PIXEL CIRCUIT AND DRIVING METHOD THEREFOR, AND DISPLAY DEVICE

A pixel circuit, a driving method therefor and a display device. The pixel circuit includes a voltage control circuit, a current control circuit and a light-emitting circuit. The voltage control circuit includes a first driving circuit, a coupling circuit and a first voltage write circuit. The coupling circuit is configured to couple a reset signal to a control terminal of the first driving circuit to reset a voltage of a control terminal of the current control circuit; or the voltage control circuit further includes a reset circuit, where the reset circuit is connected between a first power line and a control terminal of the current control circuit and configured to reset a voltage of the control terminal of the current control circuit.

TECHNICAL FIELD

The present application relates to the field of display technology, for example, a pixel circuit, a driving method therefor and a display device.

BACKGROUND

With the ongoing development of display technology, increasingly high requirements are imposed on the display effects of display devices.

A display device generally includes a pixel circuit and a light-emitting element. The pixel circuit generally controls, in an analog pulse-width modulation (PWM) mode, the light-emitting element to emit light. However, in the related art, the pixel circuit involves many types of signals and has a complex circuit structure, making it impossible to achieve high pixels per inch (PPI).

SUMMARY

The present application provides a pixel circuit, a driving method therefor and a display device to simplify the structure of a pixel circuit and increase the PPI.

The present application provides a pixel circuit. The pixel circuit includes a voltage control circuit, a current control circuit and a light-emitting circuit. The voltage control circuit includes a first driving circuit, a coupling circuit and a first voltage write circuit, where the first voltage write circuit is configured to transmit a voltage at a fixed level to a control terminal of the first driving circuit, the coupling circuit is configured to couple a first data voltage and a sweep signal to the control terminal of the first driving circuit, the first driving circuit is connected between a first power line and a control terminal of the current control circuit, a voltage transmitted by the first power line is a jump voltage, and the first driving circuit is configured to control a voltage of the control terminal of the current control circuit according to the first data voltage and the sweep signal to control a light emission time of a light-emitting circuit. The current control circuit and the light-emitting circuit are connected between a second power line and a third power line, and the current control circuit is configured to drive the light-emitting circuit to emit light. The voltage control circuit further includes a reset circuit, and the reset circuit is connected between the first power line and the control terminal of the current control circuit and configured to reset the voltage of the control terminal of the current control circuit; or the coupling circuit is further configured to couple a reset signal to the control terminal of the first driving circuit to reset the voltage of the control terminal of the current control circuit.

The present application further provides a driving method for a pixel circuit. The pixel circuit includes a voltage control circuit, a current control circuit and a light-emitting circuit. The voltage control circuit includes a first driving circuit, a coupling circuit and a first voltage write circuit; or the voltage control circuit includes a first driving circuit, a coupling circuit, a first voltage write circuit and a reset circuit, where the reset circuit is connected between a first power line and a control terminal of the current control circuit. The coupling circuit and the first voltage write circuit are connected to a control terminal of the first driving circuit. The first driving circuit is connected between the first power line and the control terminal of the current control circuit. A voltage transmitted by the first power line is a jump voltage. The current control circuit and the light-emitting circuit are connected between a second power line and a third power line.

The driving method for the pixel circuit includes: in a voltage write stage, controlling the first voltage write circuit to write a voltage at a fixed level to the control terminal of the first driving circuit and controlling a first data voltage to be written to the coupling circuit; in a reset stage, controlling the voltage transmitted by the first power line to jump and controlling the reset circuit to reset a voltage of the control terminal of the current control circuit, or controlling the voltage transmitted by the first power line to jump and controlling the coupling circuit to couple a reset signal to the control terminal of the first driving circuit to reset a voltage of the control terminal of the current control circuit; in a voltage normalization stage, controlling a sweep signal to be written to the coupling circuit so that the coupling circuit couples the first data voltage to the control terminal of the first driving circuit; and in a light emission stage, controlling the current control circuit to drive the light-emitting circuit to emit light and controlling a voltage of the control terminal of the first driving circuit and the voltage of the control terminal of the current control circuit through the sweep signal and the first data voltage to control a light emission time of the light-emitting circuit.

The present application further provides a display device including the pixel circuit according to any embodiment of the present application.

DETAILED DESCRIPTION

The technical solutions in embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

It is to be noted that terms such as “first” and “second” in the description, claims and drawings of the present application are used to distinguish between similar objects and are not necessarily used to describe a particular order or sequence. It is to be understood that data used in this manner are interchangeable where appropriate so that the embodiments of the present application described herein can be implemented in an order not illustrated or described herein. Additionally, terms “including” and “having” and any variations thereof are intended to encompass a non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or circuits includes not only the expressly listed steps or circuits but may also include other steps or circuits that are not expressly listed or are inherent to such process, method, system, product or device.

FIG.1is a structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.1, the pixel circuit provided in this embodiment includes a voltage control circuit10, a current control circuit20and a light-emitting circuit30. The voltage control circuit10includes a first driving circuit101, a coupling circuit102, a first voltage write circuit103and a reset circuit104. The first voltage write circuit103is configured to transmit a voltage at a fixed level to a control terminal G1of the first driving circuit101. The coupling circuit102is configured to couple a first data voltage Vdata_t and a sweep signal SWEEP to the control terminal G1of the first driving circuit101. The first driving circuit101is connected between a first power line L1and a control terminal of the current control circuit20. The first driving circuit101is configured to control a voltage of the control terminal of the current control circuit20according to the first data voltage Vdata_t and the sweep signal SWEEP to control a light emission time of the light-emitting circuit30. The current control circuit20and the light-emitting circuit30are connected between a second power line L2and a third power line L3. The reset circuit104is configured to reset the voltage of the control terminal of the current control circuit20.

For example, the current control circuit20and the light-emitting circuit30are connected between the second power line L2and the third power line L3, the second power line L2is configured to transmit a second power voltage VDDA, and the third power line L3is configured to transmit a third power voltage VSS. When a discharge path between the second power line L2and the third power line L3is turned on, the current control circuit20can generate a driving current to drive the light-emitting circuit30to emit light. A first terminal N1of the first driving circuit101is connected to the control terminal of the current control circuit20and a second terminal N2of the first driving circuit101is connected to a voltage transmitted by the first power line L1. The first driving circuit101controls a voltage of the first terminal N1of the first driving circuit101according to the first data voltage Vdata_t and the sweep signal SWEEP written to the control terminal G1of the first driving circuit101to control the voltage of the control terminal of the current control circuit20. The current control circuit20controls an on state of the discharge path between the second power line L2and the third power line L3according to the voltage of the control terminal of the current control circuit20to control the light emission time of the light-emitting circuit30.

The reset circuit104may be connected to a second voltage V2to reset a potential of the control terminal of the current control circuit20through the second voltage V2. In this embodiment, the second voltage V2may be provided by a power line. For example, the second voltage V2may be a voltage provided by the first power line L1or a voltage at a fixed level and provided by another power line.

In this embodiment, since the first data voltage Vdata_t is written to a first terminal of the coupling circuit102and a second terminal of the coupling circuit102maintains a constant voltage (which may be a fixed voltage, a first voltage V1, written by the first voltage write circuit103or may be another voltage that can make the first driving circuit101off), a voltage difference exists between the first terminal of the coupling circuit102and the second terminal of the coupling circuit102. When signal scanning is performed through the sweep signal SWEEP, a voltage of the first terminal of the coupling circuit102changes from the first data voltage Vdata_t to the sweep signal SWEEP, and under the coupling of the coupling circuit102, a voltage variation of the first terminal of the coupling circuit102is coupled to the second terminal of the coupling circuit102(the voltage after coupling does not make the first driving circuit101on). Therefore, the voltage of the second terminal of the coupling circuit102is associated with the first data voltage Vdata_t. That is, the first data voltage Vdata_t is written to the control terminal G1of the first driving circuit101. Since the first data voltage Vdata_t is written to the control terminal G1of the first driving circuit101through the coupling circuit102, no requirement is imposed on a magnitude of a first power voltage VDDW transmitted by the first power line L1connected to the second terminal N2of the first driving circuit101. Therefore, after the first data voltage Vdata_t is written to the control terminal G1of the first driving circuit101, the first driving circuit101is still in an off state and does not affect the voltage of the first terminal N1of the first driving circuit101. Thus, when an on state of the first driving circuit101is controlled, the magnitude of the first power voltage VDDW does not need to be set according to the first data voltage Vdata_t. In other words, the first power voltage VDDW does not need to vary with the first data voltage Vdata_t, facilitating a decrease in a voltage difference between voltages of a pixel (where the voltage difference refers to a voltage difference between a maximum value and a minimum value of other voltage signals than the data voltage in the pixel circuit), so that multiple devices are subjected to a relatively small bias voltage and the reliability of the pixel circuit can be improved.

FIG.2is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.2, based on the preceding technical solutions, optionally, in this embodiment, the voltage transmitted by the first power line L1is a jump voltage. For example, in this embodiment, the first power line L1may be configured to transmit a voltage that jumps from the first power voltage VDDW to a reset voltage VREF at least in a reset stage and jumps from the reset voltage VREF to the first power voltage VDDW after the reset stage.

The voltage transmitted by the first power line L1is different from the voltage transmitted by the second power line L2. In this embodiment, the second power voltage VDDA transmitted by the second power line L2is a fixed voltage, and the second power voltage VDDA is provided for the current control circuit20as a power voltage. The reset circuit104may be connected to the first power line L1. In the reset stage, the voltage transmitted by the first power line L1is the reset voltage VREF. The reset voltage VREF is the second voltage V2. The reset voltage VREF is transmitted by the reset circuit104to the control terminal of the current control circuit20to implement the function of resetting the voltage of the control terminal of the current control circuit20. After the reset stage, the voltage transmitted by the first power line L1jumps to the first power voltage VDDW. That is, the first power line L1transmits different voltages in different stages to implement different functions of the pixel circuit so that the number of signal lines can be reduced, thereby facilitating the simplification of the circuit structure, saving layout space, and achieving high PPI. The first power voltage VDDW and the reset voltage VREF are two voltages of different magnitudes.

Optionally, a minimum voltage of the reset voltage VREF is lower than a minimum voltage of the first data voltage Vdata_t.

In the pixel circuit according to the embodiment of the present application, in one aspect, the voltages transmitted by the first power line and the second power line are distinguished from each other, and the voltage transmitted by the first power line is configured to be the jump voltage. For example, the first power line is configured to transmit the reset voltage in the reset stage and transmit the first power voltage after the reset stage so that the number of power lines can be reduced, which is conducive to saving the layout space and increasing the PPI. In another aspect, the first data voltage is indirectly written to the control terminal of the first driving circuit through the coupling circuit so that the on state of the first driving circuit does not need to be set according to a magnitude of the first data voltage, and no requirement is imposed on the magnitudes of the first data voltage and the power voltage (such as the first power voltage) connected to the second terminal of the first driving circuit. The first power voltage can be flexibly set so that the voltage difference between voltages of the pixel can be reduced, and the devices are subjected to a smaller bias voltage, facilitating the improvement of the reliability of the pixel circuit.

FIG.3is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.3, based on the preceding embodiments, a first terminal of the first voltage write circuit103is connected to the first power line L1, a second terminal of the first voltage write circuit103is connected to the control terminal G1of the first driving circuit101, and the first voltage write circuit103is configured to write the first power voltage VDDW to the control terminal G1of the first driving circuit101in a voltage write stage.

For example, the fixed voltage V1transmitted by the first voltage write circuit103to the control terminal G1of the first driving circuit101may be the first power voltage VDDW transmitted by the first power line L1. In a voltage write stage, the first power line L1transmits the first power voltage VDDW, the first voltage write circuit103is turned on to transmit the first power voltage VDDW to the control terminal G1of the first driving circuit101, and the first driving circuit101is in the off state. Moreover, the first data voltage Vdata_t is written to the first terminal of the coupling circuit102, and the voltage difference between the first terminal of the coupling circuit102and the second terminal of the coupling circuit102is VDDW−Vdata_t.

Still referring toFIG.3, the coupling circuit102includes a first capacitor C1and a fourth capacitor C4, the first capacitor C1is connected between a first data line DATA1and the control terminal G1of the first driving circuit101, and the fourth capacitor C4is connected between a sweep signal line and the control terminal G1of the first driving circuit101. In the voltage write stage, the first power voltage VDDW is written to the control terminal G1of the first driving circuit101through the first voltage write circuit103, and the first data voltage Vdata_t transmitted by the first data line DATA1is written to a first terminal of the first capacitor C1, and a voltage difference between the first terminal of the first capacitor C1and a second terminal of the first capacitor C1is VDDW−Vdata_t. In a voltage normalization stage, the voltage on the first data line DATA1changes, and under the coupling of the first capacitor C1, the first data voltage Vdata_t is written to the control terminal G1of the first driving circuit101. In a light emission stage, under the coupling of the fourth capacitor C4, the voltage of the control terminal G1of the first driving circuit101is adjusted through the sweep signal SWEEP transmitted by the sweep signal line, and the first driving circuit101controls the voltage of the control terminal of the current control circuit20according to the voltage of the control terminal G1of the first driving circuit101to control the light emission time of the light-emitting circuit30.

In an optional implementation of this embodiment, to further reduce the number of signal lines, the first data voltage Vdata_t and the sweep signal SWEEP may be transmitted by the same signal line.FIG.4is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.4, the coupling circuit includes the first capacitor, the first terminal of the first capacitor C1serves as the first terminal of the coupling circuit102and is connected to the first data line DATA1, the second terminal of the first capacitor C1serves as the second terminal of the coupling circuit102and is connected to the control terminal G1of the first driving circuit101, and the first data voltage Vdata_t and the sweep signal SWEEP share the first data line DATA1. In this manner, the number of sweep signal lines and the number of capacitors can be reduced, facilitating the further reduction of the occupied layout space and achieving the high PPI. A specific operating process of the coupling circuit102is described in the subsequent embodiments.

In this embodiment, no matter whether the first data voltage Vdata_t and the sweep signal SWEEP share the same data line or use respective data lines, a switch element for switching between the first data voltage Vdata_t and the sweep signal SWEEP is not needed, facilitating the simplification of the circuit structure and the reduction of a system cost.

FIG.5is another structure diagram of a pixel circuit according to an embodiment of the present application.FIG.6is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIGS.5and6, based on the preceding embodiments, the voltage control circuit10further includes a first compensation circuit105, a first terminal of the first compensation circuit105is connected to the first terminal N1of the first driving circuit101, a second terminal of the first compensation circuit105is connected to the control terminal G1of the first driving circuit101, and the first compensation circuit105is configured to perform compensation on a threshold voltage of the first driving circuit101in the voltage write stage. The first terminal of the first voltage write circuit103is connected to a first initialization signal line, the second terminal of the first voltage write circuit103is connected to the control terminal G1of the first driving circuit101, and the first voltage write circuit103is configured to write a first initialization voltage Vinit1transmitted by the first initialization signal line to the control terminal G1of the first driving circuit101.

Compared with the pixel circuit inFIG.4, the pixel circuit shown inFIG.6has the first compensation circuit105added, and the first compensation circuit105is configured to perform threshold compensation on the first driving circuit101to improve the reliability of control of the current control circuit20. The first voltage write circuit103is configured to transmit the first initialization voltage Vinit1on the first initialization signal line.

The first driving circuit101includes a first transistor M1, the first voltage write circuit103includes a second transistor M2, the first compensation circuit105includes a third transistor M3, and the reset circuit104includes a twelfth transistor M12. A first electrode of the first transistor M1is connected to the first power line L1, a second electrode of the first transistor M1is connected to the control terminal of the current control circuit20, and a gate of the first transistor M1is connected to the coupling circuit102. A gate of the second transistor M2is connected to a first scanning signal line, a first electrode of the second transistor M2is connected to the first initialization signal line, and a second electrode of the second transistor M2is connected to the gate of the first transistor M1. A gate of the third transistor M3is connected to a second scanning signal line, a first electrode of the third transistor M3is connected to the second electrode of the first transistor M1, and a second electrode of the third transistor M3is connected to the gate of the first transistor M1. A gate of the twelfth transistor M12is connected to a reset signal line, a first electrode of the twelfth transistor M12is connected to the first power line L1, and a second electrode of the twelfth transistor M12is connected to the control terminal of the current control circuit20.

In the voltage write stage, the second transistor M2is turned on in response to a first scanning signal S1transmitted by the first scanning signal line to transmit the first initialization voltage Vinit1to the gate of the first transistor M1so that a potential of the gate of the first transistor M1is initialized, thereby preventing a residual voltage of a previous frame from affecting the light emission of a current frame. At this time, the first transistor M1is in the on state. Then, the third transistor M3is turned on in response to a second scanning signal S2transmitted by the second scanning signal line so that the first power voltage VDDW transmitted by the first power line L1charges the gate of the first transistor M1through the first transistor M1and the third transistor M3until the potential of the gate of the first transistor M1is VDDW+Vth1, and the first transistor M1is turned off, where Vth1denotes the threshold voltage of the first transistor M1. Moreover, the first data voltage Vdata_t is written to the first terminal of the first capacitor C1(with the coupling circuit102including only the first capacitor C1as an example), and the voltage difference between the first terminal of the first capacitor C1and the second terminal of the first capacitor C1is VDDW+Vth1−Vdata_t.

After the first data voltage Vdata_t is written, the reset stage begins. The voltage transmitted by the first power line L1changes from the first power voltage VDDW to the reset voltage VREF, and the twelfth transistor M12is turned on in response to a reset signal Set transmitted by the reset signal line to transmit the reset voltage VREF to the control terminal of the current control circuit20so that a discharge path between an internal circuit of the current control circuit20and the second power line L2is turned on, and the second power voltage VDDA can be transmitted to the interior of the current control circuit20to prepare for the subsequent light emission.

Then, in the voltage normalization stage, the voltage transmitted by the first data line DATA1jumps from the first data voltage Vdata_t to the sweep signal SWEEP and remains at a high level of the sweep signal SWEEP, where the high level of the sweep signal SWEEP is higher than or equal to a maximum value of the first data voltage Vdata_t. A potential of the first terminal of the first capacitor C1is pulled up. Under the coupling of the first capacitor C1, the potential of the gate of the first transistor M1(that is, the potential of point G1) is SWEEP_H+VDDW+Vth1−Vdata_t, where SWEEP_H denotes the high level of the sweep signal SWEEP. That is, the first data voltage Vdata_t is coupled to the gate of the first transistor M1.

In this embodiment, in a normal operating process of the pixel circuit, a low voltage of the first data voltage Vdata_t corresponds to a high grayscale. The lower the first data voltage Vdata_t, the higher the potential of the gate of the first transistor M1. At a constant scanning frequency of the sweep signal SWEEP, the longer the light emission time of the light-emitting circuit30, the higher the display grayscale. Therefore, the first data voltage Vdata_t is written to the gate of the first transistor M1by being coupled, and the first data voltage Vdata_t is pulled up in the voltage normalization stage. Since a low level of the first data voltage Vdata_t corresponds to a high grayscale, the first data voltage Vdata_t has a large available voltage range and the number of color scales is large, facilitating the development of grayscales.

FIG.7is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.7, based on the preceding technical solutions, optionally, the first scanning signal line also serves as the first initialization signal line. That is, the second transistor M2is diode-connected: the first electrode of the second transistor M2is connected to the first scanning signal line, and the first scanning signal line provides the first initialization voltage Vinit1so that the number of first initialization signal lines can be reduced, facilitating the further reduction of the occupied layout space of the pixel circuit and increasing the PPI. For a operating process of the pixel circuit shown inFIG.7, refer to the related description ofFIG.6, and the details are not repeated here.

FIG.8is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.8, based on the preceding technical solutions, optionally, the current control circuit20includes a first light emission control circuit201and a first storage circuit202, a control terminal of the first light emission control circuit201serves as the control terminal of the current control circuit20and is connected to the first terminal N1of the first driving circuit101, and the first storage circuit202is connected to the control terminal of the first light emission control circuit201. The current control circuit20further includes a second driving circuit203, a second voltage write circuit204, a second storage circuit205and a second light emission control circuit208. The second voltage write circuit204is connected between a second data line DATA2and a control terminal G2of the second driving circuit203, a first terminal of the first light emission control circuit201is connected to the second power voltage VDDA transmitted by the second power line L2, a second terminal of the first light emission control circuit201is connected to a first terminal of the second driving circuit203, and a second terminal of the second driving circuit203is connected to the light-emitting circuit30through the second light emission control circuit208.

The second voltage write circuit204is configured to write a second data voltage Vdata_I transmitted by the second data line DATA2to the control terminal G2of the second driving circuit203in the voltage write stage, and the second storage circuit205is connected to the control terminal G2of the second driving circuit203to store a voltage of the control terminal G2of the second driving circuit203. The second light emission control circuit208and the first light emission control circuit201are configured to control the on state of the discharge path between the second power line L2and the light-emitting circuit30.

FIG.9is another structure diagram of a pixel circuit according to an embodiment of the present application.FIG.10is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.9, based on the preceding technical solutions, optionally, the current control circuit20further includes an initialization circuit206and a second compensation circuit207, the second compensation circuit207is connected between the control terminal G2of the second driving circuit203and the second terminal of the second driving circuit203, and the initialization circuit206is configured to write a second initialization voltage Vinit2transmitted by a second initialization signal line to the control terminal G2of the second driving circuit206.

Referring toFIG.10, the first light emission control circuit201includes a fourth transistor M4, the second driving circuit203includes a fifth transistor M5, the second voltage write circuit204includes a sixth transistor M6, the initialization circuit206includes a seventh transistor M7, the second compensation circuit207includes an eighth transistor M8, the second light emission control circuit208includes a ninth transistor M9, the first storage circuit202includes a second capacitor C2, the second storage circuit205includes a third capacitor C3, and the light-emitting circuit30includes a light-emitting diode (LED).

A gate of the fourth transistor M4is connected to the first terminal N1of the first driving circuit101, a first electrode of the fourth transistor M4is connected to the second power line L2, and a second electrode of the fourth transistor M4is connected to a first electrode of the fifth transistor M5. A second electrode of the fifth transistor M5is connected to a first electrode of the ninth transistor M9, a second electrode of the ninth transistor M9is connected to a first electrode of the LED, a second electrode of the LED is connected to the third power line L3, and a gate of the ninth transistor M9is connected to a first light emission control signal line. A gate of the sixth transistor M6and a gate of the eighth transistor M8are connected to the first scanning signal line, a first electrode of the sixth transistor M6is connected to the second data line DATA2, a second electrode of the sixth transistor M6is connected to the first electrode of the fifth transistor M5, a first electrode of the eighth transistor M8is connected to a gate of the fifth transistor M5, and a second electrode of the eighth transistor M8is connected to the second electrode of the fifth transistor M5. A gate of the seventh transistor M7is connected to a third scanning signal line, a first electrode of the seventh transistor M7is connected to the second initialization signal line, and a second electrode of the seventh transistor M7is connected to the gate of the fifth transistor M5.

A first electrode of the second capacitor C2and a first electrode of the third capacitor C3are connected to the first electrode of the fourth transistor M4, a second electrode of the second capacitor C2is connected to the gate of the fourth transistor M4, and a second electrode of the third capacitor C3is connected to the gate of the fifth transistor M5.

FIG.11is a timing graph of a pixel circuit according to an embodiment of the present application, which is applicable to the pixel circuit shown inFIG.10. In conjunction withFIGS.10and11, an example in which all the transistors are p-type transistors is used, and the operating process of the pixel circuit according to the embodiment of the present application includes at least a voltage write stage T1, a reset stage T2, a voltage normalization stage T3and a light emission stage T4, where the voltage write stage T1includes at least an initialization stage t1, a second voltage write stage t2and a first voltage write stage t3.

In the initialization stage t1, the reset signal line is configured to transmit the reset signal Set at the logic high level, the third scanning signal line is configured to transmit a third scanning signal S3at the logic low level, the second scanning signal line is configured to transmit the second scanning signal S2at the logic high level, the first scanning signal line is configured to transmit the first scanning signal S1at the logic high level, and the first light emission control signal line is configured to transmit a first light emission control signal EM1at the logic high level. The seventh transistor M7is turned on, and the second initialization voltage Vinit2transmitted by the second initialization signal line is written to the gate of the fifth transistor M5to initialize a potential of the gate of the fifth transistor M5.

In the second voltage write stage t2, the reset signal line is configured to transmit the reset signal Set at the logic high level, the third scanning signal line is configured to transmit the third scanning signal S3at the logic high level, the second scanning signal line is configured to transmit the second scanning signal S2at the logic high level, the first scanning signal line is configured to transmit the first scanning signal S1at the logic low level, and the first light emission control signal line is configured to transmit the first light emission control signal EM1at the logic high level. The sixth transistor M6, the eighth transistor M8and the second transistor M2are turned on. The second data voltage Vdata_I is written to the gate of the fifth transistor M5through the sixth transistor M6, the fifth transistor M5and the eighth transistor M8so that the potential of the gate of the fifth transistor M5is Vdata_I+Vth5and is stored in the third capacitor C3, where Vth5denotes a threshold voltage of the fifth transistor M5, thereby implementing threshold compensation on the fifth transistor M5. The first initialization voltage Vinit1transmitted by the first initialization signal line is written to the gate of the first transistor M1through the second transistor M2to initialize the potential of the gate of the first transistor M1.

In the first voltage write stage t3, the reset signal line is configured to transmit the reset signal Set at the logic high level, the third scanning signal line is configured to transmit the third scanning signal S3at the logic high level, the second scanning signal line is configured to transmit the second scanning signal S2at the logic low level, the first scanning signal line is configured to transmit the first scanning signal S1at the logic high level, and the first light emission control signal line is configured to transmit the first light emission control signal EM1at the logic high level. The third transistor M3is turned on, and the first power voltage VDDW transmitted by the first power line L1charges the gate of the first transistor M1until the potential of the gate of the first transistor M1is VDDW+Vth1, and the first transistor M1is turned off. The potential of the gate of the first transistor M1is stabilized at VDDW+Vth1, thereby implementing the threshold compensation on the first transistor M1, where Vth1denotes the threshold voltage of the first transistor M1. The first data voltage Vdata_t transmitted by the first data line DATA1is written to the first terminal of the first capacitor C1, and the voltage difference between the first terminal of the first capacitor C1and the second terminal of the first capacitor C1is VDDW+Vth1−Vdata_t.

In a stage t4, the remaining multiple rows of sub-pixels undergo the initialization stage t1, the second voltage write stage t2and the first voltage write stage t3row by row to complete the data writing of all pixel rows.

In the reset stage T2, the voltage transmitted by the first power line L1jumps from the first power voltage VDDW to the reset voltage VREF, the reset signal line is configured to transmit the reset signal Set at the logic low level, the third scanning signal line is configured to transmit the third scanning signal S3at the logic high level, the second scanning signal line is configured to transmit the second scanning signal S2at the logic high level, the first scanning signal line is configured to transmit the first scanning signal S1at the logic high level, and the first light emission control signal line is configured to transmit the first light emission control signal EM1at the logic high level. The twelfth transistor M12is turned on, and the reset voltage VREF transmitted by the first power line L1is transmitted to the gate of the fourth transistor M4to control the fourth transistor M4to be turned on so that the second power voltage VDDA transmitted by the second power line L2is transmitted to the first electrode of the fifth transistor M5.

In the voltage normalization stage T3, the first data voltage Vdata_t transmitted by the first data line DATA1jumps to the high level SWEEP-H of the sweep signal SWEEP. In this embodiment, the high level SWEEP-H of the sweep signal SWEEP is higher than or equal to the maximum value of the first data voltage Vdata_t. A voltage of the first terminal of the first capacitor C1is pulled up to SWEEP-H, a voltage of the second terminal of the first capacitor C1becomes VDDW+Vth1−Vdata_t+SWEEP-H, and the first transistor M1is turned off. The reset voltage VREF transmitted by the first power line L1jumps to the first power voltage VDDW. In this case, although the first transistor M1is in the off state, the fourth transistor M4remains in the on state since the reset voltage VREF has been stored in the second capacitor C2.

In the light emission stage T4, the reset signal line is configured to transmit the reset signal Set at the logic high level, the third scanning signal line is configured to transmit the third scanning signal S3at the logic high level, the second scanning signal line is configured to transmit the second scanning signal S2at the logic high level, the first scanning signal line is configured to transmit the first scanning signal S1at the logic high level, and the first light emission control signal line is configured to transmit the first light emission control signal EM1at the logic low level. The ninth transistor M9is turned on, the discharge path between the second power line L2and the third power line L3is turned on, and the fifth transistor M5outputs a driving current according to the second data voltage Vdata_I at the gate of the fifth transistor M5to drive the light-emitting circuit30to emit light. The driving current may be expressed by the following formula:

In the above formula, u denotes an electron mobility of the fifth transistor M5, Cox denotes channel capacitance in a unit area of the fifth transistor M5, W/L demotes a width-to-length ratio of the fifth transistor M5, and Vth5denotes the threshold voltage of the fifth transistor M5. In this embodiment, the light-emitting circuit30may include one or more of an organic light-emitting diode (OLED), a micro light-emitting diode (microLED) and a mini light-emitting diode (mini LED).

In the light emission stage T4, the sweep signal SWEEP gradually changes from the high level SWEEP-H to a low level SWEEP-L. Under the coupling of the first capacitor C1, the potential of the gate of the first transistor M1changes synchronously. When the sweep signal SWEEP decreases so that the potential VG1of the gate of the first transistor M1satisfies that VG1−VDDW=Vth1, the first transistor M1is turned on, and the first power voltage VDDW is transmitted to the gate of the fourth transistor M4through the first transistor M1to control the fourth transistor M4to be turned off. Therefore, the second electrode of the fourth transistor M4is disconnected from the second power line L2, the driving current is zero, and the light-emitting circuit30stops emitting light, thereby controlling the light emission time.

Optionally, according to the technical solutions in this embodiment, the setting of one time of data writing and multiple times of light emission can be achieved in one frame, which is conducive to solving the problem of flicker at a low grayscale.FIG.12is another timing graph of a pixel circuit according to an embodiment of the present application, which is also applicable to the pixel circuit shown inFIG.10.

In this embodiment, a magnitude of the driving current depends on a magnitude of the second data voltage Vdata_I and is irrelevant to the threshold voltage Vth5of the fifth transistor M5, facilitating the improvement of uniformity of chromaticity of the light-emitting circuit30. The light emission time of the light-emitting circuit30depends on the first data voltage Vdata_t and the sweep signal SWEEP. When the sweep signal SWEEP is at the high level, the light-emitting circuit130is in a bright state. In a scanning process of the sweep signal SWEEP from the high level to the low level, the voltage of the first terminal of the first capacitor C1gradually decreases. Under the coupling of the capacitor, the voltage of the gate of the first transistor M1gradually decreases. When the potential VG1of the gate of the first transistor M1satisfies that VG1−VDDW=Vth1, the first transistor M1is turned on, and the first power voltage VDDW is transmitted to the gate of the fourth transistor M4so that the fourth transistor M4is turned off, and the light-emitting circuit30is in a dark state. As shown inFIG.12, in the light emission stage of one display frame, the sweep signal SWEEP includes multiple sub-signals, each sub-signal corresponds to one light emission sub-stage, and each sub-signal of the sweep signal SWEEP repeats the above operation process. Thus, a slope of the sweep signal SWEEP and the bright-dark switching speed of the light-emitting circuit30can be increased, facilitating the improvement of poor display due to a very slow switching speed of the light-emitting circuit30from the bright state to the dark state at a low grayscale. The sweep signal SWEEP may be a ramp signal such as a sawtooth wave or a triangle wave.

Optionally, in this embodiment, the first initialization signal line may also serve as the second initialization signal line, and the first voltage write circuit103and the initialization circuit206are connected to the first initialization voltage Vinit1so that the number of second initialization signal lines can be reduced, facilitating the reduction of the occupied layout space of the pixel circuit and increasing the PPI.

FIG.13is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.13, based on the preceding technical solutions, optionally, the third scanning signal line also serves as the second initialization signal line, that is, the seventh transistor M7is diode-connected: the first electrode of the seventh transistor M7is connected to the third scanning signal line, and the third scanning signal line provides the second initialization voltage Vinit2so that the number of second initialization signal lines can be reduced, facilitating the further reduction of the occupied layout space of the pixel circuit and increasing the PPI. For a operating process of the pixel circuit shown inFIG.13, refer to the related description ofFIG.10, and the details are not repeated here.

FIG.14is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.14, based on the preceding technical solutions, optionally, the pixel circuit further includes a third voltage write circuit106, the third voltage write circuit106is connected between the first power line L1and the second terminal of the first driving circuit101, and the third voltage write circuit106is configured to transmit the voltage transmitted by the first power line L1to the second terminal of the first driving circuit101.

Due to an on-state capacitor between the gate of the first transistor M1and the first electrode of the first transistor M1, when the second electrode of the first transistor M1is directly connected to the first power line L1, the on-state capacitor is also directly connected to the first power line L1. After the data writing, charges flow through the on-state capacitor and thus affect a charge or discharge rate of the gate of the first transistor M1, which reduces the accuracy of control of the light emission time and is not conducive to the development of grayscales. The third voltage write circuit106is disposed so that after the data writing, the on-state capacitor can be put in a floating state, which is equivalent to no capacitor at the gate of the first transistor M1, so that the charge or discharge rate of the first transistor M1is not affected, and the light emission time of the light-emitting circuit30can be better controlled.

For example, the third voltage write circuit106includes a tenth transistor M10and an eleventh transistor M11. A gate of the tenth transistor M10is connected to the second scanning signal line, a first electrode of the tenth transistor M10is connected to the first power line L1, a second electrode of the tenth transistor M10is connected to the second terminal N2of the first driving circuit101. A gate of the eleventh transistor M11is connected to a second light emission control signal line, a first electrode of the eleventh transistor M11is connected to the first power line L1, and a second electrode of the eleventh transistor M11is connected to the second terminal N2of the first driving circuit101.

In this embodiment, the first electrode of the twelfth transistor M12may be directly connected to the first power line L1or connected to the second electrode of the eleventh transistor M11. Whether to turn on the eleventh transistor M11in the reset stage T2may be selected according to a connection situation of the twelfth transistor M12.FIG.15is another timing graph of a pixel circuit according to an embodiment of the present application. Referring toFIG.15, using an example in which the first electrode of the twelfth transistor M12is connected to the second electrode of the eleventh transistor M11(that is, node N2), in the reset stage T2, the voltage transmitted by the first power line L1jumps from the first power voltage VDDW to the reset voltage VREF, a second light emission control signal EM2at a low level and transmitted by the second light emission control signal line controls the eleventh transistor M11to be turned on, and the reset voltage VREF transmitted by the first power line L1is transmitted to the gate of the fourth transistor M4through the eleventh transistor M11and the twelfth transistor M12to control the fourth transistor M4to be turned on so that the second power voltage VDDA transmitted by the second power line L2is transmitted to the first electrode of the fifth transistor M5. In the initialization stage t1, the second voltage write stage t2and the stage t4, since the tenth transistor M10and the eleventh transistor M11are turned off, the on-state capacitor does not exist between the gate of the first transistor M1and the first electrode of the first transistor M1(between node G1and node N2) so that the charge or discharge rate of the first transistor M1is not affected, and the accuracy of the voltage of the gate of the first transistor M1can be ensured.

Optionally, the present application further provides a driving method for a pixel circuit, where the pixel circuit according to any embodiment of the present application can be driven by the driving method. In conjunction withFIG.1, the pixel circuit includes a voltage control circuit10, a current control circuit20and a light-emitting circuit30. The voltage control circuit10includes a first driving circuit101, a coupling circuit102, a first voltage write circuit103and a reset circuit104. The coupling circuit102and the first voltage write circuit103are connected to a control terminal G1of the first driving circuit101. The first driving circuit101is connected between a first power line L1and a control terminal of the current control circuit20. The current control circuit20and the light-emitting circuit30are connected between a second power line L2and a third power line L3.FIG.16is a flowchart of a driving method for a pixel circuit according to an embodiment of the present application. Referring toFIG.16, the driving method for the pixel circuit includes S110to S140.

In S110, in a voltage write stage, the first voltage write circuit is controlled to write a voltage at a fixed level to the control terminal of the first driving circuit and a first data voltage is controlled to be written to the coupling circuit.

In S120, in a reset stage, the reset circuit is controlled to reset a voltage of the control terminal of the current control circuit.

In S130, in a voltage normalization stage, a sweep signal is controlled to be written to the coupling circuit so that the coupling circuit couples the first data voltage to the control terminal of the first driving circuit.

In S140, in a light emission stage, the current control circuit is controlled to drive the light-emitting circuit to emit light, and a voltage of the control terminal of the first driving circuit and the voltage of the control terminal of the current control circuit are controlled through the sweep signal and the first data voltage to control a light emission time of the light-emitting circuit.

In the driving method for the pixel circuit according to the embodiment of the present application, the first data voltage is indirectly written to the control terminal of the first driving circuit through the coupling circuit so that an on state of the first driving circuit does not need to be set according to a magnitude of the first data voltage, and no requirement is imposed on magnitudes of the first data voltage and a power voltage (such as a first power voltage) connected to a second terminal of the first driving circuit. The first power voltage can be flexibly set so that a voltage difference between voltages of a pixel can be reduced, and devices are subjected to a smaller bias voltage, facilitating the improvement of the reliability of the pixel circuit. Moreover, in this embodiment, no voltage write control circuit or unit is needed, and the pixel circuit is simple in structure, which is conducive to saving layout space and increasing the PPI.

In this embodiment, the reset circuit104may be connected between the first power line L1and the control terminal of the current control circuit20, and the first power line L1is configured to transmit a voltage that jumps from the first power voltage VDDW to a reset voltage VREF at least in the reset stage and jumps from the reset voltage VREF to the first power voltage VDDW after the reset stage.FIG.17shows another driving method for a pixel circuit according to an embodiment of the present application. Referring toFIG.17, the driving method for the pixel circuit includes S110to S140.

In S110, in the voltage write stage, the first voltage write circuit is controlled to write the voltage at the fixed level to the control terminal of the first driving circuit and the first data voltage is controlled to be written to the coupling circuit.

In S1201, in the reset stage, the voltage transmitted by the first power line is controlled to jump from the first power voltage to the reset voltage, and the reset circuit is controlled to write the reset voltage to the control terminal of the current control circuit.

In S1301, in the voltage normalization stage, the sweep signal is controlled to be written to the coupling circuit so that the coupling circuit couples the first data voltage to the control terminal of the first driving circuit, and the reset voltage is controlled to jump to the first power voltage.

In S140, in the light emission stage, the current control circuit is controlled to drive the light-emitting circuit to emit light, and the voltage of the control terminal of the first driving circuit and the voltage of the control terminal of the current control circuit are controlled through the sweep signal and the first data voltage to control the light emission time of the light-emitting circuit.

Still referring toFIG.10, the first voltage write circuit103is connected between a first initialization signal line and the control terminal G1of the first driving circuit101, and a control terminal of the first voltage write circuit103is connected to a first scanning signal line. The voltage control circuit10further includes a first compensation circuit105, the first compensation circuit105is connected between a first terminal N1of the first driving circuit101and the control terminal G1of the first driving circuit101, and a control terminal of the first compensation circuit105is connected to a second scanning signal line. A control terminal of the reset circuit104is connected to a reset signal line. The current control circuit20includes a first light emission control circuit201, a first storage circuit202, a second driving circuit203, a second voltage write circuit204, a second storage circuit205, an initialization circuit206, a second compensation circuit207and a second light emission control circuit208. A control terminal of the first light emission control circuit201serves as the control terminal of the current control circuit20and is connected to the first terminal N1of the first driving circuit101. The first storage circuit202is connected to the control terminal of the first light emission control circuit201. The first light emission control circuit201is connected between the second power line L2and a first terminal of the second driving circuit203. A control terminal of the second voltage write circuit204and a control terminal of the second compensation circuit207are connected to the first scanning signal line, the second voltage write circuit204is connected between a second data line DATA2and the first terminal of the second driving circuit203, and the second compensation circuit207is connected between a control terminal G2of the second driving circuit203and a second terminal of the second driving circuit203. The initialization circuit206is connected between a second initialization signal line and the control terminal G2of the second driving circuit203, and a control terminal of the initialization circuit206is connected to a third scanning signal line. A control terminal of the second light emission control circuit208is connected to a first light emission control signal line, and the second light emission control circuit208is connected between the second terminal of the second driving circuit203and the light-emitting circuit30.

In conjunction withFIG.11, in this embodiment, a voltage write stage T1includes an initialization stage t1, a second voltage write stage t2and a first voltage write stage t3.

In the initialization stage t1, a third scanning signal S3at the low level and transmitted by the third scanning signal line controls the initialization circuit206to be turned on, and a second initialization voltage Vinit2transmitted by the second initialization signal line is written to the control terminal G2of the second driving circuit203to initialize a potential of the control terminal of the second driving circuit203.

In the second voltage write stage t2, a first scanning signal S1at the low level and transmitted by the first scanning signal line controls the second voltage write circuit204, the second compensation circuit207and the first voltage write circuit103to be turned on. A second data voltage Vdata_I is written to the control terminal G2of the second driving circuit203through the second voltage write circuit204, the second driving circuit203and the second compensation circuit207so that the potential of the control terminal G2of the second driving circuit203is Vdata_I+Vth5and stored in the second storage circuit205, where Vth5denotes a threshold voltage of a fifth transistor M5, thereby implementing threshold compensation on the fifth transistor M5. Moreover, a first initialization voltage Vinit1transmitted by the first initialization signal line is written to the control terminal G1of the first driving circuit101through the first voltage write circuit103to initialize a potential of the control terminal G1of the first driving circuit101.

In the first voltage write stage t3, a second scanning signal S2at the low level and transmitted by the second scanning signal line controls the first compensation circuit105to be turned on, and the first power voltage VDDW transmitted by the first power line L1charges the control terminal G1of the first driving circuit101, thereby implementing the threshold compensation on the first driving circuit101. Moreover, the first data voltage Vdata_t transmitted by a first data line DATA1is written to a first terminal of the coupling circuit102.

In a stage t4, the remaining multiple rows of sub-pixels undergo the initialization stage t1, the second voltage write stage t2and the first voltage write stage t3row by row to complete the data writing of all pixel rows.

For specific operations in the reset stage T2, the voltage normalization stage T3and the light emission stage T4, refer to the related description in the preceding multiple embodiments. The driving method also has the effects described in the preceding multiple embodiments. The details are not repeated here.

FIG.18is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.18, the pixel circuit provided in this embodiment includes a voltage control circuit10, a current control circuit20and a light-emitting circuit30. The voltage control circuit10includes a first driving circuit101, a first voltage write circuit103and a coupling circuit102. The first voltage write circuit103is configured to transmit a voltage V1at a fixed level to a control terminal G1of the first driving circuit101. The first driving circuit101is connected between a first power line L1and a control terminal of the current control circuit20, where a voltage transmitted by the first power line L1is a jump voltage. The coupling circuit102is configured to couple a first data voltage Vdata_t and a sweep signal SWEEP to the control terminal G1of the first driving circuit101and couple a reset signal Set to the control terminal G1of the first driving circuit101. The current control circuit20and the light-emitting circuit30are connected between a second power line L2and a third power line L3. The current control circuit20is configured to drive the light-emitting circuit30to emit light. The first driving circuit101is configured to control a voltage of the control terminal of the current control circuit20according to the first data voltage Vdata_t and the sweep signal SWEEP to control a light emission time of the light-emitting circuit30.

For example, the current control circuit20and the light-emitting circuit30are connected between the second power line L2and the third power line L3, the second power line L2is configured to transmit a second power voltage VDDA, and the third power line L3is configured to transmit a third power voltage VSS. When a discharge path between the second power line L2and the third power line L3is turned on, the current control circuit20can generate a driving current to drive the light-emitting circuit30to emit light. A first terminal N1of the first driving circuit101is connected to the control terminal of the current control circuit20and a second terminal N2of the first driving circuit101is connected to the voltage transmitted by the first power line L1. The first driving circuit101controls a voltage of the first terminal N1of the first driving circuit101according to the first data voltage Vdata_t and the sweep signal SWEEP written to the control terminal G1of the first driving circuit101to control the voltage of the control terminal of the current control circuit20. The current control circuit20controls an on state of the discharge path between the second power line L2and the third power line L3according to the voltage of the control terminal of the current control circuit20to control the light emission time of the light-emitting circuit30.

In this embodiment, the voltage transmitted by the first power line L1is different from the voltage transmitted by the second power line L2, where the second power voltage VDDA transmitted by the second power line L2is at a fixed level, and the voltage transmitted by the first power line L1is the jump voltage, so as to reduce the number of signal lines.

For example, an operating process of the pixel circuit provided in this embodiment includes at least a voltage write stage, a reset stage, a voltage normalization stage and a light emission stage. The first power line L1may be configured to transmit a voltage that jumps from a first power voltage VDDW to a reset voltage VREF at least in the reset stage and jumps from the reset voltage VREF to the first power voltage VDDW after the reset stage. In the voltage write stage, the first voltage write circuit103is configured to transmit the voltage V1at the fixed level to the control terminal G1of the first driving circuit101to control a potential of the control terminal of the first driving circuit101(that is, a potential of a second terminal of the coupling circuit102). Then, the first data voltage Vdata_t is transmitted to a first terminal of the coupling circuit102, a potential difference exists between the first terminal of the coupling circuit102and the second terminal of the coupling circuit102, and the voltage transmitted by the first power line L1is the first power voltage VDDW. In the reset stage, the first power voltage VDDW transmitted by the first power line L1jumps to the reset voltage VREF, the coupling circuit102couples the reset signal Set to the control terminal G1of the first driving circuit101to control the first driving circuit101to be turned on, and the first driving circuit101transmits the reset voltage VREF to the control terminal of the current control circuit20so that the current control circuit20is conducted with the second power line L2. In the embodiment of the present application, a circuit for resetting the control terminal of the current control circuit20does not need to be disposed separately, facilitating the simplification of the circuit structure and reducing the number of signal lines. In the voltage normalization stage, the coupling circuit102couples the sweep signal SWEEP to the control terminal G1of the first driving circuit101to ensure that the first driving circuit101is in an off state, and the reset voltage VREF transmitted by the first power line L1jumps to the first power voltage VDDW. In the light emission stage, the current control circuit20is controlled to generate the driving current to drive the light-emitting circuit30to emit light. The sweep signal SWEEP is configured to perform signal scanning from a high level to a low level or perform signal scanning from a low level to a high level in the light emission stage to control an output voltage of the first driving circuit101. Thus, the voltage of the control terminal of the current control circuit20is controlled, and a working state (on or off) of the current control circuit20is controlled so that the light emission time of the light-emitting circuit30is controlled. An initial voltage of the sweep signal SWEEP in the light emission stage is the same as the voltage of the sweep signal SWEEP written to the coupling circuit102in the voltage normalization stage.

The first voltage write circuit103is connected to the first driving circuit101. The first voltage write circuit103is configured to transmit the fixed voltage V1to the control terminal G1of the first driving circuit101, where the fixed voltage V1may be at a high level or a low level and may be set according to the specific circuit structure of the first driving circuit101and actual requirements.

According to the technical solutions provided in this embodiment, the current control circuit generates the driving current to drive the light-emitting circuit to emit light, and the first driving circuit controls the voltage of the control terminal of the current control circuit to control the period in which the current control circuit is turned on to control the light emission time of the light-emitting circuit. In this embodiment, the power voltages connected to the voltage control circuit and the current control circuit are distinguished, and the power voltage transmitted by the first power line connected to the voltage control circuit is configured to be the jump voltage. In the reset stage, the first power line is configured to transmit the reset voltage, and the coupling circuit couples the reset signal to the control terminal of the first driving circuit to control the first driving circuit to be turned on so that the reset voltage is transmitted to the control terminal of the current control circuit, thereby resetting a control potential of the current control circuit. Compared with a solution where a separate reset circuit is configured to reset the control terminal of the current control circuit, the technical solutions provided in this embodiment have no need to dispose the reset circuit and a reset voltage signal line so that the structure of the pixel circuit can be simplified and the number of signal lines can be reduced, facilitating the increase of the PPI.

FIG.19is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.19, based on the preceding technical solutions, the coupling circuit102includes a first capacitor C1, a second capacitor C2and a third capacitor C3. A first terminal of the first capacitor C1is connected to a first data line DATA1and a second terminal of the first capacitor C1is connected to the control terminal G1of the first driving circuit101. The first data line DATA1is configured to transmit the first data voltage Vdata_t to the first terminal of the first capacitor C1in the voltage write stage, and the first data voltage Vdata_t is coupled to the control terminal G1of the first driving circuit101. A first terminal of the second capacitor C2is connected to a reset signal line, a second terminal of the second capacitor C2is connected to the control terminal G1of the first driving circuit101, and the reset signal line is configured to transmit the reset signal Set to the first terminal of the second capacitor C2in the reset stage. A first terminal of the third capacitor C3is connected to a sweep signal line, a second terminal of the third capacitor C3is connected to the control terminal G1of the first driving circuit101, and the sweep signal line is configured to transmit the sweep signal SWEEP to the first terminal of the third capacitor C3in the voltage normalization stage.

Optionally, the coupling circuit102may include only one capacitor, and the first data voltage Vdata_t, the reset signal Set and the sweep signal SWEEP share one signal line to further reduce the number of signal lines, facilitating the high PPI of a panel.FIG.20is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.20, the coupling circuit102includes the first capacitor C1, the first terminal of the first capacitor C1is connected to the first data line DATA1, and the second terminal of the first capacitor C1is connected to the control terminal G1of the first driving circuit101. The first data line DATA1is configured to transmit the first data voltage Vdata_t to the first terminal of the first capacitor C1in the voltage write stage, transmit the reset signal Set to the first terminal of the first capacitor C1in the reset stage, and transmit the sweep signal SWEEP to the first terminal of the first capacitor C1in the voltage normalization stage.

For example, in the voltage write stage, the first voltage write circuit103is turned on, the fixed voltage V1is written to the control terminal G1of the first driving circuit101, and the first data voltage Vdata_t transmitted by the first data line DATA1is written to the first terminal of the first capacitor C1. In this case, a voltage difference between the first terminal of the first capacitor C1and the second terminal of the first capacitor C1remains a difference between the fixed voltage V1and the first data voltage Vdata_t.

In the reset stage, the voltage transmitted by the first power line L1jumps from the first power voltage VDDW to the reset voltage VREF, and the voltage on the first data line DATA1jumps from the first data voltage Vdata_t to the reset signal Set, where the reset signal Set may be a low-level voltage. A voltage of the first terminal of the first capacitor C1is pulled down. Under the coupling of the first capacitor C1, a potential of a gate of the first driving circuit101becomes a difference between the fixed voltage V1and a voltage variation of the first terminal of the first capacitor C1, that is, the first data voltage Vdata_t is coupled to the control terminal G1of the first driving circuit101. Since the potential of the control terminal of the first driving circuit101is pulled down, the first driving circuit101is turned on, and the reset voltage VREF transmitted by the first power line L1is transmitted to the control terminal of the current control circuit20to reset a potential of the control terminal of the current control circuit20.

In the voltage normalization stage, the voltage transmitted by the first power line L1jumps from the reset voltage VREF to the first power voltage VDDW, the reset signal Set transmitted by the first data line DATA1jumps to the sweep signal SWEEP, and a potential of the first terminal of the first capacitor C1is pulled up. Under the coupling of the first capacitor C1, the potential of the control terminal G1of the first driving circuit101is pulled up so that the first driving circuit101is turned off. In this case, a voltage of the control terminal G1of the first driving circuit101is associated with the first data voltage Vdata_t.

In the light emission stage, the discharge path between the second power line L2, the current control circuit20, the light-emitting circuit30and the third power line L3is turned on, and the current control circuit20generates the driving current to drive the light-emitting circuit30to emit light. The sweep signal SWEEP gradually changes from the high level to the low level so that the potential of the first terminal of the first capacitor C1decreases. Under the coupling of the first capacitor C1, the potential of the control terminal G1of the first driving circuit101also decreases. When the potential of the control terminal G1decreases to one that makes the first driving circuit101turned on, the first power voltage VDDW is transmitted to the control terminal of the current control circuit20through the first driving circuit101, and the current control circuit20is turned off according to the voltage of the control terminal of the current control circuit20so that the current control circuit20does not output the driving current, and the light-emitting circuit30stops emitting light, thereby controlling the light emission time of the light-emitting circuit30.

In this embodiment, the first driving circuit101and the first voltage write circuit103may include transistors to implement voltage writing. For example, the first driving circuit101may include a first transistor, and the first voltage write circuit103may include a second transistor.

In the preceding multiple embodiments, since the first data voltage Vdata_t is coupled and written to the control terminal G1of the first driving circuit101through the coupling circuit102, in the operating process of the pixel circuit, the on state of the first driving circuit101is no longer affected by the voltage transmitted by the first power line L1. That is, no requirement is imposed on magnitudes of the first data voltage Vdata_t and the voltage transmitted by the first power line L1. In this manner, the voltage transmitted by the first power line L1can be maintained at a relatively low level so that a voltage difference in the pixel circuit can be reduced, facilitating the reduction of a bias voltage of multiple circuits or devices and reducing a possibility of device failure. The reset signal Set is also coupled to the control terminal G1of the first driving circuit101through the coupling circuit102. Therefore, when the voltage on the first power line L1jumps from the first power voltage VDDW to the reset voltage VREF, the voltage of the control terminal G1of the first driving circuit101can still keep the first driving circuit101in the on state so that the reset voltage VREF can be flexibly set, facilitating signal simplification.

In this embodiment, no matter whether the first data voltage Vdata_t, the reset signal Set and the sweep signal SWEEP share the same data line or use respective data lines, a switch element for switching is not needed, facilitating the simplification of the circuit structure and the reduction of a system cost.

In the following embodiments, an example in which the first data voltage Vdata_t, the reset signal Set and the sweep signal SWEEP share the first data line DATA1is used.

In this embodiment, the reset stage is positioned after the voltage write stage and before the voltage normalization stage so that the number of jumps between signal levels on the first data line DATA1can be reduced, facilitating the simplification of the control timing of the pixel circuit. A minimum voltage of the reset voltage VREF is lower than a minimum voltage of the first data voltage Vdata_t, and a maximum voltage of the sweep signal SWEEP is higher than or equal to a maximum voltage of the first data voltage Vdata_t.

Based on the preceding embodiments, the voltage control circuit10further includes a first compensation circuit105. The current control circuit20includes a first light emission control circuit201, a first storage circuit202, a second driving circuit203, a second voltage write circuit204, a second storage circuit205and a second light emission control circuit208.

Based on the preceding embodiments, the current control circuit20further includes an initialization circuit206and a second compensation circuit207.

FIG.21is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.21, based on the preceding technical solutions, the first driving circuit101includes a first transistor M1, the first voltage write circuit103includes a second transistor M2, the first compensation circuit105includes a third transistor M3, the first light emission control circuit201includes a fourth transistor M4, the second driving circuit203includes a fifth transistor M5, the second voltage write circuit204includes a sixth transistor M6, the initialization circuit206includes a seventh transistor M7, the second compensation circuit207includes an eighth transistor M8, the second light emission control circuit208includes a ninth transistor M9, the first storage circuit202includes a second capacitor C2, the second storage circuit205includes a third capacitor C3, and the light-emitting circuit30includes an LED.

For example, a first electrode of the first transistor M1is connected to the first power line L1, a second electrode of the first transistor M1is connected to a gate of the fourth transistor M4, and a gate of the first transistor M1is connected to the coupling circuit102. A gate of the second transistor M2is connected to a first scanning signal line, a first electrode of the second transistor M2is connected to a first initialization signal line, and a second electrode of the second transistor M2is connected to the gate of the first transistor M1. A gate of the third transistor M3is connected to a second scanning signal line, a first electrode of the third transistor M3is connected to the second electrode of the first transistor M1, and a second electrode of the third transistor M3is connected to the gate of the first transistor M1. A first electrode of the fourth transistor M4is connected to the second power line L2and a second electrode of the fourth transistor M4is connected to a first electrode of the fifth transistor M5. A second electrode of the fifth transistor M5is connected to a first electrode of the ninth transistor M9, a second electrode of the ninth transistor M9is connected to a first electrode of the LED, a second electrode of the LED is connected to the third power line L3, and a gate of the ninth transistor M9is connected to a first light emission control signal line. A gate of the sixth transistor M6and a gate of the eighth transistor M8are connected to the first scanning signal line, a first electrode of the sixth transistor M6is connected to a second data line DATA2, a second electrode of the sixth transistor M6is connected to the first electrode of the fifth transistor M5, a first electrode of the eighth transistor M8is connected to a gate of the fifth transistor M5, and a second electrode of the eighth transistor M8is connected to the second electrode of the fifth transistor M5. A gate of the seventh transistor M7is connected to a third scanning signal line, a first electrode of the seventh transistor M7is connected to a second initialization signal line, and a second electrode of the seventh transistor M7is connected to the gate of the fifth transistor M5. A first electrode of the second capacitor C2and a first electrode of the third capacitor C3are connected to the first electrode of the fourth transistor M4, a second electrode of the second capacitor C2is connected to the gate of the fourth transistor M4, and a second electrode of the third capacitor C3is connected to the gate of the fifth transistor M5.

FIG.22is another timing graph of a pixel circuit according to an embodiment of the present application, which is applicable to the pixel circuit shown inFIG.21. In conjunction withFIGS.21and22, an example in which all the transistors are p-type transistors is used, and the operating process of the pixel circuit according to the embodiment of the present application includes at least a voltage write stage T1, a reset stage T2, a voltage normalization stage T3and a light emission stage T4, where the voltage write stage T1includes at least an initialization stage t1, a second voltage write stage t2and a first voltage write stage t3.

The timing control of the pixel circuit in the initialization stage t1, the second voltage write stage t2, the first voltage write stage t3, a stage t4, the voltage normalization stage T3and the light emission stage T4shown inFIG.22is the same as the timing control of the pixel circuit in the initialization stage t1, the second voltage write stage t2, the first voltage write stage t3, the stage t4, the voltage normalization stage T3and the light emission stage T4shown inFIG.11, and the details are not repeated here. Only differences fromFIG.11are described.

In this embodiment, in the reset stage T2, the voltage on the first data line DATA1changes from the first data voltage Vdata_t to the reset signal Set, and the voltage of the first terminal of the first capacitor C1is pulled down. Under the coupling of the first capacitor C1, a potential of the gate of the first transistor M1is VDDW+Vth1−Vdata_t+Vset, the first transistor M1is turned on, and the reset voltage VREF transmitted by the first power line L1is transmitted to the gate of the fourth transistor M4to control the fourth transistor M4to be turned on so that the second power voltage VDDA transmitted by the second power line L2is transmitted to the first electrode of the fifth transistor M5. Moreover, the first data voltage Vdata_t and the reset signal Set are coupled and written to the gate of the first transistor M1through the first capacitor C1. Therefore, according to the technical solutions provided in this embodiment, the circuit for resetting the control terminal of the current control circuit20does not need to be disposed separately, facilitating the simplification of the circuit structure and reducing the number of signal lines.

FIG.23is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.23, based on the preceding multiple technical solutions, optionally, the pixel circuit further includes a third voltage write circuit106, the third voltage write circuit106is connected between the first power line L1and the second terminal of the first driving circuit101, and the third voltage write circuit106is configured to transmit the voltage transmitted by the first power line to the second terminal of the first driving circuit101.

The working principle of the third voltage write circuit106in the pixel circuit shown inFIG.23is the same as the working principle of the third voltage write circuit106in the pixel circuit in the embodiment ofFIG.14, and the details are not repeated here.

FIG.24is another timing graph of a pixel circuit according to an embodiment of the present application, which is applicable to the pixel circuit shown inFIG.23. The timing control of the pixel circuit in the initialization stage t1, the second voltage write stage t2, the first voltage write stage t3, the stage t4, the voltage normalization stage T3and the light emission stage T4shown inFIG.24is the same as the timing control of the pixel circuit in the initialization stage t1, the second voltage write stage t2, the first voltage write stage t3, the stage t4, the voltage normalization stage T3and the light emission stage T4shown inFIG.15, and the details are not repeated here. Only differences fromFIG.15are described. Referring toFIGS.23and24, in the reset stage T2, the voltage transmitted by the first power line L1jumps from the first power voltage VDDW to the reset voltage VREF, the voltage on the first data line DATA1jumps from the first data voltage Vdata_t to the reset signal Set, and the voltage of the first terminal of the first capacitor C1is pulled down. Under the coupling of the first capacitor C1, the first transistor M1is turned on.

FIG.25is another structure diagram of a pixel circuit according to an embodiment of the present application. Referring toFIG.25, optionally, in this embodiment, the first scanning signal line also serves as the first initialization signal line, and the third scanning signal line also serves as the second initialization signal line. That is to say, the second transistor M2and the seventh transistor M7are diode-connected so that the number of first initialization signal lines and the number of second initialization signal lines can be reduced. Of course, in other embodiments, the first initialization signal line may also serve as the second initialization signal line, or the first scanning signal line may also serve as the third scanning signal line, that is, the same initialization voltage is input through the second transistor M2and the seventh transistor M7. With the preceding related settings, the number of signal lines can be further reduced, and signal types can be simplified, facilitating the increase of the PPI. Based on the pixel circuit provided inFIG.21of the present application, in conjunction with the technical solution where the second transistor M2and the seventh transistor M7are diode-connected, the pixel circuit having a 9T3C structure can satisfy the display requirement of more than 160 PPI.

Optionally, the present application further provides a driving method for a pixel circuit, where the pixel circuit according to any embodiment of the present application can be driven by the driving method. In conjunction withFIG.18, the pixel circuit includes a voltage control circuit10, a current control circuit20and a light-emitting circuit30. The voltage control circuit10includes a first driving circuit101, a coupling circuit102and a first voltage write circuit103. The first driving circuit101is connected between a first power line L1and a control terminal of the current control circuit20. The current control circuit20and the light-emitting circuit30are connected between a second power line L2and a third power line L3. The coupling circuit102is connected to a control terminal G1of the first driving circuit101.FIG.26is another flowchart of a driving method for a pixel circuit according to an embodiment of the present application. Referring toFIG.26, the driving method for the pixel circuit includes S210to S240.

In S210, in a voltage write stage, the first voltage write circuit is controlled to write a voltage at a fixed level to the control terminal of the first driving circuit and a first data voltage is controlled to be written to the coupling circuit.

In S220, in a reset stage, a voltage transmitted by the first power line is controlled to jump, and the coupling circuit is controlled to couple a reset signal to the control terminal of the first driving circuit.

In S230, in a voltage normalization stage, a sweep signal is controlled to be written to the coupling circuit.

In S240, in a light emission stage, the current control circuit is controlled to drive the light-emitting circuit to emit light, and a voltage of the control terminal of the first driving circuit and a voltage of the control terminal of the current control circuit are controlled through the sweep signal and the first data voltage to control a light emission time of the light-emitting circuit.

According to the technical solutions provided in this embodiment, the current control circuit generates a driving current to drive the light-emitting circuit to emit light, and the first driving circuit controls the voltage of the control terminal of the current control circuit to control the period in which the current control circuit is turned on to control the light emission time of the light-emitting circuit. In this embodiment, power voltages connected to the voltage control circuit and the current control circuit are distinguished, and a power voltage transmitted by the first power line connected to the voltage control circuit is configured to be a jump voltage. In the reset stage, the voltage transmitted by the first power line jumps from a first power voltage to a reset voltage, and the coupling circuit couples the reset signal to the control terminal of the first driving circuit to control the first driving circuit to be turned on so that the reset voltage is transmitted to the control terminal of the current control circuit, thereby resetting a control potential of the current control circuit. Compared with a solution where a separate reset circuit is configured to reset the control terminal of the current control circuit, the technical solutions provided in this embodiment have no need to dispose the reset circuit and a reset voltage signal line so that the structure of the pixel circuit can be simplified and the number of signal lines can be reduced, facilitating the increase of the PPI.

Optionally, the first power line L1is configured to transmit a voltage that jumps from a first power voltage VDDW to a reset voltage VREF at least in the reset stage and jumps from the reset voltage VREF to the first power voltage VDDW after the reset stage. Referring toFIG.21, the first voltage write circuit103is connected between a first initialization signal line and the control terminal G1of the first driving circuit101, and a control terminal of the first voltage write circuit103is connected to a first scanning signal line. The voltage control circuit10further includes a first compensation circuit105, the first compensation circuit105is connected between a first terminal N1of the first driving circuit101and the control terminal G1of the first driving circuit101, and a control terminal of the first compensation circuit105is connected to a second scanning signal line. The current control circuit20includes a first light emission control circuit201and a first storage circuit202. A control terminal of the first light emission control circuit201serves as the control terminal of the current control circuit20and is connected to the first terminal of the first driving circuit101. The first storage circuit202is connected to the control terminal of the first light emission control circuit201. The current control circuit20includes a second driving circuit203, a second voltage write circuit204, a second storage circuit205, an initialization circuit206, a second light emission control circuit208and a second compensation circuit207. The first light emission control circuit201is connected between the second power line L2and a first terminal of the second driving circuit203. A control terminal of the second voltage write circuit204and a control terminal of the second compensation circuit207are connected to the first scanning signal line, the second voltage write circuit204is connected between a second data line DATA2and the first terminal of the second driving circuit203, and the second compensation circuit207is connected between a control terminal G2of the second driving circuit203and a second terminal of the second driving circuit203. The initialization circuit206is connected between a second initialization signal line and the control terminal G2of the second driving circuit203, and a control terminal of the initialization circuit206is connected to a third scanning signal line. A control terminal of the second light emission control circuit208is connected to a first light emission control signal line, and the second light emission control circuit208is connected between the second terminal of the second driving circuit203and the light-emitting circuit30.

The voltage write stage includes an initialization stage, a first voltage write stage and a second voltage write stage.FIG.27is another flowchart of a driving method for a pixel circuit according to an embodiment of the present application. Referring toFIG.27, the driving method for the pixel circuit includes S2101to S2401.

In S2101, in the initialization stage, a third scanning signal transmitted by the third scanning signal line controls the initialization circuit to be turned on to control a second initialization voltage transmitted by the second initialization signal line to be written to the control terminal of the second driving circuit.

In S2102, in the second voltage write stage, a first scanning signal transmitted by the first scanning signal line controls the second voltage write circuit and the second compensation circuit to be turned on to write a second data voltage to the control terminal of the second driving circuit and controls the first voltage write circuit to be turned on to write a first initialization voltage transmitted by the first initialization signal line to the control terminal of the first driving circuit.

In S2103, in the first voltage write stage, a second scanning signal transmitted by the second scanning signal line controls the first compensation circuit to be turned on, and the first data voltage is written to a first terminal of the coupling circuit.

In S2201, in the reset stage, the first power voltage transmitted by the first power line is controlled to jump to the reset voltage, and the coupling circuit is controlled to couple the reset signal to the control terminal of the first driving circuit.

In S2301, in the voltage normalization stage, the sweep signal is controlled to be written to the coupling circuit, and the reset voltage is controlled to jump to the first power voltage.

In S2401, in the light emission stage, a first light emission control signal transmitted by the first light emission control signal line controls the second light emission control circuit to be turned on, and the voltage of the control terminal of the first driving circuit and the voltage of the control terminal of the current control circuit are controlled through the sweep signal and the first data voltage to control the light emission time of the light-emitting circuit.

For example, the driving method for the pixel circuit shown inFIG.27is applicable to the pixel circuit shown inFIG.21. For the specific working principle, refer to the related description in the preceding multiple embodiments. The driving method also has the effects described in the preceding multiple embodiments. The details are not repeated here.

Optionally, an embodiment of the present application provides a display device. The display device includes the pixel circuit according to any embodiment of the present application.FIG.28is a structure diagram of a display device according to an embodiment of the present application. The display device may be the cellphone shown inFIG.28or may be a tablet, a mobile phone, a watch, a wearable device or an electronic device such as an in-vehicle display, a camera display, a television or a computer screen. The display device includes the pixel circuit of any embodiment of the present application; therefore, the display device of this embodiment of the present application has the effects described in any embodiment of the present application.

It is to be understood that various forms of the preceding flows may be adopted with steps reordered, added or deleted. For example, the steps described in the present application may be performed in parallel, in sequence or in a different sequence as long as the desired results of the technical solutions of the present application can be achieved. The execution sequence of the steps is not limited herein.