OLED pixel circuit, display panel and driving method

Abstract

The invention discloses an OLED pixel circuit, a display panel and a driving method, and the OLED pixel circuit comprises the components of a driving module of which a first path end is connected with power supply voltage and a second path end provides driving current; the driving module comprises a driving transistor, the control end of the driving transistor receives a driving signal, the first end of the driving transistor is connected with the first node, a second node is arranged between the second end of the driving transistor and the power supply voltage, a fourth node is arranged between the second end of the driving transistor and the driving current, and the second end of the driving transistor is selectively communicated to the second node and the fourth node; the compensation module is used for compensating the voltage of the first node and comprises a first capacitor and a second capacitor, the first end of the first capacitor is connected with the first node, the second end of the first capacitor is connected with the third node, the first end of the second capacitor is connected with the power supply voltage, and the second end of the second capacitor is connected with the first node; the input module is used for providing data voltage to a third node; and the light emitting diode is connected with the fourth node so as to receive the driving current.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and more specifically, to an OLED pixel circuit, a display panel and a driving method. Background Art

[0002] In the field of display technology, with the advancement of technology and the growing demand for visualization, display screens have become an indispensable part of daily life. However, in order to ensure that the display screen can work normally and with high quality, the driving circuit technology behind it is particularly critical.

[0003] OLED (Organic Light-Emitting Diode) is an emerging display device. It has broad application prospects because of its advantages such as self-luminescence, high contrast, wide color gamut, simple preparation process, low cost, low power consumption, and easy to realize flexible display.

[0004] However, the display devices currently formed by light-emitting diodes still have some problems that need to be solved, such as threshold voltage compensation of driving transistors. If corresponding compensation is not set, it will eventually cause changes in picture brightness, resulting in flickering and uneven brightness, which will affect the display effect.

[0005] Therefore, in order to meet the market's pursuit of high-quality display effects, developing a technology or method that can improve the above-mentioned problems has become an urgent need in the current field of display technology. Summary of the invention

[0006] The purpose of the present invention is to provide an OLED pixel circuit, a display panel and a driving method, aiming to improve the threshold voltage offset problem of the driving transistor and enhance the display effect.

[0007] According to one aspect of the present invention, there is provided an OLED pixel circuit, comprising: a driving module, wherein a first channel end of the driving module is connected to a power supply voltage, and a second channel end provides a driving current; the driving module comprises a driving transistor, a control end of the driving transistor receives a driving signal, a first end of the driving transistor is connected to a first node, a second end has a second node between the second end and the power supply voltage, and a fourth node between the second end and the driving current, and the second end of the driving transistor is selectively connected to the second node and the fourth node; a compensation module, for compensating the voltage of the first node, comprising a first capacitor and a second capacitor, a first end of the first capacitor is connected to the first node, and a second end is connected to a third node, a first end of the second capacitor is connected to the power supply voltage, and a second end is connected to the first node; an input module, for providing a data voltage corresponding to grayscale data to the third node; and a light emitting diode, wherein the light emitting diode is connected to the fourth node to receive the driving current.

[0008] Optionally, a reset module is further included, configured to provide a first input voltage to the third node; and provide a second input voltage to the fourth node.

[0009] Optionally, the working cycle of the OLED pixel circuit includes: a reset stage, the reset module connects the first input voltage to the third node, and connects the second input voltage to the light-emitting diode through the fourth node; the driving module provides a low level to the second node, the connection between the second node and the power supply voltage and the second end of the driving transistor is disconnected, the driving transistor is turned on, and the first node is connected to the fourth node through the driving transistor; an improvement stage, the reset module disconnects the first input voltage from the third node, and the second input voltage is connected to the light-emitting diode through the fourth node; the driving module provides a high level to the second node, the driving transistor is turned off, and the second end of the driving transistor is disconnected from the second node and the fourth node.

[0010] In the compensation stage, the reset module connects the first input voltage to the third node; the driving transistor of the driving module is turned on, and the power supply voltage is transmitted from the driving transistor to the first node through the second node; in the writing stage, the input module charges the capacitor of the compensation module in the writing stage, and adjusts the third node voltage to the data voltage, and adjusts the first node voltage to the driving voltage, and the driving module turns off the driving transistor in the writing stage, and disconnects the driving transistor from the power supply voltage and the anode of the light-emitting diode; in the light-emitting stage, the driving module connects the power supply voltage to the anode of the light-emitting diode through the second node and the fourth node in the light-emitting stage.

[0011] Optionally, the working cycle of the OLED pixel circuit also includes: a preparation stage, which is arranged between the improvement stage and the compensation stage, and the reset module disconnects the connection between the second input voltage and the fourth node during the preparation stage; and the driving module provides a high level for the second node.

[0012] In the above-mentioned OLED pixel circuit, the driving module further includes a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, wherein the first end of the first switch tube is connected to the power supply voltage, the second end of the first switch tube is connected to the second node, and the control end of the first switch tube receives a first control signal; the first end of the second switch tube is connected to the second node, the second end of the second switch tube is connected to the second end of the driving transistor, and the control end of the second switch tube is connected to the second end of the second capacitor and the first node; the first end of the third switch tube is connected to the second end of the driving transistor, the second end of the third switch tube is connected to the fourth node, and the control end of the third switch tube receives the second control signal; the first end of the fourth switch tube is connected to the second node, the second end of the fourth switch tube receives the second control signal, and the control end of the fourth switch tube receives the first control signal.

[0013] In the above-mentioned OLED pixel circuit, the input module further includes a fifth switch tube, a first end of the fifth switch tube receives the data voltage, a second end of the fifth switch tube is connected to the third node, and a control end of the fifth switch tube receives a third control signal.

[0014] Optionally, the reset module also includes a sixth switch tube and a seventh switch tube, the first end of the sixth switch tube is connected to the first input voltage, the second end of the sixth switch tube is connected to the third node, the control end of the sixth switch tube receives the fourth control signal, the first end of the seventh switch tube is connected to the second input voltage, the second end of the seventh switch tube is connected to the fourth stage and the anode of the light-emitting diode, and the control end of the seventh switch tube receives the fifth control signal.

[0015] Optionally, the driving transistor and the fifth switch transistor are N-type channel metal oxide semiconductor field effect transistors; the first to fourth switch transistors and the sixth to seventh switch transistors are P-type channel low temperature polysilicon field effect transistors.

[0016] According to another aspect of the present invention, there is also provided an electronic device, which includes the display panel as described above.

[0017] According to another aspect of the present invention, a chip is provided, which includes the pixel compensation circuit as described above.

[0018] According to another aspect of the present invention, a display panel is provided, comprising a plurality of the above-mentioned OLED pixel circuits, wherein the display panel is a display panel selected from the group consisting of a light emitting diode display panel, a mini light emitting diode display panel, a quantum dot light emitting diode display panel and an organic light emitting diode display panel.

[0019] According to another aspect of the present invention, a driving method of an OLED pixel circuit is provided, which is used to drive the above-mentioned OLED pixel circuit, and the driving method comprises: in a compensation stage, the reset module provides the first input voltage to the third node, the driving module provides the power supply voltage to the second node, the driving transistor is turned on, and the power supply voltage is connected to the first node to achieve threshold voltage compensation for the driving transistor.

[0020] Optionally, it also includes a reset stage, wherein the reset module connects the first input voltage to the third node and connects the second input voltage to the fourth node; the driving module turns on the driving transistor, connects the first node to the fourth node through the driving transistor, and provides a low level to the second node.

[0021] The OLED pixel circuit, display panel and driving method provided by the embodiments of the present invention realize threshold voltage compensation of the driving transistor by setting a compensation module. Specifically, a design of 8 transistors and 2 capacitors is adopted, and a reset voltage is provided to the third node and the fourth node in the reset stage, and a power supply voltage and a threshold compensation voltage of the driving transistor are provided to the first node in the compensation stage to realize threshold voltage compensation, thereby improving the resulting picture brightness changes, picture flickering and other phenomena; through capacitor data resetting, the short-term afterimage problem of the light-emitting diode can also be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings.

[0023] Figure 1 A schematic diagram showing an OLED pixel circuit according to an embodiment of the present invention;

[0024] Figure 2 A signal timing diagram of an OLED pixel circuit according to an embodiment of the present invention is shown;

[0025] Figure 3 A schematic diagram showing the operation of the OLED pixel circuit in the reset stage according to an embodiment of the present invention;

[0026] Figure 4 A schematic diagram showing the operation of the OLED pixel circuit in the improvement stage according to an embodiment of the present invention;

[0027] Figure 5 A schematic diagram showing the operation of the OLED pixel circuit in the preparation stage according to an embodiment of the present invention;

[0028] Figure 6 A schematic diagram showing the operation of the OLED pixel circuit in the compensation stage according to an embodiment of the present invention;

[0029] Figure 7 A schematic diagram showing the operation of the OLED pixel circuit in the writing stage according to an embodiment of the present invention;

[0030] Figure 8 A schematic diagram showing the operation of the OLED pixel circuit in the light emitting stage according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0031] The present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same elements are represented by similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale. In addition, some well-known parts may not be shown.

[0032] In this application, many specific details of the present invention are described, such as the specific structure, size, connection relationship and technology of the modules, so as to make the present invention more clearly understood. However, as can be understood by those skilled in the art, the present invention can be implemented without following these specific details.

[0033] The present invention may be embodied in various forms, some examples of which will be described below.

[0034] Figure 1 Schematic diagram of an OLED pixel circuit according to an embodiment of the present invention is shown; Figure 1 As shown, the OLED pixel circuit is used to drive the light emitting diode OLED. The OLED pixel circuit includes: a driving module 10, a compensation module 20, an input module 30 and a reset module 40.

[0035] The driving module 10 includes a driving transistor M5, a control end of the driving transistor M3 receives a driving signal T2, a first end of the driving transistor M5 is connected to a first node N1, a second end of the driving transistor M5 is connected to a second node N2 through a switch tube M3, and a second end of the driving transistor M5 is also connected to a fourth node N4 through a switch tube M7. By controlling the on and off of the switches M3 and M7, the second end of the driving transistor M5 is selectively connected to the second node N2 and the fourth node N4. The driving module 10 also includes a switch tube M1 and a switch tube M8, a first end of the switch tube M1 is connected to a power supply voltage ELVDD, a second end of the switch tube M1 is connected to a second node N2, and a control end of the switch tube M1 receives a control signal E1; a first end of the switch tube M8 is connected to a second node N2, a second end of the switch tube M8 receives a control signal E2, a control end of the switch tube M8 receives a control signal E1, a control end of the switch tube M3 is connected to the first node N1, and a control end of the switch tube M7 receives a control signal E2. The fourth node N4 is connected to the light emitting diode OLED to provide a driving current;

[0036] The compensation module 20 includes a first capacitor C1 and a second capacitor C2, wherein a first end of the first capacitor C1 is connected to a first node N1, a second end of the first capacitor C1 is connected to a third node N3, a first end of the second capacitor C2 is connected to a power supply voltage ELVDD, a second end of the second capacitor C2 is connected to the first node N1 and to a control end of the switch tube M3, and compensation of the first node N1 is achieved through the capacitors C1 and C2.

[0037] The input module 30 includes a switch tube M2, a first end of the switch tube M2 receives a data voltage vdata corresponding to grayscale data, a second end of the switch tube M2 connects the second end of the first capacitor C1 to a third node N3, and a control end of the switch tube M2 receives a control signal T4.

[0038] The reset module 40 includes a switch tube M6 and a switch tube M4, wherein a first end of the switch tube M6 receives a first input voltage vint1, a second end of the switch tube M6 and a second end of the first capacitor C1 are connected to a third node N3, for providing the first input voltage vint1 to the third node N3, and a control end of the switch tube M6 receives a control signal T3; a first end of the switch tube M4 receives a second input voltage vint2, a second end of the switch tube M4 and a positive electrode of the light-emitting diode OLED are connected to a fourth node N4, for providing the second input voltage vint2 to the light-emitting diode OLED, and a control end of the switch tube M4 receives a control signal T1.

[0039] An anode of the light emitting diode OLED is connected to the fourth node N4 , and a cathode of the light emitting diode OLED receives a common ground voltage ELVSS, which is opposite in level to the power supply voltage ELVDD.

[0040] The circuit design can effectively compensate the threshold voltage Vth of the driving transistor M5, thereby improving the phenomenon of picture brightness change, picture flickering, etc.; the OLED pixel circuit can also improve the short-term afterimage problem of the light-emitting diode OLED.

[0041] The light emitting diode OLED, for example, has a turn-on voltage, and emits light when the voltage difference between the anode and cathode of the light emitting diode OLED is greater than or equal to the turn-on voltage. In this embodiment, the light emitting diode OLED may also be a quantum dot light emitting diode (QLED).

[0042] Specifically, in this embodiment, the driving transistor M5 and the switch transistor M8 are both N-channel oxide semiconductor field effect transistors (Oxide MOS transistors), the gate of the driving transistor M5 serves as the control terminal, the drain of the driving transistor M5 serves as the first terminal, and the source of the driving transistor M5 serves as the second terminal.

[0043] The switch tubes M1, M2, M3, M4, M6, and M7 are, for example, all P-channel low-temperature polysilicon field effect transistors (LTPS MOS tubes), which, like the switch tube M8, all function as switches. The control end of these switch tubes is the gate, the first end is the source, and the second end is the drain; or the first end is the drain, and the second end is the source, which is not distinguished here.

[0044] In this embodiment, the N-type MOS transistor is turned on by a high-level signal and turned off by a low-level signal, and the P-type MOS transistor is turned off by a high-level signal and turned on by a low-level signal.

[0045] Figure 2 FIG. 1 shows a timing diagram of a portion of periodic signals of an OLED pixel circuit according to an embodiment of the present invention. Figure 2 As shown, the working cycle of the OLED pixel circuit includes five stages, namely, a reset stage, an improvement stage, a preparation stage, a compensation stage, a writing stage and a light emitting stage, corresponding to Figure 2 The S1, S2, S3, S4, S5 and S6 time periods.

[0046] The high-level signal and the low-level signal described below refer to logic signals, which are only used to more clearly explain the working process of the embodiment of the present application, and the specific voltage values ​​are not described in detail.

[0047] Figure 3 FIG. 2 is a schematic diagram showing the operation of the OLED pixel circuit in the reset stage according to an embodiment of the present invention; Figure 3 As shown, in the reset stage, the control signal E1 is at a high level, the switch tube M1 is turned off, and the switch tube M8 is turned on; the control signal E2 is at a low level, the switch tube M7 is turned on, and the low level is transmitted to the second node N2 through the switch tube M8; the control signal T1 is at a low level, the switch tube M4 is turned on, and the second input voltage vint2 is transmitted to the fourth node N4; the drive signal T2 is at a high level, the drive transistor M5 is turned on, and the second input voltage vint2 is transmitted to the first node N1; the control signal T3 is at a low level, the switch tube M6 is turned on, and the first input voltage vint1 is transmitted to the third node N3; the control signal T4 is at a high level, the switch tube M2 is turned off, and the connection between the data voltage vdata and the third node N3 is cut off.

[0048] At this stage, the voltage of each node is shown in the following table: node Voltage N1 vint2 N2 VL (low level) N3 vint1 N4 vint2

[0049] The first input voltage Vint1 is transmitted to the third node N3 through the switch tube M6, and the second input voltage vint2 is transmitted to the first node N1 through the switch tube M4, the fourth node N4, the switch tube M7 and the switch tube M5 to reset the first capacitor C1; the second input voltage vint2 is transmitted to the fourth node N4 through the switch tube M4 to reset the anode of the light emitting diode OLED; the second input voltage vint2 is transmitted to the first node N1 through the switch tube M4, the fourth node N4, the switch tube M7 and the switch tube M5 to reset the second capacitor C2; the low level of the control signal E2 is transmitted to the second node N2 through the switch tube M8, which is used to improve the short-term afterimage problem of the light emitting diode OLED.

[0050] Figure 4 FIG. 2 is a schematic diagram showing the operation of the OLED pixel circuit in the improvement stage according to an embodiment of the present invention; Figure 4 As shown, in the improvement stage, the control signal E1 is at a high level, the switch tube M1 is turned off, and the switch tube M8 is turned on; the control signal E2 is at a high level, the switch tube M7 is turned off, and the high level is transmitted to the second node N2 through the switch tube M8; the control signal T1 is at a low level, the switch tube M4 is turned on, and the second input voltage vint2 is transmitted to the fourth node N4; the control signal T2 is at a low level, and the driving transistor M5 is turned off; the control signal T3 is at a high level, and the switch tube M6 is turned off; the control signal T4 is at a high level, and the switch tube M2 is turned off.

[0051] At this stage, the voltages of each node are shown in the following table: node Voltage N1 vint2 N2 VH (high level) N3 vint1 N4 vint2

[0052] Specifically, in the improvement stage, the voltage of the first node N1 is maintained at vint2 through the first capacitor C1 and the second capacitor C2, the voltage of the second node N1 changes to a high level with the control signal E2, the voltage of the third node N3 is maintained at vint1 through the first capacitor C1, the second input voltage vint2 is transmitted to the fourth node N4 through the switch tube M4, and the voltage of the fourth node N4 is vint2. This stage can improve the short-term afterimage problem of the light-emitting diode OLED.

[0053] Figure 5 FIG. 1 is a schematic diagram showing the operation of the OLED pixel circuit in the preparation stage according to an embodiment of the present invention; Figure 5As shown, in the preparation stage, the control signal E1 is at a high level, the switch tube M1 is turned off, and the switch tube M8 is turned on; the control signal E2 is at a high level, the switch tube M7 is turned off, and the high level is transmitted to the second node N2 through the switch tube M8; the control signal T1 is at a high level, the switch tube M4 is turned off, and the fourth node N4 is disconnected from the second input voltage vint2; the control signal T2 is at a low level, and the driving transistor M5 is turned off; the control signal T3 is at a high level, and the switch tube M6 is turned off; the control signal T4 is at a high level, and the switch tube M2 is turned off.

[0054] At this stage, the voltages of each node are shown in the following table: node Voltage N1 vint2 N2 VH (high level) N3 vint1

[0055] In the preparation stage, Figure 4 On the basis of the improvement stage, by changing the control signal T1 to a high level, the switch tube M4 is turned off, and the connection between the second input voltage vint2 and the fourth node N4 and the positive electrode of the light emitting diode OLED is disconnected.

[0056] Figure 6 FIG. 2 is a schematic diagram showing the operation of the OLED pixel circuit in the compensation stage according to an embodiment of the present invention; Figure 6 As shown, in the compensation stage, the control signal E1 is at a low level, the switch tube M1 is turned on, the switch tube M8 is turned off, and the power supply voltage ELVDD is transmitted to the second node N2; the control signal E2 is at a high level, the switch tube M7 is turned off; the control signal T1 is at a high level, the switch tube M4 is turned off; the drive signal T2 is at a high level, the drive transistor M5 is turned on, and the power supply voltage ELVDD is transmitted to the first node N1; the control signal T3 is at a low level, the switch tube M6 is turned on, and the first input voltage vint1 is transmitted to the third node N3; the control signal T4 is at a high level, the switch tube M2 is turned off, and the connection between the data voltage vdata and the third node N3 is cut off.

[0057] At this stage, the voltages of each node are shown in the following table: node Voltage N1 ELVDD+Vth N2 ELVDD N3 vint1

[0058] In the compensation stage, due to the capacitance characteristics of the first capacitor C1 and the second capacitor C2 (the voltage across the capacitors will not change suddenly), the voltage of the first node N1 is coupled to ELVDD+Vth, and the switch tube M3 is turned on, wherein Vth is the threshold voltage of the driving transistor M5, and the second end of the driving transistor M5 is connected to the second node N2, and the threshold voltage compensation of the driving transistor M5 is realized in this compensation stage.

[0059] Figure 7 FIG. 2 is a schematic diagram showing the operation of the OLED pixel circuit in the writing stage according to an embodiment of the present invention; Figure 7As shown, in the writing stage, the control signal E1 is at a low level, the switch tube M1 is turned on, the switch tube M8 is turned off, and the power supply voltage ELVDD is transmitted to the second node N2 through the switch tube M1; the control signal E2 is at a high level, the switch tube M7 is turned off; the control signal T1 is at a high level, the switch tube M4 is turned off; the driving signal T2 is at a low level, the driving transistor M5 is turned off; the control signal T3 is at a high level, the switch tube M6 is turned off; the control signal T4 is at a low level, the switch tube M2 is turned on, and the data voltage vdata is transmitted to the third node N3.

[0060] At this stage, the voltages of each node are shown in the following table: node Voltage N1 ELVDD+Vth + (vdata-vint1)*[C1 / (C1+C2)] N2 ELVDD N3 vdata

[0061] In the writing stage, the data voltage vdata is transmitted to the third node N3 through the switch tube M2, and the voltage of the first node N1 is changed to ELVDD+Vth+ (vdata-vint1)*[C1 / (C1+C2)], wherein ELVDD is the supply voltage, Vth is the threshold voltage of the driving transistor M5, vdata is the data voltage corresponding to the grayscale data, vint1 is the first input voltage, C1 is the first capacitor, and C2 is the second capacitor; the switch tube M3 is turned off, the driving transistor M5 is turned off, and the data voltage vdata is written in this writing stage.

[0062] Figure 8 FIG. 1 is a schematic diagram showing the operation of the OLED pixel circuit in the light emitting stage according to an embodiment of the present invention. Figure 8 As shown, in the light-emitting stage, the control signal E1 is at a low level, the switch tube M1 is turned on, the switch tube M8 is turned off, and the power supply voltage ELVDD is transmitted to the second node N2 through the switch tube M1; the control signal E2 is at a low level, the switch tube M7 is turned on, and the second end of the driving transistor M5 is connected to the fourth node N4; the control signal T1 is at a high level, and the switch tube M4 is turned off; the driving signal T2 is at a low level, and the driving transistor M5 is turned off; the control signal T3 is at a high level, and the switch tube M6 is turned off; the control signal T4 is at a high level, and the switch tube M2 is turned off.

[0063] At this stage, the voltages of each node are shown in the following table: node Voltage N1 ELVDD+Vth + (vdata-vint1)*[C1 / (C1+C2)] N2 ELVDD

[0064] In this light-emitting stage, the switch tube M3 is turned on, the power supply voltage ELVDD is connected to the positive electrode of the light-emitting diode OLED through the switch tube M1, the opening tube M3 and the switch tube M7, the negative electrode of the light-emitting diode OLED is connected to the common ground voltage ELVSS, the voltage of the first node N1 is ELVDD+Vth+(vdata-vint1)*[C1 / (C1+C2)], and the voltage of the second node N2 is ELVDD. According to the transistor saturation current formula:

[0065] I OLED ∝(Vgs-Vth) 2

[0066] I OLED ∝[ELVDD+Vth+(vdata-vint1)*[C1 / (C1+C2)]-ELVDD-Vth] 2

[0067] I OLED =WC ox μ / 2L*{(vdata-vint1)*[C1 / (C1+C2)]} 2

[0068] Among them, I OLED represents the driving current flowing to the light emitting diode OLED, ∝ represents proportional to, Vgs represents the rated voltage difference between the gate and source of the driving transistor M5 in the OLED pixel circuit, W represents the channel width of the driving transistor M5, L represents the channel length of the driving transistor M5, C ox is the capacitance per unit area of ​​the gate oxide layer of the driving transistor M5, μ is the carrier mobility, Vth is the threshold voltage of the driving transistor M5, vdata is the data voltage, ELVDD is the power supply voltage, W and L are fixed when designing the driving transistor, C ox Depends on the thickness and material of the control end insulation layer.

[0069] The OLED pixel circuit, display panel and driving method provided by the embodiments of the present invention realize threshold voltage compensation of the driving transistor by setting a compensation module. Specifically, a design of 8 transistors and 2 capacitors is adopted, and a reset voltage is provided to the third node and the fourth node in the reset stage, and a power supply voltage and a threshold compensation voltage of the driving transistor are provided to the first node in the compensation stage to realize threshold voltage compensation, thereby improving the resulting picture brightness changes, picture flickering and other phenomena; through capacitor data resetting, the short-term afterimage problem of the light-emitting diode can also be improved.

[0070] In the above description, the technical details of the patterning and etching of each electrode are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0071] The embodiments of the present invention are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. An OLED pixel circuit, characterized in that: include: A driving module, wherein a first channel end of the driving module is connected to a power supply voltage, and a second channel end of the driving module provides a driving current; The driving module includes a driving transistor, a control end of the driving transistor receives a driving signal, a first end of the driving transistor is connected to a first node, a second end has a second node between the second end and the power supply voltage, and has a fourth node between the second end and the driving current, and the second end of the driving transistor is selectively connected to the second node and the fourth node; a compensation module, used to compensate for the first node voltage, comprising a first capacitor and a second capacitor, wherein a first end of the first capacitor is connected to the first node, and a second end is connected to a third node, and a first end of the second capacitor is connected to the supply voltage, and a second end is connected to the first node; An input module, used for providing a data voltage corresponding to grayscale data to the third node; A light emitting diode is connected to the fourth node to receive the driving current.

2. The OLED pixel circuit according to claim 1, characterized in that: It also includes a reset module, which is used to provide a first input voltage to the third node and a second input voltage to the fourth node.

3. The OLED pixel circuit according to claim 2, characterized in that: The working cycle of the OLED pixel circuit includes: In the reset stage, the reset module connects the first input voltage to the third node, and connects the second input voltage to the light-emitting diode through the fourth node; the driving module provides a low level to the second node, the connection between the second node and the power supply voltage and the second end of the driving transistor is disconnected, the driving transistor is turned on, and the first node is connected to the fourth node through the driving transistor; In the improvement stage, the reset module disconnects the first input voltage from the third node, and the second input voltage is connected to the light-emitting diode through the fourth node; the driving module provides a high level to the second node, the driving transistor is turned off, and the second end of the driving transistor is disconnected from the second node and the fourth node. In the compensation stage, the reset module connects the first input voltage to the third node; the driving transistor of the driving module is turned on, and the power supply voltage is transmitted from the driving transistor to the first node through the second node; In the writing stage, the input module charges the capacitor of the compensation module and adjusts the third node voltage to the data voltage and the first node voltage to the driving voltage. The driving module turns off the driving transistor and disconnects the driving transistor from the power supply voltage and the anode of the light-emitting diode in the writing stage. In the light emitting stage, the driving module connects the supply voltage to the anode of the light emitting diode through the second node and the fourth node.

4. The OLED pixel circuit according to claim 3, characterized in that: The working cycle of the OLED pixel circuit also includes: A preparation stage is provided between the improvement stage and the compensation stage. The reset module disconnects the connection between the second input voltage and the fourth node during the preparation stage. The driving module provides a high level for the second node.

5. The OLED pixel circuit according to claim 4, characterized in that: The driving module also includes a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, wherein the first end of the first switch tube is connected to the power supply voltage, the second end of the first switch tube is connected to the second node, and the control end of the first switch tube receives a first control signal; the first end of the second switch tube is connected to the second node, the second end of the second switch tube is connected to the second end of the driving transistor, and the control end of the second switch tube is connected to the second end of the second capacitor and the first node; the first end of the third switch tube is connected to the second end of the driving transistor, the second end of the third switch tube is connected to the fourth node, and the control end of the third switch tube receives the second control signal; the first end of the fourth switch tube is connected to the second node, the second end of the fourth switch tube receives the second control signal, and the control end of the fourth switch tube receives the first control signal.

6. The OLED pixel circuit according to claim 7, characterized in that: The input module further includes a fifth switch tube, a first end of the fifth switch tube receives the data voltage, a second end of the fifth switch tube is connected to the third node, and a control end of the fifth switch tube receives a third control signal.

7. The OLED pixel circuit according to claim 8, characterized in that: The reset module also includes a sixth switch tube and a seventh switch tube, wherein the first end of the sixth switch tube is connected to the first input voltage, the second end of the sixth switch tube is connected to the third node, the control end of the sixth switch tube receives the fourth control signal, the first end of the seventh switch tube is connected to the second input voltage, the second end of the seventh switch tube is connected to the fourth stage and the anode of the light-emitting diode, and the control end of the seventh switch tube receives the fifth control signal.

8. The OLED pixel circuit according to claim 9, characterized in that: The driving transistor and the fifth switch transistor are N-type channel metal oxide semiconductor field effect transistors; the first to fourth switch transistors and the sixth to seventh switch transistors are P-type channel low temperature polysilicon field effect transistors.

9. A display panel comprising a plurality of OLED pixel circuits according to any one of claims 1 to 8, wherein the display panel is a light emitting diode display panel, a mini light emitting diode display panel, a quantum dot light emitting diode display panel and an organic light emitting diode display panel.

10. An electronic device, characterized in that: Comprising the display panel according to claim 9.

11. A chip, characterized in that: Comprising an OLED pixel circuit according to any one of claims 1-8.

12. A driving method of an OLED pixel circuit, for driving the OLED pixel circuit according to any one of claims 2 to 8, the driving method comprising: In the compensation stage, the reset module provides the first input voltage to the third node, the driving module provides the power supply voltage to the second node, the driving transistor is turned on, and the power supply voltage is connected to the first node to achieve threshold voltage compensation for the driving transistor.

13. The driving method according to claim 12 further includes a reset stage, wherein the reset module connects the first input voltage to the third node and connects the second input voltage to the fourth node; the driving module turns on the driving transistor, connects the first node to the fourth node through the driving transistor, and provides a low level to the second node.

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