WO2017010202A1 - 放射線検出器 - Google Patents
放射線検出器 Download PDFInfo
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- WO2017010202A1 WO2017010202A1 PCT/JP2016/067283 JP2016067283W WO2017010202A1 WO 2017010202 A1 WO2017010202 A1 WO 2017010202A1 JP 2016067283 W JP2016067283 W JP 2016067283W WO 2017010202 A1 WO2017010202 A1 WO 2017010202A1
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- 230000005855 radiation Effects 0.000 title claims abstract description 67
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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
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- 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
-
- 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
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- 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
- H01L27/14643—Photodiode arrays; MOS imagers
- H01L27/14658—X-ray, gamma-ray or corpuscular radiation imagers
- H01L27/14659—Direct radiation imagers structures
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/30—Circuitry of solid-state image sensors [SSIS]; Control thereof for transforming X-rays into image signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/70—SSIS architectures; Circuits associated therewith
- H04N25/71—Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors
- H04N25/75—Circuitry for providing, modifying or processing image signals from the pixel array
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/70—SSIS architectures; Circuits associated therewith
- H04N25/76—Addressed sensors, e.g. MOS or CMOS sensors
- H04N25/78—Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters
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- 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 radiation detector that detects radiation such as X-rays.
- radiation detectors radiation imagers
- TFT Thin-film Transistor
- CCD Charge-Coupled Device
- CMOS Complementary-Mental-Oxide-Semiconductor Device
- a radiation detector using a TFT panel has an imaging circuit in which a large number of pixels (pixels) are arranged two-dimensionally. Then, a physical quantity corresponding to the X-ray dose (radiation dose) is converted into a signal in each pixel, and imaging is performed by measuring the converted signal.
- One method is a method of reading out the charge amount (carrier amount) accumulated in each pixel as it is, and is called a PPS (Passive Pixel Sensor) method.
- PPS Passive Pixel Sensor
- Another method is a method of generating a potential or current corresponding to the amount of charge accumulated in each pixel and reading the generated potential or current, and is called an APS (Active Pixel Sensor) method.
- the PPS panel has been put into practical use prior to the APS system because the potential of the pixel is reset each time it is read and the usage method is relatively simple.
- a PPS readout circuit for reading out the amount of charge accumulated in each pixel has also been put into practical use.
- the readout circuit for the PPS system is usually created separately from the TFT panel by a CMOS process or the like, and is connected to the TFT panel via a flexible substrate.
- FIG. 7 is an explanatory diagram showing a configuration example of one pixel 100 and a readout circuit 120 connected to the pixel 100 in a conventional PPS type radiation detector.
- the pixel 100 includes a photodiode 101, a charge storage unit (charge storage node) 102, and a readout switch 103.
- the photodiode 101 photoelectrically converts light (radiation) in a predetermined frequency band incident from the outside, and accumulates charges generated by the photoelectric conversion in the charge accumulation unit 102. As a result, charges corresponding to the amount of light incident on the photodiode 101 are accumulated in the charge accumulation unit 102.
- the read switch 103 has one end connected to the charge storage unit 102 and the other end connected to the signal output line 110. In accordance with an instruction from a control unit (not shown) between the charge storage unit 102 and the signal output line 110. Switch between cut-off and conduction.
- the readout circuit 120 includes an amplifier reset switch 121, a feedback capacitor 122, and a readout amplifier 123.
- the input terminal of the read amplifier 123 is connected to the signal output line 110, one end side of the feedback capacitor 122, and one end side of the amplifier reset switch 121.
- the output terminal of the read amplifier 123 is connected to the read amplifier output line 130, the other end side of the feedback capacitor 122, and the other end side of the amplifier reset switch 121.
- V out Q sig / C F (1)
- the potential of the signal output line 110 is set to a predetermined potential by feedback of the read amplifier 123.
- the reading switch 103 is opened (turned off), and the charge storage unit 102 and the signal output line 110 are cut off, and the photoelectric conversion signal is stored again in the charge storage unit 102.
- the radiation detector it is necessary to improve the S / N ratio in order to realize further lower dose or higher resolution in the detectable range.
- the APS method is considered promising.
- the output of each pixel is a charge amount, and in the APS method, it is usually a current amount. Further, a charge integration circuit is usually used as a readout circuit for reading out the output from each pixel.
- the PPS method since the output signal from the pixel is a current, when the conversion efficiency from the same light amount (radiation amount) to the charge is the same by increasing the integration time, the PPS method A large signal can be obtained as compared with the reading circuit.
- Patent Document 2 a method disclosed in Patent Document 2 can be used as a method for determining an operating point when performing the above-described initialization operation.
- the method of Patent Document 2 is a method of applying feedback so that the output becomes equal to the reference voltage when a certain pixel is selected.
- the current flowing through the pixel is determined by the load transistor.
- each pixel 100 includes, in addition to the configuration of the pixel 100 illustrated in FIG. 7, a pixel reset switch 104 connected to the charge accumulation unit 102, and between the charge accumulation unit 102 and the readout switch 103. And an amplifier transistor 105 connected to each other.
- the pixel reset switch 104 is switched to a conductive state when the reference voltage of the photodiode 101 is set. That is, the pixel reset switch 104 is a switch for resetting the potentials of the photodiode 101 and the charge storage unit 102 to a reset potential corresponding to a predetermined reference voltage. The potentials of the photodiode 101 and the charge storage unit 102 are reset every time a current corresponding to the amount of charge stored in the charge storage unit 102 is read or every predetermined number of times.
- the amplifier transistor 105 converts a voltage signal corresponding to the charge stored in the charge storage unit 102 into a current signal, and outputs the current signal to the signal output line 110 via the readout switch 103.
- the photodiode 101 When light is incident on the photodiode 101, photoelectric conversion is performed by the photodiode 101, charges are accumulated in the charge accumulation unit 102, and the potential of the charge accumulation unit 102 changes from the reset potential. Thereafter, when the read switch 103 is turned on, the amplifier transistor 105 functions as a common drain amplifier and outputs a current corresponding to the changed voltage. At this time, the signal output line 110 is set to a predetermined potential by the feedback of the read amplifier 123.
- the output potential V out of the read amplifier 123 is such that the signal charge is Q sig , the capacitance of the photodiode 101 is C PD , the mutual conductance of the amplifier transistor 105 is g m , and the bias current flowing through the amplifier transistor 105 at the reset potential is I
- the following equation (2) is obtained.
- V out (g m ⁇ Q sig / C PD + I B ) ⁇ t / C F (2)
- the current value corresponding to the potential change from the reset potential is the original output signal.
- the present invention has been made in view of the above-described problems, and an object of the present invention is to widen the detectable range of an output signal corresponding to the charge accumulated in a pixel in an APS radiation detector. .
- a radiation detector includes a charge accumulation unit that accumulates charges according to a radiation dose, and a current signal generation unit that generates a current signal according to the charge amount accumulated in the charge accumulation unit.
- a radiation detector comprising: a pixel having a signal output line connected to the pixel; and a signal readout circuit for reading out the current signal input from the pixel via the signal output line, A current adjustment unit connected to a region of the line between the pixel and the signal readout circuit, wherein the current adjustment unit is a bias that flows to the current signal generation unit when no charge is accumulated in the charge accumulation unit It is characterized in that a current substantially equivalent to a current is drawn from the signal output line or flows into the signal output line.
- FIG. 8 is an explanatory diagram illustrating a configuration example of a pixel and a readout circuit when the readout circuit illustrated in FIG. 7 is applied to an APS radiation detector.
- Embodiment 1 An embodiment of the present invention will be described.
- FIG. 1 is an explanatory diagram showing a schematic configuration of a radiation detector 1 according to the present embodiment.
- the radiation detector 1 includes a pixel substrate 10, an FPC substrate (flexible printed circuit board) 20, a signal processing circuit substrate 30, and an FPC substrate 40.
- the pixel substrate 10 is a substantially rectangular glass substrate. On the substrate surface of the pixel substrate 10, a pixel region 11 in which a plurality of pixels 12 are formed in a matrix (array) and pixels 12 are not formed. A non-pixel region 11b is formed. The pixel region 11 is disposed at the center of the substrate surface of the pixel substrate 10, and the non-pixel region 11 b is disposed so as to surround the pixel region 11 at the peripheral edge of the substrate surface of the pixel substrate 10.
- the material of the pixel substrate 10 is not limited to glass, and may be a resin, for example. Further, the shapes of the pixel substrate 10 and the pixel region 11 are not limited to rectangular shapes, and may be arbitrary shapes.
- the FPC board 20 is disposed so as to connect one end of the pixel substrate 10 and one end of the signal processing circuit board 30.
- a signal readout circuit 21 is formed on the FPC board 20.
- the signal readout circuit 21 an existing readout circuit used as a readout circuit for the PPS system is used.
- two FPC boards 20 each having the signal readout circuit 21 are provided, but the number of FPC boards 20 is not limited to this.
- the signal processing circuit board 30 acquires an output signal corresponding to the electric charge accumulated in each pixel from the signal readout circuit 21, and the amount of radiation incident on each pixel and the pixel region 11 according to the acquired output signal of each pixel. Calculation of radiation dose distribution at
- the FPC substrate 40 is connected to the other end of the pixel substrate 10 (an end on the opposite side of the pixel substrate 11 with respect to the end of the pixel substrate 10 to which the FPC substrate 20 is connected).
- a resistor array IC (current adjustment unit) 41 is formed on the FPC board 40.
- a signal output line 51 (see FIG. 2 to be described later) for connecting each pixel 12 and the signal readout circuit 21 is parallel to the opposing direction of the FPC board 20 and the FPC board 40 (pixel board). 10 along the longitudinal direction of FIG.
- two FPC substrates 40 each having the resistor array IC 41 are connected to the pixel substrate 10, but the number of FPC substrates 40 is not limited to this.
- FIG. 2 is an explanatory diagram showing the configuration of the pixel 12, the resistor array IC 41, and the signal readout circuit 21.
- one of the many pixels 12 arranged in the pixel region 11 and one pixel 12 among the plurality of resistors (current setting resistors) 42 provided in the resistor array IC 41 correspond to the one pixel 12. Only one portion of the signal readout circuit 21 connected to the one pixel 12 is shown.
- the pixel 12 includes a photodiode 13, a charge storage unit (charge storage node) 14, a pixel reset switch 15, an amplifier transistor (current signal generation unit) 16, and a readout switch 17.
- the photodiode 13 photoelectrically converts light in a predetermined frequency band (radiation such as X-rays) incident on the pixel 12 and outputs the charge generated by the photoelectric conversion to the charge storage unit 102. As a result, charges corresponding to the amount of light incident on the photodiode 13 in a predetermined frequency band are accumulated in the charge accumulation unit 14.
- a predetermined frequency band radiation such as X-rays
- the pixel reset switch 15 is a switch for resetting the potentials of the photodiode 13 and the charge storage unit 14 to a predetermined reset potential.
- the pixel reset switch 15 is connected to a control unit (not shown) of the radiation detector 1 and opens and closes according to an instruction from the control unit.
- the control unit closes the pixel reset switch 15 every time the current corresponding to the amount of charge stored in the charge storage unit 14 is read out or every time a predetermined number of readings are performed.
- a potential supply source (not shown) that supplies a reset potential and the charge storage unit 14 are brought into conduction, and the potentials of the photodiode 13 and the charge storage unit 14 are reset to the reset potential.
- the amplifier transistor 16 converts a voltage signal corresponding to the charge stored in the charge storage unit 14 into a current signal, and outputs the current signal to the signal output line 51 via the read switch 103.
- the readout switch 17 is connected to a control unit (not shown) of the radiation detector 1 and opens and closes according to an instruction from the control unit.
- the control unit closes the readout switch 17 at every predetermined timing, and causes the signal output line 51 to output a current corresponding to the amount of charge stored in the charge storage unit 14.
- the signal output line 51 has one end connected to the readout switch 17 of the pixel 12 and the other end connected to a portion corresponding to the pixel 12 in the signal readout circuit 21.
- the signal output line 51 is connected to one of a plurality of resistors (current adjusting units) 42 provided in the resistor array IC 41 via a resistor connection line 52.
- the resistor 42 connected to the signal output line 51 for each pixel 12, the bias current I B flowing through the amplifier transistor 16 of the pixel 12 when the reset potential, closing the readout switch 17
- the resistor 42 in which the resistance value and the potential difference at both ends are set to flow through the resistor 42 is selected.
- the bias current I B and substantially equalizing current flowing through the amplifier transistor 16 flows through the resistor 42, so as not to flow into the feedback capacitor 23 Yes.
- the signal readout circuit 21 includes a readout amplifier 22, a feedback capacitor 23, and an amplifier reset switch 24.
- a signal output line 51, one end side of the feedback capacitor 23, and one end side of the amplifier reset switch 24 are connected to the input stage of the read amplifier 22.
- the output stage of the read amplifier 22 is connected to the read amplifier output line 53, the other end side of the feedback capacitor 23, and the other end side of the amplifier reset switch 24.
- the read amplifier output line 53 is connected to a calculation unit (not shown) provided in the signal processing circuit board 30.
- the signal read from the pixel 12 by the read amplifier 22 is transmitted to the arithmetic unit provided in the signal processing circuit board 30, and the arithmetic part (not shown) of the signal processing circuit board 30 reads from each pixel 12.
- Predetermined processing for example, calculation of the radiation dose incident on each pixel 12 or calculation of the radiation dose distribution in the pixel region 11 is performed based on the output signal.
- the resistance value of the resistor 42 connected to the signal output line 51 corresponding to each pixel 12 and the potential difference between both ends are determined when the potential of the charge storage unit 14 is the reset potential.
- bias current I B and substantially equalizing current flowing through the amplifier transistor 16 of the 12 is set to flow in the resistor 42 when closing the readout switch 17.
- the potential (reset potential) of the charge storage unit 14 at the time of reset is V RESET and the on-resistance of the read switch 17 can be ignored.
- the output current output to the signal output line 51 is an amplifier. bias current I B next to the transistors 16, represented by the following formula (3).
- the resistance value R of the resistor 42 is set so as to substantially satisfy the following formula (4). Note that the potential of the signal output line 51 converges to a predetermined potential by feedback of the read amplifier 22, so that a predetermined potential difference is applied to the resistor 42.
- the potential change amount V SIG of the charge accumulation unit 14 is Q SIG as the signal charge amount and the capacitance of the charge accumulation unit 14 as C PD. Then, it is represented by the following formula (5).
- V SIG Q SIG / C PD (5)
- the amount of increase in current I SIG according to the amount of charge stored in the charge storage unit 14 is expressed by the following equation (6), where g m is the mutual conductance of the amplifier transistor 16.
- I SIG g m ⁇ V SIG (6)
- the total output current from the read switch 17 to the signal output line 51 is I B + I SIG .
- V OUT g m ⁇ t / C F ⁇ V SIG (7)
- the resistor 42 is connected to the signal output line 51, so that the dynamic range can be effectively utilized by the following equation (8). I understand that. In other words, by connecting the resistor 42 to the signal output line 51, it is possible to perform the APS system reading while suppressing the loss of the dynamic range by using the conventional signal readout circuit 21 for the PPS system.
- the radiation detector 1 includes the pixel 12 having the amplifier transistor 16 that converts the voltage signal corresponding to the charge accumulated in the charge accumulation unit 14 into a current signal, and the output from the amplifier transistor 16.
- the signal readout circuit 21 for reading out the current signal to be read and the signal readout circuit 21 for reading out the current signal input from the pixel 12 via the signal output line 51 are provided.
- a resistor 42 is connected to the signal output line 51. are, resistance value and the potential difference across the resistor 42, the bias current I B and substantially equalizing current is the resistor 42 flowing through the amplifier transistor 16 when the charges stored in the charge storage section 14 is zero It is set to flow.
- the FPC substrate 20 having the signal readout circuit 21 is connected to one end side of the pixel substrate 10, and the resistor array IC 41 is formed in a region outside the pixel region 11 on the other end side of the pixel substrate 10.
- An FPC board 40 is connected.
- each resistor 42 provided in the resistor array IC 41 since current flows corresponding to the bias current I B flowing through the amplifier transistor 16, there is a case where the heating occurs.
- the pixel 12 is configured by an element such as a diode or a TFT, and the operation characteristics of the pixel 12 are temperature dependent.
- the resistor array IC 41 is disposed at a position (non-pixel region 11b) away from the pixel region 11, the temperature of each pixel 12 is generated even when the resistor array IC 41 generates heat. It is possible to stabilize the operation of each pixel 12 by suppressing the occurrence of change and suppressing the occurrence of noise in the output signal of each pixel 12.
- the configuration in which the FPC substrate 40 on which the resistor array IC 41 is formed is connected to the pixel substrate 10 has been described.
- the present invention is not limited to this.
- the resistor array IC 41 may be directly connected to the pixel substrate 10 by soldering or the like.
- the resistor array IC 41 may be formed on a hard substrate such as a glass substrate or a resin substrate, and the substrate on which the resistor array IC 41 is formed may be connected to the pixel substrate 10.
- FIG. 3 is an explanatory diagram illustrating the configuration of the pixel 12, the constant current source array IC (current adjustment unit) 43, and the signal readout circuit 21 in the radiation detector 1 according to the present embodiment.
- the radiation detector 1 according to the present embodiment is different from the radiation detector 1 according to the first embodiment in that a constant current source array IC 43 is provided instead of the resistor array IC 41.
- the constant current source array IC43 is provided on the FPC board 40 in place of the resistor array IC41.
- the constant current source array IC 43 includes a constant current source circuit (current adjustment unit) 44, and the constant current source circuit 44 is connected to the signal output line 51.
- the constant current source circuit 44 to draw a bias current I B and substantially equalizing current flowing through the amplifier transistor 16 when the charge stored in the charge storage portion 14 of the pixel 12 is zero from the signal output line 51 Is set.
- FIG. 4 is an explanatory diagram showing a schematic configuration of the radiation detector 1 according to the present embodiment.
- an FPC board 40 having a resistor array IC 41 and an FPC board 20 having a signal readout circuit 21 are provided on both one end side and the other end side in the longitudinal direction of the pixel substrate 10. It is connected. Further, the signal readout circuit 21 arranged on one end side and the signal readout circuit 21 arranged on the other end side are respectively connected to different signal processing circuit boards 30.
- Each signal output line 51 may extend from one end side to the other end side of the pixel region 11, and a signal readout circuit that reads out the output signal of the pixel 12 output via the signal output line 51. It may extend from 21 to the center of the pixel region 11. That is, the signal output line 51 extends from the longitudinal center of the pixel substrate 10 to one end side in the longitudinal direction, and the signal extends from the longitudinal center of the pixel substrate 10 to the other end side in the longitudinal direction. It may be formed separately from the output line 51.
- the signal readout circuit 21 When the resistance of the signal output line 51 in the pixel region 11 is relatively large (for example, when the size of the pixel region 11 is large, etc.), if the signal readout circuit 21 is disposed only on one end side in the extending direction of the signal output line 51, Depending on the distance from 12 to the signal readout circuit 21, a difference in the amount of voltage drop may occur, and uniform detection accuracy may not be obtained in the entire pixel region 11.
- signal readout circuits 21 are provided at both ends of the signal output line 51 in the extending direction, and the output signal of each pixel 12 is read out using the signal readout circuit 21 closer to the pixel 12.
- the influence of the voltage drop according to the distance from the pixel 12 to the signal readout circuit 21 can be reduced. Therefore, for example, even in a large-screen radiation detector (large-screen radiation image capturing apparatus) in which the size of the pixel region 11 is large, uniform detection accuracy can be realized in the entire pixel region 11.
- the FPC board 40 provided with the resistor array IC 41 is connected to the outside of the pixel region 11 in the pixel board 10. Thereby, similarly to the first embodiment, it is possible to suppress the temperature change of each pixel 12 due to the heat generated by the resistor array IC 41 and to stabilize the operation of each pixel 12.
- a constant current source array IC43 may be provided instead of the resistor array IC41, and in this case, substantially the same effect can be obtained.
- FIG. 5 is an explanatory diagram showing a schematic configuration of the radiation detector 1 according to the present embodiment.
- an FPC board 40 having a resistor array IC 41 and an FPC board 20 having a signal readout circuit 21 are connected to one end side in the longitudinal direction of the pixel substrate 10.
- the distance between the resistor array IC 41 and the signal readout circuit 21 can be shortened, so that the wiring structure can be simplified by shortening the wiring routing distance.
- a constant current source array IC43 may be provided instead of the resistor array IC41, and in this case, substantially the same effect can be obtained.
- FIG. 6 is an explanatory diagram showing a schematic configuration of the radiation detector 1 according to the present embodiment.
- an FPC board 20 having a signal readout circuit 21 is formed on one end side in the longitudinal direction of the pixel substrate 10, and an FPC having resistor array ICs 41 on both end sides in the short side direction.
- a substrate 40 is connected.
- the distance between the resistor array IC 41 and the signal readout circuit 21 can be shortened, so that the wiring structure can be simplified by shortening the wiring routing distance.
- a constant current source array IC43 may be provided instead of the resistor array IC41, and in this case, substantially the same effect can be obtained.
- the configuration in which light (radiation) is detected by the photodiode 13 provided in each pixel 12 has been described.
- the application target of the present invention is not limited to this, and light is emitted by other methods.
- the present invention can also be applied to a configuration in which charges corresponding to the amount of incident (radiation) are stored in the charge storage unit 14.
- the circuit configurations shown in the above embodiments are merely examples, and the present invention is not limited to the circuit configurations described above.
- the amplifier transistor 16 may be configured to pour a current of predetermined value in response to the bias current I B of the amplifier transistor 16 to the signal output line 51.
- a radiation detector 1 includes a charge accumulation unit 14 that accumulates charges according to a radiation dose, and a current signal generation that generates a current signal according to the charge amount accumulated in the charge accumulation unit 14.
- a pixel 12 having a section (amplifier transistor 16), a signal output line 51 connected to the pixel 12, and a signal readout circuit 21 for reading out the current signal input from the pixel 12 through the signal output line 51.
- a current adjustment unit resistor 42, constant current source circuit 44
- the current adjusting unit includes a via that flows to the current signal generation unit (amplifier transistor 16) when no charge is stored in the charge storage unit 14. Or draws current substantially equivalent to the current from the signal output line 51, or is characterized by pouring into said signal output line 51.
- the radiation detector 1 includes the pixel substrate 10 on which the plurality of pixels 12 are formed in the aspect 1, and the current adjustment unit (resistor 42, constant current source circuit 44) includes:
- the pixel substrate 10 is formed separately from the pixel substrate 10 and connected to the pixel substrate 10.
- the current adjustment unit (resistor 42, constant current source circuit 44) is simply connected to the existing pixel substrate 10 and the signal output line 51, and according to the amount of charge stored in the charge storage unit 14.
- the detectable range of the current signal can be expanded.
- the pixel region 11 in which the plurality of the pixels 12 are formed and the pixels 12 are formed on the substrate surface of the pixel substrate 10 in the aspect 2 described above.
- each pixel 12 can be operated stably.
- the radiation detector 1 according to the aspect 4 of the present invention has a configuration in which the current adjusting unit is the resistor 42 or the constant current source circuit 44 in any one of the above aspects 1 to 3.
- a configuration for easily drawing a current substantially equivalent to a bias current flowing through the current signal generation unit (amplifier transistor 16) from the signal output line 51 or flowing it into the signal output line 51 is easily realized. it can.
- a radiation detector 1 includes the pixel substrate 10 on which the plurality of pixels 12 are formed in any one of the above aspects 1 to 4, and the signal readout circuit 21 includes the pixel substrate 10 and the pixel substrate 10. Is formed as a separate body and connected to the pixel substrate 10. On the substrate surface of the pixel substrate 10, a pixel region 11 in which a plurality of the pixels 12 are formed and the pixels 12 are not formed. A non-pixel region 11b is formed, and the separate signal readout circuits 21 are connected to positions on both ends of the pixel substrate 10 facing each other across the pixel region 11 in the non-pixel region 11b. Each of the pixels 12 is connected to the signal readout circuit 21 on the side closer to the pixel 12 among the signal readout circuits 21 arranged with the pixel region 11 interposed therebetween via the signal output line 51. It is configured to output a signal.
- the influence of the voltage drop according to the distance from the pixel 12 to the signal readout circuit 21 in the signal output line 51 on the signal detection accuracy of the signal readout circuit 21 can be reduced. Therefore, for example, even when the size of the pixel region 11 is large, uniform detection accuracy can be realized in the entire pixel region 11.
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Abstract
Description
この際、信号出力線110の電位は、読出アンプ123のフィードバックにより、所定の電位に設定される。読み出しが終わると、読出スイッチ103は開かれ(オフされ)、電荷蓄積部102と信号出力線110との間が遮断されて電荷蓄積部102に再び光電変換信号が蓄積されていく。
この演算を行うことにより、フォトダイオード101によって電荷蓄積部102に蓄積された電荷量に応じた出力が読み出される。そして、時間tが経過して読み出しが終わると、読出スイッチ103は開かれ、電荷蓄積部102に再び光電変換信号が蓄積されていく。
本発明の一実施形態について説明する。
図1は、本実施形態にかかる放射線検出器1の概略構成を示す説明図である。この図に示すように、放射線検出器1は、画素基板10、FPC基板(フレキシブルプリント基板)20、信号処理回路基板30、およびFPC基板40を備えている。
図2は、画素12、抵抗アレイIC41、および信号読出回路21の構成を示す説明図である。なお、図2では、画素領域11に配置された多数の画素12のうちの1つと、抵抗アレイIC41に備えられる複数の抵抗器(電流設定抵抗)42のうちの上記1つの画素12に対応する1つと、信号読出回路21における上記1つの画素12に接続された部分のみを示している。
上述したように、本実施形態では、各画素12に対応する信号出力線51に接続される抵抗器42の抵抗値および両端電位差が、電荷蓄積部14の電位がリセット電位であるときに当該画素12のアンプトランジスタ16に流れるバイアス電流IBと略等化な電流が読出スイッチ17を閉じたときに当該抵抗器42に流れるように設定されている。これにより、本実施形態では、バイアス電流IBが読出アンプ22に入力されることを防止することができるので、読出アンプ22における画素12からの出力信号の検出可能範囲を広げることができる。
また、本実施形態では、抵抗器42の抵抗値Rを、下記式(4)を概ね満たすようしておく。なお、信号出力線51の電位は、読出アンプ22のフィードバックにより所定の電位に収束するので、抵抗器42には所定の電位差が印加される。
これにより、信号がない状態(電荷蓄積部14に電荷が蓄積されていない状態)で読出スイッチ17を閉じたときに帰還容量23へ流れ込む電流は概ね0となる。
電荷蓄積部14に蓄積された電荷量に応じた電流の増加量ISIGは、アンプトランジスタ16の相互コンダクタンスをgmとすると、下記式(6)となる。
また、読出スイッチ17から信号出力線51への全体の出力電流はIB+ISIGとなる。
読み出しが終わると、読出スイッチ17は開かれ(読出スイッチ17はオフされ)、フォトダイオード13および電荷蓄積部14に再び光電変換信号が蓄積されていく。
以上のように、本実施形態にかかる放射線検出器1は、電荷蓄積部14に蓄積された電荷に応じた電圧信号を電流信号に変換するアンプトランジスタ16を有する画素12と、アンプトランジスタ16から出力される電流信号を読み出す信号読出回路21と、画素12から信号出力線51を介して入力される電流信号を読み出す信号読出回路21とを備えており、信号出力線51に、抵抗器42が接続されており、抵抗器42の抵抗値および両端電位差が、電荷蓄積部14に蓄積された電荷がゼロのときにアンプトランジスタ16に流れるバイアス電流IBと略等化な電流が当該抵抗器42に流れるように設定されている。
本発明の他の実施形態について説明する。なお、説明の便宜上、上述した実施形態で説明した部材と同じ機能を有する部材については、同じ符号を付記し、その説明を省略する。
本発明のさらに他の実施形態について説明する。なお、説明の便宜上、上述した実施形態で説明した部材と同じ機能を有する部材については、同じ符号を付記し、その説明を省略する。
本発明のさらに他の実施形態について説明する。なお、説明の便宜上、上述した実施形態で説明した部材と同じ機能を有する部材については、同じ符号を付記し、その説明を省略する。
本発明のさらに他の実施形態について説明する。なお、説明の便宜上、上述した実施形態で説明した部材と同じ機能を有する部材については、同じ符号を付記し、その説明を省略する。
本発明の態様1にかかる放射線検出器1は、放射線量に応じた電荷を蓄積する電荷蓄積部14と、前記電荷蓄積部14に蓄積された電荷量に応じた電流信号を生成する電流信号生成部(アンプトランジスタ16)とを有する画素12と、前記画素12に接続された信号出力線51と、前記画素12から前記信号出力線51を介して入力される前記電流信号を読み出す信号読出回路21とを備えた放射線検出器1であって、前記信号出力線51における前記画素12と前記信号読出回路21との間の領域に接続された電流調整部(抵抗器42、定電流源回路44)を備え、前記電流調整部(抵抗器42、定電流源回路44)は、前記電荷蓄積部14に電荷が蓄積されていない時に前記電流信号生成部(アンプトランジスタ16)に流れるバイアス電流と略等価な電流を前記信号出力線51から引き出すか、あるいは前記信号出力線51に流し込むことを特徴としている。
10 画素基板
11 画素領域
11b 非画素領域
12 画素
13 フォトダイオード
14 電荷蓄積部
15 画素リセットスイッチ
16 アンプトランジスタ(電流信号生成部)
17 読出スイッチ
20 FPC基板
21 信号読出回路
22 読出アンプ
23 帰還容量
24 アンプリセットスイッチ
30 信号処理回路基板
40 FPC基板
41 抵抗アレイIC
42 抵抗器(電流調整部)
43 定電流源アレイIC
44 定電流源回路(電流調整部)
51 信号出力線
52 抵抗接続線
53 読出アンプ出力線
Claims (5)
- 放射線量に応じた電荷を蓄積する電荷蓄積部と、前記電荷蓄積部に蓄積された電荷量に応じた電流信号を生成する電流信号生成部とを有する画素と、前記画素に接続された信号出力線と、前記画素から前記信号出力線を介して入力される前記電流信号を読み出す信号読出回路とを備えた放射線検出器であって、
前記信号出力線における前記画素と前記信号読出回路との間の領域に接続された電流調整部を備え、
前記電流調整部は、前記電荷蓄積部に電荷が蓄積されていない時に前記電流信号生成部に流れるバイアス電流と略等価な電流を前記信号出力線から引き出すか、あるいは前記信号出力線に流し込むことを特徴とする放射線検出器。 - 複数の前記画素が形成された画素基板を備え、
前記電流調整部は、前記画素基板とは別体として形成されて前記画素基板に接続されていることを特徴とする請求項1に記載の放射線検出器。 - 前記画素基板の基板面上に、複数の前記画素が形成されている画素領域と、前記画素が形成されていない非画素領域とが形成されており、前記画素領域は前記基板面の中央部に配置され、前記非画素領域は前記基板面の周縁部に配置されており、
前記電流調整部は、前記画素基板の前記非画素領域に接続されていることを特徴とする請求項2に記載の放射線検出器。 - 前記電流調整部は、抵抗器または定電流源回路であることを特徴とする請求項1から3のいずれか1項に記載の放射線検出器。
- 複数の前記画素が形成された画素基板を備え、
前記信号読出回路は、前記画素基板とは別体として形成されて前記画素基板に接続されており、
前記画素基板の基板面上に、複数の前記画素が形成されている画素領域と、前記画素が形成されていない非画素領域とが形成されており、
前記非画素領域のうち前記画素領域を挟んで対向する前記画素基板の両端側の位置にそれぞれ別々の前記信号読出回路が接続されており、
前記各画素は、前記画素領域を挟んで配置された前記信号読出回路のうち当該画素から近い側の信号読出回路に前記信号出力線を介して前記電流信号を出力することを特徴とする請求項1から4のいずれか1項に記載の放射線検出器。
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2018125738A (ja) * | 2017-02-01 | 2018-08-09 | シャープ株式会社 | 放射線検出器、およびスイッチ制御方法 |
US10886314B2 (en) | 2018-06-19 | 2021-01-05 | Sharp Kabushiki Kaisha | Radiation detector |
WO2021145254A1 (ja) * | 2020-01-16 | 2021-07-22 | 浜松ホトニクス株式会社 | 固体撮像装置およびアンプアレイ |
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CN109474795A (zh) * | 2018-10-31 | 2019-03-15 | 天津大学 | 一种基于跨导单元的低噪声像素电路结构 |
CN109541706B (zh) * | 2018-12-19 | 2020-11-10 | 地太科特电子制造(北京)有限公司 | 一种检测电路及射线探测器 |
CN110531401B (zh) * | 2019-09-11 | 2021-04-09 | 南华大学 | 核辐射探测器及核辐射探测方法 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006081241A (ja) * | 2004-09-07 | 2006-03-23 | Sony Corp | 電源制御方法および電源制御装置並びに電子機器および撮像装置 |
JP2010109564A (ja) * | 2008-10-29 | 2010-05-13 | Olympus Corp | 固体撮像装置、および、固体撮像方法 |
WO2013125113A1 (ja) * | 2012-02-22 | 2013-08-29 | 富士フイルム株式会社 | 放射線画像撮影制御装置、放射線画像撮影システム、放射線画像撮影装置の制御方法、及び放射線画像撮影制御プログラム |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10281870A (ja) | 1997-02-04 | 1998-10-23 | Matsushita Electron Corp | 物理量分布検知半導体装置およびその駆動方法 |
GB2343943B (en) * | 1998-11-18 | 2003-11-26 | Ericsson Telefon Ab L M | Detection circuit |
JP2001056382A (ja) * | 1999-06-07 | 2001-02-27 | Toshiba Corp | 放射線検出器及び放射線診断装置 |
WO2002067337A2 (en) | 2001-02-16 | 2002-08-29 | Ignis Innovation Inc. | Active pixel sensor for digital imaging |
JP2004037382A (ja) * | 2002-07-05 | 2004-02-05 | Toshiba Corp | 放射線検出器及び放射線診断装置 |
US20110168892A1 (en) | 2005-01-06 | 2011-07-14 | Koninklijke Philips Electronics N.V. | Pixel Implemented Current Amplifier |
US7211803B1 (en) * | 2006-04-24 | 2007-05-01 | Eastman Kodak Company | Wireless X-ray detector for a digital radiography system with remote X-ray event detection |
US8203111B2 (en) * | 2009-03-23 | 2012-06-19 | Tower Semiconductor Ltd. | CMOS image sensor pixel with an NMOS charge amplifier |
JP5564918B2 (ja) * | 2009-12-03 | 2014-08-06 | ソニー株式会社 | 撮像素子およびカメラシステム |
JP5962167B2 (ja) * | 2012-04-19 | 2016-08-03 | セイコーエプソン株式会社 | 検出回路、センサーデバイス及び電子機器 |
JP2014048171A (ja) * | 2012-08-31 | 2014-03-17 | Tele Systems:Kk | 放射線検出器に駆動用のバイアス電圧を供給する装置及びその方法 |
-
2016
- 2016-06-09 CN CN201680039157.2A patent/CN107710740B/zh active Active
- 2016-06-09 WO PCT/JP2016/067283 patent/WO2017010202A1/ja active Application Filing
- 2016-06-09 JP JP2017528333A patent/JP6483261B2/ja not_active Expired - Fee Related
- 2016-06-09 US US15/741,271 patent/US10209374B2/en active Active
- 2016-06-09 EP EP16824182.6A patent/EP3324609A4/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006081241A (ja) * | 2004-09-07 | 2006-03-23 | Sony Corp | 電源制御方法および電源制御装置並びに電子機器および撮像装置 |
JP2010109564A (ja) * | 2008-10-29 | 2010-05-13 | Olympus Corp | 固体撮像装置、および、固体撮像方法 |
WO2013125113A1 (ja) * | 2012-02-22 | 2013-08-29 | 富士フイルム株式会社 | 放射線画像撮影制御装置、放射線画像撮影システム、放射線画像撮影装置の制御方法、及び放射線画像撮影制御プログラム |
Non-Patent Citations (1)
Title |
---|
See also references of EP3324609A4 * |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2018125738A (ja) * | 2017-02-01 | 2018-08-09 | シャープ株式会社 | 放射線検出器、およびスイッチ制御方法 |
US10886314B2 (en) | 2018-06-19 | 2021-01-05 | Sharp Kabushiki Kaisha | Radiation detector |
WO2021145254A1 (ja) * | 2020-01-16 | 2021-07-22 | 浜松ホトニクス株式会社 | 固体撮像装置およびアンプアレイ |
GB2607502A (en) * | 2020-01-16 | 2022-12-07 | Hamamatsu Photonics Kk | Solid-state imaging device and amplifier array |
US11736835B2 (en) | 2020-01-16 | 2023-08-22 | Hamamatsu Photonics K.K. | Solid-state imaging device and amplifier array |
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