JP6060752B2 - Flat panel radiation detector and manufacturing method thereof - Google Patents

Description

  The present invention relates to a flat panel radiation detector that measures the spatial distribution of radiation (for example, X-rays, γ rays, etc.) in the medical field, industrial field, and the like, and a method for manufacturing the same.

  Conventionally, as this type of apparatus, there is a direct conversion type flat panel radiation detector (hereinafter referred to as “FPD” as appropriate) (see Patent Documents 1 to 3). This direct conversion type FPD collects charges (carriers) formed on a radiation-sensitive semiconductor layer, a common electrode formed on the surface of the semiconductor layer, to which a predetermined bias voltage is applied, and a back surface of the semiconductor layer. A pixel electrode, an active matrix substrate, and a carrier-selective high-resistance film are provided. When radiation enters the semiconductor layer, a charge is generated, and the generated charge is collected by the pixel electrode and extracted as a radiation detection signal, thereby detecting the radiation.

  In particular, when an amorphous semiconductor thick film such as a-Se (amorphous selenium) is used as the semiconductor layer, the amorphous semiconductor thick film can be easily formed into a thick and wide film by a method such as vacuum deposition. Therefore, it is suitable for constructing a two-dimensional array type FPD that requires a large-area thick film.

  Since the direct conversion type FPD uses a high bias voltage, a problem of creeping discharge occurs. Creeping discharge is a discharge phenomenon that occurs when dielectric breakdown occurs from the outer edge of the common electrode to the active matrix substrate along the outer edge of the amorphous semiconductor thick film. Therefore, Patent Document 1 proposes a configuration in which the surfaces of the semiconductor layer and the common electrode are entirely covered with a discharge preventing film made of a high-voltage insulating material such as silicone resin. Thereby, creeping discharge can be suppressed.

  However, in this structure, the FPD warps due to temperature change, and at least one of the silicone resin film, the amorphous semiconductor thick film, the common electrode, and the carrier-selective high-resistance film cracks, and the breakdown voltage of creeping discharge is reduced. It becomes insufficient. Therefore, in Patent Document 2, an insulating plate material (auxiliary plate) having a thermal expansion coefficient comparable to that of the active matrix substrate is placed on the opposite side of the active matrix substrate with a high-voltage curable synthetic resin (discharge prevention film) interposed therebetween. The structure provided in is proposed. Thereby, the curvature of FPD by a temperature change can be suppressed.

  Furthermore, Patent Document 3 proposes a configuration in which a portion of the curable synthetic resin covering the effective pixel region is made thinner (depressed) than a portion covering the connection region of the lead wire for supplying the bias voltage. Thereby, the stress to a semiconductor layer by the thermal expansion coefficient difference of a semiconductor layer and curable synthetic resin, and the residual stress of curable synthetic resin, and attenuation | damping of a radiation can be suppressed.

JP 2002-009268 A JP 2002-31144 A JP 2005-286183 A

  However, in the configuration of Patent Document 3, it has been found that stress concentrates on the boundary portion where the thickness of the curable synthetic resin changes, causing discharge breakdown. FIG. 11A shows a common electrode at a boundary A where the thickness of the curable synthetic resin layer 123 varies between the portion covering the connection region of the lead wire 121 and the effective pixel region SA, as in the configuration of Patent Document 3. 1 is a plan view showing a conventional flat panel radiation detector (FPD) 101 on 103. FIG. 11B is a BB longitudinal sectional view of FIG. 11A, and FIG. 11C is a longitudinal sectional view of CC of FIG. 11A. In FIG. 11A, the lead wire 121 and the like are shown as a solid line with a solid line. Moreover, illustration of the curable synthetic resin layer 123 is omitted.

  In FIG. 11A, the auxiliary plate 125 of the FPD 101 is notched in the connection region of the lead wire 121, and the boundary portion A passes over the common electrode 103. In the boundary portion A, stress is concentrated due to the difference in thermal expansion coefficient between the semiconductor layer 102 and the curable synthetic resin layer 123 and the residual stress of the curable synthetic resin 123. As a result, a crack or the like occurs in the carrier-selective upper high-resistance film 105 provided between the common electrode 103 and the semiconductor layer 102, and the upper high-resistance film 105 does not function in that portion, and a current path is generated. Creeping discharge occurs through this current path.

  Therefore, in order to suppress the boundary portion A where stress is concentrated, it is necessary to make the thickness of the curable synthetic resin layer 123 uniform, but the thickness of the curable synthetic resin layer 123 may be made thinner than the lead wire 121. The problem that it is not possible arises. In addition, if the thickness of the curable synthetic resin layer 123 is large, even if the auxiliary plate 125 is provided, warpage occurs due to a difference in thermal expansion coefficient, and it can be used for a long time in a place where the temperature environment is severe and there is a temperature difference. The durability against this will be insufficient.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a flat panel type radiation detector that suppresses discharge breakdown and has a long lifetime.

In order to achieve such an object, the present invention has the following configuration.
That is, the flat panel radiation detector according to the present invention includes: (a) a radiation-sensitive semiconductor layer that generates a charge upon incidence of radiation; and (b) formed on the surface of the semiconductor layer and biasing the semiconductor layer. A common electrode for applying a voltage; (c) a carrier-selective high-resistance film provided between the semiconductor layer and the common electrode; and (d) provided on the back surface of the semiconductor layer and formed in the semiconductor layer. An active matrix substrate for reading the generated charge; (e) a bias voltage supply lead connected to the common electrode at a position outside the effective pixel region; (f) the semiconductor layer and the high resistance film; An insulating curable synthetic resin layer covering the common electrode; and (g) an insulating auxiliary fixed to the front side of the curable synthetic resin layer and having a thermal expansion coefficient comparable to that of the active matrix substrate. (H1) The auxiliary plate includes an opening at a position facing the lead wire connecting portion where the lead wire connects to the common electrode, and (h2) the lead wire. Is arranged so as to be pulled out from the opening.

  According to the flat panel radiation detector of the present invention, the lead wire for supplying the bias voltage is drawn out from the opening provided at the position of the auxiliary plate facing the lead wire connecting portion where the lead wire is connected to the common electrode. Are arranged as follows. Thereby, the thickness of a curable synthetic resin layer can be made thinner than a lead wire. In addition, it is possible to suppress the boundary portion where the thickness of the curable synthetic resin layer that has occurred in the portion covering the lead wire connecting portion and the portion covering the effective pixel region changes. That is, the thickness of the curable synthetic resin layer can be reduced and the boundary where the thickness of the curable synthetic resin layer changes can be suppressed. Therefore, it is possible to suppress warping due to a difference in thermal expansion coefficient between the curable synthetic resin layer and the semiconductor layer, stress due to residual stress of the curable synthetic resin layer, and concentration of the stress. Therefore, stress can be reduced and creeping discharge (discharge breakdown) caused by damage due to the stress concentration can be suppressed. In addition, it can have a long life with respect to long-time use in a place where the temperature environment is severe. Moreover, since the thickness of the curable synthetic resin layer can be reduced, attenuation of radiation can be suppressed.

  Further, in the flat panel radiation detector according to the present invention, (i) an insulating blocking portion that blocks the opening in a state where the lead wire is drawn out so as not to leak when the curable synthetic resin is injected. Furthermore, it is preferable to provide. Thereby, it can suppress that it discharges toward the outer housing | casing part from the opening part of an auxiliary | assistant board (discharge destruction). That is, in the method of injecting the curable synthetic resin from the opening of the auxiliary plate, bubbles are likely to adhere to the lead wire, and the problem of discharging from the opening of the auxiliary plate toward the outer casing through the bubbles. There is. Without using this method, the opening with the lead wire pulled out is closed with a blocking portion so that liquid leakage does not occur when the curable synthetic resin is injected, and the curable synthetic resin is injected from a hole other than the opening of the auxiliary plate. Use the method to Thereby, bubbles adhering to the lead wire are suppressed, and discharge from the opening portion of the auxiliary plate toward the outer casing portion can be suppressed.

  Further, in the flat panel radiation detector according to the present invention, the closing portion includes an insulating lid that covers the opening from the opposite side of the common electrode across the auxiliary plate, the opening, and the lead It is preferable to include a filling portion in which a gap between the wire and the lid portion is filled with an insulating synthetic resin. As a result, it is possible to suppress discharge from the opening of the auxiliary plate toward the outer casing more firmly than the configuration in which the opening in the state where the lead wire is drawn out is closed only with the insulating synthetic resin. it can. That is, since it is already covered with a solid material, it is easy to obtain a predetermined shape and air bubbles are difficult to enter. In addition, the amount of synthetic resin to be filled is small, and the curing time can be shortened.

  In the flat panel radiation detector according to the present invention, it is preferable that a bias voltage of 2 kV or more is applied to the common electrode. Even when a high voltage of 2 kV or higher is applied, it is possible to suppress discharge from the opening of the auxiliary plate toward the outer casing.

  The flat panel radiation detector according to the present invention preferably further includes an insulating sheet that covers the blocking portion. Thereby, it is possible to suppress the discharge from the opening portion of the auxiliary plate to the outer casing portion more firmly.

  In the flat panel radiation detector according to the present invention, it is preferable that the insulating sheet is one of Teflon (registered trademark) and polyimide. These can be easily obtained by a commercial route, and can easily form a discharge prevention structure having a very high withstand voltage.

  In the flat panel radiation detector according to the present invention, it is preferable that the thickness of the curable synthetic resin layer is constant over the common electrode except for the lead wire connecting portion and the opening. . Thereby, the concentration of stress can be suppressed, and creeping discharge due to the stress concentration can be suppressed. The lead wire connecting portion and the opening have different thicknesses, but the stress concentration is not so great as to cause creeping discharge. In addition, stress concentration occurs in a portion other than the common electrode where the thickness of the curable synthetic resin layer is different, but since no electric field is applied, creeping discharge does not occur.

  In the flat panel radiation detector according to the present invention, it is preferable that the thickness of the curable synthetic resin layer is thinner than the diameter of the lead wire in the entire area on the common electrode. Thereby, the warp due to the difference in thermal expansion coefficient between the curable synthetic resin layer and the semiconductor layer and the stress due to the residual stress of the curable synthetic resin layer can be suppressed, and creeping discharge can be suppressed. Moreover, attenuation of radiation can be suppressed.

The flat panel radiation detector manufacturing method according to the present invention includes: (A) a radiation-sensitive semiconductor layer that generates a charge upon incidence of radiation; and (B) a semiconductor layer formed on a surface of the semiconductor layer. A common electrode for applying a bias voltage to the layer; (C) a carrier-selective high-resistance film provided between the semiconductor layer and the common electrode; and (D) a semiconductor electrode provided on the back surface of the semiconductor layer. An active matrix substrate for reading out the charges generated in the layer; (E) a bias voltage supply lead connected to the common electrode at a position outside the effective pixel region; and (F) the semiconductor layer and the high layer An insulating curable synthetic resin layer covering the resistance film and the common electrode; and (G) an insulating property fixed on the front side of the curable synthetic resin layer and having a thermal expansion coefficient comparable to that of the active matrix substrate. In a manufacturing method of a flat panel radiation detector provided with an auxiliary plate, (H) the lead wire from the opening provided at the position of the auxiliary plate facing the lead wire connecting portion connected to the common electrode (I) a step of closing the opening in a state where the lead wire is drawn out with a closing portion so as not to leak liquid when the curable synthetic resin is injected, and (J) And a step of injecting and curing a curable synthetic resin into a space surrounded by the semiconductor layer, the common electrode, the active matrix substrate, and the auxiliary plate after the opening is closed by the closing portion. It is characterized by this.

  According to the flat panel radiation detector manufacturing method of the present invention, the bias voltage supply lead wire has an opening provided at the position of the auxiliary plate facing the lead wire connecting portion where the lead wire connects to the common electrode. It is arranged to pull out from the part. Thereby, the thickness of a curable synthetic resin layer can be made thinner than a lead wire. In addition, it is possible to suppress the boundary portion where the thickness of the curable synthetic resin layer that has occurred in the portion covering the lead wire connecting portion and the portion covering the effective pixel region changes. That is, the thickness of the curable synthetic resin layer can be reduced and the boundary where the thickness of the curable synthetic resin layer changes can be suppressed. Therefore, it is possible to suppress warping due to a difference in thermal expansion coefficient between the curable synthetic resin layer and the semiconductor layer, stress due to residual stress of the curable synthetic resin layer, and concentration of the stress. Therefore, stress can be reduced and creeping discharge (discharge breakdown) caused by damage due to the stress concentration can be suppressed. In addition, it can have a long life with respect to long-time use in a place where the temperature environment is severe. Moreover, since the thickness of the curable synthetic resin layer can be reduced, attenuation of radiation can be suppressed.

  In addition, the opening with the lead wire drawn out is closed with a closing portion so that liquid does not leak when the curable synthetic resin is injected, and then cured into a space surrounded by the semiconductor layer, the common electrode, the active matrix substrate, and the auxiliary plate. A synthetic resin is injected and cured. In the method of injecting the curable synthetic resin from the opening of the auxiliary plate, bubbles easily adhere to the lead wire, and there is a problem of discharging from the opening of the auxiliary plate toward the outer casing through the bubbles. . Without using this method, the opening with the lead wire pulled out is closed with a blocking portion so that liquid leakage does not occur when the curable synthetic resin is injected, and the curable synthetic resin is injected from a hole other than the opening of the auxiliary plate. Use the method to Thereby, bubbles adhering to the lead wire are suppressed, and discharge (discharge breakdown) from the opening of the auxiliary plate toward the outer casing can be suppressed.

  According to the flat panel radiation detector of the present invention, the lead wire for supplying the bias voltage is drawn out from the opening provided at the position of the auxiliary plate facing the lead wire connecting portion where the lead wire is connected to the common electrode. Are arranged as follows. Thereby, the thickness of a curable synthetic resin layer can be made thinner than a lead wire. In addition, it is possible to suppress the boundary portion where the thickness of the curable synthetic resin layer that has occurred in the portion covering the lead wire connecting portion and the portion covering the effective pixel region changes. That is, the thickness of the curable synthetic resin layer can be reduced and the boundary where the thickness of the curable synthetic resin layer changes can be suppressed. Therefore, it is possible to suppress warping due to a difference in thermal expansion coefficient between the curable synthetic resin layer and the semiconductor layer, stress due to residual stress of the curable synthetic resin layer, and concentration of the stress. Therefore, stress can be reduced and creeping discharge (discharge breakdown) caused by damage due to the stress concentration can be suppressed. In addition, it can have a long life with respect to long-time use in a place where the temperature environment is severe. Moreover, since the thickness of the curable synthetic resin layer can be reduced, attenuation of radiation can be suppressed.

  Further, according to the method for manufacturing a flat panel radiation detector according to the present invention, after the opening in the state where the lead wire is drawn out is blocked by the closing portion so as not to leak when the curable synthetic resin is injected. A curable synthetic resin is injected into a space surrounded by the semiconductor layer, the common electrode, the active matrix substrate, and the auxiliary plate and cured. In the method of injecting the curable synthetic resin from the opening of the auxiliary plate, bubbles easily adhere to the lead wire, and there is a problem of discharging from the opening of the auxiliary plate toward the outer casing through the bubbles. . Without using this method, the opening with the lead wire pulled out is closed with a blocking portion so that liquid leakage does not occur when the curable synthetic resin is injected, and the curable synthetic resin is injected from a hole other than the opening of the auxiliary plate. Use the method to Thereby, bubbles adhering to the lead wire are suppressed, and discharge (discharge breakdown) from the opening of the auxiliary plate toward the outer casing can be suppressed.

(A) is a top view of the flat panel type radiation detector (FPD) which concerns on an Example, (b) is a longitudinal cross-sectional view of (a). It is a block diagram which shows the structure of an active matrix substrate and its periphery. It is a longitudinal cross-sectional view which expands and shows the lead wire connection part of FIG.1 (b). It is a flowchart which shows the manufacturing method of the flat panel type radiation detector (FPD) which concerns on an Example. (A) is a top view which expands and shows the state which pulled out the lead wire from the opening part of the auxiliary | assistant board, (b) is the longitudinal cross-sectional view. (A) is a top view which expands and shows the state which has arrange | positioned the cover part, (b) is the longitudinal cross-sectional view. (A) is a top view which expands and shows the state which filled the clearance gap with the insulating synthetic resin, (b) is the longitudinal cross-sectional view. It is a longitudinal cross-sectional view with which it uses for description of an effect. It is a longitudinal cross-sectional view of the flat panel type radiation detector (FPD) which concerns on a modification. It is a longitudinal cross-sectional view of the flat panel type radiation detector (FPD) which concerns on a modification. (A) is a top view of the conventional flat panel type radiation detector (FPD), (b) is a BB longitudinal cross-sectional view of (a), (c) is C of (a). It is -C sectional drawing.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a plan view of a flat panel radiation detector (FPD) according to the embodiment, and FIG. 1B is a longitudinal sectional view of FIG. In FIG. 1A, the illustration of the curable synthetic resin layer 23 is omitted.

  Please refer to FIG. 1 (a) and FIG. 1 (b). The FPD 1 includes a radiation-sensitive semiconductor film 2 that generates a charge upon incidence of radiation (for example, X-rays), and a common electrode 3 made of a metal thin film that applies a bias voltage to the semiconductor film 2, and an active matrix substrate 4 in that order. Are laminated.

  The semiconductor layer 2 is composed of an amorphous semiconductor film such as a-Se (amorphous selenium) or a compound semiconductor film such as CdTe (cadmium telluride) or CdZnTe (zinc cadmium telluride). The thickness of the semiconductor layer 2 is usually configured to be about 0.5 mm to 1.5 mm.

A carrier-selective upper high-resistance film 5 is provided between the semiconductor layer 2 and the common electrode 3, and carrier selectivity is provided between the semiconductor layer 2 and a pixel electrode 7 (active matrix substrate 4) to be described later. The lower high resistance film 6 is provided. The upper high resistance film 5 is made of Sb ₂ S ₃ (antimony trisulfide), and the lower high resistance film 6 is made of Sb ₂ S ₃ . An organic film layer (not shown) such as polycarbonate mixed with a hole (or electron) transfer agent may be further formed between the semiconductor layer 2 and the high resistance film 5. The upper high resistance film 5 corresponds to the high resistance film in the present invention.

  The upper high resistance film 5 is an N type (hole injection blocking type) selection film when a positive bias is applied to the common electrode 3, and a P type (when a negative bias is applied to the common electrode 3. An electron injection blocking type selective membrane is used. On the other hand, the lower high-resistance film 6 is a P-type (electron injection blocking) selection film when a positive bias is applied to the common electrode 3, and an N-type (positive) when a negative bias is applied to the common electrode 3. A hole injection blocking type) selective membrane is used. However, the multilayer structure is not limited to this.

In addition to Sb ₂ S ₃ , semiconductors used for the upper and lower high resistance films 5 and 6 include ZnTe (zinc telluride), CeO ₂ (cerium oxide), CdS (cadmium sulfide), and ZnSe (selenide). Zinc), polycrystalline semiconductors such as ZnS (zinc sulfide), Se (selenium) and Se compounds doped with alkali metals such as Na (sodium), halogens such as Cl (chlorine), As (arsenic), and Te (tellurium) The amorphous semiconductor is excellent in suitability for large area.

  The active matrix substrate 4 includes a pixel electrode 7 that collects charges generated in the semiconductor film 2, a charge readout circuit 8 that reads the charges generated in the semiconductor layer 2 and collected in the pixel electrode 7, and the pixel electrodes 7 and charges. And an insulating substrate 9 on which a readout circuit 8 is formed. The pixel electrode 7 is composed of a plurality, and is arranged in a two-dimensional matrix within the effective pixel region SA as shown in FIG. The common electrode 3 and the pixel electrode 7 are made of a suitable metal such as Au (gold), Pt (platinum), Ni (nickel), In (indium), ITO (indium tin oxide), or the like. The insulating substrate 9 is made of glass or the like.

  As shown in FIG. 2, the charge readout circuit 8 includes a capacitor 8a for accumulating charges collected by the pixel electrode 7, and a TFT (thin film field effect transistor) 8b which is a switching element for reading out the charges accumulated in the capacitor 8a. A gate line 8c and a data line 8d.

  One capacitor 8 a and one TFT 8 b are provided for each pixel electrode 7. The capacitor 8a is connected to the drain of the TFT 8b. The gate line 8c is connected to the gate of each TFT 8b arranged in one column in the row direction (X direction) in FIG. The gate line 8c is connected to the gate driver 11 in order to send a read signal to the TFT 8b.

  The data line 8d is connected to the source of each TFT 8b arranged in one column in the column direction (Y direction) in FIG. The data line 8d is connected to the charge voltage type amplifier 13, and the detection signals read out by the data line 8d are sequentially sent to the charge voltage type amplifier 13, the multiplexer 15 and the A / D converter 17. , And output to the outside of the FPD 1. Further, the gate driver 11, the charge voltage type amplifier 13, the multiplexer 15, the A / D converter 17, the bias voltage supply source (not shown) and the like are controlled by a controller 19 including a CPU.

  Returning to FIG. 1 (a) and FIG. 1 (b). A lead wire 21 for supplying a bias voltage is connected to the common electrode 3. The lead wire 21 is connected to the common electrode 3 at a position outside the effective pixel area SA. Details of the connecting portion of the lead wire 21 will be described later.

  The semiconductor film 2 and the common electrode 3 are covered with a curable synthetic resin layer 23 as a protective mold. The curable synthetic resin layer 23 is made of an epoxy resin or the like. An insulating auxiliary plate 25 having a thermal expansion coefficient similar to that of the active matrix substrate 4 is fixed to the front side of the curable synthetic resin layer 23. The auxiliary plate 25 is made of quartz glass or the like. The auxiliary plate 25 is fixed to the active matrix substrate 4 via a spacer 27. The spacer 27 is made of polycarbonate resin, ABS resin, or the like.

  The spacer 27 includes a spacer frame portion 27a that encloses the side of the semiconductor layer 2 and the like, and a window frame portion 27b that covers the upper side of the semiconductor layer 2 and the like and that is opened with an area smaller than the inner wall of the spacer frame portion 27a. Yes. The spacer 27 fixes the auxiliary plate 25 at the opening outer peripheral portion of the window frame portion 27 b of the spacer 27 from the opposite side of the common electrode 3 across the auxiliary plate 25.

  The FPD body in which the semiconductor layer 2, the common electrode 3, the active matrix substrate 4, the upper and lower high resistance films 5 and 6, the lead wire 21, the curable synthetic resin layer 23, the auxiliary plate 25, the spacer 27, etc. are integrated. Is supported by the housing 29 and housed therein.

  Next, the configuration of the lead wire connecting portion 30 will be described. FIG. 3 is an enlarged longitudinal sectional view showing the lead wire connecting portion 30 of FIG. The lead wire connecting portion 30 includes a metal plate 31 and a conductive adhesive 33 that fixes the metal plate 31 and the common electrode 3. The lead wire 21 is connected to the common electrode 3 as described above. Specifically, the lead wire 21 is connected to the common electrode 3 with a metal plate 31 and a conductive adhesive 33 interposed therebetween. The lead wire 21 includes a conductive wire portion 21 a and an insulating coating portion 21 b that covers the conductive portion 21 a, and the conductive wire portion 21 a is soldered to the metal plate 31.

  The metal plate 31 is made of Cu (copper) or the like. However, the metal plate 31 may be formed by applying Au plating on the surface of the Cu plate to lower the resistance value and prevent corrosion. The conductive adhesive 33 is made of Ni containing nickel, such as Ni (nickel) acrylic paste, or carbon paste containing carbon. The lead wire portion 21a of the lead wire 21 is made of Cu or the like. The diameter E of the lead wire 21 is about 2 mm. In the present specification, the region LC of the lead wire connecting portion 30 indicates a region where the conductive adhesive 33 is formed.

  Next, features of the present invention will be described. In the conventional apparatus shown in FIGS. 11A to 11C, the lead wires 121 are connected to the active matrix substrate 104, the auxiliary plate 123, and the spacer 127 from the spacer frame portion 127a of the spacer 127 that surrounds the side of the semiconductor layer 102 and the like. It is drawn outside the space surrounded by etc. In this regard, in the present invention, the lead wire 21 is drawn from the auxiliary plate 25.

  That is, as shown in FIG. 3, the auxiliary plate 25 includes an opening 25 a at a position facing the lead wire connecting portion 30 where the lead wire 21 is connected to the common electrode 3. The lead wire 21 is disposed so as to be drawn out from the opening 25a. Further, the opening 25 a in a state where the lead wire 21 is drawn out is closed by a closing portion 35. The closing portion 35 prevents the bias voltage of the lead wire connecting portion 30 from discharging from the opening portion 25a toward the outer casing portion 29, and also prevents liquid leakage when injecting the curable synthetic resin. It is. In addition, the auxiliary | assistant board 25 is provided so that the semiconductor layer 2 containing the common electrode 3 may be covered other than the opening part 25a in Fig.1 (a) and FIG.1 (b).

  As shown in FIG. 3, the blocking portion 35 includes a lid portion 37 that covers the opening portion 25 a from the opposite side of the common electrode 3 across the auxiliary plate 25, and a gap between the opening portion 25 a, the lead wire 21, and the lid portion 37. A filling portion 39 filled with an insulating synthetic resin (synthetic resin adhesive) is provided. The lid portion 37 is made of polycarbonate resin, ABS resin, acrylic resin, or the like. The thickness of the lid portion 37 is preferably about 1 mm, and may be about 0.5 to 3.0 mm.

  The lid portion 37 does not prevent the lead wire 21 from passing through the opening portion 25a and closes a part of the opening portion 25a. The lid portion 37 has, for example, a cutout portion 37a (see FIG. 6A) for receiving the lead wire 21, and is formed in a U shape. The lead wire 21 in the drawn-out state is arranged along the notch 37a to suppress the lead wire 21 from protruding. An epoxy resin or the like is used as the synthetic resin constituting the filling portion 39. The filling portion 39 adheres the lid portion 37 to the auxiliary plate 25 and fills the gap so as to fill the opening portion 25 a and the notch portion 37 a of the lid portion 37.

  The filling unit 39 may protrude and cover the gap while filling the gap. Further, if the filling portion 39 is sufficiently filled, it is not necessary to fill all of the notch portion 37a up to the inlet side.

  Further, the closing portion 35 is covered with an insulating sheet 41. That is, the insulating sheet 41 is provided so as to cover the closing portion 35, the opening 25a, and a part of the lead wire 21 drawn from the opening 25a. The insulating sheet 41 is made of either Teflon (registered trademark) or polyimide. These can be easily obtained by a commercial route, and can easily form a discharge prevention structure having a very high withstand voltage.

  The thickness of the curable synthetic resin layer 23 is constant over the common electrode 3 except for the region LC of the lead wire connecting portion 30 and the opening 25a. Thereby, the concentration of stress can be suppressed, and creeping discharge due to the stress concentration can be suppressed. In addition, although area | region LC and the opening part 25a of the lead wire connection part 30 differ in thickness, stress concentration is not so large that it leads to creeping discharge. Further, stress concentration occurs in a portion where the thickness of the curable synthetic resin layer 23 is different in a portion other than on the common electrode 3, but a creeping discharge does not occur because no electric field is applied.

  Specifically, the region LC and the opening 25a of the lead wire connecting portion 30 are regions indicated by a symbol F in FIGS. 5 (a) and 5 (b). In FIG. 5A, the symbol F is shown larger for convenience of illustration.

  Further, the thickness of the curable synthetic resin layer 23 is thinner than the diameter E (see FIG. 3) of the lead wire 21 in the entire region on the common electrode 3. Thereby, the warpage due to the difference in thermal expansion coefficient between the curable synthetic resin layer 23 and the semiconductor layer 2 and the stress due to the residual stress of the curable synthetic resin layer 23 can be suppressed, and creeping discharge can be suppressed. Moreover, attenuation of radiation can be suppressed.

<Operation of FPD1>
Next, the operation of the FPD 1 will be described. When the radiation is detected by the FPD 1, a bias voltage is applied to the common electrode 3 from a bias voltage supply source (not shown) at 2 kV to 25 kV. The bias voltage is applied to the common electrode 3 through the lead wire 21 and the metal plate 31. In a state where a bias voltage is applied, charges are generated by the semiconductor layer 2 as radiation is incident. The generated charges are collected by the pixel electrodes 7 arranged in a two-dimensional matrix. The collected charge is taken out as a radiation detection signal for each pixel electrode 7 by the charge readout circuit 8.

  Specifically, the charges collected by the pixel electrode 7 are temporarily stored in the capacitor 8a. Then, the gate driver 11 gives a read signal to the gate line 8c in order, for example, from the upper side of the drawing in FIG. When the read signal is supplied to the gate line 8c, the gate of the TFT 8b connected to the gate line 8c is changed from the OFF state to the ON state, and the charge accumulated in the capacitor 8a is read through the data line 8d. The read charge is amplified by the charge-voltage conversion type 13 and output as a voltage signal. The multiplexer 15 selects and outputs one voltage signal from the plurality of voltage signals. The output voltage signal is converted from an analog signal to a digital signal by the A / D converter 17. A two-dimensional radiation image is obtained based on the converted digital signal.

<Method for manufacturing FPD1>
Next, a method for manufacturing the FPD 1 will be described with reference to FIG. An active matrix substrate 4 is prepared (step S01). On the active matrix substrate 4, the lower high resistance film 6, the semiconductor layer 2, the upper high resistance film 5, and the common electrode 3 are formed in order using a vacuum evaporation apparatus or the like (step S02). Thereafter, as shown in FIGS. 1A and 3, a metal plate 31, a conductive adhesive 33, a lead wire 21 and the like are provided on the common electrode 3 outside the effective pixel area SA (step S03).

  The auxiliary plate 25 is provided with an opening 25a facing the lead wire connecting portion 30 where the lead wire 21 is connected to the common electrode 3. The auxiliary plate 25 having the opening 25 a is fixed to the spacer 27. The semiconductor layer 2 and the like are covered with the auxiliary plate 25 and the spacer 27 so as to maintain a predetermined distance between the common electrode 3 and the auxiliary plate 25 (step S04). At this time, as shown in FIGS. 5A and 5B, the lead wire 21 is pulled out from the opening 25a. That is, the lead wire 21 is arranged so as to be drawn out from the opening 25 a provided in the auxiliary plate 25 facing the lead wire connecting portion 30 that connects to the common electrode 3.

  Thereafter, the opening 25a in a state where the lead wire 21 is drawn out is closed by the closing portion 35 so as not to leak when the curable synthetic resin is injected (step S05). As shown in FIGS. 6A and 6B, a lid 37 is installed on the opening 25a in a state where the lead wire 21 is pulled out. At this time, the opening 25 a is closed while receiving the lead wire 21 from the notch 37 a of the lid 37. Then, the auxiliary plate 25 is fixed using an insulating synthetic resin, and the gap between the lead wire 21 drawn from the opening 25a and the opening 25a is filled and sealed. Since the insulating synthetic resin is filled with a high viscosity, it can be closed without dripping. The insulating synthetic resin fills the gaps by a method such as putty coating. Moreover, when filling with a nozzle, since a viscosity is high, a high pressure is required. Thereby, the filling part 39 is formed (refer Fig.7 (a) and FIG.7 (b)).

  After the opening 25a is closed by the closing portion 35, a liquid curable synthetic resin is injected into a space surrounded by the semiconductor layer 2, the common electrode 3, the active matrix substrate 4, the auxiliary plate 25, the spacer 27, and the like, and cured. (Step S06). At this time, for example, liquid curable synthetic resin is injected from an injection port 43 (see FIG. 1B) provided in the spacer 27 and cured. As the curable synthetic resin, for example, a low-temperature room temperature curable epoxy resin agent is used. Thereby, the curable synthetic resin layer 23 is formed.

  FPD1 is obtained by the above manufacturing method. The insulating sheet 41 covering the blocking portion 35 may be provided after the closing portion 35 is formed, or may be provided after the curable synthetic resin layer 23 is formed. In steps S03 and S04, the lead wire 21 is passed through the opening 25a of the auxiliary plate 25 after being soldered to the metal plate 31. In this regard, the lead wire 21 may be soldered to the metal plate 31 after passing through the opening 25 a of the auxiliary plate 25.

  The effect of this manufacturing method will be described. After the opening 25a with the lead wire 21 drawn out is closed with a closing portion 35 so as not to leak when the curable synthetic resin is injected, the semiconductor layer 2, the common electrode 3, the active matrix substrate 4, the auxiliary plate 25, etc. A curable synthetic resin is injected into the space surrounded by, and cured. In the method of injecting the curable synthetic resin from the opening 25a of the auxiliary plate 25, as shown in FIG. 8, bubbles G are likely to adhere to the lead wire 21, and an amorphous semiconductor thick film such as a-Se is used as a radiation sensitive type. When used as a semiconductor layer, since it is necessary to apply a high voltage of 2 kV or more, there is a problem of discharging from the opening 25a of the auxiliary plate 25 toward the outer casing 29 through the bubbles G. Without using this method, the opening 25a in a state where the lead wire 21 is drawn out is closed with a closing portion 35 so as not to leak when the curable synthetic resin is injected, and the inlet 43 other than the opening 25a of the auxiliary plate 25 is closed. A method of injecting a curable synthetic resin is used. Thereby, the bubble G adhering to the lead wire 21 is suppressed, and discharge from the opening 25a of the auxiliary plate 25 toward the outer casing 29 can be suppressed.

<Experimental result>
In order to confirm the effect of this example, the following experiment was performed. First, ten experimental detectors (FPD1) having the structure of the present embodiment (see FIGS. 1A and 1B) are manufactured, and as conventional devices, FIGS. Seven comparative detectors (FPD101) having the structure of (c) were manufactured. Then, a bias voltage of 30 kV was applied to the common electrodes 3 and 103 for 10 minutes to compare the resistance to creeping discharge. The results are shown in Table 1. Note that the bias voltage of 30 kV is a value 20% higher than 25 kV set as the upper limit.

  As shown in the results of Table 1, creeping discharge was not confirmed in the experimental detector (FPD1). On the other hand, in the comparative detector (FPD101), creeping discharge was confirmed in 5 out of 7 units, and the discharge site was a boundary portion. As is apparent from this result, the experimental detector (FPD1) of the present embodiment in which the boundary portion is suppressed can improve the resistance to creeping discharge. Therefore, even if the thickness of the curable synthetic resin layer 23 is reduced, the discharge resistance can be improved more than that of the conventional detector for comparison (FPD 101). A long-life and high-performance FPD can be obtained for use.

  According to the present embodiment, the lead wire 21 for supplying the bias voltage is drawn out from the opening 25 a provided at the position of the auxiliary plate 25 facing the lead wire connecting portion 30 where the lead wire 21 is connected to the common electrode 3. Is arranged. Thereby, the thickness of the curable synthetic resin layer 23 can be made thinner than the lead wire 21. Further, it is possible to suppress the boundary portion A where the thickness of the curable synthetic resin layer 23 generated in the portion covering the lead wire connecting portion 30 and the portion covering the effective pixel region SA changes. That is, the thickness of the curable synthetic resin layer 23 can be reduced, and the boundary portion A where the thickness of the curable synthetic resin layer 23 changes can be suppressed. Therefore, it is possible to suppress warping due to a difference in thermal expansion coefficient between the curable synthetic resin layer 23 and the semiconductor layer 2, stress due to residual stress of the curable synthetic resin layer 23, and concentration of the stress. Therefore, stress can be reduced and creeping discharge caused by damage due to the stress concentration can be suppressed. In addition, it can have a long life with respect to long-time use in a place where the temperature environment is severe. Moreover, since the thickness of the curable synthetic resin layer 23 can be reduced, attenuation of radiation can be suppressed.

  The FPD 1 further includes an insulating closing portion 35 that closes the opening 25a in a state where the lead wire 21 is drawn out so as not to leak when the curable synthetic resin is injected. Thereby, it can suppress that it discharges toward the outer housing | casing part 29 from the opening part 25a of the auxiliary | assistant board 25. FIG.

  The closing portion 35 includes an insulating lid portion 37 that covers the opening portion 25a from the opposite side of the common electrode 3 with the auxiliary plate 25 interposed therebetween, and a gap between the opening portion 25a, the lead wire 21, and the lid portion 37 that is an insulating synthetic resin. And a filling part 39 filled with As a result, the discharge from the opening 25a of the auxiliary plate 25 toward the outer casing 29 is performed more firmly than the configuration in which the opening 25a in the state where the lead wire 21 is drawn out is closed only by the insulating synthetic resin. That can be suppressed. That is, since it is already covered with a solid material, it is easy to obtain a predetermined shape, and bubbles G (see FIG. 8) are difficult to enter. In addition, the amount of synthetic resin to be filled is small, and the curing time can be shortened.

  The FPD 1 further includes an insulating sheet 41 that covers the blocking portion 35. Thereby, it is possible to suppress the discharge from the opening 25a of the auxiliary plate 25 toward the outer casing 29 more firmly.

  The present invention is not limited to the above embodiment, and can be modified as follows.

  (1) In the Example mentioned above, it is anticipated that the effect which suppresses creeping discharge will become weak because the thickness of the curable synthetic resin layer 23 becomes thin. In this regard, as shown in FIGS. 9A and 9B, the FPD 51 may be configured such that the barrier layer 53 is provided on the outer edge of the common electrode 3 (see International Publication No. 2010/042930). ). Thereby, it can avoid that the effect which suppresses creeping discharge becomes weak.

  That is, the PFD 51 includes a barrier layer 53 that covers the common electrode 3 and the upper high resistance film 5 along the outer edge of the common electrode 3. The barrier layer 53 prevents the chemical reaction that lowers the resistance between the semiconductor layer 2 and the curable synthetic resin layer 23 and has adhesiveness with the curable synthetic resin layer 23. . The barrier layer 53 is made of an insulating material that does not chemically react with the semiconductor layer 2. The barrier layer 53 may be formed on at least the upper surface of the upper high resistance film 5 so as to be in contact with the side surface of the common electrode 3 without providing a gap with the common electrode 3.

  As the material of the barrier layer 53, for example, a non-amine synthetic resin such as an acrylic resin, a polyurethane resin, a polycarbonate resin, or a synthetic rubber dissolved in a non-amine solvent is used. In addition, as the non-amine solvent, any one or a mixture of toluene, butyl acetate, methyl ethyl ketone, methylcyclohexane, ethylcyclohexane, xylene, dichlorobenzene, or the like is used. The barrier layer 53 is formed at a temperature lower than 40 ° C.

  (2) In the above-described embodiment and modification example (1), the closing portion 35 includes the lid portion 37 and the filling portion 39 that fills the gap, but is not limited thereto. As shown in FIG. 10, the closing portion 35 may be configured by filling only the insulating synthetic resin constituting the filling portion 39 without using the lid portion 37.

  (3) In the above-described embodiments and modifications, the spacer 27 fixes the auxiliary plate 25 from the opposite side of the common electrode 3 with the auxiliary plate 25 interposed therebetween. In this respect, for example, as shown in FIG. 8, the auxiliary plate 25 may be fixed from the common electrode 3 side. That is, the spacer 28 is interposed between the active matrix substrate 4 and the auxiliary plate 25.

1,51 ... Flat panel radiation detector (FPD)
DESCRIPTION OF SYMBOLS 2 ... Semiconductor film 3 ... Common electrode 4 ... Active matrix substrate 21 ... Lead wire 23 ... Curable synthetic resin layer 25 ... Auxiliary plate 25a ... Opening part 30 ... Lead wire connection part 35 ... Closure part 37 ... Cover part 39 ... Filling part 41 ... Insulating sheet A ... Boundary SA ... Effective pixel area

Claims (9)

(A) a radiation-sensitive semiconductor layer that generates electric charge upon incidence of radiation;
(B) a common electrode formed on a surface of the semiconductor layer and applying a bias voltage to the semiconductor layer;
(C) a carrier-selective high-resistance film provided between the semiconductor layer and the common electrode;
(D) an active matrix substrate that is provided on the back surface of the semiconductor layer and reads out the electric charges generated in the semiconductor layer;
(E) a lead wire for supplying a bias voltage connected to the common electrode at a position outside the effective pixel region;
(F) an insulating curable synthetic resin layer covering the semiconductor layer, the high-resistance film, and the common electrode;
(G) In a flat panel radiation detector comprising an insulating auxiliary plate fixed to the front side of the curable synthetic resin layer and having a thermal expansion coefficient comparable to that of the active matrix substrate,
(H1) The auxiliary plate includes an opening at a position facing the lead wire connecting portion where the lead wire connects to the common electrode,
(H2) The flat panel radiation detector, wherein the lead wire is disposed so as to be drawn out from the opening. The flat panel radiation detector according to claim 1,
(I) A flat panel type radiation detection method further comprising an insulating blocking portion that blocks the opening in a state where the lead wire is drawn out so as not to leak when the curable synthetic resin is injected. vessel. The flat panel radiation detector according to claim 2,
The closing portion includes an insulating lid that covers the opening from the opposite side of the common electrode across the auxiliary plate, and a gap between the opening, the lead wire, and the lid with an insulating synthetic resin. A flat panel radiation detector, comprising: a filled portion filled therein. The flat panel radiation detector according to claim 2 or 3,
A flat panel radiation detector, wherein a bias voltage of 2 kV or more is applied to the common electrode. The flat panel radiation detector according to any one of claims 2 to 4,
A flat panel radiation detector, further comprising an insulating sheet covering the closed portion. The flat panel radiation detector according to claim 5,
The flat sheet type radiation detector, wherein the insulating sheet is one of Teflon (registered trademark) and polyimide. The flat panel radiation detector according to any one of claims 1 to 6,
The flat panel radiation detector is characterized in that the thickness of the curable synthetic resin layer is constant throughout the common electrode except for the lead wire connecting portion and the opening. The flat panel radiation detector according to claim 7,
The flat panel radiation detector according to claim 1, wherein a thickness of the curable synthetic resin layer is thinner than a diameter of the lead wire in the entire region on the common electrode. (A) a radiation-sensitive semiconductor layer that generates an electric charge upon incidence of radiation;
(B) a common electrode that is formed on the surface of the semiconductor layer and applies a bias voltage to the semiconductor layer;
(C) a carrier-selective high-resistance film provided between the semiconductor layer and the common electrode;
(D) an active matrix substrate that is provided on the back surface of the semiconductor layer and reads out charges generated in the semiconductor layer;
(E) a bias voltage supply lead connected to the common electrode at a position outside the effective pixel region;
(F) an insulating curable synthetic resin layer covering the semiconductor layer, the high-resistance film, and the common electrode;
(G) In the method of manufacturing a flat panel radiation detector comprising an insulating auxiliary plate fixed to the front side of the curable synthetic resin layer and having a thermal expansion coefficient comparable to that of the active matrix substrate,
(H) a step of arranging the lead wire so as to draw out the lead wire from an opening provided at a position of the auxiliary plate facing a lead wire connecting portion connected to the common electrode;
(I) a step of closing the opening in a state where the lead wire is drawn out with a closing portion so as not to leak when the curable synthetic resin is injected;
(J) After closing the opening with the closing portion, injecting and curing a curable synthetic resin in a space surrounded by the semiconductor layer, the common electrode, the active matrix substrate, and the auxiliary plate;
A method of manufacturing a flat panel radiation detector.

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