JP2012200373A - Radiographic apparatus and its manufacturing method - Google Patents

Abstract

An object of the present invention is to prevent generation of stress on a support substrate due to shrinkage of a sealing agent.
A first sealant 46 is filled on the outer periphery of a bonding surface of a sensor panel 23 and a scintillator panel 24 so as not to contact a support substrate 33 of the scintillator panel 24. In addition, a second seal having a smaller shrinkage rate during curing than the first sealant 46 is provided outside the first sealant 46 between the flange-shaped portion 33a of the support substrate 33 and the sensor panel 23. Agent 47 is filled. To prevent the sealant from flowing on the upper surface of the sensor panel 23 so that the sealant can be filled without a gap in the back of the narrow region sandwiched between the flange 33a and the sensor panel 23. A first flow stop portion 48 and a second flow stop portion 49 are provided.
[Selection] Figure 3

Description

  The present invention relates to a radiation imaging apparatus and a manufacturing method including a scintillator that converts irradiated radiation into light and a sensor panel that detects light converted by the scintillator, and more specifically, a sealant around the scintillator. The present invention relates to a radiographic apparatus and a manufacturing method that are sealed by the above.

  Taking a radiation image represented by the irradiated radiation using a radiation detector of an indirect conversion system that includes a scintillator that converts the irradiated radiation into light and a sensor panel that detects the light converted by the scintillator Radiation imaging devices that can be used have been put into practical use.

  Some scintillators constitute a scintillator layer composed of a plurality of columnar crystals by vapor-depositing cesium iodide (hereinafter referred to as CsI) or the like. In a scintillator composed of columnar crystals, light generated in the columnar crystals travels in the columnar crystals due to the light guide effect of the columnar crystals, and scattering of light emitted from the scintillators is suppressed, so the irradiated radiation is imaged. , It is possible to suppress a decrease in the sharpness of the image. A sensor panel is a sensor substrate made of glass or the like, on which a photosensor having TFT (Thin Film Transistor) active matrix circuits and PD (Photodiode) pixels arranged in a matrix is provided and is emitted from a scintillator. The detected light is detected by an optical sensor.

  The indirect conversion type radiation detector includes a direct vapor deposition method in which a scintillator is vapor-deposited on a sensor panel, and a bonding method in which a scintillator panel in which a scintillator is vapor-deposited on a support substrate is bonded to a sensor panel (for example, see Patent Document 1). ) In the scintillator composed of columnar crystals, the layer at the initial stage of vapor deposition is not sufficiently columnar crystallized. For this reason, the bonding method in which the columnar crystallized tip portion of the scintillator is bonded to the sensor panel has higher image quality than the direct evaporation method in which the initial layer of deposition is close to the sensor panel.

  As shown in FIG. 11, the bonding type radiation detector 19 uses a metal plate (for example, an Al substrate) or the like as the support substrate 33 in consideration of heat resistance when the scintillator 34 is deposited. is there. Further, when the scintillator 34 is vapor deposited on the support substrate 33, the outer periphery of the support substrate 33 is supported by a frame-shaped jig, or a vapor deposition mask that regulates the vapor deposition range of the scintillator 34 is used. Some have a hook-shaped portion 33 a projecting outward from the outer periphery of the scintillator 34.

  Since the scintillator 34 made of CsI or the like has deliquescent properties, it is covered with a protective film 35 having moisture resistance. However, since the radiographic apparatus is difficult to replace even when the scintillator 34 is deliquescent, a sealing structure with higher sealing performance is required. For example, since both surfaces of the scintillator 34 are sandwiched between the support substrate 33 and the sensor panel 23 in the bonding type scintillator panel 24, the sealing effect is obtained by sealing the outer periphery of the scintillator 34 with the sealing portion 28. High sealing structure can be obtained. Patent Document 2 discloses a first sealing resin that seals the outer periphery of the scintillator, and a second sealing resin that covers the electrode extraction portion of the sensor panel and is in contact with the first sealing resin. A radiation detection apparatus is disclosed.

JP 2006-335887 A JP 2005-156545 A

  In the radiation detector 19 having the above-described configuration, the end of the scintillator 34 may be peeled off from the sensor panel 23. When the peeling of the end of the scintillator 34 reaches the effective detection area of the optical sensor 43 of the sensor panel 23, a black dot-like image defect 101 appears on the edge of the radiation image 100 as shown in FIG.

  When the cause of the peeling of the end of the scintillator 34 was investigated, it was found that the cause was shrinkage at the time of curing of the sealing portion 28. For example, when an ultraviolet curable acrylic resin is used as the sealing portion 28, the sealing portion 28 contracts when being cured by being irradiated with ultraviolet rays, and pulls the flange portion 33 a of the support substrate 33 to be elastic. It will be deformed. It was found that stress was generated in the support substrate 33 due to elastic deformation of the hook-shaped portion 33a, and the end portion of the scintillator 34 was peeled off from the sensor panel 23 due to the reaction of this stress.

  In order to solve the above problem, it is conceivable to seal the sealing agent so as not to contact the support substrate as in Patent Document 1, but compared to the case where the sealing agent is filled so as to contact the support substrate. The moisture-proof ability will be reduced. Moreover, even if it uses 2 types of sealing agents like patent document 2, the effect with respect to the stress suppression of a support substrate is not acquired.

  In order to solve the above problems, an object of the present invention is to prevent generation of stress on a support substrate due to shrinkage of a sealing agent.

  In order to solve the above-mentioned problems, a radiation imaging apparatus of the present invention includes a scintillator panel that includes a scintillator that converts radiation into light, and a support substrate that supports the scintillator and has a hook-shaped portion that protrudes outside the scintillator. A sensor panel that detects light converted by the scintillator, a sensor panel that is bonded to the scintillator, a first sealing agent that seals an outer periphery of a surface where the scintillator and the sensor panel are bonded, And a second sealant that is filled between the shape part and the sensor panel and seals the outer periphery of the scintillator.

  Note that the first sealant is preferably not in contact with the support substrate. Moreover, when the 1st sealing agent contacts a support substrate, it is preferable that the contact width is 0.5 mm or less.

  The shrinkage rate of the second sealant is preferably about 20 to 40% of the shrinkage rate of the first sealant. As the first sealant that satisfies such conditions, for example, an ultraviolet curable acrylic resin can be used. Moreover, as a 2nd sealing agent, an epoxy resin can be used, for example.

  The first sealing agent and the second sealing agent may be the same resin with different filler filling rates. In this case, it is preferable that the filler filling rate of the second sealing agent is higher than the filler filling rate of the first sealing agent.

  In the case where the scintillator is composed of a plurality of columnar crystals erected from the support substrate toward the sensor panel, it is preferable that the tip side of the columnar crystals is sealed with the first sealant. In addition, the present invention can be used in a configuration in which the sensor panel is disposed on the radiation irradiation side of the scintillator panel and the scintillator is irradiated with radiation that has passed through the sensor panel.

  The manufacturing method of the radiation imaging apparatus of the present invention includes a step of bonding a scintillator provided on a support substrate and converting radiation into light, and a sensor panel including an optical sensor that detects light converted by the scintillator; A step of sealing the outer periphery of the surface on which the scintillator and the sensor panel are bonded together with a first sealant, a step of curing the first sealant, and a hook-like portion of the support substrate that protrudes to the outside of the scintillator Filling the second sealant with a smaller shrinkage than the first sealant between the sensor and the sensor panel to seal the outer periphery of the scintillator, and curing the second sealant And a step of causing the The first sealant is preferably not in contact with the support substrate. Moreover, when the 1st sealing agent contacts a support substrate, it is preferable that the contact width is 0.5 mm or less.

  You may provide the 1st flow stop part which prevents the flow of a 1st sealing agent in the bonding surface with respect to the scintillator of a sensor panel. Moreover, you may provide the 2nd flow stop part which blocks | prevents the flow of a 2nd sealing agent in the bonding surface of a sensor panel. It is preferable that the heights of the first flow stop portion and the second flow stop portion are 50 μm or more.

  Further, when the height of the first and second flow stop portions is 50 μm or less, the first flow stop portion and the second flow stop portion, the first sealant, and the second The contact angle with the sealant is preferably 50 degrees or more.

  According to the present invention, the shrinkage during curing of the first sealant does not affect the support substrate, and the shrinkage rate of the second sealant is smaller than that of the first sealant. No great stress is generated on the substrate. Therefore, it is possible to prevent the scintillator from being peeled off from the sensor panel due to the stress generated in the support substrate.

It is a perspective view which shows a radiation imaging device partially broken. It is a schematic sectional drawing of a radiography apparatus. It is edge part sectional drawing of a radiation detector. It is sectional drawing which shows the bonding process of a sensor panel and a scintillator panel. It is a top view of a sensor panel. It is sectional drawing which showed the structure of the optical sensor typically. It is a block diagram which shows the principal part structure of the electric system of a radiography apparatus. It is a block diagram which shows the principal part structure of the electrical system of a console and a radiation generator. It is edge part side sectional drawing of the radiation detector which made the 1st sealing agent contact the hook-shaped part. It is the sensor panel top view which abbreviate | omitted the flow stop part partially. It is an edge part sectional side view of the conventional radiation detector. It is an image figure which shows an example of a radiographic image.

  As shown in FIG. 1, a radiation imaging apparatus 10 according to the present invention includes a housing 12 whose overall shape is approximately box-shaped and whose rectangular upper surface is a radiation irradiation surface 11. The casing 12 is made of a material that transmits radiation, and the portion other than the top plate 13 provided with the irradiation surface 11 is made of, for example, ABS resin, and the top plate 13 is made of, for example, carbon. Thereby, the intensity | strength of the top plate 13 is ensured, suppressing the absorption of the radiation by the top plate 13. FIG. The casing 12 has the same size as a conventional cassette having a configuration for recording an image on a photosensitive material by radiation, and can be used in place of the cassette.

  The irradiation surface 11 of the radiation imaging apparatus 10 includes a plurality of LEDs, and displays the operation mode (for example, “ready state” and “data transmitting”) of the radiation imaging apparatus 10 and the operation state such as the remaining capacity of the battery. A display unit 16 is provided. In addition, the display part 16 may be comprised by light emitting elements other than LED, and may be comprised by display means, such as a liquid crystal display and an organic EL display. Further, the display unit 16 may be provided at a site other than the irradiation surface 11.

  A panel-shaped radiation detector 19 is disposed in the housing 12 of the radiation imaging apparatus 10 so as to detect radiation transmitted through the body of the subject so as to face the irradiation surface 11. Further, inside the housing 12, a case for housing various electronic circuits including a microcomputer and a rechargeable and detachable battery (secondary battery) on one end side along the short side of the irradiation surface 11. 20 is arranged. Various electronic circuits of the radiation imaging apparatus 10 including the radiation detector 19 are operated by electric power supplied from a battery accommodated in the case 20. A radiation shielding member made of a lead plate or the like is provided on the irradiation surface 11 side of the case 20 in the housing 12 in order to avoid damage to various electronic circuits accommodated in the case 20 due to radiation irradiation. It is arranged.

  The radiation detector 19 has a configuration in which a sensor panel 23, a scintillator panel 24, and a reinforcing plate 25 are stacked from the irradiation surface 11 side along the direction in which radiation is irradiated. As shown in FIG. 2, the sensor panel 23 and the scintillator panel 24 and the scintillator panel 24 and the reinforcing plate 25 are bonded to each other by a first adhesive layer 26 and a second adhesive layer 27. ing. A sealing portion 28 that protects the scintillator from moisture or the like is provided on the outer periphery of the scintillator panel 24. The sensor panel 23 is attached to the inner surface of the top plate 13 with an adhesive over the entire surface. A control board 29 is disposed on the bottom surface in the housing 12. The control board 29 and the sensor panel 23 are electrically connected via a flexible cable 30.

  FIG. 3 is a cross-sectional view of the edge side of the radiation detector 19, and shows a state in which the top and bottom are inverted with respect to FIG. The scintillator panel 24 includes a support substrate 33, a scintillator 34 provided on the support substrate 33 by vapor deposition, and a protective film 35 that covers the outer periphery of the support substrate 33 and the scintillator 34. Between the support substrate 33 and the scintillator 34, a scintillator underlayer 36 for improving the adhesion between the support substrate 33 and the scintillator 34 is provided.

  The scintillator 34 passes through the body of the subject and is irradiated onto the irradiation surface 11 of the housing 12, absorbs the radiation irradiated through the top plate 13 and the sensor panel 23, and emits light. In general, as the scintillator, for example, a material such as CsI: Tl (cesium iodide added with thallium)), CsI: Na (sodium-activated cesium iodide), GOS (Gd2O2S: Tb), or the like can be used.

  In this embodiment, as the scintillator 34, CsI: Tl is vapor-deposited on the support substrate 33, thereby forming a columnar crystal region composed of a plurality of columnar crystals 38 on the radiation incident side and the sensor panel 23 side, and on the support substrate 33 side. A non-columnar crystal region composed of the non-columnar crystal 39 is formed. The average diameter of the columnar crystal 38 is approximately uniform along the longitudinal direction of the columnar crystal 38. Further, since the scintillator 34 is formed on the support substrate 33 by vapor deposition, the growth rate of the columnar crystals 38 varies depending on the distance from the vapor deposition source. Therefore, the edge shape of the scintillator 34 is tapered so that the height from the support substrate 33 gradually decreases.

  The light generated by the scintillator 34 travels through the columnar crystal 38 by the light guide effect of the columnar crystal 38 and is emitted to the sensor panel 23. At this time, since diffusion of light emitted to the sensor panel 23 side is suppressed, blurring of the radiation image detected by the radiation imaging apparatus 10 is suppressed. Further, since the light reaching the deep part (non-columnar crystal region) of the scintillator 34 is reflected to the sensor panel 23 side by the non-columnar crystal 39, the amount of light incident on the sensor panel 23 (the light emitted from the scintillator 34). (Detection efficiency) is improved.

When the thickness of the columnar crystal region located on the radiation incident side of the scintillator 34 is t1, and the thickness of the non-columnar crystal region located on the support substrate 33 side of the scintillator 34 is t2, t1 and t2 have the following relationship It is preferable to satisfy the formula (1). The film thickness of the scintillator 34 is, for example, about 650 μm.
0.01 ≦ (t2 / t1) ≦ 0.25 (1)

  When the thickness t1 of the columnar crystal region and the thickness t2 of the non-columnar crystal region satisfy the above relational expression, a region (columnar crystal region) that has high luminous efficiency and prevents light diffusion, and a region that reflects light (noncolumnar shape) The ratio along the thickness direction of the scintillator 34 to the crystal region) is a suitable range. Thereby, the light emission efficiency of the scintillator 34, the detection efficiency of the light emitted by the scintillator 34, and the resolution of the radiation image are improved. In addition, if the thickness t2 of the non-columnar crystal region is too thick, a region with low light emission efficiency increases, leading to a decrease in sensitivity of the radiation imaging apparatus 10. Therefore, (t2 / t1) is 0.02 or more and 0.1 or less. A range is more preferable.

  In the scintillator 34 having the above-described configuration, the CsI filling rate in the columnar crystal formation region in the scintillator 34 has an appropriate range and depends on the thickness of the columnar crystal formation region, for example, about 70 to 85% is optimal. . That is, when the filling rate of CsI becomes too small (for example, less than 70%), the light emission amount of the scintillator 34 is significantly reduced. On the other hand, when the filling rate of CsI becomes too large (for example, higher than 85%), the thickness exceeds a certain thickness. Then, since the adjacent columnar crystals start to come into contact with each other, a phenomenon in which part of the light traveling in the columnar crystals is transferred to other columnar crystals in contact (this phenomenon is also referred to as crosstalk) occurs. The pattern of the amount of light emitted from the scintillator 34 changes with respect to the pattern of the amount of radiation applied to the light source, and the radiation detection accuracy decreases (when the irradiated radiation is detected as an image, the sharpness of the detected image decreases). Is caused. Therefore, in order to ensure the sensitivity and accuracy of radiation detection, it is necessary to provide an appropriate gap between adjacent columnar crystals.

  Since the support substrate 33 is heated at the time of vapor deposition of the scintillator 34, the material is preferably a material having high heat resistance, and from the viewpoint of low cost, for example, a metal such as aluminum is preferable. On the outer edge of the support substrate 33, a hook-shaped portion 33 a that protrudes outside the scintillator 34 is provided. This scissor-shaped portion 33a is formed by the scintillator 34 by a region where the scintillator 34 is not deposited to hold the support substrate 33 when CsI or the like is deposited on the support substrate 33, or by a deposition mask that regulates the deposition range of the scintillator 34. This is a region that has not been vapor-deposited, and refers to the range from the bonding surface of the scintillator 34 to the sensor panel 23 to the end of the support substrate 33. The thickness of the support substrate 33 is, for example, about 500 μm when aluminum is used as the material. In addition, in order to make it difficult for the support substrate 33 to warp in the longitudinal direction, the support substrate 33 may be configured so that the rolling direction is along the longitudinal direction.

  For the protective film 35 and the scintillator underlayer 36, a material having a barrier property against moisture in the atmosphere is used, and for example, an organic film obtained by gas phase polymerization such as a thermal CVD method or a plasma CVD method is used. As the organic film, a gas phase polymerized film formed by a thermal CVD method of a polyparaxylene resin or a plasma polymerized film of a fluorine-containing unsaturated hydrocarbon monomer is used. In addition, a laminated structure of an organic film and an inorganic film can be used. As a material of the inorganic film, for example, a silicon nitride (SiNx) film, a silicon oxide (SiOx) film, a silicon oxynitride (SiOxNy) film, Al2O3, or the like is preferable. It is. In order to improve the adhesion between the protective film 35 and the first adhesive layer 26, the protective film 35 may be subjected to atmospheric pressure plasma treatment.

  The sensor panel 23 detects light emitted from the light emission side of the scintillator 34, and is attached to the sensor substrate 42 having a flat plate shape and a rectangular outer shape in plan view, and the scintillator 34 of the sensor substrate 42. And an optical sensor 43 provided on the mating surfaces. The effective detection area 43a (see FIG. 4) capable of properly detecting the light of the optical sensor 43 is more than the surface of the scintillator 34 bonded to the sensor panel 23 so that the light emitted by the scintillator 34 can be reliably detected. It has been made smaller. A glass substrate having heat resistance is used for the sensor substrate 42 in order to form a photodiode (PD: PhotoDiode) constituting the optical sensor 43 by vapor deposition of amorphous silicon, for example. The thickness of the sensor substrate 42 is, for example, about 700 μm.

  In this embodiment, the sensor panel 23 is arranged on the radiation irradiation surface side of the scintillator panel 24. However, the method of arranging the scintillator and the sensor panel in such a positional relationship is “surface reading method (ISS: Irradiation Side Sampling). Since the scintillator emits light more strongly on the radiation incident side, the surface reading method (ISS) in which the light detection unit is arranged on the radiation incident side of the scintillator is arranged on the side opposite to the radiation incident side of the scintillator by “backside reading”. Since the light detection unit and the light emission position of the scintillator are closer than the system (PSS: Penetration Side Sampling), the resolution of the radiation image obtained by imaging is high, and the amount of light received by the light detection unit is increased. As a result, the sensitivity of the radiographic apparatus is improved.

  The sensor panel 23 and the scintillator panel 24 are bonded together by a first adhesive layer 26. Further, an aluminum plate is used for the support substrate 33 of the scintillator panel 24, and a glass substrate is used for the sensor substrate 42 of the sensor panel 23. Furthermore, since the radiation detector 19 becomes high temperature during its operation, the support substrate 33 and the sensor substrate 42 are thermally expanded. Aluminum and glass have a thermal expansion coefficient of about 30 PPM, whereas glass has a large thermal expansion coefficient of about 3 PPM. Therefore, the conventional radiation detector is warped, or the scintillator is warped. Sometimes peeled off from the sensor panel. In the present embodiment, the reinforcing plate 25 is bonded to the support substrate 33 in order to prevent the radiation detector 19 from warping due to a difference in thermal expansion coefficient between the support substrate 33 and the sensor substrate 42.

  The reinforcing plate 25 is preferably made of a material having a thermal expansion coefficient comparable to that of the sensor substrate 42 and having an appropriate rigidity. For example, a carbon substrate is suitable. As the carbon substrate used as the reinforcing plate 25, it is preferable to use a carbon substrate using pitch-based carbon fibers having a high hardness per unit volume. Further, as shown in FIG. 1, since the radiation detector 19 is rectangular, warpage tends to occur in the longitudinal direction. Therefore, in order to suppress warping in the longitudinal direction of the radiation detector 19, it is preferable that the carbon substrate has a fiber direction of the carbon fiber along the longitudinal direction. Furthermore, from the balance between rigidity and weight of the reinforcing plate 25, the thickness of the carbon substrate is preferably, for example, 5 mm or less, and more preferably 0.5 mm or more and 5 mm or less.

  For the first adhesive layer 26 to which the sensor panel 23 and the scintillator 34 are bonded together, an adhesive that maintains elasticity even after bonding is used instead of a curable adhesive. According to this, it is possible to prevent the scintillator 34 from peeling from the sensor panel 23 by absorbing or dispersing the stress due to the difference in thermal expansion coefficient between the support substrate 33 and the sensor substrate 42 by the first adhesive layer 26. . Further, the first adhesive layer 26 made of an adhesive is plastically deformed and bonded together in accordance with the unevenness of the surfaces of the scintillator 34 and the sensor panel 23, so that a gap is formed on the bonding surface between the scintillator 34 and the sensor panel 23. It is possible to prevent a defect in the radiographic image due to the occurrence of. Furthermore, in this embodiment, since the adhesive sheet previously provided with a constant thickness is used as the first adhesive layer 26, the distance between the scintillator 34 and the sensor panel 23 can be kept constant.

The pressure-sensitive adhesive sheet is preferably a soft material containing a polymer component having a gel fraction of 50% or less. This absorbs or disperses the stress due to the difference in thermal expansion coefficient between the support substrate 33 and the sensor substrate 42 and increases the amount of plastic deformation of the adhesive so as to follow the uneven shape on the surface of the scintillator 34 and the sensor panel 23. Because. Moreover, it is preferable that the glass transition point of an adhesive sheet is 0 degrees C or less, and this is for giving moderate hardness to an adhesive sheet at room temperature, and making handling easy. When the pressure-sensitive adhesive sheet satisfying these conditions is represented by elastic modulus, for example, the storage elastic modulus in an environment of 23 ° C. is 5 × 10 ⁵ Pa to ⁵ × 10 ⁴ Pa, and the loss elastic modulus is 2 × 10 ⁵ Pa. The pressure-sensitive adhesive sheet corresponding to ˜2 × 10 ⁴ Pa corresponds.

  Further, the adhesive force between the pressure-sensitive adhesive sheet and the sensor panel 23 and the adhesive force between the pressure-sensitive adhesive sheet and the scintillator 34 are 50% or more of the value at 23 ° C, respectively. Is preferred. Thereby, since the adhesive force of an adhesive sheet does not fall extremely even if temperature rises, the product durability in a high temperature environment can be improved.

  Furthermore, as an adhesive sheet, it is desirable that a ball tack number is 1-6. The ball tack number represents the degree of stickiness of the so-called adhesive layer, and stickiness increases as the value increases. In the present embodiment, when a bonding error occurs in the bonding process between the sensor panel 23 and the scintillator panel 24, the sensor panel 23 and the scintillator panel 24 are once separated and then bonded again. Therefore, it is preferable to use an adhesive sheet with little stickiness.

  The pressure-sensitive adhesive sheet has a thickness of 15 μm or more and 50 μm or less, more preferably about 30 μm. This is because if the first adhesive layer 26 is too thin, the effects of stress relaxation and unevenness tracking cannot be obtained, and if it is too thick, the sharpness of the radiation image decreases due to radiation absorption by the first adhesive layer 26. . As the above adhesive sheet, an acrylic adhesive sheet is preferable. It is because transparency and adhesive strength are high.

  As with the first adhesive layer 26, an adhesive sheet is used for the second adhesive layer 27 that bonds the support substrate 33 and the reinforcing plate 25 together. Similar to the first adhesive layer 26, the second adhesive layer 27 absorbs or disperses stress due to the difference in thermal expansion coefficient between the support substrate 33 and the reinforcing plate 25, and prevents the scintillator 34 from peeling off from the sensor panel 23. is doing. The thickness of the second adhesive layer 27 is preferably about 50 μm or more and 500 μm or less in consideration of adhesive strength, stress relaxation effect, and the like.

  In addition, you may comprise the adhesive sheet which comprises the 2nd contact bonding layer 27 from the adhesive sheet of the small size of several sheets divided | segmented into the longitudinal direction. According to this, when sticking an adhesive sheet to the support substrate 33, a bubble becomes difficult to remain between the support substrate 33 and an adhesive sheet, and stickability improves. Further, it is possible to relieve stress when the support substrate 33 and the reinforcing plate 25 are bent, and to prevent the scintillator 34 from peeling off.

  The sealing portion 28 includes a first sealing agent 46 and a second sealing agent 47. The first sealant 46 is made of a resin having a high moisture resistance and a relatively high shrinkage rate at the time of curing, and the outer periphery of the surface on which the scintillator 34 and the sensor panel 23 are bonded is in contact with the hook-shaped portion 33a. It is sealed so that it does not. The second sealant 47 is made of a resin having a lower shrinkage rate when cured than the first sealant 46, and is filled between the flange 33a and the sensor panel 23 to seal the outer periphery of the scintillator 34. It has stopped.

  In the conventional radiation detector, only a resin having a relatively high shrinkage rate at the time of curing is used as the sealant for sealing the outer periphery of the scintillator 34, although the moisture resistance is high. Therefore, the flange 33a of the support substrate 33 is pulled and elastically deformed due to the shrinkage of the sealing agent, and the end of the scintillator 34 is peeled off from the sensor panel 23 by the reaction of the stress generated on the support substrate 33 due to this elastic deformation. There was something to do.

  In the present embodiment, the first sealant 46 having a high shrinkage rate is filled so as not to touch the support substrate 33, and the second sealant 47 having a shrinkage rate smaller than that of the first sealant 46 is used. Since the gap between the flange 33a and the sensor panel 23 is sealed, no great stress is generated on the support substrate 33. Therefore, in the radiation detector 19 of this embodiment, it is possible to prevent the scintillator 34 from being peeled off from the sensor panel 23 due to the stress generated on the support substrate 33. Further, the bonding surface side of the scintillator 34 with respect to the sensor panel 23 is the tip side of the columnar crystal 38 and thus is vulnerable to moisture, but this portion can be appropriately moisture-proofed by the first sealant 46 having high moisture resistance. it can. Furthermore, since the outside of the first sealant 46 is sealed with the second sealant 47, the entire scintillator 34 can be appropriately moisture-proof.

  For the first sealant 46, for example, an ultraviolet curable acrylic resin (volume shrinkage of about 5 to 10%) is preferably used. Although the ultraviolet curable acrylic resin has a relatively large volume shrinkage, high moisture resistance can be obtained. Further, the second sealant 47 has a lower moisture shrinkage than the ultraviolet curable acrylic resin, but has a smaller volume shrinkage than the ultraviolet curable acrylic resin, for example, an epoxy resin (volume shrinkage 2%). Is preferred. Thereby, the shrinkage rate of the second sealing agent 47 is about 20 to 40 of the shrinkage rate of the first sealing agent 46.

  Further, the same resin may be used for both the first and second sealing agents 46 and 47, and the shrinkage rate may be made different by changing the filling rate of the filler mixed therein. For example, when an ultraviolet curable acrylic resin is used for the first and second sealing agents 46 and 47, by making the filler filling rate of the second sealing agent 47 higher than that of the first sealing agent 46, The shrinkage rate of the second sealing agent 47 can be made lower than that of the first sealing agent 46.

  Since the first sealing agent 46 and the second sealing agent 47 have different shrinkage rates at the time of curing, they cannot be cured at the same time. When the first sealant 46 and the second sealant 47 are simultaneously cured, a gap is generated between the first sealant 46 and the second sealant 47 due to the difference in shrinkage rate. This is because there is a possibility. Further, in order to obtain sufficient moisture-proof performance, it is necessary to fill the sealant to the back of the space sandwiched between the flange 33a of the support substrate 33 and the sensor panel 23. However, the length of the flange 33a is long. Depending on the wettability of the surface of the hook-shaped part 33a and the viscosity of the sealant, it becomes difficult to properly inject the sealant to the depth of the hook-shaped part 33a.

  Considering these, in the present embodiment, the bonding process of the scintillator panel 24 and the sensor panel 23 is performed in the following procedure. As shown in FIG. 4A, a first flow stop portion 48 disposed on the bonding surface of the sensor panel 23 to the scintillator panel 24 so as to surround the outer periphery of the optical sensor 43, and a first flow stop And a second flow stop portion 49 disposed on the outer periphery of the portion 48. The first and second flow stop portions 48 and 49 are protrusions protruding from the surface of the sensor panel 23, and the first and second sealing members 46 and 47 are filled with the first and second sealing agents 46 and 47. The sealing agents 46 and 47 have a function of preventing the sealants 46 and 47 from flowing out.

  As shown in FIG. 4B, in the next step, the scintillator panel 24 is bonded to the sensor panel 23 by the first adhesive layer 26. As shown in FIG. 5C, in the next step, the first sealant 46 is placed on the outer periphery of the bonding surface of the scintillator 34 and the sensor panel 23 so as not to touch the flange 33a of the support substrate 33. Is filled. The first sealant 46 has fluidity, but since the flow is prevented by the first flow stop portion 48, the first sealant 46 can be appropriately filled.

  The first sealing agent 46 filled in the outer periphery of the scintillator 34 is cured by irradiation with ultraviolet rays. The ultraviolet curable acrylic resin constituting the first sealant 46 shrinks in volume when cured, but the first sealant 46 does not touch the hook-shaped portion 33a, so that stress is generated in the support substrate 33. Never do.

  As shown in FIG. 4D, in the next step, the second sealing agent 47 is filled between the flange-shaped portion 33a of the support substrate 33 and the sensor panel. The second sealing agent 47 has fluidity like the first sealing agent 46, but its flow is blocked by the second flow stop portion 49, so that it can be appropriately filled.

  The second sealing agent 47 filled in the outer periphery of the scintillator 34 is cured in the same manner as the first sealing agent 46. When an epoxy resin is used for the second sealant 47, the second sealant 47 is cured by heating. Thus, since the first sealing agent 46 and the second sealing agent 47 having different shrinkage rates are separately cured, the first sealing agent 46 and the second sealing agent 47 are interposed between them. There is no void due to the difference in shrinkage rate. Further, although the volume shrinks even when the second sealing agent 47 is cured, the shrinkage rate is smaller than that of the first sealing agent 46, so that no great stress is generated on the support substrate 33.

  The first and second flow stop portions 48 and 49 need to bear a sealing structure together with the first and second sealing agents 46 and 47 and do not affect the optical sensor 43 of the sensor panel 23. Therefore, it is preferable to use a material having moisture resistance and insulating properties.

  For example, when using a moisture-proof insulating agent (for example, Hitachi Chemical, TE-4200, etc.) as the first and second flow stop portions 48 and 49, the wettability of the surface of the moisture-proof insulating material, the sealing agent Considering the viscosity and the like, the height of the first and second flow stop portions 48 and 49 is preferably 50 μm or more, more preferably 100 μm or more, for example, about 200 μm. In addition, as the first and second flow stop portions 48 and 49, for example, an acrylic adhesive tape (for example, Nitto Denko, N-380, etc.) may be used. In this case, considering the wettability between the adhesive tape and the ultraviolet curable acrylic resin used as the sealant, the height of the first and second flow stop portions 48 and 49 is preferably about 80 μm.

  Further, depending on the wettability of the first and second flow stop portions 48 and 49 with respect to the sealant, the height of the first and second flow stop portions 48 and 49 can be 50 μm or less. In this case, the first and second flow stop portions 48, 49 and the sealant may have a contact angle of 50 degrees or more, more preferably 80 or more depending on the material. 49 must be formed.

  Next, the optical sensor 43 of the sensor panel 23 will be described. As shown in FIG. 6, the optical sensor 43 includes a photoelectric conversion unit 55 including a photodiode (PD: PhotoDiode), a thin film transistor (TFT) 56, and a pixel unit 58 including a storage capacitor 57. A plurality of pixel portions 58 are formed in a matrix on the sensor substrate 42. Further, a planarizing layer 59 for flattening the sensor substrate 42 is formed on the surface of the sensor panel 23 opposite to the radiation arrival direction. As described above, the sensor panel 23 is attached to the top plate 13 by the adhesive layer 60.

  The photoelectric conversion unit 55 is configured such that a photoelectric conversion film 55c that absorbs light emitted from the scintillator 34 and generates charges according to the absorbed light is disposed between the lower electrode 55a and the upper electrode 55b. Yes. The lower electrode 55a is preferably made of a conductive material that is transparent to at least the emission wavelength of the scintillator 34 because the light emitted from the scintillator 34 needs to be incident on the photoelectric conversion film 55c. It is preferable to use a transparent conductive oxide (TCO) that has a high transmittance for visible light and a small resistance value.

  Although a metal thin film such as Au can be used as the lower electrode 55a, TCO is preferable because it tends to increase the resistance value if an optical transmittance of 90% or more is obtained. For example, ITO, IZO, AZO, FTO, SnO2, TiO2, and ZnO2 are preferably used, and ITO is most preferable from the viewpoints of process simplicity, low resistance, and transparency. Note that the lower electrode 55a may have a single configuration common to all the pixel portions, or may be divided for each pixel portion.

  The material constituting the photoelectric conversion film 55c may be any material that absorbs light and generates charges, and for example, amorphous silicon, an organic photoelectric conversion material, or the like can be used. When the photoelectric conversion film 55c is composed of amorphous silicon, the light emitted from the scintillator 34 can be configured to absorb over a wide wavelength range. Since formation of the photoelectric conversion film 55c made of amorphous silicon requires vapor deposition, it is preferable to use a heat-resistant glass substrate for the sensor substrate 42.

  In the TFT 56, a gate electrode, a gate insulating film, and an active layer (channel layer) are stacked, and a source electrode and a drain electrode are formed on the active layer at a predetermined interval. The active layer can be formed of any one of, for example, amorphous silicon, amorphous oxide, organic semiconductor material, carbon nanotube, etc., but the material capable of forming the active layer is not limited to these. .

  As shown in FIG. 7, the optical sensor 43 includes a plurality of gate wirings 63 extending along a certain direction (row direction) for turning on / off individual TFTs 56, and a direction (column) intersecting the certain direction. And a plurality of data wirings for reading out charges accumulated in the storage capacitor 57 (and between the lower electrode 55a and the upper electrode 55b of the photoelectric conversion unit 55) via the on-state TFT 56. 64 is provided.

  Individual gate lines 63 of the sensor panel 23 are connected to a gate line driver 67, and individual data lines 64 are connected to a signal processing unit 68. When radiation that has passed through the subject's body (radiation carrying image information of the subject's body) is irradiated onto the radiation imaging apparatus 10, the scintillator 34 starts from the portion corresponding to each position on the irradiation surface 11. The amount of light corresponding to the radiation dose at each position is emitted, and the photoelectric conversion unit 55 of each pixel unit 58 corresponds to the amount of light emitted from the corresponding part of the scintillator 34. A charge having a magnitude is generated, and this charge is stored in the storage capacitor 57 of each pixel unit 58 (and between the lower electrode 55a and the upper electrode 55b of the photoelectric conversion unit 55).

  When charges are accumulated in the storage capacitors 57 of the individual pixel portions 58 as described above, the TFTs 56 of the individual pixel portions 58 are row-wise by signals supplied from the gate line driver 67 via the gate wiring 63. The charges stored in the storage capacitor 57 of the pixel unit 58 that is sequentially turned on and the TFT 56 is turned on are transmitted through the data wiring 64 as an analog electric signal and input to the signal processing unit 68. Accordingly, the charges accumulated in the storage capacitors 57 of the individual pixel portions 58 are read out in units of rows.

  The signal processing unit 68 includes an amplifier and a sample hold circuit provided for each individual data line 64, and an electric signal transmitted through each data line 64 is amplified by the amplifier and then held in the sample and hold circuit. The In addition, a multiplexer and an A / D (analog / digital) converter are connected in order to the output side of the sample and hold circuit, and the electrical signals held in the individual sample and hold circuits are sequentially (serially) input to the multiplexer. The digital image data is converted by an A / D converter.

  An image memory 71 is connected to the signal processing unit 68, and image data output from the A / D converter of the signal processing unit 68 is sequentially stored in the image memory 71. The image memory 71 has a storage capacity capable of storing image data for a plurality of frames, and image data obtained by imaging is sequentially stored in the image memory 71 every time a radiographic image is captured.

  The image memory 71 is connected to a control unit 73 that controls the overall operation of the radiation imaging apparatus 10. The control unit 73 includes a microcomputer, and includes a CPU 73a, a memory 73b including a ROM and a RAM, a nonvolatile storage unit 73c including an HDD (Hard Disk Drive), a flash memory, and the like.

  In addition, a wireless communication unit 75 is connected to the control unit 73. The wireless communication unit 75 corresponds to a wireless local area network (LAN) standard represented by IEEE (Institute of Electrical and Electronics Engineers) 802.11a / b / g / n, etc. Control the transmission of various information between them. The control unit 73 can wirelessly communicate with the console 79 (see FIG. 8) via the wireless communication unit 75, and can transmit and receive various types of information to and from the console 79.

  The radiation imaging apparatus 10 is provided with a power supply unit 76, and the various electronic circuits (gate line driver 67, signal processing unit 68, image memory 71, wireless communication unit 75, control unit 73, etc.) described above are power supply units. Are connected to each other (not shown), and are operated by electric power supplied from the power supply unit 76. The power supply unit 76 incorporates the above-described battery (secondary battery) so as not to impair the portability of the radiation imaging apparatus 10, and supplies power from the charged battery to various electronic circuits. The gate line driver 67, the signal processing unit 68, the image memory 71, the control unit 73, the wireless communication unit 75, and the power supply unit 76 are provided in the case 20 or the control board 29 described above.

  As shown in FIG. 8, the console 79 is a computer, and includes a CPU 80 that controls the operation of the entire apparatus, a ROM 81 that stores various programs including a control program in advance, a RAM 82 that temporarily stores various data, and various data. Are connected to each other via a bus. In addition, a communication I / F unit 84 and a wireless communication unit 85 are connected to the bus, a display 86 is connected through a display driver 87, and an operation panel 88 is connected through an operation input detection unit 89. .

  The communication I / F unit 84 is connected to the radiation generation apparatus 92 via the connection terminal 84 a, the communication cable 91, and the connection terminal 92 a of the radiation generation apparatus 92. The console 79 (the CPU 80) transmits / receives various information such as an exposure condition to / from the radiation generating apparatus 92 via the communication I / F unit 84. The wireless communication unit 85 has a function of performing wireless communication with the wireless communication unit 75 of the radiation imaging apparatus 10, and the console 79 (the CPU 80 thereof) transmits and receives various types of information such as image data to and from the radiation imaging apparatus 10. This is performed via the wireless communication unit 85. The display driver 87 generates and outputs signals for displaying various information on the display 86, and the console 79 (the CPU 80 of the console 79) displays an operation menu, a captured radiographic image, and the like on the display 86 via the display driver 87. Display. The operation panel 88 includes a plurality of keys, and various information and operation instructions are input thereto. The operation input detection unit 89 detects an operation on the operation panel 88 and notifies the CPU 80 of the detection result.

  The radiation generator 92 includes a communication I / F unit 95 that transmits and receives various information such as an exposure condition between the radiation source 94 and the console 79, and an exposure condition received from the console 79. Includes a tube voltage and tube current information), and a radiation source control unit 96 that controls the radiation source 94.

  Next, the operation of this embodiment will be described. When taking a radiographic image using the radiation imaging apparatus 10, a photographer (for example, a radiographer or the like) orients the irradiation surface 11 side upward between the imaging target part of the subject and the imaging table. The radiation imaging apparatus 10 is inserted, and preparatory work for adjusting the orientation, position, and the like is performed.

  When the preparatory work is completed, the photographer operates the operation panel 88 to instruct the start of photographing. As a result, the console 79 transmits an instruction signal instructing the start of exposure to the radiation generator 92, and the radiation generator 92 emits radiation from the radiation source 94. The radiation emitted from the radiation source 94 is transmitted through the body of the subject to be irradiated on the irradiation surface 11 of the radiation imaging apparatus 10, is transmitted through the top plate 13 and the sensor panel 23, and the irradiation / light emission surface of the scintillator 34. Is irradiated. The scintillator 34 absorbs radiation applied to the irradiation / light emission surface, and emits light having a light amount corresponding to the absorbed radiation amount.

  The sensor panel 23 detects the light emitted to the pixel unit 58 as an image, and stores the image data in the image memory 71. The CPU 73 a transmits the image data stored in the image memory 71 to the console 79 via the wireless communication unit 75. The CPU 80 of the console 79 stores the image data received from the radiation imaging apparatus 10 in the HDD 83 via the RAM 82. Further, the CPU 80 causes the display 86 to display a radiation image composed of image data stored in the HDD 83 via the display driver 87.

  In the radiation imaging apparatus 10, the first sealant 46 and the second sealant 47 contract during curing, but the first sealant 46 having a high contraction rate is not in contact with the support substrate 33. Since the contraction rate of the second sealing agent 47 is smaller than that of the first sealing agent 46, no great stress is generated on the support substrate 33. Therefore, the scintillator 34 does not peel from the sensor panel 23 due to the stress generated in the support substrate 33. Further, the tip side of the columnar crystal 38 that is vulnerable to moisture is sealed with a first sealant 46 having high moisture resistance, and the non-columnar crystal 39 side that is relatively resistant to moisture is sealed with a second sealant 47. Therefore, the entire scintillator 34 can be appropriately moisture-proof.

  In the above embodiment, the first sealant 46 seals the outer periphery of the scintillator 34 so as not to contact the flange-shaped portion 33a. However, as shown in FIG. As long as the contraction does not apply stress to the support substrate 33, the first sealing agent 46 may be in contact with the flange 33 a. According to this, since the entire outer periphery of the scintillator 34 can be sealed with the first sealant 46 having high moisture resistance, the sealing ability is improved. The contact width between the first sealant 46 and the hook-shaped portion 33a is preferably 0.5 mm or less, for example, when an ultraviolet curable acrylic resin is used for the first sealant 46. In addition, since this contact width changes also with the length of the hook-shaped part 33a, the thickness of the support substrate 33, etc., it is not limited to 0.5 mm or less.

  Moreover, in the said embodiment, although the 2nd flow stop part 49 was used with the 1st flow stop part 48, when there is not much difficulty in filling with a sealing agent, a 2nd flow stop part 49, or both the first flow stop 48 and the second flow stop 49 may be omitted.

  Moreover, in the said embodiment, although the 1st and 2nd flow stop parts 48 and 49 are provided over the perimeter of the sensor panel 23, for example, as shown in FIG. When using the sensor panel 23 in which the optical sensor 43 is disposed so as to be close to each other and the flexible cable 30 connected to the control board 29 is pulled out from the remaining two sides of the sensor board 42, the edge of the sensor board 42 is used. Since the flow of the sealant can be prevented by this, only the flow stop portion on the side where the optical sensor 43 is close may be omitted.

  Moreover, in the said embodiment, although the photoelectric converting film 55c of the photoelectric conversion part 55 was comprised with the amorphous silicon, you may comprise the photoelectric converting film 55c with the material containing an organic photoelectric converting material. In this case, an absorption spectrum showing high absorption mainly in the visible light region is obtained, and almost no absorption of electromagnetic waves other than light emitted from the scintillator 34 by the photoelectric conversion film 55c is eliminated, so that radiation such as X-rays and γ-rays is not generated. Noise generated by being absorbed by the photoelectric conversion film 55c can be suppressed. The photoelectric conversion film 55c made of an organic photoelectric conversion material can be formed by attaching an organic photoelectric conversion material on the sensor substrate 42 using a droplet discharge head such as an inkjet head. Heat resistance is not required. For this reason, a sensor substrate made of a material other than glass can be used.

  When the photoelectric conversion film 55c is made of an organic photoelectric conversion material, the radiation is hardly absorbed by the photoelectric conversion film 55c. Therefore, in the surface reading method (ISS) in which the sensor panel 23 is arranged so that the radiation is transmitted, the sensor panel 23 Attenuation of radiation due to passing through can be suppressed, and a decrease in sensitivity to radiation can be suppressed. Therefore, it is particularly suitable for the surface reading method (ISS) to configure the photoelectric conversion film 55c with an organic photoelectric conversion material.

  The organic photoelectric conversion material constituting the photoelectric conversion film 55c is preferably as the absorption peak wavelength is closer to the emission peak wavelength of the scintillator 34 in order to absorb the light emitted from the scintillator 34 most efficiently. Ideally, the absorption peak wavelength of the organic photoelectric conversion material matches the emission peak wavelength of the scintillator 34, but if the difference between the two is small, the light emitted from the scintillator 34 can be sufficiently absorbed. . Specifically, the difference between the absorption peak wavelength of the organic photoelectric conversion material and the emission peak wavelength with respect to the radiation of the scintillator 34 is preferably within 10 nm, and more preferably within 5 nm.

  Examples of organic photoelectric conversion materials that can satisfy such conditions include quinacridone-based organic compounds and phthalocyanine-based organic compounds. For example, since the absorption peak wavelength in the visible region of quinacridone is 560 nm, if quinacridone is used as the organic photoelectric conversion material and CsI (Tl) is used as the material of the scintillator 34, the difference in peak wavelength can be made within 5 nm. Thus, the amount of charge generated in the photoelectric conversion film 55c can be substantially maximized.

  The photoelectric conversion film 55c applicable to the radiation detection panel will be specifically described. The electromagnetic wave absorption / photoelectric conversion site in the radiation detection panel is an organic layer including electrodes 55a and 55b and a photoelectric conversion film 55c sandwiched between the electrodes 55a and 55b. More specifically, this organic layer is a part that absorbs electromagnetic waves, a photoelectric conversion part, an electron transport part, a hole transport part, an electron blocking part, a hole blocking part, a crystallization preventing part, an electrode, and an interlayer contact. It can be formed by stacking or mixing improved parts.

  The organic layer preferably contains an organic p-type compound or an organic n-type compound. The organic p-type semiconductor (compound) is a donor organic semiconductor (compound) mainly represented by a hole transporting organic compound, and is an organic compound having a property of easily donating electrons. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Accordingly, any organic compound having an electron donating property can be used as the donor organic compound. The organic n-type semiconductor (compound) is an acceptor organic semiconductor (compound) mainly represented by an electron transporting organic compound, and is an organic compound having a property of easily accepting electrons. More specifically, the organic compound having the higher electron affinity when two organic compounds are used in contact with each other. Therefore, any organic compound can be used as the acceptor organic compound as long as it is an organic compound having an electron accepting property.

  Since the materials applicable as the organic p-type semiconductor and the organic n-type semiconductor and the configuration of the photoelectric conversion film 55c are described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

  The photoelectric conversion unit 55 only needs to include at least the electrode pairs 55a and 55b and the photoelectric conversion film 55c. In order to suppress an increase in dark current, at least one of an electron blocking film and a hole blocking film is provided. It is preferable to provide both.

  The electron blocking film can be provided between the upper electrode 55b and the photoelectric conversion film 55c. When a bias voltage is applied between the upper electrode 55b and the lower electrode 55a, the electron blocking film is applied from the upper electrode 55b to the photoelectric conversion film 55c. An increase in dark current due to injection of electrons can be suppressed. An electron donating organic material can be used for the electron blocking film. The material actually used for the electron blocking film may be selected according to the material of the adjacent electrode, the material of the adjacent photoelectric conversion film 55c, etc., and the electron function is 1.3 eV or more from the work function (Wf) of the adjacent electrode material. A material having a large affinity (Ea) and an Ip equivalent to or smaller than the ionization potential (Ip) of the material of the adjacent photoelectric conversion film 55c is preferable. Since the material applicable as the electron donating organic material is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

  The thickness of the electron blocking film is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, and particularly preferably, in order to surely exhibit the dark current suppressing effect and prevent a decrease in the photoelectric conversion efficiency of the photoelectric conversion unit 55. It is 50 nm or more and 100 nm or less.

  The hole blocking film can be provided between the photoelectric conversion film 55c and the lower electrode 55a, and when a bias voltage is applied between the upper electrode 55b and the lower electrode 55a, the lower electrode 55a to the photoelectric conversion film 55c. It is possible to suppress the increase of dark current due to injection of holes into the substrate. An electron-accepting organic material can be used for the hole blocking film. The material actually used for the hole blocking film may be selected according to the material of the adjacent electrode, the material of the adjacent photoelectric conversion film 55c, etc., and 1.3 eV or more from the work function (Wf) of the material of the adjacent electrode. A material having a large ionization potential (Ip) and an Ea equivalent to or larger than the electron affinity (Ea) of the material of the adjacent photoelectric conversion film 55c is preferable. Since the material applicable as the electron-accepting organic material is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

  The thickness of the hole blocking film is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, particularly preferably, in order to surely exhibit the dark current suppressing effect and prevent a decrease in the photoelectric conversion efficiency of the photoelectric conversion unit 55. Is from 50 nm to 100 nm.

  In the case where the bias voltage is set such that holes move to the lower electrode 55a and electrons move to the upper electrode 55b among the charges generated in the photoelectric conversion film 55c, the electron blocking film and the hole blocking film are used. It is sufficient to reverse the position of. Moreover, it is not essential to provide both the electron blocking film and the hole blocking film, and if any of them is provided, a certain degree of dark current suppressing effect can be obtained.

  Further, as the amorphous oxide capable of forming the active layer of the TFT 56, for example, an oxide containing at least one of In, Ga, and Zn (for example, In—O system) is preferable, and In, Ga, and Zn are preferable. Of these, oxides containing at least two of them (for example, In—Zn—O, In—Ga—O, and Ga—Zn—O) are more preferable, and oxides including In, Ga, and Zn are particularly preferable. As the In—Ga—Zn—O-based amorphous oxide, an amorphous oxide whose composition in a crystalline state is represented by InGaO 3 (ZnO) m (m is a natural number of less than 6) is preferable, and InGaZnO 4 is particularly preferable. More preferred. Note that the amorphous oxide capable of forming the active layer is not limited to these.

  Examples of the organic semiconductor material capable of forming an active layer include, but are not limited to, phthalocyanine compounds, pentacene, vanadyl phthalocyanine, and the like. In addition, about the structure of a phthalocyanine compound, since it demonstrates in detail by Unexamined-Japanese-Patent No. 2009-212389, description is abbreviate | omitted.

  If the active layer of the TFT 56 is formed of any one of an amorphous oxide, an organic semiconductor material, a carbon nanotube, etc., radiation such as X-rays is not absorbed or even if it is absorbed, a very small amount remains. Can be effectively suppressed.

  Further, when the active layer is formed of carbon nanotubes, the switching speed of the TFT 56 can be increased, and the degree of light absorption in the visible light region in the TFT 56 can be reduced. In addition, when the active layer is formed of carbon nanotubes, the performance of the TFT 56 is remarkably deteriorated just by mixing a very small amount of metallic impurities into the active layer. Therefore, the highly pure carbon nanotubes are separated and extracted by centrifugation or the like. Therefore, it must be used for forming the active layer.

  In addition, since the film | membrane formed with the organic photoelectric conversion material and the film | membrane formed with the organic-semiconductor material have sufficient flexibility, the photoelectric conversion film 55c formed with the organic photoelectric conversion material, and an active layer are made into organic. If the TFT 56 formed of a semiconductor material is combined, it is not always necessary to increase the rigidity of the sensor panel 23 in which the weight of the patient's body is added as a load.

  In addition, the sensor substrate 42 may be any substrate that has optical transparency and little radiation absorption. Here, both the amorphous oxide constituting the active layer of the TFT 56 and the organic photoelectric conversion material constituting the photoelectric conversion film 55 c of the photoelectric conversion unit 55 can be formed at a low temperature. Therefore, the sensor substrate 42 is not limited to a substrate having high heat resistance such as a semiconductor substrate, a quartz substrate, and a glass substrate, and a flexible substrate made of synthetic resin, aramid, or bionanofiber can also be used. Specifically, flexible materials such as polyesters such as polyethylene terephthalate, polybutylene phthalate, polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, poly (chlorotrifluoroethylene), etc. A conductive substrate can be used. By using such a flexible substrate made of synthetic resin, it is possible to reduce the weight, which is advantageous for carrying around, for example. The sensor substrate 42 includes an insulating layer for ensuring insulation, a gas barrier layer for preventing permeation of moisture and oxygen, an undercoat layer for improving flatness or adhesion to electrodes, and the like. It may be provided.

  Since aramid can be applied at a high temperature process of 200 ° C. or more, the transparent electrode material can be cured at a high temperature to reduce the resistance, and can be applied to automatic mounting of a driver IC including a solder reflow process. Moreover, since aramid has a thermal expansion coefficient close to that of ITO (indium tin oxide) or a glass substrate, there is little warping after manufacturing and it is difficult to break. In addition, aramid can make a substrate thinner than a glass substrate or the like. The sensor substrate 42 may be formed by laminating an ultrathin glass substrate and aramid.

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 an acrylic resin or an epoxy resin in bacterial cellulose, a bio-nanofiber having a light transmittance of about 90% at a wavelength of 500 nm can be obtained while containing 60 to 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. The sensor substrate 42 can be thinned.

  When a glass substrate is used as the sensor substrate 42, the thickness of the entire sensor panel 23 is, for example, about 0.7 mm. By using a thin substrate made of a synthetic resin having light transmittance as the sensor substrate 42, The thickness of the entire sensor panel 23 can be reduced to, for example, about 0.1 mm, and the sensor panel 23 can be flexible. Further, by providing the sensor panel 23 with flexibility, the impact resistance of the radiation imaging apparatus 10 is improved, and even when an impact is applied to the radiation imaging apparatus 10, it is difficult to be damaged. In addition, plastic resin, aramid, bio-nanofiber, etc. all absorb little radiation, and when the sensor substrate 42 is formed of these materials, the amount of radiation absorbed by the sensor substrate 42 is also reduced. ), Even if the sensor panel 23 is configured to transmit radiation, it is possible to suppress a decrease in sensitivity to radiation.

  In the above embodiment, the ISS type radiation detection apparatus has been described as an example. However, the present invention can also be applied to a PSS type radiation detection apparatus. In addition, although the example in which the radiation detector is incorporated in the cassette-size housing has been described, it is also possible to incorporate the radiation detector in a standing type or a standing type imaging apparatus or a mammography apparatus. In addition, it is needless to say that the configuration of the radiation imaging apparatus according to the present invention described in the above embodiment is an example, and can be appropriately changed without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Radiography apparatus 19 Radiation detector 23 Sensor panel 24 Scintillator panel 25 Reinforcement board 26 1st adhesion layer 27 2nd adhesion layer 28 Sealing part 33 Support substrate 33a Saddle-shaped part 34 Scintillator 42 Sensor board 43 Optical sensor 46 1st 1 sealant 47 second sealant 48 first flow stop portion 49 second flow stop portion

Claims (16)

A scintillator panel comprising: a scintillator that converts radiation into light; and a support substrate that supports the scintillator and has a hook-shaped portion projecting outside the scintillator;
A sensor panel that detects the light converted by the scintillator and is bonded to the scintillator;
A first sealant that seals the outer periphery of the surface on which the scintillator and the sensor panel are bonded;
A second sealant that is filled between the bowl-shaped portion and the sensor panel and seals the outer periphery of the scintillator,
The radiation imaging apparatus according to claim 2, wherein the second sealant has a smaller shrinkage rate during curing than the first sealant.   The radiographic apparatus according to claim 1, wherein the first sealant is not in contact with the support substrate.   The radiation imaging apparatus according to claim 1, wherein a contact width between the first sealant and the support substrate is 0.5 mm or less.   The radiographic apparatus according to claim 1, wherein a contraction rate of the second sealant is about 20 to 40% of a contraction rate of the first sealant.   The radiation imaging apparatus according to claim 4, wherein the first sealant is an ultraviolet curable acrylic resin, and the second sealant is an epoxy resin.   The radiographic apparatus according to claim 1, wherein the first sealant and the second sealant are the same resin having different filler filling rates.   The radiographic apparatus according to claim 6, wherein a filler filling rate of the second sealant is higher than a filler filling rate of the first sealant.   The scintillator is composed of a plurality of columnar crystals standing from the support substrate toward the sensor panel, and a tip side of the columnar crystals is sealed with the first sealant. Item 8. The radiographic apparatus according to any one of Items 1 to 7.   The radiographic imaging according to claim 1, wherein the sensor panel is disposed on a radiation irradiation side of the scintillator panel, and the scintillator is irradiated with radiation transmitted through the sensor panel. apparatus. A step of bonding a scintillator provided on a support substrate for converting radiation into light and a sensor panel including an optical sensor for detecting light converted by the scintillator;
Sealing the outer periphery of the surface where the scintillator and the sensor panel are bonded together with a first sealant;
Curing the first sealant;
Filling the sensor panel with a second sealant having a smaller shrinkage rate at the time of curing than the first sealant, between the flange portion of the support substrate and the sensor panel projecting outside the scintillator. Sealing the outer periphery of the scintillator;
And a step of curing the second sealant. A method of manufacturing a radiation imaging apparatus, comprising:   The method of manufacturing a radiation imaging apparatus according to claim 10, wherein the first sealant is not in contact with the support substrate.   The method for manufacturing a radiation imaging apparatus according to claim 10, wherein a contact width between the first sealant and the support substrate is 0.5 mm or less.   13. The method according to claim 10, further comprising a step of providing a first flow stop portion that prevents the flow of the first sealant on a bonding surface of the sensor panel to the scintillator. A method for manufacturing a radiation imaging apparatus.   The method for manufacturing a radiation imaging apparatus according to claim 13, further comprising a step of providing a second flow stop portion for preventing the flow of the second sealant on the bonding surface of the sensor panel.   The method of manufacturing a radiation imaging apparatus according to claim 14, wherein heights of the first flow stop portion and the second flow stop portion are 50 μm or more.   The heights of the first and second flow stop portions are 50 μm or less, the first flow stop portion and the second flow stop portion, and the first sealant. The method of manufacturing a radiation imaging apparatus according to claim 14, wherein a contact angle with the second sealant is 50 degrees or more.

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