WO2012002224A1

WO2012002224A1 - Radiation detector and method of producing same

Info

Publication number: WO2012002224A1
Application number: PCT/JP2011/064281
Authority: WO
Inventors: 中津川　晴康; 成行　書史; 西納　直行; 大田　恭義; 岩切　直人
Original assignee: 富士フイルム株式会社
Priority date: 2010-06-30
Filing date: 2011-06-22
Publication date: 2012-01-05
Also published as: JP2012013533A

Abstract

Disclosed is a radiation detector that is highly sensitive to radiation due to the weight reduction of a substrate for deposition. Also disclosed is a method of producing the radiation detector. The substrate for deposition (104) comprises a plurality of substrates (100, 60) that are laminated via an adhesion layer (102). The radiation detector comprises: a scintillator layer (36) that is deposited on the substrate for deposition (104), and that converts incident radiation into light; and a TFT substrate (30) that is pasted to the scintillator layer (36), and that converts the light emitted from the scintillator layer (36) into a charge. By removing the outside substrate (100) from the inside substrate (60) among the abovementioned plurality of substrates, the weight of the substrate for deposition (104) is reduced.

Description

Radiation detector and manufacturing method thereof

The present invention relates to a radiation detector and a manufacturing method thereof.

In recent years, radiation detectors such as FPD (Flat Panel Detector) that can directly convert radiation into digital data have been put into practical use. This radiation detector has an advantage that an image can be confirmed immediately compared to a conventional imaging plate, and is rapidly spreading.

Various types of radiation detectors have been proposed. For example, radiation is once converted into light by a scintillator layer such as CsI: Tl, GOS (Gd ₂ O ₂ S: Tb), and the converted light is converted into a semiconductor. There is an indirect conversion method in which the charge is converted and accumulated in a layer.

When manufacturing an indirect conversion type radiation detector, there is a case in which a scintillator layer is deposited on a deposition substrate, and then a step of attaching a light detection substrate that converts light into electric charges is performed on the scintillator layer. is there.
In this case, when the radiation detector is manufactured, the deposition substrate needs to have a certain thickness in order to improve handling, prevent warping due to the weight of the scintillator layer, and prevent deformation due to radiant heat.

However, after manufacturing the radiation detector, if the thickness of the deposition substrate is large, the radiation detector becomes heavy. In addition, the radiation irradiated to the deposition substrate is absorbed more and the sensitivity of the radiation detector is lowered.

Therefore, Patent Document 1 (Japanese Patent Application Laid-Open No. 11-101895) discloses a process in which a photodetection substrate is attached to a scintillator layer on a deposition substrate and then the deposition substrate is removed.

Patent Document 2 (Japanese Patent Application Laid-Open No. 2008-190929) discloses that a photodetection substrate is attached to a scintillator layer on a deposition substrate, and then the back surface (outer surface) of the deposition substrate is etched or polished. Thus, a process of thinning the deposition substrate is disclosed.

However, in the process of Patent Document 1, the scintillator layer on the substrate may be damaged in the process of removing the deposition substrate. In particular, when the scintillator layer is composed of a plurality of columnar crystals, the scintillator layer may lose its balance and cause damage itself after the deposition substrate is removed.

Further, in the process of Patent Document 2, since the substrate for deposition is thinned by etching or polishing, it takes time to make the thickness of the substrate uniform. In addition, if the thickness is not uniform even if the thickness is reduced, radiation scattering or the like may occur, and the sensitivity of the radiation detector may decrease.

The present invention has been made in view of the above-described facts, and an object thereof is to provide a radiation detector that is lightweight and highly sensitive to radiation, and a method for manufacturing the same.

The method of manufacturing a radiation detector according to the first aspect of the present invention includes a deposition step of depositing a scintillator layer that converts incident radiation into light on a plurality of stacked substrates, and the scintillator layer on the scintillator layer. A sticking step of attaching a light detection substrate that converts light emitted from the substrate into an electrical signal, and a step of removing the outer substrate from the substrate on which the scintillator layer is deposited.

According to this method, since the scintillator layer is deposited on a plurality of stacked substrates in the deposition step, the scintillator layer can be deposited after increasing the thickness of the entire substrate, and the handling property can be improved. Warpage due to the weight of the layer can be prevented, and deformation due to radiant heat can be prevented.
Further, in the removal step after the pasting step, the outer substrate is removed from the substrate on which the scintillator layer is deposited, so that the thickness of the substrate can be reduced, and the thickness of the inner substrate can be uneven. In addition, the radiation detector can be reduced in weight. Furthermore, since the absorption of radiation is reduced when the thickness of the substrate is reduced, the sensitivity of the radiation detector can be increased.
In the removal step, the outer substrate is removed from the substrate on which the scintillator layer is deposited, so that the inner substrate remains, and the scintillator layer is not damaged during the removal step.

In addition, if the thickness of the entire substrate is large, the amount of thermal expansion increases, the difference between the amount of thermal expansion of the light detection substrate widens, and there is a possibility that the radiation detector will thermally expand due to temperature change and warp. By removing the outer substrate from the plurality of stacked substrates, the thickness of the substrate proportional to the thermal expansion amount can be reduced, and the warp of the radiation detector can be suppressed. Moreover, the thickness of the substrate can be reduced to suppress the warping force of the radiation detector.

In the method of manufacturing a radiation detector according to the second aspect of the present invention, in the first aspect, the stacked substrates are bonded to each other with an adhesive.

According to this method, even when the scintillator layer is deposited from the lower side to the upper side in the gravitational direction in order to prevent a foreign substance or the like from falling on the plurality of stacked substrates during the scintillator layer deposition step, It is possible to suppress peeling of the substrates due to the weight. In the removal step, the outer substrate can be easily removed by peeling off the adhesive.

According to a third aspect of the present invention, there is provided the radiation detector manufacturing method according to the second aspect, wherein the stacked substrates are two, the outer substrate is transparent, and the adhesive is made of ultraviolet rays. In the removal step, the substrate is removed by irradiating ultraviolet rays from the outer substrate side.

According to this method, the outer substrate of the two stacked substrates can be easily removed by ultraviolet irradiation.

In the radiation detector manufacturing method according to a fourth aspect of the present invention, in the second aspect, the stacked substrates are two, and the outer substrate is provided with a hole penetrating the substrate. In the removing step, the substrate is removed by pouring a release agent from above the outer substrate into the hole.

According to this method, the outer substrate can be easily removed from the two stacked substrates by pouring the release agent from the outer substrate.

In the method for manufacturing a radiation detector according to the fifth aspect of the present invention, in any one of the first to fourth aspects, a cut is made in the inner substrate after the removing step.

This method can further suppress the warpage of the radiation detector.

The method of manufacturing a radiation detector according to a sixth aspect of the present invention is the method of manufacturing a radiation detector according to any one of the first to fifth aspects, wherein the deposition step includes a plurality of columnar crystals by a vapor deposition method. Deposit a scintillator layer.

Thus, even when the scintillator layer including a plurality of columnar crystals is deposited, only the outer substrate can be removed and the inner substrate can be left out of the plurality of stacked substrates, so that the scintillator layer loses its balance. Will not cause any damage.

A radiation detector according to a seventh aspect of the present invention includes a plurality of stacked substrates, a scintillator layer that is deposited on the substrate and converts incident radiation into light, and is attached to the scintillator layer, A light detection substrate that converts light emitted from the scintillator layer into electric charge.

According to this configuration, for example, at the time of manufacturing a radiation detector, a plurality of substrates are stacked, the thickness of the entire substrate is increased, handling properties are improved, or warping due to the weight of the scintillator layer is prevented, It is possible to prevent deformation due to radiant heat.
In addition, after manufacturing the radiation detector, the thickness of the substrate can be reduced by removing the outer substrate from the plurality of stacked substrates, so that the thickness of the substrate does not become uneven. The weight of the radiation detector can be reduced. Furthermore, since the absorption of radiation is reduced when the thickness of the substrate is reduced, the sensitivity of the radiation detector can be increased.
Further, since it is only necessary to remove the outer substrate, the scintillator layer is not damaged.

In the radiation detector according to the eighth aspect of the present invention, in the seventh aspect, the plurality of stacked substrates are bonded to each other with an adhesive.

According to this configuration, even when the scintillator layer is deposited from the lower side to the upper side in the gravitational direction in order to prevent the fall of foreign matters or the like on the plurality of stacked substrates at the time of manufacture, It can suppress that each other peels. Further, after manufacturing, the outer substrate can be easily removed by peeling off the adhesive.

The radiation detector according to a ninth aspect of the present invention is the radiation detector according to the eighth aspect, wherein the plurality of stacked substrates are two, the outer substrate is transparent, and the adhesive is the outer substrate. Can be peeled off by ultraviolet rays that pass through.

According to this configuration, the outer substrate of the two stacked substrates can be easily removed by ultraviolet irradiation.

The radiation detector according to a tenth aspect of the present invention is the radiation detector according to the eighth aspect, wherein the plurality of stacked substrates are two, and the outer substrate is provided with a hole penetrating the substrate, The adhesive can be peeled by the release agent that has passed through the hole.

According to this configuration, the outer substrate can be easily removed from the two stacked substrates by pouring the release agent from the outer substrate.

The radiation detector according to an eleventh aspect of the present invention is the radiation detector according to any one of the seventh to tenth aspects, wherein the scintillator layer includes a plurality of columnar crystals.

Even if the scintillator layer includes a plurality of columnar crystals, it is possible to remove only the outer substrate and leave the inner substrate among the plurality of stacked substrates, so that the scintillator layer loses its balance. It does not cause damage on its own.

According to the present invention, it is possible to provide a radiation detector that is lightweight and highly sensitive to radiation, and a method for manufacturing the same.

It is the schematic which shows arrangement | positioning of the electronic cassette at the time of radiographic image photography. It is a schematic perspective view which shows the internal structure of the electronic cassette shown in FIG. It is a figure which shows the circuit diagram of the electronic cassette shown in FIG. It is sectional drawing which showed the cross-sectional structure of the electronic cassette shown in FIG. It is the figure which showed the manufacturing process of the radiation detector which concerns on 1st Embodiment of this invention, Comprising: It is a figure which shows a board | substrate preparation process especially. It is the figure which showed the manufacturing process of the radiation detector concerning 1st Embodiment of this invention, Comprising: It is a figure which shows a deposition process especially. It is the figure which showed the manufacturing process of the radiation detector which concerns on 1st Embodiment of this invention, Comprising: It is a figure which shows a sticking process especially. It is the figure which showed the manufacturing process of the radiation detector which concerns on 1st Embodiment of this invention, Comprising: It is a figure which shows a removal process especially. It is a figure showing a manufacturing process of a radiation detector concerning a 1st embodiment of the present invention, and is a figure showing a radiation detector concerning a 1st embodiment of the present invention especially. It is the figure which showed the manufacturing process of the radiation detector which concerns on 2nd Embodiment of this invention, Comprising: It is a figure which shows a board | substrate preparation process especially. It is the figure which showed the manufacturing process of the radiation detector which concerns on 2nd Embodiment of this invention, Comprising: It is a figure which shows a deposition process especially. It is the figure which showed the manufacturing process of the radiation detector which concerns on 2nd Embodiment of this invention, Comprising: It is a figure which shows a sticking process especially. It is the figure which showed the manufacturing process of the radiation detector which concerns on 2nd Embodiment of this invention, Comprising: It is a figure which shows a removal process especially. It is the figure which showed the manufacturing process of the radiation detector which concerns on 2nd Embodiment of this invention, Comprising: It is a figure which shows the radiation detector which concerns on 2nd Embodiment of this invention especially.

(First embodiment)
Hereinafter, a radiation detector and a manufacturing method thereof according to a first embodiment of the present invention will be specifically described with reference to the accompanying drawings. In the drawings, members (components) having the same or corresponding functions are denoted by the same reference numerals and description thereof is omitted as appropriate.

-Overall configuration of radiation imaging equipment-
First, the configuration of an electronic cassette as an example of a radiographic imaging apparatus incorporating a radiation detector according to the first embodiment of the present invention will be described.

The electronic cassette is portable, detects radiation from a radiation source that has passed through the subject, generates image information of a radiation image represented by the detected radiation, and can store the generated image information This is a photographing apparatus, and specifically configured as shown below. The electronic cassette may be configured not to store the generated image information.

FIG. 1 is a schematic diagram showing the arrangement of electronic cassettes during radiographic imaging.

The electronic cassette 10 is arranged at a distance from the radiation generation unit 12 as a radiation source for generating the radiation X at the time of capturing a radiation image. The space between the radiation generation unit 12 and the electronic cassette 10 at this time is an imaging position for the patient 14 as a subject to be positioned. When an instruction to capture a radiographic image is given, the radiation generation unit 12 gives in advance. Radiation X having a radiation dose according to the imaging conditions is emitted. The radiation X emitted from the radiation generation unit 12 passes through the patient 14 located at the imaging position, and is then applied to the electronic cassette 10 after carrying image information.

FIG. 2 is a schematic perspective view showing the internal structure of the electronic cassette 10.

The electronic cassette 10 is made of a material that transmits the radiation X and includes a flat casing 16 having a predetermined thickness. And the radiation detector 20 which detects the radiation X which permeate | transmitted the patient 14 from the irradiation surface 18 side of the housing | casing 16 where radiation X is irradiated inside this housing | casing 16, and the said radiation detector 20 are controlled. A control board 22 is provided in order.

FIG. 3 is a circuit diagram of the electronic cassette 10.

The radiation detector 20 includes an upper electrode, a semiconductor layer, and a lower electrode, and includes a sensor unit 24 that accumulates charges by receiving light, and a TFT switch 26 for reading out the charges accumulated in the sensor unit 24. The pixel 28 to be configured includes a TFT (Thin FilmorTransistor) active matrix substrate 30 (hereinafter referred to as a TFT substrate) in which a large number of two-dimensional pixels 28 are provided.

Further, on the TFT substrate 30, a plurality of scanning wirings 32 for turning on / off the above-described TFT switch 26 and a plurality of signal wirings 34 for reading out electric charges accumulated in the sensor unit 24 intersect each other. Is provided.

In the radiation detector 20 according to the first embodiment of the present invention, the scintillator layer 36 is attached to the surface of the TFT substrate 30.

The scintillator layer 36 converts radiation X such as irradiated X-rays into light. The sensor unit 24 receives the light emitted from the scintillator layer 36 and accumulates electric charges.

Each signal wiring 34 has an electrical signal (image signal) indicating a radiation image in accordance with the amount of charge accumulated in the sensor unit 24 when any TFT switch 26 connected to the signal wiring 34 is turned on. Is flowing.

Further, a plurality of connection connectors 38 are arranged side by side on one end side in the signal wiring 34 direction of the radiation detector 20, and a plurality of connectors 40 are arranged on one end side in the scanning wiring 32 direction. Yes. Each signal wiring 34 is connected to a connector 38, and each scanning wiring 32 is connected to a connector 40.

One end of a flexible cable 42 is electrically connected to these connectors 38. One end of the flexible cable 44 is electrically connected to the connector 40.
The flexible cable 42 and the flexible cable 44 are coupled to the control board 22.

The control board 22 is provided with a control unit 46 for controlling the imaging operation by the radiation detector 20 and controlling the signal processing for the electric signal flowing through each signal wiring 34. The control unit 46 includes a signal detection circuit 48 and a control unit 46. And a scan signal control circuit 50.

The signal detection circuit 48 is provided with a plurality of connectors 52, to which the other end of the flexible cable 42 is electrically connected. The signal detection circuit 48 incorporates an amplification circuit for amplifying an input electric signal for each signal wiring 34. With this configuration, the signal detection circuit 48 amplifies and detects the electric signal input from each signal wiring 34 by the amplification circuit, and is stored in each sensor unit 24 as information of each pixel 28 constituting the image. Detect the amount of charge.

On the other hand, the scan signal control circuit 50 is provided with a plurality of connectors 54, and the other end of the flexible cable 44 described above is electrically connected to these connectors 54. A control signal for turning on / off the TFT switch 26 can be output to each scanning wiring 32.

When taking a radiographic image in such a configuration, the radiation detector 20 is irradiated with the radiation X transmitted through the patient 14. The irradiated radiation X is converted into light by the scintillator layer 36 and irradiated to the sensor unit 24. The sensor unit 24 receives the light emitted from the scintillator layer 36 and accumulates electric charges.

At the time of image reading, an ON signal (+10 to 20 V) is sequentially applied from the scan signal control circuit 50 to the gate electrode of the TFT switch 26 of the radiation detector 20 through the scan wiring 32. Thereby, when the TFT switch 26 of the radiation detector 20 is sequentially turned on, an electrical signal corresponding to the amount of charge accumulated in the sensor unit 24 flows out to the signal wiring 34. The signal detection circuit 48 detects the amount of electric charge accumulated in each sensor unit 24 based on the electric signal that has flowed out to the signal wiring 34 of the radiation detector 20 as information of each pixel 28 constituting the image. Thereby, the image information which shows the image shown with the radiation irradiated to the radiation detector 20 is obtained.

-Cross-sectional configuration of electronic cassette 10-
Next, the configuration of the electronic cassette 10 will be described more specifically. FIG. 4 is a cross-sectional view showing a cross-sectional configuration of the electronic cassette 10.

As shown in the figure, the electronic cassette 10 contains the control board 22 and the radiation detector 20 in the housing 16 in order from the opposite side of the irradiation surface 18 irradiated with the radiation X.
The control board 22 is placed on the bottom surface inside the housing 16 via a support leg 22A, and the radiation detector according to the first embodiment of the present invention is provided via the flexible cable 42 and the flexible cable 44 described above. 20 is connected.
In the following embodiments, “up” refers to the direction from the control board 22 side to the radiation detector 20 side, and “down” refers to the direction from the radiation detector 20 side to the control board 22 side. .

The radiation detector 20 according to the first embodiment of the present invention has a rectangular flat plate shape, and detects a radiation image represented by the radiation X transmitted through the patient 14 as described above. The radiation detector 20 includes a TFT substrate 30, a scintillator layer 36, and a substrate 60 for depositing the scintillator layer 36.

The TFT substrate 30 is placed on the control substrate 22, and the above-described TFT switch 26 and sensor unit 24 are formed on a substrate (not shown).
As a substrate material of the TFT substrate 30, for example, an inorganic material such as YSZ (zirconia stabilized yttrium), glass, saturated polyester resin, polyethylene terephthalate (PET) resin, polyethylene naphthalate (PEN) resin, polybutylene. Terephthalate resin, polystyrene, polycycloolefin, norbornene resin, poly (chlorotrifluoroethylene), cross-linked fumaric acid diester resin, polycarbonate (PC) resin, polyether sulfone (PES) resin, polysulfone (PSF, PSU) Resin, polyarylate (PAR) resin, allyl diglycol carbonate, cyclic polyolefin (COP, COC) resin, cellulose resin, polyimide (PI) resin, polyamideimide (PARI) resin, maleimide-olefin resin, polyamido Organic materials such as (Pa) resin, acrylic resin, fluorine resin, epoxy resin, silicone resin film, polybenzazole resin, episulfide compound, liquid crystal polymer (LCP), cyanate resin, aromatic ether resin Etc. Other composite plastic materials with silicon oxide particles, composite plastic materials with metal nanoparticles / inorganic oxide nanoparticles / inorganic nitride nanoparticles, composites with metal / inorganic nanofibers and / or microfibers Plastic material, carbon fiber, composite plastic material with carbon nanotube, composite plastic material with glass ferret, glass fiber, glass bead, composite plastic material with clay mineral or particles with mica derived crystal structure, thin glass and above alone By alternately laminating a laminated plastic material or inorganic layer (for example, SiO ₂ , Al ₂ O ₃ , SiO _x N _y ) having at least one bonding interface with an organic material and an organic layer made of the above-described material. , Having a barrier performance having at least one bonding interface Aluminum with an oxide film whose surface insulation is improved by applying an oxidation treatment (for example, anodizing treatment) to a composite material, stainless steel, or a metal laminate material obtained by laminating stainless and different metals, an aluminum substrate, or the surface. A substrate can also be used. In the case of the organic material, it is preferable that the organic material is excellent in dimensional stability, solvent resistance, electrical insulation, workability, low air permeability, low hygroscopicity, and the like.

Further, as a substrate material of the TFT substrate 30, bionanofiber can also be used. The bionanofiber is a composite of a cellulose microfibril bundle (bacterial cellulose) produced by bacteria (Acetobacter Xylinum) and a transparent resin. The cellulose microfibril bundle has a width of 50 nm and a size of 1/10 of the visible light wavelength, and has high strength, high elasticity, and low thermal expansion. By impregnating and curing a transparent resin such as acrylic resin or epoxy resin into bacterial cellulose, a bio-nanofiber having a light transmittance of about 90% at a wavelength of 500 nm can be obtained while containing 60-70% of the fiber. Bionanofiber has a low coefficient of thermal expansion (3-7ppm) comparable to silicon crystals, and is as strong as steel (460MPa), highly elastic (30GPa), and flexible. Compared to glass substrates, etc. A thin TFT substrate 30 can be formed.
A colorless and transparent aramid film can also be used. This aramid film has heat resistance up to 315 ° C., and has an advantageous feature that it has a low thermal expansion rate and is less prone to cracking since it has a thermal expansion coefficient close to that of a glass substrate.

The above-described scintillator layer 36 is attached to the upper surface of the TFT substrate 30. The scintillator layer 36 has a structure including a plurality of columnar crystals, and a gap is formed between the columnar crystals.
Examples of the material of the scintillator layer 36 include CsI: Tl, CsI: Na (sodium-activated cesium iodide), ZnS: Cu, and CsBr.

On the upper surface of the scintillator layer 36, a deposition substrate 60 used when the scintillator layer 36 is formed by a vapor deposition method is provided.
The material of the substrate 60 is not particularly limited, and the same material as the TFT substrate 30 such as glass, bionanofiber, and aramid film can be used. However, from the viewpoint that the warpage of the radiation detector 20 can be suppressed, the thermal expansion coefficient is substantially the same as the thermal expansion coefficient of the TFT substrate 30 (difference in the thermal expansion coefficient is within several PPM / ° C., for example, within 5 PPM / ° C.). It is preferable to use one.

The thickness of the substrate 60 is preferably thinner from the viewpoint of reducing the weight of the substrate 60 to reduce the weight of the radiation detector 20 and reducing the absorption of the radiation X.
The substrate 60 is preferably not warped, but may be warped to a maximum of 14 mm in the temperature range of −30 ° C. to 50 ° C., for example, in consideration of the space inside the housing 16 of the electronic cassette 10. In order to control such warpage, the thickness of the substrate 60 may be determined in consideration of the thickness of the TFT substrate 30.

The irradiation surface 18 of the housing 16 is disposed on the upper surface side of the substrate 60 via a gap, and the surface of the irradiation surface 18 is irradiated with the radiation X from the irradiation surface 18. That is, irradiation is performed from the front side to which the scintillator layer 36 of the radiation detector 20 is bonded.

-Manufacturing method of radiation detector 20-
Next, a method for manufacturing the radiation detector 20 according to the first embodiment of the present invention will be described.

5A and 5B are diagrams showing a manufacturing process of the radiation detector 20 according to the first embodiment of the present invention. FIG. 5A is a diagram showing a substrate preparation process, and FIG. 5B is a diagram showing a deposition process. FIG. 5C is a view showing the attaching step, FIG. 5D is a view showing the removing step, and FIG. 5E is a view showing the radiation detector 20 according to the first embodiment of the present invention.

1. Substrate Preparation Step First, as shown in FIG. 5A, a substrate preparation step is performed in which two substrates, the above-described substrate 60 and a substrate 100 for reinforcing the substrate 60, are prepared. Hereinafter, these two substrates are referred to as an inner substrate 60 and an outer substrate 100 for convenience.
The material of the outer substrate 100 is not particularly limited as long as it is a transparent material that can transmit ultraviolet rays, which will be described later, and the same material as the TFT substrate 30 and the substrate 60 can be used. preferable.
The materials of the outer substrate 100 and the inner substrate 60 have substantially the same thermal expansion coefficient (difference in thermal expansion coefficient) so that the outer substrate 100 and the inner substrate 60 do not warp when gradually increasing from room temperature to the deposition temperature described later. Is preferably several PPM / ° C., for example, within 5 PPM / ° C.). Specifically, as a combination of materials of the outer substrate 100 and the inner substrate 60, the same material such as thick glass / thin glass, or a material having a difference in thermal expansion coefficient such as glass / aramid, aramid / glass, etc. within several PPM / ° C. Can be mentioned.

The thickness of the outer substrate 100 is preferably larger than the thickness of the inner substrate 60 from the viewpoint of reducing the inner substrate 60.

After the two outer substrates 100 and the inner substrate 60 are prepared as described above, these are bonded and laminated by the adhesive 102 that can be peeled off by ultraviolet rays, and the deposition substrate 104 of the scintillator layer 36 is obtained.
The material of the adhesive 102 is not particularly limited as long as it is peeled off by ultraviolet rays and can maintain adhesive force even at a deposition temperature (for example, 200 ° C.) of a scintillator layer 36 described later.

2. Deposition Step Next, as shown in FIG. 5B, a deposition step is performed in which the scintillator layer 36 is deposited on the inner substrate 60 of the deposition substrate 104 by a vapor deposition method.
Specifically, an embodiment using CsI: Tl will be described as an example.
The vapor deposition method can be performed by a conventional method. That is, in an environment having a degree of vacuum of 0.01 to 10 Pa, CsI: Tl is heated and vaporized by means such as energizing a resistance heating crucible, and the temperature (evaporation temperature) of the deposition substrate 104 is room temperature (20 ° C.). ) To 300 ° C. CsI: Tl may be deposited and deposited on the deposition substrate 104.
When the CsI: Tl crystal phase is formed on the deposition substrate 104 by the vapor deposition method, initially, an aggregate of crystals having a relatively small diameter of an amorphous or substantially spherical crystal is formed. In carrying out the vapor deposition method, by changing at least one of the conditions of the degree of vacuum and the temperature of the deposition substrate 104, columnar crystals can be grown continuously by the vapor deposition method after the non-columnar crystal region is formed. Can do.
That is, after forming the non-columnar crystal region, uniform columnar crystals can be efficiently grown by performing at least one of the means such as increasing the degree of vacuum and increasing the temperature of the deposition substrate 104.

3. Next, as shown in FIG. 5C, a pasting step is performed in which the TFT substrate 30 is pasted to the scintillator layer 36 using the adhesive 106.

4). Removal Step Next, as shown in FIG. 5D, a removal step of removing the outer substrate 100 from the inner substrate 60 on which the scintillator layer 36 is deposited is performed.
Specifically, ultraviolet rays UV are irradiated from the outside of the outer substrate 100, the transparent outer substrate 100 is transmitted, the adhesive 102 is peeled off, and the outer substrate 100 is removed.

5. Acquisition of Radiation Detector 20 Through the above steps, the radiation detector 20 as shown in FIGS. 5E and 4 can be acquired.

-Action-
According to the method for manufacturing the radiation detector 20 according to the first embodiment of the present invention, the scintillator layer 36 is deposited on the deposition substrate 104 in which the two

substrates

100 and 60 are laminated in the deposition process. The scintillator layer 36 can be deposited after increasing the thickness of the entire deposition substrate 104. Therefore, handling properties can be improved, warpage due to the weight of the scintillator layer 36 can be prevented, and deformation due to radiant heat can be prevented.
Further, in the removal step after the attaching step, the outer substrate 100 is removed from the inner substrate 60 on which the scintillator layer 36 is deposited, so that the thickness of the deposition substrate 104 remaining after the manufacture of the radiation detector 20 can be reduced. The radiation detector 20 can be reduced in weight without the thickness of the inner substrate 60 becoming uneven. Furthermore, since the absorption of the radiation X is reduced when the thickness of the deposition substrate 104 is reduced, the sensitivity of the radiation detector 20 can be increased.
In the removal step, the outer substrate 100 is removed from the inner substrate 60 on which the scintillator layer 36 is deposited, so that the inner substrate 60 remains and does not damage the scintillator layer 36 during the removal step. .

In addition, if the thickness of the deposition substrate 104 is large, the amount of thermal expansion increases, and the difference from the amount of thermal expansion of the light detection substrate widens, and the radiation detector 20 may be warped due to thermal expansion due to temperature change. However, by removing the outer substrate 100 from the deposition substrate 104, the thickness of the deposition substrate 104 that is proportional to the amount of thermal expansion can be reduced, and the warpage of the radiation detector 20 can be suppressed. Further, the thickness of the deposition substrate 104 can be reduced to suppress the warping force of the radiation detector 20.

Further, the outer substrate 100 and the inner substrate 60 constituting the deposition substrate 104 are bonded to each other with an adhesive 102. Therefore, even when the scintillator layer 36 is deposited from the lower side to the upper side in the direction of gravity in order to prevent the fall of foreign matter or the like on the deposition substrate 104 during the deposition process of the scintillator layer 36, It is possible to prevent the outer substrate 100 and the inner substrate 60 from peeling off. Further, after manufacturing, the outer substrate 100 can be easily removed by removing the adhesive 102.

Further, since the adhesive 102 is peeled off by irradiating ultraviolet rays UV from the outer substrate 100 side, the outer substrate 100 can be easily removed from the deposition substrate 104.

In the deposition process, the scintillator layer 36 including a plurality of columnar crystals is deposited by a vapor deposition method. Even when the scintillator layer 36 including a plurality of columnar crystals is deposited in this manner, only the outer substrate 100 can be removed from the deposition substrate 104 and the inner substrate 60 can be left, so that the scintillator layer 36 loses its balance. It does not cause damage on its own.

(Second Embodiment)
Next, a radiation detector 200 and a method for manufacturing the same according to a second embodiment of the present invention will be described.

-Manufacturing method of radiation detector 200-
6A and 6B are diagrams showing a manufacturing process of the radiation detector 200 according to the second embodiment of the present invention. FIG. 6A is a diagram showing a substrate preparation process, and FIG. 6B is a diagram showing a deposition process. FIG. 6C is a view showing the attaching step, FIG. 6D is a view showing the removing step, and FIG. 6E is a view showing the radiation detector 200 according to the second embodiment of the present invention.

1. Substrate Preparation Step First, as shown in FIG. 6A, a substrate preparation step of preparing two substrates, the substrate 60 described above and a substrate 202 for reinforcement of the substrate 60, is performed. Hereinafter, these two substrates are referred to as an inner substrate 60 and an outer substrate 202 for convenience.
The outer substrate 202 is provided with a plurality of holes 204 that penetrate the outer substrate 202. The material of the outer substrate 202 may not be a transparent material unlike the outer substrate 100 of the first embodiment, and the same material as the TFT substrate 30 and the inner substrate 60 can be used. Carbon can be used.
The materials of the outer substrate 202 and the inner substrate 60 have substantially the same thermal expansion coefficient (difference in thermal expansion coefficient) so that the outer substrate 202 and the inner substrate 60 do not warp when gradually increasing from room temperature to a deposition temperature described later. Is preferably several PPM / ° C., for example, within 5 PPM / ° C.). Specifically, as a combination of materials of the outer substrate 202 and the inner substrate 60, a material having a difference in thermal expansion coefficient such as carbon / glass or the like within several PPM / ° C. can be cited.

After the two outer substrates 202 and the inner substrate 60 are prepared as described above, the substrates 206 are laminated by bonding with the adhesive 206 to obtain the deposition substrate 208 of the scintillator layer 36.
The material of the adhesive 206 is not particularly limited as long as it can maintain the adhesive force even at the deposition temperature (for example, 200 ° C.) of the scintillator layer 36.

2. Deposition Step Next, as shown in FIG. 6B, a deposition step is performed in which the scintillator layer 36 is deposited on the inner substrate 60 of the deposition substrate 208 by a vapor deposition method. The specific method of the vapor deposition method is the same as that described in the first embodiment.

3. Next, as shown in FIG. 6C, a pasting step is performed in which the TFT substrate 30 is pasted on the scintillator layer 36 using an adhesive 106.

4). Removal Step Next, as shown in FIG. 6D, a removal step of removing the outer substrate 202 from the deposition substrate 208 from the inner substrate 60 on which the scintillator layer 36 is deposited is performed.
Specifically, the adhesive 106 is peeled off and the outer substrate 202 is removed by pouring a release agent RE for the adhesive 106 such as a liquid containing alcohol into the plurality of holes 204 from the outer substrate 202.

5. Acquisition of Radiation Detector 200 Through the above steps, the radiation detector 200 as shown in FIG. 6E can be acquired. The obtained radiation detector 200 can be incorporated into the electronic cassette 10 in place of the radiation detector 20 described in the first embodiment.

-Action-
According to the method of manufacturing the radiation detector 200 according to the second embodiment of the present invention, the outer substrate 202 can be easily removed from the deposition substrate 208 by pouring the release agent RE from the outer substrate 202. In addition, the selectivity of the outer substrate 202 can be expanded because the outer substrate 202 does not need to be transparent as compared with the first embodiment.

(Modification)
Although the present invention has been described in detail with respect to specific first and second embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art. For example, the above-described plurality of embodiments can be implemented in combination as appropriate. Moreover, you may combine the following modifications suitably.

For example, in the first embodiment, the housing 16 includes a radiation detector 20 that detects the radiation X that has passed through the patient 14 from the irradiation surface 18 side of the housing 16 that is irradiated with the radiation X, and a control board. Although the case where 22 is provided in order has been described, in order from the irradiation surface 18 side where the radiation X is irradiated, the grid and the radiation detector 20 that remove scattered radiation of the radiation X caused by passing through the patient 14. , And a lead plate that absorbs backscattered radiation X may be accommodated.

In the first embodiment, the case where the shape of the housing 16 is a rectangular flat plate has been described. However, the case 16 is not particularly limited, and for example, the front view may be a square or a circle.

Moreover, although 1st Embodiment demonstrated the case where the control board 22 was formed by one, this invention is not limited to this embodiment, Even if the control board 22 is divided into several for every function. Good. Furthermore, although the case where the control board 22 is arranged side by side in the vertical direction (thickness direction of the housing 16) with the radiation detector 20 has been described, it may be arranged side by side with the radiation detector 20 in the horizontal direction. .

In the first and second embodiments, when the inner substrate 60 is not made of aluminum, an aluminum reflecting plate is pasted on the

deposition substrates

104 and 208, and the scintillator layer 36 is formed on the reflecting plate. It may be deposited. In this case, the TFT substrate 30 can receive more light emitted from the scintillator layer 36 than in the case where there is no reflector.

In the electronic cassette 10 of the first embodiment, the case where the radiation X is irradiated from the front side to which the scintillator layer 36 of the radiation detector 20 is bonded, that is, the so-called surface irradiation has been described, but the scintillator layer of the radiation detector 20 is described. Irradiation from the back surface side to which 36 is not bonded, so-called back surface irradiation may be performed. Further, in this case, since the radiation X is irradiated to the scintillator layer 36 without passing through the inner substrate 60, the inner substrate 60 can be cut after the removing step. Thereby, the curvature of the radiation detector 20 can further be suppressed. A similar method can be performed in the second embodiment.

Further, in the first embodiment, the case where the adhesive 102 is peeled off by the ultraviolet ray UV and the adhesive 204 is peeled off by the release agent RE in the second embodiment has been described, but the thermoplastic adhesive may be peeled off by heat. In this case, the adhesive material is preferably a material that peels off at a temperature higher than the vapor deposition temperature of the scintillator layer 36.
Moreover, although the case where the outer side board | substrate 100 and the inner side board | substrate 60 were adhere | attached with the adhesive agent 102 was demonstrated, you may adhere | attach with the double-sided tape, for example, it is not adhere | attached, and is simply overlaid. Just be fine.

In the first embodiment, the case where the deposition substrate 104 is configured by the two

substrates

100 and 60 laminated is described. However, the deposition substrate 104 may be configured by a plurality of three or more substrates. Note that the second embodiment can have the same configuration.

Further, although the case where the scintillator layer 36 has a structure including a plurality of columnar crystals has been described, as long as the

deposition substrates

104 and 208 are used, the scintillator layer 36 may have another structure.

In addition, the

radiation detectors

20 and 200 have been described as completed products after the

outer substrates

100 and 202 have been removed. However, the

radiation detectors

20 and 200 include the

outer substrates

100 and 202 as finished products. When the user who purchased the product is incorporated into the electronic cassette 10, the above removal step may be performed.

In the first embodiment, it is assumed that the front surface irradiation is performed. However, in the case where the above-described back surface irradiation is assumed, the removal step as illustrated in FIG. 5D and the like can be omitted. That is, the outer substrate 100 can be left as it is. The reason is that in the case of surface irradiation, it is necessary to remove the outer substrate 100 to avoid radiation absorption by the outer substrate 100 and to make the radiation reach the scintillator layer 36 side in order to improve the image quality. This is because there is no need to consider radiation absorption by the outer substrate 100 in the case of backside illumination. In this case, the weight of the scintillator layer 36 can be supported together with the outer substrate 100 as well as the inner substrate 60. When the outer substrate 100 is left as described above, the outer substrate 100 may be used as an indicator (control substrate 22) for the signal detection circuit 48 and the scan signal control circuit 50. In this configuration, when one of the radiation detector 20 or the signal detection circuit 48 and the scan signal control circuit 50 is damaged, the rest can be reused by separating from the indicator and replacing only the damaged one. it can.
In the second embodiment as well, the removal step can be omitted in the case of backside illumination.

Further, in the attaching step of the first embodiment, as shown in FIG. 5C, the case where the TFT substrate 30 is attached to the scintillator layer 36 using the adhesive 106 has been described, but an adhesive tape is used instead of the adhesive 106. It may be used. At this time, the adhesive tape has a three-layer structure in the order of the first adhesive, the core material, and the second adhesive, the first adhesive is disposed on the inner substrate 60 side, and the second adhesive is the first adhesive. It is also possible to dispose it on the outer substrate 100 side with an adhesive force higher than that of the adhesive. With such a configuration, when the outer substrate 100 is removed, the adhesive tape does not adhere to the radiation detector 20 (inner substrate 60), and problems such as interference with radiation absorption do not occur. From the same point of view, the first adhesive can be formed in an uneven shape and disposed on the inner substrate 60 side.
Further, the adhesive 106 and the adhesive of the adhesive tape may be applied to only a part of the scintillator layer 36 or the TFT substrate 30 instead of the entire surface.

The entire disclosure of Japanese Application 2010-150207 is incorporated herein by reference.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Reference numeral 10 denotes an electronic cassette.
Reference numeral 20 denotes a radiation detector.
Reference numeral 30 denotes a TFT substrate (light detection substrate).
Reference numeral 36 denotes a scintillator layer.
Reference numeral 60 denotes a substrate (inner substrate).
Reference numeral 100 denotes a substrate (outer substrate).
Reference numeral 102 denotes an adhesive.
Reference numeral 104 denotes a deposition substrate (substrate).
Reference numeral 106 denotes an adhesive.
Reference numeral 200 denotes a radiation detector.
Reference numeral 202 denotes a substrate (outer substrate).
Reference numeral 204 denotes a hole.
Reference numeral 206 denotes an adhesive.
Reference numeral 208 denotes a deposition substrate (substrate).
Reference sign RE is a release agent.
The symbol UV is ultraviolet light.
The symbol X is radiation.

Claims

A deposition step of depositing a scintillator layer that converts incident radiation into light on a plurality of stacked substrates;
Affixing a light detection substrate for converting light emitted from the scintillator layer into an electrical signal on the scintillator layer;
Removing the outer substrate from the substrate on which the scintillator layer is deposited;
A method for manufacturing a radiation detector.
The laminated substrates are bonded to each other with an adhesive,
The manufacturing method of the radiation detector of Claim 1.
The stacked substrates are two pieces,
The outer substrate is transparent;
The adhesive is peelable by ultraviolet rays,
In the removing step, the substrate is removed by irradiating ultraviolet rays from the outer substrate side.
The manufacturing method of the radiation detector of Claim 2.
The stacked substrates are two pieces,
The outer substrate is provided with a hole penetrating the substrate,
In the removing step, the substrate is removed by pouring a release agent from the outer substrate into the hole.
The manufacturing method of the radiation detector of Claim 2.
The method of manufacturing a radiation detector according to any one of claims 1 to 4, wherein, after the removing step, a cut is made in the inner substrate.
In the deposition step, the scintillator layer including a plurality of columnar crystals is deposited by a vapor deposition method.
The method for manufacturing a radiation detector according to any one of claims 1 to 5.
A plurality of stacked substrates;
A scintillator layer deposited on the substrate and converting incident radiation into light;
A photodetecting substrate that is attached to the scintillator layer and converts light emitted from the scintillator layer into electric charge;
A radiation detector comprising:
The plurality of stacked substrates are bonded to each other with an adhesive,
The radiation detector according to claim 7.
The plurality of stacked substrates are two pieces,
The outer substrate is transparent;
The adhesive can be peeled off by ultraviolet rays that pass through the outer substrate.
The radiation detector according to claim 8.
The plurality of stacked substrates are two pieces,
The outer substrate is provided with a hole penetrating the substrate,
The adhesive is peelable by a release agent that has passed through the hole,
The radiation detector according to claim 8.
The scintillator layer is configured to include a plurality of columnar crystals.
The radiation detector according to any one of claims 7 to 10.