The present application relates to display technologies, and more particularly, to a pixel circuit and a display panel.
The driving methods of display technology include pulse amplitude modulation (PAM), pulse width modulation (PWM) and a mixture of the two. The PWM driving method has the advantages of constant current, high luminous efficiency, and low grayscale display quality. Therefore, PWM or PWM-based hybrid driving methods have been extensively studied.
The pixel circuit shown in
As shown in
The pixel circuit shown in
As shown in
At the same time, due to differences in the threshold voltage of the transistor T4 in different pixel circuits, in order to display uniformity, a more complicated circuit structure is needed to compensate the threshold voltage of the transistor T4.
It should be noted that the above-mentioned introduction of the background technology is only for a purpose of facilitating a clear and complete understanding of the technical solutions of the present application. Therefore, it cannot be considered that the above-mentioned technical solutions involved are known to those skilled in the art just because it appears in the background art of the present application.
The present application provides a pixel circuit and a display panel to improve a control accuracy of the light-emitting time in a pulse width driving mode.
In a first aspect, the present application provides a pixel circuit, which includes a driving transistor T2 and a pulse width driving module; and the pulse width driving module electrically connected to a gate electrode of the driving transistor T2, wherein the pulse width driving module includes a display time control unit, an electrical potential modulation unit, and a Schmitt trigger; wherein one terminal of the display time control unit is electrically connected to the gate electrode of the driving transistor T2, and wherein another terminal of the display time control unit is configured to receive a first reference signal and is configure to turn off the driving transistor T2; and wherein an input terminal of the Schmitt trigger is electrically connected to the output terminal of the electrical potential modulation unit, and wherein an output terminal of the Schmitt trigger is electrically connected to a control terminal of the display time control unit.
In some of the embodiments, the Schmitt trigger includes an inverter INV1, an inverter INV2, and a resistor R2. An input terminal of the inverter INV1 is electrically connected to the output terminal of the electrical potential modulation unit; wherein an input terminal of the inverter INV2 is electrically connected to an output terminal of the inverter INV1, and wherein the output terminal of the inverter INV2 is electrically connected to the control terminal of the display time control unit; and one terminal of the resistor R2 is electrically connected to the input terminal of the inverter INV1, and another terminal of the resistor R2 is electrically connected to the output terminal of the inverter INV2.
In some of the embodiments, the Schmitt trigger further includes a resistor R1, wherein one terminal of the resistor R1 is electrically connected to the output terminal of the electrical potential modulation unit, and wherein another terminal of the resistor R1 is electrically connected to the input terminal of the inverter INV1.
In some of the embodiments, the inverter INV1 comprises a transistor M1 and a transistor M2; wherein one of a source electrode and a drain electrode of the transistor M1 is electrically connected to a gate electrode of the transistor M1, and is configured to receive a high electrical potential signal; and wherein one of a source electrode and a drain electrode of the transistor M2 is electrically connected to another one of the source electrode and the drain electrode of the transistor M1 and the input terminal of the inverter INV2, and wherein a gate electrode is electrically connected to the output terminal of the electrical potential modulation unit, and another one of the source electrode and the drain electrode of the transistor M2 is configured to receive a first reference signal.
In some of the embodiments, the inverter INV2 includes a transistor M3 and a transistor M4, wherein one of a source electrode and a drain electrode of the transistor M3 is electrically connected to a gate electrode of the transistor M3, and is configured to receive the high electrical potential signal; and wherein one of a source electrode and a drain electrode of the transistor M4 is electrically connected to another one of the source electrode and the drain electrode of the transistor M3 and the control terminal of the display time control unit, and wherein a gate electrode of the transistor M4 is electrically connected to one of the source electrode and the drain electrode of the transistor M2, and wherein another one of the source electrode and the drain electrode of the transistor M4 is configured to receive the first reference signal.
In some of the embodiments, the display time control unit comprises a transistor T4, and one of a source electrode and a drain electrode of the transistor T4 is electrically connected to the gate electrode of the driving transistor T2, and wherein another one of the source electrode and the drain electrode of the transistor T4 is configured to access the first reference signal, and wherein a gate electrode of the transistor T4 is electrically connected to the output terminal of the Schmitt trigger.
In some of the embodiments, the potential modulation unit comprises a capacitor C2, one terminal of the capacitor C2 is electrically connected to the input terminal of the Schmitt trigger, and another terminal of the capacitor C2 is configured to receive a triangle wave control signal.
In some of the embodiments, the potential modulation unit further comprises a transistor T5, and wherein one of a source electrode and a drain electrode of the transistor T5 is configured to receive an electrical potential setting signal, and a gate electrode of transistor T5 is configured to receive a pulse width control signal.
In some of the embodiments, the pixel circuit further includes a transistor T1, a transistor T3, a capacitor C1, and a light-emitting device D1; wherein one of a source electrode and a drain electrode of the transistor T1 is configured to receive a data signal, and wherein a gate electrode of the transistor T1 is configured to receive a pulse amplitude control signal, and wherein another one of the source electrode and the drain electrode of the transistor T1 is electrically connected to the gate electrode of the driving transistor T2; wherein one of a source electrode and a drain electrode of the transistor T3 is configured to receive the second reference signal, and wherein the gate electrode of the transistor T3 is configured to receive the pulse amplitude control signal, and wherein another one of the source electrode and the drain electrode of the transistor T3 is electrically connected to the source electrode of the driving transistor T2; wherein one terminal of the capacitor C1 is electrically connected to the gate electrode of the driving transistor T2, and another terminal of the capacitor C1 is electrically connected to the source electrode of the driving transistor T2; and wherein an anode of the light-emitting device D1 is electrically connected to the source electrode of the driving transistor T2, and wherein a cathode of the light-emitting device D1 is configured to connect a negative power supply signal; wherein the drain electrode of the driving transistor T2 is configured to receive a positive power supply signal.
In a second aspect, the present application provides a display panel, which includes the pixel circuit in at least one of the above embodiments, the pixel circuit further includes a light-emitting chip, and wherein the Schmitt trigger is integrated in the light-emitting chip.
The pixel circuit and the display panel provided by the present application, by connecting the Schmitt trigger in series between the output terminal of the potential modulation unit and the control terminal of the display time control unit, can more quickly turn on the display time control unit to turn off the driving transistor T2, in turn, can more accurately control the display time or light-emitting time of the pixel circuit.
The following detailed description of the specific implementations of the present application in conjunction with the accompanying figures will make the technical solutions and other beneficial effects of the present application obvious.
The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the figures in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without inventive steps shall fall within a protection scope of the present application.
In view of the above-mentioned technical problem that it is difficult to accurately control the light-emitting time in a pulse width driving mode, this embodiment provides a pixel circuit. Please refer to
It is understandable that the pixel circuit provided in this embodiment can turn on the display time control unit 10 and turn off the driving transistor T2 more quickly by connecting the Schmitt trigger 20 in series between the output terminal of the electrical potential modulation unit 30 and the control terminal of the display time control unit 10, to more accurately control the display time or light-emitting time of the pixel circuit.
In one of the embodiments, the display time control unit 10 includes a transistor T4. One of a source electrode and a drain electrode of the transistor T4 is electrically connected to the gate electrode of the driving transistor T2. Another one of the source electrode and the drain electrode of the transistor T4 is configured to receive the first reference signal Vneg. The gate electrode of the transistor T4 is electrically connected to the output terminal of the Schmitt trigger 20.
In one of the embodiments, the electrical potential modulation unit 30 includes a capacitor C2, one terminal of the capacitor C2 is electrically connected to the input terminal of the Schmitt trigger 20, and another terminal of the capacitor C2 is configured to receive the triangular wave control signal Sweep.
In one of the embodiments, the electrical potential modulation unit 30 further includes a transistor T5. One of a source electrode and a drain electrode of the transistor T5 is configured to receive an electrical potential setting signal, and a gate electrode of the transistor T5 is configured to receive the pulse width control signal SPWM. The electrical potential setting signal may be, but not limited to, data signal Data, and may also be other signals with suitable electrical potential.
As shown in
In one of the embodiments, as shown in
It is understandable that, in this embodiment, since positive feedback is formed between the input terminal of the inverter INV1 and the output terminal of the inverter INV2 through the resistor T2, an electrical potential at point B can rise at a faster rate, to turn on the transistor T4 with a more precise time.
In one of the embodiments, the Schmitt trigger 20 further includes a resistor R1. One terminal of the resistor R1 is electrically connected to an output terminal of the electrical potential modulation unit 30, and another terminal of the resistor R1 is electrically connected to the input terminal of the inverter INV1.
It should be noted that the resistor R1 can be adapted to the electrical potential of point C, to make the inverter INV1 can be configured to receive different electrical potentials of point C.
It takes a certain time for a single inverter to switch states. When the Schmitt trigger 20 switches between states, there is a positive feedback process: an electrical potential VA at point A increased, an electrical potential VC at point C also increased accordingly, an electrical potential VM at point M decreased accordingly, an electrical potential VB at point B increased accordingly, and an electrical potential VC at point C also increased accordingly. Due to the above-mentioned positive feedback process, the electrical potential VB at the point B can change rapidly, to make the waveform of the electrical potential VB at the point B is infinitely close to a square wave, so that light-emitting time of the pixel circuit can be controlled more accurately.
In one of the embodiments, as shown in
The high electrical potential signal may be a power positive signal VDD. The first reference signal Vneg may also be a power negative signal VSS.
In one of the embodiments, as shown in
As shown in
Compared with
At the same time, due to the Schmitt trigger 20 with high hysteresis characteristics is disposed in the pixel circuit shown in
With this display function, different initial electrical potentials can be provided to point A, so that different display times can be correspondingly obtained, and high-precision gray-scale segmentation can be achieved without the need for particularly high-frequency signals.
As shown in
It is understandable that the display panel provided in this embodiment can turn on control unit 10 more quickly to turn off the driving transistor T2 by connecting the Schmitt trigger 20 in series between an output terminal of the electrical potential modulation unit 30 and a control terminal of the display time control unit 10, to more accurately control display time or light-emitting time of the pixel circuit.
It should be noted that the light-emitting chip 200 may be a Mini-LED chip or a Micro-LED chip. As shown in
In the above-mentioned embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in an embodiment, reference may be made to related descriptions of other embodiments.
The pixel circuits and display panels provided by the embodiments of the application are described in detail above. Specific examples are used in this article to describe the principles and implementations of the present application. The descriptions of the above embodiments are only used to help understand the technical solution and core idea of the present application. Those of ordinary skill in the art should understand that: It is possible to modify the technical solutions recorded in the foregoing embodiments, or equivalently replace some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions deviates from the scope of the technical solutions of the embodiments of the present application.
Number | Date | Country | Kind |
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202111521974.0 | Dec 2021 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2021/139318 | 12/17/2021 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2023/108650 | 6/22/2023 | WO | A |
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Number | Date | Country | |
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20240029623 A1 | Jan 2024 | US |