JP2010237162A - Radiation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent damages in a substrate-end part, at a side in which a connection terminal is disposed. <P>SOLUTION: An opposite substrate 40 disposed opposite a TFT substrate 16 across a radiation conversion layer 50 therebetween covers the substrate end part 16A, in plan view at the side in which the connection terminals 38, 39 are disposed. Accordingly, even when the substrate end part 16A is to be deformed, the substrate end part 16A, the connection terminals 38, 39, and wiring 35, 37 connected to the connection terminals 38, 39 abut against the opposite substrate 40 to keep the deformation of the substrate end part 16A limited, and damages to of the substrate end part 16A are prevented. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radiation detection apparatus that detects radiation.

  As a radiation detection apparatus for detecting radiation, a radiation detection panel using a TFT array is known. In a radiation detection panel using a TFT array, a scintillator layer that fluoresces when a radiation is incident and a photoconductive layer that generates a charge when the radiation is incident are formed on a TFT array substrate on which the TFT array is formed. The scintillator layer and the photoconductive layer are sealed with a sealing layer such as a glass cover or a resin.

  Unlike the case of using a CMOS sensor, the configuration for detecting radiation by TFT requires at least a gate line for driving the TFT and a signal line for reading a signal from the TFT, and for connecting these externally. It is necessary to arrange the connection terminals on the TFT array substrate.

  As described above, since it is necessary to make an external connection with the connection terminal, as shown in Patent Document 1 and Patent Document 2, the TFT array substrate has a substrate end portion on the side where the connection terminal is arranged, a scintillator layer or an optical element. It is comprised so that it may protrude outside a conductive layer or a sealing layer.

JP 2001-148475 A JP 2006-78471 A

  By the way, the TFT array substrate is generally formed of a thin glass substrate which is inexpensive. For this reason, as shown in Patent Document 1 and Patent Document 2, in the configuration in which the substrate end portion on the side where the connection terminals are arranged projects outside the scintillator layer, the photoconductive layer, or the sealing layer, the radiation detection panel is When subjected to vibration or impact, cracks and chipping occur at the edge of the substrate, leading to breakage of the connection terminals.

  In view of the above fact, an object of the present invention is to provide a radiation detection apparatus capable of suppressing breakage at a substrate end portion on the side where a connection terminal is disposed.

  According to a first aspect of the present invention, there is provided a radiation detection apparatus, comprising: a TFT substrate having a TFT switch element formed on an insulating substrate; the TFT substrate disposed on the TFT substrate; and converting radiation into charges read by the switch element. Alternatively, a radiation conversion layer that converts radiation into light that is converted into electric charges read by the switch element, and at least a part of the peripheral edge of the TFT substrate in plan view, the switch element being connected to an external circuit And a counter substrate that is disposed to face the TFT substrate with the radiation conversion layer interposed therebetween and covers a substrate end portion on the side where the connection terminal is disposed in a plan view. .

  According to this configuration, the radiation conversion layer converts radiation into charges or converts radiation into light. When converted into light, this light is converted into electric charge. The converted charge is read out by the switch element of the TFT substrate, and radiation detection is performed.

  Here, in the configuration of the first aspect of the present invention, the counter substrate disposed opposite to the TFT substrate with the radiation conversion layer interposed therebetween is arranged such that the substrate end on the side where the connection terminal is disposed is viewed in plan view. Covering.

  For this reason, even when the substrate end portion is about to deform, the substrate end portion, the connection terminal, the wiring connected to the connection terminal, etc. abut against the counter substrate, and the deformation of the substrate end portion is restricted. Damage can be suppressed.

  The radiation detection apparatus according to claim 2 of the present invention is the radiation detection apparatus according to claim 1, wherein the radiation conversion layer extends to a side region of the connection terminal toward a peripheral edge of the TFT substrate in plan view. .

  According to this configuration, the radiation conversion layer extends to the side region of the connection terminal, so that the peripheral portion of the connection terminal is reinforced and damage to the substrate end on the side where the connection terminal is disposed can be suppressed.

  According to a third aspect of the present invention, in the configuration of the first or second aspect, the radiation detection apparatus is sandwiched between the substrate end portion and the counter substrate, and is in a region where the radiation conversion layer is not disposed. A provided spacer is provided.

  According to this configuration, the spacer sandwiched between the substrate end and the counter substrate can restrict the deformation of the substrate end and suppress the breakage of the substrate end.

  A radiation detection apparatus according to a fourth aspect of the present invention is the radiation detection apparatus according to any one of the first to third aspects, wherein the radiation conversion layer is not disposed between the substrate end and the counter substrate. A resin material that fills the region and seals the connection terminal is provided.

  According to this configuration, the resin material between the substrate end and the counter substrate can restrict the deformation of the substrate end and suppress the breakage of the substrate end.

  According to a fifth aspect of the present invention, in the configuration of any one of the first to fourth aspects, a radiation is incident on the radiation conversion layer through the TFT substrate.

  According to this configuration, since the counter substrate does not hinder radiation incidence, the degree of freedom in selecting the material of the counter substrate is increased. For this reason, it is possible to select a material having high rigidity as the counter substrate as compared with the configuration in which radiation is incident from the counter substrate side.

  Since this invention set it as the said structure, it can suppress the damage in the board | substrate edge part by which the connection terminal is arrange | positioned.

FIG. 1 is a schematic side view schematically showing a configuration of a radiation detection apparatus according to an indirect conversion method. FIG. 2 is a schematic plan view schematically showing the configuration of the radiation detection apparatus according to the present embodiment. FIG. 3 is a schematic side view schematically showing the configuration of the radiation detection apparatus according to the direct conversion method. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2 showing a simplified overall configuration of the radiation detection apparatus according to the present embodiment. FIG. 5 is a schematic plan view showing the positional relationship between the counter substrate and the TFT substrate according to the present embodiment. FIG. 6 is a cross-sectional view showing a modification in which the TFT substrate and the counter substrate according to this embodiment are supported by a support member. FIG. 7 is a cross-sectional view showing a modification in which the radiation conversion layer according to the present embodiment is extended to the side region of the connection terminal 38. FIG. 8 is a cross-sectional view showing a modification in which a spacer is disposed between the substrate end of the TFT substrate according to the present embodiment and the counter substrate. FIG. 9 is a cross-sectional view showing a modification in which a resin material is filled between the substrate end portion of the TFT substrate and the counter substrate according to this embodiment.

Below, an example of an embodiment concerning the present invention is described based on a drawing.
(Configuration of radiation detection apparatus according to the present embodiment)
First, the configuration of the radiation detection apparatus according to the present embodiment will be described. FIG. 1 is a schematic side view schematically showing a configuration of a radiation detection apparatus according to an indirect conversion method. FIG. 2 is a schematic plan view schematically showing the configuration of the radiation detection apparatus according to the present embodiment. FIG. 3 is a schematic side view schematically showing the configuration of the radiation detection apparatus according to the direct conversion method.

  As shown in FIG. 1, the radiation detection apparatus 10 includes a TFT substrate 16 in which a switch element 28 made of a thin film transistor (TFT) is formed on an insulating substrate 12.

  A scintillator layer 18 that converts incident radiation into light is formed on the TFT substrate 16 as an example of a radiation conversion layer that converts incident radiation.

As the scintillator layer 18, for example, CsI: Tl, GOS (Gd ₂ O ₂ S: Tb) can be used. Note that the scintillator layer 18 is not limited to these materials.

  As the insulating substrate 12, for example, a glass substrate, various ceramic substrates, or a resin substrate can be used. The insulating substrate 12 is not limited to these materials.

  Between the scintillator layer 18 and the TFT substrate 16, a photoconductive layer 20 that generates charges when light converted by the scintillator layer 18 is incident is disposed. A bias electrode 22 for applying a bias voltage to the photoconductive layer 20 is formed on the surface of the photoconductive layer 20 on the scintillator layer 18 side.

  On the TFT substrate 16, a charge collecting electrode 24 that collects charges generated in the photoconductive layer 20 is formed. In the TFT substrate 16, the charges collected by the charge collection electrodes 24 are read out by the switch element 28.

  The charge collection electrode 24 is two-dimensionally arranged on the TFT substrate 16, and correspondingly, the switch element 28 is two-dimensionally arranged on the insulating substrate 12 as shown in FIG. 2.

  Further, the TFT substrate 16 is extended in a certain direction (row direction) and a plurality of gate lines 30 for turning on and off each switch element 28, and in a direction orthogonal to the gate lines 30 (column direction). A plurality of signal lines (data lines) 32 for reading out charges through the switch element 28 in the on state are provided.

  A flattening layer 23 for flattening the TFT substrate 16 is formed on the TFT substrate 16. An adhesive layer 25 for bonding the scintillator layer 18 to the TFT substrate 16 is formed between the TFT substrate 16 and the scintillator layer 18 and on the planarizing layer 23.

  The TFT substrate 16 has a quadrilateral shape having four sides on the outer edge in plan view. Specifically, it is formed in a rectangular shape.

  A connection terminal 38 to which individual gate lines 30 are connected is arranged on one side of the peripheral edge of the TFT substrate 16 in plan view. The connection terminal 38 is connected to a gate line driver 34 as an external circuit via a wiring 35.

In addition, a connection terminal 39 to which individual signal lines 32 are connected is arranged on one side of the peripheral edge of the TFT substrate 16. The connection terminal 39 is connected to a signal processing unit 36 as an external circuit through a wiring 37. One side where the connection terminal 39 is arranged is positioned in a direction perpendicular to the one side where the connection terminal 38 is arranged.
Note that the connection terminal 38 and the connection terminal 39 may be arranged on opposite sides. Further, the connection terminal 38 and the connection terminal 39 may be arranged on the same side. Further, each of the connection terminal 38 and the connection terminal 39 may be arranged with respect to a plurality of sides.

  Each switch element 28 is sequentially turned on in a row unit by a signal supplied from the gate line driver 34 via the gate line 30, and the charges read by the switch elements 28 that are turned on are signal lines as charge signals. 32 is transmitted and input to the signal processing unit 36. Therefore, the charges are sequentially read out in units of rows, and a two-dimensional radiation image can be acquired.

  The radiation detection apparatus 10 described above is an indirect conversion method in which radiation is temporarily converted into light, and the light is converted into electric charge to detect the radiation. However, as the radiation detection apparatus, the radiation is directly charged. It may be a direct conversion method for converting to.

  In the direct conversion type radiation detection apparatus, as shown in FIG. 3, as an example of a radiation conversion layer that converts incident radiation, a photoconductive layer 48 that converts incident radiation into electric charges is formed on the TFT substrate 16. Is formed.

As the photoconductive layer 48, amorphous Se, Bi ₁₂ MO ₂₀ (M: Ti, Si, Ge), Bi ₄ M ₃ O ₁₂ (M: Ti, Si, Ge), Bi ₂ O ₃ , BiMO ₄ (M: Nb, Ta, V), Bi ₂ WO ₆ , Bi ₂₄ B ₂ O ₃₉ , ZnO, ZnS, ZnSe, ZnTe, MNbO ₃ (M: Li, Na, K), PbO, HgI ₂ , PbI ₂ , CdS, CdSe , CdTe, BiI ₃ , GaAs, etc. are used as the main component, but they have high dark resistance, good photoconductivity against X-ray irradiation, and low temperature by vacuum deposition. An amorphous material capable of forming a large area is preferred.

  On the photoconductive layer 48, a bias electrode 52 that is formed on the surface side of the photoconductive layer 48 and applies a bias voltage to the photoconductive layer 48 is formed.

  In the direct conversion type radiation detection apparatus, the charge collection electrode 24 that collects the charges generated in the photoconductive layer 48 is formed on the TFT substrate 16 as in the indirect conversion type radiation detection apparatus.

  In addition, the TFT substrate 16 in the direct conversion type radiation detection apparatus includes a charge storage capacitor 26 that stores the charges collected by the charge collection electrodes 24. The charge accumulated in each charge storage capacitor 26 is read out by the switch element 28.

(Configuration for reinforcing the substrate end 16A of the TFT substrate 16)
Next, a configuration for reinforcing the substrate end 16A on the side where the connection terminal 38 is arranged in the TFT substrate 16 will be described. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2 showing a simplified overall configuration of the radiation detection apparatus according to the present embodiment.

  This configuration can be applied to both indirect conversion method and direct conversion method radiation detection devices. The scintillator layer 18 in the indirect conversion method and the photoconductive layer 48 in the direct conversion method are collectively used as the radiation conversion layer 50. This will be described below.

  As shown in FIG. 4, the radiation detection apparatus 10 includes a counter substrate 40 disposed to face the TFT substrate 16 with the radiation conversion layer 50 interposed therebetween. The counter substrate 40 covers the substrate end 16A on the side where the connection terminals are disposed in a plan view. That is, when the radiation detection apparatus 10 is viewed from the direction of arrow A in FIG. 4, the counter substrate 40 overlaps the TFT substrate 16 as shown in FIG. 5A, and the TFT substrate 16 faces the surface of the counter substrate 40. It is within.

  In the present embodiment, as shown in FIG. 5A, the counter substrate 40 protrudes outward from the TFT substrate 16 at the substrate end 16A, and from the outer edge 16B of the substrate end 16A of the TFT substrate 16. The outer edge 40A is located outside. As shown in FIG. 5B, the outer edge 40A of the counter substrate 40 may coincide with the outer edge 16B of the substrate end portion 16A of the TFT substrate 16.

  Further, a gap is formed between the substrate end portion 16 </ b> A of the TFT substrate 16 and the counter substrate 40. A gap is also formed between the counter substrate 40 and the radiation conversion layer 50. The TFT substrate 16 and the counter substrate 40 are individually and independently supported in the radiation detection apparatus 10 by a support member (not shown).

  As described above, according to this configuration, the counter substrate 40 disposed opposite to the TFT substrate 16 with the radiation conversion layer 50 interposed therebetween is the substrate end 16A on the side where the connection terminals 38 and 39 are disposed. Since the circuit board is covered in plan view, even when the substrate end 16A is about to be deformed, the substrate end 16A, the connection terminals 38, 39, and the wirings 35, 37 connected to the connection terminals 38, 39 face each other. The deformation of the substrate end portion 16A is restricted by contacting the substrate 40, and damage to the substrate end portion 16A can be suppressed.

  In the present embodiment, radiation is incident on the radiation conversion layer 50 through the TFT substrate 16 from the TFT substrate 16 side. For this reason, in the case of irradiating radiation from a radiation source disposed above the apparatus, as shown in FIG. 4, the TFT substrate 16 is disposed on the upper side, and the radiation conversion layer 50 is disposed on the lower side. . As a result, the substrate end portion 16A is easily deformed by gravity. However, in the configuration of the present embodiment, the deformation of the substrate end portion 16A is restricted by the counter substrate 40, so that damage to the substrate end portion 16A is effectively suppressed. it can. As described above, the configuration of the present embodiment is particularly effective in a configuration in which radiation is incident on the radiation conversion layer 50 from the TFT substrate 16 side.

  A configuration in which radiation is incident from the radiation conversion layer 50 side without passing through the TFT substrate 16 may be employed.

  Further, the TFT substrate 16 and the counter substrate 40 may be supported by a support member 46 as shown in FIG. In the configuration shown in FIG. 6, the support member 46 is formed in a U shape (U shape) in a side view.

  The support member 46 includes a first plate 46A to which the counter substrate 40 is fixed, a second plate 46B to which the TFT substrate 16 is fixed, and a connecting plate that connects the first plate 46A and the second plate 46B. It is comprised with the body 46C. The first plate body 46A is disposed on the surface of the counter substrate 40 opposite to the TFT substrate 16 when viewed from the counter substrate 40, and supports the counter substrate 40.

  The second plate body 46B is disposed on the surface of the TFT substrate 16 opposite to the counter substrate 40 when viewed from the TFT substrate 16, and supports the TFT substrate 16. The support member 46 is fixed to a housing (not shown) of the radiation detection apparatus 10.

  Further, as shown in FIG. 7, the radiation conversion layer 50 may extend to the side region of the connection terminal 38 toward the outer end of the TFT substrate 16. Accordingly, the connection terminal 38 is surrounded by the radiation conversion layer 50 from three directions.

  According to the configuration shown in FIG. 7, the peripheral portions of the connection terminals 38 and 39 are reinforced, and the breakage of the substrate end portion 16A can be suppressed.

  Moreover, as shown in FIG. 8, the structure which provides the spacer 42 pinched | interposed between the board | substrate edge part 16A of the TFT substrate 16 and the opposing board | substrate 40 in the area | region where the radiation converting layer 50 is not arrange | positioned may be sufficient. . The spacer 42 is in contact with the TFT substrate 16 and the counter substrate 40, and fills the space between the TFT substrate 16 and the counter substrate 40.

  In the configuration shown in FIG. 8, the spacer 42 sandwiched between the substrate end portion 16A and the counter substrate 40 restricts deformation of the substrate end portion 16A and can suppress damage to the substrate end portion 16A.

  Further, as shown in FIG. 9, the resin material 44 that seals the connection terminals 38 and 39 is filled in a region between the substrate end portion 16A and the counter substrate 40 where the radiation conversion layer 50 is not disposed. It may be a configuration. The resin material 44 is in contact with the TFT substrate 16 and the counter substrate 40, and fills the space between the TFT substrate 16 and the counter substrate 40.

  In the configuration shown in FIG. 9, the resin material 44 between the substrate end portion 16A and the counter substrate 40 restricts deformation of the substrate end portion 16A, and can suppress damage to the substrate end portion 16A.

  The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made.

10 Radiation Detection Device 12 Insulating Substrate 16 TFT Substrate 16A Substrate End 18 Scintillator Layer (Radiation Conversion Layer)
28 switch element 38 connection terminal 39 connection terminal 40 counter substrate 42 spacer 44 resin material 48 photoconductive layer (radiation conversion layer)
50 Radiation conversion layer

Claims (5)

A TFT substrate in which a switch element made of TFT is formed on an insulating substrate;
A radiation conversion layer that is disposed on the TFT substrate and converts radiation into charges read out by the switch elements or converts radiation into light converted into charges read out by the switch elements;
A connection terminal disposed on at least a part of the peripheral edge of the TFT substrate in plan view, and for connecting the switch element to an external circuit;
A counter substrate disposed opposite to the TFT substrate with the radiation conversion layer interposed therebetween, and covering a substrate end on the side where the connection terminal is disposed in a plan view;
A radiation detection apparatus comprising:   The radiation detection apparatus according to claim 1, wherein the radiation conversion layer extends to a side region of the connection terminal toward a peripheral end of the TFT substrate in a plan view.   The radiation detection apparatus of Claim 1 or Claim 2 provided with the spacer provided in the area | region where the said radiation conversion layer is not pinched | interposed between the said board | substrate edge part and the said opposing board | substrate.   The resin material which fills the area | region where the said radiation conversion layer is not arrange | positioned between the said board | substrate edge part and the said opposing board | substrates, and seals the said connection terminal is given to any one of Claims 1-3. The radiation detection apparatus described.   The radiation detection apparatus according to claim 1, wherein radiation is incident on the radiation conversion layer through the TFT substrate.

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