JP2011212309A - Electromagnetic wave information detection system, electromagnetic wave information detector, and electromagnetic wave information detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain stable electromagnetic wave information even when irradiation is performed with electromagnetic waves for imaging at timing not linked with standby timing before imaging.SOLUTION: The electromagnetic wave information detection system includes: a plurality of photoelectric converters 304 provided with a first electrode 346, a plurality of second electrodes 336, and a photoelectric conversion layer 340; a plurality of normally-on transistors 320 connected to the plurality of second electrodes; a gate voltage control means 242 for controlling the gate voltage of the plurality of transistors; a potential supply means 246 for supplying a predetermined potential to the first electrode; a control means 210 for controlling the gate voltage control means and the potential supply means; and an electromagnetic wave detection means 280 for detecting the electromagnetic waves and transmitting electromagnetic wave detection signals. The potential for imaging is supplied to the first electrode, the gate voltage of the plurality of transistors is turned to 0V as well, and when the electromagnetic wave detection signal is received, control is executed so as to supply the potential for imaging to the first electrode and to also supply an off voltage to the gates of the plurality of transistors.

Description

  The present invention relates to an electromagnetic wave information detection system, an electromagnetic wave information detection device, and an electromagnetic wave information detection method, and more particularly, to an indirect conversion type radiation imaging system, an indirect conversion type radiation imaging device, and a method using the same. The present invention relates to an imaging method.

  In a conventional radiation imaging system using a photoelectric converter, for a while (at least several seconds or more) after the radiation detector is turned on from a sleep state in which the radiation detector having the photoelectric converter is turned off. Is provided with an idling period for stabilizing the dark current of the photoelectric converter. During the idling period, the on-state voltage and off-state voltage (positive voltage and negative voltage) are repeatedly applied to the gate of the thin film transistor to sweep out the dark current stored in the storage capacitor and store the dark current as in the normal read operation. It prevents accumulation in the capacitor (empty reading). In order to shift from the idle reading operation to the imaging operation without degrading the image quality, exposure information from the X-ray source (exposure ready signal, exposure start timing, exposure time), and a portable radiographic image detection device It is necessary to link the driving operation on the side (empty reading, photographing, reading) (see Patent Document 1).

  In recent years, a wireless portable radiographic image detection apparatus has been proposed in order to prevent a handling error (clogging) due to a wired cable of the portable radiographic image detection apparatus. When the portable radiation image detection apparatus and the X-ray source are connected by a wired cable, it is possible to synchronize the exposure information from the X-ray source and the drive operation on the portable radiation image detection apparatus side. . However, there is a delay in signal transmission (several milliseconds) in radio and the X-ray irradiation time from the X-ray source is about 10 milliseconds if it is short, so the X-ray source and the portable radiographic image detection apparatus It is difficult to perform all the interlocking operations by wireless communication.

  Therefore, an X-ray detection means capable of detecting the start and end of X-ray irradiation is built in the wireless portable radiographic image detection apparatus, and the radio-type portable radiographic image detection apparatus and X-ray source are used for the start of the imaging mode Has been proposed (see Patent Document 2).

JP 2002-181942 A JP 2007-151761 A

  However, in this method, it is difficult to link the timing of the standby period before shooting with the shooting / reading timing, and the image mode is forcibly transferred to the shooting mode during idle reading during the standby period before shooting. There is.

  A main object of the present invention is to provide an electromagnetic wave information detection system, an electromagnetic wave information detection device, and an electromagnetic wave information detection method that can obtain stable electromagnetic wave information even when an electromagnetic wave for imaging is irradiated at a timing that is not interlocked with a standby timing before photographing. It is to provide.

According to the present invention,
An electromagnetic wave information detection system comprising an electromagnetic wave generation device that generates an electromagnetic wave, and an electromagnetic wave information detection device that receives the electromagnetic wave and detects information carried on the electromagnetic wave,
The electromagnetic wave information detecting device is
Electromagnetic wave detecting means for detecting at least the start of receiving the electromagnetic wave and transmitting an electromagnetic wave detection start signal;
A first electrode;
A plurality of second electrodes;
A photoelectric conversion layer provided between the first electrode and the plurality of second electrodes;
A plurality of normally-on field effect transistors respectively connected to the plurality of second electrodes;
Gate voltage control means for controlling gate voltages of the plurality of transistors;
A potential providing means for providing a predetermined potential to the first electrode;
Control means connected to the electromagnetic wave detection means, comprising control means for controlling the gate voltage control means and the potential supply means,
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When receiving the electromagnetic wave detection start signal, the gate voltage control unit and the potential are applied so that the imaging potential is supplied to the first electrode and the imaging is started by supplying an off voltage to the gates of the plurality of transistors. An electromagnetic wave information detection system for controlling the providing means is provided.

Preferably, the electromagnetic wave detection means is an electromagnetic wave detection means for detecting the start and end of reception of the electromagnetic wave and transmitting an electromagnetic wave detection signal having information on the start and end of electromagnetic wave detection,
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When the electromagnetic wave detection start information is received by the electromagnetic wave detection signal, the imaging potential is supplied to the first electrode and an off voltage is supplied to the gates of the plurality of transistors to start imaging. The gate voltage control means and the gate voltage control means so as to supply a turn-on voltage to the gates of the plurality of transistors sequentially and perform a read operation when a predetermined period of time has elapsed after receiving the electromagnetic wave detection end information by the transmitted electromagnetic wave detection signal. The potential supply means is controlled.

  Preferably, the active layer of the normally-on field effect transistor is an oxide semiconductor, and more preferably, the oxide semiconductor is IGZO.

  Preferably, the photoelectric conversion layer includes only a charge generation layer using an organic compound as a charge generation agent that generates positive and negative charges when irradiated with electromagnetic waves, and only positive charges generated in the charge generation layer. And a charge transport layer using an organic compound as a charge transport agent for transport.

Preferably, the electromagnetic wave information detection apparatus further includes a signal wiring connected to the plurality of normally-on type field effect transistors, and a connection unit that connects the signal wiring to a predetermined reference potential.
The control means supplies the potential for imaging to the first electrode in advance and sets the plurality of transistors in a standby period before setting the gate voltages of the plurality of transistors to a voltage of −0.5V to 0.5V. The gate voltage control means, the potential supply means, and the gate voltage of the transistor are set to 0 V, the predetermined reference potential is supplied to the first electrode, and the signal wiring is connected to the predetermined reference potential. The connection means is controlled.

  Preferably, the electromagnetic wave information detection device further includes a plurality of storage capacitors respectively connected to the plurality of second electrodes, and starts negative charge generated in the charge generation layer when the imaging is started. To accumulate.

  Preferably, a radiation conversion layer for converting radiation into the electromagnetic wave having a wavelength longer than that of the radiation is further provided.

Moreover, according to the present invention,
Electromagnetic wave detection means for detecting at least the start of reception of electromagnetic waves and transmitting an electromagnetic wave detection start signal;
A first electrode;
A plurality of second electrodes;
A photoelectric conversion layer provided between the first electrode and the plurality of second electrodes;
A plurality of normally-on field effect transistors respectively connected to the plurality of second electrodes;
Gate voltage control means for controlling gate voltages of the plurality of transistors;
A potential providing means for providing a predetermined potential to the first electrode;
A control means connected to the electromagnetic wave detection means, comprising: a control means for controlling the gate voltage control means and the potential supply means;
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When receiving the electromagnetic wave detection start signal, the gate voltage control unit and the potential are applied so that the imaging potential is supplied to the first electrode and the imaging is started by supplying an off voltage to the gates of the plurality of transistors. An electromagnetic wave information detecting device for controlling the providing means is provided.

Preferably, the electromagnetic wave detection means is an electromagnetic wave detection means for detecting the start and end of reception of the electromagnetic wave and transmitting an electromagnetic wave detection signal having information on the start and end of electromagnetic wave detection,
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When the electromagnetic wave detection start information is received by the electromagnetic wave detection signal, the imaging potential is supplied to the first electrode and an off voltage is supplied to the gates of the plurality of transistors to start imaging. The gate voltage control means and the gate voltage control means so as to supply a turn-on voltage to the gates of the plurality of transistors sequentially and perform a read operation when a predetermined period of time has elapsed after receiving the electromagnetic wave detection end information by the transmitted electromagnetic wave detection signal. The potential supply means is controlled.

  Preferably, the active layer of the normally-on field effect transistor is an oxide semiconductor, and more preferably, the oxide semiconductor is IGZO.

  Preferably, the photoelectric conversion layer includes only a charge generation layer using an organic compound as a charge generation agent that generates positive and negative charges when irradiated with electromagnetic waves, and only positive charges generated in the charge generation layer. And a charge transport layer using an organic compound as a charge transport agent for transport.

Preferably, the electromagnetic wave information detection apparatus further includes a signal wiring connected to the plurality of normally-on type field effect transistors, and a connection unit that connects the signal wiring to a predetermined reference potential.
The control means supplies the potential for imaging to the first electrode in advance and sets the plurality of transistors in a standby period before setting the gate voltages of the plurality of transistors to a voltage of −0.5V to 0.5V. The gate voltage control means, the potential supply means, and the gate voltage of the transistor are set to 0 V, the predetermined reference potential is supplied to the first electrode, and the signal wiring is connected to the predetermined reference potential. The connection means is controlled.

  Preferably, the electromagnetic wave information detection device further includes a plurality of storage capacitors respectively connected to the plurality of second electrodes, and starts negative charge generated in the charge generation layer when the imaging is started. To accumulate.

  Preferably, a radiation conversion layer for converting radiation into the electromagnetic wave having a wavelength longer than that of the radiation is further provided.

Moreover, according to the present invention,
Electromagnetic wave detection means for detecting at least the start of reception of electromagnetic waves and transmitting an electromagnetic wave detection start signal;
A first electrode;
A plurality of second electrodes;
A photoelectric conversion layer provided between the first electrode and the plurality of second electrodes;
A plurality of normally-on field effect transistors respectively connected to the plurality of second electrodes;
Gate voltage control means for controlling gate voltages of the plurality of transistors;
A potential providing means for providing a predetermined potential to the first electrode;
An electromagnetic wave information detection method for detecting electromagnetic wave information using an electromagnetic wave information detection apparatus, comprising: a control means connected to an electromagnetic wave detection means, comprising a control means for controlling the gate voltage control means and the potential supply means. There,
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When receiving the electromagnetic wave detection start signal, the gate voltage control unit and the potential are applied so that the imaging potential is supplied to the first electrode and the imaging is started by supplying an off voltage to the gates of the plurality of transistors. An electromagnetic wave information detection method for controlling the provision is provided.

Preferably, the electromagnetic wave detection means is an electromagnetic wave detection means for detecting the start and end of reception of the electromagnetic wave and transmitting an electromagnetic wave detection signal having information on the start and end of electromagnetic wave detection,
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When the electromagnetic wave detection start information is received by the electromagnetic wave detection signal, the imaging potential is supplied to the first electrode and an off voltage is supplied to the gates of the plurality of transistors to start imaging. The gate voltage control means and the gate voltage control means so as to supply a turn-on voltage to the gates of the plurality of transistors sequentially and perform a read operation when a predetermined period of time has elapsed after receiving the electromagnetic wave detection end information by the transmitted electromagnetic wave detection signal. The potential supply means is controlled.

  Preferably, the active layer of the normally-on field effect transistor is an oxide semiconductor, and more preferably, the oxide semiconductor is IGZO.

  Preferably, the photoelectric conversion layer includes only a charge generation layer using an organic compound as a charge generation agent that generates positive and negative charges when irradiated with electromagnetic waves, and only positive charges generated in the charge generation layer. And a charge transport layer using an organic compound as a charge transport agent for transport.

Preferably, the electromagnetic wave information detection apparatus further includes a signal wiring connected to the plurality of normally-on type field effect transistors, and a connection unit that connects the signal wiring to a predetermined reference potential.
The control means supplies the potential for imaging to the first electrode in advance and sets the plurality of transistors in a standby period before setting the gate voltages of the plurality of transistors to a voltage of −0.5V to 0.5V. The gate voltage control means, the potential supply means, and the gate voltage of the transistor are set to 0 V, the predetermined reference potential is supplied to the first electrode, and the signal wiring is connected to the predetermined reference potential. The connection means is controlled.

  Preferably, the electromagnetic wave information detection device further includes a plurality of storage capacitors respectively connected to the plurality of second electrodes, and starts negative charge generated in the charge generation layer when the imaging is started. To accumulate.

  Preferably, a radiation conversion layer for converting radiation into the electromagnetic wave having a wavelength longer than that of the radiation is further provided.

  According to the present invention, there is provided an electromagnetic wave information detection system, an electromagnetic wave information detection device, and an electromagnetic wave information detection method that can obtain stable electromagnetic wave information even when an electromagnetic wave for imaging is irradiated at a timing not interlocked with a standby timing before photographing. The

It is the schematic for demonstrating the indirect conversion type radiation imaging system of preferable 1st Embodiment of this invention. It is a schematic block diagram for demonstrating the electronic cassette of the indirect conversion type radiation imaging system of preferable 1st Embodiment of this invention. It is a schematic longitudinal cross-sectional view for demonstrating the pixel part of the electronic cassette of the indirect conversion type radiation imaging system of preferable 1st Embodiment of this invention. It is a figure for demonstrating the characteristic of the thin-film transistor used for the pixel part of the electronic cassette of the indirect conversion type radiation imaging system of preferable 1st Embodiment of this invention. It is a schematic longitudinal cross-sectional view for demonstrating the radiation detector of the electronic cassette of the indirect conversion type radiation imaging system of preferable 1st Embodiment of this invention. It is a schematic block diagram for demonstrating the radiation generator of the indirect conversion type radiation imaging system of preferable 1st Embodiment of this invention. It is a timing chart for demonstrating the imaging method using the indirect conversion type radiation imaging system of preferable 1st Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  Referring to FIG. 1, an indirect conversion radiation imaging system 100 according to a preferred embodiment of the present invention includes a portable radiation image detection device (hereinafter referred to as “electronic cassette”) 200, a radiation generation device 400, and a display unit. 450.

  The electronic cassette 200 is arranged at a distance from the radiation source 430 of the radiation generating apparatus 400 that generates radiation such as X-rays when capturing a radiation image. At this time, when the subject 50 is located between the radiation source 430 of the radiation generator 400 and the electronic cassette 200 and imaging of the radiographic image is instructed, the radiation source 430 corresponds to the imaging conditions given in advance. A radiation dose 431 is emitted. The X-ray 431 emitted from the radiation source 430 is irradiated on the electronic cassette 200 after carrying image information by passing through the subject 50. In the present embodiment, before the radiation irradiation, when the exposure signal is transmitted from the wireless communication unit 410 of the radiation generation apparatus 400 and the wireless communication unit 272 of the electronic cassette 200 receives the exposure signal, the electronic cassette 200 captures an image. When the preparation operation is started and then the radiation detector 280 detects the radiation 431, the imaging operation is started.

  Next, an electronic cassette 200 of the indirect conversion radiation imaging system 100 according to the preferred embodiment of the present invention will be described with reference to FIG.

  The electronic cassette 200 includes a cassette control unit 210, a radiation detection unit 220, a gate line driver 242, a signal processing unit 244, a bias voltage application circuit 246, an image memory 248, a switching unit 250, and a switching unit 260. , A wireless communication unit 272, a power source 274, and a radiation detector 280. The radiation detector 280 includes a bias voltage application circuit 276 and a detector 284.

  The cassette control unit 210, the radiation detection unit 220, the gate line driver 242, the signal processing unit 244, the bias voltage application circuit 246, the image memory 248, the switching unit 250, the switching unit 260, the wireless communication unit 272, and the radiation detector 280 include The power supply is supplied from the power supply 274. In FIG. 2, wirings for connecting the power supply 274 and these various circuits are omitted.

  The cassette control unit 210 is constituted by a microcomputer, and includes a CPU (Central Processing Unit) 212, a memory 214 including a ROM (Read Only Memory) and a RAM (Random Access Memory), an HDD (Hard Disk Drive), a flash memory, and the like. A nonvolatile storage unit 216 is provided.

  The cassette control unit 210 includes a gate line driver 242, a signal processing unit 244, a bias voltage application circuit 246, an image memory 248, a switching unit 250, a switching unit 260, a wireless communication unit 272, a power source 274, A bias voltage application circuit 276 and a detector 284 are connected, and a gate line driver 242, a signal processing unit 244, a bias voltage application circuit 246, an image memory 248, a switching unit 250, a switching unit 260, a wireless communication unit 272, By controlling the power supply 274 and the bias voltage application circuit 276, the operation of the entire electronic cassette 200 is controlled.

  In the radiation detection unit 220, a radiation charge conversion unit 304 that converts radiation into charges, a storage capacitor 330 that stores the charges converted by the radiation charge conversion unit 304, and a charge stored in the storage capacitor 330 on the substrate 222. A large number of pixel portions 300 each including a thin film transistor (TFT) 320 for reading out are arranged in a matrix.

  A bias electrode 346 (see FIG. 3), which will be described later, is provided on the entire surface of the substrate 222, and the bias electrode 346 (see FIG. 3) is connected to a bias voltage application circuit 246. Under the control of the cassette control unit 210, a bias voltage application circuit 246 applies a reference potential such as a predetermined bias voltage or a ground potential to the bias electrode 346 (see FIG. 3). Note that the electrode 332 (storage capacitor lower electrode 332, see FIG. 3) on the opposite side of the storage capacitor 330 from the radiation charge converter 304 is connected to the ground potential 302.

  A plurality of gate wirings 226 are arranged on the substrate 222 in a certain direction (row direction) for turning on and off the thin film transistor 320 of each pixel unit 300, and in a direction orthogonal to the gate wiring 226 (column direction). A plurality of signal wirings 228 for reading stored charges from the storage capacitor 330 via the thin film transistor 320 that is disposed and turned on are provided.

  Each gate line 226 is connected to the gate line driver 242 via the switching unit 250. In the switching unit 250, a switching circuit 252 that switches between the gate line driver 242 and the ground potential 302 is provided for each gate wiring 226. The switching circuit 252 is switched under the control of the cassette control unit 210 so that each gate wiring 226 is connected to one of the gate line driver 242 and the ground potential 302.

  Each signal wiring 228 is connected to the signal processing unit 244 via the switching unit 260. In the switching unit 260, a switching circuit 262 that switches between the signal processing unit 244 and the ground potential 302 is provided for each signal wiring 228. The switching circuit 262 is switched under the control of the cassette control unit 210 so that each signal wiring 228 is connected to one of the signal processing unit 244 and the ground potential 302.

  While being irradiated with radiation, the thin film transistors 320 of each pixel unit 300 are all turned off by a signal supplied from the gate line driver 242 via the gate wiring 226 under the control of the cassette control unit 210, and the radiation charge Charges corresponding to the charges photoelectrically converted from radiation by the conversion unit 304 are stored in the storage capacitors 330 of the pixel units 300. After the irradiation of radiation, the thin film transistor 320 of each pixel unit 300 is sequentially turned on in units of rows by a signal supplied from the gate line driver 242 via the gate wiring 226 under the control of the cassette control unit 210. The charge accumulated in the storage capacitor 330 of the pixel portion 300 in which the thin film transistor 320 is turned on is transmitted as an analog electric signal through the signal wiring 228 and input to the signal processing portion 244. As described above, the charges accumulated in the storage capacitor 330 of each pixel unit 300 are sequentially read out in units of rows. The analog electric signal input to the signal processing unit 244 is converted into digital image data by an A / D converter (not shown) in the signal processing unit 244.

  An image memory 248 is connected to the signal processing unit 244, and digital image data output from the signal processing unit 244 is sequentially stored in the image memory 248 under the control of the cassette control unit 210. The image memory 248 has a storage capacity capable of storing image data for a plurality of frames, and image data obtained by imaging is sequentially stored in the image memory 248 every time a radiographic image is captured.

  The image memory 248 is connected to the cassette control unit 210. Under the control of the cassette control unit 210, the image data stored in the image memory 248 is sent to the storage unit 216 and recorded.

  A wireless communication unit 272 is connected to the cassette control unit 210. The cassette control unit 210 controls the wireless communication unit 272 to transmit and receive various types of information by wireless communication with the radiation generation device 400 via a wireless communication unit 410 (see FIG. 6) described later of the radiation generation device 400. I do.

  The radiation detector 280 includes a radiation charge converter 282, a bias voltage application circuit 276, and a detector 284. One electrode of the radiation charge converter 282 is connected to one end of the bias voltage application circuit 276, and the other electrode of the radiation charge converter 282 is connected to the ground potential 302. The other end of the bias voltage application circuit 276 is connected to one end of the detector 284, and the other end of the detector 284 is connected to the ground potential 302. While the bias voltage is applied to the radiation charge converter 282 by the bias voltage application circuit 276, the detector 284 detects the rise at the moment when the radiation is incident on the radiation charge converter 282. A detection signal from the detector 284 is sent to the cassette control unit 210.

  Next, each pixel unit 300 of the radiation detection unit 220 will be described with reference to FIG.

  A storage capacitor 330 and a thin film transistor 320 are provided on one surface of the flexible substrate 310. The storage capacitor 330 is configured by a storage capacitor upper electrode 334, a storage capacitor lower electrode 332, and a dielectric layer 314 between these electrodes (this dielectric layer 314 also functions as an insulating film). The thin film transistor 320 is formed so as to cover the drain electrode 324, the source electrode 326 connected to the storage capacitor upper electrode 334, an active layer (channel layer) 328 between the source electrode 326 and the drain electrode 324, and the active layer 328. And a gate electrode 322 at a position facing the active layer 328 with a dielectric layer 314 functioning as an insulating film interposed therebetween.

  An interlayer insulating film 338 is provided over the storage capacitor 330 and the thin film transistor 320. A contact hole 339 is provided in the interlayer insulating film 338 on the storage capacitor upper electrode 334. A charge collection electrode (lower electrode) 336 is provided on the interlayer insulating film 338. The charge collection electrode 336 is a pixel electrode and is provided for each pixel unit 300. The charge collection electrode 336 is connected to the storage capacitor upper electrode 334 via the contact hole 339.

  A polymer undercoat layer 312 is provided on the charge collection electrode 336. On the polymer undercoat layer 312, a charge generation layer 344, a charge transport layer 342, and a bias electrode 346 are provided in this order. The charge generation layer 344 and the charge transport layer 342 constitute an organic photoelectric conversion layer 340. A phosphor layer 350 is provided on the bias electrode 346 via an interlayer insulating film 316.

The flexible substrate 310 is made of a laminate of thin glass and polyethylene naphthalate (PEN). The gate electrode 322 and the storage capacitor lower electrode 332 are made of Mo. The dielectric layer 314 is made of silicon dioxide. The source electrode 326, the drain electrode 324, and the storage capacitor upper electrode 334 are made of IZO. The active layer 328 is made of IGZO (In-Ga-Zn-Oxide). The protective layer 329 is made of amorphous Ga ₂ O ₃ . The interlayer insulating film 338 is made of acrylic resin. The charge collection electrode 336 is made of IZO. The polymer undercoat layer 116 is formed by applying and drying an alcohol-soluble polyamide, and has a function of firmly joining the charge collection electrode 336 and the charge generation layer 344.

  The charge generation layer 344 includes a charge generation agent that generates positively charged holes and negatively charged electrons and a polymer binder when irradiated with electromagnetic waves. Dibromoanthanthrone pigment is used as a charge generating agent, and polyvinyl butyral resin is used as a polymer binder. The charge transport layer 342 includes a charge transport agent that transports only holes and a polymer binder. N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine is used as the charge transport agent and polycarbonate is used as the polymer binder. ing. The bias electrode 346 is made of IZO.

The interlayer insulating film 316 is made of an acrylic double-sided adhesive tape. The phosphor layer 350 is made of KODAK Lanex Regular (Ga ₂ O ₂ S: Tb), which is a phosphor sheet of KODAK. The phosphor layer 350 converts radiation transmitted through the subject into visible light when the subject to be imaged is irradiated with radiation. The phosphor layer 350 and the organic photoelectric conversion layer 340 constitute a radiation charge conversion unit 304.

  The radiation detection unit 220 is manufactured as follows. First, Mo is sputtered to a thickness of 40 nm on a flexible substrate 310 obtained by bonding a thin glass with a thickness of 0.15 mm and PEN with a thickness of 0.1 mm, and patterned by photolithography and wet etching. Thus, the gate electrode 322 and the storage capacitor lower electrode 332 were formed.

  On top of this, silicon dioxide was sputtered to a thickness of 200 nm to form a dielectric layer 314 that also served as an insulating film.

  Next, IZO was sputtered to a thickness of 200 nm without introducing oxygen, and patterned by photolithography and wet etching to form a source electrode 326, a drain electrode 324, and a storage capacitor upper electrode 334. The edges where the source electrode 326 and the drain electrode 324 face each other were set to have a taper angle of 25 °.

  Next, IGZO was sputtered to a thickness of 10 nm. The thin film transistor 320 is a normally-on field effect transistor by adjusting the flow rate of oxygen introduced during sputtering. The active layer 328 was formed by patterning the IGZO sputtered by photolithography and wet etching. FIG. 4 shows Id-Vgs characteristics of the thin film transistor 320. The vertical axis represents the drain current (Id), and the horizontal axis represents the gate-source voltage (Vgs). A high on-current is obtained when the gate-source voltage Vgs is 0V. Also, the off current is a small value.

Next, amorphous Ga ₂ O ₃ was formed by sputtering to a thickness of 10 nm, and only the region covering the active layer 328 was left to form the protective layer 329.

  Next, an interlayer insulating film 338 made of acrylic resin was applied, and a contact hole 339 was formed in the interlayer insulating film 338 above the storage capacitor upper electrode 334.

  Next, IZO was deposited and patterned to a thickness of 40 nm to form a charge collection electrode (lower electrode) 336. The charge collection electrode 336 is connected to the storage capacitor upper electrode 334 through a contact hole 339.

  Next, the alcohol-soluble polyamide was spin-coated on the charge collection electrode 336 to a thickness of 0.1 μm and dried to form the polymer undercoat layer 312.

  Next, a dibromoanthanthrone pigment and polyvinyl butyral resin added to and dispersed in cyclohexanone at a mass ratio of the former: the latter of 50:50 were applied onto the polymer subbing layer 312 by spin coating, and the thickness was reduced to 0. A .5 μm charge generation layer 344 was formed.

  Next, 3.5 g of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine as a charge transport agent and polycarbonate (molecular weight) : About 35,000 to 40,000) 6.5 g was dissolved in 35 g of methylene chloride and coated on the charge generation layer 344 by bar coating to form a charge transport layer 342. After drying at 135 ° C. for 1 hour, the thickness of the charge transport layer 342 was measured to be 2 μm.

  Next, IZO was deposited to a thickness of 100 nm on the charge transport layer 342 to form a bias electrode layer 346.

Next, KODAK Lanex Regular (Ga ₂ O ₂ S: Tb 380 μm), which is a phosphor sheet of KODAK, was prepared, and the phosphor sheet and the bias electrode layer 346 were bonded to an adhesive layer 316 (thickness of acrylic double-sided adhesive tape). The radiation detection part 220 of the electronic cassette 200 was produced.

  In the electronic cassette 200 according to the present embodiment, the radiation transmitted through the subject enters the phosphor layer 350 and is converted into visible light that is an electromagnetic wave having a wavelength longer than that of the radiation. The converted visible light is converted into holes having a positive charge and electrons having a negative charge in the organic photoelectric conversion layer 340. The holes converted by the organic photoelectric conversion layer 340 move through the charge transport layer 342 due to a potential difference applied between the bias electrode 346 and the charge collection electrode 336 and are collected by the bias electrode 346. The electrons converted by the organic photoelectric conversion layer 340 are stored by a storage capacitor upper electrode 334 connected to the charge collection electrode 336, a storage capacitor lower electrode 332, and a dielectric layer 314 between these electrodes. It is stored in the capacity 330. Since the storage capacitor upper electrode 334 and the drain electrode 324 are connected, by applying an on voltage to the gate electrode 322 to turn on the thin film transistor 320, the charge accumulated in the storage capacitor 30 is transferred from the drain electrode 324. The signal wiring 228 (see FIG. 2) is transmitted and input to the signal processing unit 244 (see FIG. 2). After being input to the signal processing unit 244 (see FIG. 2), it is appropriately A / D converted and stored in the image memory 248. The radiation image information stored in the image memory 248 is stored in the storage unit 216 of the cassette control unit, and then the radiation generation apparatus 400 via the wireless communication unit 272 and the wireless communication unit 410 (see FIG. 6) described later. (See FIG. 6) and displayed as a visible image on a display unit 452 (see FIG. 6) of a display device 450 (see FIG. 6) described later.

  Next, the radiation detector 280 will be described with reference to FIG.

  The radiation charge converter 282 of the radiation detector 280 uses a part of the radiation detector 220. Therefore, since each component is the same as the component of the radiation detection part 220, description is abbreviate | omitted. However, an electrode of the same layer as the bias electrode 346 of the radiation detection unit 220 and provided apart from the bias electrode 346 is used as the bias electrode 346 ′ of the radiation charge converter 282, and An electrode of the same layer as the charge collection electrode (lower electrode) 336 and provided separately from the lower electrode 336 is used as the lower electrode 336 ′ of the radiation charge converter 282. The bias electrode 346 'and the lower electrode 336' are provided to face each other. The stacked body from the phosphor layer 350 to the lower electrode 336 ′ constitutes the radiation charge converter 282.

  The bias electrode 346 ′ of the radiation charge converter 282 is connected to one end of the bias voltage application circuit 276, and the lower electrode 336 ′ of the radiation charge converter 282 is connected to the ground potential 302. The other end of the bias voltage application circuit 276 is connected to one end of the detector 284, and the other end of the detector 284 is connected to the ground potential 302. As the detector 284, a current-voltage conversion amplifier is used.

  A bias voltage is applied to the radiation charge converter 282 by the bias voltage application circuit 276 to give a predetermined potential difference between the bias electrode 346 'and the lower electrode 336'. When radiation is incident on the phosphor layer 350, the phosphor layer 350 is converted into visible light that is an electromagnetic wave having a wavelength longer than that of the radiation. The converted visible light is converted into holes having a positive charge and electrons having a negative charge in the organic photoelectric conversion layer 340. The holes converted by the organic photoelectric conversion layer 340 move through the charge transport layer 342 by the potential difference applied between the bias electrode 346 ′ and the lower electrode 336 ′, and are collected on the bias electrode 346 ′. By detecting the charge photoelectrically converted by the radiation charge converter 282 with the detector 284, the rising at the moment when the radiation enters the radiation charge converter 282 is detected.

  Next, with reference to FIG. 6, the radiation generator 400 of the indirect conversion type radiation imaging apparatus 200 according to a preferred embodiment of the present invention will be described.

  The radiation generation apparatus 400 includes a display 414 that displays an operation menu, a captured radiation image, and the like, an operation panel 418 that receives various information and operation instructions, and X as radiation. A radiation source 430 for outputting a line.

  The radiation generation apparatus 400 also stores a CPU 402 that controls the operation of the entire radiation generation apparatus 400, a ROM 404 that stores various programs including a control program in advance, a RAM 406 that temporarily stores various data, and various data. HDD 408 to be held, a radiation source control unit 432 that controls the radiation source 430, an image signal output unit 420 that outputs an image signal to the display device 450, and a wireless communication unit 272 (see FIG. 2) of the electronic cassette 200 2), a wireless communication unit 410 that transmits and receives various types of information to and from the electronic cassette 200 via wireless communication, a display driver 412 that controls display of various types of information on the display 414, and operations on the operation panel 418. And an operation input detection unit 416 for detecting a state.

  The CPU 402, ROM 404, RAM 406, HDD 408, wireless communication unit 410, display driver 412, operation input detection unit 416, image signal output unit 420 and radiation source control unit 432 are connected to each other via a system bus 440. Therefore, the CPU 402 can access the ROM 404, RAM 406, and HDD 408, controls transmission / reception of various information to / from the electronic cassette 200 via the wireless communication unit 410, and performs various operations on the display 414 via the display driver 412. Control of information display, display of various information on the display device 450 via the image signal output unit 420, and control of the radiation source 430 via the radiation source control unit 432 can be performed. The CPU 402 can also grasp the operation state of the user with respect to the operation panel 418 via the operation input detection unit 416.

  Next, with reference to the timing chart of FIG. 7, a method for imaging using the indirect conversion radiation imaging system 100 according to the preferred embodiment of the present invention will be described.

  In the standby period before imaging, the cassette control unit 210 of the electronic cassette 200 controls the switching circuit 252 to connect each gate wiring 346 to the ground potential 302 and apply 0 V to the gates of all the thin film transistors 320. Then, the bias voltage application circuit 246 is controlled to apply 0 V to the bias electrode 346 of the radiation charge conversion unit 304 (given a ground potential), and the switching circuit 262 is controlled to control each signal line 228. It is connected to the ground potential 302, and the bias voltage application circuit 276 is controlled to apply 0 V to the bias electrode 346 ′ of the radiation detector 280 (given a ground potential).

  When the imaging person performs an imaging instruction operation for instructing imaging by operating the operation panel 418 of the radiation generating apparatus 400, the CPU 402 controls the wireless communication unit 410 to transmit to the wireless communication unit 272 of the electronic cassette 200 by wireless communication. An exposure signal C1 is transmitted.

  When the wireless communication unit 272 receives the exposure signal C1, the cassette control unit 210 of the electronic cassette 200 controls the bias voltage application circuit 246 to apply an imaging bias (for example, −20V) to the bias electrode 346 of the radiation charge conversion unit 304. ) And the bias voltage application circuit 276 is controlled to apply a bias (for example, −20 V) to the bias electrode 346 ′ of the radiation detector 280 (imaging preparation period).

  When a predetermined time has elapsed after the transmission of the exposure signal C <b> 1 is started, the CPU 402 of the radiation generation apparatus 400 controls the radiation source control unit 432 to cause the radiation source 430 to emit X-rays. The predetermined time is set to be equal to or longer than the time during which the radiation charge conversion unit 304 of the electronic cassette 200 is stabilized.

  X-rays emitted from the radiation source 430 are detected by the radiation detector 280 of the electronic cassette 200, and the radiation detector 280 transmits a radiation detection signal C <b> 2 to the cassette control unit 210.

  The cassette control unit 210 that has received the radiation detection signal C2 controls the switching circuit 252 to switch the connection of each gate wiring 346 to the gate line driver 242, and controls the gate line driver 242 via the gate wiring 346. An off voltage (−10 V) is applied to the gate electrodes of all the thin film transistors 320 to turn off all the thin film transistors 320 and start imaging.

  The X-ray 431 emitted from the radiation source 430 passes through the subject 50 to carry image information of the subject 50 and then reaches the radiation detection unit 220 of the electronic cassette 200, and each pixel unit of the radiation detection unit 220. The charges are converted into charges by the radiation charge conversion unit 304 of 300, and charges corresponding to the dose of the irradiated X-rays are stored in the storage capacitor 330.

  When a predetermined time has elapsed since the start of X-ray emission, the CPU 402 of the radiation generation apparatus 400 controls the radiation source control unit 432 to stop the radiation source 430 from emitting X-rays.

  The stop of the X-ray is detected by the radiation detector 280 of the electronic cassette 200, and the radiation detector 280 stops transmitting the radiation detection signal C2 to the cassette control unit 210.

  The cassette control unit 210 controls the switching circuit 262 to switch the connection of each signal wiring 228 to the signal processing unit 244 after the elapse of a predetermined period from the detection of the falling edge of the radiation detection signal C2, and the gate line driver 242 is turned on. The gate line driver 242 applies a turn-on voltage (+10 V) to each gate line 346 in order line by line, and the thin film transistor 320 connected to each gate line 346 is turned on line by line.

  When the thin film transistor 320 connected to each gate line 346 is turned on line by line, the charge accumulated in each storage capacitor 330 sequentially line by line flows out to each signal line 228 as a charge signal. The charge accumulated in the storage capacitor 330 is transmitted as an analog electric signal through the signal wiring 228 and input to the signal processing unit 244. As described above, the charges accumulated in the storage capacitor 330 of each pixel unit 300 are sequentially read out in units of rows. The analog electrical signal input to the signal processing unit 244 is converted into digital image data by an A / D converter (not shown) in the signal processing unit 244 and stored in the image memory 248.

  When the reading of the image information for one frame (one sheet) is completed, the cassette control unit 210 controls the switching circuit 252 to switch the connection of each gate wiring 346 to the ground potential 302 and to the gates of all the thin film transistors 320. 0 V is applied, the bias voltage application circuit 246 is controlled to apply 0 V to the bias electrode 346 of the radiation charge converter 304 (giving a ground potential), and the switching circuit 262 is controlled to connect each signal line 228. Is switched to the ground potential 302, and the bias voltage application circuit 276 is controlled to apply 0 V to the bias electrode 346 ′ of the radiation detector 280 (giving the ground potential) to enter a standby state before imaging.

  When the reading of the image information for one frame (one sheet) is completed, the cassette control unit 210 transmits the image information stored in the image memory 248 to the storage unit 216 of the cassette control unit 210 frame by frame. .

  The image information stored in the storage unit 216 is transmitted to the radiation generation apparatus 400 via the wireless communication units 272 and 410 and stored in the HDD 408. The image information stored in the HDD 408 is displayed on the display unit 452 of the display device 450 via the image signal output unit 420.

  In the above embodiment, a normally-on transistor is used as the thin film transistor 320, and 0 V is applied to the gate electrodes of all the thin film transistors 320 in the imaging preparation period before imaging. When 0 V is applied to the gate electrode of a normally-on transistor, the source and drain can be brought into a conductive state. In addition, it is not necessary to use a power source in order to apply 0 V to the gate electrode, and the gate electrode may be connected to the ground potential. Therefore, the source and drain can be brought into a conductive state without a power source. As a result, dark current when a bias voltage is applied to the bias electrode 346 of the radiation charge conversion unit 304 can be swept out through the thin film transistor 320, and accumulation of dark current in the storage capacitor 330 can be prevented.

  At this time, since the gate electrode is connected to the ground potential and a constant 0 V is applied to the gate electrode, charging / discharging is not repeated and there is no wasteful power consumption. In particular, since a battery is used in a wireless electronic cassette, it is necessary to reduce the power consumed during periods other than imaging. In particular, a wireless electronic cassette (wireless) used at an emergency site is required. Type) is always set to the imaging preparation state (imaging ready state), and it is required to reduce power consumption in the imaging preparation state as much as possible. Therefore, the electronic cassette 200 of the present embodiment is It is particularly preferably used for such applications.

  In addition, since the voltage applied to the gate electrode of the thin film transistor 320 is 0 V in the imaging preparation state, it does not become a stress voltage, and the threshold shift of the thin film transistor 320 hardly occurs.

  In the standby imaging preparation state, 0V is applied to the gate electrodes of all the thin film transistors 320, and there is no gate voltage scanning. Therefore, an artifact is generated due to a difference between the standby imaging preparation timing and imaging timing before imaging. Absent. Therefore, stable image information can be obtained even when X-rays for imaging are irradiated at a timing that is not synchronized with the standby timing before imaging.

  Note that, in the above embodiment, in the imaging preparation state during standby, 0 V is applied to the gate electrodes of all the thin film transistors 320, but a voltage within the range of −0.5 V to 0.5 V (preferably a constant voltage). ) Can be made close to a conductive state between the source and the drain, and the dark current when the bias voltage is applied to the bias electrode 346 of the radiation charge converter 304 is swept out through the thin film transistor 320. This can prevent dark current from being stored in the storage capacitor 330. Furthermore, if a constant voltage is applied, charging / discharging is not repeated and there is no wasteful power consumption. In addition, in the imaging preparation state, the voltage applied to the gate electrode of the thin film transistor 320 is a voltage in the range of −0.5 V to 0.5 V, so that it does not become a stress voltage and the threshold shift of the thin film transistor 320 hardly occurs. Further, when a constant voltage within a range of −0.5 V or more and 0.5 V or less is applied to the gate electrodes of all the thin film transistors 320 in the standby imaging preparation state, there is no gate voltage scanning, and standby before imaging. It is possible to eliminate the occurrence of artifacts due to the difference between the timing of imaging preparation and the timing of imaging.

  In the above embodiment, when an imager performs an imaging instruction operation for instructing imaging by operating the operation panel 418 of the radiation generating apparatus 400, the electronic cassette 200 is wirelessly communicated from the wireless communication unit 410 of the radiation generating apparatus 400. When the exposure signal C1 is transmitted to the wireless communication unit 272 and the wireless communication unit 272 receives the exposure signal C1, imaging is performed by applying an imaging bias (eg, −20 V) to the bias electrode 346 of the radiation charge conversion unit 304. Enter the preparation period. Then, when a predetermined time elapses after the transmission of the exposure signal C1 is started, the radiation source 430 of the radiation generating apparatus 400 emits X-rays. Therefore, it is not necessary for the imager to monitor the generation of an exposure induction signal or the like, or to operate the radiation generation switch at a timing in accordance with the exposure induction signal. There is little mental restraint on the photographer in terms of timing.

  In the above embodiment, X-rays emitted from the radiation source 430 are detected by the radiation detector 280 of the electronic cassette 200, and all the thin film transistors 320 are turned off by the rise of the radiation detection signal C2 transmitted from the radiation detector 280. Then, imaging is started. As described above, in this embodiment, normally-on transistors are used as the thin film transistors 320. In the standby imaging preparation state, 0 V is applied to the gate electrodes of all the thin film transistors 320, and gate voltage scanning is performed. Therefore, even if all of the thin film transistors 320 are turned off and imaging is started by the rise of the radiation detection signal C2 detected by the radiation detector 280 from the X-ray emitted from the radiation source 430, the imaging apparatus is in a standby state before imaging. Stable image information can be obtained without the occurrence of artifacts due to the difference between the timing of imaging preparation and the timing of imaging.

  In the above-described embodiment, when the wireless communication unit 272 receives the exposure signal C1 through wireless communication, an imaging bias (for example, −20 V) is applied to the bias electrode 346 of the radiation charge conversion unit 304 in the imaging preparation period. However, it is also possible to apply an imaging bias (for example, −20 V) to the bias electrode 346 of the radiation charge converter 304 at an arbitrary timing so as to enter an imaging preparation period. In the above embodiment, normally-on type transistors are used for the thin film transistors 320, and 0 V is applied to the gate electrodes of all the thin film transistors 320 in the standby imaging preparation state. After applying an imaging bias (for example, −20 V) to the electrode 346 and entering the imaging preparation period, after the time longer than the time when the radiation charge conversion unit 304 becomes stable, imaging is performed no matter when the imaging is started. Stable image information can be obtained without the occurrence of artifacts due to a difference between the previous imaging preparation timing during standby and the imaging timing.

  However, the characteristics of the organic photoelectric conversion layer 340 used in the above embodiment change if the imaging bias is kept applied. If a photoelectric conversion film whose characteristics change when such an imaging bias is applied is used, it is better to apply an imaging bias immediately before imaging and enter an imaging preparation period. When the exposure signal C1 is previously transmitted by wireless communication and the exposure signal C1 is received, the method of entering the imaging preparation period is preferable.

  In addition, when the exposure signal C1 is transmitted by wireless communication and the exposure signal C1 is received before imaging as described above, in the case of the system in which the imaging preparation period starts, X-ray irradiation starts from the rise of the exposure signal C1. If the time information until is transmitted together with the exposure signal C1 by wireless communication, imaging may be started based on the time information. In that case, even if it does not use the method of starting imaging according to the radiation detection signal C2 transmitted from the radiation detector 280, the occurrence of artifacts due to the difference between the imaging preparation timing in standby and imaging timing before imaging is generated. Can be suppressed. A normally-on type transistor is used as the thin film transistor 320, and in a standby imaging preparation state, a normally-off type transistor is used instead of a method of applying 0 V to the gate electrodes of all the thin film transistors 320. In the imaging preparation state, even when a positive voltage and a negative voltage are repeatedly applied to the gate electrode of the thin film transistor 320, it is possible to suppress the occurrence of artifacts due to a difference in imaging preparation timing and imaging timing during standby before imaging.

  In the above embodiment, the stop of X-rays is detected by the radiation detector 280 of the electronic cassette 200, and reading is performed after a predetermined period has elapsed since the falling of the radiation detection signal C2 by the radiation detector 280 is detected. However, if the imaging time information is transmitted together with the exposure signal C1 by wireless communication, reading may be started based on the information.

  Note that the timing at which imaging bias is started to be applied to the bias electrode of the radiation charge converter 346, the timing at which all the thin film transistors 320 are turned off and the accumulation into the storage capacitor 330 is started, and the thin film transistors 320 in the first row are turned on for reading. It is preferable to correct the offset (accumulation of dark current) from the image based on the timing of starting the image.

  IGZO is used for the active layer 328 of the thin film transistor 320 in the above embodiment, but another oxide semiconductor, for example, an oxide semiconductor such as IZO (In-Zn-Oxide) can also be used. Using these oxides, a normally-on transistor with a large on-state current can be easily created, and the off-state current during off-bias can be very low, realizing a transistor with a high on-off ratio. can do. Among oxides, IGZO is particularly preferably used because it is excellent in control of threshold voltage and environmental stability. Note that amorphous Si can be used for the active layer 328 of the normally-on thin film transistor 320. However, when it is not doped at a high concentration, the normally-on type is not obtained. It is difficult to achieve both normally-on operation and low OFF current, for example, it is not possible, and this is not very preferable.

  Although the organic photoelectric conversion film is used for the photoelectric conversion layer 340 in the above embodiment, amorphous Si or amorphous Se can also be used. When amorphous Si or amorphous Se is used for the photoelectric conversion layer 320, an imaging voltage is applied from the standby period before imaging to the imaging preparation period, imaging period, and readout period. When amorphous Si or amorphous Se is used, it is preferable that the imaging voltage is continuously applied because the voltage is not stable unless the voltage is continuously applied.

  On the other hand, in the case of an organic photoelectric conversion film, the longer the state in which the charge collection electrode 336 and the bias electrode 346 on both sides of the photoelectric conversion layer 340 are short-circuited, the more stable. Also, when the image is not taken, the power is not consumed if the short circuit is set as much as possible. Further, in the case of the organic photoelectric conversion film, since the dark current itself is less than that in the case of amorphous Si or amorphous Se, the time from the application of the imaging bias to the bias electrode 346 until stabilization becomes shorter. In the above embodiment, in the standby period before imaging, 0 V is applied to the gates of all the thin film transistors 320, 0 V is applied to the bias electrode 346 of the radiation charge conversion unit 304, and each signal line 228 is grounded. 302, the charge collection electrode 336 and the bias electrode 346 are short-circuited.

  Although gadolinium sulfate (GOS: Tb) is used for the phosphor sheet 126 of the above embodiment and the phosphor layer 350 of the second embodiment, cesium iodide (CsI: Tl) is preferably used. .

  In the above embodiment, the phosphor layer 350 is used. However, if these scintillators are not used, the indirect conversion radiation imaging system 100 of the above embodiment uses visible light such as a visible light contact optical imaging device. It can be used as an imaging system.

  The charge transport layer 342 in the above embodiment is a layer that is transparent to the electromagnetic waves that generate charges in the charge generation layer 344. Depending on the electromagnetic waves that generate charges in the charge generation layer, the charge transport layer has no charge. Does not occur.

  The charge generation layer 344 of the above embodiment contains a charge generator and a polymer binder as constituent components. Examples of the charge generator include phthalocyanine dyes such as metal phthalocyanine and metal-free phthalocyanine or phthalocyanine pigments, Preferably used are phthalocyanine dyes or naphthalocyanine pigments, indigo dyes, quinacridone dyes, anthraquinone dyes, for example, anthanthrone dyes such as dibromoanthanthrone, perylene dyes, such as azo dyes such as monoazo dyes, bisazo dyes, trisazo dyes, and cyanine dyes. It is done.

  Examples of the polymer binder used for the charge generation layer 344 include polyvinyl butyral.

The ratio between the charge generating agent and the polymer binder is preferably selected from the range of 80:20 to 20:80 in terms of the former: latter mass ratio for the reason of achieving both sensitivity stability and stability over time. More preferably, it is selected from the range of 45:55 to 25:75.
A dispersion in which a charge generator is dispersed in a solution of a polymer binder in a solvent is prepared, and this is spin-coated, dried (also referred to as baking), and the solvent is evaporated to form a charge generation layer 344. The

  The charge transport layer 342 of the above embodiment contains a charge transport agent and a polymer binder as constituent components.

  As the charge transport agent, those known as hole transport materials are preferably used. For example, triarylamine compound, benzidine compound, pyrazoline compound, styrylamine compound, hydrazone compound, triphenylmethane compound, carbazole compound, polysilane compound, thiophene compound, phthalocyanine compound, cyanine compound, merocyanine compound, oxonol compound, polyamine compound, indole Compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), nitrogen-containing heterocyclic compounds The metal complex etc. which it has as can be used. Note that the present invention is not limited thereto, and any organic compound having an ionization potential smaller than that of the organic compound used as the charge generating agent can be used as the charge transporting agent.

  Examples of the polymer binder used for the charge transport layer 342 include polycarbonate, polyvinyl butyral, acrylic acid ester homopolymers or copolymers with other copolymerizable monomers, methacrylic acid ester homopolymers or other copolymerizable monomers, and the like. And copolymers with styrene homopolymers or other copolymerizable monomers such as acrylonitrile, polysulfone and the like.

  The charge transport layer is formed by preparing a solution in which a charge transport agent and a polymer binder are dissolved in a solvent, applying this solution onto the charge generation layer by, for example, dip coating or spin coating, and baking to evaporate the solvent. Is done.

  While various typical embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Accordingly, the scope of the invention is limited only by the following claims.

50 Subject 100 Indirect Conversion Radiation Imaging System 200 Electronic Cassette 210 Cassette Control Unit 212 CPU
214 Memory 216 Storage unit 220 Radiation detection unit 222 Substrate 226 Gate wiring 228 Signal wiring 242 Gate line driver 244 Signal processing unit 246 Bias voltage application circuit 248 Image memory 250 Switching unit 252 Switching circuit 260 Switching unit 262 Switching circuit 272 Wireless communication unit 274 Power supply 276 Bias voltage application circuit 280 Radiation detector 282 Radiation charge converter 284 Detector 300 Pixel unit 302 Ground potential 304 Radiation charge conversion unit 310 Flexible substrate 312 Polymer undercoat layer 314 Dielectric layer 316 Interlayer insulating film 320 Thin film transistor 322 Gate electrode 324 Drain electrode 326 Source electrode 328 Active layer 329 Protective layer 330 Storage capacitor 332 Storage capacitor lower electrode 334 Storage capacitor upper electrode 336 Charge collection electrode (lower electrode)
338 Interlayer insulating film 339 Contact hole 340 Organic photoelectric conversion layer 342 Charge transport layer 344 Charge generation layer 346 Bias electrode 350 Phosphor layer 400 Radiation generation device 402 CPU
404 ROM
406 RAM
408 HDD
410 Wireless communication unit 412 Display driver 414 Display 416 Operation input detection unit 418 Operation panel 420 Image signal output unit 430 Radiation source 431 X-ray 432 Radiation source control unit 450 Display device 452 Display unit

Claims (24)

An electromagnetic wave information detection system comprising an electromagnetic wave generation device that generates an electromagnetic wave, and an electromagnetic wave information detection device that receives the electromagnetic wave and detects information carried on the electromagnetic wave,
The electromagnetic wave information detecting device is
Electromagnetic wave detecting means for detecting at least the start of receiving the electromagnetic wave and transmitting an electromagnetic wave detection start signal;
A first electrode;
A plurality of second electrodes;
A photoelectric conversion layer provided between the first electrode and the plurality of second electrodes;
A plurality of normally-on field effect transistors respectively connected to the plurality of second electrodes;
Gate voltage control means for controlling gate voltages of the plurality of transistors;
A potential providing means for providing a predetermined potential to the first electrode;
Control means connected to the electromagnetic wave detection means, comprising control means for controlling the gate voltage control means and the potential supply means,
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When receiving the electromagnetic wave detection start signal, the gate voltage control unit and the potential are applied so that the imaging potential is supplied to the first electrode and the imaging is started by supplying an off voltage to the gates of the plurality of transistors. An electromagnetic wave information detection system for controlling the donating means. The electromagnetic wave detection means is an electromagnetic wave detection means for detecting the start and end of reception of the electromagnetic wave and transmitting an electromagnetic wave detection signal having information on the start and end of electromagnetic wave detection,
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When the electromagnetic wave detection start information is received by the electromagnetic wave detection signal, the imaging potential is supplied to the first electrode and an off voltage is supplied to the gates of the plurality of transistors to start imaging. The gate voltage control means and the gate voltage control means so as to supply a turn-on voltage to the gates of the plurality of transistors sequentially and perform a read operation when a predetermined period of time has elapsed after receiving the electromagnetic wave detection end information by the transmitted electromagnetic wave detection signal. The electromagnetic wave information detection system according to claim 1, wherein the electromagnetic wave information detection system controls the potential supply means.   The electromagnetic wave information detection system according to claim 1, wherein an active layer of the normally-on type field effect transistor is an oxide semiconductor.   The electromagnetic wave information detection system according to claim 3, wherein the oxide semiconductor is IGZO.   The photoelectric conversion layer includes a charge generation layer using an organic compound as a charge generation agent that generates positive and negative charges when irradiated with electromagnetic waves, and a charge that transports only positive charges generated in the charge generation layer. The electromagnetic wave information detection system according to claim 1, further comprising a charge transport layer using an organic compound as a transport agent. The electromagnetic wave information detection apparatus further includes a signal line connected to the plurality of normally-on field effect transistors, and a connection unit for connecting the signal line to a predetermined reference potential.
The control means supplies the potential for imaging to the first electrode in advance and sets the plurality of transistors in a standby period before setting the gate voltages of the plurality of transistors to a voltage of −0.5V to 0.5V. The gate voltage control means, the potential supply means, and the gate voltage of the transistor are set to 0 V, the predetermined reference potential is supplied to the first electrode, and the signal wiring is connected to the predetermined reference potential. 6. The electromagnetic wave information detection system according to claim 5, wherein the connection means is controlled.   The electromagnetic wave information detection apparatus further includes a plurality of storage capacitors respectively connected to the plurality of second electrodes, and stores negative charges generated in the charge generation layer in the storage capacitor when the imaging starts. The electromagnetic wave information detection system according to any one of claims 1 to 6.   The electromagnetic wave information detection system according to claim 1, further comprising a radiation conversion layer that converts radiation into the electromagnetic wave having a longer wavelength than the radiation. Electromagnetic wave detection means for detecting at least the start of reception of electromagnetic waves and transmitting an electromagnetic wave detection start signal;
A first electrode;
A plurality of second electrodes;
A photoelectric conversion layer provided between the first electrode and the plurality of second electrodes;
A plurality of normally-on field effect transistors respectively connected to the plurality of second electrodes;
Gate voltage control means for controlling gate voltages of the plurality of transistors;
A potential providing means for providing a predetermined potential to the first electrode;
A control means connected to the electromagnetic wave detection means, comprising: a control means for controlling the gate voltage control means and the potential supply means;
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When receiving the electromagnetic wave detection start signal, the gate voltage control unit and the potential are applied so that the imaging potential is supplied to the first electrode and the imaging is started by supplying an off voltage to the gates of the plurality of transistors. An electromagnetic wave information detecting device for controlling the providing means. The electromagnetic wave detection means is an electromagnetic wave detection means for detecting the start and end of reception of the electromagnetic wave and transmitting an electromagnetic wave detection signal having information on the start and end of electromagnetic wave detection,
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When the electromagnetic wave detection start information is received by the electromagnetic wave detection signal, the imaging potential is supplied to the first electrode and an off voltage is supplied to the gates of the plurality of transistors to start imaging. The gate voltage control means and the gate voltage control means so as to supply a turn-on voltage to the gates of the plurality of transistors sequentially and perform a read operation when a predetermined period of time has elapsed after receiving the electromagnetic wave detection end information by the transmitted electromagnetic wave detection signal. The electromagnetic wave information detecting apparatus according to claim 9, wherein the electromagnetic wave information detecting device controls the potential providing means.   The electromagnetic wave information detection device according to claim 9 or 10, wherein an active layer of the normally-on type field effect transistor is an oxide semiconductor.   The electromagnetic wave information detection apparatus according to claim 11, wherein the oxide semiconductor is IGZO.   The photoelectric conversion layer includes a charge generation layer using an organic compound as a charge generation agent that generates positive and negative charges when irradiated with electromagnetic waves, and a charge that transports only positive charges generated in the charge generation layer. The electromagnetic wave information detection apparatus as described in any one of Claims 9-12 provided with the electric charge transport layer which used the organic compound for the transport agent. The electromagnetic wave information detection apparatus further includes a signal line connected to the plurality of normally-on field effect transistors, and a connection unit for connecting the signal line to a predetermined reference potential.
The control means supplies the potential for imaging to the first electrode in advance and sets the plurality of transistors in a standby period before setting the gate voltages of the plurality of transistors to a voltage of −0.5V to 0.5V. The gate voltage control means, the potential supply means, and the gate voltage of the transistor are set to 0 V, the predetermined reference potential is supplied to the first electrode, and the signal wiring is connected to the predetermined reference potential. The electromagnetic wave information detection apparatus of Claim 13 which controls the said connection means.   The electromagnetic wave information detection apparatus further includes a plurality of storage capacitors respectively connected to the plurality of second electrodes, and stores negative charges generated in the charge generation layer in the storage capacitor when the imaging starts. The electromagnetic wave information detection apparatus as described in any one of Claims 9-14.   The electromagnetic wave information detection apparatus as described in any one of Claims 9-14 further provided with the radiation conversion layer which converts a radiation into the said electromagnetic wave with a wavelength longer than the said radiation. Electromagnetic wave detection means for detecting at least the start of reception of electromagnetic waves and transmitting an electromagnetic wave detection start signal;
A first electrode;
A plurality of second electrodes;
A photoelectric conversion layer provided between the first electrode and the plurality of second electrodes;
A plurality of normally-on field effect transistors respectively connected to the plurality of second electrodes;
Gate voltage control means for controlling gate voltages of the plurality of transistors;
A potential providing means for providing a predetermined potential to the first electrode;
An electromagnetic wave information detection method for detecting electromagnetic wave information using an electromagnetic wave information detection apparatus, comprising: a control means connected to an electromagnetic wave detection means, comprising a control means for controlling the gate voltage control means and the potential supply means. There,
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When receiving the electromagnetic wave detection start signal, the gate voltage control unit and the potential are applied so that the imaging potential is supplied to the first electrode and the imaging is started by supplying an off voltage to the gates of the plurality of transistors. An electromagnetic wave information detection method for controlling a donating means. The electromagnetic wave detection means is an electromagnetic wave detection means for detecting the start and end of reception of the electromagnetic wave and transmitting an electromagnetic wave detection signal having information on the start and end of electromagnetic wave detection,
The control means supplies an imaging potential to the first electrode in advance and sets the gate voltages of the plurality of transistors to a voltage of −0.5 V or more and 0.5 V or less, and is transmitted from the electromagnetic wave detection means. When the electromagnetic wave detection start information is received by the electromagnetic wave detection signal, the imaging potential is supplied to the first electrode and an off voltage is supplied to the gates of the plurality of transistors to start imaging. The gate voltage control means and the gate voltage control means so as to supply a turn-on voltage to the gates of the plurality of transistors sequentially and perform a read operation when a predetermined period of time has elapsed after receiving the electromagnetic wave detection end information by the transmitted electromagnetic wave detection signal. The electromagnetic wave information detection method according to claim 17, wherein the potential supply means is controlled.   The electromagnetic wave information detection method according to claim 17 or 18, wherein an active layer of the normally-on type field effect transistor is an oxide semiconductor.   The electromagnetic wave information detection method according to claim 19, wherein the oxide semiconductor is IGZO.   The photoelectric conversion layer includes a charge generation layer using an organic compound as a charge generation agent that generates positive and negative charges when irradiated with electromagnetic waves, and a charge that transports only positive charges generated in the charge generation layer. The electromagnetic wave information detection method according to any one of claims 17 to 20, further comprising a charge transport layer using an organic compound as a transport agent. The electromagnetic wave information detection apparatus further includes a signal line connected to the plurality of normally-on field effect transistors, and a connection unit for connecting the signal line to a predetermined reference potential.
The control means supplies the potential for imaging to the first electrode in advance and sets the plurality of transistors in a standby period before setting the gate voltages of the plurality of transistors to a voltage of −0.5V to 0.5V. The gate voltage control means, the potential supply means, and the gate voltage of the transistor are set to 0 V, the predetermined reference potential is supplied to the first electrode, and the signal wiring is connected to the predetermined reference potential. The electromagnetic wave information detection method according to claim 21, wherein the connection means is controlled.   The electromagnetic wave information detection apparatus further includes a plurality of storage capacitors respectively connected to the plurality of second electrodes, and stores negative charges generated in the charge generation layer in the storage capacitor when the imaging starts. The electromagnetic wave information detection method as described in any one of Claims 17-22.   The electromagnetic wave information detection method according to any one of claims 17 to 23, further comprising a radiation conversion layer that converts radiation into the electromagnetic wave having a longer wavelength than the radiation.

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