Radiation imaging devices and radiation imaging systems

Abstract

This invention relates to a radiation imaging apparatus and a radiation imaging system. The radiation imaging apparatus includes: a pixel; a driver that controls the pixel via a drive line; a readout circuit that reads signals from the pixel via column signal lines; and a detector that detects radiation exposure information separately from a radiation image. Each of the column signal lines is connected to pixels arranged in two pixel columns. The pixel includes a first pixel and a second pixel with different sensitivities. The first pixel and the second pixel are connected to a common column signal line and to different drive lines. When detecting the radiation exposure information, the driver drives the first pixel and the second pixel at different timings, and the detection circuit detects the radiation exposure information based on signals output from the first pixel and the second pixel.

Description

Technical Field

[0001] This invention relates to a radiation imaging device and a radiation imaging system. Background Technology

[0002] Radiation imaging devices using flat panel displays (FPDs) connected to a sensor board with drive and readout circuits are widely used. These drive and readout circuits are configured to drive pixels or read out signals. The sensor board includes multiple pixels configured to convert incident radiation into electrical signals and arranged in a two-dimensional matrix. Because analog amplifiers, analog-to-digital (A / D) converters, and other components are integrated at high density, the readout circuits are expensive and constitute a large proportion of the component cost of radiation imaging devices. Japanese Patent No. 2021-078050 discloses a method that allows two adjacent pixels to share a single signal line to output signals, thereby reducing the circuit size of the readout circuit connected to the signal line. Summary of the Invention

[0003] As part of the multiple functions of a radiation imaging device, it detects the start or end of radiation exposure by detecting the radiation information entering the device, and performs automatic exposure control (AEC) by detecting the dose of incident radiation. Accurate detection of radiation exposure information is necessary for accurately detecting radiation exposure or radiation dose.

[0004] Several embodiments of the present invention provide a technique that improves the detection accuracy of illumination information while reducing the circuit size of the readout circuit.

[0005] According to some embodiments, a radiation imaging device is provided, the radiation imaging device comprising: a plurality of pixels arranged to form a plurality of rows and a plurality of columns; a driving circuit configured to control the plurality of pixels via a plurality of driving lines extending along a row direction; a readout circuit configured to read signals generated by the plurality of pixels via a plurality of column signal lines; and a detection circuit configured to detect radiation exposure information and radiation images separately based on the signals read by the readout circuit, wherein each of the plurality of column signal lines is connected to a pixel arranged in two adjacent pixel columns along the row direction, the plurality of pixels including a first pixel and a second pixel with different sensitivities to radiation, the first pixel and the second pixel being connected to a common column signal line among the plurality of column signal lines and to different driving lines among the plurality of driving signal lines, and when detecting the radiation exposure information, the driving circuit is configured to drive the first pixel and the second pixel at different timings, and the detection circuit is configured to detect the radiation exposure information based on signals output from the first pixel and signals output from the second pixel.

[0006] Other features of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0007] Figures 1A to 1C This is a diagram illustrating an example configuration of a radiation imaging apparatus according to an embodiment;

[0008] Figures 2A to 2C It is shown Figure 1A A diagram illustrating an example of the pixel configuration of a radiation camera device;

[0009] Figure 3 It is shown Figure 1A A timing diagram illustrating an operational example of the radiation camera device shown;

[0010] Figure 4 It is shown Figure 1A A diagram showing a variant of the radiation camera device;

[0011] Figure 5 It is shown Figure 4 A timing diagram illustrating an operational example of the radiation camera device shown;

[0012] Figure 6 It is shown Figure 4 A diagram illustrating a calibration example of the radiation imaging device shown; and

[0013] Figure 7 It shows the use Figures 1A to 1C and Figure 4 The diagram shows an example configuration of a radiation camera system for a radiation camera device. Detailed Implementation

[0014] In the following, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are not intended to limit the scope of the claimed invention. Multiple features are described in the embodiments, but the invention is not limited to requiring all such features, and multiple such features may be combined as appropriate. Furthermore, in the drawings, the same or similar configurations are given the same reference numerals, and redundant descriptions thereof are omitted.

[0015] The radiation according to the invention can include not only alpha rays, beta rays, and gamma rays generated by light beams of particles (including photons) emitted through radioactive decay, but also light beams of equal or greater energy, such as X-rays, particle rays, and cosmic rays.

[0016] The following will refer to Figures 1A to 7 A radiation imaging apparatus according to an embodiment of the present disclosure is described. Figure 1A This is an equivalent circuit diagram illustrating configuration examples of a radiation imaging apparatus 100 according to several embodiments of the present disclosure. The radiation imaging apparatus 100 includes a plurality of pixels 1 arranged to form a plurality of rows and columns, a driving circuit 10, a reading circuit 12, a detection circuit 13, and a power supply circuit 11. Hereinafter, to indicate a particular one of the plurality of pixels 1, a suffix, such as pixel 1 "a", is added after the reference numerals. If no special distinction is required, it is simply referred to as "pixel 1". This also applies to other components.

[0017] Drive circuit 10 via along the row direction ( Figure 1A Multiple drive lines 6 extending horizontally (in the middle) control multiple pixels 1. The drive circuit 10 includes shift circuits, etc., and sequentially causes multiple pixels 1 to output signals via the multiple drive lines 6 according to a start signal or clock signal transmitted from the control circuit (not shown).

[0018] The readout circuit 12 reads signals generated by multiple pixels 1 via multiple column signal lines 3. More specifically, the readout circuit 12 reads signals from pixels 1 driven by the driving circuit 10 via driving lines 6. The readout circuit 12 includes an amplifier circuit 9, a multiplexer MUX, and an analog-to-digital converter (ADC). The readout circuit 12 performs analog-to-digital conversion on the signals generated by pixels 1 and sequentially transmits digital signals to the detection circuit 13 according to the analog signals generated by pixels 1. In this embodiment, each of the multiple column signal lines 3 is connected to pixels 1 arranged in two adjacent pixel columns along the row direction. If a column signal line 3 is shared by two pixel columns, the number of amplifier circuits 9 and the circuit size of the multiplexer MUX in the readout circuit 12 are reduced. Therefore, the circuit size of the readout circuit 12 can be reduced in the radiographic imaging device 100.

[0019] The detection circuit 13 detects radiation exposure information and radiation images separately based on the signals read by the reading circuit 12. The radiation exposure information, distinct from the radiation image, may include information indicating the start or end of radiation exposure and information about the incident radiation dose. If the detection circuit 13 detects radiation exposure information, the radiation imaging device 100 may include an automatic exposure control (AEC) function. The detection of exposure information can be performed, for example, by an arithmetic circuit 2 of the detection circuit 13. For example, the arithmetic circuit 2 may be configured to include a processor such as a CPU. The operation of the detection circuit 13 can be performed if the processor of the arithmetic circuit 2 executes a program stored in a storage circuit 7 such as RAM or ROM. The arithmetic circuit 2 may be formed by a dedicated circuit such as an application-specific integrated circuit (ASIC). Additionally, the detection circuit 13 may generate data for the radiation image based on signals output from multiple pixels 1. The radiation image data can be transmitted to a monitor outside the radiation imaging device 100 and displayed on the monitor as the captured radiation image.

[0020] The power supply circuit 11 supplies power to components in the radiation imaging device 100, such as the drive circuit 10, the readout circuit 12, and the detection circuit 13. Additionally, the power supply circuit 11 supplies a bias voltage to the pixel 1 via the bias line 8, which the pixel 1 uses to convert incident radiation into a charge signal.

[0021] exist Figure 1AThe configuration shown depicts 4 rows × 6 columns of pixels 1. However, the invention is not limited to this, and more pixels 1 can be arranged in the radiation imaging device 100. The plurality of pixels 1 includes pixels 1a and 1b that allow the detection circuit 13 to separately detect radiation exposure information from the radiation image. Pixels 1a and 1b have different sensitivities to radiation. Here, it will be assumed that pixel 1a has a higher sensitivity to radiation than pixel 1b. Pixels 1a and 1b are connected to a common column signal line 3a among the plurality of column signal lines 3, and are respectively connected to different drive lines 6a and 6b among the plurality of drive lines 6. For example, the detection circuit 13 will be described in detail later, based on the signals output from pixel 1a and the signals output from pixel 1b, to separately detect radiation exposure information, such as the start of radiation exposure, the end of radiation exposure, and the incident radiation dose, from the radiation image to perform AEC.

[0022] like Figure 1A As shown, each pixel 1 includes: a conversion element 20 configured to convert radiation into electrical charge; and a switching element 21 configured to output a signal based on the converted charge to a column signal line 3. The column signal line 3 may be arranged near the conversion element 20 of pixel 1. For this reason, a non-negligible parasitic capacitance is formed between the column signal line 3 and the electrodes of the conversion element 20, and crosstalk occurs, transferring the charge of the conversion element 20 of pixel 1 to the column signal line 3 via the parasitic capacitance.

[0023] When the signal used to obtain illumination information from pixel 1a is read, charge is accumulated in the electrodes of the conversion element 20 of pixel 1 by the incident radiation, and the signal derived from crosstalk is transmitted to column signal line 3a via parasitic capacitance. Similarly, when the signal used to obtain illumination information from pixel 1b is read, the signal derived from crosstalk is transmitted to column signal line 3a via parasitic capacitance. The two signals derived from crosstalk are signals for the same column signal line 3a, and therefore have substantially the same quantity. Therefore, by obtaining the difference between the signal output from pixel 1a and the signal output from pixel 1b, the component derived from crosstalk can be suppressed in the signal output from pixel 1a. That is, the accuracy of the detection circuit 13 in detecting illumination information is improved. Therefore, in the radiation imaging device 100, the accuracy of performing functions such as AEC using illumination information is improved.

[0024] Furthermore, the signal read from pixel 1 may include an offset component derived from elements such as transistors in the amplification circuit 9 arranged in the readout circuit 12. The characteristics of the offset component may vary due to temperature changes during operation or the operating environment. On the other hand, since pixels 1a and 1b are used to allow the detection circuit 13 to detect illumination information read from the same column signal line 3a, the influence of the offset component can be reduced by obtaining the difference between the signal output from pixel 1a and the signal output from pixel 1b. Therefore, the accuracy of the detection circuit 13 in detecting illumination information for AEC functions is improved, thereby improving the accuracy of performing functions such as AEC using illumination information in the radiation imaging device 100.

[0025] exist Figure 1A In the configuration shown, among multiple pixels 1, two pixels 1 that are adjacent to each other along the row direction and connected to the common column signal line 3 have a symmetrical configuration across the common column signal line 3 (details are in...). Figure 2A (As shown in the diagram). A symmetrical point can be, for example, a line connecting the geometric centroids of electrodes (e.g., electrode 111 or electrode 115, described later) disposed in the conversion element 20 of two pixels 1 along the column direction of the column signal line 3. Figure 1A The intersection point between the center lines (vertical direction) in the middle. In this embodiment, as... Figure 1A As shown, pixels 1a and 1b, used for detecting illumination information, are arranged in the same row and have a symmetrical relationship across the common column signal line 3a. Therefore, if misalignment or the like occurs when forming the switching element 21, the signal output from pixel 1a and the signal output from pixel 1b may include different offset components. In this case, offset data obtained without radiation irradiation is stored in advance in the storage circuit 7, thereby reducing the offset components caused by misalignment.

[0026] If pixels 1a and 1b, used to separately detect radiation exposure information from radiation images, are connected to a common column signal line 3a, then pixels 1a and 1b do not always need to be adjacent to each other along the row direction. For example, as Figure 1B As shown, pixel 1a and pixel 1b can be arranged in the same column. If the pixels have Figure 1B The configuration shown above has the same characteristics as pixels 1a and 1b. Figure 1A Compared to the symmetrical point configuration shown, the offset components derived from misalignment are essentially the same. Therefore, the influence of the offset components derived from misalignment can only be suppressed by obtaining the difference between the signal output from pixel 1a and the signal output from pixel 1b.

[0027] Additionally, for example, such as Figure 1CAs shown, pixels 1a and 1b can be arranged in different rows and columns. As mentioned above, the arrangement of pixels 1a and 1b used for detecting illumination information is not limited to this embodiment, and the number or position of pixels 1a and 1b can also be changed. For example, a combination of pixels 1a and 1b can be arranged in a specific row at predetermined intervals.

[0028] In the pixel row where pixels 1a and 1b are arranged (hereinafter sometimes referred to as the AEC row), the number of pixels 1 used for the radiation image is smaller than in other pixel rows. When generating the radiation image, the output values ​​of pixels 1 surrounding the AEC row are needed to correct or interpolate the signals of pixels 1a and 1b used for the image. Furthermore, in the pixels 1 arranged on the AEC row, signals are repeatedly read from pixels 1a and 1b during radiation exposure. Therefore, even for pixels 1 arranged on the AEC row, it may be necessary to use the output values ​​of pixels 1 surrounding the AEC row for correction or interpolation. That is, a radiation image can be generated based on the signals output from pixels 1 arranged on rows other than the pixel rows containing pixels 1a and 1b. Figure 1A In the configuration shown, an AEC row is formed corresponding to the arrangement of pixels 1a and 1b. Figure 1B and Figure 1C In the configuration shown, two AEC rows are formed. Therefore, since only one AEC row needs correction or interpolation, in Figure 1A The structure shown has higher correction accuracy when generating radiographic images.

[0029] In addition, Figure 1A In the configuration shown, since pixels 1a and 1b are arranged adjacent to each other, the dose of incident radiation is essentially the same. For this reason, since the aforementioned crosstalk amount also becomes essentially the same, signals derived from crosstalk and superimposed on the signals output from pixels 1a and 1b can be accurately suppressed. For example, in Figure 1B and Figure 1C In the arrangement shown, the number of pixel rows arranged between the pixel row containing pixel 1a and the pixel row containing pixel 1b can be 10 or less, or 5 or less. Additionally, pixel 1a and pixel 1b can be arranged in adjacent rows.

[0030] Figure 2A This is a plan view showing an example configuration of pixels 1a and 1b according to this embodiment. Figure 2B and Figure 2C They are along Figure 2A The cross-sectional views taken by lines A-A' and B-B'. Among the multiple pixels 1, pixels other than pixels 1a and 1b can have the same structure as pixel 1a. Figure 2A In the configuration shown, two pixels 1a and 1b, adjacent to each other along the row direction and connected to a common column signal line 3a, have a point-symmetric configuration across the common column signal line 3a. However, the invention is not limited to this. For example, pixels 1a and 1b can have a line-symmetric configuration across the common column signal line 3a. To achieve this line-symmetric relationship between pixels 1a and 1b, for example, the switching element 21 can be arranged at the center along the column direction. This also applies to other pixels 1 adjacent to each other along the row direction and connected to the common column signal line 3. In this case, the axis of symmetry can be the center line of the column signal line 3 along the column direction.

[0031] In this embodiment, Figure 2B and Figure 2C A scintillator (not shown) that generates light based on incident radiation is also provided on the upper side of the cross-sectional view. The scintillator is arranged to cover a plurality of pixels 1. The light converted by the scintillator is converted into charge by the conversion element 20 and transmitted to the column signal line 3 via the switching element 21. That is, the pixel 1 according to this embodiment is an indirect type element that includes a scintillator that converts radiation into light that can be detected by the conversion element 20. However, a direct type conversion element 20 that directly converts radiation into charge can also be used in the pixel 1.

[0032] like Figures 2A to 2C As shown, in pixels 1a and 1b, a switching element 20, a switching element 21, and wiring patterns such as column signal lines 3a, drive lines 6a and 6b, and bias lines 8 are arranged. In this embodiment, a PIN diode is used as the switching element 20, and the switching element 20 includes an electrode 111, a dopant semiconductor layer 112, a semiconductor layer 113, a dopant semiconductor layer 114, an electrode 115, and a protective layer 116. In this embodiment, a thin-film transistor (TFT) is used as the switching element 21, and the switching element 21 includes a control electrode 101, a main electrode 105 (the source in this embodiment), a main electrode 106 (the drain in this embodiment), an insulating layer 102, a semiconductor layer 103, and a dopant semiconductor layer 104.

[0033] The upper electrode of the switching element 20 is connected to the bias line 8, which is configured to apply a predetermined bias voltage. The electrode 111 of the switching element 20 is connected to the main electrode 106 of the switching element 21. The control electrode 101 of the switching element 21 is connected to drive lines 6a and 6b, and the conducting / non-conducting state of the switching element 21 is controlled by signals supplied from the drive circuit 10 to drive lines 6a and 6b. The main electrode 105 of the switching element 21 is connected to the column signal line 3a. If the switching element 21 becomes conductive, the charge in the switching element 20 is transmitted as an electrical signal to the column signal line 3a.

[0034] As Figures 2A to 2C The difference between pixel 1a and pixel 1b shown is that pixel 1a does not have a light-shielding layer 22, while pixel 1b has a light-shielding layer 22. Figure 2C As shown, the light-shielding layer 22 is formed using the bias line 8. The light-shielding layer 22 serves to shield the light converted by the scintillator, and the conversion element 20 is sensitive to the light-shielding layer 22. Therefore, the light-shielding layer 22 is arranged between the pixel 1b and the scintillator. If the bias line 8 is made of a metal that shields the light generated by the scintillator, the width of the bias line 8 is increased to cover the entire surface of the conversion element 20 of the pixel 1b. This makes it possible to form a pixel 1b with a lower radiation sensitivity than pixel 1a without increasing the number of processes. The entire surface of the conversion element 20 is covered to suppress light leakage. However, the invention is not limited to this, and any configuration can be adopted if the radiation sensitivity between pixel 1a and pixel 1b is changed. For example, the light-shielding layer 22 can be a different metal layer than the bias line 8, or a portion of the conversion element 20 of the pixel 1b may not be covered by the light-shielding layer 22. Alternatively, for example, as a light-shielding layer, a colored (e.g., black) resin can be arranged between the protective layer 116 and the scintillator to cover the conversion element 20 of the pixel 1b. In addition, if the conversion element 20 is a direct conversion element, the conversion element 20 of pixel 1b can be covered by a shielding member made of lead or tungsten, making it difficult for radiation to enter the conversion element 20 of pixel 1b.

[0035] As described above, a parasitic capacitance is formed between the electrode 111 of the conversion element 20 and the column signal line 3 (main electrode 105), which are spatially connected to each other. Through this parasitic capacitance, the electrode 111 of the conversion element 20 and the column signal line 3 are capacitively coupled, resulting in crosstalk. Since signals derived from this crosstalk are written from all pixels 1 connected to the column signal line 3, the signal volume is enormous. Therefore, it is difficult to correctly read the signal output from the pixel 1a connected to the column signal line 3a.

[0036] Figure 3This is a timing diagram showing the operation of the radiation imaging device 100 when the detection circuit 13 detects radiation information separately from the radiation image. "Vg1" indicates the signal Vg1 input to the drive line 6a to drive pixel 1a. When signal Vg1 is activated (H), the switching element 21 of pixel 1a is driven and becomes conductive, thus reading the signal from pixel 1a. "Vg2" indicates the signal Vg2 input to the drive line 6b to drive pixel 1b. When signal Vg2 is activated (H), the switching element 21 of pixel 1b is driven and becomes conductive, thus reading the signal from pixel 1b. "SH" indicates a sample-and-hold operation. When signal SH is activated (H), a sample-and-hold operation is performed. "RES" indicates a reset operation to reset the charge accumulated in the column signal line 3 or the elements arranged in the readout circuit 12. When signal RES is activated (H), a reset operation is performed. "Output1" indicates the signal read from pixel 1a by the readout circuit 12 and transmitted to the detection circuit 13. "Output2" indicates the signal read from pixel 1b by the reading circuit 12 and transmitted to the detection circuit 13. "Out" represents the difference (Output1 - Output2) between signal Output1 (based on the signal output from pixel 1a) and signal Output2 (based on the signal output from pixel 1b). For example, signal Out can be calculated using signal Output1 and signal Output2 by the arithmetic circuit 2 of the detection circuit 13. The detection circuit 13 detects radiation exposure information based on signal Out.

[0037] Before radiation irradiation begins, the driving circuit 10 sequentially activates signals Vg1 and Vg2 to drive pixels 1a and 1b. Therefore, the detection circuit 13 can detect the start of radiation irradiation. The signals output when pixels 1a and 1b are driven before radiation irradiation begins include offset components generated in transistors arranged in pixels 1a and 1b and the readout circuit 12. Therefore, if radiation irradiation does not occur, the amount of signal Output1 based on the signal output from pixel 1a is substantially equal to the amount of signal Output2 based on the signal output from pixel 1b, and the difference output signal Out becomes substantially zero.

[0038] If radiation irradiation begins, a charge corresponding to the incident radiation is generated in pixel 1a. Conversely, since pixel 1b is blocked from light, a charge corresponding to the offset component is generated, just as before radiation irradiation began. If the drive circuit 10 sequentially activates signals Vg1 and Vg2, the readout circuit 12 sequentially transmits signal Output1 based on the signal read from pixel 1a and signal Output2 based on the signal read from pixel 1b to the detection circuit 13. The detection circuit 13 acquires the signal Output, which is the difference between signal Output1 and signal Output2. Since signals derived from the offset component or crosstalk are suppressed in signal Output, as described above, the detection circuit 13 can obtain radiation irradiation information from signal Output with high accuracy. For example, the detection circuit 13 can accurately detect the start of radiation irradiation from signal Output.

[0039] Furthermore, the dose of the incident radiation can be accurately read from the signal Output, and the detection circuit 13 can accurately acquire the integrated dose. Therefore, the radiation imaging device 100 can accurately perform AEC. During radiation irradiation, when signals are read from pixels 1a and 1b, the crosstalk-derived signal generated from the column signal line 3a is superimposed on the signals output from pixels 1a and 1b, and the signal value increases compared to the case without radiation irradiation. However, since the signals are read in approximately the same time period, the amount of crosstalk signal in the signal output from pixel 1a is approximately the same as the amount of crosstalk signal in the signal output from pixel 1b. Therefore, if the signal Output2 based on the signal read from pixel 1b is subtracted from the signal Output1 based on the signal read from pixel 1a, the influence of the crosstalk signal superimposed on the signals read from pixels 1a and 1b can be suppressed.

[0040] In the radiation imaging device 100, after radiation irradiation begins or AEC (Activated Electron Emission Control) is performed, the detection circuit 13 can stop the control used to detect irradiation information. For example, when AEC is performed, the radiation imaging device 100 predicts the cumulative dose of radiation based on the irradiation information detected by the detection circuit 13, and predicts the irradiation stop timing. Then, when the radiation imaging device 100 outputs the predicted stop timing information or information indicating that radiation irradiation has stopped to the control device for controlling the radiation source, the detection circuit 13 can stop the control used to detect irradiation information. Furthermore, in the drive circuit 10 or the readout circuit 12, preparation for operation to read signals for reading radiation images from each pixel 1 can begin.

[0041] In this manner, when radiation exposure information and radiation images are detected separately, the drive circuit 10 drives pixels 1a and 1b connected to the common column signal line 3 at different timings. Furthermore, the detection circuit 13 detects the radiation exposure information based on signal Output1 from the signal output from pixel 1a and signal Output2 from the signal output from pixel 1b. This allows for the suppression of the circuit size of the readout circuit 12, as well as the suppression of the effects of offset or crosstalk superimposed on the signals output from pixels 1a and 1b, and accurate acquisition of radiation exposure information. Therefore, in the radiation imaging device 100, control for AEC can be performed more accurately, and a radiation imaging device 100 with higher usability is achieved for the user.

[0042] Figure 4 It shows the basis Figure 1A The equivalent circuit diagram of a variant of the radiation imaging device 100, denoted as 100', is shown. Figure 4 In the radiation imaging device 100' shown, the pixels used to allow the detection circuit 13 to obtain radiation exposure information are four pixels, including pixels 1c and 1d, in addition to the aforementioned pixels 1a and 1b. Except for the number of pixels used to allow the detection circuit 13 to obtain radiation exposure information, the radiation imaging device 100' can be the same as the radiation imaging device 100 described above. The differences from the radiation imaging device 100 will be mainly described below, and descriptions of components similar to those in the radiation imaging device 100 will be appropriately omitted.

[0043] In the radiation imaging device 100', pixels 1c and 1d have different sensitivities to radiation. It will be described here as if pixel 1d has a lower sensitivity to radiation than pixel 1c. For example, pixel 1c may have the same configuration as pixel 1a, and pixel 1d may have the same configuration as pixel 1b. For example, in pixels 1a and 1c, the light-shielding layer 22 may not be arranged between the scintillator and the conversion element 20, while in pixels 1b and 1d, the light-shielding layer 22 may be arranged between the scintillator and the conversion element 20. Furthermore, in this case, pixels other than pixels 1a to 1d among the plurality of pixels 1 may have the same configuration as pixels 1a and 1c.

[0044] Pixels 1c and 1d are connected to column signal line 3b, which is different from column signal line 3a, among multiple column signal lines 3, and are respectively connected to drive lines 6a and 6b, which are different from each other, among multiple drive lines 6. Figure 4In the configuration shown, pixel 1d is connected to the same driving line 6a as the driving line to which pixel 1a is connected, and pixel 1c is connected to the same driving line 6b as the driving line to which pixel 1b is connected. However, the invention is not limited to this, and the driving circuit 10 only needs to be able to drive pixels 1c and 1d at different timings. On the other hand, as indicated by the operation described later, in order to improve time resolution, the driving circuit 10 can be configured to drive pixels 1a and 1d at the same timing, and pixels 1b and 1c at the same timing. However, the invention is not limited to this, and pixels 1a to 1d can be driven at different timings. If pixels 1a and 1b can output signals at different timings, and pixels 1c and 1d can output signals at different timings, then radiation irradiation information can be accurately obtained as described above.

[0045] exist Figure 4 In the configuration shown, when drive line 6a is activated, signals are simultaneously transmitted from pixels 1a and 1d to the readout circuit 12. When drive line 6b is activated, signals are simultaneously transmitted from pixels 1b and 1c to the readout circuit 12. In this case, the difference between the combined output signals from pixels 1a and 1b and the difference between the combined output signals from pixels 1c and 1d are alternately acquired. This allows the detection circuit 13 to acquire radiation irradiation information with a time resolution that is [insert time resolution here] without changing the clock rate. Figure 3 The operation shown is twice that of the previous one. For example, if the output of the radiation source is small and the signal gradually increases according to the radiation irradiation, the signals are read from pixel 1a and from pixel 1b at approximately the same timing but not simultaneously. For this reason, the amount of crosstalk may be different, and the accuracy of the irradiation information detection may be reduced. In this case, the reduction in the accuracy of the irradiation information detection can be suppressed by increasing the temporal resolution.

[0046] Figure 5 This is a timing diagram showing the operation of the radiation imaging device 100 when the detection circuit 13 separates and detects the radiation exposure information from the radiation image. "Vg1", "Vg2", "SH", and "RES" are related to... Figure 3 The "Vg1", "Vg2", "SH", and "RES" are similar. "Output1" of column signal line 3a is the signal read from pixel 1a by read circuit 12 and transmitted to detection circuit 13, while "Output2" of column signal line 3a is the signal read from pixel 1b by read circuit 12 and transmitted to detection circuit 13. These are similar to... Figure 3The signals "Output1" and "Output2" in column signal line 3a are used to represent the difference (Output1-Output2) between signal Output1, which is based on the signal output from pixel 1a, and signal Output2, which is based on the signal output from pixel 1b. "Output3" in column signal line 3b is the signal read from pixel 1d by the read circuit 12 and transmitted to the detection circuit 13, while "Output4" in column signal line 3b is the signal read from pixel 1c by the read circuit 12 and transmitted to the detection circuit 13. "Out4-Out3" in column signal line 3b is the difference (Output4-Output3) between signal Output3, which is based on the signal output from pixel 1c, and signal Output4, which is based on the signal output from pixel 1d. "Out" is the signal obtained by superimposing "Output1-Out2" and "Output4-Out3". Signals Out1-Out2, Out4-Out3, and Out can be calculated using signals Output1 to Output4 by, for example, the arithmetic circuit 2 of the detection circuit 13. The detection circuit 13 detects radiation exposure information based on the signal Out.

[0047] Pixels 1a (pixel 1d) and 1b (pixel 1c) may have different overlap capacitances or parasitic capacitances due to different transistor arrangements or misalignments in the exposure apparatus. For this reason, the offset components of pixels 1a (pixel 1d) and 1b (pixel 1c) may also be different. In this case, the offset component correction in signals Out1-Out2 (signals Out4-Out3) may be insufficient, and the radiation exposure information may not be detected with high precision. Therefore, for example, offset data obtained without prior radiation exposure is required. However, the offset components can be corrected with high precision by superimposing signals Out1-Out2 and Out4-Out3.

[0048] Figure 6 It shows from Figure 4 The diagram illustrates an example of the operation and correction of signals Output1 to Output4 from pixels 1a to 1d. If no radiation exposure occurs, the output offset data 1 (offset data 4) is output as signal Output1 (Output4) from pixel 1a (pixel 1c). Conversely, if radiation exposure occurs, signal Output1 (Output4) is obtained by adding offset data 1 (offset data 4) to the radiation data. Since pixel 1b (pixel 1d) is blocked from light, no charge corresponding to the radiation is generated, and output offset data 2 (offset data 3) is output as signal Output2 (Output3) from pixel 1b (pixel 1d).

[0049] exist Figure 4 In the configuration shown, since misalignment may occur in pixels 1a and 1d in almost similar ways, the arrangement, such as the overlap of the metal layers, is almost identical, except for the light-shielding layer. For this reason, offset data 1 and offset data 3 have almost identical values. Similarly, offset data 2 for pixel 1b and offset data 4 for pixel 1c have almost identical values, just as the relationship between pixels 1a and 1d is. Figure 6 As shown, if offset data 1 (offset data 3) is greater than offset data 2 (offset data 4), then signals Out1-Out2 are outputs obtained by adding the difference between offset data 1 and offset data 2 to the radiation data. Similarly, signals Out4-Out3 are outputs obtained by subtracting the difference between offset data 3 and offset data 4 from the radiation data. However, when signals Out1-Out2 and Out4-Out3 are added, the uncorrectable difference between offset data 1 and offset data 2, as well as the difference between offset data 3 and offset data 4, is removed, and information about the radiation data with added pixels 1a and 1c can be obtained. Therefore, radiation exposure information can be detected with high precision.

[0050] If the difference between the offset components of pixel 1a (pixel 1d) and pixel 1b (pixel 1c) can be corrected, then the acquisition of signal Out is not limited to the operations and correction methods described above. For example, signal Out3-Out4 (Output3-Output4) can be acquired as the difference between signal Output3 based on the signal output from pixel 1c and signal Output4 based on the signal output from pixel 1d. In this case, the difference between the offset components of pixel 1a (pixel 1d) and pixel 1b (pixel 1c) can be accurately corrected based on the difference between signals Out1-Out2 and signals Out3-Out4.

[0051] The detection circuit 13 acquires the difference between the signal output from the combination of pixels 1a and 1b and the signal output from the combination of pixels 1c and 1d as signal Out, the two combinations being connected to two column signal lines 3a and 3b. In this case, signals are alternately read from pixels 1a and 1c, which have high sensitivity (and from pixels 1b and 1d, which have low sensitivity). The reading circuit 12 alternately transmits signal Output1 (signal Output2) based on the signal read from pixel 1a (pixel 1b) and signal Output3 (signal Output4) based on the signal read from pixel 1c (pixel 1d) to the detection circuit 13. Therefore, the detection circuit 13 can alternately obtain signals Out1-Out2 and signals Out4-Out3. Thus, with Figure 3Compared to the operation shown, the signal Out used by the detection circuit 13 to detect radiation exposure information can be obtained at the same clock rate but with twice the time resolution. This allows the effects of offset or crosstalk superimposed on the signals output from pixel 1a to pixel 1d to be suppressed, improving the time resolution and accurately obtaining radiation exposure information while reducing the circuit size of the readout circuit 12. Therefore, control for AEC can be performed more accurately, and a radiation imaging device 100' with higher usability can be achieved for the user.

[0052] exist Figure 4 In the configuration shown, pixels 1a to 1d are connected to adjacent column signal lines 3a and 3b. However, the invention is not limited to this; one or more column signal lines 3a and 3b can be arranged between them. Additionally, in Figure 4 In the configuration shown, pixels 1a to 1d are arranged on a single pixel row (AEC row). As described above, a radiographic image can be generated based on the signal output from pixels 1 arranged on the following row: the row other than the pixel row where pixels 1a to 1d are arranged. Therefore, if pixels 1a to 1d are arranged on the same pixel row, the number of AEC rows to be corrected or interpolated is reduced, thus increasing the correction accuracy when generating a radiographic image. However, the invention is not limited to this, and the positions for arranging pixels 1a to 1d can be suitably selected. Pixels 1c and 1d can be as described in reference... Figure 1B and Figure 1C Pixels 1a and 1b can be arranged in the same column, or they can be arranged in different rows and different columns. Pixels 1a through 1d can be arranged in different rows.

[0053] In addition, Figures 1A to 1C as well as Figure 4 In the configuration shown, a pair of pixels 1a and 1b (pixels 1c and 1d) with different sensitivities are arranged on a column signal line 3. However, the invention is not limited to this. Multiple pairs of pixels 1a and 1b can be arranged on a column signal line 3. In this case, signals can be read from multiple pixels 1a (pixels 1b) connected to a column signal line 3 synchronously with the drive switching element 21 (analog addition). Alternatively, for example, signals can be read from multiple pixels 1a (pixels 1b) connected to a column signal line 3 at different timings, and the signal values ​​can be integrated by the arithmetic circuit 2 of the detection circuit 13 (digital addition).

[0054] The following will refer to Figure 7An exemplary radiographic system incorporating the aforementioned radiographic imaging apparatus 100 or 100' is described. X-rays 6060 generated by an X-ray tube 6050 pass through the chest 6062 of a patient or subject 6061 and enter the radiographic imaging apparatus 100 or 100', the X-ray tube 6050 acting as a radiation source for emitting radiation to the radiographic imaging apparatus 100 or 100'. The incident X-rays contain internal bodily information of the patient or subject 6061. In the radiographic imaging apparatus 100 or 100', a scintillator emits light in response to the entry of the X-rays 6060, and the emitted light undergoes photoelectric conversion by a conversion element 20 to obtain electrical information. This information is converted into digital data, image processed by an image processor 6070 acting as a signal processing unit, and can be viewed on a display 6080 acting as a display unit in a control room.

[0055] Additionally, this information can be transmitted to a remote location via a transmission processing unit such as a telephone network 6090. This allows the information to be displayed on a monitor 6081, which acts as a display unit in a doctor's office or elsewhere, and allows a doctor at a remote location to make a diagnosis. Furthermore, the information can be recorded on a recording medium such as an optical disc, and a film developing and processing machine 6100 can also record the information on film 6110, which acts as a recording medium.

[0056] Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The appended claims should be interpreted in the broadest possible sense to cover all such variations and equivalent results and functions.

Claims

1. A radiation imaging device, the radiation imaging device comprising: Multiple pixels, which are arranged to form multiple rows and multiple columns; A driving circuit configured to control the plurality of pixels via a plurality of driving lines extending along the row direction; A readout circuit configured to read signals generated by the plurality of pixels via a plurality of column signal lines; as well as A detection circuit, configured to separately detect radiation exposure information and radiation images based on the signal read by the readout circuit. Each of the plurality of column signal lines is connected to a pixel in the plurality of pixels arranged in two adjacent pixel columns along the row direction. The plurality of pixels includes a first pixel and a second pixel that have different sensitivities to radiation. The first pixel and the second pixel are connected to a common column signal line among the plurality of column signal lines, and are also connected to different drive lines among the plurality of drive lines. When the irradiation information is detected The driving circuit is configured to drive the first pixel and the second pixel at different timings. The detection circuit is configured to detect the illumination information based on the signal output from the first pixel and the signal output from the second pixel.

2. The apparatus according to claim 1, wherein, When the illumination information is detected, the detection circuit is configured to detect the illumination information based on the difference between the signal output from the first pixel and the signal output from the second pixel.

3. The apparatus according to claim 1, wherein, Among the plurality of pixels, two pixels that are adjacent to each other along the row direction and connected to the common column signal line have a configuration that is either line-symmetric or point-symmetric across the common column signal line.

4. The apparatus according to claim 1, wherein, The first pixel and the second pixel are arranged in the same row.

5. The apparatus according to claim 1, wherein, The first pixel and the second pixel are arranged in the same column.

6. The apparatus according to claim 1, wherein, The first pixel and the second pixel are arranged in different rows and different columns.

7. The apparatus according to claim 1, wherein, The plurality of pixels includes a third pixel and a fourth pixel that have different sensitivities to radiation. The shared column signal line is defined as the first column signal line. The third pixel and the fourth pixel are connected to a second column of signal lines that are different from the first column of signal lines, and are also connected to different drive lines among the multiple drive lines. When the irradiation information is detected The driving circuit is configured to drive the third pixel and the fourth pixel at different timings. The driving circuit is configured to further detect the illumination information based on the signals output from the third pixel and the signals output from the fourth pixel.

8. The apparatus according to claim 7, wherein, When the illumination information is detected, the driving circuit is configured to drive the first pixel and the third pixel at the same timing, and is also configured to drive the second pixel and the fourth pixel at the same timing.

9. The apparatus according to claim 3, wherein, The plurality of pixels includes a third pixel and a fourth pixel that have different sensitivities to radiation. The shared column signal line is defined as the first column signal line. The third pixel and the fourth pixel are connected to a second column of signal lines that is different from the first column of signal lines. The third pixel is connected to the same driving line as the first pixel among the plurality of driving lines. The fourth pixel is connected to the same driving line as the driving line connected to the second pixel among the plurality of driving lines, and When the illumination information is detected, the driving circuit is configured to further detect the illumination information based on the signal output from the third pixel and the signal output from the fourth pixel.

10. The apparatus according to claim 7, wherein, When the illumination information is detected, the detection circuit is configured to further detect the illumination information based on the difference between the signal output from the third pixel and the signal output from the fourth pixel.

11. The apparatus according to claim 10, wherein, When the illumination information is detected, the detection circuit is configured to detect the illumination information based on the difference between the signal output from the first pixel and the signal output from the second pixel, and the difference between the signal output from the third pixel and the signal output from the fourth pixel.

12. The apparatus according to claim 7, wherein, The first pixel is more sensitive to radiation than the second pixel, and The third pixel is less sensitive to radiation than the fourth pixel.

13. The apparatus according to claim 7, wherein, The radiation image is generated based on signals output from pixels arranged in the following pixel rows: the pixel rows are pixel rows other than the pixel rows in which the first pixel, the second pixel, the third pixel, and the fourth pixel are arranged.

14. The apparatus of claim 7, further comprising: A scintillator, the scintillator being arranged to cover the plurality of pixels; as well as A light-shielding layer is disposed between the second pixel and the scintillator and between the fourth pixel and the scintillator.

15. The apparatus according to claim 1, wherein, The radiation image is generated based on signals output from pixels arranged in the following pixel rows: the pixel rows are pixel rows other than the pixel rows in which the first pixel and the second pixel are arranged.

16. The apparatus according to claim 1, further comprising: A scintillator, the scintillator being arranged to cover the plurality of pixels, and A light-shielding layer is disposed between the second pixel and the scintillator.

17. A radiation imaging system, the radiation imaging system comprising: The radiation imaging apparatus according to any one of claims 1 to 16; as well as A signal processing unit configured to process signals output from the radiation imaging device.

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