A sensor circuit, display device and driving method

Abstract

The present disclosure relates to the technical field of display, and discloses a sensor circuit, a display device and a driving method. The sensor circuit comprises: a first threshold compensation sub-circuit coupled with a first sensing transistor, configured to write a reference voltage into a first function node and write a threshold voltage of the first sensing transistor and the reference voltage into a second function node in response to a first initialization signal; a first compensation control sub-circuit coupled with the first sensing transistor, configured to couple the threshold voltage and the reference voltage written into the second function node to a gate of the first sensing transistor in response to a high-level signal; the first sensing transistor is configured to generate a driving current according to the reference voltage and the threshold voltage of the first sensing transistor; and an output control sub-circuit configured to convert the driving current generated by the first sensing transistor into a driving voltage output. Through threshold voltage compensation, the influence of characteristic drift of the sensing transistor is overcome, and the output stability of the sensing transistor is improved.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and provides a sensor circuit, a display device, and a driving method. Background Technology

[0002] Currently, amorphous silicon sensors are often integrated into display panels. However, due to the conductivity characteristics of amorphous silicon, the current output by the amorphous silicon sensor at the same driving voltage will gradually decrease as the operating time increases. This results in a deviation between the electrical signal detected by the amorphous silicon sensor and the actual electrical signal. Summary of the Invention

[0003] This disclosure provides a sensor circuit, a display device, and a driving method to overcome the influence of characteristic drift of a sensing transistor, thereby improving the output stability of the sensing transistor.

[0004] The specific technical solution provided in this disclosure is as follows:

[0005] In a first aspect, embodiments of this disclosure provide a sensor circuit, including: a first sensing transistor, a first threshold compensation sub-circuit, a first compensation control sub-circuit, and an output control sub-circuit;

[0006] The first threshold compensation sub-circuit is coupled to the first sensing transistor and is configured to write a reference voltage into the first functional node and write the threshold voltage and reference voltage of the first sensing transistor into the second functional node in response to the first initialization signal.

[0007] The first compensation control subcircuit is coupled to the first sensing transistor and is configured to provide a reference voltage to the second functional node in response to a high-level signal, and to couple the threshold voltage written to the second functional node and the reference voltage to the gate of the first sensing transistor.

[0008] The first sensing transistor is configured to generate a drive current based on a reference voltage and a threshold voltage of the first sensing transistor.

[0009] The output control subcircuit is coupled to the first sensing transistor and is configured to convert the drive current generated by the first sensing transistor into a drive voltage output.

[0010] Optionally, the first threshold compensation sub-circuit includes a first switching transistor and a second switching transistor;

[0011] The control terminal of the first switching transistor is coupled to the first initialization signal terminal, the first terminal of the first switching transistor is coupled to the first electrode of the first capacitor, and the second terminal of the first switching transistor is coupled to the second terminal of the first sensing transistor.

[0012] The control terminal of the second switching transistor is coupled to the first initialization signal terminal, the first terminal of the second switching transistor is coupled to the reference signal terminal, and the second terminal of the second switching transistor is coupled to the second electrode of the first capacitor.

[0013] Optionally, the first compensation control sub-circuit includes a third switching transistor and a first capacitor;

[0014] The control terminal of the third switching transistor is coupled to the high-level control terminal, the first terminal of the third switching transistor is coupled to the reference signal terminal, and the second terminal of the third switching transistor is coupled to the first electrode of the first capacitor.

[0015] The second terminal of the first capacitor is coupled to the gate of the first sensing transistor.

[0016] Optionally, the output control sub-circuit includes a first resistor;

[0017] The first end of the first resistor is coupled to the power supply signal terminal via the first sensing transistor, and the second end of the first resistor is coupled to the output signal terminal.

[0018] Optionally, the first sensing transistor includes a first sub-sensing transistor and a second sub-sensing transistor, and the threshold voltage of the first sensing transistor is the threshold voltage of the first sub-sensing transistor.

[0019] The gate and source of the first sub-sensing transistor are both coupled to the first threshold compensation sub-circuit, and the drain of the first sub-sensing transistor is coupled to the power supply signal terminal.

[0020] The gate of the second sub-sensing transistor is coupled to the gate of the first sub-sensing transistor, the source of the second sub-sensing transistor is coupled to the output control sub-circuit, and the drain of the second sub-sensing transistor is coupled to the power supply signal terminal.

[0021] Optionally, it further includes at least one second sensing transistor, at least one second threshold compensation sub-circuit, and a selection switch; the at least one second sensing transistor is coupled to the at least one second threshold compensation sub-circuit in a one-to-one correspondence.

[0022] The second threshold compensation sub-circuit is configured to write a reference voltage into the first functional node and write the threshold voltage and reference voltage of the second sensing transistor into the second functional node in response to the second initialization signal.

[0023] The gate of the second sensing transistor is coupled to the gate of the first sensing transistor, and the drain of the second sensing transistor is coupled to the power supply signal terminal.

[0024] The source of the first sensing transistor and the source of the second sensing transistor are both coupled to the output control sub-circuit via a selection switch. The selection switch is configured to turn on the source of the first sensing transistor and the output control sub-circuit in response to a first control signal, or to turn on the source of the second sensing transistor and the output control sub-circuit in response to a second control signal. The second control signal corresponds one-to-one with the second sensing transistor.

[0025] Optionally, the second threshold compensation sub-circuit includes: a fourth switching transistor and a fifth switching transistor;

[0026] The control terminal of the fourth switching transistor is coupled to the second initialization signal terminal, the first terminal of the fourth switching transistor is coupled to the first electrode of the first capacitor, and the second terminal of the fourth switching transistor is coupled to the second terminal of the second sensing transistor.

[0027] The control terminal of the fifth switching transistor is coupled to the second initialization signal terminal, the first terminal of the fifth switching transistor is coupled to the reference signal terminal, and the second terminal of the fifth switching transistor is coupled to the second electrode of the first capacitor.

[0028] Optionally, there are multiple first sensing transistors, multiple first threshold compensation sub-circuits, and multiple first compensation control sub-circuits, and the multiple first sensing transistors, multiple first threshold compensation sub-circuits, and multiple first compensation control sub-circuits correspond one-to-one.

[0029] The sensor circuit also includes: a selection switch;

[0030] The sources of multiple first sensing transistors are coupled to the output control sub-circuit via a selection switch. The selection switch is configured to turn on the source of the corresponding first sensing transistor and the output control sub-circuit in response to a first control signal. The first control signal corresponds one-to-one with the first sensing transistor.

[0031] Secondly, embodiments of this disclosure also provide a display device including the sensor circuit of any of the above.

[0032] Optionally, the display device further includes a display panel and a circuit board connected to the display panel;

[0033] The display panel includes a display area and a non-display area. The first sensing transistor, the first threshold compensation sub-circuit, and the first compensation control sub-circuit are disposed in the non-display area, and the output control sub-circuit is disposed on the circuit board.

[0034] Optionally, the display area includes a display transistor, the active layer of which is made of low-temperature polycrystalline silicon or metal oxide, and the active layer of the first sensing transistor is made of amorphous silicon.

[0035] Optionally, the display transistor is electrically connected to the gate line and data line of the display area, the gate of the first sensing transistor is fabricated in the same layer and with the same material as the gate of the display transistor, the source of the first sensing transistor is fabricated in the same layer and with the same material as the source of the display transistor, and the drain of the first sensing transistor is fabricated in the same layer and with the same material as the drain of the display transistor.

[0036] Thirdly, embodiments of this disclosure also provide a method for driving a sensor circuit, including:

[0037] In response to a first initialization signal, the first threshold compensation sub-circuit writes a reference voltage into a first functional node and writes the threshold voltage and reference voltage of the first sensing transistor into a second functional node.

[0038] In response to a high-level signal, the first compensation control sub-circuit provides a reference voltage to the second functional node and couples the threshold voltage written to the second functional node and the reference voltage to the gate of the first sensing transistor.

[0039] The first sensing transistor generates a drive current based on the reference voltage and the threshold voltage of the first sensing transistor.

[0040] The output control sub-circuit converts the drive current generated by the first sensing transistor into a drive voltage output.

[0041] The beneficial effects of this disclosure are as follows:

[0042] In summary, this disclosure provides a sensor circuit, a display device, and a driving method. The sensor circuit includes a first sensing transistor, a first threshold compensation sub-circuit, a first compensation control sub-circuit, and an output control sub-circuit. The first threshold compensation sub-circuit is coupled to the first sensing transistor and configured to write a reference voltage to a first functional node in response to a first initialization signal, and to write the threshold voltage and reference voltage of the first sensing transistor to a second functional node. The first compensation control sub-circuit is coupled to the first sensing transistor and configured to provide the reference voltage to the second functional node in response to a high-level signal, and to write the voltage to the second functional node. The threshold voltage and reference voltage of the node are coupled to the gate of the first sensing transistor. The first sensing transistor is configured to generate a drive current based on the reference voltage and the threshold voltage of the first sensing transistor. The output control sub-circuit is coupled to the first sensing transistor and configured to convert the drive current generated by the first sensing transistor into a drive voltage output. In the above scheme, the threshold voltage of the sensing transistor is detected before the sensing transistor performs light or temperature detection sampling, thereby realizing the compensation of the threshold voltage of the sensing transistor, overcoming the influence of the drift of the output characteristics of the sensing transistor caused by the increase of working time, and improving the output stability of the sensing transistor.

[0043] Other features and advantages of this disclosure will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the disclosure. The objects and other advantages of this disclosure may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0044] The accompanying drawings, which are included to provide a further understanding of this disclosure and form part of this disclosure, illustrate exemplary embodiments of the present disclosure and are used to explain the disclosure, but do not constitute an undue limitation of the disclosure. In the drawings:

[0045] Figure 1 This is a schematic diagram of the composition of a sensor circuit according to an embodiment of this disclosure;

[0046] Figure 2 This is a circuit diagram of the first type of sensor circuit in the embodiments of this disclosure;

[0047] Figure 3 This is a first timing diagram of the first type of sensor circuit in the embodiments of this disclosure;

[0048] Figure 4 This is a circuit diagram of the second type of sensor circuit in an embodiment of this disclosure;

[0049] Figure 5 This is a second timing diagram of the second type of sensor circuit in the embodiments of this disclosure;

[0050] Figure 6 This is a schematic diagram of another sensor circuit in an embodiment of this disclosure;

[0051] Figure 7 This is a circuit diagram of the third type of sensor circuit in the embodiments of this disclosure;

[0052] Figure 8 This is a third timing diagram of the third type of sensor circuit in the embodiments of this disclosure;

[0053] Figure 9 This is a schematic diagram of a display device according to an embodiment of the present disclosure;

[0054] Figure 10 This is a flowchart of the driving method for the sensor circuit in an embodiment of this disclosure. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the technical solutions of this disclosure, and not all embodiments. Based on the embodiments recorded in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the technical solutions of this disclosure.

[0056] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0057] The preferred embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0058] See Figure 1 As shown in the embodiments of this application, a sensor circuit includes: a first sensing transistor DT, a first threshold compensation sub-circuit 10, a first compensation control sub-circuit 20, and an output control sub-circuit 30.

[0059] See Figure 2 As shown, the first threshold compensation sub-circuit 10 is coupled to the first sensing transistor DT and is configured to write the reference voltage Vref into the first functional node A and write the threshold voltage Vth and the reference voltage Vref of the first sensing transistor DT into the second functional node B in response to the first initialization signal Vinit1.

[0060] See Figure 2 As shown, the first threshold compensation sub-circuit 10 includes a first switching transistor M1 and a second switching transistor M2.

[0061] The first switching transistor M1 and Figure 2 The connection relationships between other components are as follows: the control terminal of the first switching transistor M1 is coupled to the first initialization signal Vinit1 terminal, the first terminal of the first switching transistor M1 is coupled to the first electrode of the first capacitor C1, and the second terminal of the first switching transistor M1 is coupled to the second terminal of the first sensing transistor DT.

[0062] During implementation, when the first initialization signal Vinit1 is high, the first switching transistor M1 is turned on, the first terminal of the first capacitor C1, which is the second functional node B, is connected to the first terminal of the first switching transistor M1, and the second terminal of the first switching transistor M1 is connected to the second terminal of the first sensing transistor DT.

[0063] The second switching transistor M2 and Figure 2 The connection relationships between other components are as follows: the control terminal of the second switching transistor M2 is coupled to the first initialization signal Vinit1 terminal, the first terminal of the second switching transistor M2 is coupled to the reference signal terminal, and the second terminal of the second switching transistor M2 is coupled to the second electrode of the first capacitor C1.

[0064] During implementation, when the first initialization signal Vinit1 is high, the second switching transistor M2 is turned on, the reference signal terminal is connected to the first terminal of the second switching transistor M2, and the second terminal of the first capacitor C1, which is the first functional node A, is connected to the second terminal of the second switching transistor M2.

[0065] When the first initialization signal Vinit1 is high, both the first switching transistor M1 and the second switching transistor M2 are turned on. The reference voltage Vref at the reference signal terminal is written to the first functional node A through the turned-on second switching transistor M2. The reference voltage Vref at the first functional node A turns on the first sensing transistor DT. The power signal VDD at the power signal terminal VDD is written to the second functional node B through the turned-on first sensing transistor DT. In this case, the voltage across the first capacitor C1 is unbalanced, and the charging process begins. After the first capacitor C1 is fully charged, the voltage of the first functional node A is the reference voltage Vref, and the voltage of the second functional node B is the power signal VDD-Vth. The aforementioned Vth is the threshold voltage Vth of the first sensing transistor DT. Since the reference voltage Vref is equal to the power supply signal VDD, the voltage difference across the first capacitor C1 is Vth, which enables the detection of the threshold voltage Vth of the first sensing transistor DT and stores the threshold voltage Vth on the first capacitor C1. Then, the threshold voltage Vth and the reference voltage Vref of the first sensing transistor DT are written into the second functional node B, which is the gate of the first sensing transistor DT.

[0066] After the first threshold compensation sub-circuit 10 obtains the threshold voltage Vth of the first sensing transistor DT, the first compensation control sub-circuit 20 is coupled to the first sensing transistor DT and configured to provide the reference voltage Vref to the second functional node B in response to the high-level signal VGH, and to couple the threshold voltage Vth and the reference voltage Vref written to the second functional node B to the gate of the first sensing transistor DT.

[0067] See Figure 2 As shown, the first compensation control sub-circuit 20 includes a third switching transistor M3 and a first capacitor C1.

[0068] The third switching transistor M3 and Figure 2The connection relationships between other components are as follows: the control terminal of the third switching transistor M3 is coupled to the high-level control terminal, the first terminal of the third switching transistor M3 is coupled to the reference signal terminal, and the second terminal of the third switching transistor M3 is coupled to the first electrode of the first capacitor C1.

[0069] The second terminal of the first capacitor C1 is coupled to the gate of the first sensing transistor DT.

[0070] During implementation, the high-level signal VGH in the high-level control terminal turns on the third switching transistor M3. The reference voltage Vref in the reference signal terminal is provided to the second functional node B through the turned-on third switching transistor M3. Furthermore, it is provided to the gate of the first sensing transistor DT through the first capacitor C1. Since the first capacitor C1 stores the threshold voltage Vth, the threshold voltage Vth and the reference voltage Vref are coupled to the gate of the first sensing transistor DT.

[0071] In the specific implementation process, when the first initialization signal Vinit1 is low, both the first switching transistor M1 and the second switching transistor M2 are turned off, the first functional node A is in a floating state, the high-level signal VGH turns on the third switching transistor M3, and the voltage of the second functional node B rises from VDD-Vth to Vref (the same as VDD). Under the action of the first capacitor C1, the voltage of the first functional node A rises synchronously to Vref+Vth.

[0072] The first sensing transistor DT is configured to generate a drive current based on the reference voltage Vref and the threshold voltage Vth of the first sensing transistor DT.

[0073] The aforementioned output control sub-circuit 30 is coupled to the first sensing transistor DT and is configured to convert the drive current generated by the first sensing transistor DT into a drive voltage output.

[0074] Specifically, the output control sub-circuit 30 includes a first resistor R1.

[0075] The first resistor R1 and R1 Figure 2 The connection relationship between other components is as follows: the first end of the first resistor R1 is coupled to the power signal terminal VDD through the first sensing transistor DT, and the second end of the first resistor R1 is coupled to the output signal terminal.

[0076] In summary, by setting the first resistor R1, the driving current generated by the first sensing transistor DT can be converted into a driving voltage output.

[0077] During implementation, when the threshold voltage Vth and the reference voltage Vref are coupled to the gate of the first sensing transistor DT, the first sensing transistor DT generates a drive current based on the threshold voltage Vth and the reference voltage Vref. The calculation formula for the drive current is as follows (1).

[0078]

[0079] Since μ, Vref, VDD, and R are all constant values, the driving current I is also a constant value. Therefore, the output voltage Vout = I * R is also a constant value. That is, for different threshold voltages Vth, the output voltage Vout is also a fixed value, thus overcoming the influence of the change in threshold voltage Vth caused by the increase of working time on the output result.

[0080] The following section, with reference to timing diagrams, details the operation of the first type of sensor circuit described above. Figure 3 As shown.

[0081] Timing T1 stage: reference voltage Vref = 1, first initialization signal Vinit1 = 1, power supply signal VDD = 0, high-level signal VGH = 0, output signal Vout = 0.

[0082] See Figure 3 As shown, when the first initialization signal Vinit1 is high, the first switching transistor M1 and the second switching transistor M2 are turned on. The high voltage of the reference voltage Vref is written to the first functional node A, which in turn turns on the first sensing transistor DT. The low voltage of the power supply signal VDD causes the second functional node B to complete initialization. When the high-level signal VGH is low, the third switching transistor M3 is turned off. In this case, the output signal terminal Vout of the first sensing transistor DT does not output a signal.

[0083] Timing T2 stage: reference voltage Vref = 1, first initialization signal Vinit1 = 1, power supply signal VDD = 1, high level signal VGH = 0, output signal Vout = 0.

[0084] See Figure 3As shown, when the first initialization signal Vinit1 is high, the first switching transistor M1 and the second switching transistor M2 are turned on. The high voltage of the reference voltage Vref is written to the first functional node A, which in turn turns on the first sensing transistor DT. The high voltage of the power supply signal VDD causes the first capacitor C1 to start the charging process. The charging process stops when the potential of the second functional node B stabilizes at the difference between the power supply signal VDD and the threshold voltage Vth. Since the high voltage of the reference voltage Vref is equal to the high voltage of the power supply signal VDD, the voltage stored in the first capacitor C1 after the charging process is completed is the threshold voltage Vth. When the high-level signal VGH is low, the third switching transistor M3 is turned off. In this case, the output signal terminal Vout of the first sensing transistor DT does not output a signal.

[0085] Timing T3 stage: reference voltage Vref = 1, first initialization signal Vinit1 = 0, power supply signal VDD = 1, high level signal VGH = 1, output signal Vout = 1.

[0086] See Figure 3 As shown, when the first initialization signal Vinit1 is low voltage, the first switching transistor M1 and the second switching transistor M2 are both off, the high-level signal VGH is high voltage, and the third switching transistor M3 is on. In this case, the output signal terminal Vout of the first sensing transistor DT outputs the driving current. As can be seen from the above formula (1), the above driving current I = μ*(Vref-Vout)*(VDD-Vout), that is, the driving current is no longer affected by the threshold voltage Vth of the first sensing transistor DT.

[0087] In addition, it should be noted that, in order to eliminate the influence of rising and falling edges in the timing process, timing parameters t1, t2, t3 and t4 are set for buffering rising and falling edges in this embodiment of the application. The above-mentioned t1, t2, t3 and t4 are greater than or equal to 0, and the above-mentioned T1, T2 and T3 are greater than 0.

[0088] Considering that the above scheme requires obtaining the threshold voltage Vth of the first sensing transistor DT first, and then generating a drive current based on the first sensing transistor DT, in order to distinguish the acquisition of the threshold voltage Vth from the generation of the drive current, this application also proposes a second sensor circuit, that is, using different sensing transistors to complete the acquisition of the threshold voltage Vth and the generation of the drive current respectively.

[0089] See Figure 4 As shown, the first sensing transistor DT includes a first sub-sensing transistor DT1 and a second sub-sensing transistor DT2, and the threshold voltage Vth of the first sensing transistor DT is the same as the threshold voltage Vth of the first sub-sensing transistor DT1.

[0090] It should be noted that the first sub-sensing transistor DT1, the second sub-sensing transistor DT2, and the first sensing transistor DT are all of the same type and model, that is, the threshold voltage Vth of the first sub-sensing transistor DT1, the threshold voltage Vth of the second sub-sensing transistor DT2, and the threshold voltage Vth of the first sensing transistor DT are all equal.

[0091] The first sub-sensing transistor DT1 and Figure 4 The connection relationship between other components is as follows: the gate and source of the first sub-sensing transistor DT1 are both coupled to the first threshold compensation sub-circuit 10, and the drain of the first sub-sensing transistor DT1 is coupled to the power supply signal terminal VDD.

[0092] The second sub-sensing transistor DT2 and Figure 4 The connection relationships between other components are as follows: the gate of the second sub-sensing transistor DT2 is coupled to the gate of the first sub-sensing transistor DT1, the source of the second sub-sensing transistor DT2 is coupled to the output control sub-circuit 30, and the drain of the second sub-sensing transistor DT2 is coupled to the power supply signal terminal VDD.

[0093] As can be seen from the above connection relationship, in order to distinguish between the acquisition of the threshold voltage Vth and the generation of the driving current, the gate and source of the first sub-sensing transistor DT1 are both coupled to the first threshold compensation sub-circuit 10, while the second sub-sensing transistor DT2 is not coupled to the first threshold compensation sub-circuit 10; the source of the second sub-sensing transistor DT2 is coupled to the output control sub-circuit 30, and the source of the first sub-sensing transistor DT1 is no longer coupled to the output control sub-circuit 30.

[0094] Furthermore, in order to ensure that the threshold voltage Vth obtained by the first sub-sensing transistor DT1 can be smoothly transmitted to the second sub-sensing transistor DT2, the gate of the second sub-sensing transistor DT2 is coupled to the gate of the first sub-sensing transistor DT1.

[0095] During implementation, after obtaining the threshold voltage Vth of the first sub-sensing transistor DT1, the first threshold compensation sub-circuit 10 and the first compensation control sub-circuit 20 couple the threshold voltage Vth and the reference voltage Vref to the gate of the first sensing transistor DT. Then, through the gate of the first sensing transistor DT, the threshold voltage Vth and the reference voltage Vref are coupled to the gate of the second sensing transistor TDA. The second sensing transistor TDA outputs a drive current based on this. The working process here is similar to the working process of the first type of sensor circuit mentioned above, and will not be described again.

[0096] The following section, with reference to timing diagrams, details the operation of the second type of sensor circuit described above. Figure 5 As shown.

[0097] Timing T1 stage: reference voltage Vref = 1, first initialization signal Vinit1 = 1, power supply signal VDD = 0, high-level signal VGH = 0, output signal Vout = 0.

[0098] See Figure 5 As shown, when the first initialization signal Vinit1 is high, the first switching transistor M1 and the second switching transistor M2 are turned on. The high voltage of the reference voltage Vref is written to the first functional node A, thereby turning on the first sub-sensor transistor DT1. The low voltage of the power supply signal VDD causes the second functional node B to complete initialization. When the high-level signal VGH is low, the third switching transistor M3 is turned off. In this case, the output signal terminal Vout of the first sub-sensor transistor DT1 does not output a signal.

[0099] Timing T2 stage: reference voltage Vref = 1, first initialization signal Vinit1 = 1, power supply signal VDD = 1, high level signal VGH = 0, output signal Vout = 0.

[0100] See Figure 5 As shown, when the first initialization signal Vinit1 is high, the first switching transistor M1 and the second switching transistor M2 are turned on. The high voltage of the reference voltage Vref is written into the first functional node A, which in turn turns on the first sub-sensing transistor DT1. The high voltage of the power supply signal VDD causes the first capacitor C1 to start the charging process. The charging process stops when the potential of the second functional node B stabilizes to the difference between the power supply signal VDD and the threshold voltage Vth. Since the high voltage of the reference voltage Vref is equal to the high voltage of the power supply signal VDD, the voltage stored in the first capacitor C1 after the charging process is completed is the threshold voltage Vth. When the high-level signal VGH is low, the third switching transistor M3 is turned off. In this case, the output signal terminal Vout of the first sub-sensing transistor DT1 does not output a signal. It should be noted that Vout is high in the timing stage T2 because the high voltage of the power supply signal VDD is generated after the second sub-sensing transistor DT2 is turned on. The output signal is not the driving current generated by the second sub-sensing transistor DT2.

[0101] Timing T3 stage: Reference voltage Vref = 1, first initialization signal Vinit1 = 0, power supply signal VDD = 0, high level signal VGH = 1, output signal Vout = 0.

[0102] See Figure 5As shown, when the first initialization signal Vinit1 is low, both the first switching transistor M1 and the second switching transistor M2 are turned off, the high-level signal VGH is high, and the third switching transistor M3 is turned on. In this case, the threshold voltage Vth and the reference voltage Vref are further coupled to the gate of the second sub-sensing transistor DT2.

[0103] Timing T4 stage: Reference voltage Vref = 1, first initialization signal Vinit1 = 0, power supply signal VDD = 1, high level signal VGH = 0, output signal Vout = 1.

[0104] See Figure 5 As shown, when the first initialization signal Vinit1 is low voltage, both the first switching transistor M1 and the second switching transistor M2 are turned off. When the high-level signal VGH is low voltage, the third switching transistor M3 is turned off. In this case, the output signal terminal Vout of the second sub-sensing transistor DT2 connected to the output control sub-circuit 30 outputs the driving current. As can be seen from the above formula (1), the above driving current I = μ*(Vref-Vout)*(VDD-Vout), that is, the driving current is no longer affected by the threshold voltage Vth of the second sub-sensing transistor DT2.

[0105] In addition, it should be noted that, in order to eliminate the influence of rising and falling edges in the timing process, the embodiments of this application also set timing t1, t2, t3, t4 and t5 for buffering rising and falling edges, wherein t1, t2, t3, t4 and t5 are greater than or equal to 0, and T1, T2, T3 and T4 are greater than 0.

[0106] Considering that the number of sensing transistors is usually at least one, in order to make it easier to obtain the driving current, a third sensor circuit is proposed in this application embodiment. Compared with the first sensor circuit, the third sensor circuit realizes the output of multiple driving currents through multiple sensing transistors and corresponding threshold compensation sub-circuits.

[0107] See Figure 6 As shown, the third type of sensor circuit further includes at least one second sensing transistor TDA, at least one second threshold compensation sub-circuit 40, and a selection switch. The at least one second sensing transistor TDA is coupled to the at least one second threshold compensation sub-circuit 40 in a one-to-one correspondence.

[0108] It should be noted that in the third type of sensor circuit described above, the second sensing transistor TDA and the second threshold compensation sub-circuit 40 are in one-to-one correspondence, meaning one second sensing transistor TDA corresponds to one second threshold compensation sub-circuit 40. The first compensation control sub-circuit 20 and the output control sub-circuit 30 are shared; that is, the first sensing transistor DT and at least one second sensing transistor TDA share the aforementioned first compensation control sub-circuit 20 and output control sub-circuit 30. To ensure that the output drive currents are not affected, the first sensing transistor DT and at least one second sensing transistor TDA are connected to the output control sub-circuit 30 in a time-sharing manner via a selection switch.

[0109] During implementation, the second threshold compensation sub-circuit 40 is configured to write the reference voltage Vref into the first functional node A in response to the second initialization signal Vinit2, and to write the threshold voltage Vth and the reference voltage Vref of the second sensing transistor TDA into the second functional node B.

[0110] Similar to the function of the first threshold compensation sub-circuit 10, during implementation, when the second initialization signal Vinit2 is high voltage, the second threshold compensation sub-circuit 40 writes the reference voltage Vref into the first functional node A, and writes the threshold voltage Vth of the second sensing transistor TDA and the reference voltage Vref into the second functional node B, and charges the first capacitor C1 to obtain the threshold voltage Vth of the second sensing transistor TDA.

[0111] See Figure 7 As shown, the gate of the second sensing transistor TDA is coupled to the gate of the first sensing transistor DT, and the drain of the second sensing transistor TDA is coupled to the power supply signal terminal VDD.

[0112] The source of the first sensing transistor DT and the source of the second sensing transistor TDA are both coupled to the output control sub-circuit 30 via a selection switch. The selection switch is configured to turn on the source of the first sensing transistor DT and the output control sub-circuit 30 in response to a first control signal, or to turn on the source of the second sensing transistor TDA and the output control sub-circuit 30 in response to a second control signal. The second control signal corresponds one-to-one with the second sensing transistor TDA.

[0113] In the third type of sensor circuit, both the first sensing transistor DT and the second sensing transistor TDA can generate a drive current after acquiring the corresponding threshold voltage Vth. However, since there is only one corresponding output control sub-circuit 30, a selection switch is provided in this embodiment. During implementation, the selection switch is configured to connect the source of the first sensing transistor DT to the output control sub-circuit 30 in response to the first control signal, or to connect the source of the second sensing transistor TDA to the output control sub-circuit 30 in response to the second control signal.

[0114] It should be noted that the first and second control signals mentioned above are generated in a time-division manner. That is, the drive current of the first sensing transistor DT and the drive current of the second sensing transistor TDA are output in a time-division manner through the setting of the selection switch. Furthermore, when there are multiple second sensing transistors TDA, there are also multiple second control signals, and each second control signal is also generated in a time-division manner.

[0115] The second threshold compensation sub-circuit 40 is described in detail below. The second threshold compensation sub-circuit 40 includes: a fourth switching transistor M1A and a fifth switching transistor M2A.

[0116] The fourth switching transistor M1A and Figure 7 The connection relationships between other components are as follows: the control terminal of the fourth switching transistor M1A is coupled to the second initialization signal Vinit2 terminal; the first terminal of the fourth switching transistor M1A is coupled to the first electrode of the first capacitor C1; and the second terminal of the fourth switching transistor M1A is coupled to the second terminal of the second sensing transistor TDA.

[0117] The fifth switching transistor M2A and Figure 7 The connection relationships between other components are as follows: the control terminal of the fifth switching transistor M2A is coupled to the second initialization signal Vinit2 terminal, the first terminal of the fifth switching transistor M2A is coupled to the reference signal terminal, and the second terminal of the fifth switching transistor M2A is coupled to the second electrode of the first capacitor C1.

[0118] During implementation, when the second initialization signal Vinit2 is high, the fourth switching transistor M1A and the fifth switching transistor M2A are turned on. The reference voltage Vref of the reference signal terminal (usually the second reference signal terminal Vinit2) is written to the first functional node A through the turned-on fifth switching transistor M2A. The reference voltage Vref of the first functional node A turns on the second sensing transistor TDA. The power signal VDD of the power signal terminal VDD is written to the second functional node B through the turned-on second sensing transistor TDA. In this case, the voltage across the first capacitor C1 is unbalanced, and the charging process begins. After the first capacitor C1 is fully charged, the voltage of the first functional node A is the reference voltage Vref, and the voltage of the second functional node B is the power signal VDD-Vth. The aforementioned Vth is the threshold voltage Vth of the second sensing transistor TDA. Since the reference voltage Vref is equal to the power supply signal VDD, the voltage difference across the first capacitor C1 is Vth, which enables the detection of the threshold voltage Vth of the second sensing transistor TDA and stores the threshold voltage Vth on the first capacitor C1. Then, the threshold voltage Vth and the reference voltage Vref of the second sensing transistor TDA are written into the second functional node B, which is the gate of the second sensing transistor TDA.

[0119] It should be noted that in the third type of sensor circuit, the first compensation control sub-circuit 20 is shared by the first sensing transistor DT and the second sensing transistor TDA. The second sensing transistor TDA has the same polarity and model as the first sensing transistor DT. There can be multiple second sensing transistors TDA. Furthermore, the second sensing transistor TDA can be replaced by two sub-sensing transistors. The functions of the two sub-sensing transistors are similar to those of the first sub-sensing transistor DT1 and the second sub-sensing transistor DT2, which will not be described in detail here.

[0120] In another embodiment of the sensor circuit, the first compensation control sub-circuit 20 can also be configured as multiple, that is, multiple first sensing transistors DT, multiple first threshold compensation sub-circuits 10, and multiple first compensation control sub-circuits 20, and the multiple first sensing transistors DT, multiple first threshold compensation sub-circuits 10, and multiple first compensation control sub-circuits 20 correspond one-to-one.

[0121] In order to enable the various sensing transistors to output drive current in an orderly manner, the above sensor circuit also includes a selection switch.

[0122] During implementation, the sources of multiple first sensing transistors DT are coupled to the output control sub-circuit 30 through a selection switch. The selection switch is configured to turn on the source of the corresponding first sensing transistor DT and the output control sub-circuit 30 in response to the first control signal. The first control signal corresponds one-to-one with the first sensing transistor DT.

[0123] It should be noted that the number of the first control signals is the same as the number of the first sensing transistors DT, but there are differences between the various first control signals. When a certain first control signal is valid, the first sensing transistor DT corresponding to that first control signal is connected to the selection switch.

[0124] When there are multiple first compensation control sub-circuits 20, the operating timing of each first sensing transistor DT is the same as that of the second type of sensor circuit. (See reference...) Figure 8 As shown, each of the first sensing transistors DT is arranged according to... Figure 5 The order of operations shown is as follows, and will not be elaborated further here.

[0125] Based on the same inventive concept, see [reference] Figure 9 As shown, this disclosure provides a display device including the sensor circuit described above.

[0126] In this embodiment of the invention, the display device can be any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigator. Other essential components of the display device are understood by those skilled in the art and will not be described in detail here, nor should they be construed as limiting the invention.

[0127] For example, the display device also includes a display panel and a circuit board connected to the display panel.

[0128] The display panel includes a display area and a non-display area. The first sensing transistor, the first threshold compensation sub-circuit, and the first compensation control sub-circuit are disposed in the non-display area, and the output control sub-circuit is disposed on the circuit board.

[0129] In this embodiment, the display panel is coupled to the circuit board via connectors such as Chip On Flex (or Chip On Film, COF). The control chip on the circuit board controls the first sensing transistor to turn on and off, and introduces the driving current generated by the first sensing transistor into a resistor located on the circuit board for output.

[0130] For example, the display area includes a display transistor, the active layer of the display transistor is made of low-temperature polycrystalline silicon or metal oxide material, and the active layer of the first sensing transistor is made of amorphous silicon.

[0131] For example, the display transistor is electrically connected to the gate line and data line of the display area, the gate of the first sensing transistor is fabricated in the same layer and with the same material as the gate of the display transistor, the source of the first sensing transistor is fabricated in the same layer and with the same material as the source of the display transistor, and the drain of the first sensing transistor is fabricated in the same layer and with the same material as the drain of the display transistor.

[0132] Based on the same inventive concept, this disclosure provides a method for driving a sensor circuit, see below. Figure 10 As shown, it includes:

[0133] Step 201: In response to the first initialization signal, the first threshold compensation sub-circuit writes the reference voltage into the first functional node and writes the threshold voltage and reference voltage of the first sensing transistor into the second functional node.

[0134] During implementation, under the action of the first initialization signal, the first threshold compensation sub-circuit charges the first capacitor through the first functional node and the second functional node, thereby using the first capacitor to obtain the threshold voltage of the first sensing transistor.

[0135] Step 202: In response to a high-level signal, the first compensation control sub-circuit provides a reference voltage to the second functional node and couples the threshold voltage written to the second functional node and the reference voltage to the gate of the first sensing transistor.

[0136] During implementation, the first compensation control sub-circuit couples the threshold voltage and reference voltage to the gate of the first sensing transistor under the action of a high-level signal, preparing for the first sensing transistor to generate a drive current.

[0137] Step 203: The first sensing transistor generates a drive current based on the reference voltage and the threshold voltage of the first sensing transistor.

[0138] During implementation, when the power supply voltage is high, the first sensing transistor generates a drive current based on the reference voltage and the threshold voltage of the first sensing transistor. This drive current is independent of the threshold voltage of the first sensing transistor.

[0139] Step 204: The output control sub-circuit converts the drive current generated by the first sensing transistor into a drive voltage output.

[0140] During implementation, after the driving current generated by the first sensing transistor, the output control sub-circuit converts the driving current into a driving voltage output.

[0141] In summary, the present disclosure provides a sensor circuit, display device, and driving method. The sensor circuit includes a first sensing transistor, a first threshold compensation sub-circuit, a first compensation control sub-circuit, and an output control sub-circuit. The first threshold compensation sub-circuit is coupled to the first sensing transistor and configured to write a reference voltage to a first functional node in response to a first initialization signal, and to write the threshold voltage and reference voltage of the first sensing transistor to a second functional node. The first compensation control sub-circuit is coupled to the first sensing transistor and configured to provide the reference voltage to the second functional node in response to a high-level signal, and to write the voltage to the second functional node. The threshold voltage and reference voltage of the node are coupled to the gate of the first sensing transistor. The first sensing transistor is configured to generate a drive current based on the reference voltage and the threshold voltage of the first sensing transistor. The output control sub-circuit is coupled to the first sensing transistor and configured to convert the drive current generated by the first sensing transistor into a drive voltage output. In the above scheme, the threshold voltage of the sensing transistor is detected before the sensing transistor performs light or temperature detection sampling, thereby realizing the compensation of the threshold voltage of the sensing transistor, overcoming the influence of the drift of the output characteristics of the sensing transistor caused by the increase of working time, and improving the output stability of the sensing transistor.

[0142] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program product systems. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product system implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0143] This disclosure is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program product systems according to this disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0144] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0145] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0146] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A sensor circuit, characterized in that, include: The first sensing transistor, the first threshold compensation sub-circuit, the first compensation control sub-circuit, and the output control sub-circuit; The first threshold compensation sub-circuit is coupled to the first sensing transistor and configured to, in response to a first initialization signal, write a reference voltage to the second terminal of a first capacitor and write the threshold voltage and reference voltage of the first sensing transistor to the first terminal of the first capacitor. The first threshold compensation sub-circuit includes a first switching transistor and a second switching transistor. The control terminal of the first switching transistor is coupled to the first initialization signal terminal. The first terminal of the first switching transistor is coupled to the first terminal of the first capacitor. The second terminal of the first switching transistor is coupled to the second terminal of the first sensing transistor. The control terminal of the second switching transistor is coupled to the first initialization signal terminal. The first terminal of the second switching transistor is coupled to the reference signal terminal. The second terminal of the second switching transistor is coupled to the second terminal of the first capacitor. The first compensation control sub-circuit is coupled to the first sensing transistor and configured to, in response to a high-level signal, provide the reference voltage to the first terminal of the first capacitor and couple the threshold voltage written to the first terminal of the first capacitor and the reference voltage to the gate of the first sensing transistor. The first compensation control sub-circuit includes a third switching transistor and a first capacitor. The control terminal of the third switching transistor is coupled to a high-level control terminal, the first terminal of the third switching transistor is coupled to a reference signal terminal, the second terminal of the third switching transistor is coupled to the first terminal of the first capacitor, and the second terminal of the first capacitor is coupled to the gate of the first sensing transistor. The first sensing transistor is configured to generate a drive current based on a reference voltage and a threshold voltage of the first sensing transistor. The output control subcircuit is coupled to the first sensing transistor and is configured to convert the drive current generated by the first sensing transistor into a drive voltage output.

2. The circuit as described in claim 1, characterized in that, The output control sub-circuit includes a first resistor; The first end of the first resistor is coupled to the output signal terminal, and the second end of the first resistor is coupled to the ground terminal.

3. The circuit as described in claim 1, characterized in that, The first sensing transistor includes a first sub-sensing transistor and a second sub-sensing transistor, and the threshold voltage of the first sensing transistor is the threshold voltage of the first sub-sensing transistor. The gate and source of the first sub-sensing transistor are both coupled to the first threshold compensation sub-circuit, and the drain of the first sub-sensing transistor is coupled to the power supply signal terminal. The gate of the second sub-sensing transistor is coupled to the gate of the first sub-sensing transistor, the source of the second sub-sensing transistor is coupled to the output control sub-circuit, and the drain of the second sub-sensing transistor is coupled to the power supply signal terminal.

4. The circuit as described in claim 3, characterized in that, It also includes at least one second sensing transistor, at least one second threshold compensation sub-circuit, and a selection switch; the at least one second sensing transistor is coupled to the at least one second threshold compensation sub-circuit in a one-to-one correspondence; The second threshold compensation sub-circuit is configured to, in response to a second initialization signal, write a reference voltage to the second terminal of the first capacitor and write the threshold voltage and reference voltage of the second sensing transistor to the first terminal of the first capacitor. The gate of the second sensing transistor is coupled to the gate of the first sensing transistor, and the drain of the second sensing transistor is coupled to the power signal terminal. The source of the first sensing transistor and the source of the second sensing transistor are both coupled to the output control sub-circuit via the selection switch. The selection switch is configured to turn on the source of the first sensing transistor and the output control sub-circuit in response to a first control signal, or to turn on the source of the second sensing transistor and the output control sub-circuit in response to a second control signal. The second control signal corresponds one-to-one with the second sensing transistor.

5. The circuit as described in claim 4, characterized in that, The second threshold compensation sub-circuit includes: a fourth switching transistor and a fifth switching transistor; The control terminal of the fourth switching transistor is coupled to the second initialization signal terminal, the first terminal of the fourth switching transistor is coupled to the first electrode of the first capacitor, and the second terminal of the fourth switching transistor is coupled to the second terminal of the second sensing transistor. The control terminal of the fifth switching transistor is coupled to the second initialization signal terminal, the first terminal of the fifth switching transistor is coupled to the reference signal terminal, and the second terminal of the fifth switching transistor is coupled to the second electrode of the first capacitor.

6. The circuit as described in claim 1 or 2, characterized in that, There are multiple first sensing transistors, multiple first threshold compensation sub-circuits, and multiple first compensation control sub-circuits, and the multiple first sensing transistors, the multiple first threshold compensation sub-circuits, and the multiple first compensation control sub-circuits correspond one-to-one; The sensor circuit also includes: a selection switch; The sources of the plurality of first sensing transistors are coupled to the output control sub-circuit via the selection switch. The selection switch is configured to turn on the source of the corresponding first sensing transistor to the output control sub-circuit in response to a first control signal. The first control signal corresponds one-to-one with the first sensing transistor.

7. A display device, characterized in that, Includes the sensor circuit as described in any one of claims 1-6.

8. The display device as claimed in claim 7, characterized in that, The display device further includes a display panel and a circuit board connected to the display panel; The display panel includes a display area and a non-display area. A first sensing transistor, a first threshold compensation sub-circuit, and a first compensation control sub-circuit are disposed in the non-display area, and an output control sub-circuit is disposed on the circuit board.

9. The display device as claimed in claim 8, characterized in that, The display area includes a display transistor, the active layer of which is made of low-temperature polycrystalline silicon or metal oxide material, and the active layer of the first sensing transistor is made of amorphous silicon.

10. The display device as claimed in claim 9, characterized in that, The display transistor is electrically connected to the gate line and data line of the display area. The gate of the first sensing transistor is made of the same layer and material as the gate of the display transistor. The source of the first sensing transistor is made of the same layer and material as the source of the display transistor. The drain of the first sensing transistor is made of the same layer and material as the drain of the display transistor.

11. A driving method for a sensor circuit as described in any one of claims 1-6, characterized in that, include: In response to a first initialization signal, the first threshold compensation sub-circuit writes a reference voltage to the second terminal of the first capacitor and writes the threshold voltage and reference voltage of the first sensing transistor to the first terminal of the first capacitor. In response to a high-level signal, the first compensation control sub-circuit provides the reference voltage to the first terminal of the first capacitor and couples the threshold voltage written to the first terminal of the first capacitor and the reference voltage to the gate of the first sensing transistor. The first sensing transistor generates a drive current based on the reference voltage and the threshold voltage of the first sensing transistor. The output control sub-circuit converts the drive current generated by the first sensing transistor into a drive voltage output.

Images