy pixel region 106 on the sensor substrate 101 having a size of about 550 mm × 445 mm. Specifically, in the present embodiment, of the 3300 pixels × 2800 pixels, the area of 10 pixels arranged on the outer periphery is defined as the dummy pixel area 106, and the area of 3280 pixels × 2780 pixels arranged inside thereof is the effective pixel. It can be configured as the region 105. In the present embodiment, the number of pixels provided on the sensor substrate 101 and the number of pixels provided on the effective pixel region 105 can be appropriately set according to the size of the sensor substrate 101, the inspection target T, and the like.

Further, in the effective pixel region 105, column signal lines for further extracting electric signals generated in the respective pixels, row signal lines for driving respective elements included in the respective pixels in the effective pixel region 105, etc. Is provided. Further, these column signal lines and row signal lines can be electrically connected to the read circuit board and the drive circuit board via a flexible wiring board, respectively. Further, in the present embodiment, the connection terminal portion 114 is provided on the first surface 102 of the sensor substrate 101 in order to connect the column signal line and the row signal line to the read circuit substrate and the drive circuit substrate. Has been. In the present embodiment, the electrical signal generated in each pixel of the effective pixel area 105 is output from the radiation imaging panel 110 as an image signal via the connection terminal portion 114.

In the above-described example, an example in which the readout circuit board and the drive circuit board are arranged outside the radiation imaging panel 110 has been described. However, the readout circuit board and the drive circuit board are arranged as one configuration of the radiation imaging panel 110. It may be. Even in the case of this form, the sensor substrate 101 is provided with the connection terminal portion 114, and the electric signal generated in each pixel of the effective pixel region 105 is transmitted from the radiation imaging panel 110 via the connection terminal portion 114. Can be output. For example, in the present embodiment, the operation of the plurality of pixels including the effective pixel area 105 and the dummy pixel area 106 is performed by the control unit 120 illustrated in FIG. Further, for example, in the present embodiment, the electric signals output from the plurality of pixels including the effective pixel region 105 and the dummy pixel region 106 are processed by the signal processing unit 121 illustrated in FIG.

In the radiation imaging panel 110-1, as described above, the recess 104 is formed on the second surface 103 of the sensor substrate 101. In FIG. 2, as a specific portion forming the recess 104, a top 1041 of the recess, a side 1042 of the recess, and a bottom 1043 of the recess are illustrated. At this time, the top 1041 of the recess may be defined as “the top of the second surface 103 of the sensor substrate 101 excluding the recess 104”. In the example shown in FIG. 2, the radiation imaging panel 110-1 has the scintillator 111 formed on the bottom 1043 of the recess and the side 1042 of the recess so as to fill the recess 104 along the shape of the recess 104.

The scintillator 111 is a phosphor that is provided in the recess 104 formed on the second surface 103 of the sensor substrate 101 as described above and that converts the incident radiation 401 into light.

The reinforcing substrate 113 is a second substrate adhered to the second surface 103 (specifically, at least a part of the top 1041 of the recess) of the sensor substrate 101 and the scintillator 111 via the adhesive layer 112. is there. The reinforcing substrate 113 is a substrate for supporting and reinforcing the radiation imaging panel 110-1 including the sensor substrate 101 having the scintillator 111 provided in the recess 104. In this embodiment, the reinforcing substrate 113 is adhered to the scintillator 111 as well as the second surface 103 of the sensor substrate 101 via the adhesive layer 112. By adopting this form, the mechanical strength of the radiation imaging panel 110-1 can be improved as compared with the case where the reinforcing substrate 113 is bonded only to the second surface 103 of the sensor substrate 101 via the adhesive layer 112. Improvement can be realized.

Next, a method of manufacturing the radiation imaging panel 110-1 according to the first embodiment will be described.

First, in the manufacture of the radiation imaging panel 110-1, for example, a non-alkali glass substrate having a size of about 550 mm × 445 mm and a thickness of about 500 μm is prepared as a base material of the sensor substrate 101. Next, a film conversion process, a photolithography process, and an etching process are repeatedly performed on one surface of the glass substrate to convert a visible light into an electric charge (electrical signal) and a switching device that outputs the electric signal. A pixel region (effective pixel region 105 and dummy pixel region 106) in which a plurality of pixels including the elements are provided in a matrix to form the sensor substrate 101, and the sensor substrate 101 is formed on the first surface 102, respectively. A plurality of connection terminal portions 114 for outputting the electric signal generated by the pixel to the outside are formed.

After thus forming the sensor substrate 101 and the connection terminal portion 114, an array inspection for checking the operation of the pixels formed in the effective pixel region 105 is performed.

In this array inspection, if it is confirmed that the pixel operation is good and there is no defective pixel, first, the peripheral portion of the sensor substrate 101 is masked with a masking film for the purpose of protecting the connection terminal portion 114. Next, a slightly adhesive resin film is transferred onto the first surface 102 of the sensor substrate 101 for the purpose of protecting the effective pixel area 105 from hydrofluoric acid etching.

Subsequently, a mask pattern for forming the bottom 1043 of the recess is formed on the second surface 103 of the sensor substrate 101. Specifically, in the present embodiment, first, the second surface 103 of the sensor substrate 101 is set on the spin coater, and the photoresist is applied. Then, the sensor substrate 101 covered with the photoresist is placed on a UV exposure table and exposed using a predetermined photomask. Here, in the photomask, a region wider than the effective pixel region 105 of the sensor substrate 101 is opened in the orthogonal projection on the second surface 103 of the sensor substrate 101. This makes it possible to surely form the scintillator 111 formed in a region including the bottom 1043 of the recess in a subsequent step so as to cover the effective pixel region 105. After the exposure, the photoresist is developed by immersing the sensor substrate 101 in a sodium carbonate aqueous solution, and then rinsed with pure water and dried. In the present embodiment, the mask pattern formation is not limited to this mode. For example, it may be formed by a method of performing photolithography using a resist film, or may be formed by a method of transferring a protective film and cutting and peeling a desired region because the pattern is simple. In the case of this aspect, the photoresist process is not required, and thus the cost can be significantly reduced.

Subsequently, the sensor substrate 101 on which the mask pattern is formed is immersed in a 10% hydrofluoric acid solution. For example, the immersion time at this time is determined by a previously calculated etching rate, and etching is performed to a desired thickness. For example, in this embodiment, since the etching is performed to 400 μm, the thickness of the first surface 102 of the sensor substrate 101 and the bottom portion 1043 of the recess is about 100 μm. Then, after etching, the sensor substrate 101 is sufficiently rinsed with pure water and further immersed in a resist stripping solution to strip the mask pattern.

Subsequently, the resin film attached to the first surface 102 of the sensor substrate 101 is peeled off to form the sensor substrate 101 having the recess 104. In this way, the sensor substrate 101 is prepared.

Subsequently, the scintillator 111 is formed on the bottom 1043 of the recess and the side 1042 of the recess so as to fill the recess 104 along the shape of the recess 104. Specifically, in the present embodiment, first, the vapor deposition mask that covers the peripheral portion is set on the sensor substrate 101, and then the sensor substrate 101 is placed on the vapor deposition device so that the recess 104 becomes the vapor deposition surface. Next, cesium iodide (CsI) and thallium iodide (TlI) are co-evaporated so that the Tl concentration is about 1 mol% with respect to CsI, and the scintillator 111 having a film thickness of about 350 μm is formed. At this time, due to the nature of vapor deposition, the particles of the raw material adhere to the object while diffusing, so that the phosphor material also adheres to the outside of the vapor deposition mask, and as a result, not only the bottom 1043 of the recess but also the side 1042 of the recess. Also, the scintillator 111 is formed. Further, in the present embodiment, the outer edge of the scintillator 111 is located outside the outer edge of the effective pixel region 105.

In this state, the bottom 1043 of the concave portion of the sensor substrate 101 may be damaged by the total weight of the scintillator 111. Therefore, the reinforcement substrate 113 is arranged to reinforce the radiation imaging panel 110-1. Specifically, in this embodiment, first, as the reinforcing substrate 113, a non-alkali glass substrate having the same material as the sensor substrate 101 and a thickness of 0.5 mm is prepared. Next, the non-alkali glass substrate prepared as the reinforcing substrate 113 is placed on the thermal transfer device, and a layer of hot-melt resin having a thickness of about 30 μm, for example, as the adhesive layer 112 is thermally transferred onto the reinforcing substrate 113 to form the adhesive layer 112. The attached reinforcing substrate 113 is prepared.

Here, an example in which one kind of adhesive layer (a layer of hot melt resin) is used as the adhesive layer 112 has been described, but the present embodiment is not limited to this, and for example, the scintillator 111 and the top portion 1041 of the concave portion can be formed. Multiple adhesive layers suitable for each may be used. In the present embodiment, the adhesive layer 112 may be colored. In the present embodiment, for example, it is preferable that the adhesive layer 112 is colored as a white layer. For example, when the adhesive layer 112 is colored white with titanium oxide, alumina, or the like, of the light generated by the scintillator 111, light that travels in a direction different from the direction toward the effective pixel region 105 is reflected, so that the scintillator 111 can reflect the light. The generated light can be used efficiently. Thereby, the sensitivity of the radiation imaging panel 110-1 can be improved. Further, in the present embodiment, the reinforcing substrate 113 also has a function as a moisture-proof protective layer that protects the phosphor of the scintillator 111 from moisture. In this case, the thickness of the adhesive layer 112 is preferably 100 μm or less.

Subsequently, the sensor substrate 101 having the scintillator 111 formed in the recess 104 is placed on the thermal transfer device. Next, the reinforcing substrate 113 is bonded and bonded to the sensor substrate 101 and the scintillator 111 by thermal transfer so that the adhesive layer 112 contacts the top 1041 of the concave portion and the scintillator 111 in the second surface 103 of the sensor substrate 101. .. Thereby, the recess 104 of the sensor substrate 101 can be reinforced. At this time, in the present embodiment, the adhesive layer 112 is adhered not only to the top 1041 of the recess of the sensor substrate 101 and the scintillator 111 shown in FIG. 2 but also to a part of the side 1042 of the recess of the sensor substrate 101. It may have been done.

After that, the radiation imaging panel 110-1 in the present embodiment is formed by connecting the wiring material and the drive substrate to the connection terminal portion 114 via the anisotropic conductive film.

Then, a drive system was set on the radiation imaging panel 110-1 in this embodiment, and MTF and DQE were measured under the radiation quality condition of RQA5. As a result, the MTF at 2 lp / mm was 0.35 and the DQE was 0. It was 42. From this, in the radiation imaging panel 110-1 in the present embodiment, as a result of obtaining high MTF and DQE, it is possible to realize a sufficiently reliable high-performance radiation imaging panel.

As described above, in the radiation imaging panel 110-1 according to this embodiment, the reinforcing substrate 113 is bonded to the second surface 103 of the sensor substrate 101 and the scintillator 111 via the adhesive layer 112.

With this configuration, for example, the mechanical strength of the radiation imaging panel 110 is improved as compared with the case where the reinforcing substrate 113 is bonded only to the second surface 103 of the sensor substrate 101 via the adhesive layer 112. can do. As a result, it is possible to realize a sufficiently reliable and high-performance radiation imaging panel 110.

(Second embodiment)
Next, a second embodiment of the present invention will be described. In the description of the second embodiment described below, description of items common to the above-described first embodiment will be omitted, and items different from the above-described first embodiment will be described.

The schematic configuration of the radiation imaging system according to the second embodiment is similar to the schematic configuration of the radiation imaging system 10 according to the first embodiment shown in FIG. 1 described above. Therefore, the schematic configuration of the radiation imaging apparatus according to the second embodiment is similar to the schematic configuration of the radiation imaging apparatus 100 according to the first embodiment shown in FIG. 1 described above.

FIG. 3 is a diagram showing an example of a schematic configuration of the radiation imaging panel 110 of the radiation imaging apparatus 100 according to the second embodiment of the present invention. Similar to FIG. 2, FIG. 3 shows a cross-sectional view of the radiation imaging panel 110 in the incident direction of the radiation 401 shown in FIG. In the following description, the radiation imaging panel 110 according to the second embodiment shown in FIG. 3 will be described as a “radiation imaging panel 110-2”. Further, in FIG. 3, for example, X-rays can be applied as the radiation 401 shown in FIG.

As shown in FIG. 3, the radiation imaging panel 110-2 includes a sensor substrate 101, a scintillator 111, an adhesive layer 112, a reinforcing substrate 113, a connection terminal portion 114, a scintillator 115, and a reflective layer 116. There is. Further, in FIG. 3, in the sensor substrate 101, the first surface 102 located on the side where the radiation 401 enters, the second surface 103 located on the side opposite to the side where the radiation 401 enters, and the second surface 103. The recess 104 formed in the surface 103 is illustrated. Further, in FIG. 3, as specific portions forming the recess 104, the top 1041 of the recess, the side 1042 of the recess, and the bottom 1043 of the recess are illustrated. In FIG. 3, the same components as those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 3, the radiation imaging panel 110-2 according to the second embodiment has a configuration similar to that of the radiation imaging panel 110-1 according to the first embodiment shown in FIG. The scintillator 115 and the reflective layer 116 are sequentially formed on the surface 102 (more specifically, on the effective pixel region 105 and the dummy pixel region 106). The scintillator 115 is a scintillator different from the scintillator 111. Further, in the following description, the scintillator 111 will be described as a “first scintillator 111” and the scintillator 115 will be described as a “second scintillator 115”.

Each pixel of the effective pixel region 105 of the sensor substrate 101 in the present embodiment has an electric signal corresponding to the light converted from the radiation 401 by the first scintillator 111 and the light converted from the radiation 401 by the second scintillator 115. Is generated.

The second scintillator 115 is a phosphor that converts the radiation 401 incident through the reflective layer 116 into light.

The reflection layer 116 is provided so as to cover the second scintillator 115, and reflects, of the light generated by the second scintillator 115, light that travels in a direction different from the direction toward the effective pixel region 105 (the light is effective). It is a layer that reflects to lead to the pixel region 105. The reflective layer 116 makes it possible to efficiently use the light generated by the second scintillator 115 and improve the sensitivity of the radiation imaging panel 110-2. Further, it is more preferable that the reflective layer 116 has a function as a moisture-proof protective layer.

The other sensor substrate 101, the first scintillator 111, the adhesive layer 112, the reinforcing substrate 113, and the connection terminal portion 114 are the same as the respective components of the first embodiment shown in FIG. Omit it.

Next, a method of manufacturing the radiation imaging panel 110-2 according to the second embodiment will be described.

First, in the manufacture of the radiation imaging panel 110-2, the sensor substrate 101 is placed so that the first surface 102 faces upward, and the second scintillator 115 is not formed in a portion other than the recess 104. Masking on. Next, the sensor substrate 101 is placed on the vapor deposition device so that the first surface 102 of the sensor substrate 101 faces downward. Then, cesium iodide (CsI) and thallium iodide (TlI) are co-evaporated so that the Tl concentration is about 1 mol% with respect to CsI, and the second scintillator 115 with a film thickness of about 350 μm is formed.

Subsequently, the second scintillator 115 mounts the sensor substrate 101 formed on the first surface 102 on the thermal transfer device, and similarly to the first embodiment described above, the second surface 103 of the sensor substrate 101. The first scintillator 111 is formed in the concave portion 104. Then, similarly to the above-described first embodiment, the reinforcing substrate 113 is bonded and bonded to the sensor substrate 101 and the scintillator 111 via the adhesive layer 112. At this time, in the present embodiment, as the adhesive layer 112, a hot melt resin containing titanium oxide is used in order to have a function as a reflection layer.

Subsequently, the reflective layer 116 is formed so as to cover the second scintillator 115. Specifically, in the present embodiment, first, the sensor substrate 101 is placed on the thermal transfer device with the first surface 102 of the sensor substrate 101 facing upward. Then, the reflection layer 116 is formed by thermally transferring an aluminum thin film having a thickness of about 20 μm coated with a hot melt resin having a thickness of about 30 μm so as to completely cover the second scintillator 115.

After that, the radiation imaging panel 110-2 in the present embodiment is formed by connecting the drive substrates to the connection terminal portion 114 via the anisotropic conductive film. In this embodiment, the reinforcing substrate 113 and the reflective layer 116 also have a function as a moisture-proof protective layer.

When a drive system is set in the radiation imaging panel 110-2 in the present embodiment and X-rays are made to enter as radiation 401 in the direction of the arrow in FIG. 3 under the quality condition of RQA5, MTF and DQE are measured, The MTF at 2 lp / mm was 0.35. The DQE will be described below with reference to FIG.

FIG. 4 is a diagram of measurement results showing changes in DQE according to spatial frequency in the radiation imaging panel 110-2 according to the second embodiment of the present invention. In FIG. 4, for comparison, the measurement result 210 is the measurement result indicating the change in DQE of the radiation imaging panel 110-1 according to the first embodiment, and the measurement result 220 is the radiation imaging panel 110 according to the second embodiment. 2 is a measurement result showing a change in DQE of −2.

From the measurement results shown in FIG. 4, the DQE of the radiation imaging panel 110-2 according to the second embodiment is 3 lp / mm or less as compared with the DQE of the radiation imaging panel 110-1 according to the first embodiment. It can be seen that the value is high in the low frequency range. For this reason, the radiation imaging panel 110-2 according to the present embodiment can realize a highly reliable radiation imaging panel that can sufficiently withstand practical use.

As described above, in the radiation imaging panel 110-2 according to the present embodiment, the reinforcing substrate 113 is provided on the second surface 103 of the sensor substrate 101 and the scintillator 111 via the adhesive layer 112, as in the first embodiment. I try to adhere to it.

With this configuration, for example, the mechanical strength of the radiation imaging panel 110 is improved as compared with the case where the reinforcing substrate 113 is bonded only to the second surface 103 of the sensor substrate 101 via the adhesive layer 112. can do. Also from this viewpoint, according to the second embodiment, it is possible to realize a sufficiently reliable and high-performance radiation imaging panel 110.

(Third Embodiment)
Next, a third embodiment of the present invention will be described. In the description of the third embodiment described below, description of items common to the above-described first and second embodiments will be omitted, and items different from the above-described first and second embodiments will be described. I will explain.

The schematic configuration of the radiation imaging system according to the third embodiment is similar to the schematic configuration of the radiation imaging system 10 according to the first embodiment shown in FIG. 1 described above. Therefore, the schematic configuration of the radiation imaging apparatus according to the third embodiment is similar to the schematic configuration of the radiation imaging apparatus 100 according to the first embodiment shown in FIG. 1 described above.

The radiation imaging panel 110 according to the third embodiment has basically the same structure as the radiation imaging panel 110-2 according to the second embodiment, but the effective pixel region 105 (and the dummy pixel region 106 as well). Two types of pixels are formed as pixels to be formed (may be the same).

FIG. 5 is a diagram showing an example of a schematic configuration of the radiation imaging panel 110 of the radiation imaging apparatus 100 according to the third embodiment of the present invention. In the following description, the radiation imaging panel 110 according to the third embodiment shown in FIG. 5 will be described as a “radiation imaging panel 110-3”. In addition, FIG. 5 is a diagram showing, for example, only a region corresponding to the effective pixel region 105 shown in FIG. 3 in the configuration of the radiation imaging panel 110-3 according to the third embodiment when viewed from the incident direction of the radiation 401. Although shown, other configurations are assumed to have the configurations shown in FIG. Further, in FIG. 5, for example, X-rays can be applied as the radiation 401 shown in FIG.

As shown in FIG. 5, in the radiation imaging panel 110-3 according to the third embodiment, the normal pixel (first pixel) 301 and the pixel (second pixel) provided in the effective pixel region 105 (second pixel). Pixel) 302 are provided.

Similar to each pixel of the effective pixel area 105 in the second embodiment, the normal pixel 301 includes light converted from the radiation 401 by the first scintillator 111 and converted from the radiation 401 by the second scintillator 115. Both light and light are incident. Then, the normal pixel 301 generates an electric signal corresponding to these lights.

Specifically, in the present embodiment, the pixel 302 provided with the light shielding layer is located at a position between the second scintillator 115 and the effective pixel region 105, and the light converted from the radiation 401 by the second scintillator 115 is concerned. A light-blocking layer that suppresses incidence on the photoelectric conversion element of the pixel 302 is provided. Therefore, the light generated by the second scintillator 115 does not enter the pixel 302 provided with the light shielding layer, but only a part of the light generated by the first scintillator 111 enters. Then, the pixel 302 provided with the light shielding layer generates an electric signal according to the light generated and incident on the first scintillator 111.

In the radiation imaging panel 110-3 according to the third embodiment, when the radiation (X-ray) 401 is incident, the pixel 302 provided with the light shielding layer is beamed in the second scintillator 115 according to the third embodiment. Light based on the hardened high-energy component radiation (X-ray) 401 is captured. In addition, the normal pixel 301 includes light based on radiation (X-ray) 401 containing a low energy component which is not beam hardened and radiation (X-ray) 401 having a high energy component which is beam hardened by the second scintillator 115. It will capture both the light based on.

Here, when the signal value of the electric signal generated by the normal pixel 301 is A and the signal value of the electric signal generated by the pixel 302 provided with the light shielding layer is B,
AB = low energy image B = high energy image. That is, for example, by performing an appropriate interpolation process in the signal processing unit 121, it is possible to obtain a radiation image related to high and low energy. Then, for example, the signal processing unit 121 can perform energy subtraction processing using the high energy image and the low energy image obtained here. Here, the energy subtraction acquires a radiation image (may be referred to as a high energy image and a low energy image) using radiation having different energies of high energy and low energy, and the energy is calculated from the difference between these. It is a method of separating substances with different absorption rates and displaying them. For example, it is possible to separate bones from tissues other than bones, and it is expected that the diagnostic ability will be significantly improved.

Normally, high and low energy images can be easily acquired by exposing the radiation 401 twice. However, in the present embodiment, the energy subtraction image can be acquired by irradiating the radiation 401 once. That is, in the present embodiment, the exposure dose of the radiation 401 can be suppressed.

In the present embodiment, the arrangement pattern of the pixels 302 provided with the light shielding layer is not limited to the mode shown in FIG. 5 and can be changed as appropriate. At this time, if the ratio of the pixels 302 provided with the light shielding layer in the effective pixel region 105 is increased, the pixel pitch of the normal pixels 301 is widened, which may lead to deterioration in image quality of the obtained radiation image. The normal pixel 301 can be compensated by the image compensation technique similarly to the defective pixel which outputs an electric signal which is significantly different from the peripheral pixels, but when the ratio of the pixels 302 provided with the light shielding layer becomes high, the compensation is performed. Later image quality may be significantly degraded.

Therefore, for example, the number of pixels 302 provided with the light shielding layer is 1/2 of the total number of pixels in the effective pixel region 105 (the total number of ordinary pixels 301 and the number of pixels 302 provided with the light shielding layer). The normal pixel 301 and the pixel 302 provided with the light shielding layer may be adjusted as described below. Note that the present embodiment is not limited to this mode, and for example, the number of pixels 302 provided with the light shielding layer is 1/3 or less, or 1/4 or less of the total number of pixels in the effective pixel area 105. , Or 1/5 or less.

Next, a method of manufacturing the radiation imaging panel 110-3 according to the third embodiment will be described. Specifically, of the methods for manufacturing the radiation imaging panel 110-3, only the method for manufacturing the effective pixel region 105 (more specifically, the pixel 302 provided with the light shielding layer) will be described below, and other configurations will be described. The manufacturing method of is similar to that of the second embodiment described above, and thus the description thereof is omitted.

In the present embodiment, a mask pattern having an opening on a normal pixel 301 is formed by applying a photoresist in advance to the base material of the sensor substrate 101 and patterning it.

Next, a low-reflectance chromium dispersion liquid is applied by spin coating and developed to form a pixel 302 provided with a light shielding layer. In the present embodiment, the pixel 302 provided with the light shielding layer has, for example, a film thickness of about 1.2 μm and a visible light transmittance of about 1.0%, and can sufficiently shield light. Regarding the formation of the light-shielding layer, in addition to the above-described method, for example, there is a method using carbon black, a method of adjusting the opening of the back electrode, and the like. Applicable.

Further, the high and low energy images obtained by the above-described processing of this embodiment were subjected to image separation by the thickness t of each of the two substances by the method described below. Here, the signal value output from each pixel when the radiation 401 passes through a substance containing a plurality of components is expressed by the following equation (1).

In this equation (1), E represents the energy of the radiation 401, μ _i represents the linear attenuation constant of the component i, t _i represents the thickness of the component i, and N (E) represents the energy distribution of the irradiated radiation 401. Indicates. The thickness t _{i of} each component can be calculated by solving the integral equation using the observed signal values of the high and low energy images in the equation (1). At this time, in the present embodiment, the high energy signal value and the low energy signal value are respectively obtained as follows.
-High energy signal value = signal value observed in pixel 302-Low energy signal value = (median average value of signal values of eight peripheral pixels 301 surrounding pixel 302)-(signal value observed in pixel 302 )

FIG. 6 is a diagram showing an example of a bone separation image obtained by the radiation imaging apparatus 100 according to the third embodiment of the present invention. Specifically, in FIG. 6, the radiation source 400 having a tube voltage of 80 kV performs radiography of a hand phantom applied as the inspection target T, and the transmission image obtained by the radiography is used to perform the above-described (1). 7 illustrates a bone separation image acquired by processing of a formula. From FIG. 6, it is understood that the radiation imaging apparatus 100 according to the present embodiment can obtain a sufficiently high quality bone separation image.

Further, a drive system was set in the radiation imaging panel 110-3 in the present embodiment, and MTF and DQE were measured under the radiation quality condition of RQA5 by making X-rays as radiation 401 incident in the direction of the arrow in FIG. However, the behavior of MTF and DQE at 2 lp / mm was similar to that of the second embodiment described above. That is, also in the present embodiment, similar to the second embodiment, a high MTF and a high DQE can be obtained in a low frequency range of 3 lp / mm or less.

From the above, according to the radiation image pickup panel 110-3 of the present embodiment, in addition to the effects of the radiation image pickup panel 110 of the first and second embodiments, the radiation exposure panel 110-3 that is sufficiently practical can be used. It is possible to realize a reliable and high-performance radiation imaging panel 110 capable of energy subtraction.

In the present embodiment, the pixel 302 provided with the light shielding layer has the light shielding layer provided at a position between the second scintillator 115 and the effective pixel region 105. However, it is not limited to this form. For example, in the pixel 302 provided with the light shielding layer, the light shielding layer is provided at a position between the first scintillator 111 and the effective pixel region 105, light generated by the first scintillator 111 does not enter, and The mode in which the light generated by the second scintillator 115 is incident is also applicable to the present invention.

It should be noted that the above-described embodiments of the present invention are merely examples of embodying the present invention, and the technical scope of the present invention should not be limitedly interpreted by these. Is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

The present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are attached to open the scope of the present invention.

The present application claims priority on the basis of Japanese Patent Application No. 2018-2113680 filed on November 14, 2018, and the entire contents of the description are incorporated herein.

Claims

A plurality of pixels for converting light into an electric signal are provided on the first surface located on the side where the radiation enters, and a recess is provided on the second surface located on the side opposite to the first surface. Sensor board,
A scintillator provided in the recess and converting the radiation into the light,
A substrate bonded to the second surface and the scintillator via an adhesive layer,
A radiation imaging apparatus comprising:
The scintillator is provided on the bottom and side of the recess,
The radiation imaging apparatus according to claim 1, wherein the substrate is bonded to at least a part of a top portion of the second surface excluding the concave portion and the scintillator via the adhesive layer.
The radiation imaging apparatus according to claim 1 or 2, further comprising a scintillator that is provided on the side of the first surface of the sensor substrate and that is different from the scintillator that converts the radiation into the light.
A plurality of said pixels,
A first pixel for converting the light converted by the scintillator and the light converted by the other scintillator into the electric signal;
A second pixel for converting the light converted by the scintillator into the electric signal;
The radiation imaging apparatus according to claim 3, further comprising:
The radiation imaging apparatus according to claim 4, wherein the second pixel is provided with a light blocking layer that blocks the light converted by the other scintillator between the second pixel and the other scintillator.
The radiation imaging apparatus according to any one of claims 1 to 5, wherein the adhesive layer is a layer of hot melt resin.
The radiation imaging apparatus according to any one of claims 1 to 6, wherein the adhesive layer is a white layer.
A control unit for controlling the operation of the plurality of pixels,
A signal processing unit that processes the electrical signals output from the plurality of pixels;
The radiation imaging apparatus according to any one of claims 1 to 7, further comprising:
A radiation imaging apparatus according to claim 1;
A radiation source for emitting the radiation;
A radiation imaging system comprising:
A method of manufacturing a radiation imaging apparatus, which acquires incident radiation as an electric signal,
A plurality of pixels for converting light into the electric signals are provided on the first surface located on the side where the radiation is incident, and a recess is formed on the second surface located on the side opposite to the first surface. A step of preparing the provided sensor substrate,
Forming a scintillator for converting the radiation into the light in the recess;
Bonding a substrate to the second surface and the scintillator via an adhesive layer,
A method of manufacturing a radiation imaging apparatus, comprising: