CN108205152B - A kind of pixel circuit, its driving method and X-ray detector - Google Patents
A kind of pixel circuit, its driving method and X-ray detector Download PDFInfo
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Abstract
The invention discloses a kind of pixel circuit, its driving method and X-ray detectors, comprising: initialization module, output module, output control module, photodiode and photodiode control module；In the inventive solutions, under conditions of output control module conducting, on the one hand the photoelectric current that photodiode generates controls output module conducting as control signal, on the other hand adjust the current value that output control module and output module of the first power supply signal end through being connected are exported；That is the photoelectric current and the first power supply signal end that the electric current of pixel circuit final output is generated by photodiode determine jointly, rather than the photoelectric current of directly output photoelectric diode generation, therefore the current output capability of pixel circuit is improved, and then signal-to-noise ratio is improved, improve picture quality.
Description
Technical Field
The invention relates to the technical field of display, in particular to a pixel circuit, a driving method thereof and an X-ray detector.
Background
The X-ray detector is widely applied to the fields of industrial nondestructive testing, container scanning, circuit board inspection, medical treatment, safety and the like, and has wide application prospect. They can be classified into Direct conversion (Direct DR) and Indirect conversion (Indirect DR) according to their operation principles. The indirect conversion type X-ray detector has the advantages of mature technology, relatively low cost, high Detection Quantum Efficiency (DQE), good reliability and the like, so that the indirect conversion type X-ray detector becomes the mainstream of the market.
At present, a pixel circuit of an indirect conversion type X-ray detector mainly includes a Thin Film Transistor (TFT) and a photodiode. Under the irradiation of X-rays, the scintillator layer or the phosphor layer converts X-ray photons into visible light, then the visible light is converted into an electric signal under the action of the photodiode to form a photocurrent, and finally the photocurrent is output through the thin film transistor to obtain a display image. However, since the photocurrent itself is weak, a good signal-to-noise ratio cannot be formed, resulting in poor image quality.
Disclosure of Invention
In view of the above, embodiments of the present invention provide a pixel circuit, a driving method thereof, and an X-ray detector, so as to improve a signal-to-noise ratio and improve image quality.
Therefore, an embodiment of the present invention provides a pixel circuit, including: the device comprises an initialization module, an output control module, a photodiode and a photodiode control module; wherein,
the control end of the initialization module is connected with the first control signal end, the input end of the initialization module is connected with the initialization signal end, and the output end of the initialization module is connected with the first node; the initialization module is configured to provide a signal of the initialization signal terminal to the first node under the control of the first control signal terminal;
the anode of the photodiode is connected with an enabling signal end, the cathode of the photodiode is connected with the input end of the photodiode control module, the control end of the photodiode control module is connected with a second control signal end, and the output end of the photodiode control module is connected with the first node; the photodiode control module is used for providing the photocurrent of the photodiode to the first node under the control of the second control signal end;
the control end of the output module is connected with the first node, the input end of the output module is connected with the second node, and the output end of the output module is connected with the third node; the control end of the output control module is connected with the third control signal end, the first input end is connected with the first power supply signal end, the second input end is connected with the third node, the first output end is connected with the second node, and the second output end is connected with the signal reading line; the output module outputs a current determined by the first node and the first power signal terminal to the signal reading line through the turned-on output control module under the control of the first node.
In a possible implementation manner, in the pixel circuit provided in an embodiment of the present invention, the initialization module includes: a first switching transistor;
the grid electrode of the first switch transistor is connected with the first control signal end, the first pole of the first switch transistor is connected with the initialization signal end, and the second pole of the first switch transistor is connected with the first node.
In a possible implementation manner, in the pixel circuit provided in an embodiment of the present invention, the photodiode control module includes: a second switching transistor;
and the grid electrode of the second switching transistor is connected with the second control signal end, the first pole of the second switching transistor is connected with the cathode of the photodiode, and the second pole of the second switching transistor is connected with the first node.
In a possible implementation manner, in the foregoing pixel circuit provided in an embodiment of the present invention, the output module includes: a third switching transistor and a capacitor; wherein,
the grid electrode of the third switching transistor is connected with the first node, the first pole of the third switching transistor is connected with the second node, and the second pole of the third switching transistor is connected with the third node;
one end of the capacitor is connected with the first node, and the other end of the capacitor is connected with the second node.
In a possible implementation manner, in the foregoing pixel circuit provided in an embodiment of the present invention, the output control module includes: a fourth switching transistor and a fifth switching transistor; wherein,
a grid electrode of the fourth switching transistor is connected with the third control signal end, a first electrode of the fourth switching transistor is connected with the first power supply signal end, and a second electrode of the fourth switching transistor is connected with the second node;
a gate of the fifth switching transistor is connected to the third control signal terminal, a first pole thereof is connected to the third node, and a second pole thereof is connected to the signal reading line.
In a possible implementation manner, in the pixel circuit provided in the embodiment of the present invention, the pixel circuit further includes: a discharge module;
the control end of the discharging module is connected with the fourth control signal end, the first input end is connected with the second power supply signal end, the second input end is connected with the first node, the first output end is connected with the second node, and the second output end is connected with the third node; and the discharging module is used for discharging the output module under the control of the fourth control signal end.
In a possible implementation manner, in the above pixel circuit provided in an embodiment of the present invention, the discharging module includes: a sixth switching transistor and a seventh switching transistor; wherein,
a grid electrode of the sixth switching transistor is connected with the fourth control signal end, a first pole is connected with the second power supply signal end, and a second pole is connected with the second node;
and the grid electrode of the seventh switching transistor is connected with the fourth control signal end, the first pole of the seventh switching transistor is connected with the first node, and the second pole of the seventh switching transistor is connected with the third node.
Correspondingly, an embodiment of the present invention further provides a driving method of the pixel circuit, including:
in the first stage, an initialization module provides a signal of an initialization signal end to a first node under the control of a first control signal end;
in the second stage, the photodiode control module provides the photocurrent of the photodiode to the first node under the control of a second control signal end;
and in the third stage, the output control module is conducted under the control of a third control signal end, and the output module outputs current determined by the first node and the first power supply signal end to the signal reading line through the conducted output control module under the control of the first node.
In a possible implementation manner, in the foregoing driving method provided by the embodiment of the present invention, in the first stage, after the initialization module provides the signal of the initialization signal terminal to the first node under the control of the first control signal terminal, and in the second stage, before the photodiode control module provides the photocurrent of the photodiode to the first node under the control of the second control signal terminal, the method further includes:
and in the discharging stage, the discharging module discharges the output module under the control of the fourth control signal end.
Based on the same inventive concept, the embodiment of the invention also provides an X-ray detector, which comprises the pixel circuit.
The invention has the following beneficial effects:
the pixel circuit, the driving method thereof and the X-ray detector provided by the embodiment of the invention comprise the following steps: the device comprises an initialization module, an output control module, a photodiode and a photodiode control module; the control end of the initialization module is connected with the first control signal end, the input end of the initialization module is connected with the initialization signal end, and the output end of the initialization module is connected with the first node; the initialization module is used for providing a signal of an initialization signal end to a first node under the control of a first control signal end; the anode of the photodiode is connected with the enable signal end, the cathode of the photodiode is connected with the input end of the photodiode control module, the control end of the photodiode control module is connected with the second control signal end, and the output end of the photodiode control module is connected with the first node; the photodiode control module is used for providing the photocurrent of the photodiode to a first node under the control of a second control signal end; the control end of the output module is connected with the first node, the input end of the output module is connected with the second node, and the output end of the output module is connected with the third node; the control end of the output control module is connected with the third control signal end, the first input end is connected with the first power supply signal end, the second input end is connected with the third node, the first output end is connected with the second node, and the second output end is connected with the signal reading line; the output module outputs current determined by the first node and the first power signal end to the signal reading line through the conducted output control module under the control of the first node. In the technical scheme of the invention, under the condition that the output control module is conducted, the photocurrent generated by the photodiode is used as a control signal, on one hand, the conduction of the output module is controlled, and on the other hand, the current value output by the conducted output control module and the output module at the first power signal end is adjusted; that is to say, the final output current of the pixel circuit is determined by the photocurrent generated by the photodiode and the first power signal terminal together, rather than the photocurrent generated by the photodiode, so that the current output capability of the pixel circuit is improved, the signal-to-noise ratio is further improved, and the image quality is improved.
Drawings
Fig. 1 is a schematic structural diagram of a pixel circuit according to an embodiment of the present invention;
fig. 2 is a flowchart of a driving method of the pixel circuit shown in fig. 1;
fig. 3 is a detailed structural schematic diagram of the pixel circuit shown in fig. 1;
fig. 4 is an operation timing diagram of the pixel circuit shown in fig. 3;
fig. 5 is a second schematic structural diagram of a pixel circuit according to an embodiment of the invention;
fig. 6 is a flowchart of a driving method of the pixel circuit shown in fig. 5;
fig. 7 is a specific structural schematic diagram of the pixel circuit shown in fig. 5;
fig. 8 is an operation timing diagram of the pixel circuit shown in fig. 7.
Detailed Description
Specific embodiments of a pixel circuit, a driving method thereof, and an X-ray detector according to an embodiment of the present invention are described in detail below with reference to the accompanying drawings. It should be noted that the embodiments described in this specification are only a part of the embodiments of the present invention, and not all embodiments; and in case of conflict, the embodiments and features of the embodiments in the present application may be combined with each other; moreover, all other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative effort belong to the protection scope of the present invention.
The pixel circuit provided by the invention, as shown in fig. 1, includes: the device comprises an initialization module 101, a photodiode PIN, a photodiode control module 102, an output module 103 and an output control module 104; the control end of the initialization module 101 is connected to the first control signal end EN1, the input end is connected to the initialization signal end Init, and the output end is connected to the first node P1; an initialization module 101, configured to provide a signal of an initialization signal terminal Init to a first node P1 under the control of a first control signal terminal EN 1;
the anode of the photodiode PIN is connected with the enable signal end Vbias, the cathode of the photodiode PIN is connected with the input end of the photodiode control module 102, the control end of the photodiode control module 102 is connected with the second control signal end EN2, and the output end of the photodiode control module is connected with the first node P1; a photodiode control module 102 for providing the photocurrent of the photodiode PIN to the first node P1 under the control of a second control signal terminal EN 2;
the control end of the output module 103 is connected with the first node P1, the input end is connected with the second node P2, and the output end is connected with the third node P3; a control end of the output control module 104 is connected to the third control signal end Sel, a first input end is connected to the first power signal end Vdd, a second input end is connected to the third node P3, a first output end is connected to the second node P2, and a second output end is connected to the signal reading line L; the output block 103 outputs a current determined by the first node P1 in common with the first power signal terminal Vdd to the signal read line L through the turned-on output control block 104 under the control of the first node P1.
In the pixel circuit shown in fig. 1, photocurrent generated by the photodiode PIN is used as a control signal, on one hand, the output module 103 can be controlled to be turned on, and on the other hand, a current value of the first power signal terminal Vdd directly outputted through the output control module 104 and the output module 103 can be adjusted, that is, the current finally outputted by the pixel circuit is determined by the photocurrent generated by the photodiode PIN and the first power signal terminal Vdd instead of directly outputting the photocurrent generated by the photodiode PIN, wherein the first power signal terminal Vdd is a stable high level, so that the current output capability of the pixel circuit is improved, the signal-to-noise ratio is further improved, and the image quality is improved.
Correspondingly, for the pixel circuit shown in fig. 1, the present invention provides a driving method, as shown in fig. 2, which specifically includes the following steps:
s201, in the first stage, an initialization module provides a signal of an initialization signal end to a first node under the control of a first control signal end;
s202, in the second stage, the photoelectric diode control module provides the photoelectric current of the photoelectric diode to a first node under the control of a second control signal end;
and S203, in the third stage, the output control module is conducted under the control of the third control signal end, and the output module outputs the current determined by the first node and the first power signal end to the signal reading line through the conducted output control module under the control of the first node.
In order to better understand the structure and the operation principle of the pixel circuit shown in fig. 1, a detailed description will be given below with reference to a specific embodiment.
Fig. 3 is a specific embodiment of the pixel circuit shown in fig. 1. As shown in fig. 3, the initialization module 101 includes: a first switching transistor T1; and the gate of the first switching transistor T1 is connected to the first control signal terminal EN1, the first pole is connected to the initialization signal terminal Init, and the second pole is connected to the first node P1.
A photodiode control module 102 comprising: a second switching transistor T2; and the gate of the second switching transistor T2 is connected to the second control signal terminal EN2, the first pole is connected to the cathode of the photodiode PIN, and the second pole is connected to the first node P1.
An output module 103 comprising: a third switching transistor T3 and a capacitor C; wherein the gate of the third switching transistor T3 is connected to the first node P1, the first pole is connected to the second node P2, and the second pole is connected to the third node P3; the capacitor C has one terminal connected to the first node P1 and the other terminal connected to the second node P2.
An output control module 104, comprising: a fourth switching transistor T4 and a fifth switching transistor T5; a gate of the fourth switching transistor T4 is connected to the third control signal terminal Sel, a first electrode is connected to the first power signal terminal Vdd, and a second electrode is connected to the second node P2; the gate of the fifth switching transistor T5 is connected to the third control signal terminal Sel, the first pole is connected to the third node P3, and the second pole is connected to the signal read line L.
It should be noted that the above is only an example of the specific structure of each module in the pixel circuit, and actually, the specific structure of each module is not limited to the above structure provided by the embodiment of the present invention, and may be other structures known to those skilled in the art.
In addition, each of the switching transistors mentioned in the above embodiments of the present invention may be a Thin Film Transistor (TFT) or a Metal oxide semiconductor field effect Transistor (MOS), and is not limited herein. The switching transistors may be all P-type transistors or all N-type transistors, and are not limited herein. The first pole and the second pole of the switching transistors are respectively a source electrode and a drain electrode; in practical applications, the functions of the first pole and the second pole can be interchanged without specific distinction according to the type of the switching transistor and the difference of the input signal.
The working process of the pixel circuit shown in fig. 3 is described below by taking an example in which each switching transistor is an N-type transistor, and each N-type transistor is turned on under the action of a high level and turned off under the action of a low level. The corresponding operation timing chart is shown in fig. 4, and specifically, the first phase t1, the second phase t2, and the third phase t3 in the operation timing chart shown in fig. 4 are taken as examples for detailed description.
First stage t 1: the first control signal terminal EN1 is high, the second control signal terminal EN2 is low, and the third control signal terminal Sel is low.
The first switching transistor T1 is turned on by the high level of the first control signal terminal EN1, and the high level of the initialization signal terminal Init is written into the first node P1 through the turned-on first switching transistor T1, thereby realizing initialization of the first node P1. The second switching transistor T2 is turned off by the low level of the second control signal terminal EN2, and does not affect the potential of the first node P1. Since the high level of the initialization signal terminal Init is written in the first node P1, the potential of the first node P1 is high, the capacitor C starts to be charged, and the third switching transistor T3 is turned on, but since the third control signal terminal Sel is low, the fourth switching transistor T4 and the fifth switching transistor T5 are both in an off state, and the pixel circuit does not have any output.
Second stage t 2: the first control signal terminal EN1 is at low level, the second control signal terminal EN2 is at high level, and the third control signal terminal Sel is at low level.
The first switch transistor T1 is turned off because the first control signal terminal EN1 is at a low level. The second control signal terminal EN2 is at a high level, the second switch transistor T2 is turned on, the capacitor C discharges through the second switch transistor T2 and the photodiode PIN, resulting in a decrease in voltage across the capacitor C, but since the photocurrent generated by the photoelectric effect of the photodiode PIN itself is affected by the fluorescence intensity, the remaining voltage of the capacitor C is different under different fluorescence intensities, and at this time, the third switch transistor T3 is still in an on state. Since the third control signal terminal Sel is at a low level, the fourth switching transistor T4 and the fifth switching transistor T5 are both in an off state, and thus the pixel circuit does not have any output in the second stage.
Third stage t 3: the first control signal terminal EN1 is low, the second control signal terminal EN2 is low, and the third control signal terminal Sel is high.
The first switching transistor T1 remains turned off because the first control signal terminal EN1 is at a low level; the second control signal terminal EN2 is low, and the second switching transistor T2 is also turned off. The third control signal terminal Sel is at a high level, the fourth switching transistor T4 and the fifth switching transistor T5 are both turned on, and since the third switching transistor T3 is kept at an on state all the time, the high level of the first power signal terminal Vdd can be outputted to the signal reading line L through the turned-on fourth switching transistor T4, the turned-on third switching transistor T3 and the turned-on fifth switching transistor T5, and the magnitude of the output current depends on the voltage of the capacitor C remaining in the second stage and the high level of the first power signal terminal Vdd.
Because the photocurrent generated by the photodiode PIN determines the magnitude of the residual voltage of the capacitor C in the second stage, the opening degree of the third switching transistor T3 is controlled by the residual voltage of the capacitor C in the second stage in the third stage, which is equivalent to the opening degree of the third switching transistor T3 controlled by the photocurrent generated by the photodiode PIN, so that the high level of the first power signal terminal Vdd can be output by the opened third switching transistor T3, and the larger the opening degree of the third switching transistor T3 controlled by the photocurrent generated by the photodiode PIN is, the larger the current output by the third switching transistor T3 is, the current output capability of the pixel circuit is improved, the signal-to-noise ratio is improved, and the image quality is improved.
In the subsequent time period, the pixel circuit repeats the operation process from t1 to t 3.
As can be seen from the above description, in the pixel circuit shown in fig. 1, when the photodiode control module 102 supplies the photocurrent of the photodiode PIN to the first node P1 under the control of the second control signal terminal EN2 in the second stage, the output module 103 discharges through the photodiode PIN and the photodiode control module 102. It is considered that there may be a case where the output block 103 is charged by the photodiode PIN and the photodiode control block 102 when the photodiode control block 102 supplies the photocurrent of the photodiode PIN to the first node P1 under the control of the second control signal terminal EN 2. Accordingly, the present invention provides another pixel circuit, as shown in fig. 5, including: an initialization module 101, a photodiode PIN, a photodiode control module 102, an output module 103, an output control module 104, and a discharge module 105. Because the discharging module 105 is added to the pixel circuit shown in fig. 1, only the discharging module 105 is described in detail below, and the specific implementation of the remaining modules can refer to the pixel circuit shown in fig. 1, and repeated parts are not described again.
As shown in fig. 5, the control terminal of the discharging module 105 is connected to the fourth control signal terminal EN3, the first input terminal is connected to the second power signal terminal Vss, the second input terminal is connected to the first node P1, the first output terminal is connected to the second node P2, and the second output terminal is connected to the third node P3; for discharging the output module 103 under the control of the fourth control signal terminal EN 3.
Like the pixel circuit shown in fig. 1, the pixel circuit shown in fig. 5 controls the output module 103 to be turned on by using photocurrent generated by the photodiode PIN as a control signal, and uses the first power signal terminal Vdd to directly output current through the output control module 104 and the output module 103, so that the current output capability of the pixel circuit is improved, the signal-to-noise ratio is further improved, and the image quality is improved.
In contrast, in the pixel circuit shown in fig. 1, the output module 103 discharges through the photodiode PIN and the photodiode control module 102, and the output module 103 is ensured to be in an on state. In the pixel circuit shown in fig. 5, the output module 103 is first discharged through the discharging module 105, so that the output module 103 is in a closed state, and then charged through the photodiode PIN and the photodiode control module 102, so that the output module 103 is in an open state.
Accordingly, the present invention provides a method for driving the pixel circuit shown in fig. 5, as shown in fig. 6, specifically including:
s201, in the first stage, an initialization module provides a signal of an initialization signal end to a first node under the control of a first control signal end;
s601, in a discharging stage, the discharging module discharges the output module under the control of the fourth control signal end;
s202, in the second stage, the photoelectric diode control module provides the photoelectric current of the photoelectric diode to a first node under the control of a second control signal end;
and S203, in the third stage, the output control module is conducted under the control of the third control signal end, and the output module outputs the current determined by the first node and the first power signal end to the signal reading line through the conducted output control module under the control of the first node.
In order to better understand the structure and the operation principle of the pixel circuit shown in fig. 5, a detailed description will be given below with reference to a specific embodiment.
Fig. 7 is a specific embodiment of the pixel circuit shown in fig. 5 described above. Since the specific structure of the discharge module 105 is added in fig. 7 compared to fig. 3, only the discharge module 105 will be described in detail below, and the specific structure of each of the other modules may refer to the pixel circuit shown in fig. 3, and repeated parts are not described again.
As shown in fig. 7, the discharging module 105 includes: a sixth switching transistor T6 and a seventh switching transistor T7; a gate of the sixth switching transistor T6 is connected to the fourth control signal terminal EN3, a first pole thereof is connected to the second power signal terminal Vss, and a second pole thereof is connected to the second node P2; the seventh switching transistor T7 has a gate connected to the fourth control signal terminal EN3, a first pole connected to the first node P1, and a second pole connected to the third node P3.
It should be noted that the above is only an example of the specific structure of the discharge module 105, and actually, the specific structure of the discharge module 105 is not limited to the above structure provided by the embodiment of the present invention, and may be other structures known to those skilled in the art. The functions of the sixth switching transistor T6 and the seventh switching transistor T7, the first pole and the second pole of the discharging module 105 may refer to the first switching transistor T1 to the fifth switching transistor T5.
The operation process of the pixel circuit shown in fig. 7 is described below by taking an example in which each switching transistor is an N-type transistor, and each N-type transistor is turned on under the action of a high level and turned off under the action of a low level. The corresponding operation timing chart is shown in fig. 8, and specifically, the first phase t1, the discharging phase t, the second phase t2, and the third phase t3 in the operation timing chart shown in fig. 8 are taken as examples for detailed description.
First stage t 1: the first control signal terminal EN1 is high, the second control signal terminal EN2 is low, the third control signal terminal Sel is low, and the fourth control signal terminal EN3 is low.
The first switching transistor T1 is turned on by the high level of the first control signal terminal EN1, and the high level of the initialization signal terminal Init is written into the first node P1 through the turned-on first switching transistor T1, thereby realizing initialization of the first node P1. The second switching transistor T2 is turned off by the low level of the second control signal terminal EN2, and does not affect the potential of the first node P1. The fourth control signal terminal EN3 is low, and the sixth switching transistor T6 and the seventh switching transistor T7 are both turned off, so that the voltage across the capacitor C is not affected. Since the high level of the initialization signal terminal Init is written in the first node P1, the potential of the first node P1 is high, the capacitor C starts to be charged, and the third switching transistor T3 is turned on; however, since the third control signal terminal Sel is at a low level, the fourth switching transistor T4 and the fifth switching transistor T5 are both in an off state, and the pixel circuit does not have any output.
And (3) a discharge stage t: the first control signal terminal EN1 is at low level, the second control signal terminal EN2 is at low level, the third control signal terminal Sel is at low level, and the fourth control signal terminal EN3 is at high level.
The fourth control signal terminal EN3 is at a high level, the sixth switching transistor T6 and the seventh switching transistor T7 are turned on, and the low level of the second power signal terminal Vss affects the voltage across the capacitor C, specifically, the capacitor C is discharged through the sixth switching transistor T6 and the seventh switching transistor T7, resulting in the voltage across the capacitor C decreasing until the voltage difference across the capacitor C is equal to the threshold voltage of the third switching transistor T3, at which time the third switching transistor T3 is turned off.
Second stage t 2: the first control signal terminal EN1 is at low level, the second control signal terminal EN2 is at high level, the third control signal terminal Sel is at low level, and the fourth control signal terminal EN3 is at low level.
The second control signal terminal EN2 is at a high level, the second switching transistor T2 is turned on, the capacitor C is charged through the second switching transistor T2 and the photodiode PIN, resulting in an increase in the voltage across the capacitor C, but since the magnitude of the photocurrent generated by the photoelectric effect of the photodiode PIN is affected by the intensity of the fluorescent light, the increase in the voltage across the capacitor C is different under different intensities of fluorescent light, and finally the third switching transistor T3 is turned on.
Third stage t 3: the first control signal terminal EN1 is at low level, the second control signal terminal EN2 is at low level, the third control signal terminal Sel is at high level, and the fourth control signal terminal EN3 is at low level.
The third control signal terminal Sel is at a high level, the fourth switching transistor T4 and the fifth switching transistor T5 are both turned on, and the third switching transistor T3 is turned on, so that the high level of the first power signal terminal Vdd can be outputted to the signal reading line L through the turned-on fourth switching transistor T4, third switching transistor T3 and fifth switching transistor T5, and the magnitude of the output current depends on the voltage of the capacitor C at the end of the second stage and the high level of the first power signal terminal Vdd.
Because the photocurrent generated by the photodiode PIN determines the voltage of the capacitor C at the end of the second stage, the voltage of the capacitor C at the end of the second stage controls the turn-on degree of the third switching transistor T3 in the third stage, which is equivalent to the photocurrent generated by the photodiode PIN controlling the turn-on degree of the third switching transistor T3, so that the high level of the first power signal terminal Vdd can perform current output through the turned-on third switching transistor T3, and the larger the photocurrent generated by the photodiode PIN controls the turn-on degree of the third switching transistor T3, the larger the current output through the third switching transistor T3 is, the current output capability of the pixel circuit is improved, the signal-to-noise ratio is improved, and the image quality is improved.
In the subsequent time period, the pixel circuit repeats the operation process from t1 to t 3.
Based on the same inventive concept, an embodiment of the present invention provides an X-ray detector, including the pixel circuit, and as a problem solving principle of the X-ray detector is similar to a problem solving principle of the pixel circuit, implementation of the X-ray detector provided by the embodiment of the present invention may refer to implementation of the pixel circuit provided by the embodiment of the present invention, and repeated details are not repeated.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A pixel circuit, comprising: the device comprises an initialization module, an output control module, a photodiode and a photodiode control module; wherein,
the control end of the initialization module is connected with the first control signal end, the input end of the initialization module is connected with the initialization signal end, and the output end of the initialization module is connected with the first node; the initialization module is configured to provide a signal of the initialization signal terminal to the first node under the control of the first control signal terminal;
the anode of the photodiode is connected with an enabling signal end, the cathode of the photodiode is connected with the input end of the photodiode control module, the control end of the photodiode control module is connected with a second control signal end, and the output end of the photodiode control module is connected with the first node; the photodiode control module is used for providing the photocurrent of the photodiode to the first node under the control of the second control signal end;
the control end of the output module is connected with the first node, the input end of the output module is connected with the second node, and the output end of the output module is connected with the third node; the control end of the output control module is connected with the third control signal end, the first input end is connected with the first power supply signal end, the second input end is connected with the third node, the first output end is connected with the second node, and the second output end is connected with the signal reading line; the output module outputs a current determined by the first node and the first power signal terminal to the signal reading line through the turned-on output control module under the control of the first node.
2. A picture element circuit as claimed in claim 1, wherein the initialization module comprises: a first switching transistor;
the grid electrode of the first switch transistor is connected with the first control signal end, the first pole of the first switch transistor is connected with the initialization signal end, and the second pole of the first switch transistor is connected with the first node.
3. A pixel circuit as claimed in claim 1, wherein the photodiode control module includes: a second switching transistor;
and the grid electrode of the second switching transistor is connected with the second control signal end, the first pole of the second switching transistor is connected with the cathode of the photodiode, and the second pole of the second switching transistor is connected with the first node.
4. A picture element circuit as claimed in claim 1, wherein the output module comprises: a third switching transistor and a capacitor; wherein,
the grid electrode of the third switching transistor is connected with the first node, the first pole of the third switching transistor is connected with the second node, and the second pole of the third switching transistor is connected with the third node;
one end of the capacitor is connected with the first node, and the other end of the capacitor is connected with the second node.
5. A picture element circuit as claimed in claim 1, wherein the output control module comprises: a fourth switching transistor and a fifth switching transistor; wherein,
a grid electrode of the fourth switching transistor is connected with the third control signal end, a first electrode of the fourth switching transistor is connected with the first power supply signal end, and a second electrode of the fourth switching transistor is connected with the second node;
a gate of the fifth switching transistor is connected to the third control signal terminal, a first pole thereof is connected to the third node, and a second pole thereof is connected to the signal reading line.
6. A picture element circuit as claimed in claim 1, further comprising: a discharge module;
the control end of the discharging module is connected with the fourth control signal end, the first input end is connected with the second power supply signal end, the second input end is connected with the first node, the first output end is connected with the second node, and the second output end is connected with the third node; and the discharging module is used for discharging the output module under the control of the fourth control signal end.
7. A picture element circuit as claimed in claim 6, wherein the discharging module comprises: a sixth switching transistor and a seventh switching transistor; wherein,
a grid electrode of the sixth switching transistor is connected with the fourth control signal end, a first pole is connected with the second power supply signal end, and a second pole is connected with the second node;
and the grid electrode of the seventh switching transistor is connected with the fourth control signal end, the first pole of the seventh switching transistor is connected with the first node, and the second pole of the seventh switching transistor is connected with the third node.
8. A driving method of a picture element circuit according to any one of claims 1 to 7, comprising:
in the first stage, an initialization module provides a signal of an initialization signal end to a first node under the control of a first control signal end;
in the second stage, the photodiode control module provides the photocurrent of the photodiode to the first node under the control of a second control signal end;
and in the third stage, the output control module is conducted under the control of a third control signal end, and the output module outputs current determined by the first node and the first power supply signal end to the signal reading line through the conducted output control module under the control of the first node.
9. The driving method as claimed in claim 8, wherein after the initialization module supplies the signal of the initialization signal terminal to the first node under the control of the first control signal terminal in the first stage, and before the photodiode control module supplies the photocurrent of the photodiode to the first node under the control of the second control signal terminal in the second stage, further comprising:
and in the discharging stage, the discharging module discharges the output module under the control of the fourth control signal end.
10. An X-ray detector characterized by comprising the pixel circuit according to any one of claims 1 to 7.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1806865A (en) * | 2005-12-17 | 2006-07-26 | 重庆大学 | Retina electrostimulation pixel circuit for artificial vision rehabilitation |
| WO2016132329A1 (en) * | 2015-02-19 | 2016-08-25 | Fondazione Bruno Kessler | Circuit architecture of an improved pixel for detecting and calculating the number of photons |
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| KR20050107517A (en) * | 2003-03-12 | 2005-11-11 | 코닌클리케 필립스 일렉트로닉스 엔.브이. | Light emissive active matrix display devices with optical feedback effective on the timing to counteract ageing |
| US7652704B2 (en) * | 2004-08-25 | 2010-01-26 | Aptina Imaging Corporation | Pixel for boosting pixel reset voltage |
| KR100744119B1 (en) * | 2005-12-24 | 2007-08-01 | 삼성전자주식회사 | Pixel circuit having a boosting capacitor, driving method of the pixel circuit and image sensor comprising the pixel circuit |
| US8546765B2 (en) * | 2008-06-26 | 2013-10-01 | Trixell | High dynamic range X-ray detector with improved signal to noise ratio |
| FR3017019A1 (en) * | 2014-01-24 | 2015-07-31 | St Microelectronics Grenoble 2 | |
| CN104867431B (en) * | 2015-06-12 | 2019-06-21 | 京东方科技集团股份有限公司 | A kind of pixel circuit and its driving method, detector |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1806865A (en) * | 2005-12-17 | 2006-07-26 | 重庆大学 | Retina electrostimulation pixel circuit for artificial vision rehabilitation |
| WO2016132329A1 (en) * | 2015-02-19 | 2016-08-25 | Fondazione Bruno Kessler | Circuit architecture of an improved pixel for detecting and calculating the number of photons |
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