JP4655346B2 - X-ray equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an X-ray imaging apparatus for irradiating a subject with X-rays and imaging a transmitted X-ray image thereof.
[0002]
[Prior art]
  At present, imaging systems mainly used in X-ray imaging inspection are as follows.
[0003]
  1) Screen film photography combining intensifying screen (phosphor) and X-ray film
  2) Computed radiography using a plate (imaging plate) coated with a stimulable phosphor
  3) Photography using a combination of an image intensifier (II) that converts X-rays to light and a television (TV)
  However, in recent years, it has portability and high resolution characteristics such as the film / screen system and the imaging plate, and I.I. I. As a next-generation X-ray device having a real-time property of the TV system, a device using a thin film transistor (TFT) used for a liquid crystal display device or the like as a switching gate has been proposed. For this, a photodiode array is formed on the TFT panel, and an X-ray fluorescent plate is placed on the TFT array, and an image is read out, or a photoconductor material that directly converts X-rays into electric charges is used instead of the fluorescent plate. A method such as a technique of reading with a TFT panel has been proposed.
[0004]
  The first system includes a phosphor that converts X-rays into light on the X-ray detection surface, a photodiode array that converts the light into charges, a capacitor that accumulates charges, a TFT switch that reads charges, and the like.
[0005]
  The second system includes a photoconductor portion made of a semiconductor layer that directly converts X-rays into charges on the X-ray detection surface, a capacitor that accumulates charges, a TFT switch that reads charges, and the like.
[0006]
[Problems to be solved by the invention]
  However, in the X-ray imaging apparatus, the physical resolution of the imaging region is fixed to the pixel size constituted by individual TFTs, and if higher resolution is required, the pixel components including TFTs It is necessary to make it more precise. However, densification is limited by the capacity of the manufacturing process. In addition, since pixels formed by individual TFTs are in close contact with each other, crosstalk occurs between the pixels, and there is a problem that the actual resolution is lower than the physical resolution.
[0007]
[Means for Solving the Problems]
  The present invention employs the following means in order to solve the above problems..
[0008]
  Claim1According to the present invention, X-ray charge conversion means for converting transmitted X-rays from a subject into electric charge, two opposing electrodes for applying a voltage to each of the plurality of X-ray charge conversion means, and one of the electrodes And a charge accumulating unit for accumulating charges generated in the plurality of X-ray charge conversion units, and a charge reading unit for reading out the accumulated charges, respectively, facing the electrodes connected to the charge accumulating unit. The gist is that the other electrode is composed of a plurality of electrodes separated in the pixel.
[0009]
  According to the present invention, it is possible to improve the resolution of a necessary range in the imaging region without making all the elements constituting the pixel finer.
[0010]
  Claim2The invention of claim1In the present invention, voltage application to a plurality of electrodes is controlled in a time-sharing manner, and control for reading out each of the charges accumulated in the X-ray charge conversion means is performed in synchronization with the time-sharing timing.
[0011]
  According to the present invention, the resolution is improved without miniaturizing all the elements constituting the pixel, and the dark current of the X-ray charge conversion means corresponding to the electrode to which no voltage is applied is reduced, thereby improving the X-ray sensitivity. It becomes possible to make it.
[0012]
  Claim3The invention of claim1The position of the filter is movable with respect to the plurality of X-ray charge conversion means, and voltage application to a plurality of electrodes opposed to the electrode connected to the charge storage unit is performed corresponding to the position of the filter. The gist of the present invention is to control each of the charges stored in the X-ray charge conversion means while being controlled.
[0013]
  According to the present invention, the resolution is improved without miniaturizing all the elements constituting the pixel, the dark current of the X-ray charge conversion means corresponding to the electrode to which no voltage is applied is reduced, and the X-ray sensitivity is increased. Improve. Further, by avoiding unnecessary X-ray irradiation on the sensor to which no voltage is applied, the X-ray irradiation life of the X-ray charge conversion means can be improved.
[0014]
  Claim4Claims3The area of the filter X-ray passage hole corresponding to each of the plurality of electrodes facing the electrode connected to the charge storage unit is smaller than the area of each of the plurality of electrodes facing the electrode connected to the charge storage unit The gist is to have a passage area.
[0015]
  According to this invention, it becomes possible to irradiate X-rays in a range narrower than the area of each of the plurality of electrodes facing the electrode connected to the charge storage unit, and blocks the X-rays around each of the plurality of electrodes. Therefore, crosstalk between pixels formed by a plurality of electrodes is reduced, and resolution is improved.
[0016]
  Claim5Claims1, 2, 3, 4The X-ray charge conversion means is separately formed corresponding to a plurality of electrodes opposed to the electrodes connected to the charge storage portion in FIG.
[0017]
  According to the invention, the claims1, 2, 3, 4In, crosstalk between pixels is reduced and resolution is improved.
[0018]
  Claim6Claims3, 4In constructing a transmission X-ray image of a subject constituted by reading out the charges accumulated in the X-ray charge conversion means according to the position of the filter, from adjacent or plural X-ray charge conversion means The gist of the invention is to use an amount obtained by synthesizing the amount of electric charge to be read out for image construction.
[0019]
  According to the present invention, it is possible to construct an image having the same aspect ratio as that of the subject.
[0020]
  Claim7Claims2In constructing a transmission X-ray image of a subject formed by reading out the charges accumulated in the X-ray charge conversion means in synchronization with the time division timing, adjacent or plural X-ray charge conversion means The gist is to use an amount obtained by synthesizing the amount of charges read out more for image construction.
[0021]
  Claim8Claims1 to 7The X-ray charge conversion means is a photoconductor.
[0022]
  Claim9Claims1 to 7In,The gist of the X-ray charge conversion means is a phosphor and a photodiode.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0024]
  (Embodiment 1)
  FIG. 1 schematically shows a configuration of a part of an X-ray detector of the X-ray imaging apparatus according to the first embodiment.
[0025]
  In this X-ray detector, X-ray charge conversion means composed of a plurality of pixels is arranged in a matrix with a range surrounded by the gate lines 6 and readout lines 4 arranged in a grid as one pixel. Reference numeral 1 denotes a pixel electrode. Each pixel electrode 1 is connected to a charge storage unit 2 and a drain side of a TFT 3 as a charge readout means, a gate line 6 as a control line is connected to the gate of the TFT 3, and a readout line 4 is connected to the TFT 3. The source is connected. The TFT 3 is a thin film transistor and is composed of a field effect transistor. The gate line 6 is connected to a gate driver 7 as a control circuit unit, and the read line 4 is connected to a read circuit 5.
[0026]
  Although not explicitly shown in the figure, in order to distinguish the TFT 3, the pixel electrode 1, and the charge storage unit 1 by the pixel positions, a to d are applied to the gate line 6 a column, and vice versa. e to h, i to l for the gate line 6c column, and m to p for the gate line 6d column are added to the TFT 3, the pixel electrode 1, and the charge storage unit 1, respectively, and can be distinguished for each pixel. It was.
[0027]
  FIG. 2 shows a schematic diagram of a cross section corresponding to a single pixel of the X-ray detector. In FIG. 2, the plurality of X-ray charge conversion means are formed on the upper portion of the substrate 10 and are composed of the pixel electrode 1, the upper electrode 11 and the photoconductor 12. The photoconductor 12 is PbI₂Formed from (lead iodide)
. PbI₂A high potential is applied to the upper electrode 11 of the pixel electrode, and the pixel electrode is
An electric field is generated toward 1. PbI by X-ray exposure₂The negative charge generated inside
The positive charges are collected on the pixel electrode 1. In the pixel electrode 1, a charge accumulating portion 2 (capacitor) is composed of an electrode 13 connected to GND and an insulating layer 14, and accumulates the collected positive charges. The TFT 3 includes a gate electrode 15 connected to the gate line 6, a drain electrode 16 connected to the pixel electrode 1, a source electrode 17 connected to the readout line 4, and the like. The upper electrode 11 is configured as one common electrode as shown in FIG. 1 for each pixel arranged in a matrix.
[0028]
  FIG. 3 shows a schematic diagram of an equivalent circuit corresponding to a single pixel of the X-ray detector. The photoconductor 12 can be represented by a capacitor as shown in FIG. 3 and is connected to the capacitor forming the charge storage section 2. The photoelectric conversion unit 12 generates charges according to the incident X-rays by the X-ray exposure and accumulates them in the charge accumulation unit 2. In this state, when a voltage Vgs equal to or higher than the threshold voltage Vth is applied between the gate electrode 15 and the source electrode 17 constituting the TFT 3 via the gate line 6, the TFT 3 becomes conductive and is stored in the charge storage unit 2. The read charges are read out by the read circuit 5 including the amplifier 8 and the like via the read line 4.
[0029]
  Returning to FIG. 1, when the gate control signal Vgs from the gate driver 7 is applied to the gate line 6a after completion of the X-ray exposure, the TFTs 3a to 3d connected to the gate line 6a are all in a conductive state, and the X-ray exposure is performed. The charges stored in the charge storage units 2a to 2d according to the amount of radiation are read out to the read lines 4a to 4d, respectively. The read signal is amplified by amplifiers 8a to 8d included in the read circuit 5, and then converted from a parallel signal to a serial signal by a multiplexer 9, and input to an A / D converter (not shown). A digital image signal of one column corresponding to the charge amount of the pixel to be processed. By sequentially repeating the above operation from the gate line 6a to 6d, a two-dimensional X-ray image (still image) or X-ray fluoroscopic image (moving image) can be obtained.
[0030]
  4, the same reference numerals as those in FIG. 2 indicate the same components, and ap correspond to each pixel configured by the pixel electrode 1, the charge storage unit 2, and the TFT 3 in FIG. 1. Reference numeral 18 denotes a filter according to the present invention, which is made of lead and has a passage hole 19 for blocking X-rays. In the drawing, the filter 18 is illustrated as being separated from the upper electrode 11, but is actually configured to be in close contact. The passage hole 19 is formed corresponding to each pixel of a to p, and is formed smaller than each pixel, leaving the periphery of each pixel. The filter 18 is not shown in FIGS. 1 and 2 for ease of explanation.
[0031]
  The X-rays that have been exposed and passed through the subject pass through the filter only at the passage hole 19 as indicated by the arrow 20, and from the pixel electrode 1, the upper electrode 11, and the photoconductor 12 of the corresponding pixel. It is incident on the X-ray charge conversion means, and is read out as an image signal by the method already described. At this time, since the X-ray incidence is restricted by the filter 18 in the boundary region between the pixels, nonuniformity of the electric field generated between the upper electrode 11 and the pixel electrode 1 on the pixel boundary, and the optical conversion unit Crosstalk between pixels due to scattering of X-rays incident on 12 is reduced.
[0032]
  (Embodiment 2)
  FIG. 5 shows a second embodiment. In the figure, the same reference numerals as those in FIG. 4 denote the same components as those in the first FIG. Reference numeral 21 denotes a filter characteristic of the present embodiment. As shown by an arrow 24, the filter 21 is configured to be movable up and down in the drawing by a piezoelectric actuator, although not shown. The constituent elements 35 other than the filter 21 are the same constituent elements as those in the first embodiment described in FIGS. 1, 2, and 3, and the same reference numerals as those in FIGS. 1, 2, and 3 denote the same constituent elements. Indicates an element. In FIG. 5, the through holes 22 formed in the filter 21 correspond to the pixels a to p and are formed smaller than half of the pixel area, and the positions of the through holes for each pixel are the same in all the pixels. Arranged so that. That is, in FIG. 5, the lower half of each pixel, a2 to p2, is arranged at a position where X-rays are irradiated. When the X-rays are exposed, the transmitted X-rays are first exposed to the photoconductor 12 only in the region corresponding to the lower halves a2 to p2 of each pixel facing the passage hole of the filter 21 as indicated by an arrow 23. , And a charge is generated in the photoconductor 12 in accordance with the transmitted X-ray dose in the lower half region of each pixel. Thereafter, image data is acquired by the same operation as in the first embodiment. Next, the filter 21 is moved, and the passage hole 22 stops at a position corresponding to the upper half a1 to p1 of each pixel. Here, X-rays are again emitted, and image data is acquired in the same manner. Accordingly, in the second embodiment, the size of one pixel composed of the pixel electrode 1, the charge storage unit 2, the TFT 3, and the like is the same as that in the first embodiment, but the filter 21 is moved to transmit each pixel. By dividing the X-ray irradiation area into upper and lower halves and acquiring image data in a time-division manner, it becomes possible to image the image with a resolution doubled vertically in the figure.
[0033]
  In this embodiment, the pixels a to p are square pixels whose aspect ratio and aspect ratio are approximately 1: 1, but the image data obtained by this embodiment is approximately 2: 1. Thus, for example, image data at an intermediate position is constituted by an average value of a1 and e1 pixel data, and the image is reconstructed so that the aspect ratio is approximately 1: 1.
[0034]
  In the present invention, the filter 21 is driven by a piezoelectric actuator. However, the present invention is not based on such a driving method, and may be driven using, for example, an encoder and a servo motor.
[0035]
  (Embodiment 3)
  The third embodiment is shown in FIGS. In the figure, the same reference numerals as those in FIGS. 1, 2, 3, and 4 denote the same components as those in the first embodiment. 6, 7, and 8, the feature of this embodiment is that the upper electrode 11 in the first embodiment is separated into pixels to form the upper electrode 25. Further, as shown in FIGS. 6 and 7, in this embodiment, the upper electrodes 25a and 25b are formed by dividing the upper and lower halves of each pixel in the figure in parallel with the readout line 4 for each pixel. Formed. In FIG. 7, when the switch 26 is turned on, a voltage is applied to the upper electrode 25a connected to the switch 26, an electric field is generated between the upper electrode 25a and the pixel electrode 1, and when the switch 27 is turned on, the upper electrode A voltage is applied to 25b, and an electric field is generated between the pixel electrode 1 and the voltage. Therefore, first, X-rays are emitted from the direction of the arrow 28 shown in FIG. 6 with the switch 26 turned on and the switch 27 turned off, and image data is acquired by the same operation as in the first embodiment. Next, X-rays are emitted with the switch 27 turned on and the switch 26 turned off to acquire image data.
[0036]
  As described above, as in the second embodiment, the size of one pixel including the pixel electrode 1, the charge storage unit 2, the TFT 3, and the like is the same as that in the first embodiment, but the upper electrodes 25a and 25b are connected. Is applied in a time-sharing manner, X-rays are respectively emitted, and image data is acquired, so that the image can be imaged twice in the vertical direction on the figure in a pseudo manner.
[0037]
  Further, the electrodes 25a and 25b are divided into the area of the upper electrode 11 corresponding to the size of one pixel, and one applied voltage is controlled off, so that the dark current per pixel in the first embodiment is reduced. In addition, the sensitivity to X-rays per pixel corresponding to the divided electrode 25a or 25b was improved.
[0038]
  In this example, the vertical and horizontal ratios of the pixels a to p are square pixels as in the second embodiment, but the image data obtained by this example is as follows. Approximately 2: 1. Thus, for example, image data at an intermediate position is constituted by an average value of a1 and e1 pixel data, and the image is reconstructed so that the aspect ratio is approximately 1: 1.
[0039]
  In this embodiment, the upper electrode 25 is divided into two divided into upper electrodes 25a and 25b for each pixel in parallel with the readout line. However, the present invention does not depend on the dividing direction or the number of divisions. Of course, they may be separated in parallel and the number of divisions may be three or more. Further, in this embodiment, the X-ray irradiation is set to the timing of exposure in synchronism with the time-division voltage application to the upper electrodes 25a and 25b, but the present invention is the voltage application timing to the divided upper electrodes, For example, during continuous X-ray irradiation, voltage application to the upper electrode 25a and reading of image data may be performed, and subsequently voltage application to the upper electrode 25b and reading of image data may be performed. In addition, the upper electrode division for each pixel is divided into two, and the upper electrodes to be applied simultaneously using a switch are divided into two groups. However, the present invention is not based on such a voltage application method. May be sequentially applied to acquire image data, or only the imaging region requiring high resolution may be divided and may not be divided.
[0040]
  (Embodiment 4)
  FIG. 9 shows a fourth embodiment. The fourth embodiment is characterized in that the filter 21 of the second embodiment and the third embodiment are combined. In the figure, the same reference numerals as those in FIGS. 5 and 6 are the same constituent elements as those in the second and third embodiments, respectively.
[0041]
  In FIG. 9, the filter 21 is configured to be movable up and down in the drawing by a piezoelectric actuator, although not shown, as indicated by an arrow 28. The through holes 22 formed in the filter 21 correspond to the pixels a to p, are formed to be smaller than half of the pixel area, and are formed so that the positions of the through holes for each pixel are the same in all the pixels. The That is, in FIG. 9, the lower half of each pixel, a2 to p2, is arranged at a position where X-rays are irradiated. As in the third embodiment, X-rays are emitted from the direction of the arrow 28 shown in FIG. 6 with the switch 26 turned on and 27 turned off, and the image data is operated in the same manner as in the first embodiment. To get. Next, the filter 21 is moved, the passage hole 22 is stopped at a position corresponding to the pixels a1 to p1, X-rays are emitted with the switch 27 turned on and the switch 26 turned off, and image data is acquired. In this embodiment, the pixels a to p are square pixels whose aspect ratio and aspect ratio are approximately 1: 1, but the image data obtained by this embodiment is approximately 1: 2. Therefore, for example, image data at an intermediate position is constituted by an average value of a1 and e1 pixel data, and reconstructed so that the aspect ratio is approximately 1: 1.
[0042]
  As described above, as in the second or third embodiment, the size of one pixel including the pixel electrode 1, the charge storage unit 2, the TFT 3, and the like is the same as that in the first embodiment, but the movement of the filter 21 At the same time, voltage is applied to the upper electrodes 25a and 25b in a time-sharing manner, and each is irradiated with X-rays to acquire image data. Is possible. Further, the electrodes 25a and 25b are divided into the area of the upper electrode 11 corresponding to the size of one pixel, and one applied voltage is controlled off, so that the dark current per pixel in the first embodiment is reduced. In addition, the sensitivity to X-rays per divided pixel corresponding to the divided electrode 25 is improved, and in the third embodiment, the electric field distribution between the divided upper electrode 25 and the pixel electrode 1 is applied to the upper electrode 25. Depending on the method, the electric field distribution differs, and in particular in the direction perpendicular to the divided direction of the upper electrode 25, that is, in the direction parallel to the gate line 6 in FIG. 7, with respect to the upper electrode 25a or 25b corresponding to one pixel. An electric field is generated between the pixel electrodes 1 and crosstalk occurs. In this embodiment, X-ray irradiation is blocked by the filter 21 for the divided pixels from which no image is acquired. To, reduce crosstalk, the effect of improving the resolution. Further, by preventing unnecessary X-ray irradiation to the photoconductor 12 by the filter 21, there is an effect of reducing the deterioration of the photoconductor 12 due to X-ray irradiation and extending the life. Further, as shown in 28 of FIG. 9, the size of the passage hole 22 of the filter 21 is formed smaller than the divided electrode 25a corresponding to the divided pixel P2 of the pixel P, for example, so that it is other than the corresponding pixel of the X-ray. The resolution was further improved by reducing the amount of irradiation and reducing crosstalk.
[0043]
  As in the second embodiment, the filter 21 is driven by a piezoelectric actuator in the present invention. However, the present invention is not based on such a driving method, and may be driven using, for example, an encoder and a servo motor. Of course. In addition, the upper electrode 25 is divided in two into the upper electrodes 25a and 25b for each pixel in parallel with the readout line. However, the present invention does not depend on the division direction or the number of divisions. For example, the upper electrode 25 is separated in parallel with the gate line. Of course, the number of divisions may be three or more. In addition, although the X-ray irradiation is performed by controlling the time-division voltage application to the upper electrodes 25a and 25b in accordance with the position of the filter 21, the present invention is adapted to apply the voltage to the divided upper electrodes. For example, during continuous X-ray irradiation, voltage application to the upper electrode 25a and reading of image data, and subsequent movement of the filter 21, followed by voltage application to the upper electrode 25b are not based on timing or X-ray irradiation timing. And image data may be read out. Further, in this embodiment, the upper electrode division for each pixel is divided into two, and the upper electrode applied simultaneously using a switch is divided into two groups, but the present invention is not based on such a voltage application method, For example, the image data may be acquired by sequentially applying a voltage to each divided electrode.
[0044]
  (Embodiment 5)
  FIG. 10 shows the fifth embodiment. In the fifth embodiment, corresponding to the upper electrodes 25a and 25b divided in the third and fourth embodiments, X charge conversion means are separately formed to be 29a and 29b. Other configurations are all the same as those in the third and fourth embodiments. As shown in the fourth embodiment, the electric field distribution of the divided upper electrode 25 and the pixel electrode 1 becomes different electric field distribution according to the voltage application method to the upper electrode 25, and in particular, the direction in which the upper electrode 25 is divided. In the vertical direction, that is, in the direction parallel to the gate line in FIG. 7, an electric field is generated between the plurality of pixel electrodes 1 with respect to the upper electrode 25a or 25b corresponding to one pixel, and crosstalk occurs. However, according to the present embodiment, the crosstalk can be almost eliminated and the resolution can be improved.
[0045]
  (Embodiment 6)
  FIG. 11 and FIG. 12 show a sixth embodiment. The sixth embodiment is characterized in that the plurality of photoconductors in the first, second, third, and fourth embodiments constitute an X-ray fluorescent plate on the photoelectric conversion element. In the figure, the same reference numerals as those in FIGS. 2 and 3 denote the same components as those in the first embodiment. In FIG. 11, reference numeral 31 denotes a photodiode configured for each pixel, and reference numeral 30 denotes a charge storage unit based on the electrostatic capacitance component of the photodiode 31.
[0046]
  Reference numeral 3 denotes a TFT 3 as a first switch unit, 5 denotes a readout circuit, and 9 denotes an amplifier constituting a part of the readout circuit.
[0047]
  When the TFT 3 is turned on before X-ray exposure and a reverse bias is applied to the photodiode 31, positive charge is accumulated on the cathode side of the photodiode and negative charge on the anode side. When the TFT 3 is exposed to X-rays by the gate line 6 in a non-conductive state, the photodiode 31 generates charges according to the amount of X-ray irradiation, and cancels the charges accumulated in the charge accumulation unit 30. Here, the TFT 3 is again turned on to be charged again by the reverse bias. This charged charge is read out by the amplifier 9 constituting the reading circuit 5.
[0048]
  FIG. 12 is a schematic cross-sectional view of a single pixel of the X-ray detector in the sixth embodiment. 33 is a phosphor that converts X-rays into light.₂O₂S and converted into light according to the amount of X-ray exposure in the pixel.
[0049]
  Reference numeral 31 denotes a photodiode, which generates an electric charge according to the amount of incident light converted by X-rays in the pixel. Reference numeral 32 denotes an upper electrode, which applies a reverse bias to the photodiode 32 as shown in FIG. The upper electrode 32 corresponds to the upper electrodes 11 and 25 of the first, second, third, and fourth embodiments. Therefore, although the configuration of the photoconductor is different, the subsequent configuration requirements are the same as in the first, second, third, and fourth embodiments except for the control voltage of the gate line 6, the direction of the current flowing through the readout line 4, etc. However, the same configuration as in the first, second, third, and fourth embodiments is possible.
[0050]
  In this embodiment, Gd is used as the phosphor.₂O₂S was used, but CdWo_FourOf course, any of phosphors such as CsI and BaFCl may be used.
[0051]
【The invention's effect】
  According to the invention shown in the first embodiment, it is possible to allow X-rays to pass through only holes smaller than the physical pixel size, enter the individual X-ray charge conversion means, and block X-rays around the pixels. , Crosstalk between pixels is reduced and resolution is improved.
[0052]
  According to the invention shown in the second embodiment, the resolution is improved without miniaturizing the elements constituting the pixel. In addition, when constructing a transmission X-ray image of a subject, the amount of the charge read by the adjacent or peripheral X-ray charge conversion means is used in the image composition, so that the aspect ratio and aspect ratio of the subject can be increased. Can be constructed.
[0053]
  According to the invention shown in the third embodiment, by refining only the upper electrode, it is possible to improve the resolution of a necessary range in the imaging region without refining all elements constituting the pixel, The dark current of the X-ray charge conversion means corresponding to the electrode to which no voltage is applied can be reduced, and the X-ray sensitivity can be improved.
[0054]
  According to the invention shown in the fourth embodiment, the resolution is improved without reducing all the elements constituting the pixel, and the dark current of the X-ray charge conversion means corresponding to the electrode to which no voltage is applied is reduced. , Improve X-ray sensitivity. Further, by avoiding unnecessary X-ray irradiation to a sensor to which no voltage is applied, crosstalk is reduced, resolution is improved, and the X-ray irradiation lifetime of the X-ray charge conversion means is improved.
[0055]
  According to the invention shown in the fifth embodiment, in particular, the crosstalk generated in the direction perpendicular to the divided direction of the upper electrode can be substantially eliminated, and the resolution can be improved.
[0056]
  According to the invention shown in the sixth embodiment, the plurality of X-ray charge conversion means in the first, second, third, and fourth embodiments can be configured by an X-ray fluorescent plate on the photoelectric conversion element.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a part of an X-ray detector according to Embodiment 1 of the present invention.
FIG. 2 is a schematic cross-sectional view corresponding to a single pixel of the X-ray detector according to the first embodiment of the present invention.
FIG. 3 is an equivalent circuit schematic diagram corresponding to a single pixel of the X-ray detector according to the first embodiment of the present invention.
FIG. 4 is a schematic diagram of the entire configuration of an X-ray detector according to Embodiment 1 of the present invention.
FIG. 5 is a schematic diagram of the entire configuration of an X-ray detector according to Embodiment 2 of the present invention.
FIG. 6 is a schematic diagram of the entire configuration of an X-ray detector according to Embodiment 3 of the present invention.
FIG. 7 is a schematic configuration diagram of a part of an X-ray detector according to Embodiment 3 of the present invention.
FIG. 8 is a schematic cross-sectional view corresponding to a single pixel of an X-ray detector according to Embodiment 3 of the present invention.
FIG. 9 is a schematic diagram of the entire configuration of an X-ray detector according to Embodiment 4 of the present invention.
10 is a schematic cross-sectional view corresponding to an X-ray detector single pixel in Embodiment 5 of the present invention. FIG.
FIG. 11 is an equivalent circuit schematic diagram corresponding to an X-ray detector single pixel according to Embodiment 6 of the present invention;
12 is a schematic cross-sectional view corresponding to a single pixel of an X-ray detector in Embodiment 6 of the present invention. FIG.
[Explanation of symbols]
  1 Pixel electrode
  2 Charge storage unit
  3 TFT
  4 Read line
  5 Reading circuit
  6 Gate line
  7 Gate driver
  8 Amplifier
  10 Substrate
  11 Upper electrode
  12 Photoelectric converter
  18 Filter
  19 Passing hole
  21 Filter
  22 Passing hole
  25a Upper electrode
  25b Upper electrode
  30 Charge storage unit
  31 photodiode
  33 Phosphor

Claims (9)

  A plurality of X-ray charge conversion means for converting transmitted X-rays from the subject into charges, two opposing electrodes for applying a voltage to each of the plurality of X-ray charge conversion means, and one of the electrodes connected The charge storage means for storing the charges generated in the plurality of X-ray charge conversion means and the charge reading means for reading out the stored charges, respectively, and the other facing the electrode connected to the charge storage section An X-ray imaging apparatus comprising: a plurality of electrodes separated in a pixel. With the voltage applied to the plurality of electrodes is controlled in time division, time synchronization with the division timing, according to claim 1, characterized in that each read control the charge accumulated in the X-ray charge conversion means X-ray imaging device. The position of the filter is movable with respect to the plurality of X-ray charge conversion means, and voltage application to the plurality of electrodes opposed to the electrode connected to the charge storage unit is controlled according to the position of the filter. Rutotomoni, X-rays imaging apparatus according to claim 1, characterized in that each read control the charges accumulated in the X-ray charge conversion means. The area of the X-ray passage hole corresponding to each of the plurality of electrodes facing the electrode connected to the charge storage unit is smaller than the area of each of the plurality of electrodes facing the electrode connected to the charge storage unit The X-ray imaging apparatus according to claim 3, further comprising: Corresponding to the plurality of electrodes opposite to the electrode connected to the charge storage unit, according to any one of claims 1, 2, 3, 4, characterized in that separate form an X-ray charge conversion means X-ray imaging device. Depending on the position of the filter, when constructing a transmission X-ray image of a subject constituted by reading out each of the charges accumulated in the X-ray charge conversion means, it is read out by an adjacent or plural X-ray charge conversion means. The X-ray imaging apparatus according to claim 3 or 4 , wherein an amount obtained by synthesizing the charge amount is used for an image configuration. In synchronism with the time division timing, each of the charges accumulated in the X-ray charge conversion means is read out, and when a transmission X-ray image of the subject is formed, it is read out from an adjacent or a plurality of X-ray charge conversion means. The X-ray imaging apparatus according to claim 2 , wherein an amount obtained by synthesizing the charge amount is used for image construction. X-ray imaging apparatus according to any one of claims 1, wherein the plurality of X-ray charge conversion means is a photoconductive member 7. The X-ray imaging apparatus according to any one of claims 1 to 7 , wherein the plurality of X-ray charge conversion means are a phosphor and a photodiode.

Images