CN117939903A - Photoelectric conversion module, driving method, photoelectric detection circuit and detection device - Google Patents

Abstract

The embodiment of the application provides a photoelectric conversion module, a driving method, a photoelectric detection circuit and a detection device, wherein the photoelectric conversion module comprises: a photoelectric conversion unit for outputting photo-generated charges under irradiation of rays; the storage unit is electrically connected with the output end of the photoelectric conversion unit and is used for storing photo-generated charges; the first switch unit is used for outputting photo-generated charges stored in the storage unit to the signal transmission line; the source electrode of the second switch unit is electrically connected with the output end of the photoelectric conversion unit, the drain electrode of the second switch unit is electrically connected with the drain flow line, and the second switch unit is used for guiding dark state background charges output by the photoelectric conversion unit to the drain flow line. According to the technology provided by the application, the influence of dark state background charge on the detection result is reduced, and the detection precision of the photoelectric conversion module is improved.

Description

Photoelectric conversion module, driving method, photoelectric detection circuit and detection device

Technical Field

The present application relates to the field of detection technology, and in particular to a photoelectric conversion module, a driving method, a photoelectric detection circuit and a detection device.

Background technique

In the field of medical equipment, X-ray flat panel detectors have been widely used in various aspects of imaging diagnosis and treatment. At present, X-ray flat panel detectors mostly use indirect scintillator detectors, which use scintillator materials and photodiodes to convert X-rays into visible light through scintillators, and then use photodiodes to detect visible light. However, due to the loss of efficiency in the conversion of light, the required radiation dose needs to be increased accordingly, which is harmful to the health of users. In addition, in medical detection scenarios with high precision requirements such as breast detection, the number of pixels per unit area of X-ray flat panel detectors increases, and optical diffraction between adjacent pixels will cause signal crosstalk, thereby affecting the accuracy of detection.

A photodetector made of perovskite material is proposed in the related art. Compared with indirect scintillator detectors, photodetectors using perovskite materials have advantages in carrier transport characteristics and heavy atom composition architecture. Perovskite materials can directly convert X-rays into electrical signals, have the advantages of high sensitivity and low power consumption, and can be prepared using ultrasonic atomization spraying technology, and also have the advantage of simple manufacturing process. However, perovskite materials will generate a high dark background current during operation, resulting in a decrease in detection accuracy, thereby affecting the final imaging quality.

Summary of the invention

The embodiments of the present application provide a photoelectric conversion module, a driving method, a photoelectric detection circuit and a detection device to solve or alleviate one or more technical problems in the prior art.

In a first aspect, an embodiment of the present application provides a photoelectric conversion module, comprising: a photoelectric conversion unit, the photoelectric conversion unit being used to output photogenerated charges under irradiation of rays; a storage unit, the storage unit being electrically connected to the output end of the photoelectric conversion unit, and being used to store the photogenerated charges; a first switch unit, the source of the first switch unit being electrically connected to the storage unit, the drain of the first switch unit being electrically connected to a signal transmission line, the first switch unit being used to output the photogenerated charges stored in the storage unit to the signal transmission line; a second switch unit, the source of the second switch unit being electrically connected to the output end of the photoelectric conversion unit, the drain of the second switch unit being electrically connected to a leakage wiring, the second switch unit being used to direct the dark background charges output by the photoelectric conversion unit to the leakage wiring.

In one embodiment, the operating voltage of the photoelectric conversion unit is greater than the source voltage of the second switch unit, the gate voltage of the second switch unit is greater than the threshold voltage, and the voltage difference between the source and the drain of the second switch unit is greater than the threshold voltage, so that the second switch unit is in a saturation state when closed.

In one embodiment, a reference voltage is applied to the leakage current routing; the signal transmission line is electrically connected to the reset signal line through a reset switch, and when the reset switch is closed, the reset signal line outputs a reset signal to the signal transmission line; wherein the difference between the voltage value of the reset signal and the reference voltage is greater than the threshold voltage of the second switch unit, so that the difference between the source voltage and the drain voltage of the second switch unit is greater than the threshold voltage of the second switch unit.

In one implementation, the leakage line is electrically connected to a common ground terminal of the photoelectric conversion module.

In one embodiment, the photoelectric conversion module further includes: a readout integrated unit electrically connected to the signal transmission line, for collecting photogenerated charges and generating corresponding voltage signals.

In one embodiment, the second switch unit includes a super grain silicon thin film transistor, and a Schottky contact layer is provided between the source electrode and the semiconductor layer and between the drain electrode and the semiconductor layer of the super grain silicon thin film transistor.

In one embodiment, the photoelectric conversion unit includes a first electrode, a thin film response layer, a buffer layer and a second electrode stacked in sequence; wherein the first electrode is applied with a working voltage, the second electrode constitutes the output end of the photoelectric conversion unit, and the material of the thin film response layer includes a perovskite material.

In a second aspect, an embodiment of the present application provides a driving method of a photoelectric conversion module, which is applied to the photoelectric conversion module of any of the above embodiments of the present application, and the driving method includes:

Controlling the first switch unit and the reset switch to close, so as to reset the storage unit and the source of the second switch unit by a reset signal transmitted through the signal transmission line;

Control the first switch unit and the reset switch to be disconnected, and control the second switch unit to be closed, so that the second switch unit guides the dark background charge output by the photoelectric conversion unit to the leakage line, and the photoelectric conversion unit stores the photogenerated charge output by the photoelectric conversion unit under the irradiation of the radiation into the storage unit;

The first switch unit is controlled to be closed so as to output the photogenerated charges stored in the storage unit through the signal transmission line.

In the third aspect, an embodiment of the present application provides a photoelectric detection circuit, comprising a plurality of photoelectric conversion modules of the above-mentioned embodiments of the present application, wherein the plurality of photoelectric conversion modules are arrayed into a plurality of rows and a plurality of columns; wherein the gates of the first switch units of the plurality of photoelectric conversion modules in each row are electrically connected to the first drive line, respectively, and the gates of the second switch units of the plurality of photoelectric conversion modules in each row are electrically connected to the second drive line, respectively; the drains of the first switch units of the plurality of photoelectric conversion modules in each column are electrically connected to the signal transmission line, respectively, and the drains of the second switch units of the plurality of photoelectric conversion modules in each column are electrically connected to the leakage wiring, respectively.

In a fourth aspect, an embodiment of the present application provides a detection device, including the photoelectric detection circuit of the above-mentioned embodiment of the present application.

According to the photoelectric conversion module of the embodiment of the present application, a 2T1C circuit is set, that is, a first switch unit, a second switch unit and a storage unit are set, so that the photogenerated charge stored in the storage unit is output through the first switch unit, and the dark background charge generated by the photoelectric conversion unit is directed to the leakage wiring through the second switch unit, and the second switch unit can be in a saturated state when closed to output a constant current less than or equal to the dark background current. With such a setting, the dark background current generated by the photoelectric conversion unit can be shunted, and the dark background current is prevented from charging the storage unit and causing the storage unit to be saturated, ensuring that the photogenerated current can be stably stored in the storage unit and output, thereby reducing the influence of the dark background charge on the output of the photogenerated charge, and improving the detection accuracy and reliability of the photoelectric conversion module.

The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

FIG1 is a schematic diagram showing a circuit structure of an X-ray flat panel detector using a perovskite material as a photoelectric conversion unit in the related art;

FIG2 is a schematic diagram showing the structure of a photoelectric conversion module according to an embodiment of the present application;

FIG3 shows another schematic structural diagram of a photoelectric conversion module according to an embodiment of the present application;

FIG4 is a schematic structural diagram of a second switch unit of a photoelectric conversion module according to an embodiment of the present application;

FIG5 is a schematic diagram showing a comparison of output curves of a common TFT and a SGT TFT;

FIG6 is a schematic plan view of a photoelectric conversion module according to an embodiment of the present application;

Fig. 7 is a schematic cross-sectional view along the A-A' direction in Fig. 6;

FIG8 is a flow chart showing a method for driving a photoelectric conversion module according to an embodiment of the present application;

FIG9 shows a timing diagram of the operation of the photoelectric conversion module;

FIG10 is a schematic diagram showing the circuit structure of a photoelectric detection circuit;

FIG. 11 is a schematic diagram showing a method of preparing a perovskite thin film response layer using a spray coating process.

Detailed ways

In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

FIG1 shows a schematic diagram of the circuit structure of an X-ray flat panel detector 1′ using perovskite material as a photoelectric conversion unit 10′ in the related art. As shown in FIG1 , the X-ray flat panel detector 1′ includes a photoelectric conversion unit 10′ and a photoelectric conversion circuit. The photoelectric conversion unit 10′ is made of perovskite material, and the photoelectric conversion circuit includes a storage capacitor 20′ (Cst), a thin film transistor 30′ (SW TFT) and a readout integrated circuit 40′ (Readout Integrated Circuit, ROIC). Among them, the storage capacitor 20′ is electrically connected to the output end of the photoelectric conversion unit 10′; the source of the thin film transistor 30′ is electrically connected to the storage capacitor 20′, the drain of the thin film transistor 30′ is electrically connected to the readout integrated circuit 40′ through the detection data line 60′, and the gate of the thin film transistor 30′ is electrically connected to the scan signal line 50′ (Scan); the readout integrated circuit 40′ is reset by a reset signal (Vref1). During the operation of the X-ray flat panel detector 1', the photoelectric conversion unit 10' forms a vertical electric field under a certain bias voltage, and the photoelectric conversion unit 10' excites the perovskite material under X-ray irradiation to form photogenerated carriers, and the photogenerated carriers form a photogenerated current under the action of the electric field, and the photogenerated charges corresponding to the photogenerated current are stored in the storage capacitor 20'. The thin film transistor 30' is turned on by the row drive signal, and the photogenerated charges stored in the storage capacitor 20' are transmitted to the readout integrated circuit 40' through the detection data line 60'. The readout integrated circuit 40' converts the photogenerated charges into voltage signals and outputs them, and generates corresponding grayscale images according to different voltage signals for medical diagnosis.

It should be noted that the perovskite material will still generate current in the absence of radiation irradiation. This current is called dark background current, which is mainly caused by defects or impurities inside the material. After testing, it was found that the dark background current generated by the photoelectric conversion unit 10' is about 1.3E-10A, while the photogenerated current generated under X-ray irradiation with a dose of 500uGy/S is only 4E-11A. It can be seen that the dark background current generated by the photoelectric conversion unit 10' is one order of magnitude higher than the photogenerated current. In the process of storing charges in the storage capacitor 20', most of the stored charges are dark background charges, and this part of the charge is invalid for diagnostic signals and image grayscale display. Affected by the dark background charge, the size of the photogenerated charge cannot be accurately collected, resulting in low detection accuracy.

In response to the above-mentioned defects of X-ray flat-panel detectors that use perovskite materials as photoelectric conversion units in the related art, an embodiment of the present application provides a photoelectric conversion module that can reduce the influence of dark background charges on detection results and significantly improve the detection accuracy of the photoelectric conversion module.

FIG2 shows a schematic diagram of the structure of the photoelectric conversion module 1 of the embodiment of the present application. As shown in FIG2 , the photoelectric conversion module 1 of the embodiment of the present application includes a photoelectric conversion unit 10, a storage unit 20 (Cst), a first switch unit 30 (SGT TFT) and a second switch unit 40 (SW TFT). Specifically, the photoelectric conversion unit 10 is used to output photogenerated charges under the irradiation of rays. The storage unit 20 is electrically connected to the output end of the photoelectric conversion unit 10 and is used to store photogenerated charges. The source of the first switch unit 30 is electrically connected to the storage unit 20, and the drain of the first switch unit 30 is electrically connected to the signal transmission line 50 (Sensing Line). The first switch unit 30 is used to output the photogenerated charges stored in the storage unit 20 to the signal transmission line 50. The source of the second switch unit 40 is electrically connected to the output end of the photoelectric conversion unit 10, and the drain of the second switch unit 40 is electrically connected to the leakage wiring 60 (Vref2). The second switch unit 40 is used to guide the dark background charge output by the photoelectric conversion unit 10 to the leakage wiring 60, and shunt the dark background current I_SGT through the leakage wiring 60.

In an embodiment of the present application, the photoelectric conversion unit 10 may include a thin film response layer made of perovskite material. The thin film response layer forms photogenerated carriers under the irradiation of X-rays, and the photogenerated carriers form photogenerated current under the action of the electric field and are output.

Exemplarily, the storage unit 20 may adopt a storage capacitor. One end of the storage capacitor is electrically connected to the output end of the photoelectric conversion unit 10, and a connection node N1 is provided between the storage capacitor and the photoelectric conversion unit 10; the other end of the storage unit 20 is electrically connected to a common ground end. The first switch unit 30 and the second switch unit 40 may adopt thin film transistors, and the sources of the first switch unit 30 and the second switch unit 40 are respectively electrically connected to the connection node N1, so as to realize that the source of the first switch unit 30 is electrically connected to one end of the storage unit 20 and the source of the second switch unit 40 is electrically connected to the output end of the photoelectric conversion unit 10. In addition, the photoelectric conversion module 1 may further include a signal transmission line 50 and a leakage line 60, the signal transmission line 50 is electrically connected to the drain of the first switch unit 30, and the leakage line 60 is electrically connected to the drain of the second switch unit 40. The signal transmission line 50 is used to output the photogenerated charges stored in the storage unit 20 after the storage unit 20 completes the storage of the photogenerated charges and when the first switch unit 30 is in a closed state; the leakage line 60 is used to export the dark background charges generated by the photoelectric conversion unit 10 during the process of storing the photogenerated charges in the storage unit 20 and when the second switch unit 40 is in a closed state.

It should be noted that in the embodiment of the present application, the second switch unit 40 is in a saturated state when closed, so that the second switch unit 40 becomes a stable constant current source in the saturated state and outputs a constant current, wherein the constant current is less than or equal to the dark state background current generated by the photoelectric conversion unit 10.

The working principle of the photoelectric conversion module 1 of the embodiment of the present application is described below. The working process of the photoelectric conversion module 1 may include the following three stages:

(1) Reset stage: outputting a reset signal to the connection node N1 to reset the voltage of the connection node N1 to the first voltage;

(2) Charge storage stage: the first switch unit 30 is controlled to be disconnected and the second switch unit 40 is controlled to be closed, and the photoelectric conversion unit 10 generates photogenerated charges under X-ray irradiation and stores them in the storage unit 20. Meanwhile, the dark background charges generated by the photoelectric conversion unit 10 are discharged to the discharge wiring 60 through the second switch unit 40, so that the storage unit 20 can completely store the photogenerated charges.

(3) Charge output stage: the first switch unit 30 is controlled to be closed, so that the photogenerated charges stored in the storage unit 20 are output through the first switch unit 30 and the signal transmission line 50 .

According to the photoelectric conversion module 1 of the embodiment of the present application, a 2T1C circuit is set, that is, a first switch unit 30, a second switch unit 40 and a storage unit 20 are set, so that the photogenerated charges stored in the storage unit 20 are output through the first switch unit 30, and the dark background charges generated by the photoelectric conversion unit 10 are directed to the leakage wiring 60 through the second switch unit 40, and the second switch unit 40 can be in a saturated state when closed to output a constant current less than or equal to the dark background current. With such a setting, the dark background current generated by the photoelectric conversion unit 10 can be shunted, and the dark background current is prevented from charging the storage unit 20 and causing the storage unit 20 to be saturated, ensuring that the photogenerated current can be stably stored in the storage unit 20 and output, thereby reducing the influence of the dark background charge on the output of the photogenerated charge, and improving the detection accuracy and reliability of the photoelectric conversion module 1.

In one embodiment, the operating voltage of the photoelectric conversion unit 10 is greater than the source voltage of the second switch unit 40, the gate voltage of the second switch unit 40 is greater than the threshold voltage, and the voltage difference between the source and the drain of the second switch unit 40 is greater than the threshold voltage, so that the second switch unit 40 is in a saturation state when closed.

Exemplarily, the photoelectric conversion unit 10 has a top electrode and a bottom electrode, the top electrode is applied with a working voltage VDD, and the bottom electrode forms the output end of the photoelectric conversion unit 10 for outputting the photogenerated charge generated under the irradiation condition of the radiation. The gate of the second switch unit 40 is applied with a scan signal (Scan) so that the gate voltage Vg is greater than the threshold voltage Vth. In the reset stage of the photoelectric conversion module 1, under the condition that the first switch unit 30 is closed, a reset signal is input to the source of the second switch unit 40 through the signal transmission line 50 to adjust the source voltage Vs of the second switch unit 40. The leakage line 60 connected to the drain of the second switch unit 40 can be applied with a reference voltage to keep the drain voltage Vd of the second switch unit 40 constant. Among them, under the condition that the second switch unit 40 is closed, the gate voltage Vg＞threshold voltage Vdh, the working voltage VDD＞source voltage Vs＞drain voltage Vd, and the source voltage Vs-drain voltage Vd＞threshold voltage Vdh. In this way, the second switch unit 40 can be in a saturated state when closed.

It should be noted that the magnitude of the constant current output by the second switch unit 40 in the saturation state can be adjusted accordingly according to the magnitude of the gate voltage Vg, as long as the constant current output by the second switch unit 40 is less than or equal to the dark background current generated by the photoelectric conversion unit 10.

Optionally, the signal transmission line 50 is electrically connected to the reset signal line through a reset switch, and when the reset switch is closed, the reset signal line outputs a reset signal to the signal transmission line 50. A reference voltage is applied to the leakage line 60. It can be understood that, under the condition that the first switch unit 30 is closed, the reset signal transmitted by the signal transmission line 50 can be given to the source of the second switch unit 40 through the first switch unit 30, so that the source voltage Vs of the second switch unit 40 is adjusted to the voltage value Vref1 of the reset signal; the drain voltage Vd of the second switch unit 40 is equal to the reference voltage Vref2. Among them, the voltage value Vref1 of the reset signal is greater than the reference voltage Vref2, and the difference between the voltage value Vref1 of the reset signal and the reference voltage Vref2 is greater than the threshold voltage Vdh of the second switch unit 40, so that the difference between the source voltage Vs and the drain voltage Vd of the second switch unit 40 is greater than the threshold voltage Vdh of the second switch unit 40.

In one implementation, the leakage wiring 60 is electrically connected to the common ground terminal of the photoelectric conversion module 1 .

In this embodiment, by electrically connecting the leakage wiring 60 to the common ground terminal of the photoelectric conversion module 1 , the common voltage VSS can be used as a reference voltage applied to the leakage wiring 60 .

3, the drain of the second switch unit 40 is electrically connected to the common ground terminal of the photoelectric conversion module 1 through the leakage line 60, so that the drain voltage Vd of the second switch unit 40 and the common voltage VSS adopt the same potential. Such a configuration can reduce the circuit wiring of the photoelectric conversion module 1, reduce the crosstalk of the signal components, and improve the signal-to-noise ratio, thereby further improving the detection accuracy of the photoelectric conversion module 1.

In one embodiment, the photoelectric conversion module 1 further includes a readout integrated unit 70 electrically connected to the signal transmission line 50 for collecting photogenerated charges and generating corresponding voltage signals.

In the embodiment of the present application, the readout integrated circuit 70 may adopt a readout integrated circuit (ROIC). The readout integrated circuit may include a charge amplifier, an analog-to-digital converter, and a digital signal processor. The charge amplifier is used to amplify the photogenerated charge, the analog-to-digital converter is used to convert the analog signal into a digital signal, and the digital signal processor is used to filter, gain control, and data compress the digital signal. Among them, the digital signal may be a voltage signal, and the voltage signal output by the readout integrated unit 70 may form a grayscale image as a basis for medical diagnosis.

In one embodiment, the second switch unit 40 includes a super grain silicon thin film transistor (SGT TFT), and a Schottky contact layer 46 is disposed between the source electrode and the semiconductor layer and between the drain electrode and the semiconductor layer of the SGT TFT.

In the super-grained silicon thin film transistor, the Schottky contact layer 46 is the contact layer between the source and drain and the semiconductor. This contact mode is formed by a special band structure between the metal and the semiconductor, which is called a Schottky barrier. The characteristics of the Schottky contact layer 46 have an important influence on the performance of the TFT. For example, the height of the Schottky barrier will affect the ease with which current flows from the source or drain into the semiconductor, thereby affecting the switching characteristics and driving ability of the TFT. In the manufacturing process of the SGTTFT, by selecting appropriate metal materials and controlling the preparation conditions of the contact surface, the properties of the Schottky contact layer 46 can be optimized, thereby improving the performance of the TFT. For example, by selecting a metal material with a lower work function, the height of the Schottky barrier can be reduced and the current driving ability of the TFT can be improved.

FIG4 shows a schematic diagram of the structure of the second switch unit 40 of the photoelectric conversion module 1 of the embodiment of the present application. As shown in FIG4, exemplarily, the SGT TFT includes a gate metal 41, a gate insulating layer 42, an active layer 43, an interlayer dielectric layer 44 and a passivation layer 45 which are sequentially arranged on the substrate, and the source metal 47 and the drain metal 48 are respectively arranged on the passivation layer 45 and contact the active layer 43 through vias. Among them, a Schottky contact layer 46 is deposited between the source metal 47 and the drain metal 48 and the active layer 43, so that the source metal 47 and the drain metal 48 form a perfect Schottky contact with the active layer 43, and this contact makes the channel between the source metal 47 and the drain metal 48 have better instantaneous pinch-off and turn-on characteristics. FIG5 shows a schematic diagram of the output curve comparison of an ordinary TFT and an SGT TFT. As shown in FIG5, compared with an ordinary TFT, the SGT TFT has a lower saturation voltage, a wider saturation current and a wider stable voltage range, and also has a more stable small current output.

According to the above embodiment, by using SGT TFT as the second switch unit 40, the wider saturation voltage range, extremely small kink effect and low and stable saturation current of SGT TFT can be used as a constant current source to adjust the numerical range of the constant current output by the second switch unit 40, thereby further improving the detection accuracy of the photoelectric conversion module 1.

In one embodiment, the photoelectric conversion unit 10 includes a first electrode, a thin film response layer, a buffer layer 91 and a second electrode stacked in sequence. The first electrode is applied with a working voltage VDD, the second electrode constitutes an output end of the photoelectric conversion unit 10, and the material of the thin film response layer includes a perovskite material. The perovskite material may specifically include CsPbI ₂ Br or CsPbI ₃ , etc.

FIG6 shows a schematic plan view of the photoelectric conversion module 1 of the embodiment of the present application. As shown in FIG6, in some specific examples, the photoelectric conversion module 1 of the embodiment of the present application includes a photoelectric conversion unit 10, a storage unit 20 (not shown in the figure), a first switch unit 30 (SW TFT), a second switch unit 40 (SGT TFT), a signal transmission line 50, a leakage line 60, a first drive line 81 (Scan) and a second drive line 82 (Gate_s). Among them, the photoelectric conversion unit 10 is made of perovskite material, and the photoelectric conversion unit 10 is electrically connected to the storage unit 20 and has a connection node between the two. The first switch unit 30 can be specifically a SW TFT, and the second switch unit 40 can be specifically a SGT TFT. The source of the first switch unit 30 is electrically connected to the connection node, the drain of the first switch unit 30 is electrically connected to the signal transmission line 50, and the gate of the first switch unit 30 is electrically connected to the first drive line 81. The source of the second switch unit 40 is electrically connected to the connection node, the drain of the second switch unit 40 is electrically connected to the leakage line 60, and the gate of the second switch unit 40 is electrically connected to the second drive line 82. The first driving line 81 is used to output a first driving signal to the gate of the first switch unit 30 to drive the first switch unit 30 to close; the second driving line 82 is used to output a second driving signal to the gate of the second switch unit 40 to drive the second switch unit 40 to close. When the first switch unit 30 is closed, a reset signal can be output to the connection node through the signal transmission line 50 so that the source voltage of the second switch unit 40 reaches Vref1; the leakage line 60 is applied with a constant reference voltage Vref2 so that the drain voltage of the second switch unit 40 reaches Vref2. The working voltage Vdd of the photoelectric conversion unit 10> the source voltage Vref1 of the second switch unit 40> the drain voltage Vref2 of the second switch unit 40, the voltage of the second driving signal, that is, the gate voltage Vg of the second switch unit 40 is greater than the threshold voltage Vdh, and Vref1-Vref2>Vdh. In this way, the second switch unit 40 can be in a saturated state when closed, and the constant current output by the second switch unit 40 in the saturated state is less than or equal to the dark background current.

FIG7 shows a cross-sectional schematic diagram along the A-A' direction in FIG6. As shown in FIG7, in some examples, the photoelectric conversion module 1 includes a buffer layer 91, a gate wiring layer 92, a gate insulating layer 93, an active layer 94, a passivation layer 95, an interlayer dielectric layer 96, a source and drain wiring layer 97, a planarization layer 98, and a photoelectric conversion unit 10, and the photoelectric conversion unit 10 includes a stacked top electrode, a perovskite response layer, a pixel definition layer, and a bottom electrode. Among them, the source and drain of the first switch unit 30 (SW TFT) are formed in the source and drain wiring layer 97, and the gate of the first switch unit 30 is formed in the gate wiring layer 92; the source and drain of the second switch unit 40 are formed in the source and drain wiring layer 97, and the gate of the second switch unit 40 is formed in the gate wiring layer 92. In addition, the signal transmission line 50 and the leakage wiring 60 can be formed in the source and drain wiring layer 97.

The embodiment of the present application provides a driving method of a photoelectric conversion module, which is applied to the photoelectric conversion module of any of the above-mentioned embodiments of the present application. FIG8 shows a flow chart of the driving method of the photoelectric conversion module of the embodiment of the present application. As shown in FIG8, the driving method may include the following steps:

S101: Control the first switch unit and the reset switch to be closed, so as to reset the storage unit and the source of the second switch unit by a reset signal transmitted through the signal transmission line;

S102: Control the first switch unit and the reset switch to be disconnected, and control the second switch unit to be closed, so that the second switch unit guides the dark background charge output by the photoelectric conversion unit to the leakage wiring, and the photoelectric charge output by the photoelectric conversion unit under the irradiation of the radiation is stored in the storage unit;

S103: Control the first switch unit to be closed, so as to output the photogenerated charges stored in the storage unit through the signal transmission line.

In the embodiment of the present application, the voltage value of the reset signal is Vref1, and the source voltage Vs of the second switch unit after reset is equal to the voltage value Vref1 of the reset signal. A constant reference voltage Vref2 is applied to the leakage line, and the drain voltage Vd of the second switch unit is equal to the reference voltage Vref2. The gate voltage Vg of the second switch unit is greater than the threshold voltage Vdh, and the difference between the source voltage Vs and the drain voltage Vd is greater than the threshold voltage Vdh, so that the second switch unit is in a saturated state when closed, and the constant current output by the second switch unit in the saturated state is less than or equal to the dark background current output by the photoelectric conversion unit.

Preferably, the photoelectric conversion unit may use a thin film response layer made of a perovskite material. The second switch unit may use an SGT TFT.

FIG9 shows a working timing diagram of the photoelectric conversion module. As shown in FIG9 , the photoelectric conversion module may include the following three working stages:

(1) Reset stage (t1 to t2): the first switch unit and the reset switch are controlled to be closed, and the second switch unit is controlled to be opened, and a reset signal is output to the connection node between the storage unit and the photoelectric conversion unit through the signal transmission line, so that the voltage value of the connection node is reset to Vref1. At this time, the source voltage of the second switch unit is Vref1;

(2) Storage stage (t3 to t4): the second switch unit is controlled to be closed, and the first switch unit and the reset switch are opened, the photoelectric conversion unit generates photogenerated charges under X-ray irradiation, the photogenerated charges are stored in the storage unit, and the dark background charges generated by the photoelectric conversion unit are guided to the leakage wiring through the second switch unit;

(3) Output stage (after t4): the first switch unit is controlled to be closed, and the photogenerated charges stored in the storage unit enter the signal transmission line through the first switch unit and are transmitted to the ROIC electrically connected to the signal transmission line.

The embodiment of the present application provides a photoelectric detection circuit 100. FIG10 shows a schematic diagram of the circuit structure of the photoelectric detection circuit 100. As shown in FIG10, the photoelectric detection circuit 100 includes a plurality of photoelectric conversion modules 1 of the above-mentioned embodiment of the present application. The plurality of photoelectric conversion modules 1 are arrayed into a plurality of rows and a plurality of columns. Among them, the gates of the first switch units of the plurality of photoelectric conversion modules 1 in each row are respectively electrically connected to the first drive line 81 (Scan), and the gates of the second switch units of the plurality of photoelectric conversion modules 1 in each row are respectively electrically connected to the second drive line 82 (Gate_s); the drains of the first switch units of the plurality of photoelectric conversion modules 1 in each column are respectively electrically connected to the signal transmission line 50 (Sensing Line), and the drains of the second switch units of the plurality of photoelectric conversion modules 1 in each column are respectively electrically connected to the leakage wiring 60 (Vref2).

It should be noted that, in the embodiment of the present application, the thin film response layer of the photoelectric conversion unit used in the photoelectric conversion module 1 can be prepared using a perovskite material. Among them, the thin film response layer is prepared using a perovskite material, which can be prepared specifically by a spraying process. Figure 11 shows a schematic diagram of preparing a perovskite thin film response layer 104 using a spraying process. As shown in Figure 11, the spraying equipment may include a gas carrier hood 101 and an ultrasonic atomizing nozzle 102. The spraying equipment is driven by a mechanical stepping device to spray the perovskite material on the substrate 103 row by row, and finally form a perovskite thin film response layer 104. It should be noted that, affected by the preparation process, due to the differences between the thin film response layers of different rows, the size of the dark background current generated by the photoelectric conversion units of different rows is also different due to the existence of the differences. Therefore, the constant current output by the second switch unit of the photoelectric conversion module 1 in different rows in the saturated state can be adjusted accordingly according to the size of the dark background current output by the corresponding photoelectric conversion unit in practice, so that the constant current output by the second switch unit in the saturated state is less than or equal to the dark background current output by the photoelectric conversion unit. Specifically, the gate voltage of the second switch unit can be adjusted to adjust the magnitude of the constant current output by the second switch unit in the saturation state.

In a fourth aspect, an embodiment of the present application provides a detection device, including the photoelectric detection circuit of the above-mentioned embodiment of the present application.

In addition, other components of the detection device in the above embodiment can be adopted by various technical solutions known to ordinary technicians in this field now and in the future, and will not be described in detail here.

In the description of this specification, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

The disclosure above provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described above. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and/or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and/or settings discussed.

The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (10)

1. A photoelectric conversion module, comprising: A photoelectric conversion unit, the photoelectric conversion unit is used to output photogenerated charges under the irradiation of rays; A storage unit, the storage unit is electrically connected to the output end of the photoelectric conversion unit and is used to store the photogenerated charges; a first switch unit, wherein a source of the first switch unit is electrically connected to the storage unit, a drain of the first switch unit is electrically connected to the signal transmission line, and the first switch unit is used to output the photogenerated charges stored in the storage unit to the signal transmission line; A second switch unit, wherein the source of the second switch unit is electrically connected to the output end of the photoelectric conversion unit, the drain of the second switch unit is electrically connected to the leakage wiring, and the second switch unit is used to conduct the dark background charge output by the photoelectric conversion unit to the leakage wiring. 2. The photoelectric conversion module according to claim 1 is characterized in that the operating voltage of the photoelectric conversion unit is greater than the source voltage of the second switch unit, the gate voltage of the second switch unit is greater than the threshold voltage, and the voltage difference between the source and the drain of the second switch unit is greater than the threshold voltage, so that the second switch unit is in a saturation state when closed. 3. The photoelectric conversion module according to claim 2, characterized in that a reference voltage is applied to the leakage current line; the signal transmission line is electrically connected to the reset signal line through a reset switch, and when the reset switch is closed, the reset signal line outputs a reset signal to the signal transmission line; The difference between the voltage value of the reset signal and the reference voltage is greater than the threshold voltage of the second switch unit, so that the difference between the source voltage and the drain voltage of the second switch unit is greater than the threshold voltage of the second switch unit. 4 . The photoelectric conversion module according to claim 2 , wherein the leakage current line is electrically connected to a common ground terminal of the photoelectric conversion module. 5. The photoelectric conversion module according to claim 1, further comprising: The readout integrated unit is electrically connected to the signal transmission line and is used to collect the photogenerated charges and generate corresponding voltage signals. 6 . The photoelectric conversion module according to claim 1 , wherein the second switch unit comprises a super-grain silicon thin film transistor, and a Schottky contact layer is provided between the source electrode and the semiconductor layer and between the drain electrode and the semiconductor layer of the super-grain silicon thin film transistor. 7. The photoelectric conversion module according to any one of claims 1 to 6 is characterized in that the photoelectric conversion unit includes a first electrode, a thin film response layer, a buffer layer and a second electrode stacked in sequence; wherein a working voltage is applied to the first electrode, the second electrode constitutes the output end of the photoelectric conversion unit, and the material of the thin film response layer includes a perovskite material. 8. A method for driving a photoelectric conversion module, characterized in that it is applied to the photoelectric conversion module according to any one of claims 1 to 7, and the driving method comprises: Controlling the first switch unit and the reset switch to close, so as to reset the source of the storage unit and the second switch unit through the reset signal transmitted through the signal transmission line; Controlling the first switch unit and the reset switch to be disconnected, and controlling the second switch unit to be closed, so that the second switch unit guides the dark background charge output by the photoelectric conversion unit to the leakage wiring, and the photoelectric charge output by the photoelectric conversion unit under the irradiation of the radiation is stored in the storage unit; The first switch unit is controlled to be closed so as to output the photogenerated charges stored in the storage unit through the signal transmission line. 9. A photoelectric detection circuit, characterized in that it comprises a plurality of photoelectric conversion modules according to any one of claims 1 to 7, wherein the plurality of photoelectric conversion modules are arranged in an array in a plurality of rows and a plurality of columns; Among them, the gates of the first switch units of the multiple photoelectric conversion modules in each row are electrically connected to the first driving line, and the gates of the second switch units of the multiple photoelectric conversion modules in each row are electrically connected to the second driving line; the drains of the first switch units of the multiple photoelectric conversion modules in each column are electrically connected to the signal transmission line, and the drains of the second switch units of the multiple photoelectric conversion modules in each column are electrically connected to the leakage line. 10. A detection device, comprising the photoelectric detection circuit according to claim 9.