JP5264291B2 - Radiation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stipulate the formation range of an organic layer and to improve the durability of a radiation detector. <P>SOLUTION: The outer edge of a hole injection inhibition layer 402 is positioned on the side of an image information acquisition area G by 1 mm from an extraction electrode 470, and is positioned between the area end G1 of the image information acquisition area G where image information is acquired and the extraction electrode 470. Thus, the hole injection inhibition layer 402 covers the image information acquisition area G of a photoconductive layer 404, the degradation of crystallization or the like in the image information acquisition area G of the photoconductive layer 404 is suppressed, and the durability as the radiation detector 400 is improved. Also, since the hole injection inhibition layer 402 does not cover the extraction electrode 470, the conduction defect of the extraction electrode 470 is prevented. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a radiation detector used in a medical X-ray imaging apparatus and the like, a method of manufacturing the radiation detector, a coating liquid used in the manufacturing method, and a method of manufacturing an organic polymer layer manufactured using the coating liquid About.

As a radiation detector, the technique disclosed in Patent Document 1 is known. In Patent Document 1, a suppression layer that suppresses interface crystallization of a recording photoconductive layer laminated between a first electrode and a recording photoconductive layer is moved to the first electrode when recording image information. Disclosed is a structure formed of an organic film (organic layer) that is insulative with respect to a charge having a polarity opposite to that of the charge and that is conductive with respect to a charge having the same polarity as the charge that moves to the first electrode ing. According to this configuration, it is possible to reduce the residual charge in the suppression layer caused by recording and reading of a radiation image with a large dose, and it is possible to prevent deterioration of sensitivity due to this residual charge, residual ghost image, and the like. .
JP 2004-165480 A

  However, Patent Document 1 does not describe the formation range of the organic layer, and it is unclear as to what range the organic layer should actually be formed.

  In view of the above facts, an object of the present invention is to improve the durability of the radiation detector by defining the formation range of the organic layer.

The radiation detector according to the first aspect includes a first electrode, a photoconductive layer that is formed in a wider area than the first electrode, generates a charge when irradiated with radiation carrying image information, and the photoconductive layer. A second electrode for collecting charges generated by the photoconductive layer; a second electrode for collecting charges generated by the photoconductive layer; and a side opposite to the side where the first electrode is provided with respect to the layer. An extraction electrode that extracts the charge from the second electrode to acquire information, an image information acquisition region end that is formed between the first electrode and the photoconductive layer, and from which the image information is acquired, and the extraction electrode And an organic polymer layer in which an outer edge portion is positioned between the two.

  According to this configuration, the photoconductive layer is irradiated with radiation carrying image information, and the photoconductive layer generates charges. The charge generated by the photoconductive layer is collected by the second electrode. The charge collected by the second electrode is extracted from the second electrode by the extraction electrode in order to acquire image information.

  The charge generated by the charge conversion layer includes not only the charge conversion layer directly generated but also the charge conversion layer indirectly generated, for example, corresponding to the charge directly generated by the charge conversion layer. It is a concept that includes generated charges.

Here, in the configuration of the first aspect , the organic polymer layer formed between the first electrode and the photoconductive layer has an outer edge portion of the image information acquisition region end where the image information is acquired, and the extraction electrode. Located between.

  As a result, the organic polymer layer covers the image information acquisition region of the photoconductive layer, so that deterioration such as crystallization in the image information acquisition region of the photoconductive layer can be suppressed, and durability as a radiation detector is improved. . Moreover, since the organic polymer layer does not cover the extraction electrode, it is possible to prevent a conduction failure of the extraction electrode.

The radiation detector according to the second aspect is characterized in that, in the configuration of the first aspect , the organic polymer layer has charge selectivity.

As described in the second embodiment , the organic polymer layer preferably has charge selectivity.

  Here, in the present invention, the organic polymer layer has charge selectivity when the organic polymer layer flows out of the first electrode with which the organic polymer layer is in contact (if the first electrode is a positive bias, it may be a hole or a negative bias). For example, electrons are blocked, and charges flowing into the first electrode are allowed to pass.

The radiation detector according to a third aspect is the configuration of the second aspect , wherein the organic polymer layer has an outer edge portion outside the image information acquisition region, and an average flat portion of the photoconductive layer. It is characterized by being located in a region having a film thickness of 10% or more of the film thickness.

  According to this configuration, the organic polymer layer having charge selectivity does not cover a region having a film thickness of less than 10% of the average thickness of the flat portion of the photoconductive layer, that is, a region having a small film thickness. Creeping discharge that occurs along the molecular layer is difficult to occur.

The radiation detector according to a fourth aspect is the configuration of the third aspect , wherein the organic polymer layer has an outer edge portion outside the first electrode, and the flat portion average film of the photoconductive layer. It is located in a region having a film thickness of 10% or more of the thickness.

  According to this configuration, since the organic polymer layer covers the end portion of the first electrode, discharge breakdown due to electric field concentration on the end portion of the first electrode can be suppressed.

The radiation detector according to a fifth aspect is the configuration according to the fourth aspect , wherein the organic polymer layer has an outer edge portion outside the first electrode, and an end slope of the photoconductive layer. It is characterized by being located in a region where the gradient is 50% or less.

  According to this configuration, the organic polymer layer is formed in a region where the slope of the end slope of the photoconductive layer is 50% or less, whereby the organic polymer layer is formed of a liquid material. However, no dripping occurs.

The radiation detector according to a sixth aspect is characterized in that, in the configuration of any one of the first to fifth aspects , a positive bias is applied to the first electrode.

As in the sixth aspect , a positive bias can be applied to the first electrode. In particular, when amorphous selenium is used for the photoconductive layer, it is preferable to apply a positive bias to the first electrode because amorphous selenium tends to pass holes.

The radiation detector according to a seventh aspect is characterized in that, in the configuration of the sixth aspect , the organic polymer layer contains a hole blocking material.

  According to this configuration, since a positive bias is applied to the first electrode and the organic polymer layer contains the hole blocking material, the organic polymer layer effectively exhibits charge selectivity.

In the radiation detector according to the eighth aspect, in the configuration of the seventh aspect , at least one of the hole blocking materials contained in the organic polymer layer is selected from carbon clusters or derivatives thereof. It is a seed.

The radiation detector according to a ninth aspect is characterized in that, in the configuration of the eighth aspect , the carbon cluster is at least one selected from fullerene C ₆₀ , fullerene C ₇₀ , fullerene oxide or a derivative thereof. And

The manufacturing method of the radiation detector which concerns on a 10th aspect forms the said organic polymer layer into a film using the inkjet method, It is characterized by manufacturing the radiation detector of a 1st aspect .

  According to this configuration, when forming the organic polymer layer, a mask is not required, and the organic polymer layer can be accurately formed without contact with the photoconductive layer.

The manufacturing method of a radiation detector according to an eleventh aspect is characterized in that, in the configuration of the tenth aspect , the discharge liquid used in the ink jet method exhibits dilatancy.

  According to this configuration, since the discharge liquid used in the ink jet method exhibits dilatancy, the discharge liquid has a viscosity when discharging the discharge liquid, while the viscosity of the discharge liquid becomes small at the time of landing. Easy to form a layer.

A radiation detector manufacturing method according to a twelfth aspect is the configuration of the tenth aspect or the eleventh aspect , wherein the discharge liquid used in the inkjet method is selected from carbon clusters or derivatives thereof. It contains a block material and contains at least one of aromatic solvents represented by the general formulas (1) and (2).

(In the general formulas (1) and (2), R1-8 represents hydrogen, halogen, or an alkyl group.)

According to a thirteenth aspect of the method for manufacturing a radiation detector, in any one of the tenth to twelfth aspects, the ejection liquid used in the inkjet method has a contact angle with the photoconductive layer of 45 ° or less. It is characterized by being.

  According to this configuration, since the discharge liquid used in the ink jet method has a contact angle of 45 ° or less with the photoconductive layer, the discharge liquid is easily compatible with the photoconductive layer, and the organic polymer layer is easily formed.

The coating liquid according to the fourteenth aspect is mainly an aromatic solvent containing an organic polymer and fullerenes as essential components, represented by the general formula (1) or (2) and having a boiling point of 150 ° C. or higher. It is a solvent.

(In the general formulas (1) and (2), R1-8 represents hydrogen, halogen, or an alkyl group.)

  According to this configuration, the coating liquid has a boiling point higher than the expected temperature under the environment in which it is normally used, the occurrence of a viscosity change due to the drying of the coating liquid, and the flow path and nozzle for supplying the coating liquid of the coating apparatus It is possible to suppress the occurrence of clogging or the like and the occurrence of sticking to the surface of the application member for applying the application liquid. In addition, the solubility or dispersibility of fullerenes is good even with the main solvent alone, even without adding an additive that may be a concern. Furthermore, the viscosity can be adjusted by changing the molecular weight and concentration of the organic polymer, and the viscosity can be adjusted to suit various coating methods.

The coating liquid according to the fifteenth aspect is applied by being ejected by an ink jet method in the configuration of the fourteenth aspect , and has a viscosity at 25 ° C. in the range of 1-20 mPa · s.

According to this configuration, since the coating is performed by the ink jet method, the organic polymer layer can be accurately formed in a non-contact manner on the coating surface on which the coating is performed without using a mask.
By the way, when the viscosity of the coating liquid is less than 1 mPa · s, liquid dripping may occur from the nozzle. Further, when the viscosity of the coating liquid exceeds 20 mPa · s, non-ejection may occur due to nozzle clogging or the like.
On the other hand, since the coating liquid according to the fifteenth aspect has a viscosity at 25 ° C. in the range of 1-20 mPa · s, the dischargeability is stable.

The coating liquid according to the sixteenth aspect is applied by being ejected by an ink jet method in the configuration of the fourteenth aspect or the fifteenth aspect , and the surface tension at 25 ° C. is in the range of 15-40 mN / m.

According to this configuration, since the coating is performed by the ink jet method, the organic polymer layer can be accurately formed in a non-contact manner on the coating surface on which the coating is performed without using a mask.
By the way, when the surface tension of the coating liquid is less than 15 mN / m, dripping may occur from the nozzle. Moreover, when the surface tension of the coating liquid exceeds 40 mN / m, non-ejection may occur due to nozzle clogging or the like.
On the other hand, since the coating liquid according to the sixteenth aspect has a surface tension at 25 ° C. in the range of 15-40 mN / m, the discharge property is stabilized.

The coating liquid which concerns on a 17th aspect is apply | coated by ejecting by the inkjet method in the structure in any one of the 14th-16th aspect, and shows dilatancy property.

  According to this configuration, since the coating is performed by the ink jet method, the organic polymer layer can be accurately formed in a non-contact manner on the coating surface on which the coating is performed without using a mask. In addition, since the coating liquid exhibits dilatancy, the coating liquid has a viscosity when the coating liquid is ejected by the ink jet method. On the other hand, when landing on the coating surface, the viscosity of the coating liquid is small, so that the coating liquid is easily spread. It is easy to form a simple organic polymer layer.

The coating liquid according to the eighteenth aspect is applied by being ejected by an inkjet method in the configuration of any of the fourteenth to seventeenth aspects, and the contact angle with the application surface on which the application is made is 45 ° or less. It is.

  According to this configuration, since the coating is performed by the ink jet method, the organic polymer layer can be accurately formed in a non-contact manner on the coating surface on which the coating is performed without using a mask. Further, since the coating liquid has a contact angle of 45 ° or less with the coating surface on which the coating is applied, the coating liquid is easy to become familiar with the coating surface when landing on the coating surface, and a uniform organic polymer layer is formed.

A method for producing an organic polymer layer according to a nineteenth aspect includes a step of forming an organic polymer layer by applying the coating liquid according to any one of the fourteenth to eighteenth aspects by ejecting it with an inkjet method, And wet wiping the nozzle surface of the ink jet head used for coating.

  Precipitates generated when the coating liquid adhering to the nozzle surface evaporates can be efficiently removed, and the performance of the inkjet head can be maintained, contributing to the accurate formation of the organic polymer layer.

  The present invention can improve the durability of the radiation detector by defining the formation range of the organic layer.

Below, an example of an embodiment of a radiation detector concerning the present invention is explained based on a drawing.
The radiation detector according to the present embodiment is used in an X-ray imaging apparatus or the like, and includes an electrostatic recording unit including a photoconductive layer that exhibits conductivity when irradiated with radiation. The image information is recorded upon receiving the irradiation of the radiation carrying the image, and the image signal representing the recorded image information is output.

  As the radiation detector, a so-called optical reading type radiation detection substrate 500 that reads using a semiconductor material that generates charges by light irradiation, and charges generated by radiation irradiation are accumulated, and the accumulated charges are stored in a thin film transistor. There is a radiation detector 400 or the like of a method of reading by turning on and off an electrical switch such as a TFT (thin film transistor) one pixel at a time (hereinafter referred to as TFT method).

(Configuration of TFT radiation detector 400)
First, the configuration of the TFT radiation detector 400 will be described. FIG. 1A is a schematic diagram showing the overall configuration of a TFT radiation detector 400. FIG. 2 is a diagram showing a main configuration of the TFT radiation detector 400 and showing each part laminated on the glass substrate.

  As shown in FIGS. 1A and 2, the TFT radiation detector 400 according to the present embodiment is a charge that generates charges when X-rays as an example of radiation carrying image information are incident. As the conversion layer, a photoconductive layer 404 exhibiting electromagnetic wave conductivity is provided. As the photoconductive layer 404, an amorphous material having a high dark resistance, good electromagnetic wave conductivity with respect to X-ray irradiation, and capable of forming a large area film at a low temperature by a vacuum deposition method is preferred.

  For example, an amorphous Se (a-Se) film is used as the amorphous material. A material obtained by doping As, Sb, and Ge into amorphous Se is excellent in thermal stability and is a suitable material for the photoconductive layer 404.

On the photoconductive layer 404, a bias electrode 401 for applying a bias voltage to the photoconductive layer 404 is formed as a first electrode through which radiation carrying image information is transmitted. The bias electrode 401 is made of, for example, gold (Au). The photoconductive layer 404 is irradiated with radiation that has passed through the bias electrode 401.
In the present embodiment, the radiation is irradiated from the bias electrode 401 side. However, a configuration in which irradiation is performed from the glass substrate 408 side described below may be employed. Therefore, the radiation can be irradiated from any direction, whether from the bias electrode 401 side or the glass substrate 408 side. However, in order to prevent attenuation by the glass substrate 408, it is preferable to irradiate from the bias electrode 401.

  Collecting a plurality of charges as a second electrode for collecting the charges generated by the photoconductive layer 404 on the side opposite to the side where the bias electrode 401 is provided with respect to the photoconductive layer 404, that is, below the photoconductive layer 404 An electrode 407a is formed. As shown in FIG. 2, the charge collection electrode 407a is connected to the charge storage capacitor 407c and the switch element 407b, respectively. The charge collection electrode 407a is provided on the glass substrate 408.

  As shown in FIGS. 1A and 2, a hole injection blocking layer 402 having a hole blocking material is provided as an organic polymer layer between the photoconductive layer 404 and the bias electrode 401. ing. Here, the organic polymer layer may also serve as a charge injection blocking layer having charge selectivity. The charge injection blocking layer has charge selectivity, which prevents the charge injection blocking layer from flowing out of the bias electrode 401 with which the charge injection blocking layer is in contact (holes if the bias electrode 401 is positive bias, electrons if it is negative bias). It means that the charge flowing into the bias electrode 401 has a property of passing through.

  That is, as a charge injection blocking layer, a hole injection blocking layer that blocks the injection of holes while being a conductor for electrons, or an electron that blocks the injection of electrons while being a conductor for holes. An injection blocking layer is used. In this embodiment, since the bias electrode 401 is a positive electrode, a hole injection blocking layer 402 is provided as an organic polymer layer.

  As the hole injection blocking layer 402, a film in which a hole blocking material is mixed with an insulating polymer such as polycarbonate, polystyrene, polyimide, polycycloolefin, or the like can be preferably used.

At least one of the hole blocking materials contained in the hole injection blocking layer 402 is preferably at least one selected from carbon clusters or derivatives thereof. Further, the carbon cluster is preferably at least one selected from fullerene C ₆₀ , fullerene C ₇₀ , fullerene oxide or derivatives thereof.

  Further, as shown in FIG. 2, an electron injection blocking layer 406 is provided between the photoconductive layer 404 and the charge collection electrode 407a.

Further, anti-crystallization layers 403 and 405 are provided between the hole injection blocking layer 402 and the photoconductive layer 404 and between the electron injection blocking layer 406 and the photoconductive layer 404, respectively. The crystallization preventing layer 403, 405 GeSe, can be used and _{GeSe 2, Sb 2 Se 3,} a-As 2 Se 3, Se-As, Se-Ge, a Se-Sb-based compounds.

  Note that an active matrix layer 407 is configured by the charge collection electrode 407a, the switch element 407b, and the charge storage capacitor 407c, and an active matrix substrate 450 is configured by the glass substrate 408 and the active matrix layer 407.

  3 is a cross-sectional view showing the structure of one pixel unit of the radiation detector 400, and FIG. 4 is a plan view thereof. The size of one pixel shown in FIGS. 3 and 4 is about 0.1 mm × 0.1 mm to 0.3 mm × 0.3 mm, and this pixel is arranged in a matrix of about 500 × 500 to 3000 × 3000 pixels in the radiation detector as a whole. Has been.

  As shown in FIG. 3, the active matrix substrate 450 includes a glass substrate 408, a gate electrode 411, a charge storage capacitor electrode (hereinafter referred to as Cs electrode) 418, a gate insulating film 413, a drain electrode 412, a channel layer 415, a contact electrode. 416, a source electrode 410, an insulating protective film 417, an interlayer insulating film 420, and a charge collection electrode 407a.

  The gate electrode 411, the gate insulating film 413, the source electrode 410, the drain electrode 412, the channel layer 415, the contact electrode 416, and the like constitute a switch element 407b made of a thin film transistor (TFT), and a Cs electrode 418. Further, a charge storage capacitor 407c is configured by the gate insulating film 413, the drain electrode 412 and the like.

  The glass substrate 408 is a support substrate. As the glass substrate 408, for example, an alkali-free glass substrate (for example, # 1737 manufactured by Corning) can be used. As shown in FIG. 4, the gate electrode 411 and the source electrode 410 are electrode wirings arranged in a lattice pattern, and a switch element 407b made of a thin film transistor is formed at the intersection.

  The source / drain of the switch element 407b is connected to the source electrode 410 and the drain electrode 412 respectively. The source electrode 410 includes a linear portion as a signal line and an extended portion for configuring the switch element 407b, and the drain electrode 412 is provided to connect the switch element 407b and the charge storage capacitor 407c. Yes.

  The source electrode 410 is connected to an extraction electrode 470 that extracts the charges collected by the charge collection electrode 407a to acquire image information. The extraction electrode 470 is provided on the glass substrate 408 and disposed outside the photoconductive layer 404.

  The gate insulating film 413 is made of SiNx, SiOx, or the like. The gate insulating film 413 is provided so as to cover the gate electrode 411 and the Cs electrode 418, and a part located on the gate electrode 411 acts as a gate insulating film in the switch element 407b, and a part located on the Cs electrode 418. Acts as a dielectric layer in the charge storage capacitor 407c. That is, the charge storage capacitor 407c is formed by an overlapping region of the Cs electrode 418 and the drain electrode 412 formed in the same layer as the gate electrode 411. The gate insulating film 413 is not limited to SiNx or SiOx, and an anodic oxide film obtained by anodizing the gate electrode 411 and the Cs electrode 418 can be used in combination.

  A channel layer (i layer) 415 is a channel portion of the switch element 407 b and is a current path connecting the source electrode 410 and the drain electrode 412. A contact electrode (n + layer) 416 makes contact between the source electrode 410 and the drain electrode 412.

  The insulating protective film 417 is formed over almost the entire surface (substantially the entire region) on the source electrode 410 and the drain electrode 412, that is, on the glass substrate 408. Thus, the drain electrode 412 and the source electrode 410 are protected, and electrical insulation and separation are achieved. Further, the insulating protective film 417 has a contact hole 421 at a predetermined position thereof, that is, at a portion located on a portion of the drain electrode 412 facing the Cs electrode 418.

  The charge collection electrode 407a is made of an amorphous transparent conductive oxide film. The charge collection electrode 407a is formed so as to fill the contact hole 421, and is stacked on the source electrode 410 and the drain electrode 412. The charge collection electrode 407a and the photoconductive layer 404 are electrically connected to each other so that charges generated in the photoconductive layer 404 can be collected by the charge collection electrode 407a.

  Next, the charge collection electrode 407a will be described in detail. The charge collection electrode 407a used in this embodiment is composed of an amorphous transparent conductive oxide film. Examples of amorphous transparent conductive oxide film materials include oxides of indium and tin (ITO: Indium-Tin-Oxide), oxides of indium and zinc (IZO: Indium-Zinc-Oxide), indium and germanium. An oxide (IGO: Indium-Germanium-Oxide) or the like having a basic composition can be used.

  As the charge collection electrode 407a, various metal films and conductive oxide films are used, and transparent conductive oxide films such as ITO (Indium-Tin-Oxide) are often used for the following reasons. When the incident X-ray dose is large in the radiation detector 400, unnecessary charges may be trapped in the semiconductor film (or in the vicinity of the interface between the semiconductor film and an adjacent layer).

  Since such residual charges are stored for a long time or move while taking time, the X-ray detection characteristics are deteriorated during the subsequent image detection, and an afterimage (virtual image) appears. Therefore, in Japanese Patent Laid-Open No. 9-9153 (corresponding US Pat. No. 5,563,421), when residual charges are generated in the photoconductive layer 404, the residual charges are reduced by irradiating light from the outside of the photoconductive layer 404. A method of removing by excitation is disclosed. In this case, in order to irradiate light efficiently from the lower side of the photoconductive layer 404 (on the side of the charge collection electrode 407a), the charge collection electrode 407a needs to be transparent to the irradiation light.

  In addition, for the purpose of increasing the area filling factor (fill factor) of the charge collection electrode 407a or for shielding the switch element 407b, it is desirable to form the charge collection electrode 407a so as to cover the switch element 407b. If the collection electrode 407a is opaque, the switch element 407b cannot be observed after the charge collection electrode 407a is formed.

  For example, when the characteristic inspection of the switch element 407b is performed after the charge collection electrode 407a is formed, if the switch element 407b is covered with the opaque charge collection electrode 407a, the cause of the characteristic failure of the switch element 407b is found. Cannot be observed with an optical microscope. Therefore, it is desirable that the charge collection electrode 407a be transparent so that the switch element 407b can be easily observed even after the charge collection electrode 407a is formed.

  The interlayer insulating film 420 is made of a photosensitive acrylic resin, and serves to electrically isolate the switch element 407b. A contact hole 421 passes through the interlayer insulating film 420, and the charge collection electrode 407 a is connected to the drain electrode 412. The contact hole 421 is formed in a reverse taper shape as shown in FIG. A high voltage power supply (not shown) is connected between the bias electrode 401 and the Cs electrode 418.

  Next, a configuration for covering the photoconductive layer 404 will be described. As shown in FIG. 1A, a cover glass 440 as an example of a cover member that covers the bias electrode 401 is provided above the bias electrode 401.

The glass substrate 408 is provided with a protective member 442 to which the cover glass 440 is bonded.
The protective member 442 surrounds the periphery of the photoconductive layer 404, and is formed in a box shape with the upper and lower portions opened as a whole.

  Further, the protective member 442 has a side wall 442a erected on the outer peripheral portion of the glass substrate 408, and a flange portion 442b protruding from the upper part of the side wall 442a to the upper side of the central portion of the glass substrate 408. It is formed in an L shape.

  The cover glass 440 has an upper surface of the outer peripheral portion bonded to the lower surface (inner wall) of the flange portion 442b and is supported by the protective member 442.

  The joint between the protective member 442 and the cover glass 440 is disposed outside the photoconductive layer 404. That is, the protective member 442 and the cover glass 440 are bonded to each other in a region where the photoconductive layer 404 on the glass substrate 408 is not present, but not above the photoconductive layer 404.

  Note that an insulating member having an insulating property is used for the protective member 442. As the insulating member, for example, polycarbonate, polyethylene terephthalate (PET), polymethyl methacrylate (acrylic), or polyvinyl chloride is used.

  Further, the protective member 442 has a lower opening closed by a glass substrate 408 and an upper opening closed by a cover glass 440, so that a closed space of a predetermined size is formed in the protective member 442. The photoconductive layer 404 is accommodated in the closed space, and the photoconductive layer 404 is covered with the cover glass 440, the glass substrate 408, and the protective member 442.

  In addition, a space surrounded by the cover glass 440, the protection member 442, and the glass substrate 408 is filled with a curable resin 444 as a filling member. As the curable resin 444, for example, a room temperature curable resin such as epoxy or silicon is used.

(Range of formation of hole injection blocking layer 402)
Here, the formation range of the hole injection blocking layer 402 will be described.

  The hole injection blocking layer 402 as an organic polymer layer has an outer edge, that is, a peripheral edge serving as a boundary with another layer is positioned at a predetermined position, so that the hole injection blocking layer 402 is formed in a predetermined range. The configuration covers the predetermined range.

  In the present embodiment, the outer edge portion of the hole injection blocking layer 402 includes the region end G1 of the image information acquisition region G from which the image information is acquired and the extraction electrode 470, among the regions irradiated with the radiation carrying the image information. It is comprised so that it may be located between. A range indicated by an arrow A in FIG. 1A is a range between the region end G1 of the image information acquisition region G and the extraction electrode 470.

  Preferably, the outer edge portion of the hole injection blocking layer 402 according to the present embodiment is outside the image information acquisition region G and has a film thickness of 10% or more of the average thickness of the flat portion of the photoconductive layer 404. It is comprised so that it may be located in the area | region which has. The flat part average film thickness of the photoconductive layer 404 is obtained by measuring the film thicknesses of nine arbitrary points in the image information acquisition region G of the photoconductive layer 404 and averaging the film thicknesses of the nine points. The film thickness was measured by observing the cross section with a microscope at a magnification of 100 times.

  Note that the range indicated by the arrow B in FIG. 1A is the range outside the image information acquisition region G and within the region having a film thickness of 10% or more of the average thickness of the flat portion of the photoconductive layer 404. is there.

  More preferably, the outer edge portion of the hole injection blocking layer 402 according to this embodiment is outside the bias electrode 401 and is in a region having a thickness of 10% or more of the average thickness of the flat portion of the photoconductive layer 404. It is comprised so that it may be located in.

  Note that a range indicated by an arrow C in FIG. 1A is a range outside the bias electrode 401 and in a region having a thickness of 10% or more of the average thickness of the flat portion of the photoconductive layer 404.

  More preferably, the outer edge portion of the hole injection blocking layer 402 is located outside the bias electrode 401 and located in a region where the slope of the end slope of the photoconductive layer 404 is 50% or less.

  The outer edge portion of the hole injection blocking layer 402 is an end slope where the gradient gradually increases from the flat portion to the outer edge of the photoconductive layer 404, and the gradient is within 50% or less, that is, the gradient is greater than 50%. Is located in a gentle range. As shown in FIG. 1B, the gradient is 50% in a right triangle formed of a side along the film thickness direction of the photoconductive layer 404, a side perpendicular to the side, and a hypotenuse. This is a slope formed by the hypotenuse when the length of the side along the film thickness direction of the conductive layer 404 is 1 and the length of the side perpendicular to the side is 2. The gradient was measured by microscopic observation of the cross section at a magnification of 100 times.

  Note that the range indicated by the arrow D in FIG. 1A is the range outside the bias electrode 401 and in the region where the slope of the end slope of the photoconductive layer 404 is 50% or less.

  The photoconductive layer 404 is formed in a wider area than the bias electrode 401. The charge collection electrode 407a is formed in a region wider than the image information acquisition region G.

  Note that the outer edge portion of the hole injection blocking layer 402 according to this embodiment may be configured to be located outside the image information acquisition region G and within the region of the photoconductive layer 404.

(Operation principle of TFT radiation detector)
Next, the operation principle of the above-described TFT radiation detector 400 will be described. When the photoconductive layer 404 is irradiated with X-rays, charges (electron-hole pairs) are generated in the photoconductive layer 404. In a state where a voltage is applied between the bias electrode 401 and the Cs electrode 418, that is, in a state where a voltage is applied to the photoconductive layer 404 via the bias electrode 401 and the Cs electrode 418, charge accumulation with the photoconductive layer 404 is performed. Since the capacitor 407c is electrically connected in series, the electrons generated in the photoconductive layer 404 move to the + electrode side, and the holes move to the-electrode side. As a result, the charge storage capacitor Charge is accumulated in 407c.

  The charge stored in the charge storage capacitor 407c can be extracted to the outside from the source electrode 410 through the extraction electrode 470 by turning on the switch element 407b by an input signal to the gate electrode 411. Since the electrode wiring composed of the gate electrode 411 and the source electrode 410, the switch element 407b, and the charge storage capacitor 407c are all provided in a matrix, signals input to the gate electrode 411 are sequentially scanned to obtain the source electrode 410. By detecting the signal from each source electrode 410, X-ray image information can be obtained two-dimensionally.

Example 1
In Example 1, an electron injection blocking layer 406 made of antimony sulfide having a thickness of 2 μm is formed on the active matrix substrate 450. Next, a Se raw material containing 3% of As was formed into a film by vapor deposition to form a crystallization prevention layer 405 having a thickness of 0.15 μm. Subsequently, a Se raw material containing 10 ppm of Na was deposited by vapor deposition to form a photoconductive layer 404 made of amorphous Se having a thickness of 1000 μm.

  Next, a discharge liquid containing at least one kind of hole blocking material selected from carbon clusters or derivatives thereof and containing at least one kind of aromatic solvent represented by the general formulas (1) and (2) is used. Thus, a hole injection blocking layer 402 as an organic polymer layer was formed.

(In the general formulas (1) and (2), R1-8 represents hydrogen, halogen, or an alkyl group.)

In this embodiment, as the carbon cluster, using fullerene C _60. For fullerene C ₆₀ , nanom purple (C ₆₀ ) manufactured by Frontier Carbon Co., Ltd. was used.

Moreover, in this example, 1.05 wt% polycarbonate resin (PCz) (Iupilon PCz-400 manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 30 wt% with respect to PCz were added to o-dichlorobenzene as the aromatic solvent. by dissolving the fullerene C _60, to produce a discharge liquid.

The discharged liquid shows dilatancy. Dilatancy refers to the property of a liquid whose viscosity increases with increasing shear rate. The relationship between the shear rate and the shear viscosity of the discharged liquid was measured by a rheometer (Anton Paar: Physica MCR301). The measurement was performed twice in the range of the shear rate of 10-1000 [s ⁻¹ ], and the average value is shown in FIG. Since the shear viscosity increases with increasing shear rate, it can be said to be dilatancy.

The exponential approximation in the graph of FIG. 5 is y = 2.2331e ^1E-05x . The shear rate applied to the ejected liquid during ejection from the inkjet head is generally said to be about 10 ⁵ [s ⁻¹ ], and the shear viscosity at that time is expected to be 6.07 [mPa · s]. On the other hand, since the shear rate after landing is considered to be 0 [s ^-1 ], the shear viscosity at that time is expected to be 2.23 [mPa · s]. Since the viscosity decreases after landing, the liquid easily spreads and is clearly suitable for forming a uniform film.

  Further, the discharge liquid has a contact angle with the photoconductive layer 404 of 45 ° or less. In this example, a discharge liquid having a contact angle with the photoconductive layer 404 of 5 ° was used.

  The discharged liquid was filled in an inkjet head SE-128 manufactured by FUJIFILM Dimatix, and discharged over a range wider than the image information acquisition region G and not on the extraction electrode 470. The solvent was evaporated with a vacuum dryer to obtain a hole injection blocking layer 402 having a thickness of 0.2 μm. Finally, Au was deposited on the inner side of the hole injection blocking layer 402 end to form a bias electrode 401 having a thickness of 0.1 μm. The remaining amount of the solvent in the organic polymer layer was about 1 ppm (the same applies hereinafter).

  In the configuration of the present embodiment, the outer edge portion of the hole injection blocking layer 402 is located on the 1 mm image information acquisition region G side from the extraction electrode 470, and the region end G1 of the image information acquisition region G from which image information is acquired. And the extraction electrode 470.

Thereby, the hole injection blocking layer 402 covers the image information acquisition region G of the photoconductive layer 404, so that deterioration such as crystallization in the image information acquisition region G of the photoconductive layer 404 can be suppressed, and the radiation detector 400 As a result, durability is improved. In addition, since the hole injection blocking layer 402 does not cover the extraction electrode 470, poor conduction of the extraction electrode 470 can be prevented. The configuration of Example 1 corresponds to the configuration of the first aspect .

(Example 2)
In Example 2, the outer edge portion of the hole injection blocking layer 402 is located 1 mm inward from the end of the bias electrode 401, is outside the image information acquisition region G, and is the average thickness of the flat portion of the photoconductive layer 404. It is comprised so that it may be located in the area | region which has a film thickness of 10% or more.

According to the configuration of this example, the hole injection blocking layer 402 having charge selectivity has a region having a film thickness of less than 10% of the average thickness of the flat portion of the photoconductive layer 404, that is, a region having a small film thickness. Since it is not covered, creeping discharge that occurs along the hole injection blocking layer 402 hardly occurs. The configuration of Example 2 corresponds to the configuration of the third aspect .

(Example 3)
In Example 3, the outer edge portion of the hole injection blocking layer 402 is located at a location that is 50% of the average thickness of the flat portion of the photoconductive layer 404, outside the bias electrode 401, and on the photoconductive layer 404. It is comprised so that it may be located in the area | region which has a film thickness of 10% or more of a flat part average film thickness.

According to the configuration of the present embodiment, since the hole injection blocking layer 402 covers the end portion of the bias electrode 401, discharge breakdown due to electric field concentration on the end portion of the bias electrode 401 can be suppressed. The configuration of Example 3 corresponds to the configuration of the fourth aspect .

Example 4
In Example 4, the outer edge of the hole injection blocking layer 402 is located 2 mm outside the end of the bias electrode 401, outside the bias electrode 401, and the slope of the end slope of the photoconductive layer 404 is 50%. It is configured to be located in the following area.

According to the configuration of this example, the hole injection blocking layer 402 is formed in a region where the slope of the end slope of the photoconductive layer 404 is 50% or less, so that the hole injection blocking layer 402 is in a liquid state. Even when it is made of a material, no dripping occurs. When liquid pool by dripping occurs, although crystallization of the C ₆₀ is creeping discharge is likely to occur to occur, in the present embodiment, since not generated dripping, it is possible to suppress creeping discharge.

Note that the hole injection blocking layer 402 may have a two-layer structure, and antimony sulfide having a thickness of 0.6 μm may be stacked in an organic polymer layer containing fullerene. With this configuration, the hole blocking property can be improved. The configuration of the fourth embodiment corresponds to the configuration of the fifth aspect .

(Comparative Example 1)
In Comparative Example 1, the hole injection blocking layer 402 is formed so that the outer edge portion of the hole injection blocking layer 402 is located inside the region end G1 of the image information acquisition region G. Thereby, the hole injection blocking layer 402 is formed in a narrower range than the image information acquisition region G.

  In the configuration of Comparative Example 1, crystallization occurred in the photoconductive layer 404 formed of amorphous selenium (a-Se) in the portion where the hole injection blocking layer 402 was not present, and image acquisition was impossible.

(Comparative Example 2)
In Comparative Example 2, the hole injection blocking layer 402 was formed so that the hole injection blocking layer 402 was placed on the extraction electrode 470.

  In the configuration of Comparative Example 2, contact failure occurred when the extraction electrode 470 and the active matrix substrate 450 were connected.

(Configuration of optical reading radiation detector)
The present invention can also be applied to an optical reading type radiation detector, and is applied according to the configuration of the hole injection blocking layer 402 in the radiation detector 400 described above. Here, a radiation detection substrate 500 as an optical reading type radiation detector will be described.

  6A and 6B are schematic views of the radiation detection substrate 500. FIG. As shown in FIGS. 6A and 6B, the radiation detection substrate 500 is connected with a TCP 510, a reading device 512 connected thereto, and a high voltage line 514 for applying a high voltage.

  A TCP (Tape Carrier Package) 510 is a flexible wiring board on which a signal detection IC (charge amplifier IC) 511 is mounted. The TCP 510 is connected by thermocompression bonding using an ACF (Anisotropic Conductive Film).

  An extended electrode portion 519 extending from the upper electrode 518 above the detection area 516 is formed, and a high voltage line 514 is connected to the extended electrode portion 519. The detection area 516 for detecting radiation includes a lower electrode 520 for reading signals and applying a high voltage, a radiation detection layer 522 for converting radiation into charges, and an upper electrode 518 for applying a high voltage.

  The lower electrode 520 is provided on the glass substrate 536, and the radiation detection lower substrate 524 is configured by the glass substrate 536 provided with the lower electrode 520.

  The production of the radiation detection substrate 500 is roughly divided into the production of a radiation detection lower substrate 524 including the lower electrode 520, the formation of the radiation detection layer 522 and the upper electrode 518, and the connection of the high voltage line 514.

  Hereinafter, the structure of the radiation detection lower substrate 524 will be described. FIG. 7 shows a schematic structure of the radiation detection lower substrate 524. In FIG. 7, TCP 510 is simplified to one channel on the left and three channels on each side for a total of 6 channels. As shown in FIG. 7, the radiation detection lower substrate 524 includes a radiation detection unit 526, a pitch conversion unit 528, and a TCP connection unit 530 as an extraction electrode.

  In the radiation detection unit 526, lower electrodes 520 for extracting signals are arranged in a stripe shape (line shape). In addition, a color filter layer 534 that partially transmits only light having an arbitrary wavelength is formed under the transparent organic insulating layer 532.

  The layer above the color filter layer 534 is referred to as a common B line 520B, and the signal S line 520S in a portion without the color filter layer 534. The B line 520B is shared outside the radiation detection unit and has a comb electrode structure. The S line 520S is used as a signal line. The width of the B line 520B is, for example, 20 μm, the width of the S line 520S is, for example, 10 μm, and the interval between the B line 520B and the S line 520S is, for example, 10 μm.

  The width of the color filter layer 534 is, for example, 30 μm. The lower electrode 520 is transparent to irradiate light from the back surface, and needs flatness to avoid breakdown due to electric field concentration when a high voltage is applied. For example, IZO or ITO is used. When IZO is used, the thickness is 0.2 μm and the flatness is about Ra = 1 nm.

  The color filter layer 534 is a photosensitive resist in which a pigment is dispersed, for example, a red resist used for an LCD color filter. In order to eliminate the level difference of the color filter layer 534, a photosensitive organic transparent insulating layer 532 such as PMMA is used.

  Further, the glass substrate 536 serving as a support member is preferably transparent and rigid, and more preferably soda lime glass. As an example of the thickness of each layer, the lower electrode 520 is 0.2 μm, the color filter layer 534 is 1.2 μm, the organic transparent insulating layer 532 is 1.8 μm, and the glass substrate 536 is 1.8 mm. The color filter layer 534 and the organic insulating layer 532 are provided only in the radiation detection unit 526, and the boundary is in the radiation detection unit 526 and the pitch conversion unit 528. For this reason, the IZO wiring is formed on the glass substrate 536 in the TCP connection portion 530 via the boundary step portion of the organic insulating layer 532.

  In the radiation detection unit 526, wiring is taken out to the left and right TCPs 510 in units of a certain number. In FIG. 7, it is a unit of 3 lines. An example of the number of lines is 256 lines. The line width in the radiation detection unit 526 is different from the line width in the TCP connection unit 530 and is adjusted, and the line width is adjusted in the pitch conversion unit 528 in order to route the wiring to a predetermined TCP connection position. The B line 520B is made common and similarly drawn out to the TCP connection unit 530.

  In the TCP connection unit 530, the signal S line 520S and the common B line 520B shared by the outside of the radiation detection unit are arranged. The common B line 520B is disposed outside the signal S line 520S. As an example of the number, the signal line 256 and the common line are connected to the TCP using five lines above and below. The electrode line / space is 40/40 μm.

  In addition, an alignment mark for TCP is necessary to connect TCP with this TCP connection unit 530. Although it is desirable to form with a transparent electrode, it is difficult to recognize because it is transparent, and an alignment mark is formed using, for example, a color filter layer 534 that is a constituent member of this substrate as an opaque material.

  Next, the radiation detection layer 522 will be described. FIG. 8 is a schematic view schematically showing the configuration of the radiation detection substrate 500. As shown in FIG. 8, the radiation detection layer includes a recording photoconductive layer 542, a charge storage layer 544, a reading photoconductive layer 546, an electrode interface layer 548, an undercoat layer 550, and an overcoat layer 552. ing.

<Photoconductive layer for recording>
The recording photoconductive layer 542 is a photoconductive material that absorbs electromagnetic waves and generates charges, and is an amorphous selenium compound, 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, and the like. Of these, an amorphous selenium compound is particularly preferable.

  In the case of an amorphous selenium compound, the layer is doped with a small amount of alkali metal such as Li, Na, K, Cs, Rb between 0.001 ppm and 1 ppm, LiF, NaF, KF, CsF, RbF, etc. A small amount of 10 to 10,000 ppm of fluoride, P, As, Sb, Ge added between 50 ppm and 0.5%, As doped from 10 ppm to 0.5%, Cl, Br , I doped in a slight amount between 1 ppm and 100 ppm can be used.

  In particular, amorphous selenium containing about 10 ppm to 200 ppm of As, amorphous selenium containing about 0.2% to 1% of As and further containing 5 ppm to 100 ppm of Cl, and alkali metals of about 0.001 ppm to 1 ppm were contained. Amorphous selenium is preferably used.

Also, 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 Those containing fine particles of a photoconductive substance such as BiI ₃ or GaAs can also be used.

  The thickness of the recording photoconductive layer 542 is preferably 100 μm or more and 2000 μm or less in the case of amorphous selenium. In particular, it is particularly preferably in the range of 150 μm or more and 250 μm or less for mammography, and in the range of 500 μm or more and 1200 μm or less for general photographing applications.

<Charge storage layer>
The charge storage layer 544 may be any film that is insulative with respect to the polar charge to be stored, such as an acrylic organic resin, polyimide, BCB, PVA, acrylic, polyethylene, polycarbonate, polyetherimide, or a polymer such as As ₂ S. ₃ , sulfides such as Sb ₂ S ₃ and ZnS, oxides and fluorides. Furthermore, it is more preferable to be insulative with respect to the charge of the polarity to be accumulated, and to be conductive with respect to the charge with the opposite polarity. Substances with differences are preferred.

Preferable compounds include As ₂ Se ₃ , As ₂ Se ₃ doped with Cl, Br, I from 500 ppm to 20000 ppm, and As ₂ Se ₃ Se ₂ substituted with Te to about 50% (Se _x Te _1-x ) ₃ (0.5 <x <1), As ₂ Se ₃ with Se replaced to about 50%, As _x Se _y with As concentration changed by ± 15% from As ₂ Se ₃ ( x + y = 100, 34 ≦ x ≦ 46), an amorphous Se—Te system containing 5-30 wt% Te.

  In the case of using such a substance containing a chalcogenide element, the thickness of the charge storage layer 544 is preferably 0.4 μm to 3.0 μm, more preferably 0.5 μm to 2 μm. Such a charge storage layer 544 may be formed by a single film formation or may be laminated in a plurality of times.

  As a preferable charge storage layer 544 using an organic film, a compound obtained by doping a charge transport agent with a polymer such as an acrylic organic resin, polyimide, BCB, PVA, acrylic, polyethylene, polycarbonate, or polyetherimide is preferably used. . Preferred charge transport agents include tris (8-quinolinolato) aluminum (Alq3), N, N-diphenyl-N, N-di (m-tolyl) benzidine (TPD), polyparaphenylene vinylene (PPV), polyalkylthiophene. , Polyvinylcarbazole (PVK), triphenylene (TNF), metal phthalocyanine, 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (DCM), liquid crystal molecules, hexapentyloxytriphenylene And a molecule selected from the group consisting of a discotic liquid crystal molecule having a central core containing a π-conjugated condensed ring or a transition metal, a carbon nanotube, and fullerene. The doping amount is set between 0.1 and 50 wt.%.

<Reading photoconductive layer>
The photoconductive layer 546 for reading is a photoconductive material that absorbs electromagnetic waves, particularly visible light, and generates electric charge. The energy gap of amorphous selenium compound, amorphous Si: H, crystalline Si, GaAs, etc. is in the range of 0.7-2.5 eV. The semiconductor substance contained in the can be used. In particular, amorphous selenium is preferable.

In the case of an amorphous selenium compound, the layer is doped with a small amount of alkali metal such as Li, Na, K, Cs, Rb between 0.001 ppm and 1 ppm, LiF, NaF, KF, CsF, RbF, etc. A small amount of fluoride of 10ppm to 10000ppm, P, As, Sb, Ge added between 50ppm to 0.5%, As doped from 10ppm to 0.5%, Cl, Br , I doped in a slight amount between 1 ppm and 100 ppm can be used.
In particular, amorphous selenium containing about 10 ppm to 200 ppm of As, amorphous selenium containing about 0.2% to 1% of As and further containing 5 ppm to 100 ppm of Cl, and alkali metals of about 0.001 ppm to 1 ppm were contained. Amorphous selenium is preferably used.

  The thickness of the reading photoconductive layer 546 is not limited as long as it can sufficiently absorb the reading light and the electric field generated by the charges accumulated in the charge storage layer 544 can drift the photoexcited charge, and is preferably about 1 μm to 30 μm.

<Electrode interface layer>
The electrode interface layer 548 is laid between the recording photoconductive layer 542 and the upper electrode 518 or between the reading photoconductive layer 546 and the lower electrode 520. For the purpose of preventing crystallization, amorphous selenium with As added in the range of 1% -20%, S, Te, P, Sb, Ge added in the range of 1% to 10%, the above What added the combination of an element and another element is preferable.

Alternatively, As ₂ S ₃ and As ₂ Se ₃ having a higher crystallization temperature can also be preferably used. Furthermore, in addition to the above-mentioned additive elements for the purpose of preventing charge injection from the electrode layer, in particular, alkali metals such as Li, Na, K, Rb, Cs, LiF, NaF, KF to prevent hole injection It is also preferable to dope a molecule such as RbF, CsF, LiCl, NaCl, KCl, RbF, CsF, CsCl, CsBr in the range of 10 ppm to 5000 ppm. Conversely, in order to prevent electron injection, it is also preferable to dope a halogen element such as Cl, I, or Br, or a molecule such as In ₂ O _{3 in} the range of 10 ppm to 5000 ppm. The thickness of the interface layer is preferably set between 0.05 μm and 1 μm so as to sufficiently fulfill the above purpose.

The electrode interface layer 548, the reading photoconductive layer 546, the charge storage layer 544, and the recording photoconductive layer 542 have a substrate temperature of 25 ° C. or higher in a vacuum chamber having a degree of vacuum of 10 ⁻³ to 10 ⁻⁷ Torr. The boat or crucible containing each of the above alloys is kept at a temperature of 70 ° C. or lower and heated by resistance heating or electron beam to evaporate or sublimate the alloy or compound, and are laminated on the substrate.

When the evaporation temperatures of the alloy and the compound are greatly different, it is also preferable to control the addition concentration and the dope concentration by simultaneously heating and individually controlling a plurality of boats corresponding to a plurality of evaporation sources. For example, As ₂ Se ₃ / Amorphous selenium / LiF are put in a boat, As ₂ Se ₃ boat is 340 ° C, Amorphous selenium (a-Se) boat is 240 ° C, LiF boat is 800 ° C, and each boat By opening and closing the shutter, a layer of As10% doped amorphous selenium doped with 5000 ppm LiF can be formed.

<Underlayer>
An undercoat layer 550 can be provided between the reading photoconductive layer 546 and the lower electrode (charge collecting electrode) 520. When there is an electrode interface layer (crystallization prevention layer (A layer)) 548, it is preferably provided between the electrode interface layer 548 and the lower electrode 520. The undercoat layer 550 preferably has rectification characteristics from the viewpoint of reducing dark current and leakage current. It is preferable to have an electron blocking property when a positive bias is applied to the upper electrode 518 and a hole blocking property when a negative bias is applied.

The resistivity of the undercoat layer is preferably 10 ⁸ Ωcm or more, and the film thickness is preferably 0.01 μm to 10 μm. As a layer having an electron blocking property, that is, an electron injection blocking layer, a layer made of a composition such as Sb ₂ S ₃ , SbTe, ZnTe, CdTe, SbS, AsSe, As ₂ S ₃ or an organic polymer layer is preferable. As the organic polymer layer, a film in which NPD or TPD is mixed with a hole transporting polymer such as PVK or an insulating polymer such as polycarbonate, polystyrene, polyimide, or polycycloolefin can be preferably used.

As a layer having a hole blocking property, that is, a hole injection blocking layer, a film of CdS, CeO ₂ , or the like, or an organic polymer layer is preferable. As the organic polymer layer, a film obtained by mixing a carbon cluster such as C ₆₀ (fullerene) or C ₇₀ with an insulating polymer such as polycarbonate, polystyrene, polyimide, or polycycloolefin can be preferably used.

  On the other hand, a thin insulating polymer layer can also be preferably used. For example, parylene, polycarbonate, PVA, PVP, PVB, a polyester resin, an acrylic resin such as polymethyl methacrylate is preferable. The film thickness at this time is preferably 2 μm or less, and more preferably 0.5 μm or less.

<Upper layer>
An overcoat layer 552 can be provided between the recording photoconductive layer 542 and the upper electrode (voltage application electrode) 518. When there is an electrode interface layer (crystallization prevention layer (C layer)) 548, it is preferably provided between the electrode interface layer 548 and the upper electrode 518. The overcoat layer 552 preferably has rectification characteristics from the viewpoint of reducing dark current and leakage current.

It is preferable to have a hole blocking property when a positive bias is applied to the upper electrode 518, and an electron blocking property when a negative bias is applied. The resistivity of the overcoat layer is preferably 10 ⁸ Ωcm or more, and the film thickness is preferably 0.01 μm to 10 μm.

  As the layer having electron blocking properties, that is, the electron injection blocking layer, an organic polymer layer is preferable. As the organic polymer layer, a film in which NPD or TPD is mixed with a hole transporting polymer such as PVK or an insulating polymer such as polycarbonate, polystyrene, polyimide, or polycycloolefin can be preferably used.

  As the layer having a hole blocking property, that is, a hole injection blocking layer, an organic polymer layer is preferable. As the organic polymer layer, a film obtained by mixing a hole blocking material with an insulating polymer such as polycarbonate, polystyrene, polyimide, polycycloolefin, or the like can be preferably used.

At least one of the hole blocking materials contained in the hole injection blocking layer 402 is preferably at least one selected from carbon clusters or derivatives thereof. Further, the carbon cluster is preferably at least one selected from fullerene C ₆₀ , fullerene C ₇₀ , fullerene oxide or derivatives thereof.

  On the other hand, a thin insulating polymer layer can also be preferably used. For example, parylene, polycarbonate, PVA, PVP, PVB, a polyester resin, an acrylic resin such as polymethyl methacrylate is preferable. The film thickness at this time is preferably 2 μm or less, and more preferably 0.5 μm or less.

  Next, the upper electrode 518 and the surface protective layer 554 formed on the surface of the upper electrode 518 will be described.

<Upper electrode>
As the upper electrode 518 formed on the upper surface of the recording photoconductive layer 542, a metal thin film is preferably used. Materials include Au, Ni, Cr, Au, Pt, Ti, Al, Cu, Pd, Ag, Mg, MgAg3-20% alloy, Mg-Ag intermetallic compound, MgCu3-20% alloy, Mg-Cu metal What is necessary is just to make it form from metals, such as an intermetallic compound.

  In particular, Au, Pt, and Mg—Ag intermetallic compounds are preferably used. For example, when Au is used, the thickness is preferably 15 nm to 200 nm, more preferably 30 nm to 100 nm. For example, when an MgAg3-20% alloy is used, it is more preferable to use a thickness of 100 nm to 400 nm.

Although the preparation method is arbitrary, it is preferably formed by vapor deposition by a resistance heating method.
For example, after a metal lump is melted in a boat by a resistance heating method, the shutter is opened, vapor deposition is performed for 15 seconds, and cooling is performed once. It is formed by repeating a plurality of times until the resistance value becomes sufficiently low.

<Surface protective layer>
In order to form a latent image on the radiation detection device by irradiation, a high voltage of several kV is applied to the upper electrode 518. If the upper electrode 518 is open to the atmosphere, creeping discharge is generated, and there is a risk of electric shock of the subject. In order to prevent creeping discharge in the upper electrode 518, a surface protective layer 554 is formed on the upper surface of the electrode and subjected to insulation treatment.

  Insulation treatment requires a structure in which the electrode surface does not come into contact with the atmosphere at all, and a structure in which the electrode surface is tightly covered with an insulator. In addition, this insulator needs to have a dielectric breakdown strength exceeding the applied potential. Furthermore, it is necessary for the function of the radiation detection device to be a member that does not interfere with radiation transmission. As a material and manufacturing method of these required covering properties, high dielectric breakdown strength and high radiation transmittance, vapor deposition of insulating polymer or solvent coating is preferable.

  Specific examples include a room temperature curing type epoxy resin, a polycarbonate resin, a polyvinyl butyral resin, a polyvinyl alcohol resin, an acrylic resin, and a method of forming a polyparaxylylene derivative by a CVD method. Among these, a room temperature curing type epoxy resin and polyparaxylylene are preferably formed by a CVD method, and a method of forming a polyparaxylylene derivative by a CVD method is particularly preferable. A preferable film thickness is 10 μm or more and 1000 μm or less, and more preferably 20 μm or more and 100 μm or less.

  A polyparaxylylene film can be formed at room temperature, so that an insulating film with extremely high step coverage can be obtained without applying thermal stress to the adherend, but it is chemically very stable. In general, the adhesion is often not preferred. In order to increase the adhesion with the adherend, as a treatment to the adherend before the formation of polyparaxylylene, physical, such as a coupling agent, corona discharge, plasma treatment, ozone cleaning, acid treatment, surface treatment, Chemical treatment is generally known and can be used. In particular, a polyparaxylylene film is formed after applying a silane coupling agent or a solution obtained by diluting a silane coupling agent with an alcohol or the like if necessary to at least improve the adhesion to the adherend. A method of improving the adhesion with the adherend is preferable.

  Furthermore, it is preferable to perform a moisture-proof treatment to prevent the radiation detection device from aging. Specifically, the structure is covered with a moisture-proof member. As the moisture-proof member, a resin alone such as the insulating polymer is insufficient in function, and a configuration having at least an inorganic material layer such as glass or an aluminum laminate film is effective. However, since glass attenuates radiation transmission, the moisture-proof member is preferably a thin aluminum laminate film. For example, as an aluminum laminate film generally used as a moisture-proof packaging material, there is a laminate of PET 12 μm / rolled aluminum 9 μm / nylon 15 μm.

  The thickness of aluminum is preferably 5 μm or more and 30 μm or less, and the front and rear PET thicknesses and nylon thicknesses are each preferably 10 μm or more and 100 μm or less. The X-ray attenuation of this film is about 1%, which is optimal as a member that achieves both a moisture-proof effect and X-ray transmission.

  For example, as shown in FIG. 9, the entire surface of the radiation detection device subjected to insulation treatment with polyparaxylylene 554A is covered with a moisture-proof film 554B, and the periphery of the moisture-proof film 554B is bonded and fixed to the substrate with an adhesive outside the radiation detection device region. To do. Thus, the radiation detection device is sealed with the substrate and the moisture-proof film 554B.

  At the time of this adhesion and fixation, polyparaxylylene 554A is chemically very stable, and therefore generally has poor adhesion to other members by an adhesive, but light irradiation treatment with ultraviolet light prior to adhesion is performed. The adhesion can be improved by applying. The necessary irradiation time is appropriately adjusted to the optimum time depending on the wavelength and wattage of the ultraviolet light source to be used, but it is preferably 1 to 50 W with a low-pressure mercury lamp, and the light irradiation is preferably performed for 1 to 30 minutes.

  Note that the radiation detection device according to the present embodiment uses amorphous selenium, and amorphous selenium may crystallize at a high temperature of 40 ° C. or higher, so that a latent image forming function may not be obtained. Processing is not suitable. Therefore, a room temperature curable adhesive is desirable, and a two-component mixed room temperature curable epoxy adhesive having a high adhesive strength is optimal. This epoxy adhesive is applied to the outer periphery of the radiation detection device and covered with a moisture-proof film 554B. The adhesive portion is pressed and fixed uniformly from the upper surface of the moisture-proof film 554B, and is left in this state for 12 hours or more in a room temperature environment to be cured. After the adhesive is cured, the pressure is released to complete the sealing structure.

  It supplements about a sealing structure member. When a radiation detection device is used for mammography, imaging detection with a low dose is desired in order to suppress exposure in X-ray imaging. In order to detect a change in shadow caused by low-dose irradiation, it is desirable that members other than the subject (mammo) in the path from the radiation source to the device have a high X-ray transmittance, thereby obtaining a clear image.

  Although an example of a preferable protective layer / sealing structure is shown in FIG. 9, it is not limited to this. It is preferable to maintain the humidity environment of the device at 30% or less, more preferably 10% or less by forming the protective film.

<Charge extraction amplifier>
In the present embodiment, the charge is A / D converted after being amplified through an amplifier. FIG. 10 is a block diagram showing the configuration of the charge extraction amplifier and the connection mode between the charge extraction amplifier and the image processing apparatus 150 arranged outside the radiation detection substrate 500.

  The charge amplifier IC 511 as a charge extraction amplifier is a multiplexer that multiplexes a number of charge amplifiers 33a and sample hold (S / H) 33b connected to each element 15a of the radiation detection substrate 500, and a signal from each sample hold 33b. 33c.

  The current flowing out from the lower electrode is converted into a voltage by each charge amplifier 33a, the voltage is sampled and held at a predetermined timing by the sample hold 33b, and the voltage corresponding to each sampled and held element 15a is switched in the arrangement order of the elements 15a. Are sequentially output from the multiplexer 33c (corresponding to a part of main scanning).

  The signal sequentially output from the multiplexer 33c is input to the multiplexer 31c provided on the printed circuit board 31, and further, the voltage corresponding to each element 15a is sequentially output from the multiplexer 31c so as to be switched in the arrangement order of the elements 15a, thereby completing the main scanning. To do.

  The signals sequentially output from the multiplexer 31c are converted into digital signals by the A / D converter 31a, and the digital signals are stored in the memory 31b. The image signal once stored in the memory 31b is sent to an external image processing device 150 via a signal cable, and appropriate image processing is performed in the image processing device 150, and the image signal is uploaded to the network 151 together with the photographing information, and the server Or it is sent to a printer.

<Image acquisition sequence>
The image forming sequence of this image recording / reading system basically includes the process of irradiating recording light (for example, X-rays) while applying a high voltage and accumulating latent image charges, and irradiating the reading light after completing the application of high voltage. Then, it consists of a process of reading out the latent image charge. As the reading light L, a method of scanning the line light source 301 in the electrode direction (see FIG. 11) is optimal, but other methods are also possible.

  Furthermore, a process of sufficiently erasing the unread latent image charges can be combined as necessary. This erasing process is performed by irradiating the entire surface of the panel with erasing light. The entire surface may be irradiated at once, or line light or spot light may be scanned over the entire surface, after the reading process, and / or This is performed before the latent image accumulation process. When irradiating the erasing light, erasing efficiency can be increased by combining high voltage application. Further, by performing “pre-exposure” after applying a high voltage and before irradiating the recording light, it is possible to erase a charge (dark current charge) due to a dark current generated when a high voltage is applied.

  Furthermore, it is known that various charges are accumulated on the electrostatic recording medium before irradiation of recording light due to causes other than these. Since these residual signals affect the image information signal to be output next as an afterimage phenomenon, it is desirable to reduce them by correction.

  As a method of correcting the afterimage signal, a method of adding an afterimage reading process to the above-described image recording and reading process is effective. This afterimage recording process is performed by applying a high voltage without irradiating recording light and then reading an “afterimage image” with the reading light. The afterimage signal can be corrected by subtracting it from the signal. The afterimage reading process is performed before or after the image recording reading process. Further, an appropriate erasing process can be combined before or after the afterimage reading process.

  In the radiation detection substrate 500 as an optical reading type radiation detector, the upper electrode 518 corresponds to the first electrode of the present invention, and the radiation detection layer 522 having the recording photoconductive layer 542 is the photoconductive layer according to the present invention. The lower electrode 520 corresponds to the second electrode according to the present invention, the TCP connection portion 530 corresponds to the extraction electrode of the present invention, and the overcoat layer 552 corresponds to the organic polymer layer of the present invention.

  In the optical reading type radiation detection substrate 500, similarly to the radiation detector 400 described above, the overcoat layer 552 can be configured as follows.

  The overcoat layer 552 as an organic polymer layer has an outer edge portion, that is, a peripheral edge serving as a boundary with another layer is located at a predetermined position, so that the overcoat layer 552 is formed in a predetermined range. It is the structure which covers.

  In the present embodiment, the outer edge portion of the overcoat layer 552 is formed between the region end G1 of the image information acquisition region G from which the image information is acquired and the TCP connection unit 530 among the regions irradiated with the radiation carrying the image information. It is comprised so that it may be located between. A range indicated by an arrow A in FIG. 12A is a range between the region end G1 of the image information acquisition region G and the TCP connection unit 530.

  Preferably, the outer edge portion of the overcoat layer 552 according to this embodiment is outside the image information acquisition region G and has a thickness that is 10% or more of the average thickness of the flat portion of the radiation detection layer 522. Configured to be located within. The flat portion average film thickness of the radiation detection layer 522 is obtained by measuring the film thicknesses of any nine points in the image information acquisition region G of the radiation detection layer 522 and averaging the film thicknesses of the nine points. The film thickness was measured by observing the cross section with a microscope at a magnification of 100 times.

  Note that the range indicated by the arrow B in FIG. 12A is the range outside the image information acquisition region G and within the region having a thickness of 10% or more of the average thickness of the flat portion of the radiation detection layer 522. is there.

  More preferably, the outer edge portion of the overcoat layer 552 according to the present embodiment is located outside the upper electrode 518 and in a region having a thickness of 10% or more of the average thickness of the flat portion of the radiation detection layer 522. Configured to do.

  Note that a range indicated by an arrow C in FIG. 12A is a range outside the upper electrode 518 and in a region having a thickness of 10% or more of the average thickness of the flat portion of the radiation detection layer 522.

  More preferably, the outer edge portion of the overcoat layer 552 is configured to be located outside the upper electrode 518 and in the region where the slope of the end slope of the radiation detection layer 522 is 50% or less.

  The outer edge portion of the overcoat layer 552 is an end slope where the gradient gradually increases from the flat portion of the radiation detection layer 522 toward the outer edge, in a region where the gradient is 50% or less, that is, the gradient is greater than 50%. Is in a moderate range. The gradient of 50% means that, as shown in FIG. 12B, in a right triangle composed of a side along the film thickness direction of the radiation detection layer 522, a side perpendicular to the side, and a hypotenuse, This is a gradient formed by the hypotenuse when the length of the side along the film thickness direction of the detection layer 522 is 1 and the length of the side perpendicular to the side is 2. The gradient was measured by microscopic observation of the cross section at a magnification of 100 times.

  Note that the range indicated by the arrow D in FIG. 12A is the range outside the upper electrode 518 and in the region where the slope of the end slope of the radiation detection layer 522 is 50% or less.

  The radiation detection layer 522 is formed in a wider area than the upper electrode 518. Further, the lower electrode 520 is formed in a region wider than the image information acquisition region G.

Next, a coating solution used for forming the hole injection blocking layer 402 and the overcoat layer 552 will be described. The coating solution can be used when forming an organic polymer layer used for purposes other than the hole injection blocking layer 402 and the overcoat layer 552.
In addition, here, a coating liquid as a discharge liquid used in the ink jet method will be described. However, the coating liquid can be applied to various coating methods such as spray, dip, bar coating, roll coating, spin coating, blade coating, and flexographic printing. It is possible to use.

The coating liquid contains an organic polymer and fullerenes as essential components, and the main solvent of the coating liquid is an aromatic solvent represented by the general formula (1) or (2) and having a boiling point of 150 ° C. or higher. It is a solvent.

(In the general formulas (1) and (2), R1-8 represents hydrogen, halogen, or an alkyl group.)

  In the coating liquid according to the present embodiment, fullerene C60 (frontier carbon Co., Ltd., nanom purple (C60)) is used as the fullerene, and polycarbonate resin (PCz) (Iupilon manufactured by Mitsubishi Gas Chemical Co., Ltd.) as the organic polymer. PCz-400) was used. As the main solvent of the coating solution, the solvents according to Examples A to E shown below were used.

  The coating solution is prepared as follows. First, a certain amount of fullerene C60 and PCz are weighed in a sample bottle. Thereafter, the main solvent was weighed, stirred at room temperature, subjected to ultrasonic treatment at 40 kHz, dissolved or dispersed, and an ink jet coating solution was prepared. In the coating liquid according to the present embodiment, 1.05 wt% of PCz with respect to the main solvent and 30 wt% of C60 with respect to PCz were weighed. When precipitation occurred in the coating solution, it was filtered and used with a 0.45 μm filter.

The process of producing (forming) the organic polymer layer with this coating solution is as follows. First, the above coating liquid is filled in an inkjet head SE-128 manufactured by FUJIFILM Dimatix and discharged onto the coating surface. Thereafter, vacuum drying was performed for 12 hours under a reduced pressure atmosphere of 10 −4 Pa or less to obtain an organic polymer layer having a thickness of 0.2 μm.
Thereafter, the nozzle surface of the inkjet head is wet-wiped before the next discharge is performed.
In the wet wiping, the nozzle surface is wetted with a compatible liquid and the nozzle surface is wiped off. “Compatible” means that two or more substances have an affinity for each other and the substances are mixed. As the compatible liquid, for example, an ink itself or an ink solvent can be used.

(Example A)
In Example A, o-dichlorobenzene was used as the main solvent. As a result, fullerene C60 was precipitated at 25 mg / ml. The boiling point of o-dichlorobenzene was 180 ° C., and the open time in a state packed in SE-128 was 30 minutes.
Here, the open time is a period of time when the ink-jet head is filled with the coating liquid under conditions of 25 ° C. and 50% relative humidity, and is increased to 10, 20, and 30 minutes until no ejection occurs. Is the open time.

(Example B)
In Example B, 1-chloronaphthalene was used as the main solvent. As a result, precipitation occurred with fullerene C60 of 50 mg / ml. In addition, the boiling point of 1-chloronaphthalene was 263 ° C., and the open time in a state packed in SE-128 was 60 minutes.

(Example C)
In Example C, monochlorobenzene was used as the main solvent. As a result, precipitation occurred with fullerene C60 of 6 mg / ml. Moreover, the boiling point of monochlorobenzene was 132 ° C., and the open time in a state packed in SE-128 was 10 minutes.

(Example D)
In Example D, ethanol was used as the main solvent. As a result, precipitation occurred with fullerene C60 of 0.001 mg / ml. The boiling point of ethanol was 78 ° C., and the open time in a state filled in SE-128 was 10 minutes.

(Example E)
In Example E, n-tetradecane was used as the main solvent. As a result, precipitation occurred with fullerene C60 of 0.13 mg / ml. The boiling point of n-tetradecane was 253 ° C., and the open time in a state packed in SE-128 was 60 minutes.

Examples A to C (using an aromatic solvent represented by general formula (1) or general formula (2) as the main solvent) and Examples D and E (general formula (1) or general as the main solvent) Compared with the formula (2) that does not use an aromatic solvent), precipitation of fullerene C60 is drastically caused by using the solvent of the general formula (1) or the general formula (2). It becomes difficult. That is, it can be seen that the solubility or dispersibility of fullerene C60 is improved.
Further, from comparison between Examples A and B and Example C, the use of a main solvent having a boiling point of 150 ° C. or higher increases the open time. That is, in application by the inkjet method, drying of the application liquid in the nozzle can be suppressed, and nozzle clogging can be suppressed. Even in the case of application by other methods, viscosity change due to drying of the application liquid, clogging with a flow path or nozzle for supplying the application liquid, and sticking of the surface of the application member for application are difficult to occur.
Thus, in the formation of the organic polymer layer, it is desirable to use the coating liquid according to Examples A and B. This result was obtained when the hole injection blocking layer 402 as an example of the organic polymer layer in the radiation detector 400 and the overcoat layer 552 as an example of the organic polymer layer in the radiation detection substrate 500 were formed. This does not prevent the use of the coating liquid according to Examples C, D, and E.

In addition, the application by the ink jet method does not require a mask, and the organic polymer layer can be accurately formed in a non-contact manner on the application surface to be applied.
In coating by the ink jet method, the coating solution desirably has a viscosity at 25 ° C. in the range of 1-20 mPa · s, and desirably has a surface tension at 25 ° C. in the range of 15-40 mN / m.
When the viscosity of the coating solution is less than 1 mPa · s, or when the surface tension of the coating solution is less than 15 mN / m, dripping may occur from the nozzle. Further, when the viscosity of the coating liquid exceeds 20 mPa · s or when the surface tension of the coating liquid exceeds 40 mN / m, non-ejection due to nozzle clogging or the like may occur.
For this reason, by setting the viscosity of the coating solution at 25 ° C. within the range of 1-20 mPa · s, it is possible to ensure ejection stability. Further, by setting the surface tension of the coating solution at 25 ° C. in the range of 15-40 mN / m, it is possible to ensure the discharge stability.
The viscosity of the coating solution was measured with a rheometer (Anton Paar: Physica MCR301). The surface tension of the coating solution was measured by Drop Master (manufactured by Kyowa Interface Science Co., Ltd.) as a surface tension meter.

Moreover, in the application | coating by an inkjet method, what has a dilatancy property is desirable for a coating liquid. Dilatancy refers to the property of a liquid whose viscosity increases with increasing shear rate. The relationship between the shear rate of the discharged liquid and the shear viscosity was measured with a rheometer. The measurement was performed twice in the range of the shear rate of 10-1000 [s ⁻¹ ], and the average value is shown in FIG. Since the shear viscosity increases with increasing shear rate, it can be said to be dilatancy.
The exponential approximation in the graph of FIG. 5 is y = 2.2331e ^1E-05x . The shear rate applied to the ejected liquid during ejection from the inkjet head is generally said to be about 10 ⁵ [s ⁻¹ ], and the shear viscosity at that time is expected to be 6.07 [mPa · s]. On the other hand, since the shear rate after landing is considered to be 0 [s ^-1 ], the shear viscosity at that time is expected to be 2.23 [mPa · s]. Since the viscosity decreases after landing, the liquid easily spreads and is clearly suitable for forming a uniform film.

Moreover, in application | coating by the inkjet method, it is desirable for a coating liquid that a contact angle with an application surface is 45 degrees or less. The contact angle of the coating solution was measured by Drop Master (manufactured by Kyowa Interface Science Co., Ltd.) as a contact angle meter.
When the contact angle with the coated surface exceeds 45 °, the organic polymer layer may be formed unevenly because it hardly adheres to the coated surface when landing on the coated surface. Therefore, when the contact angle with the coating surface is 45 ° or less, the coating liquid is likely to become familiar with the coating surface when landing on the coating surface, and a uniform organic polymer layer can be formed.

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

FIG. 1 is a schematic diagram showing the overall configuration of a TFT radiation detector. FIG. 2 is a schematic configuration diagram showing a main part of a TFT radiation detector. FIG. 3 is a cross-sectional view showing the structure of one pixel unit of a TFT radiation detector. FIG. 4 is a plan view showing the structure of one pixel unit of a TFT radiation detector. FIG. 5 is a graph showing the relationship between the shear rate and the shear viscosity of the discharge liquid used for forming the hole injection blocking layer in the TFT type radiation detector. FIG. 6 is a diagram showing a schematic configuration of a radiation detection substrate as an optical reading type radiation detector. FIG. 7 is a diagram showing a schematic structure of the radiation detection lower substrate of the radiation detection substrate shown in FIG. FIG. 8 is a schematic diagram schematically showing the configuration of the radiation detection substrate shown in FIG. FIG. 9 is a view showing a sealing structure for sealing the upper electrode of the radiation detection substrate shown in FIG. FIG. 10 is a block diagram showing a configuration of the charge extraction amplifier and a connection mode between the charge extraction amplifier and an image processing apparatus arranged outside the radiation detection substrate. FIG. 11 is a schematic diagram showing a state when line light is scanned as reading light. 12 is a diagram showing an example in which the configuration of the hole injection blocking layer in the TFT radiation detector shown in FIG. 1 is applied to the radiation detection substrate shown in FIG.

Explanation of symbols

400 radiation detector
401 Bias electrode (first electrode)
402 Hole injection blocking layer (organic polymer layer)
404 photoconductive layer
407a Charge collection electrode (second electrode)
470 Extraction electrode
500 Radiation detection board (radiation detector)
518 Upper electrode (first electrode)
522 Radiation detection layer (photoconductive layer)
520 Lower electrode (second electrode)
530 TCP connection (extraction electrode)
552 Overcoat layer (organic polymer layer)

Claims (8)

A photoconductive layer that generates a charge when irradiated with radiation; and
A first electrode that is formed in a region narrower than the photoconductive layer and applies a bias voltage to the photoconductive layer;
A plurality of second electrodes provided on a side opposite to the side on which the first electrode is provided with respect to the photoconductive layer and collecting charges generated by the photoconductive layer;
An organic polymer layer formed between the first electrode and the photoconductive layer and having charge selectivity;
With
The photoconductive layer is formed so as to cover the plurality of second electrodes,
The outer edge of the organic polymer layer is located outside the first electrode and inside the photoconductive layer;
An extraction electrode disposed outside the photoconductive layer;
A switch element connected to each of the plurality of second electrodes,
The photoconductive layer and the organic polymer layer are formed so as not to cover the extraction electrode,
A radiation detector , wherein charges collected by the plurality of second electrodes are extracted to the extraction electrode via the switch element . 2. The radiation according to claim 1, wherein the organic polymer layer further has an outer edge portion located in a region having a thickness of 10% or more of an average thickness of the flat portion of the photoconductive layer. Detector. 3. The radiation detector according to claim 1, wherein an outer edge portion of the organic polymer layer is further located in a region where a slope of an end slope of the photoconductive layer is 50% or less. 4. .   The second electrode is an amorphous transparent conductive oxide film
  The radiation detector of any one of Claims 1-3 characterized by the above-mentioned. The organic polymer layer contains a hole blocking material,
Apply a positive bias to the first electrode
The radiation detector of any one of Claims 1-4 characterized by the above-mentioned.   At least one of the hole blocking materials is at least one selected from carbon clusters or derivatives thereof.
  The radiation detector according to claim 5.   The photoconductive layer uses amorphous selenium as a main component,
  The organic polymer layer is formed in an insulating polymer layer in a form containing the hole blocking material,
  The carbon cluster is at least one selected from fullerene C60, fullerene C70, oxidized fullerene or a derivative thereof.
  The radiation detector according to claim 6.   An electron injection blocking layer is further provided between the photoconductive layer and the plurality of second electrodes.
  The radiation detector of any one of Claims 1-7 characterized by the above-mentioned.