Pixel driving circuit and control method thereof, display panel and display equipment

Abstract

The invention discloses a pixel driving circuit and a control method thereof, a display panel and display equipment. The pixel driving circuit comprises a pixel unit and a data signal line. Each pixel unit comprises a light-emitting unit, a driving transistor and a storage capacitor for storing voltage; the voltage stored by the storage capacitor can act on the driving transistor for driving the light-emitting unit. The voltage written by the data signal line for the first time acts on the storage capacitor, so that the storage capacitor stores the voltage; the voltage of the data signal line written for the second time corresponds to the voltage of the data signal line written for the first time and is dynamically adjusted along with the voltage, and the voltage of the storage capacitor can be maintained by the voltage of the data signal line written for the second time so as to maintain the potential of the driving transistor. According to the pixel driving circuit, the voltage of the storage capacitor is maintained in a secondary writing mode so as to maintain the potential of the driving transistor, and therefore the problem that the light-emitting unit flickers or is insufficient in light-emitting brightness is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of display devices, and more specifically, to a pixel driving circuit, a display panel, a display device, and a control method for a pixel driving circuit. Background Art

[0002] The pixel driving circuit turns on the switching transistor during the data voltage writing phase to store the data voltage in the capacitor, and turns off the switching transistor during the light-emitting phase to control the gate of the driving transistor by discharging the data voltage stored in the capacitor. When the switching transistor is turned off, the data voltage in the capacitor may still leak current from the switching transistor, causing the potential of the gate of the driving transistor to decay. When the potential of the gate of the driving transistor decays, the current flowing through the driving transistor will change synchronously, and the final optical display will show flickering and insufficient brightness. Summary of the invention

[0003] Embodiments of the present invention provide a pixel driving circuit, a display panel, a display device, and a control method for the pixel driving circuit.

[0004] An embodiment of the present invention provides a pixel driving circuit, which includes a pixel unit and a data signal line. The pixel unit includes a light-emitting unit, a driving transistor and a storage capacitor; the storage capacitor is used to store a voltage, and the voltage stored in the storage capacitor can act on the driving transistor to drive the light-emitting unit. The data signal line can write a voltage twice, and the voltage written by the data signal line for the first time acts on the storage capacitor so that the storage capacitor stores a voltage; the voltage written by the data signal line for the second time corresponds to the voltage written by the data signal line for the first time and is dynamically adjusted following the voltage written by the data signal line for the first time, and the voltage written by the data signal line for the second time can maintain the voltage of the storage capacitor to maintain the potential of the driving transistor.

[0005] In the pixel driving circuit of the present invention, the data signal line can be written with voltage twice, wherein the voltage written for the second time to the data signal line corresponds to the voltage written for the first time to the data signal line and is dynamically adjusted following the voltage written for the first time to the data signal line. In this way, the voltage of the storage capacitor is maintained by the secondary writing method to maintain the potential of the driving transistor, thereby avoiding changes in the current flowing through the driving transistor, and further avoiding the problem of flickering of the light-emitting unit or insufficient light brightness.

[0006] In some embodiments, the pixel driving circuit includes a switching transistor, which is used to control the connection or disconnection of the data signal line with the storage capacitor; the voltage written to the data signal line for the second time can act on the switching transistor to maintain the voltage of the storage capacitor.

[0007] In this way, the voltage written into the data signal line for the second time acts on the switching transistor, so that the voltage of the storage capacitor can be maintained to maintain the potential of the gate of the driving transistor, so that the potential of the gate of the driving transistor can be maintained during the light-emitting stage of the pixel unit, thereby avoiding changes in the current flowing through the driving transistor, so that the light-emitting unit emits light stably.

[0008] In some embodiments, the data signal line is connected to the drain of the switch transistor, and the storage capacitor is connected to the source of the switch transistor. The voltage of the storage capacitor can act on the source of the switch transistor, and the voltage written by the data signal line for the second time can act on the drain of the switch transistor. The voltage between the drain of the switch transistor and the source of the switch transistor is a preset voltage to maintain the voltage of the storage capacitor.

[0009] In this way, the voltage written by the data signal line for the second time acts on the drain of the switching transistor, so that the voltage between the drain of the switching transistor and the source of the switching transistor is the preset voltage, and the leakage current of the switching transistor is modulated to the minimum, so that the voltage of the storage capacitor can be maintained to maintain the potential of the gate of the driving transistor, so that the potential of the gate of the driving transistor can be maintained during the light-emitting stage of the pixel unit, thereby avoiding changes in the current flowing through the driving transistor, so that the light-emitting unit emits light stably. By controlling the leakage current, higher-precision modulation of the analog circuit part can be achieved.

[0010] In some embodiments, a voltage written to the data signal line for the first time is different from a voltage written to the data signal line for the second time.

[0011] In this way, the voltage between the drain of the switch transistor and the source of the switch transistor can be made to be a preset voltage, and the leakage current of the switch transistor is modulated to a minimum.

[0012] In some embodiments, the pixel driving circuit further includes an auxiliary capacitor, and the data signal line is respectively connected to the drain of the switch transistor and the auxiliary capacitor. The voltage written by the data signal line for the second time can act on the auxiliary capacitor, and the voltage of the auxiliary capacitor can act on the drain of the switch transistor. The voltage between the drain of the switch transistor and the source of the switch transistor is a preset voltage to maintain the voltage of the storage capacitor.

[0013] In this way, by adding an auxiliary capacitor, a new circuit structure is formed. The auxiliary capacitor can be used to store the voltage written for the second time on the data signal line. The voltage of the auxiliary capacitor can act on the drain of the switching transistor. In the light-emitting stage of the pixel unit, the voltage between the drain of the switching transistor and the source of the switching transistor is a preset voltage, and the leakage current of the switching transistor is modulated to the minimum. Therefore, the voltage of the storage capacitor can be maintained to maintain the potential of the gate of the driving transistor.

[0014] In some embodiments, one end of the auxiliary capacitor is connected to the data signal line, and the other end of the auxiliary capacitor is connected to a preset potential. During the operation of the pixel driving circuit, the preset potential remains unchanged.

[0015] In this way, during the operation of the pixel driving circuit, the preset potential remains unchanged, which can avoid the discharge of the auxiliary capacitor, so that the voltage stored in the auxiliary capacitor is maintained at the voltage written for the second time on the data signal line, ensuring that the voltage between the drain of the switching transistor and the source of the switching transistor is the preset voltage, so that the leakage current of the switching transistor is modulated to the minimum.

[0016] In some embodiments, the pixel driving circuit also includes an auxiliary transistor, and the data signal line is respectively connected to the drain of the switching transistor and the auxiliary capacitor through the auxiliary transistor, and the auxiliary transistor is used to control the connection or disconnection of the data signal line with the drain of the switching transistor and the auxiliary capacitor.

[0017] In this way, the data signal line can be connected or disconnected with the auxiliary capacitor by controlling the auxiliary transistor, so that the voltage written into the data signal line for the second time is written into the auxiliary capacitor.

[0018] In some embodiments, the pixel driving circuit further includes a switch signal line and an auxiliary signal line. The switch signal line is connected to the gate of the switch transistor to control the switch transistor to be turned on or off. The auxiliary signal line is connected to the gate of the auxiliary transistor to control the auxiliary transistor to be turned on or off.

[0019] In this way, the switch transistor can be controlled to be turned on or off through the switch signal line, and the auxiliary transistor can be controlled to be turned on or off through the auxiliary signal line, so that the voltage can be accurately written into the data signal line.

[0020] In some embodiments, when the switching transistor is in the on state and the auxiliary transistor is in the on state, the data signal line writes a voltage for the first time; when the switching transistor is in the off state and the auxiliary transistor is in the on state, the data signal line writes a voltage for the second time; when the switching transistor is in the off state and the auxiliary transistor is in the off state, the driving transistor drives the light-emitting unit to emit light.

[0021] In this way, the voltage can be accurately written into the data signal line, so that the driving transistor drives the light-emitting unit to emit light stably.

[0022] In some embodiments, during the process of writing a voltage to the data signal line for the first time, the auxiliary transistor is turned on earlier than the switch transistor.

[0023] In this way, it can be ensured that the voltage written into the data signal line for the first time can fully pass through the auxiliary transistor and then be written into the storage capacitor through the switch transistor.

[0024] In some embodiments, after the switch transistor is switched from an on state to an off state, the data signal line changes from a first write voltage to a second write voltage.

[0025] In this way, it can be ensured that the voltage written into the storage capacitor is maintained as the voltage written into the data signal line for the first time, and it can be ensured that the voltage written into the storage capacitor will not change and will not become the voltage written into the data signal line for the second time.

[0026] In some embodiments, the pixel driving circuit includes a plurality of pixel units, and the pixel units are arranged in an array. The pixel driving circuit includes a plurality of data signal lines corresponding to the plurality of columns of pixel units, and the plurality of data signal lines are independent of each other. Each pixel unit in each row of the pixel units can independently write a corresponding voltage through the data signal line to control the luminous brightness of the light-emitting unit.

[0027] In this way, the corresponding voltage can be written in a row writing manner, so that the light-emitting unit of each pixel unit emits light according to the required light-emitting brightness.

[0028] In some embodiments, the pixel driving circuit further includes a switch signal line, wherein the switch signal line is connected to a gate of the switch transistor to control the switch transistor to be turned on or off.

[0029] In this way, the switching transistor can be controlled to be turned on or off by the switching signal line so that the data signal line can accurately write the voltage. In this case, no auxiliary capacitor or auxiliary transistor is required to make the voltage between the drain of the switching transistor and the source of the switching transistor a preset voltage.

[0030] In some embodiments, when the switch transistor is in the on state and the light-emitting unit is not emitting light, the data signal line is written with voltage for the first time; when the switch transistor is in the off state and the light-emitting unit is emitting light, the data signal line is written with voltage for the second time.

[0031] In this way, the voltage written into the data signal line for the first time can be accurately stored in the storage capacitor, and the voltage written into the data signal line for the second time can maintain the Vds voltage of the switching transistor.

[0032] In some embodiments, when the light-emitting unit does not emit light, a voltage is written to the data signal line for the first time; and when the light-emitting unit emits light, a voltage is written to the data signal line for the second time.

[0033] In this way, the voltage written into the data signal line for the first time can be accurately stored in the storage capacitor, and the voltage written into the data signal line for the second time can maintain the voltage of the storage capacitor to keep the potential of the gate of the driving transistor.

[0034] In some embodiments, the pixel driving circuit includes a switch transistor, the data signal line is connected to the drain of the switch transistor, the storage capacitor is connected to the source of the switch transistor, and the switch transistor is used to control the connection or disconnection between the data signal line and the storage capacitor. The voltage written by the data signal line for the second time can act on the drain of the switch transistor, and the voltage between the drain of the switch transistor and the source of the switch transistor is a preset voltage to maintain the voltage of the storage capacitor.

[0035] In this way, the voltage written by the data signal line for the second time acts on the drain of the switching transistor, so that the voltage between the drain of the switching transistor and the source of the switching transistor is the preset voltage, and the leakage current of the switching transistor is modulated to the minimum, so that the voltage of the storage capacitor can be maintained to maintain the potential of the gate of the driving transistor, so that the potential of the gate of the driving transistor can be maintained during the light-emitting stage of the pixel unit, thereby avoiding changes in the current flowing through the driving transistor, so that the light-emitting unit emits light stably. By controlling the leakage current, higher-precision modulation of the analog circuit part can be achieved.

[0036] In some embodiments, when the switch transistor is in the on state and the light-emitting unit is not emitting light, the data signal line is written with voltage for the first time; when the switch transistor is in the off state and the light-emitting unit is emitting light, the data signal line is written with voltage for the second time.

[0037] In this way, the voltage written into the data signal line for the first time can be accurately stored in the storage capacitor, and the voltage written into the data signal line for the second time can maintain the Vds voltage of the switching transistor.

[0038] In some implementations, the voltage written into the data signal line for the second time can act on the storage capacitor to maintain the voltage of the storage capacitor and keep the potential of the gate of the driving transistor.

[0039] In this way, the voltage written to the data signal line for the second time can maintain the voltage of the storage capacitor to maintain the potential of the gate of the driving transistor. Without threshold compensation, the pixel driving circuit does not need a switching transistor, which can reduce the number of transistors, compress the layout area, and improve the pixel density (PPI).

[0040] In some embodiments, the voltage written to the data signal line for the first time is the same as the voltage written to the data signal line for the second time.

[0041] In this way, when the voltage written into the data signal line for the second time directly acts on the storage capacitor, the voltage stored in the storage capacitor can be prevented from changing.

[0042] In some embodiments, the pixel driving circuit includes a plurality of pixel units arranged in an array, the pixel driving circuit includes a plurality of data signal lines corresponding to the plurality of columns of pixel units, the plurality of data signal lines are interconnected, and all the pixel units can write the same voltage together through the data signal lines.

[0043] In this way, the data signal lines can be globally written so that the pixel driving circuit can operate normally.

[0044] In some embodiments, the pixel unit includes a light-emitting control transistor, which is used to control the light-emitting unit to emit light or not, and the light-emitting control transistors of all the pixel units are independent of each other. The pixel unit can control the light-emitting brightness of the light-emitting unit by the duty cycle of the conduction signal of the corresponding light-emitting control transistor.

[0045] In this way, when the light emitting brightness of the light emitting units controlled by analog modulation is the same, the light emitting brightness of the light emitting units is controlled by digital modulation.

[0046] An embodiment of the present invention provides a display panel, comprising a control unit and a pixel driving circuit according to any one of the above embodiments, wherein the control unit is used to control the pixel driving circuit.

[0047] In the display panel of the present invention, the data signal line can be written with voltage twice, wherein the voltage written for the second time to the data signal line corresponds to the voltage written for the first time to the data signal line and is dynamically adjusted following the voltage written for the first time to the data signal line. In this way, the voltage of the storage capacitor is maintained by secondary writing to maintain the potential of the driving transistor, thereby avoiding changes in the current flowing through the driving transistor, and further avoiding the problem of flickering of the light-emitting unit or insufficient light brightness.

[0048] An embodiment of the present invention provides a display device, which includes a housing and the above-mentioned display panel, wherein the display panel is disposed in the housing.

[0049] In the display device of the present invention, the data signal line can write voltage twice, wherein the voltage written to the data signal line for the second time corresponds to the voltage written to the data signal line for the first time and is dynamically adjusted following the voltage written to the data signal line for the first time. In this way, the voltage of the storage capacitor is maintained by the secondary writing method to maintain the potential of the driving transistor, thereby avoiding changes in the current flowing through the driving transistor, and further avoiding the problem of flickering of the light-emitting unit or insufficient light brightness.

[0050] An embodiment of the present invention provides a control method for a pixel driving circuit, wherein the pixel driving circuit includes a pixel unit and a data signal line, wherein the pixel unit includes a light-emitting unit, a driving transistor and a storage capacitor; the storage capacitor is used to store a voltage, and the voltage stored in the storage capacitor can act on the driving transistor to drive the light-emitting unit; the control method includes: controlling the data signal line to write a voltage twice, the voltage written by the data signal line for the first time acts on the storage capacitor so that the storage capacitor stores a voltage; the voltage written by the data signal line for the second time corresponds to the voltage written by the data signal line for the first time and is dynamically adjusted following the voltage written by the data signal line for the first time, and the voltage written by the data signal line for the second time can maintain the voltage of the storage capacitor to maintain the potential of the driving transistor.

[0051] In the control method of the pixel driving circuit of the present invention, the data signal line can write voltage twice, wherein the voltage written to the data signal line for the second time corresponds to the voltage written to the data signal line for the first time and is dynamically adjusted following the voltage written to the data signal line for the first time. In this way, the voltage of the storage capacitor is maintained by the secondary writing method to maintain the potential of the driving transistor, thereby avoiding changes in the current flowing through the driving transistor, and further avoiding the problem of flickering of the light-emitting unit or insufficient light brightness.

[0052] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0054] Figure 1 is a schematic diagram of a pixel driving circuit in the related art;

[0055] Figure 2 It is a schematic diagram of the working timing of a pixel driving circuit in the related art;

[0056] Figure 3 is a schematic diagram of a pixel driving circuit according to some embodiments of the present invention;

[0057] Figure 4 is a schematic diagram of a pixel unit according to some embodiments of the present invention;

[0058] Figure 5 is a schematic diagram of the relationship between the voltage and current of a data signal line in some embodiments of the present invention;

[0059] Figure 6 is a schematic diagram of the working timing of a pixel driving circuit in some embodiments of the present invention;

[0060] Figure 7 is a schematic diagram of a pixel driving circuit according to some embodiments of the present invention;

[0061] Figure 8 is a schematic diagram of the working timing of a pixel driving circuit in some embodiments of the present invention;

[0062] Fig. 9 is a schematic diagram of a pixel driving circuit according to some embodiments of the present invention;

[0063] Fig.10 is a schematic diagram of the working timing of a pixel driving circuit in some embodiments of the present invention;

[0064] Fig.11 is a schematic diagram of a pixel driving circuit according to some embodiments of the present invention;

[0065] Fig.12 is a schematic diagram of a display device according to some embodiments of the present invention. DETAILED DESCRIPTION

[0066] The embodiments of the present invention are described in detail below, and the embodiments of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0067] The pixel driving circuit of Micro LED is a digital-analog hybrid driving circuit, which is relatively complex. Among them, the analog driving part has a complex structure and high performance requirements.

[0068] The working principle of the analog modulation end of the Micro LED pixel driving circuit is as follows: during the data voltage writing phase, the switching transistor is turned on to store the data voltage in the capacitor, and during the light-emitting phase, the switching transistor is turned off to control the gate of the driving transistor through the discharge of the data voltage stored in the capacitor.

[0069] Specifically, see Figure 1 and Figure 2 In the related art, in the T1 phase, SC is low level, P i The switch transistor is turned on, EM is high, P j Turn off, Data voltage through P i The data is stored in capacitor C1, and the LED does not emit light. In the T2 phase, SC is turned off, and after EM is turned on, the Data voltage written in the T1 phase controls the PD (driving transistor) to control the current I flowing through the PD. D , control the brightness and level of LED light (these two stages are analog control working principles, and digital control mainly modulates the duty cycle of the EM tube during the conduction stage).

[0070] Due to the small size of silicon-based Micro LEDs, the process precision is not enough for a large number of Fabs. In addition, due to the diffusion current of the MOS device (such as the switching transistor), there is still leakage current (Leakage Current) when the MOS is turned off. The data voltage in the capacitor may still leak current from the switching transistor, causing the potential of the gate of the driving transistor to decay. When the potential of the gate of the driving transistor decays, the current flowing through the driving transistor will change synchronously, and the final optical display will show flickering and insufficient brightness. For example, please refer to Figure 1 , when P i When there is leakage at the S end of the tube, the Data voltage stored in C1 cannot be maintained during the light-emitting phase, thus affecting I D , thus affecting the display effect.

[0071] See also Figure 3 and Figure 4The embodiment of the present invention provides a pixel driving circuit 10, which includes a pixel unit 11 and a data signal line 12. The pixel unit 11 includes a light-emitting unit 112, a driving transistor 114 and a storage capacitor 116; the storage capacitor 116 is used to store a voltage, and the voltage stored in the storage capacitor 116 can act on the driving transistor 114 to drive the light-emitting unit 112. The data signal line 12 can write a voltage twice, and the voltage written by the data signal line 12 for the first time acts on the storage capacitor 116, so that the storage capacitor 116 stores a voltage; the voltage written by the data signal line 12 for the second time corresponds to the voltage written by the data signal line 12 for the first time and is dynamically adjusted following the voltage written by the data signal line 12 for the first time, and the voltage written by the data signal line 12 for the second time can maintain the voltage of the storage capacitor 116 to maintain the potential of the driving transistor 114.

[0072] In the pixel driving circuit 10 of the present invention, the data signal line 12 can write voltage twice, wherein the voltage written to the data signal line 12 for the second time corresponds to the voltage written to the data signal line 12 for the first time and is dynamically adjusted following the voltage written to the data signal line 12 for the first time. In this way, the voltage of the storage capacitor 116 is maintained by secondary writing to maintain the potential of the driving transistor 114, thereby avoiding changes in the current flowing through the driving transistor 114, and further avoiding the problem of flickering or insufficient brightness of the light-emitting unit 112.

[0073] The data signal line 12 can be written with voltage twice, which can be specifically understood as: in the process of the light-emitting unit 112 in a pixel unit 11 working according to a frame of display picture, the data signal line 12 can be written with voltage twice. Among them, the voltage (i.e., data voltage) written by the data signal line 12 for the first time can be written into the storage capacitor 116, and the voltage stored in the storage capacitor 116 can act on the driving transistor 114. In the present invention, the voltage stored in the storage capacitor 116 acts on the gate of the driving transistor 114 as an example for explanation, and the light-emitting unit 112 can emit light according to the voltage stored in the storage capacitor 116. After the voltage is written for the first time, the data signal line 12 is written with voltage for the second time, and the voltage written by the data signal line 12 for the second time can maintain the voltage of the storage capacitor 116 to maintain the potential of the driving transistor 114 (for example, maintain the voltage of the gate of the driving transistor 114), thereby avoiding the change of the current flowing through the driving transistor 114, so that the light-emitting unit 112 emits light stably.

[0074] The voltage written to the data signal line 12 for the first time can be written into the storage capacitor 116, and the light-emitting unit 112 can emit light according to the voltage stored in the storage capacitor 116. When displaying different frames or displaying the same frame at different brightness, the voltage written to the data signal line 12 for the first time may be different. Therefore, the voltage written to the data signal line 12 for the second time can correspond to the voltage written to the data signal line 12 for the first time and dynamically adjust following the voltage written to the data signal line 12 for the first time. In this way, it can be ensured that the voltage of the storage capacitor 116 can be maintained during the light-emitting stage of the pixel unit 11 to maintain the potential of the gate of the driving transistor 114, thereby avoiding changes in the current flowing through the driving transistor 114, and further avoiding the problem of flickering or insufficient light brightness of the light-emitting unit 112.

[0075] The pixel driving circuit 10 can be applied to silicon-based Micro LED display devices, OLED display devices, LCD display devices, etc., without specific limitation herein.

[0076] See also Figure 3 In some embodiments, the pixel driving circuit 10 includes a switch transistor 13, which is used to control the connection or disconnection between the data signal line 12 and the storage capacitor 116. The voltage written to the data signal line 12 for the second time can act on the switch transistor 13 to maintain the voltage of the storage capacitor 116.

[0077] In this way, the voltage written into the data signal line 12 for the second time acts on the switching transistor 13, so that the voltage of the storage capacitor 116 can be maintained to maintain the potential of the gate of the driving transistor 114, so that the potential of the gate of the driving transistor 114 can be maintained during the light-emitting stage of the pixel unit 11, thereby avoiding changes in the current flowing through the driving transistor 114, so that the light-emitting unit 112 emits light stably.

[0078] See also Figure 3 In some embodiments, the data signal line 12 is connected to the drain of the switch transistor 13, and the storage capacitor 116 is connected to the source of the switch transistor 13. The voltage of the storage capacitor 116 can act on the source of the switch transistor 13, and the voltage written by the data signal line 12 for the second time can act on the drain of the switch transistor 13. The voltage between the drain of the switch transistor 13 and the source of the switch transistor 13 is a preset voltage to maintain the voltage of the storage capacitor 116.

[0079] In this way, the voltage written by the data signal line 12 for the second time acts on the drain of the switch transistor 13, so that the voltage between the drain of the switch transistor 13 and the source of the switch transistor 13 is the preset voltage, and the leakage current of the switch transistor 13 is modulated to the minimum, so that the voltage of the storage capacitor 116 can be maintained to maintain the potential of the gate of the driving transistor 114, so that the potential of the gate of the driving transistor 114 can be maintained during the light-emitting stage of the pixel unit 11, thereby avoiding the current flowing through the driving transistor 114 from changing, so that the light-emitting unit 112 emits light stably. By controlling the leakage current, higher-precision modulation of the analog circuit part can be achieved.

[0080] Specifically, through simulation verification, control Figure 1 Medium i The Vds voltage of the tube can most effectively control the leakage of its S terminal and can control the leakage current below 2fA, so that the storage voltage stored in C1 can stably drive PD during the light-emitting stage without a large amount of leakage, thereby improving the accuracy of the control current. In addition, through simulation verification, the leakage current I off With switch tube P i Table 1 shows the current and voltage data of each node at 0.4ms and 2ms of the circuit lighting stage. D From the distribution, we can see that with the change of Vds, we can find a minimum I off , so that V Gate The voltage change is minimal, resulting in the controlled driver transistor output current I D The change is minimal (for example, the voltage V written on the data signal line in Table 1 DataPark When V is 1.8V, Gate The voltage change is minimal, and the output current I D Therefore, the voltage of the storage capacitor 116 can act on the source of the switch transistor 13, the voltage written by the data signal line 12 for the second time can act on the drain of the switch transistor 13, the voltage between the drain of the switch transistor 13 and the source of the switch transistor 13 is a preset voltage, and the leakage current of the switch transistor 13 is modulated to a minimum to maintain the voltage of the storage capacitor 116, so that the potential of the gate of the driving transistor 114 can be maintained during the light emitting stage of the pixel unit 11.

[0081]

[0082]

[0083] Table 1

[0084] In other embodiments, the switching transistor 13 may also be connected to the data signal line 12 and the storage capacitor 16 through other connection methods, for example, the data signal line 12 is connected to the source of the switching transistor 13, and the storage capacitor 116 is connected to the drain of the switching transistor 13, so that the voltage between the drain of the switching transistor 13 and the source of the switching transistor 13 is a preset voltage, which is not specifically limited here.

[0085] See also Figure 5 In some embodiments, the voltage written to the data signal line 12 for the first time is different from the voltage written to the data signal line 12 for the second time.

[0086] In this way, the voltage between the drain of the switch transistor 13 and the source of the switch transistor 13 can be made to be a preset voltage, and the leakage current of the switch transistor 13 is modulated to be minimum.

[0087] Specifically, Figure 5 In the figure, the horizontal axis is the current in uA, and the vertical axis is the voltage in V. Figure 5 As shown in Table 2, in different frames, when the voltage (data voltage Data) written for the first time is different, there will be a voltage that dynamically corresponds to the voltage written for the first time, and this voltage can be used as the voltage (Data Park) written for the second time.

[0088]

[0089]

[0090] Table 2

[0091] See also Figure 3 In some embodiments, the pixel driving circuit 10 further includes an auxiliary capacitor 14, and the data signal line 12 is respectively connected to the drain of the switch transistor 13 and the auxiliary capacitor 14. The voltage written by the data signal line 12 for the second time can act on the auxiliary capacitor 14, and the voltage of the auxiliary capacitor 14 can act on the drain of the switch transistor 13. The voltage between the drain of the switch transistor 13 and the source of the switch transistor 13 is a preset voltage to maintain the voltage of the storage capacitor 116.

[0092] In this way, by adding an auxiliary capacitor 14, a new circuit structure is formed. The auxiliary capacitor 14 can be used to store the voltage written for the second time to the data signal line 12. The voltage of the auxiliary capacitor 14 can act on the drain of the switching transistor 13. In the light-emitting stage of the pixel unit 11, the voltage between the drain of the switching transistor 13 and the source of the switching transistor 13 is a preset voltage, and the leakage current of the switching transistor 13 is modulated to the minimum. Therefore, the voltage of the storage capacitor 116 can be maintained to maintain the potential of the gate of the driving transistor 114.

[0093] See also Figure 3 While keeping the switch transistor 13 of the pixel driving circuit 10 and other internal structures of the pixel unit 11 unchanged, an auxiliary capacitor 14 is added to each pixel unit 11, and the voltage written for the second time to the data signal line 12 can be written into the auxiliary capacitor 14.

[0094] See also Figure 3 In some embodiments, one end of the auxiliary capacitor 14 is connected to the data signal line 12, and the other end of the auxiliary capacitor 14 is connected to a preset potential. During the operation of the pixel driving circuit 10, the preset potential remains unchanged.

[0095] In this way, during the operation of the pixel driving circuit 10, the preset potential remains unchanged, which can prevent the auxiliary capacitor 14 from discharging, so that the voltage stored in the auxiliary capacitor 14 is maintained at the voltage written for the second time to the data signal line 12, ensuring that the voltage between the drain of the switching transistor 13 and the source of the switching transistor 13 is the preset voltage, so that the leakage current of the switching transistor 13 is modulated to the minimum.

[0096] The other end of the auxiliary capacitor 14 is connected to a preset potential, which may be grounded or connected to a fixed potential, which is not specifically limited here.

[0097] See also Figure 3 In some embodiments, the pixel driving circuit 10 also includes an auxiliary transistor 15, and the data signal line 12 is respectively connected to the drain of the switching transistor 13 and the auxiliary capacitor 14 through the auxiliary transistor 15, and the auxiliary transistor 15 is used to control the connection or disconnection of the data signal line 12 with the drain of the switching transistor 13 and the auxiliary capacitor 14.

[0098] In this way, the data signal line 12 and the auxiliary capacitor 14 can be connected or disconnected by the auxiliary transistor 15 , so that the voltage written for the second time on the data signal line 12 is written into the auxiliary capacitor 14 .

[0099] Specifically, see Figure 3 , while keeping the switch transistor 13 of the pixel driving circuit 10 and other internal structures of the pixel unit 11 unchanged, an auxiliary capacitor 14 and an auxiliary transistor 15 are added to each pixel unit 11 to form a 1T1C circuit structure, and the data signal line 12 can write a voltage to the auxiliary capacitor 14 through the auxiliary transistor 15. Through the 1T1C circuit structure, the voltage written by the data signal line 12 for the second time acts on the drain of the switch transistor 13, so that the voltage between the drain of the switch transistor 13 and the source of the switch transistor 13 is a preset voltage, and the leakage current of the switch transistor 13 is modulated to a minimum.

[0100] See also Figure 3In some embodiments, the pixel driving circuit 10 further includes a switch signal line 16 and an auxiliary signal line 17. The switch signal line 16 is connected to the gate of the switch transistor 13 to control the switch transistor 13 to be turned on or off. The auxiliary signal line 17 is connected to the gate of the auxiliary transistor 15 to control the auxiliary transistor 15 to be turned on or off.

[0101] In this way, the switch transistor 13 can be turned on or off by the switch signal line 16 , and the auxiliary transistor 15 can be turned on or off by the auxiliary signal line 17 , so that the voltage can be accurately written into the data signal line 12 .

[0102] The switch signal line 16 and the auxiliary signal line 17 can be arranged in a row distribution manner, that is, the pixel units 11 of each row correspond to the same switch signal line 16 and the same auxiliary signal line 17, which is not specifically limited here.

[0103] See also Figure 6 In some embodiments, when the switch transistor 13 is in the on state and the auxiliary transistor 15 is in the on state, the data signal line 12 is written with voltage for the first time; when the switch transistor 13 is in the off state and the auxiliary transistor 15 is in the on state, the data signal line 12 is written with voltage for the second time; when the switch transistor 13 is in the off state and the auxiliary transistor 15 is in the off state, the driving transistor 114 drives the light-emitting unit 112 to emit light.

[0104] In this way, the voltage can be accurately written into the data signal line 12 so that the driving transistor 114 drives the light emitting unit 112 to emit light stably.

[0105] Specifically, Figure 6 for Figure 3 Schematic diagram of the working timing of the pixel driving circuit. In the T1 stage, the switch signal line 16 (RS) and the auxiliary signal line 17 (PS) are both low level, the switch transistor 13 (P1) and the auxiliary transistor 15 (P2) are turned on, and the voltage (Data) written for the first time by the data signal line 12 (DATA) is written into the storage capacitor 116. The voltage written for the first time by the data signal line 12 (DATA) also pre-charges the auxiliary capacitor 14 (C2), V C2 =VData. In the T2 phase, the switch signal line 16 (RS) is at a high level, the switch transistor 13 (P1) is turned off, the auxiliary signal line 17 (PS) is at a low level, the auxiliary transistor 15 (P2) is turned on, and the voltage (Data Park) written for the second time on the data signal line 12 (DATA) matches the voltage (Data) written in the T1 phase. The voltage (Data Park) written for the second time on the data signal line 12 (DATA) is written into the auxiliary capacitor 14 (C2), VC2 =V Data_Park In the T3 phase, the pixel driving circuit 10 can perform other functional timings such as compensation. If not, the switch signal line 16 (RS) and the auxiliary signal line 17 (PS) are both high level, the switch transistor 13 (P1) and the auxiliary transistor 15 (P2) are turned off, the pixel unit 11 works normally, and the Data voltage stored in the storage capacitor 116 controls the current of the driving transistor 114. The Data Park voltage in the auxiliary capacitor 14 (C2) keeps the D terminal of the switch transistor 13 (P1) at a specific voltage, thereby maintaining the Vds voltage of the switch transistor 13 (P1), thereby controlling the leakage current of the S segment of the switch transistor 13 (P1).

[0106] See also Figure 3 and Figure 6 In some embodiments, during the process of writing a voltage to the data signal line 12 for the first time, the turn-on time of the auxiliary transistor 15 is earlier than the turn-on time of the switch transistor 13 .

[0107] In this way, it can be ensured that the voltage written into the data signal line 12 for the first time can fully pass through the auxiliary transistor 15 and then be written into the storage capacitor 116 through the switch transistor 13 .

[0108] Specifically, see Figure 6 The falling time of the auxiliary signal line 17 (PS) is earlier than that of the switch signal line 16 (RS). Thus, the turn-on time of the auxiliary transistor 15 is earlier than that of the switch transistor 13.

[0109] In other embodiments, the falling time of the auxiliary signal line 17 (PS) can be the same as the falling time of the switching signal line 16 (RS), that is, the auxiliary signal line 17 (PS) and the switching signal line 16 (RS) fall synchronously; the turn-on time of the auxiliary transistor 15 is the same as the turn-on time of the switching transistor 13, that is, the auxiliary transistor 15 and the switching transistor 13 are turned on synchronously, and no specific limitation is made here.

[0110] See also Figure 3 and Figure 6 In some embodiments, after the switch transistor 13 is switched from the on state to the off state, the data signal line 12 changes from the first write voltage to the second write voltage.

[0111] In this way, it can be ensured that the voltage written into the storage capacitor 116 is maintained as the voltage written into the data signal line 12 for the first time, and it can be ensured that the voltage written into the storage capacitor 116 will not change and will not become the voltage written into the data signal line 12 for the second time.

[0112] Specifically, see Figure 6The voltage written into the data signal line 12 must jump from the first write voltage to the second write voltage after the switch signal line 16 (RS) changes from a low level to a high level, that is, after the switch transistor 13 switches from an on state to an off state.

[0113] In other embodiments, at the moment when the switch signal line 16 (RS) changes from a low level to a high level, that is, at the moment when the switch transistor 13 switches from an on state to an off state, the voltage written into the data signal line 12 jumps from the first written voltage to the second written voltage. That is to say, the switch signal line 16 (RS) changes from a low level to a high level, the switch transistor 13 switches from an on state to an off state, and the voltage written into the data signal line 12 jumps from the first written voltage to the second written voltage, and the three are synchronized.

[0114] In some implementations, the rising time of the auxiliary signal line 17 (PS) may be later than the end time of the T2 phase, so that it can be ensured that the voltage written for the second time on the data signal line 12 can be written into the auxiliary capacitor 14 .

[0115] In other embodiments, the rising time of the auxiliary signal line 17 (PS) is the same as the end time of the T2 phase, that is, the rising time of the auxiliary signal line 17 (PS) is synchronized with the end of the T2 phase.

[0116] See also Figure 7 In some embodiments, the pixel driving circuit 10 includes a plurality of pixel units 11, and the pixel units 11 are arranged in an array. The pixel driving circuit 10 includes a plurality of data signal lines 12 corresponding to the plurality of columns of pixel units 11, and the plurality of data signal lines 12 are independent of each other. Each pixel unit 11 in each row of pixel units 11 can independently write a corresponding voltage through the data signal line 12 to control the luminous brightness of the light-emitting unit 112.

[0117] In this way, the corresponding voltage can be written in a row writing manner, so that the light emitting unit 112 of each pixel unit 11 emits light according to the required light emitting brightness.

[0118] Specifically, see Figure 7 , Figure 7 Schematic diagram of circuit connection of three rows and three columns (3*3) of pixel units 11, Figure 8 The corresponding row timing diagram is shown, in which the switch signal line 16 (RS) and the auxiliary signal line 17 (PS) both use row scanning signals and can be shared by rows. The data signal line 12 (DATA) is a column-shared signal. A larger array can be expanded in this connection mode.

[0119] Taking the row scanning writing of the data signal line 12 (DATA) as an example, Figure 8 This is a schematic diagram of the line-by-line scanning timing.

[0120] First row: When RS1 (the switch signal line of the first row) and PS1 (the auxiliary signal line of the first row) are both at low levels, it is the voltage (Data) writing stage for all columns of the first row pixel unit 11, and the voltage (Data) written for the first time by the data signal line 12 (DATA) of each column is written into the storage capacitor 116 of the corresponding pixel unit 11. After the Data of all columns of the first row is written, RS1 is at a high level, RS1 is turned off, PS1 is at a low level, and PS1 remains turned on. At this time, it is the voltage (Data Park) writing stage for all columns of the first row pixel unit 11, and the voltage (Data Park) written for the second time by the data signal line 12 (DATA) of each column is written into the corresponding auxiliary capacitor 14. In the light-emitting stage, the Data Park voltage in the auxiliary capacitor 14 keeps a specific voltage at the D end of the switch transistor 13, thereby maintaining the Vds voltage of the switch transistor 13, thereby controlling the leakage current of the S segment of the switch transistor 13.

[0121] The second row: When RS2 (the switch signal line of the second row) and PS2 (the auxiliary signal line of the second row) are both at low levels, it is the voltage (Data) writing stage for all columns of the second row pixel unit 11. It is necessary to ensure that PS1 of the first row is turned off to prevent the voltage (Data) of all columns of the second row from being written into the capacitor of the first row. The rest of the working state is the same as the mode of the first row: the voltage (Data) written for the first time by the data signal line 12 (DATA) of each column is written into the storage capacitor 116 of the corresponding pixel unit 11. After the data of all columns of the second row is written, RS2 is at a high level, RS2 is turned off, PS2 is at a low level, and PS2 remains on. At this time, it is the voltage (Data Park) writing stage for all columns of the second row pixel unit 11, and the voltage (Data Park) written for the second time by the data signal line 12 (DATA) of each column is written into the corresponding auxiliary capacitor 14.

[0122] The working method of the array with n rows and m columns is the same as that of the array with three rows and three columns mentioned above. When the array with n rows and m columns adopts row scanning, the above 3 rows can be converted into n rows.

[0123] Figure 3 The circuit shown can perform analog modulation alone (control the brightness of the light emitting unit 112 through the voltage stored in the storage capacitor 116), or can perform mixed digital-analog modulation. Figure 4The pixel unit 11 includes a light-emitting control transistor 118, which is used to control the light-emitting unit 112 to emit light or not. The light-emitting control transistors 118 of all pixel units 11 are independent of each other. The pixel unit 11 can control the light-emitting brightness of the light-emitting unit 112 through the duty cycle (digital modulation) of the conduction signal of the corresponding light-emitting control transistor 118.

[0124] Figure 3 The circuit shown can be written globally, that is, multiple data signal lines 12 can be associated with each other, all pixel units 11 can write the same voltage through the data signal line 12, all switch transistors 13 can be controlled synchronously, that is, all switch signal lines 16 can be low or high at the same time, all auxiliary transistors 15 can be controlled synchronously, all auxiliary signal lines 17 can be low or high at the same time, for each frame of the displayed picture, the voltage (Data) written by the data signal line 12 of each column for the first time is the same, and the voltage (Data Park) written by the data signal line 12 of each column for the second time is the same. In the same frame, the current passing through the driving transistor 114 of each pixel unit 11 is basically the same (the voltage written by the data signal line 12 stored in the storage capacitor 116 for the first time controls the luminous brightness of the light-emitting unit 112), and the luminous brightness of the light-emitting unit 112 can be controlled by digital modulation, that is, the luminous brightness of the light-emitting unit 112 is controlled by the duty cycle of the conduction signal of the corresponding light-emitting control transistor 118.

[0125] See also Fig. 9 In some embodiments, the pixel driving circuit 10 further includes a switch signal line 16 , and the switch signal line 16 is connected to the gate of the switch transistor 13 to control the switch transistor 13 to be turned on or off.

[0126] In this way, the switch transistor 13 can be controlled to be turned on or off by the switch signal line 16 so that the data signal line 12 can accurately write the voltage. In this case, the auxiliary capacitor 14 and the auxiliary transistor 15 are not required to make the voltage between the drain of the switch transistor 13 and the source of the switch transistor 13 a preset voltage.

[0127] Specifically, see Fig. 9 , Fig. 9The connection mode is suitable for digital-analog hybrid modulation. The circuit is not changed. The data signal line 12 is only kept at the second written voltage during the light-emitting stage. The second written voltage of the data signal line 12 can act on the drain of the switch transistor 13. In essence, the Vds of the switch transistor 13 is controlled to control the leakage current. For each frame of the displayed picture, the data signal line 12 is written globally, that is, multiple data signal lines 12 are related to each other, and all pixel units 11 can write the same voltage together through the data signal line 12. All switch transistors 13 can be controlled synchronously, that is, all switch signal lines 16 can be low or high at the same time. For each frame of the displayed picture, please refer to Fig.10 , all the switch transistors 13 are synchronously controlled, all the switch signal lines 16 can be low level or high level at the same time, the voltage written into the data signal line 12 of each column for the first time is the same, and the voltage written into the data signal line 12 of each column for the second time is the same. In the same frame, the current passing through the driving transistor 114 of each pixel unit 11 is basically the same (the voltage written into the data signal line 12 for the first time stored in the storage capacitor 116 controls the luminous brightness of the light-emitting unit 112), and at this time, the luminous brightness of the light-emitting unit 112 can be controlled by digital modulation, that is, the luminous brightness of the light-emitting unit 112 is controlled by the duty cycle of the conduction signal of the corresponding light-emitting control transistor 118.

[0128] See also Fig. 9 and Fig.10 In some embodiments, when the switch transistor 13 is in the on state and the light-emitting unit 112 is not emitting light, the data signal line 12 is written with voltage for the first time; when the switch transistor is in the off state and the light-emitting unit 112 is emitting light, the data signal line 12 is written with voltage for the second time.

[0129] In this way, the voltage written into the data signal line 12 for the first time can be accurately stored in the storage capacitor 116 , so that the voltage written into the data signal line 12 for the second time can maintain the Vds voltage of the switching transistor 13 .

[0130] Specifically, when the switch signal line 16 (RS) is at a low level, the data signal line 12 writes a voltage for the first time, and the voltage written by the data signal line 12 for the first time is written into the storage capacitor 116, and the light-emitting unit 112 does not emit light. When the switch signal line 16 (RS) is at a high level, the light-emitting unit 112 emits light, and the data signal line 12 writes a voltage for the second time, and the voltage written by the data signal line 12 for the second time acts on the drain of the switch transistor 13, and the voltage between the drain of the switch transistor 13 and the source of the switch transistor 13 is a preset voltage, and the leakage current of the switch transistor 13 is modulated to a minimum, so that the voltage of the storage capacitor 116 can be maintained to maintain the potential of the gate of the driving transistor 114, so that the potential of the gate of the driving transistor 114 can be maintained during the light-emitting stage of the pixel unit 11, thereby avoiding changes in the current flowing through the driving transistor 114, so that the light-emitting unit 112 emits light stably.

[0131] See also Figures 9 to 11 In some embodiments, when the light-emitting unit 112 does not emit light, the data signal line 12 is written with a voltage for the first time; when the light-emitting unit 112 emits light, the data signal line 12 is written with a voltage for the second time.

[0132] In this way, the voltage written to the data signal line 12 for the first time can be accurately stored in the storage capacitor 116 , and the voltage written to the data signal line 12 for the second time can maintain the voltage of the storage capacitor 116 to keep the potential of the gate of the driving transistor 114 .

[0133] See also Fig. 9 and Fig.10 In some embodiments, the pixel driving circuit 10 includes a switching transistor 13, the data signal line 12 is connected to the drain of the switching transistor 13, the storage capacitor 116 is connected to the source of the switching transistor 13, and the switching transistor 13 is used to control the connection or disconnection of the data signal line 12 and the storage capacitor 116. The voltage written to the data signal line 12 for the second time can act on the drain of the switching transistor 13, and the voltage between the drain of the switching transistor 13 and the source of the switching transistor 13 is a preset voltage to maintain the voltage of the storage capacitor 116. In some embodiments, when the switching transistor 13 is in the on state and the light-emitting unit 112 is not emitting light, the data signal line 12 is written with a voltage for the first time; when the switch tube is in the off state and the light-emitting unit 112 is emitting light, the data signal line 12 is written with a voltage for the second time. The technical solution of the pixel driving circuit 10 including the switching transistor 13 is the same as above, and will not be repeated here.

[0134] See also Fig.11 In some embodiments, the voltage written to the data signal line 12 for the second time can act on the storage capacitor 116 to maintain the voltage of the storage capacitor 116 and keep the potential of the gate of the driving transistor 114.

[0135] In this way, the voltage written into the data signal line 12 for the second time can maintain the voltage of the storage capacitor 116 to maintain the potential of the gate of the driving transistor 114. Without threshold compensation, the pixel driving circuit 10 may not need the switching transistor 13, which can reduce the number of transistors, compress the layout area, and improve the pixel density (PPI).

[0136] Specifically, when the pixel driving circuit 10 includes the switching transistor 13 , threshold compensation can be performed by the switching transistor 13 . Fig.11 This is a circuit diagram without threshold compensation. Its main change is to directly remove the switching transistor 13. The voltage written for the second time to the data signal line 12 can directly act on the gate of the driving transistor 114 and the storage capacitor 116. Since the gate of the driving transistor 114 is directly supplied by the data signal line 12 and there is no leakage current path, the voltage of the storage capacitor 116 can be maintained during the light-emitting stage and the potential of the gate of the driving transistor 114 can be maintained.

[0137] The voltage written into the data signal line 12 for the first time is written into the storage capacitor 116, and the light-emitting unit 112 does not emit light at this time. When the light-emitting unit 112 emits light, the voltage is written into the data signal line 12 for the second time, and the voltage written into the data signal line 12 for the second time acts on the storage capacitor 116 to maintain the voltage of the storage capacitor 116 and maintain the potential of the gate of the driving transistor 114.

[0138] In certain embodiments, for Fig.11 In the pixel driving circuit 10, the voltage written into the data signal line 12 for the first time is the same as the voltage written into the data signal line 12 for the second time.

[0139] In this way, when the voltage written into the data signal line 12 for the second time directly acts on the storage capacitor 116 , the voltage stored in the storage capacitor 116 can be prevented from changing.

[0140] The voltage written to the data signal line 12 for the first time is the same as the voltage written to the data signal line 12 for the second time. The voltage written to the data signal line 12 for the second time can directly act on the gate of the driving transistor 114 and the storage capacitor 116. Since the gate of the driving transistor 114 is directly supplied by the data signal line 12 and there is no leakage current path, the voltage of the storage capacitor 116 can be maintained during the light-emitting stage and the potential of the gate of the driving transistor 114 can be maintained.

[0141] See also Fig. 9 and Fig.11In some embodiments, the pixel driving circuit 10 includes a plurality of pixel units 11, and the pixel units 11 are arranged in an array. The pixel driving circuit 10 includes a plurality of data signal lines 12 corresponding to the plurality of columns of pixel units 11, and the plurality of data signal lines 12 are associated with each other, and all pixel units 11 can write the same voltage together through the data signal lines 12.

[0142] In this way, the data signal line 12 can be globally written, so that the pixel driving circuit 10 can work normally.

[0143] Specifically, one data signal line 12 corresponds to one column of pixel units 11. In the absence of auxiliary capacitors 14 to store the voltage written into the data signal line 12 for the second time, in order to enable the light-emitting units 112 of all pixel units 11 to display a frame of picture at the same time, the data signal line 12 can be written globally, that is, for each frame of picture displayed, the voltage written into the data signal line 12 of each column for the first time is the same, and the voltage written into the data signal line 12 of each column for the second time is the same. In the same frame of picture, the current passing through the driving transistor 114 of each pixel unit 11 is substantially the same.

[0144] See also Figure 4 In some embodiments, the pixel unit 11 includes a light emitting control transistor 118, which is used to control the light emitting unit 112 to emit light or not. The light emitting control transistors 118 of all pixel units 11 are independent of each other. The pixel unit 11 can control the light emitting brightness of the light emitting unit 112 through the duty cycle of the conduction signal of the corresponding light emitting control transistor 118.

[0145] In this way, when the light emitting brightness of the light emitting unit 112 controlled by analog modulation is the same, the light emitting brightness of the light emitting unit 112 is controlled by digital modulation.

[0146] Specifically, when the data signal line 12 is written globally, within the same frame, the current passing through the driving transistor 114 of each pixel unit 11 is basically the same, that is, the luminous brightness of each light-emitting unit 112 is basically the same. Therefore, in order to achieve different display effects for different pictures, the luminous brightness of the light-emitting unit 112 can be controlled by controlling the duty cycle of the conduction signal of the light-emitting control transistor 118 corresponding to each pixel unit 11.

[0147] See also Fig.12 An embodiment of the present invention provides a display panel 100 , which includes a control unit and a pixel driving circuit 10 of any one of the above embodiments, and the control unit is used to control the pixel driving circuit 10 .

[0148] In the display panel 100 of the present invention, the data signal line 12 can be written with voltage twice, wherein the voltage written for the second time to the data signal line 12 corresponds to the voltage written for the first time to the data signal line 12 and is dynamically adjusted following the voltage written for the first time to the data signal line 12. In this way, the voltage of the storage capacitor 116 is maintained by secondary writing to maintain the potential of the driving transistor 114, thereby avoiding changes in the current flowing through the driving transistor 114, and further avoiding the problem of flickering or insufficient brightness of the light-emitting unit 112.

[0149] The control unit includes, for example, a driving unit, and the control unit may be used to control the pixel driving circuit 10 , which is not specifically limited herein.

[0150] See also Fig.12 An embodiment of the present invention provides a display device 1000 , which includes a housing 200 and a display panel 100 according to any one of the above embodiments, and the display panel 100 is disposed in the housing 200 .

[0151] In the display device 1000 of the present invention, the data signal line 12 can write voltage twice, wherein the voltage written for the second time to the data signal line 12 corresponds to the voltage written for the first time to the data signal line 12 and is dynamically adjusted following the voltage written for the first time to the data signal line 12. In this way, the voltage of the storage capacitor 116 is maintained by secondary writing to maintain the potential of the driving transistor 114, thereby avoiding changes in the current flowing through the driving transistor 114, and further avoiding the problem of flickering or insufficient brightness of the light-emitting unit 112.

[0152] The embodiment of the present invention provides a control method of a pixel driving circuit 10, and the pixel driving circuit 10 can be the pixel driving circuit 10 of any of the above embodiments. The pixel driving circuit 10 includes a pixel unit 11 and a data signal line 12, and the pixel unit 11 includes a light-emitting unit 112, a driving transistor 114 and a storage capacitor 116; the storage capacitor 116 is used to store a voltage, and the voltage stored in the storage capacitor 116 can act on the driving transistor 114 to drive the light-emitting unit 112; the control method includes:

[0153] The data signal line 12 is controlled to write voltage twice. The voltage written to the data signal line 12 for the first time acts on the storage capacitor 116 so that the storage capacitor 116 stores voltage. The voltage written to the data signal line 12 for the second time corresponds to the voltage written to the data signal line 12 for the first time and is dynamically adjusted following the voltage written to the data signal line 12 for the first time. The voltage written to the data signal line 12 for the second time can maintain the voltage of the storage capacitor 116 to maintain the potential of the driving transistor 114.

[0154] In the control method of the pixel driving circuit 10 of the present invention, the data signal line 12 can write voltage twice, wherein the voltage written to the data signal line 12 for the second time corresponds to the voltage written to the data signal line 12 for the first time and is dynamically adjusted following the voltage written to the data signal line 12 for the first time. In this way, the voltage of the storage capacitor 116 is maintained by secondary writing to maintain the potential of the driving transistor 114, thereby avoiding changes in the current flowing through the driving transistor 114, and further avoiding the problem of flickering or insufficient brightness of the light-emitting unit 112.

[0155] The explanation of the pixel driving circuit 10 in the above embodiment is applicable to the control method of the pixel driving circuit 10 in the embodiment of the present invention, and will not be repeated here.

[0156] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0157] In addition, the term "connection" should be understood in a broad sense, for example, it can include fixed connection, detachable connection, or integral connection; it can include direct connection, indirect connection through an intermediate medium, and internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0158] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0159] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0160] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A pixel driving circuit, characterized in that: The pixel driving circuit comprises: A pixel unit, the pixel unit comprising a light emitting unit, a driving transistor and a storage capacitor; the storage capacitor is used to store a voltage, and the voltage stored in the storage capacitor can act on the driving transistor to drive the light emitting unit; A data signal line, wherein the data signal line can write a voltage twice, and the voltage written to the data signal line for the first time acts on the storage capacitor so that the storage capacitor stores a voltage; the voltage written to the data signal line for the second time corresponds to the voltage written to the data signal line for the first time and is dynamically adjusted following the voltage written to the data signal line for the first time, and the voltage written to the data signal line for the second time can maintain the voltage of the storage capacitor to maintain the potential of the driving transistor.

2. The pixel driving circuit according to claim 1, characterized in that: The pixel driving circuit comprises: A switch transistor, the switch transistor is used to control the data signal line to be connected or disconnected from the storage capacitor; The voltage written into the data signal line for the second time can act on the switch transistor to maintain the voltage of the storage capacitor.

3. The pixel driving circuit according to claim 2, characterized in that: The data signal line is connected to the drain of the switch transistor, and the storage capacitor is connected to the source of the switch transistor; The voltage of the storage capacitor can act on the source of the switching transistor, the voltage written by the data signal line for the second time can act on the drain of the switching transistor, and the voltage between the drain of the switching transistor and the source of the switching transistor is a preset voltage to maintain the voltage of the storage capacitor.

4. The pixel driving circuit according to claim 2, characterized in that: The voltage written into the data signal line for the first time is different from the voltage written into the data signal line for the second time.

5. The pixel driving circuit according to claim 4, characterized in that: The pixel driving circuit further includes: Auxiliary capacitor, the data signal line is connected to the drain of the switch transistor and the auxiliary capacitor respectively; The voltage written into the data signal line for the second time can act on the auxiliary capacitor, the voltage of the auxiliary capacitor can act on the drain of the switching transistor, and the voltage between the drain of the switching transistor and the source of the switching transistor is a preset voltage to maintain the voltage of the storage capacitor.

6. The pixel driving circuit according to claim 5, characterized in that: One end of the auxiliary capacitor is connected to the data signal line, and the other end of the auxiliary capacitor is connected to a preset potential. During the operation of the pixel driving circuit, the preset potential remains unchanged.

7. The pixel driving circuit according to claim 5, characterized in that: The pixel driving circuit further includes: Auxiliary transistor, the data signal line is connected to the drain of the switch transistor and the auxiliary capacitor respectively through the auxiliary transistor, and the auxiliary transistor is used to control the connection or disconnection of the data signal line with the drain of the switch transistor and the auxiliary capacitor.

8. The pixel driving circuit according to claim 7, characterized in that: The pixel driving circuit further includes: A switch signal line, the switch signal line being connected to a gate of the switch transistor to control the switch transistor to be turned on or off; An auxiliary signal line is connected to a gate of the auxiliary transistor to control the auxiliary transistor to be turned on or off.

9. The pixel driving circuit according to claim 7, characterized in that: When the switching transistor is in the on state and the auxiliary transistor is in the on state, the data signal line writes a voltage for the first time; when the switching transistor is in the off state and the auxiliary transistor is in the on state, the data signal line writes a voltage for the second time; when the switching transistor is in the off state and the auxiliary transistor is in the off state, the driving transistor drives the light-emitting unit to emit light.

10. The pixel driving circuit according to claim 9, characterized in that: During the process of writing a voltage to the data signal line for the first time, the auxiliary transistor is turned on earlier than the switch transistor.

11. The pixel driving circuit according to claim 9, characterized in that: After the switch transistor is switched from the on state to the off state, the data signal line changes from the first write voltage to the second write voltage.

12. The pixel driving circuit according to claim 5, characterized in that: The pixel driving circuit includes a plurality of pixel units, and the pixel units are arranged in an array. The pixel driving circuit includes a plurality of data signal lines corresponding to the plurality of columns of pixel units, and the plurality of data signal lines are independent of each other. Each of the pixel units in each row of the pixel units can independently write a corresponding voltage through the data signal line to control the luminous brightness of the light-emitting unit.

13. The pixel driving circuit according to claim 4, characterized in that: The pixel driving circuit further includes: A switch signal line is connected to a gate of the switch transistor to control the switch transistor to be turned on or off.

14. The pixel driving circuit according to claim 4, characterized in that: When the switch transistor is in the on state and the light-emitting unit is not emitting light, the data signal line is written with voltage for the first time; when the switch transistor is in the off state and the light-emitting unit is emitting light, the data signal line is written with voltage for the second time.

15. The pixel driving circuit according to claim 1, characterized in that: When the light-emitting unit does not emit light, a voltage is written to the data signal line for the first time; when the light-emitting unit emits light, a voltage is written to the data signal line for the second time.

16. The pixel driving circuit according to claim 15, characterized in that: The pixel driving circuit comprises: A switch transistor, wherein the data signal line is connected to a drain of the switch transistor, the storage capacitor is connected to a source of the switch transistor, and the switch transistor is used to control the connection or disconnection between the data signal line and the storage capacitor; The voltage written into the data signal line for the second time can act on the drain of the switch transistor, and the voltage between the drain of the switch transistor and the source of the switch transistor is a preset voltage to maintain the voltage of the storage capacitor.

17. The pixel driving circuit according to claim 16, characterized in that: When the switch transistor is in the on state and the light-emitting unit is not emitting light, the data signal line is written with voltage for the first time; when the switch transistor is in the off state and the light-emitting unit is emitting light, the data signal line is written with voltage for the second time.

18. The pixel driving circuit according to claim 15, characterized in that: The voltage written into the data signal line for the second time can act on the storage capacitor to maintain the voltage of the storage capacitor and keep the potential of the gate of the driving transistor.

19. The pixel driving circuit according to claim 18, characterized in that: The voltage written into the data signal line for the first time is the same as the voltage written into the data signal line for the second time.

20. The pixel driving circuit according to any one of claims 1 to 11 and 13 to 19, characterized in that: The pixel driving circuit includes a plurality of pixel units arranged in an array. The pixel driving circuit includes a plurality of data signal lines corresponding to the plurality of columns of pixel units. The plurality of data signal lines are interconnected, and all the pixel units can write the same voltage together through the data signal lines.

21. The pixel driving circuit according to claim 20, characterized in that: The pixel unit includes a light-emitting control transistor, which is used to control the light-emitting unit to emit light or not. The light-emitting control transistors of all the pixel units are independent of each other. The pixel unit can control the light-emitting brightness of the light-emitting unit through the duty cycle of the conduction signal of the corresponding light-emitting control transistor.

22. A display panel, characterized in that: The display panel comprises a control unit and a pixel driving circuit according to any one of claims 1 to 21, wherein the control unit is used to control the pixel driving circuit.

23. A display device, characterized in that: The display device includes a housing and the display panel according to claim 22, wherein the display panel is disposed in the housing.

24. A method for controlling a pixel driving circuit, characterized in that: The pixel driving circuit includes a pixel unit and a data signal line, and the pixel unit includes a light emitting unit, a driving transistor and a storage capacitor; The storage capacitor is used to store a voltage, and the voltage stored in the storage capacitor can act on the driving transistor to drive the light-emitting unit; The control method comprises: Controlling the data signal line to write a voltage twice, the voltage written into the data signal line for the first time acts on the storage capacitor, so that the storage capacitor stores a voltage; The voltage written into the data signal line for the second time corresponds to the voltage written into the data signal line for the first time and is dynamically adjusted following the voltage written into the data signal line for the first time. The voltage written into the data signal line for the second time can maintain the voltage of the storage capacitor to maintain the potential of the driving transistor.

Images