OLED pixel circuit, driving method thereof and display panel

Abstract

The application discloses an OLED pixel circuit, a driving method thereof and a display panel. The OLED pixel circuit comprises an input module, a compensation module and a light-emitting diode. The input module receives a data voltage in a writing stage. The compensation module is configured to connect a second conduction end of a driving transistor to a control end of the driving transistor and charge a third capacitor in a compensation stage, so that a node voltage is compensated to a first voltage. The driving voltage is maintained in a light-emitting stage after the compensation stage, and the driving voltage is equal to the sum of the first voltage and a second voltage. The first voltage is equal to the sum of a power supply voltage and a threshold voltage of the driving transistor. The second voltage is related to the difference between the data voltage and a reference voltage. Thus, the phenomenon of uneven brightness and picture of the OLED display is eliminated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pixels, in particular to an OLED pixel circuit, a driving method thereof and a display panel. BACKGROUND

[0002] OLED (Organic Light-Emitting Diode) is a new flat panel display device, which has a wide application prospect due to its advantages of self-emission, high contrast, wide color gamut, simple preparation process, low cost, low power consumption and easy realization of flexible display.

[0003] In the prior art, the luminous intensity of an organic light-emitting diode OLED is determined by a data voltage Vdata, a power supply voltage ELVDD and a threshold voltage Vth of a thin film transistor. Due to the factors of manufacturing process, the threshold voltage Vth of the thin film transistor manufactured on a large-area glass substrate has a distribution difference. Meanwhile, the power supply voltage ELVDD is input from outside the effective display area and is transmitted to each pixel circuit through a wire in the effective display area. However, the wire has a certain resistance, so that the power supply voltage ELVDD will generate a direct current voltage drop, commonly known as IR drop, in the transmission process. Due to the existence of the IR drop, the distribution of the power supply voltage ELVDD in the effective display area is uneven, and in combination with the distribution difference of the threshold voltage Vth of the thin film transistor, the luminous intensity of two adjacent pixels will be different even if the same data voltage Vdata is input (commonly known as mura phenomenon).

[0004] The prior art compensates the threshold voltage Vth of the organic light-emitting diode OLED to solve the above problem, but there is no corresponding measure for the uneven display caused by the direct current voltage drop IR drop of the power supply voltage. Therefore, a new OLED pixel circuit is needed to solve the above problem. SUMMARY

[0005] In view of the above problems, the present application aims to provide an OLED pixel circuit, a driving method thereof and a display panel, so as to solve the above technical defects.

[0006] According to an aspect of the present application, an OLED pixel circuit is provided, comprising:

[0007] The drive module includes a drive transistor, a control terminal of which receives a node voltage, a first conduction terminal of which receives a supply voltage, and a second conduction terminal of which provides a drive current; the input module includes a first capacitor, a first terminal of the first capacitor being connected to the second conduction terminal of the drive transistor, and a second terminal of the first capacitor receiving a reference voltage in a compensation stage and receiving a data voltage in a write stage; the compensation module is configured to compensate the node voltage, and includes a second capacitor and a third capacitor connected in series between the first conduction terminal and the control terminal of the drive transistor, and a connection node of the second capacitor and the third capacitor receiving the supply voltage; and the light-emitting diode is connected to the drive transistor to receive the drive current, wherein the compensation module is configured to: in the compensation stage, connect the second conduction terminal of the drive transistor to the control terminal of the drive transistor, and charge the third capacitor, so that the node voltage is compensated to a first voltage; and in a light-emitting stage after the compensation stage, maintain a drive voltage, the light-emitting diode generates an effective brightness corresponding to the data voltage according to the drive current in the light-emitting stage, the drive voltage is equal to a sum of the first voltage and a second voltage, the first voltage is equal to a sum of the supply voltage and a threshold voltage of the drive transistor, and the second voltage is related to a difference between the data voltage and the reference voltage.

[0008] Optionally, the working period of the OLED pixel circuit includes: the compensation stage, in which the drive module connects the first conduction terminal of the drive transistor to the supply voltage and disconnects the second conduction terminal of the drive transistor from the anode of the light-emitting diode; the light-emitting stage, in which the drive module connects the first conduction terminal of the drive transistor to the supply voltage and connects the second conduction terminal of the drive transistor to the anode of the light-emitting diode; and the write stage, which is arranged between the compensation stage and the light-emitting stage, in which the input module and the compensation module adjust the node voltage to the drive voltage, and the drive module disconnects the drive transistor from the supply voltage and the anode of the light-emitting diode in the write stage.

[0009] Optionally, the input module further comprises a first switch tube and a second switch tube, a first conduction end of the first switch tube receives a reference voltage, a first conduction end of the second switch tube receives the data voltage, a second conduction end of the first switch tube is connected with a second conduction end of the second switch tube and connected to a second end of the first capacitor, a control end voltage of the first switch tube is configured to turn on the first switch tube in the compensation phase and turn off the first switch tube in the writing phase and the light emitting phase, and a control end voltage of the second switch tube is configured to turn on the second switch tube in the writing phase and turn off the second switch tube in the compensation phase and the light emitting phase.

[0010] Optionally, the working cycle further comprises a holding phase arranged between the compensation phase and the light emitting phase, states of the input module in the holding phase and the compensation phase are consistent, the compensation module disconnects the second conduction end of the driving transistor from the control end of the driving transistor in the holding phase, and the driving module disconnects the driving transistor from the power supply voltage and the light emitting diode in the holding phase.

[0011] Optionally, the compensation module comprises: a second capacitor and a third capacitor connected in series between the first conduction end and the control end of the driving transistor, a connection node of the second capacitor and the third capacitor receives the power supply voltage; and a third switch tube, a first conduction end of the third switch tube is connected with the control end of the driving transistor, and a second conduction end of the third switch tube is connected with the second conduction end of the driving transistor, and a control end voltage of the third switch tube is configured to turn on the third switch tube in the compensation phase and the writing phase and turn off the third switch tube in the light emitting phase.

[0012] Optionally, the third switch tube is an N-type channel MOS thin film transistor.

[0013] Optionally, the working cycle further comprises a reset phase arranged before the compensation phase, and the OLED pixel circuit further comprises a reset switch tube, a control end voltage of the reset switch tube is configured to turn on the reset switch tube to reset the anode of the light emitting diode to a reset voltage in the reset phase, in the reset phase, the driving module connects the first conduction end and the second conduction end of the driving transistor to the power supply voltage and the anode voltage of the light emitting diode respectively, and a voltage between the control end and the first conduction end of the driving transistor is a difference between the reset voltage and the power supply voltage.

[0014] Optionally, the driving module comprises: a fourth switch tube connected between the power supply voltage and the first conduction end of the driving transistor, for controlling the conduction and turn-off between the first conduction end of the driving transistor and the power supply voltage; and a fifth switch tube connected between the second conduction end of the driving transistor and the anode of the light-emitting diode, for controlling the conduction and turn-off of the driving transistor and the light-emitting diode.

[0015] According to another aspect of the present application, there is provided a display panel comprising a plurality of the above OLED pixel circuits, the display panel being one 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.

[0016] According to still another aspect of the present application, there is provided a driving method of an OLED pixel circuit, comprising: in a compensation stage, connecting the second conduction end of the driving transistor to the control end of the driving transistor, and charging the third capacitor, so that the node voltage is compensated to a first voltage; in a light-emitting stage after the compensation stage, controlling the control end voltage of the driving transistor to remain a driving voltage, so that the driving transistor provides a driving current according to the driving voltage, and the light-emitting diode generates an effective brightness corresponding to the data voltage according to the driving current, wherein the driving voltage is equal to the sum of the first voltage and a second voltage, the first voltage is equal to the sum of the power supply voltage and the threshold voltage of the driving transistor, and the second voltage is related to the difference between the data voltage and the reference voltage.

[0017] In the OLED pixel circuit provided by the present application, the input module provides the data voltage to the node N5 in the T4 time period of the light-emitting period, and couples the data voltage to the N3 node through the first capacitor, so that the driving current expression of the driving transistor for the light-emitting diode does not contain the power supply voltage and the threshold voltage of the driving transistor, thus eliminating the phenomenon of OLED display brightness and picture unevenness caused by the inconsistency of Vth and the IR drop mentioned in the prior art.

[0018] In a preferred embodiment, in the T1 time period of the light-emitting period, the first switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are turned on, the reset voltage Vint resets the gate voltage of the driving transistor through the sixth switch tube, the fifth switch tube and the first switch tube, and the control end-first conduction end voltage Vgs of the driving transistor is Vint-ELVDD, so that the driving transistor M1 of all pixel circuits can be ensured to be in the same Vgs bias voltage before the data voltage is written in the current frame, and the short-term image sticking caused by the hysteresis effect of TFT can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above and other objects, features and advantages of the present application will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:

[0020] Figure 1 A circuit connection diagram of the OLED pixel circuit according to the present application is shown;

[0021] Figure 2 A signal timing diagram of the OLED pixel circuit according to the present application is shown;

[0022] Figure 3 A working schematic of the OLED pixel circuit according to the present application in a reset phase is shown;

[0023] Figure 4 A working schematic of the OLED pixel circuit according to the present application in a compensation phase is shown;

[0024] Figure 5 A working schematic of the OLED pixel circuit according to the present application in a holding phase is shown;

[0025] Figure 6 A working schematic of the OLED pixel circuit according to the present application in a writing phase is shown;

[0026] Figure 7 A working schematic of the OLED pixel circuit according to the present application in a light emitting phase is shown. DETAILED DESCRIPTION

[0027] Various embodiments of the present application will be described hereinafter with reference to the accompanying drawings. In the drawings, like reference numerals indicate like elements or modules. For the sake of clarity, each portion in the drawings is not drawn in proportion.

[0028] It should be understood that, in the following description, "circuitry" can include a single or multiple components of hardware, programmable circuitry, state machine circuitry, and / or elements storing instructions for execution by programmable circuitry. When an element or circuitry is referred to as being "connected to" another element or "connected between" two nodes, it can be directly coupled or connected to the other element or can exist between the two nodes with intervening elements, and the connection between elements can be physical, logical, or a combination thereof. In contrast, when an element is referred to as being "directly coupled to" or "directly connected to" another element, it implies that there are no intervening elements.

[0029] Meanwhile, certain terms have been used throughout this patent document. Those of ordinary skill in the art will understand that devices, mechanisms, elements and components can have various names and have various functions according to particular nomenclature or technology. Reference herein to a particular term does not necessarily preclude that equivalent terminology can be used in other contexts to describe similar devices, mechanisms, elements and components.

[0030] In addition, it should also be noted that, in this document, relational terms such as first and second and the like can merely be used to distinguish one entity or action from another, without necessarily requiring or implying that any such order existed in the past or that any such order will exist in the future.

[0031] Figure 1 A circuit connection diagram of an OLED pixel circuit according to the present application is shown;

[0032] As Figure 1 The OLED pixel circuit shown includes an input module 10, a compensation module 20, a driving module 30, a reset switch tube M7, and a light-emitting diode OLED.

[0033] The driving module 30 includes a switch tube M5, a driving transistor M1, and a switch tube M6 connected in series between a power supply end and a ground end, wherein the control end of the driving transistor M1 receives a voltage at the N1 node, the first conduction end receives a power supply voltage ELVDD, and the second conduction end provides a driving current.

[0034] The second conduction end of the driving transistor M1 in the input module 10 and the driving module 30 is connected to the N3 node for receiving a third control signal G_1 and a fifth control signal G_4, and under the control of the third control signal G_1 and the fifth control signal G_4, providing a data voltage Vdata and a reference voltage Vref to the N3 node.

[0035] The compensation module 20 is used to compensate the potential of the N1 node.

[0036] The reset switch tube M7 is connected to the N4 node with the anode of the light-emitting diode OLED, for receiving a reset control signal G_2 and resetting the anode potential of the light-emitting diode and the second conduction end potential of the driving transistor M1 under the control of the reset control signal G_2.

[0037] The light emitting diode is connected with the driving transistor M1 through the switch transistor M6 to receive a driving current, so as to obtain an effective brightness corresponding to the data voltage.

[0038] Specifically, the input module 10 includes the switch transistor M3 and the switch transistor M4 and the first capacitor C1. The switch transistor M3 receives a third control signal G_1 at the control end, receives the data voltage Vdata at the first conduction end, and is connected with the N5 node at the second conduction end. The switch transistor M4 receives a fifth control signal G_4 at the control end, receives the reference voltage Vref at the first conduction end, and is connected with the N5 node at the second conduction end. The first capacitor C1 is connected between the N5 node and the N3 node.

[0039] The control end of the driving transistor M1 is connected with the N1 node, the first conduction end is connected with the N2 node, and the second conduction end is connected with the N3 node. The driving module 30 further includes the switch transistor M5 and the switch transistor M6. The switch transistor M5, the driving transistor M1 and the switch transistor M6 are sequentially connected between the power supply end (ELVDD) and the ground end (ELVSS). The switch transistor M5 is connected between the power supply end (ELVDD) and the N2 node, and the control end receives a second control signal E_2. The switch transistor M6 is connected between the N3 node and the N4 node, and the control end receives a first control signal E_1.

[0040] The compensation module 20 is used for compensating the potential of the N1 node, and includes the second capacitor C2 and the third capacitor C3 connected in series between the N1 node and the N2 node, and the switch transistor M2 connected between the N1 node and the N3 node. The control end of the switch transistor M2 receives a fourth control signal G_3.

[0041] The anode of the organic light emitting diode OLED is connected with the N4 node, and the cathode is connected with the ground end.

[0042] The compensation module 20 charges the N1 node voltage to ELVDD+Vth_M1 through the charging of the power supply voltage ELVDD in the T2 time period, so as to complete the threshold voltage compensation of the driving transistor M1.

[0043] The N1 node voltage is compensated to a first voltage by the compensation module 20 in the compensation stage, and a driving voltage is kept in the light-emitting stage after the compensation stage, the light-emitting diode generates an effective brightness corresponding to the data voltage according to the driving current in the light-emitting stage, the driving voltage is equal to the sum of the first voltage and the second voltage, the first voltage is equal to the sum of the supply voltage ELVDD and the threshold voltage Vth of the driving transistor, and the second voltage is related to the difference between the data voltage Vdata and the reference voltage Vref. The driving voltage expression of the driving transistor M1 does not contain Vth and the supply voltage ELVDD, so that the phenomenon of uneven OLED display brightness and picture caused by inconsistent Vth and the IR drop mentioned in the prior art is eliminated.

[0044] The control end voltage of the switch tube M6 is provided by the first control signal E_1, the control end voltage of the switch tube M5 is provided by the second control signal E_2, the control end voltage of the switch tube M3 is provided by the third control signal G_1, the control end voltage of the reset switch tube M7 is provided by the reset control signal G_2, the control end voltage of the switch tube M2 is provided by the fourth control signal G_3, and the control end voltage of the switch tube M4 is provided by the fifth control signal G_4.

[0045] Figure 2 The signal timing diagram of the OLED pixel circuit according to the present application is shown.

[0046] As Figure 2 The working period of the OLED pixel circuit provided by the present application is specifically divided into five stages, which are reset stage, compensation stage, holding stage, writing stage and light-emitting stage, which correspond to T1, T2, T3, T4 and T5 time periods in the drawing respectively. The modules are analyzed in detail according to the above stages:

[0047] The driving module 30 includes: a switch tube M5 connected between the supply voltage ELVDD and the first conduction end of the driving transistor M1, for controlling the conduction and shutdown between the first conduction end of the driving transistor M1 and the supply voltage ELVDD; and a switch tube M6 connected between the second conduction end of the driving transistor M1 and the anode of the light-emitting diode, for controlling the conduction and shutdown of the driving transistor and the light-emitting diode.

[0048] The voltage of the control end of the switch tube M5 and M6 (i.e. the first control signal E_1 and the second control signal E_2) is configured to connect the first conduction end of the drive transistor M1 to the power supply voltage ELVDD in the compensation stage, and disconnect the second conduction end of the drive transistor M1 from the anode of the light-emitting diode; connect the first conduction end of the drive transistor M1 to the power supply voltage ELVDD and the second conduction end of the drive transistor M1 to the anode of the light-emitting diode in the light-emitting stage; and disconnect the drive transistor M1 from the power supply voltage ELVDD and the anode of the light-emitting diode in the writing stage.

[0049] The voltage of the control end of the switch tube M4 (corresponding to the fifth control signal G_4) in the input module 10 is configured to turn on the switch tube M4 in the compensation stage, and turn off the switch tube M4 in the writing stage and the light-emitting stage; the voltage of the control end of the switch tube M3 (corresponding to the third control signal G_1) is configured to turn on the switch tube M3 in the writing stage, and turn off the switch tube M3 in the compensation stage and the light-emitting stage, so that the second end of the first capacitor C1 receives the reference voltage Vref in the compensation stage, and receives the data voltage Vdata in the writing stage, and the second voltage is related to the difference between the data voltage Vdata and the reference voltage Vref.

[0050] The compensation module 20 includes: the second capacitor C2 and the third capacitor C3 connected in series between the first conduction end and the control end of the drive transistor M1, and the connection node of the second capacitor C2 and the third capacitor C3 receiving the power supply voltage ELVDD; and the switch tube M2, the first conduction end of which is connected with the control end of the drive transistor M1, and the second conduction end of which is connected with the second conduction end of the drive transistor M1, and the voltage of the control end of the switch tube M2 (corresponding to the fourth control signal G_3) is configured to turn on the switch tube M2 in the compensation stage and the writing stage, and turn off the switch tube M2 in the light-emitting stage. The second conduction end of the drive transistor M1 is connected to the control end of the drive transistor M1 in the compensation stage and the writing stage, and the second conduction end of the drive transistor is disconnected from the control end of the drive transistor M1 in the light-emitting stage.

[0051] In addition to the compensation stage, the writing stage, and the light-emitting stage, in the holding stage between the compensation stage and the light-emitting stage, the input module 10 and the state in the compensation stage remain the same, the compensation module 20 disconnects the second conduction end of the drive transistor M1 from the control end of the drive transistor M1, and the drive module 30 disconnects the drive transistor M1 from the power supply voltage ELVDD and the light-emitting diode.

[0052] In the reset stage before the compensation stage, the reset switch M7 is configured to be turned on to reset the anode of the light emitting diode to the reset voltage Vint, and the driving module 30 connects the first and second conduction ends of the driving transistor M1 to the supply voltage ELVDD and the anode voltage of the light emitting diode respectively.

[0053] In one embodiment, the above-mentioned switch M2 is an oxide type NMOS tube, ensuring that the leakage current is in the fA level, and the remaining switches (switches M3-M7) and the driving transistor M1 are P-type low temperature polysilicon (LTPS) thin film transistors. The first conduction end can be the source, and the second conduction end can be the drain.

[0054] In one embodiment, the above-mentioned supply voltage ELVDD, reference voltage Vref, data voltage Vdata, and reset voltage Vint have a potential relationship such as supply voltage ELVDD or data voltage Vdata > reset voltage Vint > reference voltage Vref.

[0055] Figure 3 The working schematic diagram of the OLED pixel circuit of the present application in the compensation stage.

[0056] In the reset stage (corresponding to the T1 period), the first control signal E_1 and the second control signal E_2 are effective, the switch M5 and the switch M6 are turned on, the reset control signal G_2 is effective, the switch M7 is turned on, the fourth control signal G_3 is high, the switch M2 is turned on, and the reset voltage Vint resets the gate voltage of the driving transistor M1 through the switch M7, the switch M6 and the switch M2; the input voltage Vint resets the anode of the OLED through the switch M7; at the same time, the fifth control signal G_4 is effective, the switch M4 is turned on, and the reference voltage Vref is transmitted to the N5 node.

[0057] At this time, the control end-first conduction end voltage Vgs of the driving transistor M1 is Vint-ELVDD, so that all the driving transistors M1 of the pixel circuits can be in the same Vgs bias voltage before the current frame writes the data voltage, and the short-term image sticking of the AMOLED caused by the hysteresis effect of the TFT can be improved. In this stage, the node voltages are shown in Table 1:

[0058] Node Voltage N1 Vint N2 ELVDD N3 Vint N4 Vint N5 Vref

[0059] Table 1

[0060] Figure 4 The working schematic diagram of the OLED pixel circuit of the present application in the compensation stage.

[0061] In the compensation stage (corresponding to the T2 period), the second control signal E_2 is effective, the switch tube M5 is opened, the fourth control signal G_3 is effective, the switch tube M2 is opened, the fifth control signal G_4 is effective, the switch tube M4 is opened, the third capacitor C3 is charged, and the voltage of the N1 node is charged to ELVDD+Vth_M1, so that the threshold voltage compensation of the driving transistor M1 is realized.

[0062] In this stage, the voltages of the nodes are shown in Table 2:

[0063] Node Voltage N1 ELVDD+Vth N2 ELVDD N3 ELVDD+Vth N5 Vref

[0064] Table 2

[0065] Figure 5 The working schematic diagram of the OLED pixel circuit of the present application in the holding stage.

[0066] In the holding stage (corresponding to the T3 period), the fifth control signal G_4 is effective, the switch tube M4 is opened, and the remaining switch tubes are closed, so that the threshold voltage of the driving transistor M1 is held.

[0067] Figure 6 The working schematic diagram of the OLED pixel circuit of the present application in the writing stage.

[0068] In the writing stage (corresponding to the T4 period), the third control signal G_1 is effective, the switch tube M3 is opened, the data voltage Vdata is transmitted to the N5 node, the fourth control signal G_3 is high, the switch tube M2 is opened, the data voltage Vdata is transmitted to the N5 node, and the change amount is coupled to the N1 node through the first capacitor C1 and the compensation module.

[0069] In this stage, the voltages of the nodes are shown in Table 3:

[0070] Node Voltage N1 ELVDD+Vth+(Vdata-Vref)*[C1 / (C1+C2)] N2 ELVDD N3 ELVDD+Vth+(Vdata-Vref)*[C1 / (C1+C2)] N5 Vdata

[0071] Table 3

[0072] Figure 7 The working schematic diagram of the OLED pixel circuit of the present application in the light-emitting stage.

[0073] In the light-emitting stage (corresponding to the T5 period), in the light-emitting stage, the first control signal E_1 and the second control signal E_2 are effective, so that the driving transistor M1, the switch tube M5 and the switch tube M6 are opened, and the remaining switch tubes are closed, the light-emitting diode completes the light-emitting, and the driving voltage expression of the driving transistor M1 does not contain Vth and the supply voltage ELVDD, so that the phenomenon of uneven brightness and picture of the OLED display caused by the inconsistent Vth and the IR drop mentioned in the prior art is eliminated.

[0074] Specifically, in this stage, the N1 node and N2 node voltages are as shown in Table Four, and the OLED saturation region current formula is as follows according to the N1 node and N2 node voltages and the OLED saturation region current formula:

[0075] I oled ∝(Vgs-Vth) 2

[0076] wherein Vgs is the voltage difference between the N1 node and the N2 node, Vth is the threshold voltage of the driving transistor M1, Vgs can be specifically expressed as ELVDD+Vth+(Vdata-Vref)*[C1 / (C1+C2)]-ELVDD, and after simplification, Vgs=Vth+(Vdata-Vref)*[C1 / (C1+C2)] is obtained, and according to the OLED saturation region current formula, I oled =WC ox u / 2L*[(Vdata-Vref)*[C1 / (C1+C2)]] 2 wherein μ is the carrier mobility, W is the channel width, L is the channel length, Cox is the unit area control terminal capacitance, Vth is the threshold voltage of the driving transistor M1, C1, C2 and C3 are the capacitance values of the first capacitor C1 and the second capacitor C2 and the third capacitor C3 respectively, Vdata is the data voltage, Vref is the reference voltage, W and L are fixed in design, and Cox depends on the control terminal insulating layer thickness and material. It can be seen that the Vth is cancelled in the current flowing through the light-emitting diode OLED, the expression of the OLED driving current has nothing to do with Vth and the supply voltage ELVDD, the driving module drives the light-emitting diode according to the potential difference between the N1 node and the N2 node, and therefore the phenomenon of OLED display brightness and picture unevenness caused by inconsistent Vth and IR drop is eliminated.

[0077] ITEM Voltage N1 ELVDD+Vth+(Vdata-Vref)*[C1 / (C1+C2)] N2 ELVDD

[0078] Table Four

[0079] In an embodiment of the present application, a display panel is also provided, comprising the pixel circuit described above, and a plurality of gate lines G1-Gm and a plurality of data lines S1-Sn, the display panel being one of a liquid crystal display panel, a micro 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.

[0080] In one embodiment of the present application, a display device is also provided, comprising the pixel circuit, the source driver circuit, the gate driver circuit, and a plurality of gate lines G1-Gm and a plurality of data lines S1-Sn; the gate driver is configured to provide a gate voltage to the pixel circuit through the plurality of gate lines G1-Gm in a display state; and the source driver is configured to provide a source data voltage to the pixel circuit through the plurality of data lines in the display state for light emitting display.

[0081] It should be noted that the terms "during," "when," and "while" as used herein in relation to the operation of circuitry are not to be construed as strict temporal terms requiring that the actions take place immediately upon the start of the initiating action, but rather that there can be some small, but reasonable, delay or delays between the initiating action and the reaction action it initiates, such as various transmission delays, etc. The use of the term "about" or "substantially" herein means that the element has a value or position that is intended to be close to the stated value or position. However, as is well known in the art, there are always minor variations that make it difficult to be strictly the stated value. It has been properly determined in the art that a variation of at least ten percent (10%) (and at least twenty percent (20%) for semiconductor doping concentrations) is a reasonable variation from the described accurate ideal target. When used in connection with signal states, the actual voltage value or logic state of the signal (e.g., "1" or "0") depends on whether positive logic or negative logic is used.

[0082] In accordance with the embodiments of the present application as described above, these embodiments are not described in detail with all of the possible modifications and alterations. It is apparent that many modifications and changes can be made to the embodiments described above. The present description selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well utilize the present application and make modifications and uses on the basis of the present application. The scope of protection of the present application should be defined by the scope of the claims of the present application and their equivalents.

Claims

1. An OLED pixel circuit, comprising: a driving module including a driving transistor, a control terminal of the driving transistor receiving a node voltage, a first conduction terminal of the driving transistor receiving a supply voltage, and a second conduction terminal of the driving transistor providing a driving current; an input module including a first capacitor, a first terminal of the first capacitor being connected to the second conduction terminal of the driving transistor, and a second terminal of the first capacitor receiving a reference voltage in a compensation phase and receiving a data voltage in a writing phase; a compensation module configured to compensate the node voltage, including a second capacitor and a third capacitor connected in series between the first conduction terminal and the control terminal of the driving transistor, and a connection node of the second capacitor and the third capacitor receiving the supply voltage; and a light emitting diode connected to the driving transistor to receive the driving current, wherein the compensation module is configured to connect the second conduction terminal of the driving transistor to the control terminal of the driving transistor in the compensation phase, and charge the third capacitor, so that the node voltage is compensated to a first voltage; and maintain a driving voltage after the compensation phase, the light emitting diode generating an effective brightness corresponding to the data voltage in a light emitting phase according to the driving current, the driving voltage being equal to a sum of the first voltage and a second voltage, the first voltage being equal to a sum of the supply voltage and a threshold voltage of the driving transistor, and the second voltage being related to a difference between the data voltage and the reference voltage. An operation cycle of the OLED pixel circuit includes: a holding phase arranged between the compensation phase and the light emitting phase, a state of the input module in the holding phase and the compensation phase is consistent, the compensation module disconnects the second conduction terminal of the driving transistor from the control terminal of the driving transistor in the holding phase, and the driving module disconnects the driving transistor from the supply voltage and the light emitting diode in the holding phase. The operation cycle of the OLED pixel circuit further includes:

2. The OLED pixel circuit of claim 1, wherein, the compensation phase, the driving module connects the first conduction terminal of the driving transistor to the supply voltage, and disconnects the second conduction terminal of the driving transistor from an anode of the light emitting diode in the compensation phase; the light emitting phase, the driving module connects the first conduction terminal of the driving transistor to the supply voltage, and connects the second conduction terminal of the driving transistor to the anode of the light emitting diode in the light emitting phase; and the writing phase arranged between the compensation phase and the light emitting phase, the input module and the compensation module adjust the node voltage to the driving voltage in the writing phase, and the driving module disconnects the driving transistor from the supply voltage and the anode of the light emitting diode in the writing phase. The input module further includes a first switch and a second switch, 3. The OLED pixel circuit of claim 2, wherein, ​ a first conduction end of the first switch tube receives a reference voltage, a first conduction end of the second switch tube receives the data voltage, a second conduction end of the first switch tube is connected with a second conduction end of the second switch tube and connected to a second end of the first capacitor, a control end voltage of the first switch tube is configured to turn on the first switch tube in the compensation phase, and turn off the first switch tube in the write-in phase and the light-emitting phase, a control end voltage of the second switch tube is configured to turn on the second switch tube in the write-in phase, and turn off the second switch tube in the compensation phase and the light-emitting phase.

4. The OLED pixel circuit of claim 2, wherein, The compensation module comprises: a second capacitor and a third capacitor connected in series between the first conduction end and the control end of the drive transistor, a connection node of the second capacitor and the third capacitor receiving the power supply voltage; and a third switch tube, a first conduction end of which is connected with the control end of the drive transistor, and a second conduction end of which is connected with the second conduction end of the drive transistor, a control end voltage of the third switch tube being configured to turn on the third switch tube in the compensation phase and the write-in phase, and turn off the third switch tube in the light-emitting phase.

5. The OLED pixel circuit of claim 4, wherein the third switch tube is an N-type channel MOS thin film transistor.

6. The OLED pixel circuit of claim 2, wherein, The working cycle further comprises a reset phase, which is arranged before the compensation phase, The OLED pixel circuit further comprises a reset switch tube, a control end voltage of the reset switch tube being configured to turn on the reset switch tube in the reset phase to reset the anode of the light-emitting diode to a reset voltage, In the reset phase, the drive module connects the first conduction end and the second conduction end of the drive transistor to the power supply voltage and the anode voltage of the light-emitting diode respectively, and the voltage between the control end and the first conduction end of the drive transistor is the difference between the reset voltage and the power supply voltage.

7. The OLED pixel circuit of claim 1, wherein, The drive module comprises: a fourth switch tube connected between the power supply voltage and the first conduction end of the drive transistor, for controlling the conduction and turn-off between the first conduction end of the drive transistor and the power supply voltage; and a fifth switch tube connected between the second conduction end of the drive transistor and the anode of the light-emitting diode, for controlling the conduction and turn-off between the drive transistor and the light-emitting diode.

8. A display panel comprising a plurality of OLED pixel circuits according to any one of claims 1-7, the display panel being one 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.

9. A driving method of an OLED pixel circuit, applied to the OLED pixel circuit according to any one of claims 1-7, wherein, comprises: in the compensation phase, connecting the second conduction end of the drive transistor to the control end of the drive transistor, and charging the third capacitor, so that the node voltage is compensated to the first voltage; In a light emitting stage after the compensation stage, a control terminal voltage of the drive transistor is controlled to keep a drive voltage, so that the drive transistor provides a drive current according to the drive voltage, and the light emitting diode generates an effective brightness corresponding to the data voltage according to the drive current. The drive voltage is equal to a sum of the first voltage and the second voltage, the first voltage is equal to a sum of the supply voltage and a threshold voltage of the drive transistor, and the second voltage is related to a difference between the data voltage and a reference voltage.

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