Micro light emitting diode pixel circuit and driving method

Abstract

The application discloses a micro light emitting diode pixel circuit, a driving method and a display device. The pixel circuit comprises an initialization module, a threshold voltage compensation module and a load driving module; the initialization module is connected with the threshold voltage compensation module and the load driving module, and is used for initializing the threshold voltage compensation module and the load driving module through a reference voltage under the control of an initialization signal; the threshold voltage compensation module is connected with the load driving module, and is used for compensating the threshold voltage of the load driving module through a data voltage under the control of a scanning signal, so as to obtain a driving voltage for driving a light emitting device of the load driving module; and the load driving module is used for converting the driving voltage provided by the threshold voltage compensation module into a light emitting current for driving the light emitting device under the control of a stable control signal and a light emitting control signal. The micro light emitting diode pixel circuit provided by the application can further improve the compensation effect of threshold voltage drift.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a micro light emitting diode pixel circuit, a driving method and a display device. BACKGROUND

[0002] Traditional liquid crystal display (LCD) is a voltage driven device, while organic light emitting diode (OLED) and micro light emitting diode (Micro-LED) are current driven devices, which are more sensitive to the electrical variation of thin film transistor (TFT). In the existing Micro-LED display, each pixel point is driven by an independent pixel driving circuit. However, with the increase of use time, the threshold voltage of the driving transistor of the Micro-LED pixel driving circuit of the existing Micro-LED display will drift, resulting in unstable display and uneven brightness display of the display screen.

[0003] In order to solve the problem of threshold voltage drift, a pixel compensation circuit is usually used to compensate the threshold voltage during design. One of the existing pixel compensation circuits uses a 7T1C pixel circuit, the circuit structure of which is shown in Figure 1 , and the timing diagram is shown in Figure 2The driving process of the pixel driving circuit mainly includes three stages: an initialization stage T1, a threshold voltage compensation stage T2, and a light emitting stage T3. In the initialization stage T1, under the control of an initialization signal S1, the first initialization transistor M5 and the second initialization transistor M7 are turned on. The turned-on first initialization transistor M5 provides a high-level first reference voltage Vref1 to the control end of the driving transistor M3 and the second end of the storage capacitor C1, so as to initialize the voltage of the control end of the driving transistor M3 and the second end of the storage capacitor C1. The turned-on second initialization transistor M7 provides a low-level second reference voltage Vref2 to the anode of the light emitting device D1 and the first end of the storage capacitor C1, so as to initialize the voltage of the anode of the light emitting device D1 and the first end of the storage capacitor C1. At this time, the voltage stored in the storage capacitor C1 is Vc1=Vref1-Vref2. In the threshold voltage compensation stage T2, under the control of a scanning signal S2, the data writing transistor M2 and the threshold compensation transistor M4 are turned on. The turned-on data writing transistor M2 provides a data voltage Vdata to the second channel end of the driving transistor M3. The turned-on threshold compensation transistor M4 shorts the control end and the first channel end of the driving transistor M3, so that the driving transistor M3 forms a diode connection structure. The charge stored in the storage capacitor C1 is discharged through the turned-on driving transistor M3 and the threshold compensation transistor M4, until the voltage of the control end of the driving transistor M3 is Vg=Vdata+Vth. At this time, the voltage stored in the storage capacitor C1 is Vc1=Vdata+Vth. In the light emitting stage T3, under the control of a light emitting control signal Vemit, the first light emitting control transistor M1 and the second light emitting control transistor M6 are turned on. The turned-on first light emitting control transistor M1 provides a power supply voltage VDD to the first channel end of the driving transistor M3. The voltage stored in the storage capacitor C1 is applied to the control end of the driving transistor M3. The driving transistor M3 is turned on. The turned-on light emitting control transistor M6 turns on the second channel end of the driving transistor M3 and the anode of the light emitting device D1. In this case, the voltage of the control end and the second channel end of the driving transistor M3, i.e., the gate-source voltage Vgs, is the same as the voltage across the storage capacitor C1, i.e., Vgs=Vc1=Vdata+Vth. At this time, the driving transistor M3 works in a saturation state, and the light emitting current I flowing through the light emitting device D1 is I=k(Vgs-Vth)=k(Vdata+Vth-Vth)=k(Vdata) 2 2 wherein k is a constant related to the material and size of the driving transistor M3. It can be seen that the light emitting current flowing through the light emitting device D1 is irrelevant to the threshold voltage of the driving transistor M3, and the purpose of compensating the threshold voltage is achieved, and the influence of the threshold voltage drift on the light emitting current of the light emitting device D1 is eliminated to a certain extent. Figure 1 ​Simulation data of the change of the pixel light-emitting current when the threshold voltage of the driving transistor of the 7T1C pixel circuit shown in the middle of the figure drifts is as shown in the table below Figure 3 As can be seen from the simulation results, the compensation effect of the above-mentioned scheme still needs to be improved, and when the threshold voltage of the driving TFT drifts by 2V, the light-emitting current of the Micro-LED decreases by about 20%, which may cause the light-emitting currents of the pixels to be uneven in size, thereby forming the phenomenon that the display image is uneven.

[0004] The existing 7T1C pixel circuit adopts 7 TFTs and 6 driving waveforms, and the circuit structure is relatively complex. Because the pixel area of a high-resolution screen is usually small, the complex circuit structure limits the areas of the storage capacitor and the driving transistor, and the compensation effect of the threshold voltage drift is not ideal.

[0005] Therefore, it is necessary to provide an improved technical scheme to further improve the compensation effect of the threshold voltage drift. SUMMARY

[0006] In view of the above problems, the purpose of the present application is to provide a micro light-emitting diode pixel circuit, a driving method and a display device, which can further improve the compensation effect of the threshold voltage drift.

[0007] The present application provides a micro light-emitting diode pixel circuit, comprising an initialization module, a threshold voltage compensation module and a load driving module; the initialization module is connected with the threshold voltage compensation module and the load driving module, used for receiving an initialization signal and a reference voltage, and initializing the threshold voltage compensation module and the load driving module through the reference voltage under the control of the initialization signal; the threshold voltage compensation module is connected with the load driving module, used for receiving a scanning signal and a data voltage, and compensating the threshold voltage of the load driving module through the data voltage under the control of the scanning signal, so as to obtain a driving voltage for driving the light-emitting device of the load driving module; the load driving module is connected with the threshold voltage compensation module, used for receiving a light-emitting control signal, a stable control signal and a power voltage, and converting the driving voltage provided by the threshold voltage compensation module into a light-emitting current for driving the light-emitting device under the control of the stable control signal and the light-emitting control signal.

[0008] Preferably, the initialization module comprises an initialization transistor; the control end of the initialization transistor is used for receiving the initialization signal, the first passage end of the initialization transistor is electrically connected with the threshold voltage compensation module and the load driving module, and the second passage end of the initialization transistor is used for receiving the reference voltage.

[0009] Preferably, the threshold voltage compensation module comprises a storage capacitor, a threshold compensation transistor and a data write transistor; a first end of the storage capacitor is electrically connected with a first passage end of the initialization transistor and the load driving module; a second end of the storage capacitor is electrically connected with a first passage end of the threshold compensation transistor and the load driving module; a control end of the threshold compensation transistor is used for receiving the scan signal; a first passage end of the threshold compensation transistor is electrically connected with the load driving module; a second passage end of the threshold compensation transistor is also electrically connected with the load driving module; a control end of the data write transistor is also used for receiving the scan signal; a first passage end of the data write transistor is used for receiving the data voltage; and a second passage end of the data write transistor is electrically connected with the load driving module.

[0010] Preferably, the load driving module comprises a stabilization transistor, a driving transistor, a light-emitting control transistor and a light-emitting device; a control end of the stabilization transistor is used for receiving a stabilization control signal; a first passage end of the stabilization transistor is used for receiving the power supply voltage; a second passage end of the stabilization transistor is electrically connected with a first passage end of the driving transistor and a second passage end of the threshold compensation transistor; a control end of the driving transistor is electrically connected with a first passage end of the threshold compensation transistor and a second end of the storage capacitor; a first passage end of the driving transistor is also electrically connected with a second passage end of the threshold compensation transistor; a second passage end of the driving transistor is electrically connected with a first passage end of the light-emitting control transistor and a second passage end of the data write transistor; a control end of the light-emitting control transistor is used for receiving the light-emitting control signal; a second passage end of the light-emitting control transistor is electrically connected with an anode of the light-emitting device; and a cathode of the light-emitting device is electrically connected with a ground end.

[0011] The application further provides a driving method of the micro light-emitting diode pixel circuit, which is applied to the micro light-emitting diode pixel circuit as described above and comprises the following steps:

[0012] S01, the initialization module is controlled to initialize the threshold voltage compensation module and the load driving module, the threshold voltage compensation module is controlled to receive the data voltage and compensate the threshold voltage of the load driving module, so as to obtain a driving voltage for driving the light-emitting device of the load driving module;

[0013] S02, the threshold voltage compensation module is controlled to continue receiving the data voltage and compensating the threshold voltage of the load driving module;

[0014] S03, the load driving module is controlled to convert the driving voltage into a light-emitting current, so that the light-emitting device of the load driving module emits light.

[0015] Preferably, the step S01 further comprises: controlling the initialization transistor to be turned on by the initialization signal, controlling the stabilization transistor to be turned on by the stabilization control signal, controlling the data write transistor and the threshold compensation transistor to be turned on by the scan signal, making the drive transistor form a diode electrical connection structure, and controlling the light emitting control transistor to be turned off by the light emitting control signal.

[0016] Preferably, the step S02 further comprises: controlling the data write transistor and the threshold compensation transistor to continue to be turned on by the scan signal, making the drive transistor continue to form a diode electrical connection structure, controlling the stabilization transistor to be turned off by the stabilization control signal, controlling the light emitting control transistor to continue to be turned off by the light emitting control signal, and controlling the initialization transistor to be turned off by the initialization signal.

[0017] Preferably, the step S03 further comprises: controlling the stabilization transistor to be turned on by the stabilization control signal, controlling the drive transistor to be turned on by the drive voltage, controlling the light emitting control transistor to be turned on by the light emitting control signal, controlling the data write transistor and the threshold compensation transistor to be turned off by the scan signal, and controlling the initialization transistor to be turned off by the initialization signal.

[0018] Preferably, the current flowing through the light emitting device in the step S01 is less than the light emitting current flowing through the light emitting device in the step S03.

[0019] The present application further provides a display device comprising the micro light emitting diode pixel circuit as described above.

[0020] Compared with the prior art, the micro light emitting diode pixel circuit and the display device provided by the present application comprise a stabilization transistor, a data write transistor, a drive transistor, a threshold compensation transistor, a light emitting control transistor, an initialization transistor, a storage capacitor and a light emitting device. The selective turn-on of the six transistors in the initialization stage, the threshold voltage compensation stage and the light emitting stage, and the compensation of the threshold voltage by the storage capacitor, save one transistor, simplify the circuit, and further improve the compensation effect of the threshold voltage drift of the drive transistor. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as a limitation on the scope. Other related drawings can also be obtained by those skilled in the art without creative labor.

[0022] Figure 1 This is a circuit diagram of an existing 7T1C pixel circuit;

[0023] Figure 2 This is a timing diagram of an existing 7T1C pixel circuit;

[0024] Figure 3 This is a schematic diagram of simulation data showing the change in pixel emission current when the threshold voltage of the driving transistor in an existing 7T1C pixel circuit drifts.

[0025] Figure 4 This is a circuit diagram of a miniature light-emitting diode pixel circuit according to an embodiment of the present invention;

[0026] Figure 5 This is a timing diagram of a miniature light-emitting diode pixel circuit according to an embodiment of the present invention;

[0027] Figure 6 This is a simulation comparison diagram of the threshold voltage offset compensation effect between a miniature light-emitting diode pixel circuit according to an embodiment of the present invention and the existing 7T1C pixel circuit described above. Detailed Implementation

[0028] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of preferred embodiments with reference to the accompanying drawings. Through the description of the specific embodiments, a more in-depth and specific understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the present invention; some well-known parts may not be shown. In the various drawings, the same elements are represented by similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale.

[0029] One embodiment of the present invention provides a miniature light-emitting diode pixel circuit, such as... Figure 4 As shown, the miniature light-emitting diode pixel circuit includes an initialization module 110, a threshold voltage compensation module 120, and a load driving module 130.

[0030] The initialization module 110 is connected with the threshold voltage compensation module 120 and the load driving module 130, and is used for receiving an initialization signal S1 and a reference voltage Vref2, and initializing the threshold voltage compensation module 120 and the load driving module 130 under the control of the initialization signal S1 through the reference voltage Vref2; the threshold voltage compensation module 120 is connected with the load driving module 130, and is used for receiving a scanning signal S2 and a data voltage Vdata, and compensating a threshold voltage of the load driving module 130 under the control of the scanning signal S2 through the data voltage Vdata, so as to obtain a driving voltage for driving a light emitting device D1 of the load driving module 130; the load driving module 130 is connected with the threshold voltage compensation module 120, and is used for receiving a light emitting control signal Vemit, a stabilization control signal S3 and a power supply voltage VDD, and converting the driving voltage provided by the threshold voltage compensation module 120 into a light emitting current for driving the light emitting device D1 under the control of the stabilization control signal S3 and the light emitting control signal Vemit.

[0031] Specifically, the initialization signal S1, the stabilization control signal S3, the scanning signal S2 and the light emitting control signal Vemit are all provided by an external timing controller.

[0032] Specifically, the initialization module 110 includes an initialization transistor M7; a control end of the initialization transistor M7 is used for receiving the initialization signal S1, a first passage end of the initialization transistor M7 is electrically connected with the threshold voltage compensation module 120 and the load driving module 130, and a second passage end of the initialization transistor M7 is used for receiving the reference voltage Vref2.

[0033] Specifically, the threshold voltage compensation module 120 includes a storage capacitor C1, a threshold compensation transistor M4 and a data writing transistor M2; a first end of the storage capacitor C1 is electrically connected with the first passage end of the initialization transistor M7 and the load driving module 130, and a second end of the storage capacitor C1 is electrically connected with a first passage end of the threshold compensation transistor M4 and the load driving module 130; a control end of the threshold compensation transistor M4 is used for receiving the scanning signal S2, the first passage end of the threshold compensation transistor M4 is electrically connected with the load driving module 130, and a second passage end of the threshold compensation transistor M4 is also electrically connected with the load driving module 130; a control end of the data writing transistor M2 is also used for receiving the scanning signal S2, a first passage end of the data writing transistor M2 is used for receiving the data voltage Vdata, and a second passage end of the data writing transistor M2 is electrically connected with the load driving module 130.

[0034] Specifically, the load driving module 130 includes a stabilizing transistor M1, a driving transistor M3, a light-emitting control transistor M6, and a light-emitting device D1. The control terminal of the stabilizing transistor M1 is used to receive a stabilizing control signal S3, and the first path terminal of the stabilizing transistor M1 is used to receive the power supply voltage VDD. The second path terminal of the stabilizing transistor M1 is electrically connected to the first path terminal of the driving transistor M3 and the second path terminal of the threshold compensation transistor M4. The control terminal of the driving transistor M3 is electrically connected to the first path terminal of the threshold compensation transistor M4 and the second terminal of the storage capacitor C1. The first path terminal of the driving transistor M3 is also electrically connected to the second path terminal of the threshold compensation transistor M4. The second path terminal of the driving transistor M3 is electrically connected to the first path terminal of the light-emitting control transistor M6 and the second path terminal of the data writing transistor M2. The control terminal of the light-emitting control transistor M6 is used to receive a light-emitting control signal Vemit, and the second path terminal of the light-emitting control transistor M6 is electrically connected to the anode of the light-emitting device D1. The cathode of the light-emitting device D1 is electrically connected to the ground terminal.

[0035] In some embodiments of the present invention, the light-emitting device D1 can be a light-emitting diode (LED), an organic light-emitting diode (OLED), a micro-LED, a mini-LED, an inorganic light-emitting diode (QLED), etc.

[0036] It should be noted that all the transistors mentioned above are N-type transistors; the same principle can also be applied to P-type transistors with slight modifications to the circuit connections. Furthermore, the control terminal of each transistor is the gate, the first pass terminal can be the source, and the second pass terminal can be the drain; alternatively, the first pass terminal can be the drain, and the second pass terminal can be the source.

[0037] Another embodiment of the present invention provides a driving method for a micro light-emitting diode pixel circuit, which is applied to the micro light-emitting diode pixel circuit described above;

[0038] The miniature light-emitting diode pixel circuit is as follows: Figure 4 As shown, the module includes an initialization transistor M7 in the initialization module 110, a storage capacitor C1, a threshold compensation transistor M4, and a data writing transistor M2 in the threshold voltage compensation module 120, and a stabilizing transistor M1, a driving transistor M3, a light-emitting control transistor M6, and a light-emitting device D1 in the load driving module 130. The driving method includes:

[0039] S01, the control initialization module 110 initializes the threshold voltage compensation module 120 and the load driving module 130, controls the threshold voltage compensation module 120 to receive the data voltage Vdata and compensate the threshold voltage of the load driving module 130 to obtain the driving voltage of the light-emitting device D1 used to drive the load driving module 130.

[0040] S02, the control threshold voltage compensation module 120 continues to receive the data voltage Vdata and performs threshold voltage compensation on the load driving module 130;

[0041] S03, the control load driving module 130 converts the driving voltage into the light emitting current, and makes the light emitting device D1 of the load driving module 130 emit light.

[0042] In an embodiment of the present application, as shown in Figure 5 The combination of the initialization signal S1, the stable control signal S3, the scan signal S2 and the light emitting control signal Vemit corresponds to the initialization stage, the threshold voltage compensation stage and the light emitting stage in sequence. Taking the N-type transistor as an example, the driving method of the micro light emitting diode pixel circuit shown in Figure 5 The combination of the initialization signal S1, the stable control signal S3, the scan signal S2 and the light emitting control signal Vemit corresponds to the initialization stage, the threshold voltage compensation stage and the light emitting stage in sequence. Taking the N-type transistor as an example, the driving method of the micro light emitting diode pixel circuit shown in Figure 4 The combination of the initialization signal S1, the stable control signal S3, the scan signal S2 and the light emitting control signal Vemit corresponds to the initialization stage, the threshold voltage compensation stage and the light emitting stage in sequence. Taking the N-type transistor as an example, the driving method of the micro light emitting diode pixel circuit shown in

[0043] In the initialization stage T1, the initialization signal S1 is a high level signal, which controls the initialization transistor M7 to be in the conducting state; the scan signal S2 is also a high level signal, which controls the data writing transistor M2 and the threshold compensation transistor M4 to be in the conducting state; the stable control signal S3 is also a high level signal, which controls the stable transistor M1 to be in the conducting state. The light emitting control signal Vemit is a low level signal, which controls the light emitting control transistor M6 to be in the cut-off state.

[0044] In the initialization stage T1, the turned-on initialization transistor M7 provides the low-level reference voltage Vref2 to the anode of the light emitting device D1 and the first terminal of the storage capacitor C1, for initializing the anode of the light emitting device D1 and alleviating the aging of the light emitting device D1. It should be noted that the current flowing through the light emitting device D1 is small at this time, and the light emitting device D1 does not emit light. The voltage at the first terminal of the storage capacitor C1 is also initialized, so as to avoid the influence of the residual signal of the previous image frame on the display picture of the current image frame. The turned-on stable transistor M1 provides the power supply voltage VDD to the first pass terminal of the driving transistor M3, so that the voltage Vd at the fifth node NET5, i.e., the first pass terminal of the driving transistor M3, is Vnet5=VDD. The turned-on threshold compensation transistor M4 provides the power supply voltage VDD to the control terminal of the driving transistor M3, so that the voltage Vg at the first node NET1, i.e., the control terminal of the driving transistor M3, is Vnet1=VDD. At this time, the voltage across the storage capacitor C1 is Vc1=VDD-Vref2. The turned-on data write transistor M2 provides the data voltage Vdata to the second pass terminal of the driving transistor M3. The turned-on threshold compensation transistor M4 shorts the control terminal and the first pass terminal of the driving transistor M3, so that the driving transistor M3 forms a diode connection structure, and thus the driving transistor M3 is also in the turned-on state. The above-mentioned data voltage Vdata is lower than the voltage VDD with respect to the voltage at the second terminal of the storage capacitor C1. Therefore, the charge stored in the storage capacitor C1 is discharged through the turned-on driving transistor M3, so that the potential of the first node NET1 continuously decreases. When the voltage Vgs-Vth at the control terminal and the second pass terminal of the driving transistor M3 is 0, Vth is the threshold voltage of the driving transistor M3, the driving transistor M3 is cut off, and the above-mentioned storage capacitor C1 stops discharging. At this time, the voltage at the control terminal of the driving transistor M3 is Vg=Vnet1=Vdata+Vth. At this time, the voltage stored in the storage capacitor C1 is Vc1=Vdata+Vth-Vref2.

[0045] In the threshold voltage compensation stage T2, the scanning signal S2 is still a high-level signal, the turned-on data write transistor M2 and the turned-on threshold compensation transistor M4 are still in the turned-on state. The initialization signal S1 is a low-level signal, the turned-off initialization transistor M7 is in the cut-off state. The stable control signal S3 is a low-level signal, the turned-off stable transistor M1 is in the cut-off state, and the light emitting control signal Vemit is still a low-level signal, the turned-off light emitting control transistor M6 is in the cut-off state.

[0046] In the threshold voltage compensation stage T2, the turned-on data write transistor M2 continues to provide the data voltage Vdata to the second path terminal of the drive transistor M3, and the turned-on threshold compensation transistor M4 continues to short the control terminal and the first path terminal of the drive transistor M3, so that the drive transistor M3 forms a diode connection structure and is in the turned-on state. At this time, the voltage of the second terminal of the storage capacitor C1 is still greater than the data voltage Vdata, so the charge stored in the storage capacitor C1 continues to discharge through the turned-on drive transistor M3 and threshold compensation transistor M4, so that the voltage of the first node NET1 becomes Vdata+Vth. At this time, the voltage of the control terminal of the drive transistor M3 is Vg=Vnet1=Vdata+Vth, and the voltage stored in the storage capacitor C1 is Vc1=Vdata+Vth.

[0047] In the light emitting stage T3, the stable control signal S3 is a high-level signal, the stable transistor M1 is controlled to be in the turned-on state, the light emitting control signal Vemit is a high-level signal, and the light emitting control transistor M6 is controlled to be in the turned-on state. The scanning signal S2 is a low-level signal, the data write transistor M2 and the threshold compensation transistor M4 are controlled to be in the cut-off state, and the initialization signal S1 is still a low-level signal, and the initialization transistor M7 is still in the cut-off state.

[0048] In the light emitting stage T3, the turned-on light emitting control transistor M6 provides the power supply voltage VDD to the first path terminal of the drive transistor M3, the storage capacitor C1 is connected across the control terminal and the second path terminal (for example, the source) of the drive transistor M3, and the voltage stored in the storage capacitor C1 is applied to the control terminal of the drive transistor M3, so that the drive transistor M3 is turned on, and the turned-on light emitting control transistor M6 turns on the second path terminal of the drive transistor M3 and the anode of the light emitting device D1. In this case, the voltage of the control terminal and the second path terminal of the drive transistor M3, i.e., the gate-source voltage Vgs, is the same as the voltage across the storage capacitor C1, i.e., Vgs=Vc1=Vdata+Vth. At this time, the turned-on stable transistor M1 provides the power supply voltage VDD to the first path terminal of the drive transistor M3, so that the drive transistor M3 works in the saturation state. In this case, the current path between the power supply voltage VDD terminal and the ground terminal GND is turned on, and the light emitting current I flowing through the light emitting device D1 is: I=k(Vgs-Vth) 2 =k(Vdata+Vth-Vth) 2 =k(Vdata) 2wherein k is a constant related to the material and size of the driving transistor M3. Thus, it can be seen that the light emitting current flowing through the light emitting device D1 of the micro light emitting diode pixel circuit is irrelevant to the threshold voltage of the driving transistor M3, and the purpose of compensating the threshold voltage is achieved, and the influence of the threshold voltage drift on the light emitting current of the light emitting device D1 is eliminated to a certain extent.

[0049] It should be noted that the absolute values of the high level signal and the low level signal can be equal or unequal. For example, the high level is a value greater than 0, and the low level is 0V, or the high level is 0V, and the low level is a value less than 0. In actual application, the design is determined according to actual needs, which is not limited here.

[0050] The micro light emitting diode pixel circuit provided by the application uses a new stable control signal S3 to replace the first reference voltage Vref1 in the prior art 7T1C pixel circuit with the power supply voltage VDD in the initialization stage T1, thereby saving one transistor, i.e. the first initialization transistor M5 in the 7T1C pixel circuit. And the data voltage Vdata is written into the second passage end of the driving transistor M3 in the initialization stage T1, which increases the compensation time of the threshold voltage, and further improves the compensation effect. As shown in Figure 6 The simulation comparison diagram of the threshold voltage offset compensation effect of the pixel circuit in the embodiment of the application and the above-mentioned existing 7T1C pixel circuit is shown. Compared with the original 7T1C pixel circuit, the micro light emitting diode pixel circuit provided by the application significantly improves the compensation effect for the threshold voltage drift of the driving transistor. In addition, the space saved by reducing one transistor can be used to increase the storage capacitor and the driving transistor channel width, thereby further strengthening the compensation effect.

[0051] In the description of the application, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances. The terms "first", "second" and the like are only used to distinguish similar attributes of elements, and do not indicate or imply relative importance or a specific order. The terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, in addition to including the listed elements, other elements not explicitly listed can also be included.

[0052] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A micro light emitting diode pixel circuit, characterized by, The initialization module, the threshold voltage compensation module and the load driving module are connected, and the initialization module is configured to receive an initialization signal and a reference voltage, and initialize the threshold voltage compensation module and the load driving module by the reference voltage under control of the initialization signal in an initialization stage. The threshold voltage compensation module and the load driving module are connected, and the threshold voltage compensation module is configured to receive a scanning signal and a data voltage, and compensate a threshold voltage of the load driving module by the data voltage under control of the scanning signal in the initialization stage and a threshold voltage compensation stage, so as to obtain a driving voltage for driving a light emitting device of the load driving module. The load driving module is configured to receive a light emitting control signal, a stabilization control signal and a power supply voltage, and convert the driving voltage provided by the threshold voltage compensation module into a light emitting current for driving the light emitting device under control of the stabilization control signal and the light emitting control signal in a light emitting stage. The threshold voltage compensation module comprises a threshold compensation transistor and a data writing transistor. The control end of the threshold compensation transistor is configured to receive the scanning signal, the first passage end of the threshold compensation transistor is electrically connected with the load driving module, and the second passage end of the threshold compensation transistor is also electrically connected with the load driving module. The control end of the data writing transistor is also configured to receive the scanning signal, the first passage end of the data writing transistor is configured to receive the data voltage, and the second passage end of the data writing transistor is electrically connected with the load driving module. The load driving module comprises a stabilization transistor, a driving transistor and a light emitting control transistor. The control end of the stabilization transistor is configured to receive the stabilization control signal, the first passage end of the stabilization transistor is configured to receive the power supply voltage, and the second passage end of the stabilization transistor is electrically connected with the first passage end of the driving transistor and the second passage end of the threshold compensation transistor. The control end of the driving transistor is electrically connected with the first passage end of the threshold compensation transistor and the second end of a storage capacitor, the first passage end of the driving transistor is also electrically connected with the second passage end of the threshold compensation transistor, and the second passage end of the driving transistor is electrically connected with the first passage end of the light emitting control transistor and the second passage end of the data writing transistor. The control end of the light emitting control transistor is configured to receive the light emitting control signal, and the second passage end of the light emitting control transistor is electrically connected with an anode of the light emitting device. ​ In the initialization stage, the scanning signal is high, the data write transistor and the threshold compensation transistor are controlled to be in the on state, the on data write transistor provides the data voltage to the second path end of the driving transistor, the on threshold compensation transistor shorts the control end and the first path end of the driving transistor, so that the driving transistor forms a diode electric connection structure in the on state, and the storage capacitor discharges through the driving transistor, so that the voltage of the control end of the driving transistor is the sum of the data voltage and the threshold voltage of the driving transistor; In the threshold voltage compensation stage, the scanning signal is still a high signal, the data write transistor and the threshold compensation transistor are still controlled to be in the on state, the on data write transistor continues to provide the data voltage to the second path end of the driving transistor, the on threshold compensation transistor continues to short the control end and the first path end of the driving transistor, so that the driving transistor forms a diode electric connection structure continues to be in the on state, and the storage capacitor continues to discharge through the on driving transistor and the threshold compensation transistor, so that the voltage of the control end of the driving transistor continues to be the sum of the data voltage and the threshold voltage of the driving transistor.

2. The micro light emitting diode pixel circuit of claim 1, wherein, The initialization module comprises an initialization transistor; The control end of the initialization transistor is used for receiving the initialization signal, the first path end of the initialization transistor is electrically connected with the threshold voltage compensation module and the load driving module, and the second path end of the initialization transistor is used for receiving the reference voltage.

3. The micro light emitting diode pixel circuit of claim 2, wherein, The threshold voltage compensation module further comprises a storage capacitor; The first end of the storage capacitor is electrically connected with the first path end of the initialization transistor and the load driving module, and the second end of the storage capacitor is electrically connected with the first path end of the threshold compensation transistor and the load driving module.

4. The micro light emitting diode pixel circuit of claim 3, wherein, The load driving module further comprises a light emitting device, and the cathode of the light emitting device is electrically connected with the ground end.

5. A driving method of a micro light emitting diode pixel circuit, applied to the micro light emitting diode pixel circuit according to any one of claims 1 to 4, characterized in that ； S01, in the initialization stage, the initialization module is controlled to initialize the threshold voltage compensation module and the load driving module, the threshold voltage compensation module is controlled to receive a data voltage and compensate the threshold voltage of the load driving module, so as to obtain a driving voltage for driving the light emitting device of the load driving module; S02, in the threshold voltage compensation stage, the threshold voltage compensation module is controlled to continue to receive the data voltage and compensate the threshold voltage of the load driving module; S03, in the light emitting stage, the load driving module is controlled to convert the driving voltage into a light emitting current, so that the light emitting device of the load driving module emits light.

6. The driving method of the micro light emitting diode pixel circuit according to claim 5, wherein The step S01 further comprises: turning on the initialization transistor by the initialization signal, turning on the stabilization transistor by the stabilization control signal, turning on the data write transistor and the threshold compensation transistor by the scan signal, making the drive transistor form a diode electric connection structure, and turning off the light emitting control transistor by the light emitting control signal.

7. The driving method of the micro light emitting diode pixel circuit according to claim 5, wherein The step S02 further comprises: continuing to turn on the data write transistor and the threshold compensation transistor by the scan signal, continuing to make the drive transistor form a diode electric connection structure, turning off the stabilization transistor by the stabilization control signal, continuing to turn off the light emitting control transistor by the light emitting control signal, and turning off the initialization transistor by the initialization signal.

8. The driving method of the micro light emitting diode pixel circuit according to claim 5, wherein The step S03 further comprises: turning on the stabilization transistor by the stabilization control signal, turning on the drive transistor by the drive voltage, turning on the light emitting control transistor by the light emitting control signal, turning off the data write transistor and the threshold compensation transistor by the scan signal, and turning off the initialization transistor by the initialization signal.

9. The driving method of the micro light emitting diode pixel circuit according to claim 5, wherein The current flowing through the light emitting device in the step S01 is less than the light emitting current flowing through the light emitting device in the step S03.

10. A display device, characterized by comprising: A micro light emitting diode pixel circuit comprising any one of claims 1 to 4.

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