JP2005286183A - Flat-panel radiation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently reduce stresses in a semiconductor layer caused by a hardening synthetic resin film, while keeping the creeping discharge preventing function of the curing synthetic resin film of high breakdown voltage which covers a radiation-sensitive semiconductor layer. <P>SOLUTION: In a flat panel radiation detector, a radiation sensitive semiconductor film 1 and a common electrode 2 are covered with a hardening synthetic resin film 8 of a high breakdown voltage as a protective mold coating, so that a thin film 8A covering an effective pixel region SA is made thinner than a thick film 8a, covering a connection region of a lead wire 4 for bias voltage supply. Since the hardening synthetic resin film 8 is made thin throughout its wide range, a stress imposed on the radiation-sensitive semiconductor film 1 caused by the hardening synthetic resin film 8 of the high breakdown voltage can be reduced fully. With regard to the hardening synthetic resin film 8, on the contrary, since the thick film 8a covering the connection region of the lead wire 4 for the bias voltage supply is thicker than the thin film 8A covering the effective pixel region SA, the creeping discharge preventing function of the hardening synthetic resin film can be suppressed from being reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a direct-conversion type radiation detector that includes a radiation-sensitive semiconductor layer that generates an electric charge upon incidence of radiation, and is used in the medical field, industrial field, nuclear power field, and the like. The present invention relates to a technique for reducing stress applied to a sensitive semiconductor layer.

  A direct conversion type flat panel radiation (for example, X-ray) detector having a radiation-sensitive semiconductor layer that generates a charge upon incidence of radiation is obtained after the incident radiation (for example, X-ray) is first converted into light. Unlike the indirect type detector in which the converted light is further converted into an electric signal by photoelectric conversion, incident radiation is immediately converted into electric charge as an electric signal in the radiation-sensitive semiconductor layer.

  In the case of a direct conversion type flat panel radiation detector (hereinafter abbreviated as “FPD” where appropriate), as shown in FIG. 13, a radiation-sensitive semiconductor film 51 that generates electric charges upon incidence of radiation, and the semiconductor film A common electrode 52 for applying a bias voltage to 51 is stacked on the active matrix substrate 53 in that order. The active matrix substrate 53 is formed with a charge readout circuit (not shown) for reading out the charges generated in the semiconductor film 51, and individual electrodes for pixel electrodes (not shown) are two-dimensionally formed in the effective pixel area SA on the surface. It is formed of a matrix array. A lead wire 54 for supplying bias voltage is connected to the common electrode 52 at a position outside the effective pixel area SA. The semiconductor film 51 and the common electrode 52 are covered with a high pressure-resistant curable synthetic resin film 56. An insulating auxiliary plate 55 having a thermal expansion coefficient similar to that of the active matrix substrate 53 is fixed to the front side of the curable synthetic resin film 56.

  When an amorphous semiconductor thick film such as amorphous selenium that can be easily formed as a radiation-sensitive semiconductor film 51 is used, it is suitable for increasing the radiation detection surface area of an FPD (see Patent Document 1). ).

  At the time of radiation detection by the FPD of FIG. 13, a bias voltage supplied from a bias supply power source (not shown) is applied from the common electrode 52 to the semiconductor film 51 via a lead wire 54 for supplying a bias voltage. The charges generated by the semiconductor film 51 and collected by the individual electrodes with the incidence of radiation are taken out as a radiation detection signal for each individual electrode by a charge readout circuit including a capacitor, a switching element, and an electric wiring. That is, in the case of a direct conversion type radiation detector, each individual electrode formed in a two-dimensional matrix array in the effective pixel area SA is a pixel electrode corresponding to each pixel of the radiation image, and is effective. A radiation detection signal for creating a radiation image corresponding to the two-dimensional intensity distribution of the radiation projected on the pixel area SA can be extracted.

In the case of the FPD of FIG. 13, the radiation-sensitive semiconductor film 51, the common electrode 52, and the curable synthetic resin film 56 are sandwiched between an active matrix substrate 53 and an auxiliary plate 55 having the same thermal expansion coefficient. A structure that suppresses warpage due to change prevents the semiconductor film 51 from being deteriorated or damaged due to stress applied to the semiconductor film 51.
JP 2002-31144 A (pages 6 to 10, page 1)

  However, the conventional FPD has a problem that the stress applied to the radiation-sensitive semiconductor film 51 is not sufficiently reduced. The difference in thermal expansion coefficient between the radiation-sensitive semiconductor film 51 and the curable synthetic resin film 56 and the residual stress of the curable synthetic resin film 56 only by the sandwiching between the active matrix substrate 53 and the auxiliary plate 55 having the same thermal expansion coefficient. Therefore, it cannot be avoided that considerable stress is applied to the semiconductor film 51.

  If the film thickness of the curable synthetic resin film 56 is reduced, the stress applied to the semiconductor film 51 can be reduced. However, the curable synthetic resin film 56 prevents creeping discharge of the bias voltage in addition to the purpose of improving environmental resistance. If the film thickness of the curable synthetic resin film 56 is reduced, the function of preventing the creeping discharge of the bias voltage of the curable synthetic resin film 56 is lowered and the protective function cannot be achieved. become.

  The present invention has been made in view of such circumstances, and has a high pressure-resistant curable synthetic resin film without impairing the creeping discharge prevention function of the high-voltage curable synthetic resin film covering the radiation-sensitive semiconductor. An object of the present invention is to provide a flat panel radiation detector capable of sufficiently reducing the stress applied to the radiation-sensitive semiconductor layer due to the above.

  In order to achieve such an object, the present invention has the following configuration.

  That is, the invention described in claim 1 includes (a) a radiation-sensitive semiconductor layer that generates a charge upon incidence of radiation, and (b) a common that is formed on the surface of the semiconductor layer and applies a bias voltage to the semiconductor layer. (C) an active matrix substrate on which an electrode, (c) a semiconductor layer and a common electrode are stacked in that order, and a charge readout circuit for reading out charges generated in the semiconductor layer and individual electrodes for pixel electrodes are formed; A bias voltage feeding lead wire connected to the common electrode at a position outside the pixel region; (e) a high pressure-resistant curable synthetic resin film covering the semiconductor layer and the common electrode; and (f) curable synthesis. In a flat panel radiation detector, which is fixed on the front side of the resin film and has an insulating auxiliary plate having the same thermal expansion coefficient as that of the active matrix substrate, the high pressure-resistant curable synthetic resin film is And it is characterized in that it is thinner than the thickness of the portion where the thickness of the portion covering at least the effective pixel region covers the connection region of the lead wire for bias voltage supply.

  [Operation / Effect] When radiation is detected by the radiation detector according to the first aspect of the present invention, a bias voltage is applied from a common electrode to a radiation-sensitive semiconductor layer via a bias voltage feeding lead, and a detection target is detected. As the radiation is incident on the radiation-sensitive semiconductor layer, a charge as a radiation detection signal source is generated, and the charge generated in the radiation-sensitive semiconductor layer is generated by the charge readout circuit of the active matrix substrate via an individual electrode. It is taken out.

  On the other hand, in the flat panel radiation detector according to the first aspect of the present invention, a radiation-sensitive semiconductor layer and a common electrode that generate electric charges upon incidence of radiation, and a high-voltage curable synthetic resin film that covers the semiconductor layer and the common electrode However, since it is sandwiched between the active matrix substrate having the same thermal expansion coefficient and the insulating auxiliary plate, warpage due to temperature change can be suppressed. Further, the high pressure-resistant curable synthetic resin film is a film in a portion where the film thickness of the portion covering the effective pixel area having a large occupation ratio with respect to the film area of the curable synthetic resin film covers the connection region of the lead wire for supplying the bias voltage. Since the thickness of the curable synthetic resin film is smaller than that of the curable synthetic resin film, the stress applied to the radiation-sensitive semiconductor layer due to the curable synthetic resin film can be sufficiently reduced.

  On the other hand, since the film thickness of the portion covering the connection area of the lead wire for supplying the bias voltage is larger than the film thickness of the portion covering the effective pixel area, the creeping discharge prevention of the high voltage curable synthetic resin film is prevented. The decline in function can be suppressed.

  According to a second aspect of the present invention, in the flat panel radiation detector according to the first aspect, the high pressure-resistant curable synthetic resin film is formed of a corner region of the radiation-sensitive semiconductor layer in addition to the effective pixel region. The film thickness of the portion covering the thin film is also thinner than the film thickness of the portion covering the connection area of the bias voltage power supply lead wire.

  [Operation / Effect] In the case of the radiation detector of the invention of claim 2, the high pressure-resistant curable synthetic resin film is a radiation-sensitive semiconductor in which deformation stress due to temperature change is concentrated in addition to the portion covering the effective pixel region. The film thickness of the part covering the corner area of the layer is also thinner than the film thickness of the part covering the connection area of the lead wire for supplying the bias voltage, and the curable synthetic resin film is thin over a wider range. In addition, since the concentration of deformation stress in the corner region of the semiconductor layer can be alleviated, the stress applied to the radiation-sensitive semiconductor layer due to the curable synthetic resin film can be more sufficiently reduced.

  According to a third aspect of the present invention, in the flat panel radiation detector according to the second aspect, the high pressure-resistant curable synthetic resin film is on the surface of the radiation-sensitive semiconductor layer and is supplied with a bias voltage. The film thickness of the portion that covers the remaining area other than the effective pixel area and the corner area of the semiconductor layer, as well as the film thickness of the portion that covers the connection area of the lead wire for supplying the bias voltage Is thinner.

  [Operation / Effect] In the case of the radiation detector according to the third aspect of the present invention, all but the portion of the radiation-sensitive semiconductor layer except the portion where the high-voltage synthetic resin film covers the connection region of the lead wire for supplying the bias voltage is provided. Since the film thickness is thin and the curable synthetic resin film is thin over an even wider range, the stress on the radiation-sensitive semiconductor layer due to the curable synthetic resin film can be reduced. It will be extremely sufficient.

  According to a fourth aspect of the present invention, in the flat panel radiation detector according to any one of the first to third aspects, the connection region of the lead wire for supplying the bias voltage in the high pressure-resistant curable synthetic resin film is provided. The thickness of the thin film portion that is thinner than the covering portion is TA, and the thickness of the thick film portion that covers the connection region of the bias voltage feeding lead wire is ta, and 0.5 ta ≧ TA ≧ 0.1 ta. It is what is.

  [Operation / Effect] In the case of the radiation detector according to the invention of claim 4, the thin film portion of the high withstand voltage curable synthetic resin film is thinner than the portion covering the connection region of the lead wire for supplying the bias voltage. The film thickness is sufficiently thin, less than half the thickness of the thick film part that covers the connection area of the lead wire for supplying the bias voltage, so that it becomes a radiation-sensitive semiconductor layer due to the curable synthetic resin film. Such stress reduction is surely achieved, and a thickness of 1/10 or more of the thickness of the portion covering the connection region of the lead wire for supplying the bias voltage is always ensured. Improvements are also certainly achieved.

  In the case of the flat panel radiation detector of the present invention, a radiation-sensitive semiconductor layer and a common electrode that generate electric charges upon incidence of radiation, and a high pressure-resistant curable synthetic resin film covering the semiconductor layer and the common electrode, Since it is sandwiched between the active matrix substrate having the same thermal expansion coefficient and the insulating auxiliary plate, warpage due to temperature change can be suppressed. Further, the high pressure-resistant curable synthetic resin film is a film in a portion where the film thickness of the portion covering the effective pixel area having a large occupation ratio with respect to the film area of the curable synthetic resin film covers the connection region of the lead wire for supplying the bias voltage. Since the thickness of the curable synthetic resin film is smaller than that of the curable synthetic resin film, the stress applied to the radiation-sensitive semiconductor layer due to the curable synthetic resin film can be sufficiently reduced.

  Conversely, the thickness of the portion covering the connection area of the lead wire for supplying the bias voltage is thicker than the thickness of the portion covering the effective pixel area. Reduction of the prevention function can be suppressed. Therefore, according to the flat panel radiation detector of the present invention, the high pressure-resistant curable synthetic resin film covering the radiation-sensitive semiconductor layer without damaging the creeping discharge preventing function of the high-voltage curable synthetic resin film is caused. Thus, the stress applied to the radiation-sensitive semiconductor layer can be sufficiently reduced.

  Example 1 of a flat panel radiation detector (hereinafter abbreviated as “FPD” where appropriate) according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration of a main part of a direct conversion type FPD according to Example 1, and FIG. 2 is a high-voltage curable synthetic resin film covering a radiation-sensitive semiconductor layer and a common electrode in the FPD of Example 1. FIG. 3 is a block diagram showing an electric circuit around the active matrix substrate of the FPD of Example 1. FIG. 4 is a cross-sectional view schematically showing the configuration of the active matrix substrate of the FPD of Example 1. FIG. FIG. 3 is an electrical equivalent circuit diagram of one radiation detection unit in the FPD according to the first embodiment.

  As shown in FIGS. 1 to 4, the FPD of Example 1 is made of a radiation sensitive semiconductor film 1 that generates charges by radiation (for example, X-rays), and a metal thin film that applies a bias voltage to the semiconductor film 1. The common electrode 2 is laminated on the active matrix substrate 3 in that order. The active matrix substrate 3 is formed with a charge readout circuit 6 for reading out the charges generated in the semiconductor film 1, and individual electrodes 5 for pixel electrodes are formed on the surface in a two-dimensional matrix arrangement in the effective pixel area SA. Yes. A bias voltage feed lead 4 is connected to the common electrode 2 at a position outside the effective pixel area SA. The semiconductor film 1 and the common electrode 2 are covered with a high pressure curable synthetic resin film 8 as a protective mold. An insulating auxiliary plate 7 having a thermal expansion coefficient similar to that of the active matrix substrate 3 is fixed to the front side of the curable synthetic resin film 8.

  The radiation-sensitive semiconductor film 1 has a three-layer structure including a thick film layer 1A and carrier-selective intermediate layers 1a and 1b disposed on the front and back surfaces of the thick film layer 1A, respectively. The intermediate layer 1a on the common electrode 2 side and the carrier-selective intermediate layer 1b on the individual electrode 5 side are formed of a carrier-selective high-resistance thin film.

  For the thick film layer 1A of the semiconductor film 1, an amorphous semiconductor film such as amorphous selenium (a-Se) or a compound semiconductor film such as CdZnTe is used. The thickness of the thick film layer 1A is usually about 0.5 mm to 1.5 mm.

As the intermediate layers 1a and 1b of the semiconductor film 1, an amorphous selenium thin film doped with Na, Cl, As, Te, or the like, or a compound semiconductor thin film such as Sb ₂ S ₃ or CdS is used. The thickness of the intermediate layers 1a and 1b is usually about 0.01 μm to 10 μm. In the case of the radiation-sensitive semiconductor film 1, the carrier-selective intermediate layers 1a and 1b are not necessarily provided, and one or both of the intermediate layers 1a and 1b may be omitted.

  The charge readout circuit 6 disposed on the active matrix substrate 3 includes a capacitor 6A, a TFT (thin film field effect transistor) 6B as a switching element, and electrical wirings 6a and 6b. One capacitor is provided for each individual electrode 5. 6A and one TFT 6B are provided. In addition to the gate driver 9, the charge voltage conversion amplifier 10 and the multiplexer 11, an A / D converter 12 is provided as a separate device separately from the active matrix substrate 3 in the subsequent stage of the charge readout circuit 6 of the active matrix substrate 3. Deployed and connected externally.

  In the radiation detection by the FPD of the first embodiment, a bias voltage of about several kilovolts to several tens of kilovolts output from the bias supply power source is applied to the radiation-sensitive type from the common electrode 2 via the lead wire 4 for supplying the bias voltage. It is given to the semiconductor film 1. Charges are generated in the semiconductor film 1 as the radiation to be detected is incident, and the charges generated in the semiconductor film 1 (specifically, the charges are induced in the individual electrodes 5 by moving to the individual electrodes 5). Collected for each individual electrode 5. The charges collected by each individual electrode 5 are taken out as a radiation detection signal for each individual electrode 5 by the charge readout circuit 6 of the active matrix substrate 3 or the like.

  Specifically, the readout signal is sequentially given from the gate driver 9 to the gate of each TFT 6B via the electrical wiring 6a, and at the same time, the electrical wiring 6b connected to the source of each TFT 6B to which the readout signal is given is connected to the multiplexer 11. Are connected in order. As a result, the charge accumulated in the capacitor 6A is amplified by the charge-voltage conversion type amplifier 10 from the TFT 6B via the electric wiring 6b, and then the A / D converter 12 as a radiation detection signal for each individual electrode 5 by the multiplexer 11. To be digitized. Note that the A / D converters 12 may be connected to all the charge-voltage conversion amplifiers 10 without using the multiplexer 11. If the FPD of the first embodiment is installed in, for example, an X-ray fluoroscopic apparatus, the radiation detection signal sent from the FPD of the first embodiment is finished into a two-dimensional X-ray fluoroscopic image or the like after the FPD. It is done.

  That is, in the FPD of the first embodiment, each individual electrode 5 in the two-dimensional matrix array is a pixel electrode corresponding to each pixel of the radiation image, and the two-dimensional intensity of radiation projected on the effective pixel area SA. This is a two-dimensional array type radiation detector capable of extracting a radiation detection signal capable of creating a radiation image corresponding to the distribution. In addition, in the FPD of the first embodiment, the radiation detection unit (radiation detection element) of the equivalent circuit shown in FIG. 5 is deployed and arranged in a two-dimensional matrix along vertical and horizontal grid lines in the effective image area SA. It is what.

  As a base material of the active matrix substrate 3, for example, a glass substrate is used. As the insulating auxiliary plate 7 having the same thermal expansion coefficient as that of the active matrix substrate 3, for example, a Pyrex glass substrate or a quartz glass substrate is used. The thickness of the glass substrate of the active matrix substrate 3 and the glass substrate of the auxiliary plate 7 is, for example, about 0.5 mm to 1.5 mm.

  In the case of Example 1, the high pressure-resistant curable synthetic resin film 8 is obtained by assembling the auxiliary plate 7 on the active matrix substrate 3 side through the frame frame spacer material 13 such as ABS resin, and the active matrix substrate 3. The auxiliary plate 7 is formed by bonding and fixing the auxiliary plate 7 by injecting and curing a liquid room temperature curable resin composition between the auxiliary plates 7. For the curable synthetic resin film 8, for example, a room temperature curable epoxy resin or the like is used as an appropriate resin material.

  In the case of the FPD of Example 1, the high pressure-resistant curable synthetic resin film 8 as the protective mold coating has a thin film portion 8A covering the effective pixel area SA as shown in FIG. As described above, the structure is characterized in that it is thinner than the thickness of the thick film portion 8a covering the periphery of the effective pixel area SA including the connection area of the lead wire 4 for supplying the bias voltage. In the case of Example 1, the high pressure-resistant curable synthetic resin film 8 having the thin film portion 8A and the thick film portion 8a is specifically formed as follows.

  The auxiliary plate 7 has a configuration in which the thin film piece 7A facing the effective pixel area SA is bonded and fixed to the back surface of the thick film piece 7a facing the area surrounding the effective pixel area SA on the peripheral surface. When the auxiliary plate 7 is assembled to the thin film piece 7A, the gap between the semiconductor film 1 side and the thin film piece 7A and the gap between the semiconductor film 1 side and the thick film piece 7a are equal to the thickness of the thin film piece 7A. Only a difference occurs.

  Therefore, when a liquid room temperature curable resin composition is injected and cured between the active matrix substrate 3 and the auxiliary plate 7, a gap difference between the thin film piece 7A and the thick film piece 7a with respect to the semiconductor film 1 side is generated. Accordingly, the thin film piece 7A becomes a thin film portion 8A, the thick film piece 7a has a thick film portion 8a, and the thin film portion 8A has a thickness corresponding to the thickness of the thin film piece 7A. A thin curable synthetic resin film 8 is formed. The auxiliary plate 7 does not have to be a two-piece type of the thin film piece 7A and the thick film piece 7a, and may be a one-piece type in which the thin film piece 7A and the thick film piece 7a are completely integrated from the beginning.

  In the high pressure-resistant curable synthetic resin film 8, the relationship of 0.5 ta ≧ TA ≧ 0.1 ta is assumed, where TA is the thickness of the thin film portion 8A and ta is the thickness of the portion covering the connection region of the thick film portion 8a. It is in. The film thickness TA of the thin film portion 8A is usually in the range of 0.1 mm to 0.5 mm, and the film thickness ta of the thick film portion 8a is usually in the range of 1 mm to 2 mm.

  In the case of the FPD according to the first embodiment having the above-described configuration, the radiation-sensitive semiconductor film 1 and the common electrode 2 that generate charges by the incidence of radiation, and the high withstand pressure curable property that covers the semiconductor film 1 and the common electrode 2. Since the synthetic resin film 8 is sandwiched between the active matrix substrate 3 and the insulating auxiliary plate 7 having the same thermal expansion coefficient, warpage due to temperature change can be suppressed. Further, in the curable synthetic resin film 8, the thickness of the thin film portion 8A covering the effective pixel area SA having a large occupation ratio with respect to the film area of the curable synthetic resin film covers the connection area of the lead wire 4 for supplying the bias voltage. Since the film thickness of the curable synthetic resin film 8 is smaller than that of the film portion 8a, the film thickness of the curable synthetic resin film 8 is reduced over a wide range, so that the radiation-sensitive semiconductor film 1 is formed due to the curable synthetic resin film 8. Such stress can be sufficiently reduced.

  On the other hand, since the film thickness of the thick film portion 8a covering the connection region of the lead wire 4 for supplying the bias voltage is thicker than the film thickness of the thin film portion 8A covering the effective pixel region SA, high withstand voltage curing is achieved. The deterioration of the creeping discharge preventing function of the conductive synthetic resin film 8 can be suppressed. Further, since the thick film portion 8a covers the entire periphery of the semiconductor film 1 where creeping discharge is likely to occur, the reduction of the creeping discharge preventing function is sufficiently suppressed.

  Further, in the case of the FPD of Example 1, the film thickness TA of the thin film portion 8A, which is thinner than the thick film portion 8a covering the connection region of the bias voltage feeding lead 4 in the high breakdown voltage synthetic resin film 8. However, since the thickness is sufficiently thin, that is, less than half of the film thickness ta of the thick film portion 8a, the stress applied to the radiation-sensitive semiconductor film 1 due to the curable synthetic resin film 8 can be reliably reduced. Since a thickness of 1/10 or more of the film thickness ta of the thick film portion 8a is always ensured, improvement in environmental resistance by the curable synthetic resin film 8 is also achieved reliably.

  The FPD of Example 2 will be described with reference to the drawings. FIG. 6 is a cross-sectional view illustrating a configuration of a main part of the FPD according to the second embodiment. As shown in FIG. 6, the FPD of the second embodiment includes a single insulating auxiliary plate 14 having a thermal expansion coefficient comparable to that of the active matrix substrate 3 and an inward flange that protrudes toward the effective pixel area SA. Since it is substantially the same as the FPD of the first embodiment except that it includes the frame frame spacer material 15 such as ABS resin having the portion 15A along the inner periphery of the upper end, the points in common with the first embodiment Description is omitted, and only differences are described.

  In the case of the FPD of Example 2, the high breakdown voltage synthetic resin film 8 is formed as follows. The auxiliary plate 14 is fixed in advance to the back surface of the inner flange portion 15 </ b> A of the frame frame spacer material 15 and assembled together with the frame frame spacer material 15 on the active matrix substrate 3 side. As a result, a difference corresponding to the thickness of the auxiliary plate 14 is generated in the gap between the semiconductor film 1 side and the auxiliary plate 14 and in the gap between the semiconductor film 1 side and the inward flange portion 15A. When the liquid room-temperature curable resin composition is injected and cured in this state, the auxiliary plate 14 has a thin film portion 8A due to a gap difference between the auxiliary plate 14 and the inward flange portion 15A with respect to the semiconductor film 1 side. Thus, the inner flange portion 15A is a thick film portion 8a, and the curable synthetic resin film 8 is formed so that the thin film portion 8A is thinner than the thick film portion 8a by an amount corresponding to the thickness of the auxiliary plate 14.

  The FPD of Example 3 will be described with reference to the drawings. FIG. 7 is a plan view showing a high pressure-resistant curable synthetic resin film 8 covering the radiation-sensitive semiconductor film 1 and the common electrode 2 in the FPD of the third embodiment. In the FPD of the third embodiment, the high breakdown voltage synthetic resin film 8 has a thin film portion 8B covering the effective pixel area SA and the corner area SB of the radiation-sensitive semiconductor film 1 so that the thickness of the lead wire for supplying bias voltage is the same. Since it is substantially the same as the FPD of the first embodiment except that it is thinner than the film thickness of the thick film portion 8b covering the region including the connection region, the description of the points common to the first embodiment is omitted. Only the differences will be described.

  In the case of the FPD of Example 3, the insulating auxiliary plate 16 having the same thermal expansion coefficient as that of the active matrix substrate 3 has a thin film piece 16A and a semiconductor film facing the effective pixel region SA as shown in FIG. Four thin film pieces 16B having a square shape facing one corner region SB and a thick film piece 16a facing the region including the connection region of the lead wire 4 for supplying bias voltage are formed. When the auxiliary plate 16 is assembled on the active matrix substrate 3 side and the liquid room temperature curable resin composition is injected and cured, the thin film pieces 16A and 16B become the thin film portions 8B, and the thick film pieces 16a However, a thick film portion 8b is formed, and a curable synthetic resin film 8 is formed in which the thin film portion 8B is thinner than the thick film portion 8b by an amount corresponding to the thickness of the thin film pieces 16A and 16B.

  According to the FPD of Example 3, the thickness of the curable synthetic resin film 8 is reduced over a wider range, and the concentration of deformation stress in the corner region SB of the semiconductor film 1 can be reduced. The stress applied to the radiation-sensitive semiconductor film 1 due to the resin film 8 can be more sufficiently reduced.

  The FPD of Example 4 will be described with reference to the drawings. FIG. 9 is a plan view showing a high pressure-resistant curable synthetic resin film 8 covering the radiation-sensitive semiconductor film 1 and the common electrode 2 in the FPD of Example 4. The FPD of Example 4 also has a circular shape in which the film thickness of the thin film portion 8C covering the effective pixel area SA and the corner area SB of the radiation-sensitive semiconductor film 1 covers the area including the connection area of the lead wire for supplying the bias voltage. It is thinner than the thickness of the thick film portion 8c. In addition, the thin film portion 8C of the curable synthetic resin film 8 has a substantially triangular shape at the corner region SB, and the thin film portion 8C of the curable synthetic resin film 8 has a rectangular shape at the corner region SB. Since this is substantially the same as the FPD of the first embodiment, the description of the points in common with the third embodiment will be omitted, and only the differences will be described.

  In the case of the FPD of Example 4, the insulating auxiliary plate 17 having a thermal expansion coefficient comparable to that of the active matrix substrate 3 includes a thin film piece 17A and a semiconductor film facing the effective pixel area SA, as shown in FIG. The four thin film pieces 17B having a substantially triangular plane shape facing one corner region SB and the thick film piece 17a facing the region including the connection region of the lead wire 4 for supplying the bias voltage are formed. As a result, when the liquid room temperature curable resin composition is injected and cured, the thin film pieces 17A and 17B become the thin film portion 8C, and the thick film piece 17a becomes the thick film portion 8c. The portion 8C has a substantially triangular shape at the corner region SB.

  The FPD of Example 5 will be described with reference to the drawings. FIG. 11 is a plan view showing a high pressure-resistant curable synthetic resin film 8 covering the radiation-sensitive semiconductor film 1 and the common electrode 2 in the FPD of the fifth embodiment. In addition to the effective pixel area SA and the corner area SB of the semiconductor film 1, the FPD of the fifth embodiment is further on the surface of the radiation sensitive semiconductor film 1 and outside the connection area of the lead wire 4 for supplying bias voltage. The film thickness of the thin film portion 8D that covers the remaining area other than the effective pixel area SA and the corner area SB of the semiconductor film is the film thickness of the thick film portion 8d that covers the connection area of the lead wire 4 for supplying the bias voltage. Since it is substantially the same as the FPD of the first embodiment except that the thickness is thinner, the description of the points in common with the first embodiment will be omitted, and only the points of difference will be described.

  In the case of the FPD of the fifth embodiment, the insulating auxiliary plate 18 having the same thermal expansion coefficient as that of the active matrix substrate 3 is formed in the effective pixel area SA, the corner area SB, and other remaining areas as shown in FIG. It consists of a thin film piece 18A facing and a thick film piece 18a facing the connection region of the lead wire 4 for supplying bias voltage. When the auxiliary plate 18 is assembled on the side of the active matrix substrate 3 and the liquid room temperature curable resin composition is injected and cured, the thin film piece 18A becomes the thin film portion 8D and the thick film piece 18a becomes the thick film. The thin film portion 8D is formed with the curable synthetic resin film 8 that is thinner than the thick film piece 8d by an amount corresponding to the thickness of the thin film piece 18A.

  According to the FPD of Example 5, the curable synthetic resin film 8 is thin on the surface of the radiation-sensitive semiconductor film 1 except for the portion covering the connection region of the lead wire 4 for supplying the bias voltage. Since the curable synthetic resin film 8 is thin over a wider range, the stress on the radiation-sensitive semiconductor film 1 due to the curable synthetic resin film 8 is extremely reduced. It will be enough.

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

  (1) In the FPDs of the first to fifth embodiments, the A / D converter 12 is provided in addition to the gate driver 9, the charge-voltage conversion amplifier 10, and the multiplexer 11. However, the gate driver 9, the charge-voltage conversion amplifier 10. An FPD having the same configuration as that of each of the first to fifth embodiments except that some or all of the multiplexer 11 and the A / D converter 12 are not provided is also given as a modified example.

  (2) In the FPDs of Examples 1 to 5, the radiation-sensitive semiconductor layer was a film body. However, in the case of the FPD of the present invention, a radiation-sensitive semiconductor crystal was thinly sliced as the radiation-sensitive semiconductor layer. It may be a thin plate.

  (3) The FPDs of Examples 1 to 5 can be used not only for medical use but also for industrial use or nuclear power use.

FIG. 3 is a cross-sectional view illustrating a main configuration of the FPD according to the first embodiment. 3 is a plan view showing a high pressure-resistant curable synthetic resin film in the FPD of Example 1. FIG. FIG. 3 is a block diagram illustrating an electric circuit around an active matrix substrate of the FPD according to the first embodiment. FIG. 3 is a schematic cross-sectional view showing a configuration of an active matrix substrate of the FPD of Example 1. 3 is an electrical equivalent circuit diagram of one radiation detection unit in the FPD of Embodiment 1. FIG. FIG. 6 is a cross-sectional view illustrating a main configuration of an FPD according to a second embodiment. 6 is a plan view showing a high pressure-resistant curable synthetic resin film in the FPD of Example 3. FIG. 6 is a plan view showing an auxiliary plate in the FPD of Example 3. FIG. 6 is a plan view showing a high pressure-resistant curable synthetic resin film in the FPD of Example 4. FIG. 6 is a plan view showing an auxiliary plate in an FPD of Example 4. FIG. 6 is a plan view showing a high pressure-resistant curable synthetic resin film in the FPD of Example 5. FIG. 10 is a plan view showing an auxiliary plate in the FPD of Example 5. FIG. It is sectional drawing which shows the structure of the conventional FPD.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Radiation sensitive semiconductor film 2 ... Common electrode 3 ... Active matrix substrate 4 ... Lead wire 5 ... Individual electrode 6 ... Charge readout circuit 7 ... Auxiliary plate 8 ... Curable synthetic resin film 8A-8D ... Thin film part 8a-8d ... thick film part 15-18 ... auxiliary plate SA ... effective pixel area SB ... corner area (semiconductor film) TA ... film thickness (thin film part) ta ... film thickness (thick film part)

Claims (4)

  (A) a radiation-sensitive semiconductor layer that generates a 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; and (c) a semiconductor layer and a common electrode. And an active matrix substrate on which a charge readout circuit for reading out charges generated in the semiconductor layer and individual electrodes for pixel electrodes are formed, and (d) a common electrode at a position outside the effective pixel region. An active matrix substrate fixed to the front side of the lead wire for bias voltage supply to be connected; (e) a high pressure-resistant curable synthetic resin film covering the semiconductor layer and the common electrode; and (f) a curable synthetic resin film. In a flat panel radiation detector having an insulating auxiliary plate having a thermal expansion coefficient comparable to that of the first embodiment, the high pressure-resistant curable synthetic resin film covers at least the effective pixel region. Flat panel radiation detector, characterized in that the film thickness is thinner than the thickness of the portion covering the connection region of the lead wire for bias voltage supply.   2. The flat panel radiation detector according to claim 1, wherein the high pressure-resistant curable synthetic resin film has a bias voltage supply in addition to an effective pixel region and a film thickness of a portion covering a corner region of the radiation-sensitive semiconductor layer. A flat panel radiation detector that is thinner than the thickness of the part covering the connection area of the lead wire for use.   3. The flat panel radiation detector according to claim 2, wherein the high pressure-resistant curable synthetic resin film is on the surface of the radiation-sensitive semiconductor layer and outside the connection region of the lead wire for supplying bias voltage. In addition, the thickness of the portion covering the effective pixel region and the remaining region other than the corner region of the semiconductor layer is also thinner than the thickness of the portion covering the connection region of the lead wire for bias voltage supply. vessel. 4. The flat panel radiation detector according to claim 1, wherein the film thickness is thinner than a portion of the high pressure-resistant curable synthetic resin film that covers the connection region of the lead wire for supplying the bias voltage. A flat panel radiation detector in which 0.5 ta ≧ TA ≧ 0.1 ta, where TA is the thickness of the thin film portion and ta is the thickness of the thick film portion that covers the connection region of the lead wire for supplying the bias voltage.

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