CN115775524A - Micro light-emitting diode pixel circuit and driving method - Google Patents
Micro light-emitting diode pixel circuit and driving method Download PDFInfo
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Abstract
The invention 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 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 the data voltage under the control of the scanning signal so as to obtain the driving voltage for driving the light-emitting device of the load driving module; 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 the stabilization control signal and the light emitting control signal. The micro light-emitting diode pixel circuit provided by the invention can further improve the compensation effect of threshold voltage drift.
Description
Technical Field
The invention 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
A conventional Liquid Crystal Display (LCD) belongs to a voltage-driven type device, and an organic light-Emitting Diode (OLED) and a Micro-LED (Micro-LED) both belong to current-driven types and are sensitive to electrical variation of a Thin Film Transistor (TFT). Each pixel point in the existing Micro-LED display is driven by an independent pixel driving circuit, however, the existing Micro-LED display can cause the threshold voltage of a driving transistor of the Micro-LED pixel driving circuit to drift along with the increase of the service time, so that the phenomena of unstable display of a display screen, uneven brightness display and the like are caused.
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 conventional pixel compensation circuits is a 7T1C pixel circuit, and the circuit structure thereof is shown in fig. 1, and the timing diagram thereof is shown in fig. 2. The driving process of the pixel driving circuit mainly comprises three stages: an initialization stage T1, a threshold voltage compensation stage T2 and a light-emitting stage T3. In an 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 terminal of the driving transistor M3 and the second terminal of the storage capacitor C1 for initializing the voltages of the control terminal of the driving transistor M3 and the second terminal of the storage capacitor C1, and 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 terminal of the storage capacitor C1 for initializing the voltages of the anode of the light-emitting device D1 and the first terminal of the storage capacitor C1, where the voltage stored in the storage capacitor C1 is Vc1= Vref1-Vref2; in the threshold voltage compensation stage T2, under the control of the scan signal S2, the data writing transistor M2 and the threshold compensation transistor M4 are turned on, the turned-on data writing transistor M2 provides the data voltage Vdata to the second path terminal of the driving transistor M3, the turned-on threshold compensation transistor M4 short-circuits the control terminal of the driving transistor M3 and the first path terminal to make the driving transistor M3 form a diode electrical connection structure, and the charge stored in the storage capacitor C1 passes through the turned-on driving transistor M3 and the threshold compensation transistor M4The compensation transistor M4 discharges until the voltage at the control end of the driving transistor M3 is Vg = Vdata + Vth, and the voltage stored in the storage capacitor C1 at this time is Vc1= Vdata + Vth; in the light emitting period T3, under the control of the light emitting control signal vector, the first light emitting control transistor M1 and the second light emitting control transistor M6 are both turned on, the turned-on first light emitting control transistor M1 provides the power voltage VDD to the first path terminal of the driving transistor M3, the voltage stored in the storage capacitor C1 is applied to the control terminal of the driving transistor M3, the driving transistor M3 is turned on, and the turned-on light emitting control transistor M6 turns on the second path terminal of the driving 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 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 is operated in a saturation state, and the light emitting current I flowing through the light emitting device D1 is: i = k (Vgs-Vth) 2 ＝k(Vdata) 2 Where k is a constant related to the material and size of the drive transistor M3. Therefore, the light-emitting current of the pixel circuit flowing through the light-emitting device D1 is irrelevant to the threshold voltage of the driving transistor M3, 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. The simulation data of the pixel light emission current change when the threshold voltage of the driving transistor of the 7T1C pixel circuit shown in fig. 1 drifts is shown in fig. 3, and it can be proved by simulation results that the compensation effect of the above scheme still needs to be improved, and when the threshold voltage of the driving TFT drifts by 2V, the light emission current of the Micro-LED is reduced by about 20%, which may cause the light emission current of each pixel to be uneven in size, thereby causing the phenomenon of uneven display screen.
The existing 7T1C pixel circuit adopts 7 TFTs and 6 driving waveforms, and the circuit structure is relatively complex. Since the pixel area of a high-resolution screen is generally small, the complicated circuit structure causes the areas of the storage capacitor and the driving transistor to be limited, and the compensation effect of the threshold voltage drift is not ideal.
Therefore, there is a need to provide an improved technical solution to further improve the compensation effect of the threshold voltage drift.
Disclosure of Invention
In view of the foregoing, an object of the present invention 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 threshold voltage drift.
The invention provides a miniature light-emitting diode pixel circuit, which comprises an initialization module, a threshold voltage compensation module and a load driving module, wherein the initialization module is used for initializing the pixel circuit; the initialization module is connected with the threshold voltage compensation module and the load driving module, and is 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 and used for receiving scanning signals and data voltages and compensating the threshold voltage of the load driving module through the data voltages under the control of the scanning signals so as to obtain driving voltages for driving light emitting devices of the load driving module; the load driving module is connected with the threshold voltage compensation module and 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.
Preferably, 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.
Preferably, the threshold voltage compensation module comprises a storage capacitor, a threshold compensation transistor and a data writing transistor; a first end of the storage capacitor is electrically connected with a first path end of the initialization transistor and the load driving module, and a second end of the storage capacitor is electrically connected with a first path end of the threshold compensation transistor and the load driving module; the control end of the threshold compensation transistor is used for receiving the scanning signal, the first path end of the threshold compensation transistor is electrically connected with the load driving module, and the second path 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 used for receiving the scanning signal, the first path end of the data writing transistor is used for receiving the data voltage, and the second path end of the data writing transistor is electrically connected with the load driving module.
Preferably, the load driving module includes a stabilization transistor, a driving transistor, a light emission control transistor, and a light emitting device; the control end of the stabilizing transistor is used for receiving a stabilizing control signal, the first path end of the stabilizing transistor is used for receiving the power supply voltage, and the second path end of the stabilizing transistor is electrically connected with the first path end of the driving transistor and the second path end of the threshold compensating transistor; the control end of the driving transistor is electrically connected with the first path end of the threshold compensation transistor and the second end of the storage capacitor, the first path end of the driving transistor is also electrically connected with the second path end of the threshold compensation transistor, and the second path end of the driving transistor is electrically connected with the first path end of the light-emitting control transistor and the second path end of the data writing transistor; the control end of the light-emitting control transistor is used for receiving the light-emitting control signal, and the second path end of the light-emitting control transistor is electrically connected with the anode of the light-emitting device; the cathode of the light emitting device is electrically connected with a ground terminal.
The invention also provides a driving method of the micro light-emitting diode pixel circuit, which is applied to the micro light-emitting diode pixel circuit and comprises the following steps:
s01, controlling the initialization module to initialize the threshold voltage compensation module and the load driving module, and controlling the threshold voltage compensation module to receive data voltage and compensate the threshold voltage of the load driving module to obtain a driving voltage for driving a light emitting device of the load driving module;
s02, controlling the threshold voltage compensation module to continuously receive the data voltage and performing threshold voltage compensation on the load driving module;
and S03, controlling the load driving module to convert the driving voltage into a light-emitting current so that a light-emitting device of the load driving module emits light.
Preferably, the step S01 further includes: the initialization transistor is controlled to be switched on by the initialization signal, the stabilization transistor is controlled to be switched on by the stabilization control signal, the data writing transistor and the threshold compensation transistor are controlled to be switched on by the scanning signal, the driving transistor forms a diode electric connection structure, and the light-emitting control transistor is controlled to be switched off by the light-emitting control signal.
Preferably, the step S02 further includes: and controlling the data writing transistor and the threshold compensation transistor to be continuously switched on through the scanning signal, enabling the driving transistor to continuously form a diode electric connection structure, controlling the stabilizing transistor to be switched off through the stabilizing control signal, controlling the light-emitting control transistor to be continuously switched off through the light-emitting control signal, and controlling the initialization transistor to be switched off through the initialization signal.
Preferably, the step S03 further includes: the stable transistor is controlled to be switched on by the stable control signal, the driving transistor is controlled to be switched on by the driving voltage, the light-emitting control transistor is controlled to be switched on by the light-emitting control signal, the data writing transistor and the threshold compensation transistor are controlled to be switched off by the scanning signal, and the initialization transistor is controlled to be switched off by the initialization signal.
Preferably, a current flowing through the light emitting device in the step S01 is smaller than a light emitting current flowing through the light emitting device in the step S03.
The invention also provides a display device which comprises the micro light-emitting diode pixel circuit.
Compared with the prior art, the micro light-emitting diode pixel circuit and the display device provided by the invention comprise a stabilizing transistor, a data writing transistor, a driving transistor, a threshold compensation transistor, a light-emitting control transistor, an initialization transistor, a storage capacitor and a light-emitting device. The selective conduction of the six transistors is realized through the three time sequence stages of the initialization stage, the threshold voltage compensation stage and the light-emitting stage, and the threshold voltage is compensated by combining the storage capacitor, so that one transistor is saved, the circuit is simplified, and the compensation effect on the threshold voltage drift of the driving transistor is further improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a circuit diagram of a conventional 7T1C pixel circuit;
fig. 2 is a timing diagram of a conventional 7T1C pixel circuit;
FIG. 3 is a schematic diagram of simulation data of a pixel light emission current variation when a threshold voltage of a driving transistor of a 7T1C pixel circuit shifts according to the prior art;
FIG. 4 is a circuit diagram of a micro LED pixel circuit according to an embodiment of the present invention;
FIG. 5 is a timing diagram of a micro light emitting diode pixel circuit according to an embodiment of the present invention;
fig. 6 is a simulation comparison diagram of the threshold voltage offset compensation effect of the micro led pixel circuit according to an embodiment of the invention and the conventional 7T1C pixel circuit.
Detailed Description
The foregoing and other aspects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments, as illustrated in the accompanying drawings. While the invention has been described in connection with specific embodiments thereof, it is to be understood that both the foregoing general description and the following detailed description are intended to provide further explanation of the invention as claimed, and that the invention is not limited to the specific embodiments shown. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.
An embodiment of the invention provides a micro led pixel circuit, as shown in fig. 4, the micro led pixel circuit includes an initialization module 110, a threshold voltage compensation module 120, and a load driving module 130.
The initialization module 110 is connected to the threshold voltage compensation module 120 and the load driving module 130, and configured to receive an initialization signal S1 and a reference voltage Vref2, and initialize the threshold voltage compensation module 120 and the load driving module 130 through the reference voltage Vref2 under the control of the initialization signal S1; the threshold voltage compensation module 120 is connected to the load driving module 130, and is configured to receive the scan signal S2 and the data voltage Vdata, and compensate the threshold voltage of the load driving module 130 through the data voltage Vdata under the control of the scan signal S2, so as to obtain a driving voltage for driving the light emitting device D1 of the load driving module 130; the load driving module 130 is connected to the threshold voltage compensation module 120, and is configured to receive the light-emitting control signal veimit, the stable control signal S3, and the power voltage VDD, and convert 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 stable control signal S3 and the light-emitting control signal veimit.
Specifically, the initialization signal S1, the stabilization control signal S3, the scan signal S2, and the light emission control signal veimit are all provided by an external timing controller.
Specifically, the initialization module 110 includes an initialization transistor M7; the control terminal of the initialization transistor M7 is configured to receive the initialization signal S1, the first path terminal of the initialization transistor M7 is electrically connected to the threshold voltage compensation module 120 and the load driving module 130, and the second path terminal of the initialization transistor M7 is configured to receive the reference voltage Vref2.
Specifically, the threshold voltage compensation module 120 includes a storage capacitor C1, a threshold compensation transistor M4, and a data write transistor M2; a first end of the storage capacitor C1 is electrically connected to the first path end of the initialization transistor M7 and the load driving module 130, and a second end of the storage capacitor C1 is electrically connected to the first path end of the threshold compensation transistor M4 and the load driving module 130; a control end of the threshold compensation transistor M4 is configured to receive the scan signal S2, a first path end of the threshold compensation transistor M4 is electrically connected to the load driving module 130, and a second path end of the threshold compensation transistor M4 is also electrically connected to the load driving module 130; the control terminal of the data writing transistor M2 is also configured to receive the scan signal S2, the first path terminal of the data writing transistor M2 is configured to receive the data voltage Vdata, and the second path terminal of the data writing transistor M2 is electrically connected to the load driving module 130.
Specifically, the load driving module 130 includes a stabilization transistor M1, a driving transistor M3, a light emission control transistor M6, and a light emitting device D1; the control end of the stabilizing transistor M1 is used for receiving a stabilizing control signal S3, the first path end of the stabilizing transistor M1 is used for receiving a power supply voltage VDD, and the second path end of the stabilizing transistor M1 is electrically connected with the first path end of the driving transistor M3 and the second path end of the threshold compensation transistor M4; the control end of the driving transistor M3 is electrically connected with the first path end of the threshold compensation transistor M4 and the second end of the storage capacitor C1, the first path end of the driving transistor M3 is also electrically connected with the second path end of the threshold compensation transistor M4, and the second path end of the driving transistor M3 is electrically connected with the first path end of the light-emitting control transistor M6 and the second path end of the data writing transistor M2; the control end of the light-emitting control transistor M6 is used for receiving the light-emitting control signal veimit, and the second path end of the light-emitting control transistor M6 is electrically connected with the anode of the light-emitting device D1; the cathode of the light emitting device D1 is electrically connected to the ground terminal.
In some embodiments of the present invention, the light emitting device D1 may be a light emitting diode LED, an organic light emitting diode OLED, a Micro-LED, a Mini-LED, an inorganic light emitting diode QLED, or the like.
Each of the transistors is an N-type transistor; the circuit connection can be slightly changed based on the same principle, and the method can also be applied to a P-type transistor. In addition, the control end of each transistor is a gate, the first path end may be a source, and the second path end may be a drain; or the first path end is a drain electrode, and the second path end is a source electrode.
Another embodiment of the present invention further provides a driving method of a micro light emitting diode pixel circuit, which is applied to the above-mentioned micro light emitting diode pixel circuit;
as shown in fig. 4, the micro led pixel circuit includes an initialization transistor M7 of the initialization module 110, a storage capacitor C1, a threshold compensation transistor M4, and a data writing transistor M2 of the threshold voltage compensation module 120, a stabilization transistor M1, a driving transistor M3, a light emitting control transistor M6, and a light emitting device D1 of the load driving module 130. The driving method includes:
s01, controlling the initialization module 110 to initialize the threshold voltage compensation module 120 and the load driving module 130, and controlling 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 a driving voltage for driving the light emitting device D1 of the load driving module 130;
s02, controlling the threshold voltage compensation module 120 to continue receiving the data voltage Vdata and performing threshold voltage compensation on the load driving module 130;
s03, the load driving module 130 is controlled to convert the driving voltage into a light emitting current, so that the light emitting device D1 of the load driving module 130 emits light.
In an embodiment of the invention, as shown in fig. 5, the combination of the initialization signal S1, the stable control signal S3, the scan signal S2, and the light-emitting control signal veimit sequentially corresponds to an initialization stage, a threshold voltage compensation stage, and a light-emitting stage. The micro led pixel circuit shown in fig. 4 and the driving method thereof will be described in detail with reference to the timing signal diagram shown in fig. 5 by taking the above transistors as N-type transistors as an example.
In the initialization stage T1, the initialization signal S1 is a high level signal, and controls the initialization transistor M7 to be in a conducting state; the scanning signal S2 is also a high level signal, and controls both the data writing transistor M2 and the threshold compensation transistor M4 to be in a conducting state; the stabilization control signal S3 is also a high level signal, and controls the stabilization transistor M1 to be in a conducting state. The emission control signal veimit is a low level signal, and controls the emission control transistor M6 to be in an off state.
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 end of the storage capacitor C1, so as to initialize the anode of the light emitting device D1 and alleviate the aging of the light emitting device D1, where it should be noted that at this time, the current flowing through the light emitting device D1 is small, and the light emitting device D1 does not emit light. The voltage at the first end of the storage capacitor C1 is also initialized, so as to avoid the influence of the signal of the previous image frame remaining in the storage capacitor C1 on the display picture of the image frame. The turned-on stabilizing transistor M1 supplies the power supply voltage VDD to the first path terminal of the driving transistor M3, so that the voltage Vd = Vnet5= VDD of the fifth node NET5, i.e., the first path terminal of the driving transistor M3. The turned-on threshold compensation transistor M4 in turn provides the power voltage VDD to the control terminal of the driving transistor M3, so that the voltage Vg = Vnet1= VDD at the first node NET1, i.e., the control terminal of the driving transistor M3, and the voltage Vc1= VDD-Vref2 at the two ends of the storage capacitor C1. The turned-on data writing transistor M2 provides the data voltage Vdata to the second path end of the driving transistor M3, and the turned-on threshold compensation transistor M4 short-circuits the control end of the driving transistor M3 and the first path end, so that the driving transistor M3 forms a diode electrical connection structure, and thus the driving transistor M3 is also in a turned-on state. The data voltage Vdata is lower than the voltage VDD at the second end of the storage capacitor C1. Therefore, the electric charge stored in the storage capacitor C1 is discharged by the driving transistor M3 that is turned on, so that the potential of the first node NET1 is continuously decreased, and when the voltage Vgs-Vth =0 between the control terminal of the driving transistor M3 and the second path terminal, vth is the threshold voltage of the driving transistor M3, the driving transistor M3 is turned off, and the storage capacitor C1 stops discharging. At this time, the voltage at the control terminal of the driving transistor M3 is Vg = Vnet1= Vdata + Vth. The voltage stored in the storage capacitor C1 at this time is Vc1= Vdata + Vth-Vref2.
In the threshold voltage compensation stage T2, the scan signal S2 is still a high level signal, and the data writing transistor M2 and the threshold compensation transistor M4 are still controlled to be in a conducting state. The initialization signal S1 is a low level signal and controls the initialization transistor M7 to be in a cut-off state; the stabilization control signal S3 is a low level signal, and controls the stabilization transistor M1 to be in an off state, and the light emission control signal veimit is still a low level signal, and controls the light emission control transistor M6 to be in an off state.
In the threshold voltage compensation stage T2, the turned-on data writing transistor M2 continues to provide the data voltage Vdata to the second path end of the driving transistor M3, and the turned-on threshold compensation transistor M4 continues to short-circuit the control end of the driving transistor M3 and the first path end, so that the driving transistor M3 forms a diode electrical connection structure, and the driving transistor M3 is in a turned-on state. At this time, the voltage at the second end of the storage capacitor C1 is still greater than the data voltage Vdata, so that the charge stored in the storage capacitor C1 continues to be discharged through the turned-on driving transistor M3 and the turned-on threshold compensation transistor M4, so that the voltage at the first node NET1 becomes Vdata + Vth. At this time, the voltage at the control terminal of the driving transistor M3 is Vg = Vnet1= Vdata + Vth, and the voltage stored in the storage capacitor C1 is Vc1= Vdata + Vth.
In the light-emitting period T3, the stabilization control signal S3 is a high level signal, which controls the stabilization transistor M1 to be in a conducting state, and the light-emitting control signal veimit is a high level signal, which controls the light-emitting control transistor M6 to be in a conducting state. The scanning signal S2 is a low level signal, which controls both the data writing transistor M2 and the threshold compensation transistor M4 to be in an off state, and the initialization signal S1 is still a low level signal, which controls the initialization transistor M7 to be in an off state.
In the light emitting period T3, the turned-on light emitting control transistor M6 supplies the power voltage VDD to the first path terminal of the driving transistor M3, the storage capacitor C1 is connected to both the control terminal of the driving transistor M3 and a second path terminal (e.g., source), the voltage stored in the storage capacitor C1 is applied to the control terminal of the driving transistor M3 to turn on the driving transistor M3, and the turned-on light emitting controlThe transistor M6 turns on the second path terminal of the driving transistor M3 with the anode of the light emitting device D1. In this case, the voltage of the control terminal and the second path terminal 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 turned-on stabilizing transistor M1 supplies the power supply voltage VDD to the first path terminal of the driving transistor M3, so that the driving transistor M3 operates in a saturation state. In this case, the current path between the power 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) 2 Where k is a constant related to the material and size of the drive transistor M3. Therefore, the light-emitting current of the micro light-emitting diode pixel circuit flowing through the light-emitting device D1 is irrelevant to the threshold voltage of the driving transistor M3, so that 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.
The absolute voltage values of the high-level signal and the low-level signal may be equal or unequal. For example, the high level is a value greater than 0, the low level is 0V, or the high level is 0V, and the low level is a value less than 0, which is determined by design according to actual requirements in practical applications, and is not limited herein.
The micro light-emitting diode pixel circuit provided by the invention enables the power supply voltage VDD to replace the first reference voltage Vref1 in the 7T1C pixel circuit in the prior art in the initialization stage T1 through the new stable control signal S3, thereby saving one transistor, namely the first initialization transistor M5 in the 7T1C pixel circuit. And the data voltage Vdata is written into the second path end of the driving transistor M3 in the initialization stage T1, so that the compensation time of the threshold voltage is increased, and the compensation effect is further improved. As shown in fig. 6, which is a simulation comparison diagram of the pixel circuit in the embodiment of the present invention and the above-mentioned conventional 7T1C pixel circuit for the threshold voltage offset compensation effect, compared with the conventional 7T1C pixel circuit, the micro light emitting diode pixel circuit provided by the present invention 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 for increasing the channel width of the storage capacitor and the driving transistor, thereby further strengthening the compensation effect.
In the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed," "mounted," "connected," and the like are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms can be understood in a specific case to those of ordinary skill in the art. The terms "first," "second," and the like, are used solely to distinguish between similar elements and not to indicate or imply relative importance or a particular order. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, including not only those elements listed, but also other elements not expressly listed.
The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (10)
1. A micro light emitting diode pixel circuit is characterized by 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, and is 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 and used for receiving scanning signals and data voltages and compensating the threshold voltage of the load driving module through the data voltages under the control of the scanning signals so as to obtain driving voltages for driving light emitting devices of the load driving module;
the load driving module is 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.
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 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 path end of the initialization transistor and the load driving module, and a second end of the storage capacitor is electrically connected with a first path end of the threshold compensation transistor and the load driving module;
the control end of the threshold compensation transistor is used for receiving the scanning signal, the first path end of the threshold compensation transistor is electrically connected with the load driving module, and the second path 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 used for receiving the scanning signal, the first path end of the data writing transistor is used for receiving the data voltage, and the second path end of the data writing transistor is electrically connected with the load driving module.
4. The micro light-emitting diode pixel circuit according to claim 3, wherein the load driving module comprises a stabilization transistor, a driving transistor, a light emission control transistor, and a light-emitting device;
the control end of the stabilizing transistor is used for receiving a stabilizing control signal, the first path end of the stabilizing transistor is used for receiving the power supply voltage, and the second path end of the stabilizing transistor is electrically connected with the first path end of the driving transistor and the second path end of the threshold compensating transistor;
the control end of the driving transistor is electrically connected with the first path end of the threshold compensation transistor and the second end of the storage capacitor, the first path end of the driving transistor is also electrically connected with the second path end of the threshold compensation transistor, and the second path end of the driving transistor is electrically connected with the first path end of the light-emitting control transistor and the second path end of the data writing transistor;
the control end of the light-emitting control transistor is used for receiving the light-emitting control signal, and the second path end of the light-emitting control transistor is electrically connected with the anode of the light-emitting device;
the cathode of the light emitting device is electrically connected with a ground terminal.
5. A driving method of a micro light emitting diode pixel circuit is applied to the micro light emitting diode pixel circuit as claimed in any one of claims 1 to 4, wherein;
s01, controlling the initialization module to initialize the threshold voltage compensation module and the load driving module, and controlling the threshold voltage compensation module to receive data voltage and compensate the threshold voltage of the load driving module to obtain a driving voltage for driving a light emitting device of the load driving module;
s02, controlling the threshold voltage compensation module to continuously receive the data voltage and performing threshold voltage compensation on the load driving module;
and S03, controlling the load driving module to convert the driving voltage into a light-emitting current so that a light-emitting device of the load driving module emits light.
6. The method for driving a pixel circuit of a micro light emitting diode according to claim 5, wherein the step S01 further comprises: the initialization transistor is controlled to be switched on by the initialization signal, the stabilization transistor is controlled to be switched on by the stabilization control signal, the data writing transistor and the threshold compensation transistor are controlled to be switched on by the scanning signal, the driving transistor forms a diode electric connection structure, and the light-emitting control transistor is controlled to be switched off by the light-emitting control signal.
7. The method for driving a pixel circuit of a micro light emitting diode according to claim 5, wherein the step S02 further comprises: and controlling the data writing transistor and the threshold compensation transistor to be continuously switched on through the scanning signal, enabling the driving transistor to continuously form a diode electric connection structure, controlling the stable transistor to be switched off through the stable control signal, controlling the light-emitting control transistor to be continuously switched off through the light-emitting control signal, and controlling the initialization transistor to be switched off through the initialization signal.
8. The method for driving a pixel circuit of a micro light emitting diode according to claim 5, wherein the step S03 further comprises: the stable transistor is controlled to be switched on by the stable control signal, the driving transistor is controlled to be switched on by the driving voltage, the light-emitting control transistor is controlled to be switched on by the light-emitting control signal, the data writing transistor and the threshold compensation transistor are controlled to be switched off by the scanning signal, and the initialization transistor is controlled to be switched off by the initialization signal.
9. The method of driving a micro light-emitting diode pixel circuit according to claim 5, wherein a current flowing through the light-emitting device in the step S01 is smaller than a light-emitting current flowing through the light-emitting device in the step S03.
10. A display device comprising the micro light-emitting diode pixel circuit according to any one of claims 1 to 4.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211490892.9A CN115775524A (en) | 2022-11-25 | 2022-11-25 | Micro light-emitting diode pixel circuit and driving method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211490892.9A CN115775524A (en) | 2022-11-25 | 2022-11-25 | Micro light-emitting diode pixel circuit and driving method |
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| CN202211490892.9A Pending CN115775524A (en) | 2022-11-25 | 2022-11-25 | Micro light-emitting diode pixel circuit and driving method |
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| CN (1) | CN115775524A (en) |
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