WO2013057941A1 - Two-dimensional image detector - Google Patents

Two-dimensional image detector Download PDF

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Publication number
WO2013057941A1
WO2013057941A1 PCT/JP2012/006641 JP2012006641W WO2013057941A1 WO 2013057941 A1 WO2013057941 A1 WO 2013057941A1 JP 2012006641 W JP2012006641 W JP 2012006641W WO 2013057941 A1 WO2013057941 A1 WO 2013057941A1
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Prior art keywords
charge
charge storage
information
dimensional image
switch
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PCT/JP2012/006641
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French (fr)
Japanese (ja)
Inventor
吉牟田　利典
敏 徳田
弘之 岸原
正知 貝野
聖菜 吉松
貴弘 土岐
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株式会社島津製作所
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Publication of WO2013057941A1 publication Critical patent/WO2013057941A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/24—Measuring radiation intensity with semiconductor detectors
    • G01T1/247—Detector read-out circuitry
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/42—Arrangements for detecting radiation specially adapted for radiation diagnosis
    • A61B6/4208—Arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a particular type of detector
    • A61B6/4233—Arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a particular type of detector using matrix detectors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T7/00—Details of radiation-measuring instruments
    • G01T7/005—Details of radiation-measuring instruments calibration techniques
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14609—Pixel-elements with integrated switching, control, storage or amplification elements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/60—Noise processing, e.g. detecting, correcting, reducing or removing noise
    • H04N25/68—Noise processing, e.g. detecting, correcting, reducing or removing noise applied to defects
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/30—Transforming light or analogous information into electric information
    • H04N5/32—Transforming X-rays

Definitions

  • the present invention relates to a two-dimensional image detector that detects an image by radiation such as X-rays, electromagnetic waves such as visible light and infrared rays.
  • the semiconductor layer converts electromagnetic wave information into charge information.
  • the active matrix substrate includes a plurality of charge storage capacitors for storing charge information generated in the semiconductor layer, a read switch for reading the charge information of each charge storage information via the data line, the semiconductor layer, and each charge storage capacitor And a switch for switching between a conductive state and a non-conductive state.
  • the switch When the above apparatus performs the slot scan method in which irradiation and reading of radiation are alternately performed, the switch is turned on during irradiation, and the switch is turned off during reading without irradiation. As a result, it is possible to suppress degradation in image quality due to scattered rays from the subject.
  • the conventional example having such a configuration has the following problems. That is, the conventional device is line-driven in which a data line for reading out each charge accumulation information is common to each pixel. Therefore, in any of the pixels connected to the same data line, if the charge storage capacity stores excessive charge, the charge of other pixels connected to the same data line is caused by the charge overflowing from the capacity. May be adversely affected. As a cause of excessive charge, there is a leakage current due to crystal defects in the semiconductor layer. When adversely affected, there is a problem that even if the pixel is normal, the pixel value sticks to the upper limit value, and normal pixel information cannot be obtained from pixels on the same data line.
  • An object of the present invention is to provide a two-dimensional image detector capable of
  • the present invention has the following configuration. That is, the present invention provides a semiconductor layer for converting electromagnetic wave information into charge information, a plurality of charge storage capacitors for storing charge information converted by the semiconductor layer, and a charge of each charge storage capacitor through a data line.
  • a two-dimensional image detector comprising an active matrix substrate having a readout switch for reading out information
  • the two-dimensional image detector is arranged between the semiconductor layer and each of the charge storage capacitors, and switches between a conduction state and a non-conduction state for each pixel.
  • the control means operates the charge accumulation means and the switch drive means to accumulate charges in a plurality of charge accumulation capacitors, and the charge information of all the charge accumulation capacitors is abnormal pixel information. Read as. If the charge storage capacity is greater than or equal to a predetermined value, it is determined that the pixel is an abnormal pixel, and the switch of the charge storage capacity is turned off by operating the switch driving means. Accordingly, since the abnormal pixel is electrically disconnected, the charge information of other normal pixels connected to the same data line can be correctly extracted.
  • the charge accumulating means applies a bias voltage, which is lower than a bias voltage when photographing by irradiating electromagnetic waves, to the semiconductor layer.
  • the charge accumulating unit applies a bias voltage for photographing to the semiconductor layer and irradiates an electromagnetic wave.
  • the control means stores all the charges by setting all the switches of the plurality of charge storage capacitors to a conductive state, reads out the charge information of the plurality of charge storage capacitors, and as a result, detects abnormal pixels. It is preferable that the charge storage capacitor switch corresponding to the center of the region including the non-conductive state is made non-conductive to store the charge, read the charge information, and repeat this to acquire the abnormal pixel information.
  • control means causes only one charge storage capacitor switch of the plurality of charge storage capacitors to be in a conductive state and other charge storage capacitor switches to be in a non-conductive state to store charges. , Reading out the charge information of the one charge storage capacitor, and sequentially reading out the charge information of all the charge storage capacitors by setting the switches one by one for the remaining charge storage capacitors to obtain the abnormal pixel information. preferable.
  • abnormal pixel information is acquired with all the charge storage capacitor switches turned on, other normal pixels of the same data line may be erroneously determined as abnormal pixels due to the influence of the abnormal pixels. Can occur. Therefore, among the plurality of charge storage capacitors, only one charge storage capacitor switch is turned on and the other charge storage capacitor switches are turned off to store charges, and the charge information of one charge storage capacitor is stored. Read, sequentially, the charge information of all the charge storage capacitors is read by turning on the switches one by one for the remaining charge storage capacitors. By detecting abnormal pixels one by one in this way, abnormal pixel information can be obtained accurately, although detection takes time.
  • the control means turns on only one charge storage capacitor switch in each data line among the plurality of charge storage capacitors and makes another charge storage in the same data line. Charges are stored by setting the capacitance switch to the non-conductive state, the charge information of one charge storage capacitor is read out in the data line, and the switches are sequentially turned on one by one for the remaining charge storage capacitors in the data line. It is preferable to read out the charge information of all the charge storage capacitors and acquire the abnormal pixel information.
  • the storage unit stores the abnormal pixel information.
  • the control unit stores the acquired abnormal pixel information in the storage unit, and based on the abnormal pixel information stored in the storage unit, the storage unit stores the abnormal pixel information. It is preferable to operate the switch driving means.
  • control means can appropriately operate the switch drive means by referring to the storage means.
  • control means periodically acquires the abnormal pixel information.
  • the switch By acquiring abnormal pixel information periodically, even if the characteristics of the semiconductor layer change over time, the switch can be appropriately operated based on the latest abnormal pixel information.
  • the control means operates the charge storage means and the switch drive means to store charges in the plurality of charge storage capacitors, and abnormally stores the charge information of all the charge storage capacitors. Read out as pixel information. If the charge storage capacity is greater than or equal to a predetermined value, it is determined that the pixel is an abnormal pixel, and the switch of the charge storage capacity is turned off by operating the switch driving means. Accordingly, since the abnormal pixel is electrically disconnected, the charge information of other normal pixels connected to the same data line can be correctly extracted.
  • FIG. 1 is a block diagram illustrating a schematic configuration of an X-ray imaging apparatus including a two-dimensional image detector according to an embodiment.
  • the top plate 1 is made of a member that transmits X-rays, and a subject M to be examined is placed thereon.
  • An X-ray tube 3 is disposed above the top plate 1.
  • a flat panel detector 5 is disposed on the opposite side of the X-ray tube 3 across the top plate 1.
  • the flat panel detector 5 described above corresponds to the “two-dimensional image detector” in the present invention.
  • the imaging control unit 7 controls an irradiation control unit 9 that controls X-ray irradiation from the X-ray tube 3.
  • the irradiation control unit 9 is controlled by a command signal output from the imaging control unit 7 in response to an instruction from the keyboard 11 or mouse 13 operated by the photographer.
  • Information such as the X-ray irradiation intensity and irradiation time of the X-ray tube 3 is instructed from the keyboard 11 and the mouse 13.
  • Signals corresponding to transmitted X-rays detected by the flat panel detector 5 are collected by the signal collecting unit 15.
  • the collected signal is processed in the data processing unit 17 and an X-ray image is displayed on the monitor 19.
  • the flat panel detector 5 is connected to a bias applying unit 21 for applying a bias voltage to an electrode layer 33 described later.
  • the bias application unit 21 is controlled by the imaging control unit 7.
  • the bias applying unit 21 and the X-ray tube 3 correspond to the “charge storage unit” in the present invention.
  • FIGS. 2 is a diagram showing the connection relationship between the active matrix substrate and the external circuit
  • FIG. 3 is a longitudinal sectional view schematically showing the two-dimensional image detector.
  • the detection elements DU are arranged in a two-dimensional matrix, and a pattern is formed on an insulating substrate 25 such as glass.
  • the active matrix substrate 23 includes a carrier collection electrode 27, a capacitor Ca corresponding to “charge storage capacity”, and a thin film transistor Tr.
  • the carrier collection electrode 27 collects charge information converted by the semiconductor layer 29.
  • the capacitor Ca stores the charge information collected by the carrier collection electrode 27.
  • the thin film transistor Tr corresponding to the “read switch” in the present invention is a switching element that is turned on and off by an external signal and reads the charge information stored in the capacitor Ca.
  • a switch 31 is provided between the semiconductor layer 29 and the carrier collecting electrode 27 and the capacitor Ca.
  • One detection element DU corresponding to a “pixel” in the present invention includes a carrier collection electrode 27, a capacitor Ca, a switch 31, a thin film transistor Tr, and a semiconductor layer 29 and an electrode layer 33 in regions corresponding to these. Has been.
  • a bias voltage Va is applied to the electrode layer 33 by the bias applying unit 21.
  • the two-dimensional matrix of the active matrix substrate 23 is composed of, for example, 1536 ⁇ 1536 detection elements DU, but is simplified to 3 ⁇ 3 for easy understanding of the description.
  • the switch 31 is preferably a normally closed type.
  • the switch 31 is turned off for a detection element DU having an abnormality, but the number of detection elements DU is generally smaller than that of a normal detection element DU. Therefore, the drive power for turning off can be reduced by using the normally closed switch 31.
  • the above-described semiconductor layer 29 has, for example, a high dark resistance, a good photoconductive property against X-ray irradiation, and an amorphous selenium (amorphous selenium (a-Se) that can be formed into a large area by vapor deposition. )).
  • the semiconductor layer 29 is formed with a thickness of 300 to 1200 ⁇ m by, for example, vacuum deposition.
  • the semiconductor layer 29 a material that has a crystal structure such as CdZnTe and generates more charge can be used.
  • CdZnTe is used for the semiconductor layer 29, it is preferably formed by a sublimation method.
  • a film containing Zn having a thickness of 100 to 600 ⁇ m containing several to several tens mol% by the proximity sublimation method.
  • the active matrix substrate 23 includes gate lines G1 to G3 and data lines D1 to D3.
  • the gate lines G1 to G3 are electrically connected to the gate of the thin film transistor Tr for each row of the detection elements DU.
  • the data lines D1 to D3 are electrically connected to the reading side of the thin film transistor Tr for each column of the detection elements DU.
  • the active matrix substrate 23 includes switch lines SL1 to SL3 for each detection element DU.
  • the switch lines SL1 to SL3 are for individually switching between the conductive state and the nonconductive state of the switch 31 of all the detection elements DU.
  • switch lines SL1 to SL3 are drawn for each row for the sake of illustration, but the switches 31 of each detection element DU can be individually switched between a conductive state and a non-conductive state.
  • the gate lines G1 to G3, the data lines D1 to D3, and the switch lines SL1 to SL3 are referred to as the gate line G, the data line D, and the switch line SL unless particularly distinguished.
  • the gate lines G1 to G3 are connected to the gate drive unit 35. Further, the data lines D 1 to D 3 are connected to the data reading unit 37.
  • the data reading unit 37 includes a charge / voltage conversion amplifier, a multiplexer, and an A / D converter.
  • the switch lines SL1 to SL3 are connected to the switch drive unit 39.
  • the gate driver 35 applies a voltage to the gate lines G1 to G3 to turn on the thin film transistor Tr and output the charge information stored in the capacitor Ca from the data line D to the data reading unit 37.
  • the data reading unit 37 converts the received charge information into a voltage signal, converts the plurality of voltage signals into one voltage signal, converts the voltage signal into a digital signal, and outputs the digital signal. All the charge information converted in this way is collected by the signal collecting unit 15.
  • the switch drive unit 39 switches the switch 31 of any detection element DU between the conductive state and the non-conductive state according to an instruction from an abnormal pixel determination unit 43 described later.
  • the switch drive unit 39 corresponds to the “switch drive means” in the present invention.
  • FIG. 4 is a block diagram illustrating a main part of the imaging control unit.
  • the imaging control unit 7 controls the irradiation control unit 9 and the bias application unit 21 as described above, and also performs the following control.
  • the imaging control unit 7 includes an abnormal pixel information memory 41 and an abnormal pixel determination unit 43.
  • the abnormal pixel memory 41 stores abnormal pixel information obtained by the abnormal pixel information acquisition process under the control of the imaging control unit 7.
  • the abnormal pixel determination unit 43 accesses the abnormal pixel information memory 41, compares the charge information of each detection element DU in the abnormal pixel information with a predetermined value, and determines which detection element DU is abnormal. Determine if there is. Then, the abnormal pixel determination unit 43 sets the switch 31 of the detection element DU that has been determined to be abnormal by operating the switch driving unit 39 to a non-conductive state.
  • photographing control unit 7 corresponds to the “control unit” in the present invention.
  • FIG. 5 is a flowchart showing a procedure for acquiring abnormal pixel information.
  • the acquisition of abnormal pixel information is a process performed before the subject M is imaged by the X-ray imaging apparatus.
  • it is more preferably performed at every photographing, at the start-up of the apparatus, or periodically. Accordingly, the switch 31 can be appropriately operated regardless of a change in the semiconductor layer 29 with time, and a captured image free from artifacts due to abnormal pixels can be obtained over a long period of time.
  • Step S1 The imaging control unit 7 applies a bias voltage Va to the flat panel detector 5.
  • the bias voltage Va at this time may be lower than the bias voltage Va at the time of imaging by X-ray irradiation because there is no need to accelerate the charge generated in the semiconductor layer 29.
  • a lower bias voltage Va for example, 0.1 V / ⁇ m
  • Step S2 Abnormal pixel information is acquired.
  • the imaging control unit 7 collects the charge information of each detection element DU from the flat panel detector 5. Specifically, the gate lines G1 to G3 are sequentially turned on, and charge information is collected from all the detection elements DU via the data reading unit 37. The charge information obtained from all the detection elements DU is stored in the abnormal pixel information memory 41 as abnormal pixel information.
  • Step S3 An abnormal pixel is determined based on the abnormal pixel information.
  • the abnormal pixel determination unit 43 refers to the abnormal pixel information in the abnormal pixel information memory 41 to determine which detection element DU is abnormal. Specifically, for example, when the value exceeds 10% with reference to the maximum output value (maximum charge information) at the detection element DU during X-ray imaging, the detection element DU is abnormal. Judge. It is possible for the normal detection element DU to generate 10% of charge information with respect to the maximum output value even though the bias voltage Va is low and X-ray irradiation is not performed. Because there is no. Since the bias voltage Va is low and the charge information is small, the probability that an abnormal detection element DU adversely affects other detection elements DU of the same data line D is sufficiently low.
  • the probability that another detection element DU is erroneously determined to be abnormal due to an adverse effect of the abnormal detection element DU is sufficiently low.
  • the detection element DU depending on a defect or the like of the detection element DU, there may be a situation in which it is erroneously determined that another detection element DU on the same data line D is abnormal in acquiring abnormal pixel information. A technique for avoiding this will be described later in a modification.
  • Step S4 The abnormal pixel switch 31 is turned off.
  • the abnormal pixel determination unit 43 operates the switch drive unit 39 of the flat panel detector 5 based on the determination result. Specifically, the switches 31 of all the detection elements DU that are determined to be abnormal pixels are set to be in a non-conductive state. Thereby, the detection element DU which is an abnormal pixel is electrically separated.
  • the imaging control unit 7 After acquiring abnormal pixel information as described above and separating abnormal pixels, the imaging control unit 7 performs X-ray imaging by irradiating the subject M with X-rays.
  • the imaging control unit 7 operates the bias applying unit 21 and the switch driving unit 39 to accumulate charges in the capacitors Ca of the plurality of detection elements DU, and stores the charge information of all the capacitors Ca as abnormal pixels. Read as information. If the pixel information of the capacitor Ca is greater than or equal to a predetermined value, it is determined that the pixel is an abnormal pixel, and the switch 31 of the capacitor Ca is operated to operate in a non-conductive state. Therefore, since the abnormal pixel is electrically disconnected, the charge information of other normal detection elements DU connected to the same data line D can be correctly extracted. As a result, it is possible to obtain a high-quality image without accumulating excessive charges during X-ray imaging and without adversely affecting other normal detection elements DU of the same data line D during reading.
  • the abnormal pixel information can be made accurate in a relatively short time.
  • Modification 2 Of all the detection elements DU, only the switch 31 of one detection element DU is turned on, and the switches 31 of other detection elements DU are turned off to accumulate charges, and the charge information of that one detection element DU is stored. read out. Then, the switch 31 is turned on one by one for the remaining detection elements DU, and the charge information of all the detection elements DU is read out. Thereby, abnormal pixel information is acquired.
  • the abnormal pixel information can be accurately acquired although it takes time to detect.
  • Mode 3 Among all the detection elements DU, only the switch 31 of one detection element DU in each data line D is made conductive, and the switch 31 of the other detection element DU is made non-conductive in the same data line D. And the charge information of one detection element DU in the data line D is read out. Then, the switch 31 is sequentially turned on one by one for the remaining detection elements DU in the data line D, and the charge information of all the detection elements DU is read to acquire abnormal pixel information.
  • the present invention is not limited to the above embodiment, and can be modified as follows.
  • the bias voltage Va at the time of X-ray imaging may be applied, and X-rays may be irradiated from the X-ray tube 3 to acquire abnormal pixel information.
  • a detection element DU having a defect in which a leakage current increases only at the time of X-ray irradiation can be detected as an abnormal pixel.
  • the abnormal pixel information memory 41 is provided, and abnormal pixel information is stored therein.
  • the abnormal pixel information memory 41 is not necessarily provided. In that case, while reading abnormal pixel information from the data reading unit 37, it is determined whether or not the abnormal pixel determination unit 43 is abnormal in order, and the switch driving unit 39 is operated to switch the switch corresponding to the abnormal pixel. 21 may be fixed off.
  • the present invention is suitable for a two-dimensional image detector that detects an image.

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Abstract

An image capture control unit manipulates a bias applying unit and a switch drive unit so as to cause the capacitors of a plurality of detection elements to accumulate electric charges, and reads out electric charge information from all the capacitors as abnormal pixel information. Then, the capacitors with pixel information greater than or equal to a prescribed value are determined to be abnormal pixels, and the switches of those capacitors are placed in a non-conductive state by manipulation by the switch drive unit. Since the abnormal pixels are electrically cut off, the electric charge information of the other normal detection elements connected to the same data line can be correctly extracted. As a result, excessive electric charges will not be accumulated in X-ray imaging and will not adversely affect the other normal detection elements connected to the same data line at the time of read-out, so a high-quality image without defects will be able to be attained.

Description

二次元画像検出器2D image detector
　この発明は、Ｘ線等の放射線、可視光、赤外線等の電磁波による画像を検出する二次元画像検出器に関する。 The present invention relates to a two-dimensional image detector that detects an image by radiation such as X-rays, electromagnetic waves such as visible light and infrared rays.
　従来、この種の装置として、半導体層と、半導体層に生じた電荷を読み出すアクティブマトリクス基板とを備えたものがある（例えば、特許文献１参照）。半導体層は、電磁波情報を電荷情報に変換する。アクティブマトリクス基板は、半導体層で生じた電荷情報を蓄積する複数個の電荷蓄積容量と、データ線を介して各電荷蓄積情報の電荷情報を読み出すための読み出しスイッチと、半導体層と各電荷蓄積容量との間に配置され、導通状態と非導通状態とを切り換えるスイッチとを備えている。 Conventionally, as this type of device, there is a device provided with a semiconductor layer and an active matrix substrate for reading out charges generated in the semiconductor layer (for example, see Patent Document 1). The semiconductor layer converts electromagnetic wave information into charge information. The active matrix substrate includes a plurality of charge storage capacitors for storing charge information generated in the semiconductor layer, a read switch for reading the charge information of each charge storage information via the data line, the semiconductor layer, and each charge storage capacitor And a switch for switching between a conductive state and a non-conductive state.
　上記の装置は、放射線の照射と読み出しとを交互に行うスロットスキャン方式を行う場合、照射時にスイッチを導通状態とし、非照射で読み出し時にスイッチを非導通状態とする。これにより、被写体による散乱線により画質が低下するのを抑制できるようになっている。 When the above apparatus performs the slot scan method in which irradiation and reading of radiation are alternately performed, the switch is turned on during irradiation, and the switch is turned off during reading without irradiation. As a result, it is possible to suppress degradation in image quality due to scattered rays from the subject.
特開２０１０－５１６８９号公報JP 2010-51689 A
　しかしながら、このような構成を有する従来例の場合には、次のような問題がある。
　すなわち、従来の装置は、各電荷蓄積情報を読み出すためのデータ線が各画素に共通しているライン駆動となっている。そのため同じデータ線に接続された画素のいずれかにおいて、電荷蓄積容量が過剰な電荷を蓄えている場合には、その容量から溢れた電荷により、同じデータ線に接続されている他の画素の電荷に悪影響を与えることがある。過剰な電荷となる原因としては、半導体層における結晶欠陥に起因するリーク電流がある。悪影響を受けると、正常な画素であっても、画素値が上限値に張り付いてしまい、同じデータ線の画素から正常な画素情報を得られなくなるという問題がある。 However, the conventional example having such a configuration has the following problems.
That is, the conventional device is line-driven in which a data line for reading out each charge accumulation information is common to each pixel. Therefore, in any of the pixels connected to the same data line, if the charge storage capacity stores excessive charge, the charge of other pixels connected to the same data line is caused by the charge overflowing from the capacity. May be adversely affected. As a cause of excessive charge, there is a leakage current due to crystal defects in the semiconductor layer. When adversely affected, there is a problem that even if the pixel is normal, the pixel value sticks to the upper limit value, and normal pixel information cannot be obtained from pixels on the same data line.
　この発明は、このような事情に鑑みてなされたものであって、異常画素を電気的に切り離すことにより、同一データ線上に異常画素が存在しても他の画素からの電荷情報を正しく取り出すことができる二次元画像検出器を提供することを目的とする。 The present invention has been made in view of such circumstances, and by electrically disconnecting abnormal pixels, it is possible to correctly extract charge information from other pixels even if abnormal pixels exist on the same data line. An object of the present invention is to provide a two-dimensional image detector capable of
　この発明は、このような目的を達成するために、次のような構成をとる。
　すなわち、この発明は、電磁波情報を電荷情報に変換する半導体層と、前記半導体層で変換された電荷情報を蓄積する複数個の電荷蓄積容量、及びデータ線を介して前記各電荷蓄積容量の電荷情報を読み出すための読み出しスイッチを備えたアクティブマトリクス基板とを備えた二次元画像検出器において、前記半導体層と前記各電荷蓄積容量との間に配置され、導通状態と非導通状態とを画素ごとに切り換えるためのスイッチと、前記複数個の電荷蓄積容量に対して電荷を蓄積させる電荷蓄積手段と、前記スイッチのうち、任意のスイッチを導通状態と非導通状態とのいずれかに切り換えるスイッチ駆動手段と、前記電荷蓄積手段及び前記スイッチ駆動手段を操作して前記複数個の電荷蓄積容量に電荷を蓄積させ、全ての電荷蓄積容量の電荷情報を異常画素情報として取得し、異常画素情報のうち電荷情報が所定の値以上の電荷蓄積容量については、異常画素と判断して前記スイッチ駆動手段を操作して前記スイッチを非導通状態にする制御手段と、を備えていることを特徴とするものである。 In order to achieve such an object, the present invention has the following configuration.
That is, the present invention provides a semiconductor layer for converting electromagnetic wave information into charge information, a plurality of charge storage capacitors for storing charge information converted by the semiconductor layer, and a charge of each charge storage capacitor through a data line. In a two-dimensional image detector comprising an active matrix substrate having a readout switch for reading out information, the two-dimensional image detector is arranged between the semiconductor layer and each of the charge storage capacitors, and switches between a conduction state and a non-conduction state for each pixel. A switch for switching to any one of the plurality of charge storage capacitors, and a switch driving means for switching any one of the switches to a conductive state or a non-conductive state. And operating the charge storage means and the switch driving means to store charges in the plurality of charge storage capacitors, Information is acquired as abnormal pixel information, and regarding the charge storage capacitor whose charge information is greater than or equal to a predetermined value among the abnormal pixel information, it is determined as an abnormal pixel and the switch driving means is operated to make the switch non-conductive. And a control means.
　［作用・効果］この発明によれば、制御手段は、電荷蓄積手段及びスイッチ駆動手段を操作して複数個の電荷蓄積容量に電荷を蓄積させ、全ての電荷蓄積容量の電荷情報を異常画素情報として読み出す。そして、電荷蓄積容量が所定の値以上のものについては、異常画素であると判断して、その電荷蓄積容量のスイッチをスイッチ駆動手段を操作して非導通状態にする。したがって、異常画素が電気的に切り離されるので、同じデータ線に接続された他の正常な画素の電荷情報を正しく取り出すことができる。 [Operation / Effect] According to the present invention, the control means operates the charge accumulation means and the switch drive means to accumulate charges in a plurality of charge accumulation capacitors, and the charge information of all the charge accumulation capacitors is abnormal pixel information. Read as. If the charge storage capacity is greater than or equal to a predetermined value, it is determined that the pixel is an abnormal pixel, and the switch of the charge storage capacity is turned off by operating the switch driving means. Accordingly, since the abnormal pixel is electrically disconnected, the charge information of other normal pixels connected to the same data line can be correctly extracted.
　また、この発明において、前記電荷蓄積手段は、電磁波を照射して撮影を行うときのバイアス電圧より低いバイアス電圧を前記半導体層に対して印加することが好ましい。 In the present invention, it is preferable that the charge accumulating means applies a bias voltage, which is lower than a bias voltage when photographing by irradiating electromagnetic waves, to the semiconductor layer.
　半導体層に欠陥がある場合には、撮影時のバイアス電圧を加えなくても、それよりも低いバイアス電圧で電荷蓄積容量に電荷を蓄積させることができる。したがって、消費電力を抑制できる。例えば、通常の撮影時には、バイアス電圧として０．１より高く０．３Ｖ／μｍ程度を印加するが、それより低い０．１Ｖ／μｍでも異常画素を判断できる。 If there is a defect in the semiconductor layer, it is possible to store charges in the charge storage capacitor with a bias voltage lower than that without applying a bias voltage during photographing. Therefore, power consumption can be suppressed. For example, during normal photographing, a bias voltage higher than 0.1 and about 0.3 V / μm is applied, but abnormal pixels can be determined even at a lower voltage of 0.1 V / μm.
　また、この発明において、前記電荷蓄積手段は、撮影を行うときのバイアス電圧を前記半導体層に対して印加するとともに、電磁波を照射することが好ましい。 In the present invention, it is preferable that the charge accumulating unit applies a bias voltage for photographing to the semiconductor layer and irradiates an electromagnetic wave.
　撮影を行うときのバイアス電圧を印加して電磁波を照射する通常の撮影状態で異常画素の判断を行う。これにより、通常の撮影時における電磁波を照射されたときにだけ半導体層のリーク電流が増加するような場合にも異常画素を判断できる。 異常 Judgment of abnormal pixels in normal shooting state where electromagnetic waves are applied by applying a bias voltage when shooting. Thereby, it is possible to determine an abnormal pixel even when the leakage current of the semiconductor layer increases only when the electromagnetic wave is irradiated during normal photographing.
　また、この発明において、前記制御手段は、前記複数個の電荷蓄積容量の全てのスイッチを導通状態として電荷を蓄積させ、前記複数個の電荷蓄積容量の電荷情報を読み出し、その結果、異常画素を含む領域の中心部にあたる電荷蓄積容量のスイッチを非導通状態として電荷を蓄積させて電荷情報を読み出し、これを繰り返して前記異常画素情報を取得することが好ましい。 In the present invention, the control means stores all the charges by setting all the switches of the plurality of charge storage capacitors to a conductive state, reads out the charge information of the plurality of charge storage capacitors, and as a result, detects abnormal pixels. It is preferable that the charge storage capacitor switch corresponding to the center of the region including the non-conductive state is made non-conductive to store the charge, read the charge information, and repeat this to acquire the abnormal pixel information.
　半導体層の欠陥によっては、全ての電荷蓄積容量のスイッチを導通状態にして異常画素情報を取得すると、異常画素の影響により同じデータ線の他の正常な画素を誤って異常画素と判断することが生じ得る。そこで、複数個の電荷蓄積容量の全てのスイッチを導通状態として電荷を蓄積させて電荷情報を読み出す。その結果、異常画素となった領域の中心部にあたる電荷蓄積容量のスイッチを非導通状態として、再度電荷を蓄積させて電荷情報を読み取る。スイッチを非導通状態としたことにより、同じデータ線にある正常な画素の電荷情報を正しく読み出せるので、異常画素と正常画素を適切に判断することができる。このような追い込みのような異常画素の検出を行うことで、比較的短時間で異常画素情報を正確なものとすることができる。 Depending on the defect of the semiconductor layer, if abnormal pixel information is acquired with all the charge storage capacitor switches turned on, other normal pixels of the same data line may be erroneously determined as abnormal pixels due to the influence of the abnormal pixels. Can occur. Therefore, all the switches of the plurality of charge storage capacitors are turned on to store the charges and read the charge information. As a result, the charge storage capacitor switch corresponding to the center of the region that has become an abnormal pixel is set in a non-conductive state, and the charge is stored again to read the charge information. By setting the switch to the non-conductive state, the charge information of normal pixels on the same data line can be read correctly, so that abnormal pixels and normal pixels can be determined appropriately. By detecting such an abnormal pixel such as chasing, the abnormal pixel information can be made accurate in a relatively short time.
　また、この発明において、前記制御手段は、前記複数個の電荷蓄積容量のうち、一つの電荷蓄積容量のスイッチのみを導通状態とし、その他の電荷蓄積容量のスイッチを非導通状態として電荷を蓄積させ、前記一つの電荷蓄積容量の電荷情報を読み出し、順次に残りの電荷蓄積容量について一つずつスイッチを導通状態として全ての電荷蓄積容量の電荷情報を読み出して、前記異常画素情報を取得することが好ましい。 Also, in the present invention, the control means causes only one charge storage capacitor switch of the plurality of charge storage capacitors to be in a conductive state and other charge storage capacitor switches to be in a non-conductive state to store charges. , Reading out the charge information of the one charge storage capacitor, and sequentially reading out the charge information of all the charge storage capacitors by setting the switches one by one for the remaining charge storage capacitors to obtain the abnormal pixel information. preferable.
　半導体層の欠陥によっては、全ての電荷蓄積容量のスイッチを導通状態にして異常画素情報を取得すると、異常画素の影響により同じデータ線の他の正常な画素を誤って異常画素と判断することが生じ得る。そこで、複数個の電荷蓄積容量のうち、一つの電荷蓄積容量のスイッチのみを導通状態とし、その他の電荷蓄積容量のスイッチを非導通状態として電荷を蓄積させ、一つの電荷蓄積容量の電荷情報を読み出し、順次に残りの電荷蓄積容量について一つずつスイッチを導通状態として全ての電荷蓄積容量の電荷情報を読み出す。このように一つずつ異常画素の検出を行うことで、検出に時間を要するものの、異常画素情報を正確に取得できる。 Depending on the defect of the semiconductor layer, if abnormal pixel information is acquired with all the charge storage capacitor switches turned on, other normal pixels of the same data line may be erroneously determined as abnormal pixels due to the influence of the abnormal pixels. Can occur. Therefore, among the plurality of charge storage capacitors, only one charge storage capacitor switch is turned on and the other charge storage capacitor switches are turned off to store charges, and the charge information of one charge storage capacitor is stored. Read, sequentially, the charge information of all the charge storage capacitors is read by turning on the switches one by one for the remaining charge storage capacitors. By detecting abnormal pixels one by one in this way, abnormal pixel information can be obtained accurately, although detection takes time.
　また、この発明において、前記制御手段は、前記複数個の電荷蓄積容量のうち、各データ線の中で一つの電荷蓄積容量のスイッチのみを導通状態とし、同じデータ線の中で他の電荷蓄積容量のスイッチを非導通状態として電荷を蓄積させ、データ線の中で一つの電荷蓄積容量の電荷情報を読み出し、順次にデータ線の中で残りの電荷蓄積容量について一つずつスイッチを導通状態として全ての電荷蓄積容量の電荷情報を読み出して、前記異常画素情報を取得することが好ましい。 Also, in the present invention, the control means turns on only one charge storage capacitor switch in each data line among the plurality of charge storage capacitors and makes another charge storage in the same data line. Charges are stored by setting the capacitance switch to the non-conductive state, the charge information of one charge storage capacitor is read out in the data line, and the switches are sequentially turned on one by one for the remaining charge storage capacitors in the data line. It is preferable to read out the charge information of all the charge storage capacitors and acquire the abnormal pixel information.
　半導体層の欠陥によっては、全ての電荷蓄積容量のスイッチを導通状態にして異常画素情報を取得すると、異常画素の影響により同じデータ線の他の正常な画素を誤って異常画素と判断することが生じ得る。そこで、各データ線の中で一つの電荷蓄積容量のスイッチのみを導通状態とし、同じデータ線の中で他の電荷蓄積容量のスイッチを非導通状態として電荷を蓄積させ、データ線の中で一つの電荷蓄積容量の電荷情報を読み出し、順次にデータ線の中で残りの電荷蓄積容量について一つずつスイッチを導通状態として全ての電荷蓄積容量の電荷情報を読み出す。このようにデータ線の中で一つずつの異常画素の検出を行うことで、検出に要する時間を短縮しつつも、異常画素情報を正確に取得できる。 Depending on the defect of the semiconductor layer, if abnormal pixel information is acquired with all the charge storage capacitor switches turned on, other normal pixels of the same data line may be erroneously determined as abnormal pixels due to the influence of the abnormal pixels. Can occur. Therefore, only one charge storage capacitor switch in each data line is turned on, and other charge storage capacitor switches in the same data line are turned off to store charges. The charge information of one charge storage capacitor is read out, and the charge information of all the charge storage capacitors is read out by sequentially turning on the switches one by one for the remaining charge storage capacitors in the data line. By detecting each abnormal pixel in the data line in this way, it is possible to accurately acquire abnormal pixel information while reducing the time required for detection.
　また、この発明において、前記異常画素情報を記憶する記憶手段を備え、前記制御手段は、取得した異常画素情報を前記記憶手段に記憶させ、前記記憶手段に記憶させた異常画素情報に基づいて前記スイッチ駆動手段を操作することが好ましい。 According to the present invention, the storage unit stores the abnormal pixel information. The control unit stores the acquired abnormal pixel information in the storage unit, and based on the abnormal pixel information stored in the storage unit, the storage unit stores the abnormal pixel information. It is preferable to operate the switch driving means.
　異常画素情報を記憶手段に記憶することにより、制御手段が記憶手段を参照することで、スイッチ駆動手段を適切に操作できる。 By storing abnormal pixel information in the storage means, the control means can appropriately operate the switch drive means by referring to the storage means.
　また、この発明において、前記制御手段は、前記異常画素情報を定期的に取得することが好ましい。 In the present invention, it is preferable that the control means periodically acquires the abnormal pixel information.
　定期的に異常画素情報を取得することにより、半導体層の特性が経時変化で変化しても、最新の異常画素情報に基づき適切にスイッチを操作できる。 By acquiring abnormal pixel information periodically, even if the characteristics of the semiconductor layer change over time, the switch can be appropriately operated based on the latest abnormal pixel information.
　この発明に係る二次元画像検出器によれば、制御手段は、電荷蓄積手段及びスイッチ駆動手段を操作して複数個の電荷蓄積容量に電荷を蓄積させ、全ての電荷蓄積容量の電荷情報を異常画素情報として読み出す。そして、電荷蓄積容量が所定の値以上のものについては、異常画素であると判断して、その電荷蓄積容量のスイッチをスイッチ駆動手段を操作して非導通状態にする。したがって、異常画素が電気的に切り離されるので、同じデータ線に接続された他の正常な画素の電荷情報を正しく取り出すことができる。 According to the two-dimensional image detector of the present invention, the control means operates the charge storage means and the switch drive means to store charges in the plurality of charge storage capacitors, and abnormally stores the charge information of all the charge storage capacitors. Read out as pixel information. If the charge storage capacity is greater than or equal to a predetermined value, it is determined that the pixel is an abnormal pixel, and the switch of the charge storage capacity is turned off by operating the switch driving means. Accordingly, since the abnormal pixel is electrically disconnected, the charge information of other normal pixels connected to the same data line can be correctly extracted.
実施例に係る二次元画像検出器を備えたＸ線撮影装置の概略構成を示すブロック図である。It is a block diagram which shows schematic structure of the X-ray imaging apparatus provided with the two-dimensional image detector which concerns on an Example. アクティブマトリクス基板と外部回路との接続関係を示す図である。It is a figure which shows the connection relation of an active matrix substrate and an external circuit. 二次元画像検出器を模式的に示した縦断面図である。It is the longitudinal cross-sectional view which showed the two-dimensional image detector typically. 撮影制御部の要部を示すブロック図である。It is a block diagram which shows the principal part of an imaging | photography control part. 異常画素情報を取得する手順を示したフローチャートである。It is the flowchart which showed the procedure which acquires abnormal pixel information.
　以下、図面を参照してこの発明の一実施例を説明する。
　図１は、実施例に係る二次元画像検出器を備えたＸ線撮影装置の概略構成を示すブロック図である。 An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram illustrating a schematic configuration of an X-ray imaging apparatus including a two-dimensional image detector according to an embodiment.
　天板１は、Ｘ線を透過する部材で構成され、検査対象である被検体Ｍが載置される。天板１の上方には、Ｘ線管３が配置されている。天板１を挟んだＸ線管３の反対側には、フラットパネル検出器５が配置されている。 The top plate 1 is made of a member that transmits X-rays, and a subject M to be examined is placed thereon. An X-ray tube 3 is disposed above the top plate 1. A flat panel detector 5 is disposed on the opposite side of the X-ray tube 3 across the top plate 1.
　なお、上記のフラットパネル検出器５が本発明における「二次元画像検出器」に相当する。 The flat panel detector 5 described above corresponds to the “two-dimensional image detector” in the present invention.
　撮影制御部７は、Ｘ線管３からのＸ線照射を制御する照射制御部９を制御する。照射制御部９の制御は、撮影者によって操作されるキーボード１１やマウス１３からの指示に応じて、撮影制御部７から出力される指令信号によって行われる。キーボード１１やマウス１３からは、Ｘ線管３のＸ線照射強度や照射時間などの情報が指示される。 The imaging control unit 7 controls an irradiation control unit 9 that controls X-ray irradiation from the X-ray tube 3. The irradiation control unit 9 is controlled by a command signal output from the imaging control unit 7 in response to an instruction from the keyboard 11 or mouse 13 operated by the photographer. Information such as the X-ray irradiation intensity and irradiation time of the X-ray tube 3 is instructed from the keyboard 11 and the mouse 13.
　フラットパネル検出器５で検出された透過Ｘ線に応じた信号（後述する電荷情報を含む信号）は、信号収集部１５によって収集される。収集された信号は、データ処理部１７において処理され、Ｘ線画像がモニタ１９に表示される。フラットパネル検出器５には、後述する電極層３３にバイアス電圧を印加するためのバイアス印加部２１が接続されている。このバイアス印加部２１は、撮影制御部７で制御される。 Signals corresponding to transmitted X-rays detected by the flat panel detector 5 (signals including charge information described later) are collected by the signal collecting unit 15. The collected signal is processed in the data processing unit 17 and an X-ray image is displayed on the monitor 19. The flat panel detector 5 is connected to a bias applying unit 21 for applying a bias voltage to an electrode layer 33 described later. The bias application unit 21 is controlled by the imaging control unit 7.
　なお、バイアス印加部２１及びＸ線管３が本発明における「電荷蓄積手段」に相当する。 The bias applying unit 21 and the X-ray tube 3 correspond to the “charge storage unit” in the present invention.
　ここで図２，図３を参照して、フラットパネル検出器５について詳細に説明する。なお、図２は、アクティブマトリクス基板と外部回路との接続関係を示す図であり、図３は、二次元画像検出器を模式的に示した縦断面図である。 Here, the flat panel detector 5 will be described in detail with reference to FIGS. 2 is a diagram showing the connection relationship between the active matrix substrate and the external circuit, and FIG. 3 is a longitudinal sectional view schematically showing the two-dimensional image detector.
　アクティブマトリクス基板２３は、検出素子ＤＵが二次元マトリクス状に配置されており、ガラス等の絶縁基板２５にパターン形成されている。アクティブマトリクス基板２３は、キャリア収集電極２７と、「電荷蓄積容量」に相当するコンデンサＣａと、薄膜トランジスタＴｒとを備えている。キャリア収集電極２７は、半導体層２９で変換された電荷情報を収集する。コンデンサＣａは、キャリア収集電極２７で収集された電荷情報を蓄積する。本発明における「読み出しスイッチ」に相当する薄膜トランジスタＴｒは、外部信号によりオンオフに切り換えられ、コンデンサＣａに蓄積された電荷情報を読み出すスイッチング素子である。 In the active matrix substrate 23, the detection elements DU are arranged in a two-dimensional matrix, and a pattern is formed on an insulating substrate 25 such as glass. The active matrix substrate 23 includes a carrier collection electrode 27, a capacitor Ca corresponding to “charge storage capacity”, and a thin film transistor Tr. The carrier collection electrode 27 collects charge information converted by the semiconductor layer 29. The capacitor Ca stores the charge information collected by the carrier collection electrode 27. The thin film transistor Tr corresponding to the “read switch” in the present invention is a switching element that is turned on and off by an external signal and reads the charge information stored in the capacitor Ca.
　半導体層２９及びキャリア収集電極２７とコンデンサＣａとの間には、スイッチ３１が設けられている。本発明における「画素」に相当する一つの検出素子ＤＵは、キャリア収集電極２７と、コンデンサＣａと、スイッチ３１と、薄膜トランジスタＴｒと、これらに応じた領域の半導体層２９及び電極層３３とで構成されている。電極層３３には、バイアス印加部２１によりバイアス電圧Ｖａが印加される。アクティブマトリクス基板２３の二次元マトリクスは、例えば、１５３６×１５３６個の検出素子ＤＵで構成されているが、説明の理解を容易にするために３×３個に簡略化してある。スイッチ３１は、ノーマリクローズ型であることが好ましい。これは、後述するように異常がある検出素子ＤＵについてはスイッチ３１をオフするが、その個数は正常な検出素子ＤＵに比べて少ないのが一般的である。したがって、ノーマリクローズ型のスイッチ３１とすることで、オフするための駆動電力を低減することができる。 A switch 31 is provided between the semiconductor layer 29 and the carrier collecting electrode 27 and the capacitor Ca. One detection element DU corresponding to a “pixel” in the present invention includes a carrier collection electrode 27, a capacitor Ca, a switch 31, a thin film transistor Tr, and a semiconductor layer 29 and an electrode layer 33 in regions corresponding to these. Has been. A bias voltage Va is applied to the electrode layer 33 by the bias applying unit 21. The two-dimensional matrix of the active matrix substrate 23 is composed of, for example, 1536 × 1536 detection elements DU, but is simplified to 3 × 3 for easy understanding of the description. The switch 31 is preferably a normally closed type. As will be described later, the switch 31 is turned off for a detection element DU having an abnormality, but the number of detection elements DU is generally smaller than that of a normal detection element DU. Therefore, the drive power for turning off can be reduced by using the normally closed switch 31.
　なお、上述した半導体層２９は、例えば、暗抵抗が高く、Ｘ線照射に対して良好な光導電特性を示し、蒸着によって大面積の成膜が可能な非結晶セレニウム（アモルファスセレニウム（ａ－Ｓｅ））であることが好ましい。また、半導体層２９は、例えば、真空蒸着法によって３００～１２００μｍの厚みで形成されている。 The above-described semiconductor layer 29 has, for example, a high dark resistance, a good photoconductive property against X-ray irradiation, and an amorphous selenium (amorphous selenium (a-Se) that can be formed into a large area by vapor deposition. )). The semiconductor layer 29 is formed with a thickness of 300 to 1200 μm by, for example, vacuum deposition.
　半導体層２９としては、ＣｄＺｎＴｅのような結晶構造で、より多くの電荷を発生させる材料を用いることもできる。半導体層２９にＣｄＺｎＴｅを用いる場合には、昇華法によって形成するのが好ましい。Ｘ線撮影装置では、数十～数百ｋｅＶのエネルギーを照射するために、厚みが１００～６００μｍのＺｎを数～数十モル％含んだものを近接昇華法で成膜するのが好ましい。 As the semiconductor layer 29, a material that has a crystal structure such as CdZnTe and generates more charge can be used. When CdZnTe is used for the semiconductor layer 29, it is preferably formed by a sublimation method. In an X-ray imaging apparatus, in order to irradiate energy of several tens to several hundreds keV, it is preferable to form a film containing Zn having a thickness of 100 to 600 μm containing several to several tens mol% by the proximity sublimation method.
　アクティブマトリクス基板２３は、ゲート線Ｇ１～Ｇ３とデータ線Ｄ１～Ｄ３とを備えている。ゲート線Ｇ１～Ｇ３は、検出素子ＤＵの行ごとに薄膜トランジスタＴｒのゲートに電気的に接続されている。データ線Ｄ１～Ｄ３は、検出素子ＤＵの列ごとに薄膜トランジスタＴｒの読み出し側に電気的に接続されている。また、アクティブマトリクス基板２３は、検出素子ＤＵごとにスイッチ線ＳＬ１～ＳＬ３を備えている。スイッチ線ＳＬ１～ＳＬ３は、全検出素子ＤＵのスイッチ３１の導通状態と非導通状態とを個別に切り換えるものである。図２においては、図示の関係上、行ごとにスイッチ線ＳＬ１～ＳＬ３を描いてあるが、各検出素子ＤＵのスイッチ３１を個別に導通状態と非導通状態とに切り換えることができる。なお、以下の説明において、ゲート線Ｇ１～Ｇ３及びデータ線Ｄ１～Ｄ３並びにスイッチ線ＳＬ１～ＳＬ３を特に区別しない場合には、ゲートラインＧ及びデータラインＤ並びにスイッチ線ＳＬと称する。 The active matrix substrate 23 includes gate lines G1 to G3 and data lines D1 to D3. The gate lines G1 to G3 are electrically connected to the gate of the thin film transistor Tr for each row of the detection elements DU. The data lines D1 to D3 are electrically connected to the reading side of the thin film transistor Tr for each column of the detection elements DU. Further, the active matrix substrate 23 includes switch lines SL1 to SL3 for each detection element DU. The switch lines SL1 to SL3 are for individually switching between the conductive state and the nonconductive state of the switch 31 of all the detection elements DU. In FIG. 2, switch lines SL1 to SL3 are drawn for each row for the sake of illustration, but the switches 31 of each detection element DU can be individually switched between a conductive state and a non-conductive state. In the following description, the gate lines G1 to G3, the data lines D1 to D3, and the switch lines SL1 to SL3 are referred to as the gate line G, the data line D, and the switch line SL unless particularly distinguished.
　ゲート線Ｇ１～Ｇ３は、ゲート駆動部３５に接続されている。また、データ線Ｄ１～Ｄ３は、データ読み出し部３７に接続されている。このデータ読み出し部３７は、電荷電圧変換アンプ、マルチプレクサ、Ａ／Ｄ変換器を内蔵している。また、スイッチ線ＳＬ１～ＳＬ３は、スイッチ駆動部３９に接続されている。 The gate lines G1 to G3 are connected to the gate drive unit 35. Further, the data lines D 1 to D 3 are connected to the data reading unit 37. The data reading unit 37 includes a charge / voltage conversion amplifier, a multiplexer, and an A / D converter. The switch lines SL1 to SL3 are connected to the switch drive unit 39.
　ゲート駆動部３５は、ゲート線Ｇ１～Ｇ３に電圧を印加することで、薄膜トランジスタＴｒをオンにさせ、コンデンサＣａに蓄積された電荷情報をデータ線Ｄからデータ読み出し部３７に出力させる。データ読み出し部３７は、受け取った電荷情報を電圧信号に変換し、複数の電圧信号を一つの電圧信号とし、電圧信号をデジタル信号に変換して出力する。このように変換された全ての電荷情報は、信号収集部１５にて収集される。スイッチ駆動部３９は、後述する異常画素判断部４３の指示により、任意の検出素子ＤＵのスイッチ３１を導通状態と非導通状態のいずれかに切り換える。 The gate driver 35 applies a voltage to the gate lines G1 to G3 to turn on the thin film transistor Tr and output the charge information stored in the capacitor Ca from the data line D to the data reading unit 37. The data reading unit 37 converts the received charge information into a voltage signal, converts the plurality of voltage signals into one voltage signal, converts the voltage signal into a digital signal, and outputs the digital signal. All the charge information converted in this way is collected by the signal collecting unit 15. The switch drive unit 39 switches the switch 31 of any detection element DU between the conductive state and the non-conductive state according to an instruction from an abnormal pixel determination unit 43 described later.
　なお、スイッチ駆動部３９が本発明における「スイッチ駆動手段」に相当する。 The switch drive unit 39 corresponds to the “switch drive means” in the present invention.
　上述した撮影制御部７について、図４を参照して説明する。なお、図４は、撮影制御部の要部を示すブロック図である。 The above-described photographing control unit 7 will be described with reference to FIG. FIG. 4 is a block diagram illustrating a main part of the imaging control unit.
　撮影制御部７は、上述したように照射制御部９を制御したり、バイアス印加部２１を制御したりする他、次のような制御も行う。 The imaging control unit 7 controls the irradiation control unit 9 and the bias application unit 21 as described above, and also performs the following control.
　撮影制御部７は、異常画素情報メモリ４１と、異常画素判断部４３とを備えている。異常画素メモリ４１は、撮影制御部７の制御の下、異常画素情報の取得処理により得られた異常画素情報を記憶する。異常画素判断部４３は、異常画素情報メモリ４１にアクセスし、異常画素情報における各検出素子ＤＵの電荷情報と、予め設定された所定の値との比較を行って、どの検出素子ＤＵが異常であるかを判断する。そして、異常画素判断部４３は、異常であると判断した検出素子ＤＵのスイッチ３１を、スイッチ駆動部３９を操作して非導通状態に設定する。 The imaging control unit 7 includes an abnormal pixel information memory 41 and an abnormal pixel determination unit 43. The abnormal pixel memory 41 stores abnormal pixel information obtained by the abnormal pixel information acquisition process under the control of the imaging control unit 7. The abnormal pixel determination unit 43 accesses the abnormal pixel information memory 41, compares the charge information of each detection element DU in the abnormal pixel information with a predetermined value, and determines which detection element DU is abnormal. Determine if there is. Then, the abnormal pixel determination unit 43 sets the switch 31 of the detection element DU that has been determined to be abnormal by operating the switch driving unit 39 to a non-conductive state.
　なお、上述した撮影制御部７が本発明における「制御手段」に相当する。 The above-described photographing control unit 7 corresponds to the “control unit” in the present invention.
　次に、図５を参照して上述した装置おける異常画素情報の取得動作について説明する。図５は、異常画素情報を取得する手順を示したフローチャートである。なお、この異常画素情報の取得は、Ｘ線撮影装置による被検体Ｍの撮影を行う前に行う処理である。好ましくは、フラットパネル検出器５の半導体層２９における経時変化を考慮して、撮影ごとに行ったり、装置の起動時に行ったり、定期的に行うことがより好ましい。これにより半導体層２９の経時変化にかかわらず、適切にスイッチ３１を操作でき、長期間にわたって異常画素によるアーティファクトがない撮影画像を得ることができる。 Next, an operation for acquiring abnormal pixel information in the above-described apparatus will be described with reference to FIG. FIG. 5 is a flowchart showing a procedure for acquiring abnormal pixel information. The acquisition of abnormal pixel information is a process performed before the subject M is imaged by the X-ray imaging apparatus. Preferably, taking into account the change over time in the semiconductor layer 29 of the flat panel detector 5, it is more preferably performed at every photographing, at the start-up of the apparatus, or periodically. Accordingly, the switch 31 can be appropriately operated regardless of a change in the semiconductor layer 29 with time, and a captured image free from artifacts due to abnormal pixels can be obtained over a long period of time.
　ステップＳ１
　撮影制御部７は、フラットパネル検出器５にバイアス電圧Ｖａを印加する。このときのバイアス電圧Ｖａは、半導体層２９において発生した電荷を加速させる必要性がないので、Ｘ線照射による撮影時におけるバイアス電圧Ｖａよりも低くてもよい。例えば、通常のＸ線撮影時には０．３Ｖ／μｍ程度のバイアス電圧Ｖａを印加するので、それよりも低いバイアス電圧Ｖａ（例えば０．１Ｖ／μｍ）を印加すればよい。これにより消費電力を抑制できる。 Step S1
The imaging control unit 7 applies a bias voltage Va to the flat panel detector 5. The bias voltage Va at this time may be lower than the bias voltage Va at the time of imaging by X-ray irradiation because there is no need to accelerate the charge generated in the semiconductor layer 29. For example, since the bias voltage Va of about 0.3 V / μm is applied during normal X-ray imaging, a lower bias voltage Va (for example, 0.1 V / μm) may be applied. Thereby, power consumption can be suppressed.
　ステップＳ２
　異常画素情報を取得する。バイアス電圧Ｖａを印加した状態で、撮影制御部７は、フラットパネル検出器５から各検出素子ＤＵの電荷情報を収集する。具体的には、ゲート線Ｇ１～Ｇ３を順次にオンさせて、データ読み出し部３７を介して全ての検出素子ＤＵから電荷情報を収集する。全ての検出素子ＤＵから得られた電荷情報は、異常画素情報として異常画素情報メモリ４１に記憶される。 Step S2
Abnormal pixel information is acquired. In a state where the bias voltage Va is applied, the imaging control unit 7 collects the charge information of each detection element DU from the flat panel detector 5. Specifically, the gate lines G1 to G3 are sequentially turned on, and charge information is collected from all the detection elements DU via the data reading unit 37. The charge information obtained from all the detection elements DU is stored in the abnormal pixel information memory 41 as abnormal pixel information.
　ステップＳ３
　異常画素情報に基づいて異常画素を判断する。異常画素判断部４３は、異常画素情報メモリ４１の異常画素情報を参照して、どの検出素子ＤＵに異常があるかを判断する。具体的には、例えば、Ｘ線撮影時における検出素子ＤＵにおける出力の最大値（最大の電荷情報）を基準にして、１０％を超える値である場合には、その検出素子ＤＵが異常であると判断する。これはバイアス電圧Ｖａが低い上に、Ｘ線照射も行っていない状態であるにもかかわらず、出力の最大値に対して１０％もの電荷情報が生じることは、正常な検出素子ＤＵではあり得ないからである。なお、バイアス電圧Ｖａが低く、電荷情報が小さいので、異常がある検出素子ＤＵが同じデータ線Ｄの他の検出素子ＤＵに悪影響を与える確率は十分に低い。したがって、この場合に他の検出素子ＤＵが異常な検出素子ＤＵの悪影響により誤って異常があると判断される確率は十分に低い。但し、検出素子ＤＵの欠陥等によっては、異常画素情報の取得において同じデータ線Ｄにおける他の検出素子ＤＵに異常があると誤って判断させる状況も生じ得る。これを回避する手法については変形例において後述する。 Step S3
An abnormal pixel is determined based on the abnormal pixel information. The abnormal pixel determination unit 43 refers to the abnormal pixel information in the abnormal pixel information memory 41 to determine which detection element DU is abnormal. Specifically, for example, when the value exceeds 10% with reference to the maximum output value (maximum charge information) at the detection element DU during X-ray imaging, the detection element DU is abnormal. Judge. It is possible for the normal detection element DU to generate 10% of charge information with respect to the maximum output value even though the bias voltage Va is low and X-ray irradiation is not performed. Because there is no. Since the bias voltage Va is low and the charge information is small, the probability that an abnormal detection element DU adversely affects other detection elements DU of the same data line D is sufficiently low. Therefore, in this case, the probability that another detection element DU is erroneously determined to be abnormal due to an adverse effect of the abnormal detection element DU is sufficiently low. However, depending on a defect or the like of the detection element DU, there may be a situation in which it is erroneously determined that another detection element DU on the same data line D is abnormal in acquiring abnormal pixel information. A technique for avoiding this will be described later in a modification.
　ステップＳ４
　異常画素のスイッチ３１を非導通状態にする。異常画素判断部４３は、判断結果に基づいて、フラットパネル検出器５のスイッチ駆動部３９を操作する。具体的には、異常画素であると判断された全ての検出素子ＤＵのスイッチ３１を非導通状態となるように設定する。これにより、異常画素である検出素子ＤＵが電気的に切り離される。 Step S4
The abnormal pixel switch 31 is turned off. The abnormal pixel determination unit 43 operates the switch drive unit 39 of the flat panel detector 5 based on the determination result. Specifically, the switches 31 of all the detection elements DU that are determined to be abnormal pixels are set to be in a non-conductive state. Thereby, the detection element DU which is an abnormal pixel is electrically separated.
　上述した異常画素情報の取得を行って異常画素の切り離しを行った後に、撮影制御部７は、被検体Ｍに対してＸ線を照射してＸ線撮影を行う。 After acquiring abnormal pixel information as described above and separating abnormal pixels, the imaging control unit 7 performs X-ray imaging by irradiating the subject M with X-rays.
　本実施例によると、撮影制御部７は、バイアス印加部２１及びスイッチ駆動部３９を操作して複数個の検出素子ＤＵのコンデンサＣａに電荷を蓄積させ、全てのコンデンサＣａの電荷情報を異常画素情報として読み出す。そして、コンデンサＣａの画素情報が所定の値以上のものについては、異常画素であると判断して、そのコンデンサＣａのスイッチ３１を、スイッチ駆動部３９を操作して非導通状態にする。したがって、異常画素が電気的に切り離されるので、同じデータ線Ｄに接続された他の正常な検出素子ＤＵの電荷情報を正しく取り出すことができる。その結果、Ｘ線撮影時に過剰な電荷を蓄積して、読み出し時に同一データ線Ｄの他の正常な検出素子ＤＵに対して悪影響を与えることがなく、高品質の画像を得ることができる。 According to the present embodiment, the imaging control unit 7 operates the bias applying unit 21 and the switch driving unit 39 to accumulate charges in the capacitors Ca of the plurality of detection elements DU, and stores the charge information of all the capacitors Ca as abnormal pixels. Read as information. If the pixel information of the capacitor Ca is greater than or equal to a predetermined value, it is determined that the pixel is an abnormal pixel, and the switch 31 of the capacitor Ca is operated to operate in a non-conductive state. Therefore, since the abnormal pixel is electrically disconnected, the charge information of other normal detection elements DU connected to the same data line D can be correctly extracted. As a result, it is possible to obtain a high-quality image without accumulating excessive charges during X-ray imaging and without adversely affecting other normal detection elements DU of the same data line D during reading.
　次に、上述した異常画素情報の取得の変形例について説明する。 Next, a modified example of obtaining the abnormal pixel information described above will be described.
　異常画素情報の同一データ線Ｄにおいて、複数個の検出素子ＤＵに異常が存在した場合には、異常がある検出素子ＤＵのコンデンサＣａに極めて大量の電荷情報が蓄積され、これが同一ライン線Ｄにおける他の正常な検出素子ＤＵの電荷情報に悪影響を与えた結果である恐れがある。上述した実施例のようにバイアス電圧Ｖａが低く、Ｘ線の照射も行わない場合には電荷情報が小さいので、そのような悪影響が生じ難い。しかし、バイアス電圧Ｖａを高くしたり、Ｘ線照射を同時に行ったりした場合には、上記の事態が生じ得る。このような状態では、異常画素情報に基づきスイッチ３１を操作しても、異常がある検出素子ＤＵに加え、周囲の正常な検出素子ＤＵをもオフにしてしまうことになる。このような誤判断を回避するために以下のようにするのが好ましい。 If there is an abnormality in a plurality of detection elements DU in the same data line D of abnormal pixel information, a very large amount of charge information is accumulated in the capacitor Ca of the detection element DU having an abnormality. This may be a result of adversely affecting the charge information of other normal detection elements DU. When the bias voltage Va is low and the X-ray irradiation is not performed as in the above-described embodiment, the charge information is small, so that such an adverse effect is unlikely to occur. However, when the bias voltage Va is increased or X-ray irradiation is performed simultaneously, the above situation can occur. In such a state, even if the switch 31 is operated based on the abnormal pixel information, the surrounding normal detection elements DU are also turned off in addition to the abnormal detection elements DU. In order to avoid such misjudgment, the following is preferable.
　（変形例１）
　全ての検出素子ＤＵの全てのスイッチ３１を導通状態として電荷を蓄積させ、複数個の検出素子ＤＵの電荷情報を読み出す。その結果、異常画素情報において異常である検出素子ＤＵを含む領域の中心部にあたる検出素子ＤＵのスイッチ３１のみを非導通状態とし、再び電荷情報を蓄積させて画素情報を読み出す。その検出素子ＤＵだけが異常である場合には、この状態で異常画素情報を再取得すると、周囲の検出素子ＤＵは正常となる場合がある。これを適宜の回数だけ繰り返して追い込みを図ることにより、異常画素情報を取得する。 (Modification 1)
All the switches 31 of all the detection elements DU are turned on to accumulate charges, and the charge information of the plurality of detection elements DU is read. As a result, only the switch 31 of the detection element DU corresponding to the center of the region including the detection element DU that is abnormal in the abnormal pixel information is set in a non-conductive state, charge information is accumulated again, and pixel information is read out. If only the detection element DU is abnormal, the surrounding detection element DU may become normal if abnormal pixel information is reacquired in this state. Abnormal pixel information is acquired by repeating this process an appropriate number of times and attempting to drive it.
　このようにすると、異常がある検出素子ＤＵと正常な検出素子ＤＵとを適切に判断することができる異常画素情報を取得できる。したがって、比較的短時間で異常画素情報を正確なものとすることができる。 In this way, it is possible to acquire abnormal pixel information that can appropriately determine the abnormal detection element DU and the normal detection element DU. Therefore, the abnormal pixel information can be made accurate in a relatively short time.
　（変形例２）
　全ての検出素子ＤＵのうち、一つの検出素子ＤＵのスイッチ３１のみを導通状態とし、その他の検出素子ＤＵのスイッチ３１を非導通状態として電荷を蓄積させ、その一つの検出素子ＤＵの電荷情報を読み出す。そして、残りの検出素子ＤＵについて一つずつ順番にスイッチ３１を導通状態として全ての検出素子ＤＵの電荷情報を読み出す。これにより、異常画素情報を取得する。 (Modification 2)
Of all the detection elements DU, only the switch 31 of one detection element DU is turned on, and the switches 31 of other detection elements DU are turned off to accumulate charges, and the charge information of that one detection element DU is stored. read out. Then, the switch 31 is turned on one by one for the remaining detection elements DU, and the charge information of all the detection elements DU is read out. Thereby, abnormal pixel information is acquired.
　このように一つずつ検出素子ＤＵの電荷情報の検出を行うことで、検出に時間を要するものの、異常画素情報を正確に取得できる。 In this way, by detecting the charge information of the detection element DU one by one, the abnormal pixel information can be accurately acquired although it takes time to detect.
　（変形例３）
　全ての検出素子ＤＵのうち、各データ線Ｄの中で一つの検出素子ＤＵのスイッチ３１のみを導通状態とし、同じデータ線Ｄの中で他の検出素子ＤＵのスイッチ３１を非導通状態として電荷を蓄積させ、データ線Ｄの中で一つの検出素子ＤＵの電荷情報を読み出す。そして、順次にデータ線Ｄの中で残りの検出素子ＤＵについて一つずつスイッチ３１を導通状態として全ての検出素子ＤＵの電荷情報を読み出して、異常画素情報を取得する。 (Modification 3)
Among all the detection elements DU, only the switch 31 of one detection element DU in each data line D is made conductive, and the switch 31 of the other detection element DU is made non-conductive in the same data line D. And the charge information of one detection element DU in the data line D is read out. Then, the switch 31 is sequentially turned on one by one for the remaining detection elements DU in the data line D, and the charge information of all the detection elements DU is read to acquire abnormal pixel information.
　このようにデータ線Ｄの中で一つずつの検出素子ＤＵの電荷情報を検出することで、検出に要する時間を短縮しつつも、異常画素情報を正確に取得できる。 Thus, by detecting the charge information of each detection element DU in the data line D, it is possible to accurately acquire abnormal pixel information while reducing the time required for detection.
　この発明は、上記実施形態に限られることはなく、下記のように変形実施することができる。 The present invention is not limited to the above embodiment, and can be modified as follows.
　（１）上述した実施例では、異常画素情報の取得時に、Ｘ線撮影時よりも低いバイアス電圧Ｖａのみを印加した。しかしながら、Ｘ線撮影時のバイアス電圧Ｖａを加えるとともに、Ｘ線管３からＸ線を照射して異常画素情報の取得を行うようにしてもよい。これにより、例えば、Ｘ線照射時にのみリーク電流が増大したりする欠陥を抱えた検出素子ＤＵをも異常画素として検出することができる。 (1) In the above-described embodiment, only the bias voltage Va lower than that at the time of X-ray imaging is applied when acquiring abnormal pixel information. However, the bias voltage Va at the time of X-ray imaging may be applied, and X-rays may be irradiated from the X-ray tube 3 to acquire abnormal pixel information. Thereby, for example, a detection element DU having a defect in which a leakage current increases only at the time of X-ray irradiation can be detected as an abnormal pixel.
　（２）上述した実施例では、異常画素情報メモリ４１を備え、ここに異常画素情報を記憶するようにした。しかし、異常画素情報メモリ４１を必ずしも備える必要はない。その場合には、データ読み出し部３７から異常画素情報を読み出しつつ異常画素判断部４３が逐次的に異常であるか否かを判断して、スイッチ駆動部３９を操作し、異常画素に対応するスイッチ２１をオフで固定するようにすればよい。 (2) In the above-described embodiment, the abnormal pixel information memory 41 is provided, and abnormal pixel information is stored therein. However, the abnormal pixel information memory 41 is not necessarily provided. In that case, while reading abnormal pixel information from the data reading unit 37, it is determined whether or not the abnormal pixel determination unit 43 is abnormal in order, and the switch driving unit 39 is operated to switch the switch corresponding to the abnormal pixel. 21 may be fixed off.
　以上のように、この発明は、画像を検出する二次元画像検出器に適している。 As described above, the present invention is suitable for a two-dimensional image detector that detects an image.
　Ｍ　…　被検体
　１　…　天板
　３　…　Ｘ線管
　５　…　フラットパネル検出器
　７　…　撮影制御部
　９　…　照射制御部
　２１　…　バイアス印加部
　２３　…　アクティブマトリクス基板
　ＤＵ　…　検出素子
　２５　…　絶縁基板
　２７　…　キャリア収集電極
　Ｃａ　…　コンデンサ
　Ｔｒ　…　薄膜トランジスタ
　２９　…　半導体層
　３１　…　スイッチ
　３３　…　電極層
　Ｖａ　…　バイアス電圧
　Ｇ１～Ｇ３　…　ゲート線
　Ｄ１～Ｄ３　…　データ線
　ＳＬ１～ＳＬ３　…　スイッチ線
　３５　…　ゲート駆動部
　３７　…　データ読み出し部
　３９　…　スイッチ駆動部
　４１　…　異常画素メモリ
　４３　…　異常画素判断部 M ... Subject 1 ... Top plate 3 ... X-ray tube 5 ... Flat panel detector 7 ... Imaging control unit 9 ... Irradiation control unit 21 ... Bias application unit 23 ... Active matrix substrate DU ... Detection element 25 ... Insulating substrate 27 ... Carrier Collection electrode Ca ... Capacitor Tr ... Thin film transistor 29 ... Semiconductor layer 31 ... Switch 33 ... Electrode layer Va ... Bias voltage G1-G3 ... Gate line D1-D3 ... Data line SL1-SL3 ... Switch line 35 ... Gate drive part 37 ... Data read-out Unit 39 ... Switch drive unit 41 ... Abnormal pixel memory 43 ... Abnormal pixel determination unit

Claims (8)

  1. 　電磁波情報を電荷情報に変換する半導体層と、前記半導体層で変換された電荷情報を蓄積する複数個の電荷蓄積容量、及びデータ線を介して前記各電荷蓄積容量の電荷情報を読み出すための読み出しスイッチを備えたアクティブマトリクス基板とを備えた二次元画像検出器において、
    　前記半導体層と前記各電荷蓄積容量との間に配置され、導通状態と非導通状態とを画素ごとに切り換えるためのスイッチと、
    　前記複数個の電荷蓄積容量に対して電荷を蓄積させる電荷蓄積手段と、
    　前記スイッチのうち、任意のスイッチを導通状態と非導通状態とのいずれかに切り換えるスイッチ駆動手段と、
    　前記電荷蓄積手段及び前記スイッチ駆動手段を操作して前記複数個の電荷蓄積容量に電荷を蓄積させ、全ての電荷蓄積容量の電荷情報を異常画素情報として取得し、異常画素情報のうち電荷情報が所定の値以上の電荷蓄積容量については、異常画素と判断して前記スイッチ駆動手段を操作して前記スイッチを非導通状態にする制御手段と、
    　を備えていることを特徴とする二次元画像検出器。     A semiconductor layer for converting electromagnetic wave information into charge information, a plurality of charge storage capacitors for storing charge information converted by the semiconductor layer, and reading for reading out charge information of each charge storage capacitor via a data line In a two-dimensional image detector comprising an active matrix substrate with a switch,
    A switch that is disposed between the semiconductor layer and each of the charge storage capacitors, and switches between a conductive state and a non-conductive state for each pixel;
    Charge storage means for storing charge in the plurality of charge storage capacitors;
    Of the switches, switch driving means for switching any switch between a conductive state and a non-conductive state;
    The charge storage means and the switch driving means are operated to store charges in the plurality of charge storage capacitors, and charge information of all the charge storage capacitors is acquired as abnormal pixel information. For a charge storage capacity greater than or equal to a predetermined value, a control means that determines that the pixel is an abnormal pixel and operates the switch driving means to place the switch in a non-conductive state;
    A two-dimensional image detector.
  2. 　請求項１に記載の二次元画像検出器において、
    　前記電荷蓄積手段は、電磁波を照射して撮影を行うときのバイアス電圧より低いバイアス電圧を前記半導体層に対して印加することを特徴とする二次元画像検出器。     The two-dimensional image detector according to claim 1,
    The two-dimensional image detector, wherein the charge accumulating means applies a bias voltage to the semiconductor layer that is lower than a bias voltage when photographing by irradiating electromagnetic waves.
  3. 　請求項１に記載の二次元画像検出器において、
    　前記電荷蓄積手段は、撮影を行うときのバイアス電圧を前記半導体層に対して印加するとともに、電磁波を照射することを特徴とする二次元画像検出器。     The two-dimensional image detector according to claim 1,
    The two-dimensional image detector, wherein the charge accumulating unit applies a bias voltage for photographing to the semiconductor layer and emits an electromagnetic wave.
  4. 　請求項１から３のいずれかに記載の二次元画像検出器において、
    　前記制御手段は、前記複数個の電荷蓄積容量の全てのスイッチを導通状態として電荷を蓄積させ、前記複数個の電荷蓄積容量の電荷情報を読み出し、その結果、異常画素を含む領域の中心部にあたる電荷蓄積容量のスイッチを非導通状態として電荷を蓄積させて電荷情報を読み出し、これを繰り返して前記異常画素情報を取得することを特徴とする二次元画像検出器。     The two-dimensional image detector according to any one of claims 1 to 3,
    The control means sets all the switches of the plurality of charge storage capacitors in a conductive state to store charges, reads the charge information of the plurality of charge storage capacitors, and as a result, corresponds to the center of a region including abnormal pixels A two-dimensional image detector characterized in that a charge storage capacitor switch is set in a non-conducting state to accumulate charges and read out charge information, and repeat this to acquire the abnormal pixel information.
  5. 　請求項１から３のいずれかに記載の二次元画像検出器において、
    　前記制御手段は、前記複数個の電荷蓄積容量のうち、一つの電荷蓄積容量のスイッチのみを導通状態とし、その他の電荷蓄積容量のスイッチを非導通状態として電荷を蓄積させ、前記一つの電荷蓄積容量の電荷情報を読み出し、順次に残りの電荷蓄積容量について一つずつスイッチを導通状態として全ての電荷蓄積容量の電荷情報を読み出して、前記異常画素情報を取得することを特徴とする二次元画像検出器。     The two-dimensional image detector according to any one of claims 1 to 3,
    The control means stores only one charge storage capacitor among the plurality of charge storage capacitors in a conductive state and stores other charge storage capacitor switches in a non-conductive state to store the one charge storage. A two-dimensional image characterized by reading out the charge information of the capacitors and sequentially reading out the charge information of all the charge storage capacitors with the switches one by one for the remaining charge storage capacitors to obtain the abnormal pixel information. Detector.
  6. 　請求項１から３のいずれかに記載の二次元画像検出器において、
    　前記制御手段は、前記複数個の電荷蓄積容量のうち、各データ線の中で一つの電荷蓄積容量のスイッチのみを導通状態とし、同じデータ線の中で他の電荷蓄積容量のスイッチを非導通状態として電荷を蓄積させ、データ線の中で一つの電荷蓄積容量の電荷情報を読み出し、順次にデータ線の中で残りの電荷蓄積容量について一つずつスイッチを導通状態として全ての電荷蓄積容量の電荷情報を読み出して、前記異常画素情報を取得することを特徴とする二次元画像検出器。     The two-dimensional image detector according to any one of claims 1 to 3,
    The control means turns on only one charge storage capacitor switch in each data line among the plurality of charge storage capacitors, and turns off the other charge storage capacitor switch in the same data line. The charge is stored as a state, the charge information of one charge storage capacitor is read out in the data line, and the switches are sequentially turned on one by one for the remaining charge storage capacitors in the data line. A two-dimensional image detector, wherein charge information is read to obtain the abnormal pixel information.
  7. 　請求項１から６のいずれかに記載の二次元画像検出器において、
    　前記異常画素情報を記憶する記憶手段を備え、
    　前記制御手段は、取得した異常画素情報を前記記憶手段に記憶させ、前記記憶手段に記憶させた異常画素情報に基づいて前記スイッチ駆動手段を操作することを特徴とする二次元画像検出器。     The two-dimensional image detector according to any one of claims 1 to 6,
    Storage means for storing the abnormal pixel information;
    The control means stores the acquired abnormal pixel information in the storage means, and operates the switch driving means based on the abnormal pixel information stored in the storage means.
  8. 　請求項１から７のいずれかに記載の二次元画像検出器において、
    　前記制御手段は、前記異常画素情報を定期的に取得することを特徴とする二次元画像検出器。     The two-dimensional image detector according to any one of claims 1 to 7,
    The two-dimensional image detector, wherein the control means periodically acquires the abnormal pixel information.
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