JP2003060178A - Radiation image detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image detector at a low cost, which is light in weight and can obtain a digital radiation image of a high image quality. SOLUTION: The radiation image detector comprises a first constituting element containing fluorescent particles for absorbing an electromagnetic wave having a shorter wavelength than that of a radioactive ray incident in response to an intensity of the incident ray to generate the electromagnetic wave, and dispersing the particles in a binder for absorbing the electromagnetic wave to generate a charge; a second constituting element for storing the charge generated in the first element; and a third constituting element for outputting a signal based on the charge stored in the second element, and formed on a fourth constituting element. The detector outputs an image signal of the incident radioactive ray based on the signal output from the third element. Here, the fourth element is constituted by using a resin. The first element is formed by dispersing the fluorescent particles in the binder of an organic photoconductor containing fullerenes or a carbon nanotube. The second element is a capacitor. The third element is formed by sing an organic semiconductor or an element of a split silicon laminated structured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of radiological image diagnosis in medicine. In particular, it relates to a radiation image detector for obtaining a radiation image used for diagnostic purposes.

[0002]

2. Description of the Related Art Conventionally, a so-called screen film system (SF system), which is a combination of a fluorescent intensifying screen and a radiographic film, has been used for forming a radiographic image as a method for obtaining a radiographic image. In this SF system, when radiation such as X-rays transmitted through a subject is incident on the fluorescent intensifying screen, the phosphor contained in the fluorescent intensifying screen absorbs the energy of the radiation and emits fluorescence. By this light emission, the radiographic films superposed so as to be in close contact with the fluorescent intensifying screen are exposed to light, and a radiographic image is formed on the radiographic film.

However, in the SF system, it is necessary to match the sensitivity regions of the radiographic film used for photographing and the fluorescent intensifying screen to perform photographing. In addition, the radiographic film must be chemically developed and fixed, and it takes time until a radiographic image is obtained. Not preferred.

Further, the SF system is an analog image, and in order to perform remote diagnosis using a digital network system, it is necessary to convert the image signal of the radiation image obtained by the SF system into a digital signal. Become.

Therefore, in the recent radiographic image capturing, instead of the SF system, a digital X-ray image diagnostic apparatus such as a computed radiography (CR) or a flat panel type radiation detector (FPD) is used.
A system for obtaining a radiographic image by extracting a digital electric signal of the radiographic image has appeared. In such a system, since a radiation film is not used unlike the SF system, there is no complicated process such as development processing, and the radiation can be quickly displayed on the screen of the image display device, for example, the screen of the cathode ray tube or the liquid crystal display panel. You can draw an image.

In the field of medical image diagnosis, a computer tomography apparatus (CT) or a nuclear magnetic resonance tomography apparatus (M) is used.
Recently, digital radiation image detecting means such as RI) have been widely used, and by placing these images on a network together with these images, remote diagnosis and the like can be easily performed.

Further, the radiation image detector used in the medical field for obtaining the image signal of the radiation image can be classified into a "stationary type" and a "cassette type". The "stationary type" is mainly used for imaging the chest and abdomen, and the radiation image detector and its peripherals are integrated, and the imaging is always installed in the imaging room. In this case, the patient must go to the radiography room himself / herself when taking a radiographic image.

On the other hand, in the case of the "cassette type", for example, in the SF system, the fluorescent intensifying screen and the radiation film are stored in a flat container called a cassette, and the radiation is taken to the bed of a serious patient who cannot move. An image is taken. That is, the moving type radiation generator and the cassette are conveyed to the bed of the patient, and the radiation image is taken while the patient is lying down. For example, in chest radiography, it is said that this cassette radiography occupies half of the whole chest X-ray radiography.

[0009]

CR, which is a digital radiation image detector, can be used as a cassette type radiation image detector like the SF system, but it is expensive and the image quality is not as good as that of the SF system. .
Further, although the FPD can obtain an image quality equal to or higher than that of the SF system, it is expensive like the CR and it is difficult to realize a lightweight cassette type radiation image detector.

Therefore, the present invention provides a radiation image detector which is inexpensive, lightweight, and capable of obtaining a high-quality digital radiation image.

[0011]

In a radiation image detector according to the present invention, a phosphor particle that generates an electromagnetic wave having a shorter wavelength than the incident radiation in accordance with the intensity of the incident radiation absorbs the electromagnetic wave. Based on the first component dispersed in the charge-generating binder, the second component storing the charge generated in the first component, and the charge stored in the second component An image of the radiation input based on the signal output from the third component, which includes a third component that outputs a signal and a fourth component that holds the first to third components In the radiation image detector that outputs a signal, the fourth component is made of resin.

In the present invention, the first to third constituent elements are formed on the fourth constituent element made of resin.
The first component is, for example, a binder, which is an organic photoconductor containing fullerene or carbon nanotubes, in which phosphor particles are dispersed, and has a wavelength longer than that of the incident radiation depending on the intensity of the incident radiation. Short electromagnetic waves are generated by the phosphor particles, and at the same time, the binder absorbs the generated electromagnetic waves to generate charges. The second component is a capacitor, and the charge generated in the first component is stored. The third component is formed using an organic semiconductor or an element having a divided silicon laminated structure, and a signal is output based on the charge stored in the second component, and the third component is formed. The image signal of the radiation image is output based on the signals output from the components.

Further, the radiation image detector has a portable structure, and a power supply means constituted by, for example, a sheet-like battery is provided, and the power supply means drives the radiation image detector. The necessary power is supplied. Further, storage means for storing the image signal is provided, and the storage means is removable.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of a system using a radiation image detector. In FIG. 1, the radiation emitted from the radiation generator 10 is applied to a radiation image detector 20 through a subject (for example, a patient in a medical facility) 15. In the radiation image detector 20,
An image signal DFE is generated based on the intensity of the applied radiation. The generated image signal DFE is read by the image processing unit 51 connected to the radiation image detector 20. Alternatively, after being stored in a portable recording medium such as a semiconductor memory card attached to the radiation image detector 20, the recording medium is removed from the radiation image detector 20 and attached to the image processing unit 51. ,
It is supplied to the image processing unit 51.

In the image processing section 51, the radiation image detector 2
Shading correction, gain correction, gradation correction, edge enhancement processing, dynamic range compression processing, etc. are performed on the image signal DFE generated by 0, and processing is performed so as to obtain an image signal suitable for diagnosis and the like. Further, the image processing unit 51 is connected to an image display unit 52 configured by using a cathode ray tube, a liquid crystal display element, a projector or the like. In the image processing unit 51, an image signal during image processing and image processing completion An image based on the subsequent image signal is displayed.

Further, the image processing section 51 enlarges and reduces the image and also performs compression and decompression processing of the image signal in order to facilitate accumulation and transfer of the image signal. Therefore, by enlarging or reducing the image displayed on the image display unit 52, it is possible to easily confirm the imaging region and perform the processing state. Further, it is possible to specify a displayed image or an area of the displayed image and automatically perform appropriate image processing on the specified image or the specified area.

The image processing unit 51 includes a keyboard,
An information input unit 53 configured by using a mouse, a pointer or the like is connected, and patient information or the like can be input by this information input unit 53 and additional information can be added to the image signal. Further, the information input unit 53 also designates image processing, saves and reads out image signals, and gives instructions when transmitting and receiving image signals via a network.

The image processing section 51 further includes an image output section 5
4, an image storage unit 55, and a computer-aided image automatic diagnosis unit (CAD) 56 are connected.

The image output section 54 displays and outputs the radiation image on a recording paper, a film or the like. For example, using a silver salt photographic film, exposure is performed based on an image signal. By developing the exposed silver salt photographic film, a radiation image is drawn and output as a silver image. When printing and outputting a radiation image on recording paper, an inkjet printer that applies pressure to the ink based on the image signal to spray the ink from the tip of the thin nozzle onto the recording paper for printing, and based on the image signal A thermal printer that melts or sublimates the ink to transfer the image to the recording paper, scans the photoconductor with laser light based on the image signal, and transfers the toner adhering to the photoconductor to the paper, then heat and pressure. The image output unit 54 is configured using a laser printer or the like that forms an image on recording paper by fixing.

The image storage unit 55 stores the image signal of the radiation image so that it can be read out as needed. The image storage unit 55 stores the image signal by using, for example, magnetically, hologram element, perforation, change in dye distribution, or the like.

The CAD 56 performs computer processing and computer analysis of the radiographic image taken and provides the doctor with information necessary for diagnosis, thereby supporting diagnosis so that no lesion is overlooked. In addition, diagnosis is automatically performed based on the results of computer processing and computer analysis.

The image signal of the radiation image is stored in the hospital facility not only through the image output unit 54, the image storage unit 55 and the CAD 56 described above, but also through a network 60 such as a so-called LAN, Internet and PACS (medical image network). It can be sent to other departments or remote areas. Also, via this network, CT61 and M
Image signal obtained from RI62 or CR or other FP
The image signal obtained from D63 and other inspection information can also be sent, and the network 60 is used for comparison with the radiation image obtained by the radiation image detector 20.
The image signal, inspection information, etc. sent via the image display unit 52 may be displayed or output from the image output unit 54. Further, the image signal, inspection information, etc. sent may be stored in the image storage unit 55. Further, the image signal of the radiation image obtained by the radiation image detector 20 or the like may be stored in the external image storage device 64, or the radiation obtained by the radiation image detector 20 may be displayed on the screen of the external image display device 65. An image is also displayed.

Next, an example of the structure of the radiation image detector 20 is shown in FIG. The radiation image detector 20 includes an image pickup panel 21, a control circuit 30 that controls the operation of the radiation image detector 20, a rewritable read-only memory (for example, a flash memory), and the like, and an image signal output from the image pickup panel 21. A memory unit 31 for storing the information, an operation unit 32 for switching the operation of the radiation image detector 20, a display unit 33 indicating that preparation for capturing a radiation image is completed and a predetermined amount of image signal is written in the memory unit 31, A power supply unit 34 that supplies electric power required to drive the image pickup panel 21 to obtain an image signal, the radiation image detector 20, and the image processing unit 5.
A communication connector 35 for performing communication between one and the other, and a housing 40 for housing these are provided. Further, the image pickup panel 21 outputs the charge generated and accumulated according to the intensity of the applied radiation from the scan drive circuit 25 which outputs a read signal for reading out for each line, or the scan drive circuit 25. It also has a signal selection circuit 27 that outputs the charges read by the read signal as an image signal. The interior of the housing 40, the scan drive circuit 25, the signal selection circuit 27, the control circuit 30, the memory unit 31, and the like are covered with a radiation shielding member (not shown), and radiation scattering occurs inside the housing 40. It is also prevented that each circuit is irradiated with radiation.

It is a preferable embodiment for the casing 40 to have an outer shape made of a material that withstands an external impact and is as light as possible, that is, aluminum or its alloy. The radiation incident surface side of the housing 40 is configured by using a non-metal that easily transmits radiation, such as carbon fiber. On the back side, which is the opposite side to the radiation incident surface, it is generated for the purpose of preventing the radiation from passing through the radiation image detector 20, or because the material forming the radiation image detector 20 absorbs the radiation. In order to prevent the influence from secondary radiation, it is a preferred embodiment to use a material that effectively absorbs radiation, such as a lead plate.

FIG. 3 shows a circuit configuration for radiation image detection. The image pickup panel 21 has a two-dimensionally arranged collection electrode 220 for accumulating and reading out charges generated according to the intensity of the irradiated radiation. And this collecting electrode 2
20 is used as one electrode of the capacitor 221, and charges are stored in the capacitor 221. Here, one collecting electrode 220 corresponds to one pixel of the radiation image.

The scanning lines 223-1 to 223-m and the signal lines 224-1 to 224-n are arranged so as to be orthogonal to each other between the pixels. The capacitor 221- (1,1) includes a transistor 222-having a silicon laminated structure or an organic semiconductor.
(1,1) is connected. This transistor 222- (1,
1) is, for example, a field effect transistor, the drain electrode or the source electrode of which is connected to the collecting electrode 220- (1,1) and the gate electrode of which is connected to the scanning line 223-1. The source electrode is connected to the signal line 224-1 when the drain electrode is connected to the collecting electrode 220- (1,1), and the drain electrode is connected to the signal line 224-1 when the source electrode is connected to the collecting electrode 220- (1,1). It is connected to the line 224-1. Further, the scanning line 223 and the signal line 224 are similarly connected to the collecting electrode 220, the capacitor 221, and the transistor 222 of other pixels.

FIG. 4 is a partial cross-sectional view of the image pickup panel 21. Particles for generating electromagnetic waves having a shorter wavelength than the incident radiation are provided on the irradiation surface side of the radiation according to the intensity of the incident radiation. A charge generation layer 211 is provided as a first component dispersed in a binder that absorbs electromagnetic waves and generates charges.

The radiation incident on the charge generation layer 211 is a so-called X-ray having a wavelength of about 1Å, and is an electromagnetic wave transmitted through the human body, ships and members of aircraft. This electromagnetic wave is generally obtained by a fixed anode or a rotating anode X-ray tube, and the load voltage of the anode is 10 kV to 300 kV. 20 kV to 15 especially when used for medical purposes
0 kV is used. This radiation is then generated by the charge generation layer 2
When the phosphor particles dispersed in No. 11 are irradiated, the wavelength becomes 3
It emits electromagnetic waves (light) of 00 nm to 800 nm.

In the charge generation layer 211, a binder is used.
As the dispersed phosphor particles, CaWO_Four, CaWO_Four:
Tungsten-based phosphors such as Pb and MgWO, Y₂
O₂S: TbXGd₂O₂S: Tb, La₂O₂S: Tb,
(Y, Gd)₂O₂S: Tb, (Y, Gd)₂O₂S: T
terbium-activated rare earth oxysulfide fluorescents such as b and Tm
Body, YPO_Four: Tb, GdPO_Four: Tb, LaPO_Four: T
b or other terbium-activated rare earth phosphate phosphor, LaO
Br: Tb, LaOBr: Tb, Tm, LaOCl: T
b, LaOCl: Tb, Tm, GdOBr: Tb, Gd
OBr: Tb, Tm, GdOCl: Tb, GdOCl:
Terbium activated rare earth oxyhalogens such as Tb and Tm
Compound phosphor, LaOBr: Tm, LaOCl: Tm
Which thulium activated rare earth oxyhalide phosphor,
Gadolini such as LaOBr: Gd, LuOCl: Gd
Mu activated rare earth oxyhalide phosphor, GdOB
r: Ce, GdOCl: Ce, (Gd, Y) OBr: C
e, (Gd, Y) OCl: Ce and other cerium-activated rare earths
Oxyhalide-based phosphor, BaSO_Four: Pb, B
aSO_Four: Eu²⁺, (Ba, Sr) SO_Four: Eu²⁺Such as
Barium Sulfate Phosphor, Ba ₃(PO_Four)₂: Eu²⁺,
(Ba₂PO_Four)₂: Eu²⁺, Sr₃(PO_Four)₂: Eu²⁺,
(Sr₂PO_Four)₂: Eu²⁺Such as divalent europium
Active alkaline earth metal phosphate-based phosphor, BaFCl: Eu
²⁺, BaFBr: Eu²⁺, BaFCl: Eu²⁺, Tb,
BaFCl: Eu²⁺, Tb, BaF₂・ BaCl₂・ KC
l: Eu²⁺, (Ba, Mg) F₂・ BaCl₂・ KCl:
Eu²⁺Divalent europium-activated alkaline earth metal such as
Fluorohalide-based phosphor, CsI: Na, CsI: T
1, NaI, KI: Tl and other iodide phosphors, Zn
S: Ag, (Zn, Cd) S: Ag, (Zn, Cd)
S: Cu, (Zn, Cd) S: Cu, Ag and other sulfides
-Based phosphor, HfP₂O₇, HfP₂O₇: Cu, Hf₃(P
O_Four)_FourHafnium phosphate phosphors such as YTaO_Four, Y
TaO_Four: Tm, YTaO_Four: Nb, (Y, Sr) TaO
_Four: Nb, LuTaO_Four, LuTaO_Four: Tm, LuTa
O_Four: Nb, (Lu, Sr) TaO_Four: Nb, GdTaO
_Four: Tm, Mg_FourTa₂O₉: Nb, Gd₂O₃・ Ta₂O _Five・
B₂O₃: Tb and other tantalate phosphors, Gd
₂O₂S: Eu³⁺, (La, Gd, Lu)₂Si₂O₇: E
u, ZnSiO_Four: Mn, Sr₂P₂O₇: For Eu, etc.
Can be Especially high X-ray absorption and luminous efficiency
Gd₂O₂Using S: Tb, CsI: Tl is
It is preferable for obtaining a high quality radiographic image. These phosphors
The average diameter of the particles is preferably 1 μm or more and 7 μm or less.
Is the diameter. The phosphor particles may be amorphous particles or spherical particles.
It can be shaped.

An organic conductor is used as the binder in the charge generation layer 211. Examples of the organic conductor include a π-conjugated polymer material and a light emitting material used for a low molecular weight organic EL element. For example, poly (2-methoxy, 5-
(2'ethylhexyloxy) -p-phenylene vinylene) and poly (3-alkyldiophen). In addition, "Organic EL materials and displays (2001 2
19th of March 28, issued by CMC Inc.)
The compounds described on pages 0 to 203 and "organic E
L element and its industrialization front line (November 30, 1998)
Compounds described on pages 81 to 90 of "NTS Co., Ltd."). Examples of the light-emitting material used for the low molecular weight organic EL device include, for example, "organic EL device and its industrial front line (published on Nov. 30, 1998, NTTS Co., Ltd.)", pages 36 to 56. And the organic EL materials and displays (February 28, 2001, CM Corporation).
See pp. 148-172. In the present invention, a particularly preferable organic compound capable of photoelectric conversion is a conductive polymer compound, and the most preferable one is a π-conjugated polymer compound. Here, FIG. 5 is a basic skeleton of the conductive polymer compound, FIGS. 6 to 8 are specific examples of the π-conjugated polymer compound, and FIG.
Shows a specific example of a conductive polymer compound other than the π-conjugated system. The conductive polymer material and the low molecular weight organic EL element are not limited to those described above.

Further, in the film of the charge generation layer 211, for example, fullerene C-60, fullerene C-70, fullerene C-76, fullerene C-78, fullerene C-8.
4, mixing fullerene C-240, fullerene C-540, mixed fullerene, fullerene nanotube, multi-walled nanotube (Multi Walled Nanotube), single-walled nanotube (Single Walled Nanotube), etc. occurs according to electromagnetic waves (light) This is a preferable mode for obtaining a high-quality radiation image, because the movement of the charge can be made favorable when the generated charge is moved by utilizing the bias voltage as described later. Further, the charge generation layer 211 preferably has a thickness of 100 to 2000 μm.

An insulating film 212 is arranged on the radiation irradiation surface side of the charge generation layer 211, and an electrode 213 is further arranged on the insulating film 212. The insulating film 212 is, for example, polyurethane, vinyl chloride copolymer, vinyl chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer, polyamide resin, polyvinyl butyral, cellulose derivative, styrene-butadiene copolymer, various synthetic rubber resins. , Phenol resin, epoxy resin, urea resin,
Examples include melanin resin, phenoxy resin, silicone resin, acrylic resin, and urea formamide resin. Among them, polyurethane, polyester, vinyl chloride copolymer, polyvinyl butyral and nitrocellulose can be used. A suitable thickness is 1 μm to 100 μm.

Examples of the electrode 213 include conductive transparent materials such as indium tin oxide (ITO), SnO ₂ and ZnO, and metals such as gold, silver, aluminum and chromium. The electrode 213 can be formed by performing vapor deposition, sputtering, or the like using these electrode substances. By applying a bias voltage between the electrode 213 thus formed and the ground, the charges generated in the film of the charge generation layer 211 can be moved. The bias voltage at this time is preferably 0.05 to 20 V / μm.
The charges moved by the bias voltage are accumulated in the second constituent element, for example, the capacitor 221 formed on the surface side of the charge generation layer 211 opposite to the radiation irradiation surface side.

The collecting electrode 220, which is one electrode of the capacitor 221, and the other electrode 221a of the capacitor 221.
Can be selected from, for example, chromium or aluminum, or a general metal electrode or a transparent electrode. However, a metal having a low work function (4.5 eV or less), an alloy, an electrically conductive compound, or a mixture thereof is used as a metal film. Preference is given to using. Specific examples of such preferable materials include sodium, sodium-potassium alloy, magnesium, lithium, aluminum, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum /
Aluminum oxide (Al ₂ 0 ₃₎ mixture, indium, a lithium / aluminum mixture, and either a rare earth metal such as. The electrodes 220 and 221a can be manufactured by forming thin films of these conductive materials by a method such as vapor deposition or sputtering. Further, the sheet resistance is preferably several hundreds Ω / □ or less, and the film thickness is usually 10 nm to
It is selected in the range of 1 μm, preferably 50 to 200 nm. This is because if the film thickness is thin, the conductive material becomes island-shaped, and if the film thickness is thick, it takes time to form the film. In addition, as the dielectric material interposed between the electrode 220 and the electrode 221a, an insulating layer used in a third component described later is used. The capacity of this capacitor 221 is preferably 0.1 to 1 pF.

A transistor 222 such as a TFT (thin film transistor), which is a switching element, is provided as a third constituent element for outputting a signal based on the charges accumulated in the capacitor 221 on the surface of the capacitor 221 opposite to the radiation irradiation side. ) Is formed. This TFT may be an inorganic semiconductor type used in a liquid crystal display or the like, or an organic semiconductor type, and is preferably a TFT formed on a plastic film. Amorphous silicon-based TFTs are known as TFTs formed on plastic films.
FSA (Fluidic Self Ass
embly) technology, that is, minute C made of single crystal silicon
By arranging MOS (Nanoblocks) on an embossed plastic film, the TFT may be formed on the flexible plastic film. Furthermore, Science 283,822 (1999) and Appl.Phys.Lett, 7
It may be a TFT using an organic semiconductor as described in documents such as 71488 (1998), Nature, 403, 521 (2000).

As described above, as the switching element used in the present invention, the TFT manufactured by the FSA technique and the TFT using the organic semiconductor are preferable, and the particularly preferable one is the TFT using the organic semiconductor. If a TFT is formed using this organic semiconductor, TF is formed using silicon.
Equipment such as a vacuum deposition device is not required as in the case of configuring T, and TF can be used by utilizing printing technology and inkjet technology.
Since T can be formed, the manufacturing cost is low. Furthermore, since the processing temperature can be lowered, it can be formed into a plastic substrate shape which is weak against heat.

Of the TFTs using the organic semiconductor, the field effect transistor (FET) is particularly preferable, and specifically, the organic TFT having the structure shown in FIGS. 5A to 5C is preferable. The organic TFT shown in FIG. 5A has a gate electrode on a substrate,
A gate insulating layer, a source / drain electrode, and an organic semiconductor layer are sequentially formed. The organic TFT shown in FIG. 5B is
A gate electrode, a gate insulating layer, an organic semiconductor layer, and a source / drain electrode are sequentially formed on a substrate.
The organic TFT shown in (1) is one in which a source / drain electrode, a gate insulating layer, and a gate electrode are sequentially formed on an organic semiconductor single crystal.

Here, the compound forming the organic semiconductor layer 222a of the transistor 222 shown in FIG. 4 may be a single crystal material or an amorphous material, and a so-called organic EL element structure can also be applied. The constituent material of the organic EL element may be low molecular weight or high molecular weight (also called light emitting polymer). The material used in the organic conductor of the present invention is a conductive polymer material (π
Examples thereof include conjugated polymer materials and silicon polymer materials) and light-emitting materials used for low molecular organic EL devices. For example, as the conductive polymer material, poly (2-methoxy, 5- (2'ethylhexyloxy) -p-phenylene vinylene) and poly (3-alkylthiophene),
and so on. In addition, "Organic EL materials and displays (20
Compounds described on pages 190 to 203 of February 28, 2001 (CMC Inc.),
Pages 81-9 of "Organic EL device and its frontier of industrialization" (published on November 30, 1998 by NTS Co., Ltd.)
Examples thereof include the compounds described on page 9. Examples of the light emitting material used for the low molecular weight organic EL device include, for example, "Organic EL device and its industrial front line (published on Nov. 30, 1998, NTS Co., Ltd.)", pages 36 to 56. The compounds listed on the page, "Organic EL materials and displays (February 28, 2001 C.
Published by M.C.) ", pages 148 to 172, and the like. In the present invention, particularly preferable organic semiconductors are single crystals of condensed aromatic hydrocarbon compounds represented by pentacene, triphenylene, anthracene, etc., and conductive polymer compounds.
Examples thereof include conjugated polymer compounds. 6 shows a basic skeleton of a conductive polymer compound, FIGS. 7 to 9 show specific examples of π-conjugated polymer compounds, and FIG. 10 shows specific examples of conductive polymer compounds other than π-conjugated system compounds. The conductive polymer material and the low molecular weight organic EL element are not limited to those described above.

In addition, in an organic semiconductor using a π-conjugated polymer compound, a three-dimensional π-electron such as fullerene or carbon nanotube is used for the purpose of carrier transfer and carrier trap between a plurality of π-conjugated polymer compounds. It is preferable to add a compound having a cloud.

These compounds are, for example, fullerene C-
60, fullerene C-70, fullerene C-76, fullerene C-78, fullerene C-84, fullerene C-
240, fullerene C-540, mixed fullerene, fullerene nanotube, multi-walled nanotube (Mult
i Walled Nanotube, Single Wall
ed Nanotube). Further, a fullerene or carbon nanotube may have a substituent introduced for the purpose of imparting compatibility with a solvent.

Further, in the transistor 222, as shown in FIG. 4, the conduction layer 22 which is a layer for selectively conducting holes.
2b may be formed between the organic semiconductor layer 222a and the drain electrode (source electrode) 222c, or between the organic semiconductor layer 222a and the source electrode (drain electrode) 222d.

The conductive layer 222b is a material in which an additive is added to a conductive polymer material or a light emitting material used for a low molecular weight organic EL device in order to improve conversion efficiency and carrier transfer efficiency to an electrode. Are formed by using. As the additive, a hole injecting material, a hole transporting material, an electron transporting material, an electron injecting material or the like used in an organic EL element can be applied. Specific examples thereof include, for example, triazole derivatives, oxadiazole derivatives, imidazole derivatives,
Polyarylalkane derivative, pyrazoline derivative and pyrazolone derivative, phenylenediamine derivative, arylamine derivative, amino-substituted chalcone derivative, oxazole derivative, styrylanthracene derivative, fluorenone derivative, hydrazone derivative, stilbene derivative, silazane derivative, aniline copolymer, and also , Conductive polymer oligomers, especially thiophene oligomers, porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, heterocyclic tetracarboxylic acids such as naphthalene perylene Anhydride, carbodiimide, fluorenylidene methane derivative, anthraquinodimethane and anthrone derivative, oxadiazole derivative, thiadiazole Conductor, quinoxaline derivatives, 8-
A metal complex of a quinolinol derivative (for example, tris (8-quinolinolato) aluminum (Alq3), tris (5,7-dichloro-8-quinolinatolate) aluminum, tris (5,7-dibromo-8-quinolinato) aluminum, tris (2- Methyl-8-quinolylate)
Aluminum, tris (5-methyl-8-quinolinate) aluminum, bis (8-quinolinate) zinc (Z
nq2) etc.).

Drain electrode (source electrode) 222c, source electrode (drain electrode) 222d and gate electrode 22
2e may be a metal, a conductive inorganic compound, or a conductive organic compound, but is preferably a conductive organic compound from the viewpoint of ease of production, and a representative example thereof is the π-conjugated polymer compound. Is doped with Lewis acid (iron chloride, aluminum chloride, antimony bromide, etc.), halogen (iodine, bromine, etc.), sulfonate (polystyrenesulfonic acid sodium salt (PSS), potassium p-toluenesulfonate, etc.) Examples thereof include a conductive polymer obtained by adding PSS to PEDOT. Further, as the insulating layer 222f,
The insulating materials mentioned above can be used. Note that FIG. 11 shows a specific example of the organic TFT in the case where the conductive layer 222b is not provided.

Transistor 22 which is a switching element
2 includes a capacitor 221 as shown in FIGS.
A collecting electrode 220, which is one of the electrodes, is connected,
The charges accumulated in the capacitor 221 are read by driving the transistor 222. That is, by driving the switching element, a radiation image can be generated as a signal for each pixel.

The third component for outputting a signal based on the electric charge accumulated in the capacitor 221 is not limited to the one using the switching element, and for example, a signal corresponding to the amount of electric charge accumulated in the capacitor 221 is used. May be generated and output.

The substrate 214 as the fourth component holding the first to third components is preferably a plastic film. Examples of the plastic film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), cellulose. Examples thereof include films made of triacetate (TAC), cellulose acetate propionate (CAP) and the like. As described above, by using the plastic film as the substrate 214, the weight can be reduced as compared with the case where the glass substrate is used, and the resistance to impact can be improved.

Further, in these plastic films,
A plasticizer such as trioctyl phosphate or dibutyl phthalate may be added, or a known benzotriazole-based or benzophenone-based ultraviolet absorber may be added.
In addition, a resin produced by applying a so-called organic-inorganic polymer hybrid method, in which a raw material of an inorganic polymer such as tetraethoxysilane is added, and a high molecular weight is obtained by applying energy such as a chemical catalyst, heat, or light. It can also be used as a raw material.

Further, on the side of the substrate 214 opposite to the side where the transistor 222 is formed, the power source section 34 such as a manganese battery,
A primary battery such as a nickel-cadmium battery, a mercury battery, or a lead battery, or a rechargeable secondary battery may be provided. As a form of this battery, a flat form is preferable so that the radiation image detector can be thinned.

In the image pickup panel 21, the signal line 224
-1 to 224-n are provided with initialization transistors 232-1 to 232-n to which drain electrodes are connected, for example. The source electrodes of the transistors 232-1 to 232-n are grounded. In addition, the gate electrode is the reset line 23.
Connected with 1.

Scan lines 223-1 to 223 of the image pickup panel 21
-m and the reset line 231 are connected to the scan drive circuit 25 as shown in FIG. From the scan driving circuit 25, one of the scan lines 223-1 to 223-m scan line 223-p (p is 1
To a value m), the read signal RS is supplied,
Transistor 222-connected to this scan line 223-p
(p, 1) to 222- (p, n) are turned on, and the charges accumulated in the capacitors 221- (p, 1) to 221- (p, n) are transferred to the signal lines 224-1 to 224-2. It is read to n respectively. Signal line 2
24-1 to 224-n are signal converters 2 of the signal selection circuit 27.
71-1 to 271-n are connected to the signal converter 271.
-1 to 271-n generate voltage signals SV-1 to SV-n proportional to the amount of charges read on the signal lines 224-1 to 224-n. The voltage signals SV-1 to SV-n output from the signal converters 271-1 to 271-n are supplied to the register 272.

In the register 272, the supplied voltage signals are sequentially selected, and the A / D converter 273 (for example, 1
It is a digital image signal for one scan line (2 to 14 bits), and the control circuit 30 controls the scan line 2
A read signal RS is supplied to each of 23-1 to 223-m through the scan drive circuit 25 to perform image scanning, and a digital image signal for each scanning line is taken in to generate an image signal of a radiation image. This image signal is supplied to the control circuit 30. It should be noted that the scan drive circuit 25 supplies the reset signal RT to the reset line 231 to supply the transistors 232-1 to 232-1.
2-n is turned on, and scanning lines 223-1 to 22-2
The read signal RS is supplied to 3-m to supply the transistor 222- (1,
1) to 222- (m, n) is turned on, the capacitor 22
The charges accumulated in 1- (1,1) to 221- (m, n) are discharged through the transistors 232-1 to 232-n, and the image pickup panel 2
Initialization of 1 can be performed.

The control circuit 30 includes a memory section 31 and an operating section 3.
2 are connected, and the operation of the radiation image detector 20 is controlled based on the operation signal PS from the operation unit 32. The operation unit 32 is provided with a plurality of switches, and the operation unit 3
Based on the operation signal PS from 2 according to the switch operation,
Initialization of the imaging panel 21 and generation of an image signal of a radiation image are performed. Further, the image signal of the radiation image may be generated when the radiation irradiation end signal is supplied from the radiation generator 10 through the connector 35.
Further, it also performs processing such as storing the generated image signal in the memory unit 31.

Here, as shown in FIG. 2, the radiation image detector 20 is provided with a power source section 34 and a memory section 31 for storing the image signal of the radiation image, and the radiation image detector 20 is connected via a connector 35. If it is detachable, a system capable of carrying the radiation image detector 20 can be constructed. Furthermore, if the memory unit 31 is configured to be removable using a non-volatile memory, the memory unit 31 can be connected to the image processing unit 5 without connecting the radiation image detector 20 and the image processing unit 51.
Since the image signal can be supplied to the image processing unit 51 only by mounting it on No. 1, the radiation image capturing and image processing can be further facilitated and the operability can be improved. When the radiation image detector 20 is used as a stationary type, the connector 35
It is needless to say that the image signal of the radiation image can be obtained without providing the memory unit 31 and the power supply unit 34 by supplying power and reading the image signal via the.

As described above, in the above embodiment, the fourth
Since the constituent elements of (1) are made of resin, the weight can be reduced as compared with the conventional radiation image detector using the glass substrate. Further, since the fourth constituent element is made of resin, the third constituent element formed on the fourth constituent element is formed of an element having a divided silicon laminated structure or is formed of an organic semiconductor. Therefore, unlike a conventional radiographic image detector using a glass substrate, it is not necessary to use an expensive and special manufacturing apparatus for forming a thin film transistor mainly composed of silicon on a glass substrate. It can be manufactured at low cost.

[0055]

According to the present invention, phosphor particles that generate an electromagnetic wave having a shorter wavelength than the incident radiation depending on the intensity of the incident radiation are dispersed in a binder that absorbs the electromagnetic wave and generates an electric charge. The first component,
A fourth constituent element that holds a second constituent element that accumulates the electric charge generated in the first constituent element and a third constituent element that outputs a signal based on the electric charge accumulated in the second constituent element. Are formed using a resin. Therefore, it is possible to reduce the weight of the radiation image detector that generates the image signal based on the incident radiation.

Further, since the first component is formed by dispersing phosphor particles in a binder which is an organic photoconductor containing fullerene or carbon nanotubes, a high quality radiation image can be obtained. Furthermore, since the third layer is formed using an organic semiconductor or an element having a divided silicon laminated structure, the radiation image detector can be manufactured at low cost.

Further, since the first to fourth constituent elements, the power supply means and the storage means are integrated into a portable structure, it is possible to easily take a radiation image. Further, since a power supply means for supplying power to generate an image signal based on the incident radiation and a storage means for storing the image signal are provided, it is connected to a peripheral device for reading the image signal or performing signal processing. Even if it does not exist, the image signal of the radiographic image can be obtained. Further, since the storage means is removable, the image signal can be easily and easily supplied to the peripheral device.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a system using a radiation image detector.

FIG. 2 is a diagram showing an example of a structure of a radiation image detector.

FIG. 3 is a diagram showing a circuit configuration of a radiation image detector.

FIG. 4 is a partial cross-sectional view of an image pickup panel.

FIG. 5 is a diagram showing a structure of an organic TFT.

FIG. 6 is a view showing a basic skeleton of a conductive polymer compound.

FIG. 7 is a diagram showing a specific example (1) of a π-conjugated polymer compound.

FIG. 8 is a diagram showing a specific example (No. 2) of the π-conjugated polymer compound.

FIG. 9 is a diagram showing a specific example (part 3) of a π-conjugated polymer compound.

FIG. 10 is a diagram showing a specific example of a conductive polymer compound other than a π-conjugated system.

FIG. 11 is a diagram showing a specific example of an organic TFT.

[Explanation of symbols]

10 Radiation generator 20 Radiation image detector 21 Imaging panel 25 Scan drive circuit 27 Signal selection circuit 30 control circuit 31 memory 32 Operation part 33 Display 34 Power Supply 35 connector 40 cases 51 Image processing unit 52 Image display section 53 Information input section 54 Image output section 55 Image storage 211 Charge generation layer 214 substrate 220 collecting electrode 221 capacitor 222,232 transistors 223 scan lines 224 signal line 231 reset line 271 Signal converter 272 register 273 A / D converter

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // H01L 51/00 H01L 29/28 (72) Inventor Hiroshi Kita No. 1 Sakura-cho, Hino-shi, Tokyo Konica Stock In-company (72) Inventor Kazuo Genda 1 Sakura-cho, Hino-shi, Tokyo Konica stock In-company F-term (reference) 2G088 EE01 FF02 GG10 GG19 GG21 JJ05 4M118 AA10 AB01 BA14 CA11 CA15 CB11 CB20 FB13 FB20 GA10 5C024 AX24 5F14 EX88 EX22 AA20 BB03 BB07 HA15 KA10 LA08

Claims (9)

[Claims] 1. A first structure in which phosphor particles that generate an electromagnetic wave having a shorter wavelength than the incident radiation depending on the intensity of the incident radiation are dispersed in a binder that absorbs the electromagnetic wave and generates an electric charge. An element, a second constituent element that accumulates the electric charge generated in the first constituent element, and a third constituent element that outputs a signal based on the electric charge accumulated in the second constituent element, A radiation image detector that includes a fourth component that holds the first to third components, and that outputs an image signal of the input radiation based on a signal that is output from the third component, A radiation image detector, wherein the fourth component is formed of resin. 2. The radiation image detector according to claim 1, wherein in the first component, the binder is an organic photoconductor containing fullerene or carbon nanotubes. 3. The radiation image detector according to claim 1, wherein the second component is a capacitor. 4. The radiation image detector according to claim 1, wherein the third constituent element is formed by using an organic semiconductor. 5. The radiation image detector according to claim 1, wherein the third component is formed by using an element having a divided silicon laminated structure. 6. The radiation image detector according to claim 1, wherein the radiation image detector has a portable structure. 7. The radiation image detector according to claim 1, further comprising power supply means for supplying power required to drive the radiation image detector. 8. The radiation image detector according to claim 1, further comprising storage means for storing the image signal. 9. The radiation image detector according to claim 8, wherein the storage unit is removable.