JP6114635B2 - Radiation detector and manufacturing method thereof - Google Patents

Description

  Embodiments generally relate to radiation detectors and methods of manufacturing the same.

  A planar X-ray detector using an active matrix has been developed as a new generation X-ray diagnostic detector. By detecting the X-rays irradiated to the X-ray detector, an X-ray image or a real-time X-ray image is output as a digital signal. In this X-ray detector, X-rays are converted into visible light, that is, fluorescence by a scintillator layer, and this fluorescence is converted into signal charges by a photoelectric conversion element such as an amorphous silicon (a-Si) photodiode or CCD (Charge Coupled Device). By acquiring the image.

As a material of the scintillator layer, cesium iodide (CsI): sodium (Na), cesium iodide (CsI): thallium (Tl), sodium iodide (NaI), or gadolinium oxysulfide (Gd ₂ O) is generally used. ₂ S) or the like is used. The scintillator layer can improve resolution characteristics by forming grooves by dicing or the like, or by depositing by a vapor deposition method so that a columnar structure is formed. There are various scintillator materials as described above, and they are properly used depending on the application and necessary characteristics.

  A reflective film may be formed on the upper surface of the scintillator layer in order to improve the use efficiency of fluorescence and improve sensitivity characteristics. That is, of the fluorescence emitted from the scintillator layer, the fluorescence directed to the opposite side of the photoelectric conversion element is reflected by the reflection film, and the fluorescence reaching the photoelectric conversion element side is increased.

For the reflective film, a metal layer with high fluorescence reflectance such as silver alloy or aluminum is formed on the scintillator layer, or a light-scattering reflective film made of a light-scattering substance such as TiO ₂ and a binder resin is applied. It is formed by a forming method or the like. In addition, a method of reflecting scintillator light by bringing a reflector having a metal surface such as aluminum into close contact with the scintillator layer instead of forming on the scintillator layer has been put into practical use.

  A moisture-proof structure for protecting a scintillator layer and a reflective layer (or a reflective plate, etc.) from the external atmosphere to suppress deterioration of characteristics due to humidity is an important component for making a detector a practical product. In particular, when a CsI: Tl film or a CsI: Na film, which is a material having a large deterioration with respect to humidity, is used as a scintillator layer, high moisture-proof performance is required.

  As the moisture-proof structure, there is a method using a CVD film of polyparaxylylene (hereinafter abbreviated as parylene), or a structure in which the periphery of the scintillator is enclosed by a surrounding member and sealed in combination with a moisture-proof layer. As a structure capable of obtaining a higher moisture proof performance, a structure in which an aluminum foil or the like having excellent moisture proof performance is processed into a hat shape including a scintillator layer and its buttock is bonded and sealed to a substrate is known. In this moisture-proof structure, when a sealing material with an inorganic filler added to the adhesive layer is used, it is possible to obtain further superior moisture-proof performance.

US Pat. No. 6,262,422 JP-A-5-242847 Japanese Patent No. 4764407 JP 2009-128023 A JP 2012-037454 A

  A moisture-proof structure that uses a moisture-proof body such as a hat that includes a scintillator layer to bond and seal the buttock of the moisture-proof body and the substrate is markedly superior to other methods in that it can ensure high moisture-proof performance. Is superior to. In this moisture-proof structure, in order to ensure sufficient stability of the sealing between the flange portion of the moisture-proof body, such as a hat shape, and the substrate, and to ensure high reliability, between the flange portion of the moisture-proof body and the substrate. It is important to increase the applied amount of the intervening adhesive sufficiently and to increase the applied pressure for bringing the collar portion and the substrate into close contact with each other.

  However, if these two conditions are satisfied, the adhesive inevitably protrudes from the damp part of the moisture-proof body, and a surplus adhesive layer protrudes (spreads) on the substrate around the damp part. Will do. When this adhesive layer protrudes to the electrode connection tab pad (TAB Pad) formed on the peripheral substrate of the moisture-proof structure, the FPC (flexible printed circuit board) can be connected to the pad. Disappear.

  In order to avoid such a problem, it is necessary to provide a certain distance or more between the outer end of the flange portion of the moisture-proof body and the pad for electrode connection (TAB or the like). Considering the positional deviation of the moisture-proof body and the substrate (for example, about ± 1 mm) and the protrusion width of the adhesive (for example, about 3 mm at the maximum) and connecting the outer edge of the collar of the moisture-proof body to the electrode ( For example, a design that secures an interval of the pad portion of TAB or the like of 4 mm or more is necessary. If the pad part for electrode connection (TAB, etc.) is on both sides on the signal line side (generally X-TAB) and the control line side (generally Y-TAB), for example, the dimensions are 8 mm in length and width respectively. Is required.

  The dimensions required for the perimeter of the moisture barrier increase the external dimensions of the radiation detector with respect to the same effective pixel area and the area size of the scintillator layer formed thereon, so that the compact design as a radiation detector can be achieved. Will interfere. In addition, an excessive increase in the overall dimensions of the radiation detector also increases the weight of the detector. This is a serious demerit especially in portable radiation detectors that require a light weight and compact design.

  In order to prevent the adhesive layer from sticking out, it is possible to reduce the amount of adhesive applied or to reduce the pressure adhesion, but in that case the adhesive seal between the moisture-proof body and the substrate is not sufficient. It tends to be insufficient, and it tends to cause problems in the reliability of the bonded part in a high-temperature and high-humidity test or a cold environment.

  Therefore, an object of the embodiment is to reduce the size of the radiation detector while maintaining the reliability of the moisture-proof structure.

In order to achieve the above-described object, according to an embodiment, in a method of manufacturing a radiation detector, an array substrate forming step of forming an array substrate in which photoelectric conversion elements are two-dimensionally arranged on a substrate, and the photoelectric of the array substrate forming a scintillator layer forming step of converting element forms a scintillator layer for converting a radiation covering the array region to the fluorescence, a moistureproof body comprising a flange portion opposed to the portion surrounding the scintillator layer before SL array substrate a moistureproof body forming step, the adhesive is adhered to the opposite bonding portion and an outer edge the bottom surface in a region protruding outward from the array substrate of the collar portion of the opposing adhesive portions between the array substrate and the flange portion and the collar The collar part with a pressing jig having a frame part formed with a pressure surface facing the surface on the opposite side of the opposing adhesive part of the collar part so as to form a protruding part protruding higher than the part Pressurized, characterized by comprising: a bonding step of bonding the said array substrate and said moistureproof body.

According to the embodiment, in the radiation detector, an array substrate in which photoelectric conversion elements are two-dimensionally arranged on the substrate, and a scintillator for covering the region where the photoelectric conversion elements are arranged on the array substrate and converting the radiation into fluorescence. A moisture-proof body comprising a layer, a metal molded body covering the scintillator layer and having a flange portion facing a portion surrounding the scintillator layer of the array substrate, and opposing adhesion between the flange portion and the array substrate parts and said moistureproof body having a protruding portion protruding higher than the from the outer edge of the flange portion bottom surface in a region protruding outward in close contact with the array substrate the collar portion of the opposing adhesive portions and the array substrate And an adhesive layer for adhering to each other.

It is a typical perspective view of the radiation detection device by one embodiment. It is a circuit diagram of the array board | substrate of the radiation detector by one Embodiment. It is a block diagram of the radiation detection apparatus by one Embodiment. It is a partial expanded sectional view of the cross section of the radiation detector by one Embodiment. It is a top view of the radiation detector by one Embodiment. It is a side view of the radiation detector by one Embodiment. It is an expanded sectional view of the outer periphery part vicinity of the radiation detector by one Embodiment. It is an expanded sectional view of the outer periphery part vicinity of the radiation detector by the modification of one Embodiment. It is a typical sectional view at the time of adhesion of a moisture-proof body and an array substrate by one embodiment. It is a graph which shows the prototype evaluation result of the protrusion width | variety of the contact bonding layer to the outer side of the collar part of a moisture-proof body in the case of changing the application quantity and applied pressure of an adhesive agent in one Embodiment. It is a graph which shows the trial evaluation result of the protrusion height of the adhesive agent to the outer side of the buttocks of the moisture-proof body when the application amount and the applied pressure of the adhesive agent are changed in one embodiment. It is typical sectional drawing at the time of adhesion | attachment of the moisture-proof body and array substrate in a comparative example. It is a graph which shows the trial manufacture evaluation result of the protrusion width | variety of the contact bonding layer to the outer side of the buttocks of a moisture-proof body at the time of changing the application quantity and applied pressure of an adhesive agent in the comparative example of one Embodiment. It is a graph which shows the trial manufacture evaluation result of the protrusion height of the adhesive agent to the outer side of the buttocks of the moisture-proof body when the application amount and the applied pressure of the adhesive agent are changed in the comparative example of the embodiment. It is a table | surface which shows the outline | summary of the evaluation sample of the high-temperature, high-humidity test and the thermal cycle test in one Embodiment and a comparative example. It is a table | surface of the high temperature, high humidity test result in one Embodiment and a comparative example. It is a graph which shows the test result of the resolution characteristic in the high temperature, high humidity test in one Embodiment and a comparative example. It is a table | surface of the cooling reliability test result in one Embodiment and a comparative example. It is a graph which shows the presence or absence of generation | occurrence | production of abnormality in the cooling reliability test in one Embodiment and a comparative example. It is a table | surface which shows the contact bonding layer preparation conditions of the sample by one Embodiment and a modification. It is a table | surface which shows the result of the high temperature, high humidity test of the sample by one Embodiment and a modification. It is a table | surface of the thermal reliability test result of the sample by one Embodiment and a modification. It is a graph which shows the test result of the resolution characteristic in the high temperature, high humidity test of the sample by one Embodiment and a modification. It is a graph which shows the presence or absence of generation | occurrence | production of abnormality in the cooling reliability test of the sample by one Embodiment and a modification.

  FIG. 1 is a schematic perspective view of a radiation detection apparatus according to an embodiment. FIG. 2 is a circuit diagram of the array substrate of the radiation detector according to the present embodiment. FIG. 3 is a block diagram of the radiation detection apparatus according to the present embodiment. FIG. 4 is a partially enlarged sectional view of a section of the radiation detector according to the present embodiment. FIG. 5 is a top view of the radiation detector according to the present embodiment. FIG. 6 is a side view of the radiation detector according to the present embodiment.

  The radiation detector 11 of this embodiment is an X-ray plane sensor that detects an X-ray image that is a radiation image, and is used for general medical applications, for example. The radiation detection apparatus 10 includes the radiation detector 11, a support plate 31, a circuit board 30, and a flexible board 32. The radiation detector 11 has an array substrate 12 and a scintillator layer 13. The radiation detector 11 detects incident X-rays and converts them into fluorescence, and converts the fluorescence into electrical signals. The radiation detection apparatus 10 drives the radiation detector 11 and outputs an electrical signal output from the radiation detector 11 as image information. The image information output by the radiation detection apparatus 10 is displayed on an external display or the like.

  The array substrate 12 is a photoelectric conversion substrate that converts fluorescence into an electrical signal. The array substrate 12 has a glass substrate 16. A plurality of fine pixels 20 are arranged in a square lattice pattern on the surface of the glass substrate 16. The pixels 20 are arranged in a rectangular pixel region (active region) having a diagonal length of 13 inches, for example. Each pixel 20 includes a thin film transistor 22 and a photodiode 21. On the surface of the glass substrate 16, control lines 18 extend between the pixels 20 along rows of a square lattice in which the pixels 20 are arranged. Further, on the surface of the glass substrate 16, the same number of data lines 19 extend between the pixels 20 along a square lattice column in which the pixels 20 are arranged. The scintillator layer 13 is formed on the surface of the region where the pixels 20 of the array substrate 12 are arranged.

  The scintillator layer 13 is provided on the surface of the array substrate 12 having a size of 14 × 17 inches, for example, and generates fluorescence in the visible light region when X-rays enter. The generated fluorescence reaches the surface of the array substrate 12.

The scintillator layer 13 is formed by forming, for example, cesium iodide (CsI): thallium (Tl) or sodium iodide (NaI): thallium (Tl) into a columnar structure by a vacuum deposition method. For example, a vapor deposition film of CsI: Tl is used for the scintillator layer 13, and the film thickness is about 600 μm. The thickness of the pillar (pillar) of the columnar structure crystal of CsI: Tl is, for example, about 8 to 12 μm at the outermost surface. Alternatively, gadolinium oxysulfide (Gd ₂ O ₂ S) phosphor particles are mixed with a binder material, applied onto the array substrate 12, fired and cured, and formed into a square column by forming grooves by dicing with a dicer. Then, the scintillator layer 13 may be formed. Between these columns, air or an inert gas such as nitrogen (N ₂ ) for preventing oxidation may be enclosed, or a vacuum state may be provided.

  The array substrate 12 receives the fluorescence generated in the scintillator layer 13 and generates an electrical signal. As a result, the visible light image generated in the scintillator layer 13 by the incident X-ray is converted into image information expressed by an electrical signal.

  The radiation detector 11 is supported by the support plate 31 so that the surface opposite to the surface on which the scintillator layer 13 is formed and the support plate 31 are in contact with each other. The circuit board 30 is disposed on the opposite side of the support plate 31 with respect to the radiation detector 11. The radiation detector 11 and the circuit board 30 are electrically connected by a flexible board 32.

  Each photodiode 21 is connected to a control line 18 and a data line 19 through a thin film transistor 22 which is a switching element. In addition, a storage capacitor 27 is connected to each photodiode 21 in parallel. The storage capacitor 27 is formed in a rectangular flat plate shape, and is provided opposite to the lower portion of each photodiode 21. The storage capacitor 27 may also serve as the capacitance of the photodiode 21 and is not always necessary.

  The photodiode 21 and the storage capacitor 27 connected in parallel to the photodiode 21 are connected to the drain electrode 25 of the thin film transistor 22. The gate electrode 23 of the thin film transistor 22 is connected to the control line 18. The source electrode 24 of the thin film transistor 22 is connected to the data line 19.

  The gate electrodes 23 of the thin film transistors 22 of the pixels 20 located in the same row of the array are connected to the same control line 18. The source electrodes 24 of the thin film transistors 22 of the pixels 20 located in the same column of the array are connected to the same data line 19.

  The gate electrodes 23 of the thin film transistors 22 in the pixels 20 in the same row are connected to the same control line 18. The source electrodes 24 of the thin film transistors 22 in the pixels 20 in the same column are connected to the same data line 19.

  Each thin film transistor 22 has a switching function for accumulating and discharging charges generated by the incidence of fluorescence on the photodiode 21. The thin film transistor 22 is at least partially composed of a semiconductor material such as amorphous silicon (a-Si) as an amorphous semiconductor, which is a crystalline semiconductor material, or polysilicon (P-Si), which is a polycrystalline semiconductor. Has been.

  In FIGS. 1 and 2, the pixels are described only for 5 rows and 5 columns or 4 rows and 4 columns, but actually, more pixels are formed according to the resolution and the imaging area.

  The radiation detection apparatus 10 includes a radiation detector 11, a gate driver 39, a row selection circuit 35, an integration amplifier 33, an A / D converter 34, a parallel / serial converter 38, and an image synthesis circuit 36. Have. The gate driver 39 is connected to each control line 18 of the radiation detector 11. The gate driver 39 controls the operation state of each thin film transistor 22, that is, on and off. The integrating amplifier 33 is connected to each data line 19 of the radiation detector 11.

  The row selection circuit 35 is connected to the gate driver 39. The parallel / serial converter 38 is connected to the integrating amplifier 33. The A / D converter 34 is connected to a parallel / serial converter 38. The A / D converter 34 is connected to the image composition circuit 36.

  The integrating amplifier 33 is provided on a flexible substrate 32 that connects the radiation detector 11 and the circuit board 30, for example. The other elements are provided on the circuit board 30, for example.

  The gate driver 39 receives a signal from the row selection circuit 35 and controls the operation state of each thin film transistor 22, that is, on and off. That is, the voltage of the control line 18 is changed in order. The gate driver 39 is mounted, for example, near the outer periphery of the surface of the array substrate 12. The row selection circuit 35 sends a signal for selecting a predetermined row for scanning the X-ray image to the gate driver 39. The integrating amplifier 33 amplifies and outputs a very small charge signal output from the radiation detection panel through the data line 19.

  On the surface of the array substrate 12, an insulating protective film 28 that covers detection elements such as the photodiodes 21 and the thin film transistors 22 and metal wirings such as the control lines 18 and the data lines 19 is formed. The scintillator layer 13 is formed on the surface of the protective film 28 so as to cover the region where the pixels 20 are arranged.

  A reflective film 14 is often provided on the surface of the scintillator layer 13. The reflection film 14 reflects the fluorescent light generated in the scintillator layer 13 that moves away from the array substrate 12 to the array substrate 12 side. As a result, the amount of fluorescent light reaching the photodiode 21 increases.

The reflective film 14 is formed by a method of forming a metal having a high fluorescence reflectance such as a silver alloy or aluminum on the scintillator layer. Alternatively, a reflector having a metal surface such as aluminum adhered to the scintillator layer 13 or a diffuse reflective film 14 made of a light scattering material such as TiO ₂ and a binder resin may be applied and formed. Note that the reflective film 14 is not necessarily required due to characteristics such as resolution and luminance required for the radiation detector 11.

  The radiation detector 11 has a moisture-proof structure. This moisture-proof structure is formed by adhering and sealing a moisture-proof body 15 covering the scintillator layer 13 and the reflective film 14 to the surface of the array substrate 12.

  The moisture-proof body 15 is formed in a hat shape with a raised central portion. The peripheral portion of the moisture-proof body 15 is a flat belt-like collar portion 50. The flange portion 50 is formed in a band shape surrounding the outside of the region where the scintillator layer 13 is formed on the surface of the array substrate 12. A top plate portion 51 is formed inside the collar portion 50. The top plate portion 51 is a flat plate portion that is slightly larger than the scintillator layer 13. A slope portion 52 is formed between the flange portion 50 and the top plate portion 51.

  The flange 50 faces the array substrate 12. The flange 50 and the array substrate 12 are bonded. The scintillator layer 13 and the reflective film 14 formed on the array substrate 12 are covered with the top plate portion 51 and the slope portion 52 of the moisture-proof body 15. The moisture-proof body 15 protects the scintillator layer 13 and the reflective film 14 from outside air and humidity.

  The moisture-proof body 15 is formed of, for example, aluminum or an aluminum alloy foil. In this embodiment, the moisture-proof body 15 is formed of 0.1 mm A1N30-O material (annealing material of pure aluminum-based material). The width of the flange 50 is, for example, 2.5 mm.

  On the array substrate 12, pads 29 are arranged with exposed end portions of the control line 18 and the data line 19 to form a terminal group 26. The terminal group 26 is arranged along the side of the array substrate 12. The terminal group 26 connected to the control line 18 and the terminal group 26 connected to the data line 19 are arranged along different sides. These terminal groups 26 are electrically connected to the circuit board 30 via the flexible board 32.

  FIG. 7 is an enlarged cross-sectional view of the vicinity of the outer periphery of the radiation detector according to the present embodiment.

  Lead wires 62 extend from the active area for acquiring the X-ray image of the central portion of the array substrate 12 to the pads 29 arranged in the peripheral portion of the substrate. On the outermost layer of the array substrate 12, an inorganic film of about 0.2 to 0.3 μm and an organic film of about 2 μm are formed as the protective film 28. The lead wiring includes a control line 18 for driving the TFT, a data line 19 for reading out charges corresponding to an X-ray image, and a bias line for applying a bias voltage for operating the photodiode 21.

  The moisture-proof body 15 and the array substrate 12 are bonded by an adhesive layer 90. The adhesive layer 90 has an opposing adhesive portion 91 and a protruding portion 92. The opposing adhesive portion 91 is formed between the flange portion 50 and the array substrate 12. The protruding portion 92 is a portion that protrudes outward from the outer edge of the flange portion 50, that is, in a direction from the outer edge of the flange portion 50 toward the outer edge of the array substrate 12. The protruding portion 92 of the adhesive layer 90 protrudes from the surface of the array substrate 12. In the case of this example, the protruding height of the protruding portion 92 is at least higher than the surface of the flange portion 50 facing the array substrate 12.

  FIG. 8 is an enlarged cross-sectional view of the vicinity of the outer peripheral portion of the radiation detector according to a modification of the present embodiment.

  In this modified example, the protruding portion 92 wraps around the surface of the collar portion 50 opposite to the facing adhesive portion 91. That is, the vicinity of the outer edge of the flange portion 50 is sandwiched between the opposing adhesive portion 91 and the wraparound portion 93.

  Next, the manufacturing method of this radiation detector is demonstrated.

  First, the array substrate 12 is manufactured by forming the pixels 20, the control lines 18, the data lines 19 and the like on the glass substrate 16. Next, the scintillator layer 13 is formed on the surface of the array substrate 12. Further, the moisture-proof body 15 is obtained by press-molding a foil of aluminum or aluminum alloy. Next, the moisture-proof body 15 is bonded to the array substrate 12.

  FIG. 9 is a schematic cross-sectional view of the moisture-proof body and the array substrate according to the present embodiment at the time of bonding.

  An adhesive tray (pressure jig) 80 is used when the moisture-proof body 15 and the array substrate 12 are bonded. The adhesive tray 80 has a frame portion 81 around which the flange portion 50 is placed. A recessed portion 82 is formed inside the frame portion 81. The moisture-proof body 15 is placed on the adhesive tray 80 in a state where the flange portion 50 is placed on the frame portion 81 and the top plate portion 51 and the slope portion 52 are arranged in the recess portion 82.

  The width of the frame portion 81 is substantially the same as the width of the collar portion 50. The size of the recess 82 is substantially the same as the size of the top plate 51 and the slope 52. For this reason, the outer periphery of the moisture-proof body 15 placed on the adhesive tray 80 is disposed so as to substantially overlap the outer periphery of the adhesive tray 80. The widths of the collar part 50 and the frame part 81 are both 2.5 mm, for example. In consideration of the dimensional error of the moisture-proof body 15, the width of the frame portion may be slightly narrower or wider than the width of the heel of the moisture-proof body.

  An adhesive 94 is applied to the surface of the flange portion 50 of the moisture-proof body 15 placed on the adhesive tray 80 and facing the array substrate 12. The adhesive 94 is applied over the entire circumference in a band shape narrower than the width of the flange portion 50 by, for example, a dispenser. The adhesive 94 may be applied with the moisture-proof body 15 placed on the adhesive tray 80, or the moisture-proof body 15 coated with the adhesive 94 may be placed on the adhesive tray.

  In a state where the adhesive 94 is applied to the flange portion 50, the adhesive tray 80 is pressed against the array substrate 12 side to pressurize the flange portion 50 toward the array substrate 12. The application amount of the adhesive 94 is set such that the adhesive 94 protrudes from the outer edge of the flange 50 when the flange 50 is pressed against the array substrate 12 with a predetermined pressure. After attaching the flange 50 to the array substrate 12 via the adhesive 94, the adhesive 94 is cured.

  When pressurizing the moistureproof body 15 to the array substrate 12, the frame portion 81 does not exist at least in the vicinity of the flange portion 50 in the region outside the flange portion 50. That is, there is no structure for suppressing the flow of the adhesive 94 outside the outer edge of the flange portion 50 of the moisture-proof body 15. As a result, the adhesive 94 that protrudes from the outer edge of the flange 50 when the flange 50 is pressed toward the array substrate 12 spreads along the side surface (edge surface) of the adhesive tray 80. Therefore, the spreading of the protruding portion of the adhesive layer 90 to the outside in the surface direction of the array substrate 12 is suppressed to be small, and instead, it is formed in a convex shape in the height direction. In particular, when the moisture-proof body 15 is pressed against the array substrate 12 from vertically downward to vertically upward, that is, when the protruding adhesive 94 hangs down along the side surface of the adhesive tray 80 due to gravity, Spreading of the protruding portion of the agent 94 outward in the surface direction is further suppressed.

  After the radiation detector 11 is completed by forming the moisture-proof structure in this way, connection of the signal processing circuit wiring to the pad 29 of the data line 19, connection of the control circuit wiring to the pad 29 of the control line 18, etc. The radiation detection apparatus 10 is completed through the mounting process, the electrical test for confirming the presence or absence of abnormal connection of the photoelectric conversion element and the pad, the assembly to the housing, the X-ray image test, and the like.

  Next, an example in which the radiation detector 11 of the present embodiment is prototyped will be described.

A CsI: Tl vapor deposition film was used for the scintillator layer 13, the film thickness was about 600 μm, and the columnar structure crystal pillar (pillar) thickness of CsI: Tl was about 8 to 12 μm on the outermost surface. As the scintillator layer 13, a CsI: Tl film (600 μmt) was formed on a substrate corresponding to a size of 14 × 17 inches by a vacuum deposition method. The reflective film 14 was formed by applying and drying a coating liquid obtained by mixing a submicron powder of TiO _2, a binder resin, and a solvent on the scintillator layer 13.

  The moisture-proof body 15 was formed into a hat shape by press-forming AL foil having a thickness of 0.1 mm into a structure having a flange portion having a width of 2.5 mm in the peripheral portion. An adhesive 94 was applied to the flange portion 50 of the hat-shaped moisture-proof body 15 by a dispenser device, and was bonded to the substrate on which the scintillator film 13 and the reflective film 14 were formed. The adhesive 94 was prepared by both a heat curing type and an ultraviolet curing type epoxy material. The specific gravity of the adhesive 94 is about 1.4 g / cc. The application amount of the adhesive 94 to the collar portion 50 of the hat-shaped moisture-proof body 15 is 0.4 mg / mm, 0.6 mg / mm, 0.8 mg / mm, 1.2 mg / mm, 1.6 mg / mm. Prototyped at 5 levels.

  In this trial manufacture, the adhesive tray 80 shown in FIG. 9 was used for the adhesion between the flange portion 50 of the moisture-proof body 15 and the array substrate 12. The adhesive tray 80 is formed so that the width of the frame portion 81 to be pressed at the time of bonding is 2.5 mm substantially matching the width of the flange portion 50 of the moisture-proof body 15. Considering the positional deviation at the time of pasting, even if the frame width is given a margin of, for example, 0.1 to 0.5 mm, and the frame is slightly wider, for example, the width is 2.6 to 3.0 mm. Good.

The pressure conditions at the time of bonding are 0.5 kgf / cm ² , 1.0 kgf / cm ² , 1.5 kgf / cm ² , 2.0 kgf / cm ² , 2 per unit area of the flange portion 50 of the moisture-proof body 15. 5 levels of 5 kgf / cm ² were set.

  The way in which the adhesive layer is crushed, and hence the thickness of the adhesive layer and the amount of protrusion, is determined by the viscosity and the coating amount of the adhesive 94 and the pressure applied at the time of bonding. It is necessary to select an adhesive having a suitable viscosity depending on the required thickness of the adhesive layer and possible manufacturing conditions (application amount and applied pressure). When UV curable adhesive is used, it depends on its viscosity, but after application of the adhesive, it is irradiated with a small amount of UV in advance, and the adhesive is increased in hardness by a certain amount before bonding. Things are also possible. The viscosity of the adhesive used in the trial production is about 400 Pa · sec, which is very high.

  FIG. 10 is a graph showing the results of trial evaluation of the protrusion width of the adhesive layer on the outer side of the buttocks of the moisture-proof body when the application amount and the applied pressure of the adhesive are changed in this embodiment. FIG. 11 is a graph showing the results of trial evaluation of the height of protrusion of the adhesive to the outer side of the buttock of the moisture-proof body when the application amount and the applied pressure of the adhesive are changed in the present embodiment.

  In this embodiment, since there is no structure for suppressing the flow of the adhesive 94 on the outer side of the flange portion 50 of the moisture-proof body, the protruding portion 92 of the adhesive layer 90 formed by curing the adhesive 94 is an adhesive tray. It spreads along the side surface (edge surface) of 80. As a result, the protruding portion 92 of the adhesive layer 90 is restrained from spreading outward in the planar direction, and is instead formed in a convex shape in the height direction.

The protruding width of the protruding portion 92 of the adhesive layer 90 increases as the application amount and the applied pressure increase. However, when the pressing force exceeds approximately 1.0 kgf / cm ² , the increase in the protrusion width accompanying the increase in the pressing force is saturated and becomes almost constant. Further, the protruding height of the protruding portion 92 of the adhesive layer 90 increases as the application amount and the applied pressure increase. However, when the pressing force exceeds approximately 1.0 kgf / cm ² , the increase in the protrusion height with the increase in the pressing force is saturated and becomes almost constant.

  For comparison, we also made a prototype using an adhesive tray with a wide frame.

  FIG. 12 is a schematic cross-sectional view when the moisture-proof body and the array substrate are bonded in the comparative example.

  In this comparative example, the width of the frame portion 85 of the adhesive tray 84 is sufficiently wider than the width of the flange portion 50 of the moisture-proof body 15. In this comparative example, the frame width of the adhesive tray 84 is 20 mm. The size of the recess 86 of the adhesive tray 84 is the same as the size of the recess 82 of the adhesive tray 80 of the embodiment.

  FIG. 13 is a graph showing the results of trial evaluation of the protrusion width of the adhesive layer on the outer side of the buttocks of the moisture-proof body when the application amount and the applied pressure of the adhesive are changed in the comparative example of the present embodiment. FIG. 14 is a graph showing a trial evaluation result of the height of protrusion of the adhesive to the outer side of the buttocks of the moisture-proof body when the application amount and the applied pressure of the adhesive are changed in the comparative example of the present embodiment.

  In this comparative example, the frame portion 85 of the adhesive tray 84 that suppresses the flow of the adhesive 94 in the height direction exists outside the flange portion 50 of the moisture-proof body 15. For this reason, the protruding portion of the adhesive 94 spreads outward in the substrate. Moreover, the gap between the array substrate 12 and the frame portion 85 of the adhesive tray 84 is at most about the thickness of the flange portion 50 of the moisture-proof body 15 (0.1 mm in this comparative example), and a small amount of the adhesive 94 is eaten. Even if it protrudes, the outward spread of the array substrate 12 becomes large.

  Thus, according to the present embodiment, it can be seen that the width of the protruding portion 92 of the adhesive layer 90 is clearly reduced even under the same adhesive application amount and pressure condition. Even if the application amount of the adhesive 94 and the range of the pressurizing conditions are greatly changed, the width of the protruding portion 92 of the adhesive layer 90 is within about 1.5 mm at most. From this result, according to the present embodiment, if the outer periphery of the adhesive layer 90 of the moisture-proof body 15 is 2 to 3 mm, a compact design in which the pads 29 and the like are arranged on the outer side can be realized.

  On the other hand, in the comparative example in which the frame portion 85 of the adhesive tray 84 is widened, the protrusion of the adhesive exceeding 10 mm occurs even in the current examination range depending on the application amount of the adhesive 94 and the pressure condition. In the direction in which the application amount of the adhesive 94 increases and the applied pressure increases, the maximum height of the protruding portion of the adhesive layer does not change so much, and the width of the protruding portion of the adhesive layer becomes significantly large. I understand that. Therefore, it is extremely difficult to control the conditions in order to appropriately secure the width of the adhesive layer and to prevent the seal material from protruding to the surrounding pad portion. When there is a difference in the width of the protruding portion of the adhesive layer in the front, rear, left, and right in this way, there is a difference of 10 mm or more in the dimension to be secured outside the effective pixel area. That is, eliminating the structure for suppressing the flow of the adhesive 94 on the outer side of the flange portion 50 of the moisture-proof body as in this embodiment is clearly superior to the compact design of the radiation detector 11.

  In order to examine the reliability of the moisture-proof structure between the present embodiment and the comparative example, a high-temperature and high-humidity test and a cooling / heating cycle test were performed. These tests were performed in a panel state in which a moisture-proof structure was formed. The high-temperature and high-humidity test and the thermal cycle test are finally confirmed in the state of a product built in the housing, but are basically the same as the results of testing in a panel state where the moisture-proof structure is formed. is there.

  FIG. 15 is a table showing an outline of evaluation samples of the high-temperature and high-humidity test and the thermal cycle test in the present embodiment and the comparative example.

  These evaluation samples for reliability test were prepared using a plain dummy panel in which a pixel pattern composed of photoelectric conversion elements and TFTs was not formed. The glass substrate and the uppermost protective film are equivalent to the actual substrate, and the other films and patterning were omitted. This is because the panel formed up to the moisture-proof structure is suitable for measuring luminance and resolution characteristics. In addition, regarding the moisture-proof reliability and cooling / cooling reliability of the bonded structure portion according to the present embodiment, it is considered that trial evaluation with a dummy panel can be performed in the same manner as an actual substrate.

  FIG. 16 is a table of high-temperature and high-humidity test results in the present embodiment and comparative examples. FIG. 17 is a graph showing test results of resolution characteristics in the high-temperature and high-humidity test in the present embodiment and the comparative example.

  Reliability at high temperature and high humidity was evaluated by following how the luminance and resolution characteristics obtained by the scintillator layer and the reflective film deteriorate with storage time in a 60 ° C.-90% RH environment. FIG. 16 shows the evaluation results of resolution characteristics that are more sensitive to humidity. The resolution characteristics were implemented by a method in which a resolution chart was placed on the front surface side of the sample, and X-rays corresponding to RQA-5 were irradiated to measure 2 Lp / mm CTF (Contrast transfer function) from the back surface side. The maintenance ratio (%) with respect to the storage time of 60 ° C.-90% RH is shown with the initial CTF as 100%.

  As can be seen from the comparison with the table of FIG. 15, it can be seen that the sample with the protrusion of the adhesive layer has a better resolution maintenance ratio at high temperature and high humidity than the sample without protrusion. Also, a sample with a narrow frame adhesive tray with a small protrusion width outside the adhesive layer and a large protrusion height, and a sample with a wide frame adhesive tray with a large protrusion width outside the adhesive layer and a large protrusion height. There is no particular difference between small samples. This feature is that the portion of the adhesive layer 90 that protrudes outside the flange 50 of the moisture-proof body 15 does not particularly affect the moisture-proof performance, and the gap 50 between the moisture-proof body 15 and the array substrate 12 is not affected. This is probably because the moisture-proof performance is regulated by the formed part.

  FIG. 18 is a table of cooling reliability test results in the present embodiment and comparative examples. FIG. 19 is a graph showing presence / absence of occurrence of abnormality in the cooling reliability test in the present embodiment and the comparative example.

  The thermal reliability test was carried out under the temperature condition of (−20 ° C. × 1 h) → (room temperature × 30 minutes) → (60 ° C. × 1 h) → ((room temperature × 30 minutes), and the number of cycles was up to 100 cycles. It was confirmed whether or not there was any abnormality such as peeling or destruction of the adhesive layer in each sample at the lap every 10 cycles in the middle. This is the number of samples, that is, the number of samples in which the sealed state is maintained.

  As can be seen from the comparison with the table of FIG. 15, it can be seen that the sample with the protrusion of the adhesive layer 90 is less likely to be peeled off or broken in the cold test than the sample without the protrusion. . In addition, a sample with a narrow frame adhesive tray 80 and a small protruding width outside the adhesive layer and a large protruding height, and a sample with a wide frame adhesive tray 84 and a large protruding width outside the adhesive layer. There is no particular difference between the sample with a small protrusion height. This feature is that the portion of the adhesive layer 90 that protrudes out of the flange portion 50 of the moisture-proof body 15 does not particularly affect the degree of adhesion and strength of the adhesive layer with respect to changes in cold temperature, and the flange portion of the moisture-proof body 15 This is presumably because the degree of adhesion and the strength against thermal stress are regulated at the portion formed between the substrate 50 and the array substrate 12.

  When the frame portion of the adhesive tray that pressurizes the flange portion 50 of the moisture-proof body 15 is arranged so that the side surface is inside the outer edge of the flange portion of the moisture-proof body 15, the vicinity of the adhesive layer 90 has a shape as shown in FIG. It becomes. Under the condition that the adhesive sufficiently protrudes outward from the flange portion 50 of the moisture-proof body 15, the adhesive layer 90 extends to the surface of the flange portion 50 of the moisture-proof body 15 opposite to the surface facing the array substrate 12. .

  A reliability test was performed on a sample in which the adhesive layer according to the modified example of the present embodiment wraps around the surface opposite to the surface facing the array substrate of the buttocks of the moistureproof body and a comparative example thereof.

  FIG. 20 is a table showing the adhesive layer creation conditions of the sample according to the present embodiment and the modification. FIG. 21 is a table showing the results of the high-temperature and high-humidity test of samples according to this embodiment and the modification. FIG. 22 is a table of the thermal reliability test results of the samples according to this embodiment and the modification. FIG. 23 is a graph showing the test results of the resolution characteristics in the high-temperature and high-humidity test of samples according to this embodiment and the modification. FIG. 24 is a graph showing presence / absence of occurrence of abnormality in the cooling reliability test of samples according to the present embodiment and the modification. In FIG. 24, the vertical axis represents the number of samples in which no abnormality occurs, that is, the sample in which the sealed state is maintained.

  It can be seen that, in the sample having the wraparound of the adhesive layer 90 on the back surface of the flange 50, higher reliability can be ensured particularly in the cooling / heating cycle test as compared with the sample without the wraparound. The reason is considered as follows. That is, a stress in the peeling direction is applied between the flange portion 50 of the moisture-proof body 15 and the adhesive layer 90 due to a difference in thermal expansion between the array substrate 12 and the moisture-proof body 15. However, it is estimated that the structure in which the flange portion 50 of the moisture-proof body 15 is sandwiched by the adhesive layer 90 also from the back surface side has an effect against the peeling stress.

  Adhesive 94 that sticks out after bonding is attached to the frame portion 81 of the adhesive tray 80 and the side wall (edge surface) portion of the frame portion 81, which prevents the moistureproof body 15 and the array substrate 12 from being removed from the adhesive tray 80. There is a case. Therefore, it is preferable that these portions where the adhesive 94 is likely to protrude are previously coated with a material such as a tape of polytetrafluoroethylene (Teflon (registered trademark)) to which the adhesive is difficult to adhere. Alternatively, it is desirable that a material coating (coating) to which the adhesive is difficult to adhere is previously provided.

  Although there are some differences depending on the material of the adhesive 94, the surface energy at room temperature (20 to 25 ° C.), such as polytetrafluoroethylene (Teflon (registered trademark)), silicone resin, polypropylene resin, etc. is generally 30 mN / m or less. If it is made of a material, it is experimentally confirmed that the sticking out of the adhesive 94 is prevented from being firmly fixed to the adhesive tray 80, and no particular problem occurs in removing the array substrate 12 and the moisture-proof body 15 from the adhesive tray 84. It was confirmed. In addition to the method of sticking the tape, it is also effective to coat Teflon (registered trademark) or silicone resin on the adhesive tray 84 in advance. Further, it is possible to preliminarily apply low surface energy oils and fats to the corresponding portion of the adhesive tray 84 to suppress adhesion of the protruding adhesive 94 to the adhesive tray 80.

  The moisture-proof body 15 and the array substrate 12 can be bonded together in a reduced pressure atmosphere. When bonded together in a reduced pressure state, the moisture-proof body 15 is in close contact with the film surface on the array substrate 12, that is, the reflective film 14 on the scintillator layer 13 in this embodiment. As a result, the moisture-proof body 15 does not move on the film surface even when there is vibration or impact, and it is difficult for abnormalities such as image shake due to microphonics to occur. In addition, by observing the adhesion state of the moisture-proof body 15 to the film surface, it is possible to confirm the reduced pressure state inside the moisture-proof body 15 and whether there is a leak portion such as a pinhole in the moisture-proof body 15 or a defect in the adhesive layer 90. Can also be judged. In the unlikely event that a leak occurs, it is possible to avoid leakage to the customer.

  When bonding the moisture-proof body 15 and the array substrate 12 under a reduced pressure atmosphere, when returning the periphery to the atmospheric pressure after bonding, due to the difference between the outer pressure (atmospheric pressure) and the inner pressure of the adhesive layer 90, The adhesive layer 90 receives a force drawn into the moisture-proof body 15. In order to avoid problems such as leakage due to this phenomenon, the hardness, thickness, adhesion width, and adhesion between the array substrate 12 and the moisture-proof body 15 of the adhesive layer 90 can withstand external pressure in a reduced pressure state before returning to atmospheric pressure. It is necessary to secure.

When a cationic polymerization ultraviolet curable adhesive is used, for example, it can be prepared as follows. The width | variety of the collar part 50 of the moisture-proof body 15 shall be 2.5 mm, and the application quantity of the adhesive agent 94 shall be 0.8 mg / mm. After the adhesive is applied, ultraviolet light of 365 nm is irradiated at 80 mJ / cm ² .

Thereafter, the adhesive tray 80 on which the moisture-proof body 15 is placed and the array substrate 12 to which the scintillator film 13 and the reflective film 14 are placed are placed in a vacuum chamber, and the pressure in the chamber is reduced to 0.1 atm. The moisture-proof body 15 and the array substrate 12 are bonded together. Thereafter, the inside of the chamber was returned to atmospheric pressure, and ultraviolet rays were further irradiated from the back surface of the array substrate 12 by about 6 J / cm ² to increase the hardness of the adhesive 94. Furthermore, the curing of the adhesive layer 90 was completed by heat treatment at 60 ° C. for 3 hours.

  A lead wiring 62 that connects the pixel area and the pad 29 to the external electric circuit passes through a portion where the flange portion 50 of the moisture-proof body 15 is bonded to the array substrate 12. For this reason, when the ultraviolet rays are irradiated from the back surface of the array substrate 12, the portion of the lead wiring 62 is not irradiated with the ultraviolet rays. That is, curing is not performed.

  Therefore, a cationic polymerization type ultraviolet curing adhesive may be used. The cationic polymerization type ultraviolet adhesive has a characteristic that the curing reaction generated in the ultraviolet irradiation part continues after the ultraviolet irradiation and also propagates to the peripheral part of the ultraviolet irradiation part. Due to this feature, for example, a portion of the adhesive 94 in the shadow of the lead wiring 62 having a thickness of about 50 μm to 100 μm also propagates the curing reaction of the portion irradiated with the ultraviolet light between the peripheral wirings. The propagation of the reaction is promoted, and a certain hardness can be obtained. For this effect, the metal wiring 62 is provided by ultraviolet irradiation from the back surface of the array substrate 12 while taking advantage of the stability of the viscosity, long pot life, easy handling, etc., which are the characteristics of the ultraviolet curable adhesive. An adhesive layer 90 can be formed in the region.

Although the material of the moistureproof body 15 has been aluminum foil 0.1Mmt, material is not limited to aluminum, aluminum alloys and light metal and _SiO 2 such as a resin and an inorganic film (Al, SiON, ceramic of _Al 2 _{O 3} or _the like A low moisture-permeable moisture-proof material with a laminated structure of (material) can also be used. Also, the thickness is not particularly limited as long as it is not an extreme thickness that absorbs X-rays unnecessarily, and because of its rigidity, no problems occur after bonding to the substrate.

  In FIG. 9, the side surface (edge surface) of the frame portion 81 of the adhesive tray 80 is perpendicular to the pressure surface, but the side surface (edge surface) may be curved or chamfered. . Although the rising shape of the protruding portion 92 of the adhesive layer 90 differs according to these side surface shapes, the adhesive 94 flows so as to have a convex shape upward from the surface of the array substrate 12, and to the outside of the array substrate 12. The spread of is suppressed.

  As described above, according to the present embodiment, the adhesive layer 90 that bonds the array substrate 12 and the flange portion 50 of the moisture-proof body 15 is the opposing adhesive portion between the flange portion 50 of the moisture-proof body 15 and the surface of the array substrate 12. In addition to 91, it is formed on the surface of the array substrate 12 outside the flange 50. Further, the protruding portion 92 that protrudes outward from the flange portion 50 of the adhesive layer 90 is convex upward, and its maximum height exceeds the height of the upper surface of the flange portion 50. When such a radiation detector 11 forms the adhesive layer 90 by pressing the adhesive 94 between the collar portion 50 of the moisture-proof body 15 including the scintillator layer 13 and the array substrate 12 to form the adhesive layer 90, the moisture-proof body The adhesive tray 80 having a frame-like pressure surface is disposed on the back surface side of the surface of the flange portion 15 facing the array substrate 12, and the outer side surface (edge surface) of the pressure surface of the adhesive tray 80 is It exists on the extension of the outer edge of the collar part 50 of the moisture-proof body 15, or the position close | similar to it.

  According to such a radiation detector and the manufacturing method thereof, the amount of the adhesive 94 and the pressure applied at the time of bonding are adjusted, so that sufficient encroachment of the sealing material is ensured up to the outer portion of the hat-shaped moisture-proof body. In addition, the adhesive tray 90 that presses the flange portion 50 of the moisture-proof body 15 at the time of bonding can have a specific shape, so that the spread of the adhesive layer 90 in the outer direction can be minimized. As a result, the flange portion 50 of the moisture-proof body 15 and the array substrate 12 are in close contact with each other in a maximum area, and can surely have high moisture-proof performance and high reliability in a cold / hot environment change or a high-temperature / high-humidity environment. In addition, the possibility of problems due to the spread of the adhesive to the pads 29 and the like disposed around the moisture-proof body 15 is reduced. That is, it is possible to provide a radiation detector that has high reliability with respect to the moisture-proof structure and is compatible with a compact design.

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

DESCRIPTION OF SYMBOLS 10 ... Radiation detection apparatus, 11 ... Radiation detector, 12 ... Array substrate, 13 ... Scintillator layer, 14 ... Reflection film, 15 ... Moisture-proof body, 16 ... Glass substrate, 18 ... Control line, 19 ... Data line, 20 ... Pixel , 21 ... Photodiode, 22 ... Thin film transistor, 23 ... Gate electrode, 24 ... Source electrode, 25 ... Drain electrode, 26 ... Terminal group, 27 ... Storage capacitor, 28 ... Protective film, 29 ... Pad, 30 ... Circuit board, 31 DESCRIPTION OF SYMBOLS ... Support plate, 32 ... Flexible board, 33 ... Integration amplifier, 34 ... A / D converter, 35 ... Row selection circuit, 36 ... Image composition circuit, 38 ... Parallel / serial converter, 39 ... Gate driver, 50 ... 鍔, 51 ... Top plate part, 52 ... Slope part, 62 ... Lead wiring, 80 ... Adhesive tray, 81 ... Frame part, 82 ... Recessed part, 84 ... Adhesive tray, 85 ... Frame part, 86 ... See section, 90 ... adhesive layer, 91 ... facing bonding portion, 92 ... protruding portion, 93 ... curved portion, 94 ... adhesive

Claims (8)

An array substrate forming step of forming an array substrate in which photoelectric conversion elements are two-dimensionally arranged on the substrate;
A scintillator layer forming step of forming a scintillator layer that covers the region where the photoelectric conversion elements of the array substrate are arranged and converts radiation into fluorescence;
A moisture-proof body forming step of forming a moisture-proof body having a collar portion facing a portion surrounding the scintillator layer of the array substrate;
Adhesive facing bonding portion and the outer edge of the flange portion of the opposing adhesive portions bottom in the area protruding outwardly in close contact with the array substrate protrudes higher than the collar portion between the array substrate and the flange portion The moisture-proof portion is pressurized by pressing the collar portion with a pressure jig having a frame portion formed with a pressure surface facing the opposite surface of the opposite adhesive portion of the collar portion so as to form a protruding portion. A bonding step of bonding the body and the array substrate;
The manufacturing method of the radiation detector characterized by comprising.   2. The method of manufacturing a radiation detector according to claim 1, wherein an outer edge of the frame portion is positioned inside an outer edge of the collar portion. The method of manufacturing a radiation detector according to claim 2, wherein the protruding portion is formed so as to wrap around the surface of the flange portion on the opposite side of the opposed adhesive portion.   4. The method of manufacturing a radiation detector according to claim 1, wherein in the bonding step, the moisture-proof body is pressed toward the array substrate from vertically below. 5.   The radiation detection according to any one of claims 1 to 4, wherein a surface of the frame portion that is in contact with the adhesive is coated with a material having a surface energy at room temperature of 30 mN / m or less. Manufacturing method.   The method for manufacturing a radiation detector according to claim 1, wherein the bonding step is performed in a reduced-pressure atmosphere lower than atmospheric pressure. Wherein the adhesive is a UV-curable adhesive which proceeds the curing reaction by cationic polymerization, wherein arranged in the region having a circuit wiring of the array substrate is irradiated from the opposite side of the moistureproof body of the array substrate, the array The method of manufacturing a radiation detector according to any one of claims 1 to 6, wherein the substrate is cured by ultraviolet light transmitted through the substrate . An array substrate in which photoelectric conversion elements are two-dimensionally arranged on the substrate;
A scintillator layer for covering the region where the photoelectric conversion elements of the array substrate are arranged and converting radiation into fluorescence;
A moisture-proof body provided with a flange facing the portion surrounding the scintillator layer of the array substrate, the molded body covering the scintillator layer;
Protruding protrudes higher than the counter adhesion portion and the outer edge of the flange portion of the opposing adhesive portions bottom in the area protruding outwardly in close contact with the array substrate the collar portion between the array substrate and the flange portion An adhesive layer for adhering the moistureproof body and the array substrate having a portion;
A radiation detector comprising:

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