The present application claims priority to Chinese Patent Application No. 201910209387.4, filed on Mar. 19, 2019, the disclosure of which is incorporated herein by reference in its entirety as part of the present application.
Embodiments of the present disclosure relate to a pixel circuit and a driving method thereof, a display panel, and a display device.
With the development and progress of technology, people have higher and higher requirements for the display quality of display devices. In display devices, pixel circuits are usually used to drive pixel units to emit light. In the pixel circuit, a driving transistor is usually turned on by a data signal stored in a storage capacitor, and a light-emitting control transistor is controlled to be turned on by a light-emitting control signal, so that a light-emitting element is driven by a power signal to emit light.
At least one embodiment of the present disclosure provides a pixel circuit, which includes: a driving circuit, a first switching circuit, a second switching circuit, and a first reset circuit. The driving circuit includes a first terminal, a second terminal, and a control terminal, and is configured to drive a light-emitting element connected to the second terminal to emit light. The first switching circuit is configured to be turned on in response to a first scanning signal to transmit a data signal to the control terminal of the driving circuit. The second switching circuit is connected to the first terminal of the driving circuit and is configured to be turned on in response to a light-emitting control signal to transmit a first power signal to the first terminal of the driving circuit. The first reset circuit is connected to the first terminal of the driving circuit and is configured to be turned on in response to a first reset control signal to transmit a reset signal to the first terminal of the driving circuit.
For example, the pixel circuit provided by at least one embodiment of the present disclosure further includes a third switching circuit. The third switching circuit includes a complementary metal oxide semiconductor circuit. The third switching circuit includes a first terminal, a second terminal, a first control terminal, and a second control terminal. The first terminal of the third switching circuit is connected to the first switching circuit, and the second terminal of the third switching circuit is connected to the control terminal of the driving circuit. The first control terminal is connected to a first scanning signal input terminal to receive the first scanning signal, and the third switching circuit is configured to be turned on in response to the first scanning signal to transmit the data signal from the first switching circuit to the control terminal of the driving circuit. The second control terminal is connected to a second scanning signal input terminal to receive a second scanning signal, and the third switching circuit is further configured to be turned on in response to the second scanning signal to transmit the data signal from the first switching circuit to the control terminal of the driving circuit.
For example, in the pixel circuit provided by at least one embodiment of the present disclosure, the first scanning signal and the second scanning signal are synchronized, and a trigger level of the first scanning signal is opposite to a trigger level of the second scanning signal.
For example, the pixel circuit provided by at least one embodiment of the present disclosure further includes: a second reset circuit, connected to a first terminal of the light-emitting element and configured to be turned on in response to a second reset control signal to transmit the reset signal to the first terminal of the light-emitting element.
For example, in the pixel circuit provided by at least one embodiment of the present disclosure, the first reset control signal and the second reset control signal are a same reset control signal.
For example, in the pixel circuit provided by at least one embodiment of the present disclosure, the driving circuit includes a driving transistor, a first electrode of the driving transistor serves as the first terminal of the driving circuit, a gate electrode of the driving transistor serves as the control terminal of the driving circuit, and a second electrode of the driving transistor serves as the second terminal of the driving circuit.
For example, in the pixel circuit provided by at least one embodiment of the present disclosure, the first switching circuit includes a first transistor, a first electrode of the first transistor is connected to a data signal input terminal to receive the data signal, a second electrode of the first transistor is connected to the first terminal of the third switching circuit, and a gate electrode of the first transistor is connected to a first scanning signal input terminal to receive the first scanning signal.
For example, in the pixel circuit provided by at least one embodiment of the present disclosure, the second switching circuit includes a second transistor, a first electrode of the second transistor is connected to a first power signal input terminal to receive the first power signal, a second electrode of the second transistor is connected to the first terminal of the driving circuit, and a gate electrode of the second transistor is connected to a light-emitting control signal input terminal to receive the light-emitting control signal.
For example, in the pixel circuit provided by at least one embodiment of the present disclosure, the first reset circuit includes a third transistor, a first electrode of the third transistor is connected to a reset signal input terminal to receive the reset signal, a second electrode of the third transistor is connected to the first terminal of the driving circuit, and a gate electrode of the third transistor is connected to a first reset control signal input terminal to receive the first reset control signal.
For example, in the pixel circuit provided by at least one embodiment of the present disclosure, the third switching circuit includes a fifth transistor and a sixth transistor. A first electrode of the fifth transistor is connected to the first switching circuit, a second electrode of the fifth transistor is connected to the control terminal of the driving circuit, and a gate electrode of the fifth transistor is connected to a first scanning signal input terminal to receive the first scanning signal. A first electrode of the sixth transistor is connected to the first switching circuit, a second electrode of the sixth transistor is connected to the control terminal of the driving circuit, and a gate electrode of the sixth transistor is connected to a second scanning signal input terminal to receive the second scanning signal.
For example, in the pixel circuit provided by at least one embodiment of the present disclosure, the fifth transistor is an N-type transistor and the sixth transistor is a P-type transistor, or the fifth transistor is a P-type transistor and the sixth transistor is an N-type transistor.
For example, in the pixel circuit provided by at least one embodiment of the present disclosure, the second reset circuit includes a fourth transistor, a first electrode of the fourth transistor is connected to a reset signal input terminal to receive the reset signal, a second electrode of the fourth transistor is connected to the first terminal of the light-emitting element, and a gate electrode of the fourth transistor is connected to a second reset control signal input terminal to receive the second reset control signal.
For example, the pixel circuit provided by at least one embodiment of the present disclosure further include a storage circuit, wherein the storage circuit is connected to the control terminal of the driving circuit, and is configured for storing the data signal.
For example, in the pixel circuit provided by at least one embodiment of the present disclosure, the storage circuit includes a storage capacitor, a first electrode of the storage capacitor is connected to the control terminal of the driving circuit, and a second electrode of the storage capacitor is connected to a second power signal input terminal to receive a second power signal.
At least one embodiment of the present disclosure further provides a pixel circuit, including a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a driving transistor, and a storage capacitor. A first electrode of the first transistor is connected to a data signal input terminal to receive a data signal, a second electrode of the first transistor is connected to a first electrode of the fifth transistor, and a gate electrode of the first transistor is connected to a first scanning signal input terminal to receive a first scanning signal. A first electrode of the second transistor is connected to a first power signal input terminal to receive a first power signal, a second electrode of the second transistor is connected to a first electrode of the driving transistor, and a gate electrode of the second transistor is connected to a light-emitting control signal input terminal to receive a light-emitting control signal. A first electrode of the third transistor is connected to a reset signal input terminal to receive a reset signal, a second electrode of the third transistor is connected to the first electrode of the driving transistor, and a gate electrode of the third transistor is connected to a first reset control signal input terminal to receive a first reset control signal. A first electrode of the fourth transistor is connected to the reset signal input terminal to receive the reset signal, a second electrode of the fourth transistor is connected to a second electrode of the driving transistor, and a gate electrode of the fourth transistor is connected to a second reset control signal input terminal to receive a second reset control signal. A second electrode of the fifth transistor is connected to a gate electrode of the driving transistor, and a gate electrode of the fifth transistor is connected to the first scanning signal input terminal to receive the first scanning signal. A first electrode of the sixth transistor is connected to the second electrode of the first transistor, a second electrode of the sixth transistor is connected to the gate electrode of the driving transistor, and a gate electrode of the sixth transistor is connected to a second scanning signal input terminal to receive a second scanning signal. A first electrode of the storage capacitor is connected to the gate electrode of the driving transistor, and a second electrode of the storage capacitor is connected to a second power signal input terminal to receive a second power signal.
At least one embodiment of the present disclosure further provides a driving method of a pixel circuit, used for driving the pixel circuit as described in the above-mentioned embodiments, wherein the driving method includes: in a first phase, turning off the first switching circuit by using the first scanning signal, turning off the second switching circuit by using the light-emitting control signal, turning on the first reset circuit by using the first reset control signal, and resetting the first terminal of the driving circuit through the reset signal; in a second phase, turning on the first switching circuit by using the first scanning signal, turning off the second switching circuit by using the light-emitting control signal, turning on the first reset circuit by using the first reset control signal, and writing the data signal to the control terminal of the driving circuit; and in a third phase, turning off the first switching circuit by using the first scanning signal, turning on the second switching circuit by using the light-emitting control signal, and turning off the first reset circuit by using the first reset control signal, so as to allow the driving circuit to drive the light-emitting element to emit light.
For example, in the driving method of the pixel circuit provided by at least one embodiment of the present disclosure, in a case where the pixel circuit further includes a third switching circuit, the driving method further includes: in the first phase, turning off the third switching circuit by using the first scanning signal and the second scanning signal; in the second phase, turning on the third switching circuit by using the first scanning signal and the second scanning signal; and in the third phase, turning off the third switching circuit by using the first scanning signal and the second scanning signal.
At least one embodiment of the present disclosure further provides a display panel, including the pixel circuit as described in the above-mentioned embodiments.
At least one embodiment of the present disclosure further provides a display device, including the pixel circuit as described in the above-mentioned embodiments.
For example, the display device provided by at least one embodiment of the present disclosure further includes an array substrate, the pixel circuit is on the array substrate, the array substrate includes a pixel region and a non-pixel region, and the first reset circuit is in the non-pixel region.
For example, in the display device provided by at least one embodiment of the present disclosure, in a case where the pixel circuit further includes a second reset circuit, the second reset circuit is in the non-pixel region.
In order to clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly described in the following. It is obvious that the described drawings are only related to some embodiments of the present disclosure and thus are not limitative to the present disclosure.
Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in a variety of forms and should not be construed to be limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present disclosure comprehensive and complete, and the concept of the example embodiments will be fully conveyed to those skilled in the art. In the drawings, the same reference numeral represents the same or similar part, and repeated description will be omitted.
Further, the described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will be aware that the technical solutions of the present disclosure may be practiced without one or more of the specific details described, or other methods, components, materials, devices, steps, etc. may be employed. In other cases, well-known structures, methods, devices, implementations, materials, or operations are not shown or described in detail to avoid obscuring aspects of the present disclosure.
The blocks shown in the accompanying drawings is only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or implemented in one or more software hardened modules, or in different networks and/or processor devices and/or microcontroller devices.
Unless otherwise defined, all the technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms “first,” “second,” etc., which are used in the description and the claims of the present application for invention, are not intended to indicate any sequence, amount or importance, but distinguish various components. Also, the terms such as “a,” “an,” etc., are not intended to limit the amount, but indicate the existence of at least one. The terms “comprise,” “comprising,” “include,” “including,” etc., are intended to specify that the elements or the objects stated before these terms encompass the elements or the objects and equivalents thereof listed after these terms, but do not preclude the other elements or objects. The phrases “connect”, “connected”, etc., are not intended to define a physical connection or mechanical connection, but may include an electrical connection, directly or indirectly. “On,” “under,” “right,” “left” and the like are only used to indicate relative position relationship, and when the position of the object which is described is changed, the relative position relationship may be changed accordingly.
In a conventional pixel circuit, because of the influence of the internal parasitic capacitance of the thin film transistor (TFT), there is a voltage difference between the gate electrode and drain electrode of the driving transistor. Usually, the drain electrode of the driving transistor is in the floating state during the reset phase and the data writing phase, so that the level of the gate electrode of the driving transistor is not fixed. Therefore, the level of the gate electrode of the driving transistor may fluctuate due to the parasitic capacitance during the light-emitting phase, thereby causing problems such as uneven display of the display device. At least one embodiment of the present disclosure provides a pixel circuit, and the pixel circuit includes a driving circuit, a first switching circuit, a second switching circuit, and a first reset circuit. The driving circuit includes a first terminal, a second terminal, and a control terminal, and is configured to drive a light-emitting element connected to the second terminal of the driving circuit to emit light. The first switching circuit is configured to be turned on in response to a first scanning signal to transmit a data signal to the control terminal of the driving circuit. The second switching circuit is connected to the first terminal of the driving circuit, and is configured to be turned on in response to a light-emitting control signal to transmit a first power signal to the first terminal of the driving circuit. The first reset circuit is connected to the first terminal of the driving circuit, and is configured to be turned on in response to a first reset control signal to transmit a reset signal to the first terminal of the driving circuit.
At least one embodiment of the present disclosure further provides a driving method of a pixel circuit, used for driving the pixel circuit according to the above embodiments. The method includes: in a first phase, turning off the first switching circuit by using the first scanning signal, turning off the second switching circuit by using the light-emitting control signal, turning on the first reset circuit by using the first reset control signal, and resetting the first terminal of the driving circuit through the reset signal; in a second phase, turning on the first switching circuit by using the first scanning signal, turning off the second switching circuit by using the light-emitting control signal, turning on the first reset circuit by using the first reset control signal, and writing the data signal to the control terminal of the driving circuit; and in a third phase, turning off the first switching circuit by using the first scanning signal, turning on the second switching circuit by using the light-emitting control signal, and turning off the first reset circuit by using the first reset control signal, so as to allow the driving circuit to drive the light-emitting element to emit light.
The pixel circuit provided by at least one embodiment of the present disclosure may reduce the influence of the parasitic capacitance on the level of the gate electrode of the driving transistor during the light-emitting phase, thereby overcoming the problem of uneven display of the display device to a certain extent.
The pixel circuit provided by at least one embodiment of the present disclosure may also reduce the leakage of the storage circuit of the pixel circuit at the control terminal of the first switching circuit, and solve the problem of crosstalk of the display device due to the level loss of the storage circuit caused by the leakage, thereby improving the display quality; and may also reduce loss of the data voltage, increase the range of the data voltage, and facilitate the implementation of fine gray level display.
Hereinafter, embodiments of the present disclosure are described in detail with reference to the accompany drawings. It should be noted that the same reference numerals in different drawings are used to refer to the same described elements.
At least one embodiment of the present disclosure provides a pixel circuit 10. As illustrated in
In at least one embodiment of the present disclosure, for example, a first terminal of the first switching circuit 200 is connected to a data signal input terminal to receive the data signal DATA, a second terminal of the first switching circuit 200 is connected to the control terminal of the driving circuit 100, and a control terminal of the first switching circuit 200 is connected to a first scanning signal input terminal to receive the first scanning signal Sn.
For example, a first terminal of the second switching circuit 300 is connected to a first power signal input terminal to receive the first power signal VDD, a second terminal of the second switching circuit 300 is connected to the first terminal of the driving circuit 100, and a control terminal of the second switching circuit 300 is connected to a light-emitting control signal input terminal to receive the light-emitting control signal EM.
For example, a first terminal of the first reset circuit 400 is connected to a reset signal input terminal to receive the reset signal GND, a second terminal of the first reset circuit 400 is connected to the first terminal of the driving circuit 100, and a control terminal of the first reset circuit 400 is connected to a first reset control signal input terminal to receive the first reset control signal DIS1.
For example, a first terminal of the storage circuit 500 is connected to the control terminal of the driving circuit 100, and a second terminal of the storage circuit 500 is connected to a second power signal input terminal V1. For example, the second power signal input terminal V1 may be configured to keep inputting a low-level DC signal, such as being grounded. The embodiments of the present disclosure are not limited in this aspect.
In the pixel circuit provided by at least one embodiment of the present disclosure, the first reset circuit 400 is turned on in response to the first reset control signal DIS1 to initialize the first terminal of the driving circuit 100 (for example, the first electrode of the driving transistor DT), so as to prevent the first terminal of the driving circuit 100 from be in the floating state during the reset phase and the data writing phase, and meanwhile, to prevent the level of the control terminal of the driving circuit 100 (for example, the gate electrode of the driving transistor DT) from fluctuating during the light-emitting phase due to the influence of parasitic capacitance, thereby alleviating the problem of uneven display of the display device and improving the display quality.
For example, at least one embodiment of the present disclosure further provides a pixel circuit 20. As illustrated in
The third switching circuit 700 is controlled by the first scanning signal Sn and the second scanning signal Sm, which may reduce the leakage of the storage circuit 500 of the pixel circuit at the control terminal of the first switching circuit 200, so that the problem of crosstalk of the display device due to the level loss of the storage circuit 500 caused by the leakage is solved, thereby improving the display quality. Further, the loss of the data voltage is reduced, and the range of the data voltage is increased, so as to facilitate the implementation of fine gray level display.
As illustrated in
For example, the first terminal of the second reset circuit 800 is connected to the reset signal input terminal to receive the reset signal GND, the second terminal of the second reset circuit 800 is connected to the first terminal of the light-emitting element 600, and the control terminal of the second reset circuit 800 is connected to the second reset control signal input terminal to receive the second reset control signal DIS2. For example, as illustrated in
The first terminal of the light-emitting element 600 is initialized through the second reset circuit 800, so as to avoid the afterimage or smear phenomenon during the display of the next frame after one frame is displayed. For example, in some examples, the first reset circuit 400 and the second reset circuit 800 share the same reset control signal DIS. This arrangement may reduce the area of the pixel wiring layer, which may facilitate high PPI design.
It should be noted that, except the third switching circuit 700 and the second reset circuit 800, other circuit structures of the pixel circuit 20 are basically the same as those of the pixel circuit described in
It should also be noted that in the embodiments and drawings of the present disclosure, VSS may represent both the third power signal and the third power signal input terminal; similarly, Sn may represent both the first scanning signal input terminal and the first scanning signal; Sm may represent both the second scanning signal input terminal and the second scanning signal; DATA may represent both the data signal input terminal and the data signal; DIS may represent both the reset control signal input terminal and the reset control signal; DIS1 may represent both the first reset control signal input terminal and the first reset control signal; DIS2 may represent both the second reset control signal input terminal and the second reset control signal ; GND may represent both the reset signal input terminal and the reset signal; EM may represent both the light-emitting control signal input terminal and the light-emitting control signal; VDD may represent both the first power signal input terminal and the first power signal; V1 may represent both the second power signal and the second power signal input terminal; and so on. Details are not described herein again.
The various circuits included in the pixel circuit provided by the embodiments of the present disclosure are described in detail below, and
As illustrated in
For example, the first switching circuit 200 includes a first transistor T1, a first electrode of the first transistor T1 is connected to the data signal input terminal to receive the data signal DATA, a second electrode of the first transistor T1 is connected to the first terminal of the third switching circuit (for example, a first electrode of the fifth transistor T5 and a first electrode of the sixth transistor T6), and a gate electrode of the first transistor T1 is connected to the first scanning signal input terminal to receive the first scanning signal Sn.
For example, the second switching circuit 300 includes a second transistor T2, a first electrode of the second transistor T2 is connected to the first power signal input terminal to receive the first power signal VDD, a second electrode of the second transistor T2 is connected to the first terminal of the driving circuit 100, for example, the first electrode of the driving transistor DT, and a gate electrode of the second transistor T2 is connected to the light-emitting control signal input terminal to receive the light-emitting control signal EM.
For example, the first reset circuit 400 includes a third transistor T3, a first electrode of the third transistor T3 is connected to the reset signal input terminal to receive the reset signal GND, a second electrode of the third transistor T3 is connected to the first terminal of the driving circuit 100, for example, the first electrode of the driving transistor DT, and a gate electrode of the third transistor T3 is connected to the first reset control signal input terminal to receive the first reset control signal DIS1 (i.e., the reset control signal DIS).
For example, the second reset circuit 800 includes a fourth transistor T4, a first electrode of the fourth transistor T4 is connected to the reset signal input terminal to receive the reset signal GND, a second electrode of the fourth transistor T4 is connected to the first terminal of the light-emitting element 600, and a gate electrode of the fourth transistor T4 is connected to the second reset control signal input terminal to receive the second reset control signal DIS2 (i.e., the reset control signal DIS).
For example, as illustrated in
For example, the third switching circuit 700 includes a complementary metal oxide semiconductor (CMOS) circuit, the first terminal of the CMOS circuit is connected to the second terminal of the first switching circuit 200, the second terminal of the CMOS circuit is connected to the control terminal of the driving circuit 100, the first control terminal of the CMOS circuit is connected to the first scanning signal input terminal to receive the first scanning signal Sn, and the second control terminal of the CMOS circuit is connected to the second scanning signal input terminal to receive the second scanning signal Sm. For example, in some examples, the third switching circuit 700 may include a fifth transistor T5 and a sixth transistor T6. For example, in the case where the transistors T1-T4 are all N-type transistors, the fifth transistor T5 may be an N-type transistor, and the sixth transistor T6 may be a P-type transistor. A first electrode of the fifth transistor T5 is connected to a first electrode of the sixth transistor T6 and connected to the second terminal of the first switching circuit 200, for example, the second electrode of the first transistor T1. A second electrode of the fifth transistor T5 is connected to a second electrode of the sixth transistor T6 and connected to the control terminal of the driving circuit 100, for example, the gate electrode of the driving transistor DT. A gate electrode of the fifth transistor T5 is connected to the first scanning signal input terminal to receive the first scanning signal Sn, and a gate electrode of the sixth transistor T6 is connected to the second scanning signal input terminal to receive the second scanning signal Sm. For example, in some examples, the first scanning signal Sn and the second scanning signal Sm are synchronized, and the trigger level of the first scanning signal Sn and the trigger level of the second scanning signal Sm are opposite. For example, in some examples, the trigger level of the first scanning signal Sn is a high level, and the trigger level of the second scanning signal Sm is a low level, which is not specifically limited in the present disclosure.
For example, in at least one embodiment of the present disclosure, the light-emitting element 600 may be an organic light-emitting diode (OLED), a first terminal of the OLED is connected to the second terminal of the driving circuit 100, such as the second electrode of the driving transistor DT, and a second terminal of the OLED is connected to the third power signal input terminal to receive the third power signal VSS. For example, the third power signal VSS may be a low-level signal provided by a stable power supply, which is not specifically limited in the embodiments of the present disclosure.
For example, in at least one embodiment of the present disclosure, the storage circuit 500 may be a storage capacitor Cst. A first electrode of the storage capacitor Cst is connected to the control terminal of the driving circuit 100, such as the gate electrode of the driving transistor DT, and a second electrode of the storage capacitor Cst is connected to the second power signal input terminal V1 . For example, the second power signal input terminal V1 may be configured to provide a low-level signal, which is not specifically limited in the embodiments of the present disclosure. For example, the second power signal provided by the second power signal input terminal V1 and the third power signal VSS may be the same signal, or may be different signals, which is not limited in the embodiments of the present disclosure.
It should be noted that, in the embodiments of the present disclosure, the driving circuit 100, the first switching circuit 200, the second switching circuit 300, the first reset circuit 400, the second reset circuit 800, the third level circuit, and so on all have control terminals, first terminals, and second terminals. Each of the first to sixth transistors T1-T6 has a gate electrode, a first electrode, and a second electrode. Specifically, the control terminal of each circuit may be the gate electrode of the transistor included therein, the first terminal may be the source electrode of the corresponding transistor, and the second terminal may be the drain electrode of the corresponding transistor; or, the first terminal may be the drain electrode of the corresponding transistor, and the second terminal may be the source electrode of the corresponding transistor. In addition, each transistor may also be an enhancement transistor or a depletion transistor, which is not specifically limited in the embodiments of the present disclosure.
The operating process of the pixel circuit in
The first period t1 (a reset phase): the first scanning signal Sn is at a low level, the second scanning signal Sm is at a high level, the reset control signal DIS is at a high level, and the light-emitting control signal EM is at a low level. The first scanning signal Sn turns off the first transistor T1 and the fifth transistor T5, the second scanning signal Sm turns off the sixth transistor, the reset control signal DIS turns on the third transistor T3 and the fourth transistor T4, the light-emitting control signal EM turns off the second transistor T2, and the first electrode of the driving transistor DT and the first terminal of the light-emitting element 600 are reset through the reset signal GND.
The second period t2 (a writing phase): the first scanning signal Sn is at a high level, the second scanning signal Sm is at a low level, the reset control signal DIS is at a high level, and the light-emitting control signal EM is at a low level. The first scanning signal Sn turns on the first transistor T1 and the fifth transistor T5, the second scanning signal Sm turns on the sixth transistor T6, the reset control signal DIS turns on the third transistor T3 and the fourth transistor T4, the light-emitting control signal EM turns off the second transistor T2, and the data signal DATA is written to the storage circuit 500 (for example, the storage capacitor Cst).
The third period t3 (a light-emitting phase): the first scanning signal Sn is at a low level, the second scanning signal Sm is at a high level, the reset control signal DIS is at a low level, and the light-emitting control signal EM is at a high level. The first scanning signal Sn turns off the first transistor T1 and the fifth transistor T5, the second scanning signal Sm turns off the sixth transistor T6, the reset control signal DIS turns off the third transistor T3 and the fourth transistor T4, and the light-emitting control signal EM turns on the second transistor T2 to enable the first power signal VDD to drive the light-emitting element 600 to emit light.
In a conventional pixel circuit, a metal oxide semiconductor (MOS) dual-gate structure (the MOS dual-gate structure may be structurally regarded as a series connection of two single MOS transistors, a second gate electrode being provided in addition to the first gate electrode so as to allow the feedback capacitance between the drain electrode and the first gate electrode to become very small) may reduce the leakage current of the storage capacitor Cst. But the series connection of two single MOS transistors may cause voltage loss of the input data signal DATA, and may reduce the data range, which is not conducive to the implementation of fine gray level display. The embodiments of the present disclosure may reduce the leakage current and reduce voltage loss of the data signal DATA through the MOS dual-gate structure and the CMOS structure (the CMOS structure may be structurally regarded as a parallel connection of two single MOS transistors, and the types of the two single MOS transistors are different, for example, one of the single MOS transistors is of an N type, the other of the single MOS transistors is of a P-type, and vice versa).
It can be obtained from the above analysis that the circuit structure using the combination of the MOS dual-gate structure and the CMOS structure can solve the problem of leakage of the storage capacitor Cst, and can further take into account the voltage range of the data signal DATA.
It should be noted that in the above specific embodiments, T6 is a P-type transistor, and the other transistors are all N-type transistors; but those skilled in the art may easily obtain a pixel circuit of T6 as an N-type transistor and the other transistors as P-type transistors based on the pixel circuit provided by the present disclosure. In an exemplary embodiment of the present disclosure, T6 is an N-type transistor, and the other transistors are P-type transistors. In this case, the first power signal VDD is a low-level signal, the cathode of the OLED is connected to the second node, and the anode of the OLED is connected to a high-level signal. The use of P-type thin film transistors may have the following advantages: for example, strong noise suppression capability; low-level turning-on and easy implementation of low levels in the charging management; P-type thin film transistors with simple manufacturing process and relatively low prices; P-type thin film transistors having better stability; or the like. Certainly, the pixel circuit provided by the present disclosure may also be changed to a CMOS circuit or the like, and may not be limited to the pixel circuit provided in the embodiments, and details are not described herein again.
Exemplary embodiments of the present disclosure further provide a driving method of a pixel circuit, which may be applied to the pixel circuit as illustrated in
Step S910, in the first phase, turning off the first switching circuit by using the first scanning signal, turning off the second switching circuit by using the light-emitting control signal, turning on the first reset circuit by using the first reset control signal, and resetting the first terminal of the driving circuit through the reset signal.
Step S920, in the second phase, turning on the first switching circuit by using the first scanning signal, turning off the second switching circuit by using the light-emitting control signal, turning on the first reset circuit by using the first reset control signal, and writing the data signal to the control terminal of the driving circuit.
Step S930, in the third phase, turning off the first switching circuit by using the first scanning signal, turning on the second switching circuit by using the light-emitting control signal, and turning off the first reset circuit by using the first reset control signal, so as to allow the driving circuit to drive the light-emitting element to emit light.
In the driving method of the pixel circuit provided by the embodiments of the present disclosure, the first reset circuit 400 is turned on in response to the reset signal GND to initialize the first terminal of the driving circuit 100, thereby prevent the first terminal (for example, the first electrode of the driving transistor DT) of the driving circuit 100 from being in the floating state during the reset phase and the data writing phase, and meanwhile, further avoiding the level of the control terminal of the driving circuit 100 (for example, the gate electrode of the driving transistor DT) from fluctuating due to the influence of parasitic capacitance during the light-emitting phase, so that the problem of uneven display of the display device is alleviated, and the display quality is improved.
For example, in at least one embodiment of the present disclosure, in the case where the pixel circuit further includes a third switching circuit, for example, the pixel circuit 20 illustrated in
For example, in some examples, in the case where the first switching circuit 200 includes the first transistor T1, the second switching circuit 300 includes the second transistor T2, the first reset circuit 400 includes the third transistor T3, the second reset circuit 800 includes the fourth transistor T4, the third switching circuit 700 includes the CMOS circuit (for example, reference may be made to the specific structure of the CMOS circuit in the above embodiments, but the structure of the CMOS circuit is not limited to this), and the transistors are all N-type transistors:
in Step S910, the first scanning signal Sn is at a low level, the second scanning signal Sm is at a high level, the reset control signal DIS is at a high level, and the light-emitting control signal EM is at a low level, the first scanning signal Sn, the second scanning signal Sm, the reset control signal DIS, and the light-emitting control signal EM turn on the third transistor T3 and the fourth transistor T4, turn off the first transistor T1, the CMOS circuit, and the second transistor T2, and the first electrode of the driving transistor DT and the first terminal of the light-emitting element 600 are reset through the reset signal GND;
in Step S920, the first scanning signal Sn is at a high level, the second scanning signal Sm is at a low level, the reset control signal DIS is at a high level, and the light-emitting control signal EM is at a low level, the first scanning signal Sn, the reset control signal DIS, and the light-emitting control signal EM turn on the first transistor T1, the CMOS circuit, the third transistor T3, and the fourth transistor T4, and turn off the second transistor T2, and the data signal DATA is written into the storage circuit 500;
in Step S930, the first scanning signal Sn is at a low level, the second scanning signal Sm is at a high level, the reset control signal DIS is at a low level, the light-emitting control signal EM is at a high level, the first scanning signal Sn, the second scanning signal Sm, the reset control signal DIS, and the light-emitting control signal EM turn off the first transistor T1, the CMOS circuit, the third transistor T3, and the fourth transistor T4, and turn on the second transistor T2, so as to enable the first power signal VDD to drive the light-emitting element 600 to emit light.
The third switching circuit 700 is controlled by the first scanning signal Sn and the second scanning signal Sm, which may reduce the leakage of the storage circuit 500 of the pixel circuit, solve the problem of crosstalk of the display device due to level loss of the storage circuit 500 caused by the leakage, and improve the display quality. Further, the loss of the data voltage is reduced, and the range of the data voltage is improved, which may facilitate implementing fine gray level display.
It should be noted that although various steps of the method in the present disclosure are described in a specific order in the drawings, this does not require or imply that these steps must be performed in the specific order, or that all the steps must be performed to achieve the desired result. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step for execution, and/or one step may be divided into multiple steps for execution, etc.
Based on the description of the above embodiments, those skilled in the art may easily understand that the exemplary embodiments described here may be implemented by software, or may be implemented by combining software with necessary hardware. Therefore, the technical solution according to the embodiments of the present disclosure may be provided in the form of a software product, which may be stored in a non-volatile storage medium (which may be a CD-ROM, a U disk, a mobile hard disk, etc.) or in the network, and may include several instructions to cause a computing device (which may be a personal computer, a server, a mobile terminal, a network device, or the like) to execute the method according to the embodiments of the present disclosure.
In addition, the above-mentioned drawings are merely schematic illustrations of the processing included in the method according to the exemplary embodiments of the present disclosure, and are not intended for limitation. It can be readily understood that the processes shown in the above drawings do not indicate or limit the time sequence of these processes. In addition, it can be readily understood that these processes may be executed synchronously or asynchronously in multiple modules.
For example, in an example, the display device 30 includes a gate driver 3010, a timing controller 3020, a data driver 3030, and a display panel 3000. The display panel 3000 includes a plurality of pixel units P defined according to intersection of a plurality of gate lines GL and a plurality of data lines DL. The gate driver 3010 is used to drive the plurality of gate lines GL. The data driver 3030 is used to drive the plurality of data lines DL. The timing controller 3020 is used to process the image data RGB input from the outside of the display device 30, provide the processed image data RGB to the data driver 3030, and output the scanning control signal GCS and the data control signal DCS to the gate driver 3010 and the data driver 3030, so as to control the gate driver 3010 and the data driver 3030.
For example, the display device 30 is a display device provided by any one of the embodiments of the present disclosure, or the display panel 3000 is a display panel provided by any one of the embodiments of the present disclosure. For example, the display device 30 or the display panel 3000 includes the pixel circuit 10 or 20 provided in any one of the above embodiments. For example, the pixel circuit 10 or 20 is provided in the pixel unit P of the pixel array region of the array substrate of the display panel 3000. For example, the first reset circuit 400 in the pixel circuit 10 illustrated in
For example, the plurality of gate lines GL are correspondingly connected to the pixel units P arranged in a plurality of rows. For example, the gate driver 3010 may be implemented as a semiconductor chip, or integrated in the display panel 3000 to form a GOA circuit.
For example, the data driver 3030 uses the reference gamma voltage to convert digital image data RGB input from the timing controller 3020 into data signals according to a plurality of data control signals DCS from the timing controller 3020. The data driver 3030 provides the converted data signals to the plurality of data lines DL. For example, the data driver 3030 may be implemented as a semiconductor chip.
For example, the timing controller 3020 processes image data RGB which is externally input to match the size and the resolution of the display panel 3000, and then provides the processed image data to the data driver 3030. The timing controller 3020 uses synchronization signals (such as a dot clock DCLK, a data enable signal DE, a horizontal synchronization signal Hsync, and a vertical synchronization signal Vsync) input from the outside of the display device 30 to generate the plurality of scanning control signals GCS and the plurality of data control signals DCS. The timing controller 3020 provides the generated scanning control signals GCS and data control signals DCS to the gate driver 3010 and the data driver 3030, respectively, so as to control the gate driver 3010 and the data driver 3030.
The display device 30 may also include other components, such as a signal decoding circuit, a voltage converting circuit, etc. These components may, for example, adopt existing conventional components, and details are not described herein.
The display device 30 provided by at least one embodiment of the present disclosure may reduce the influence of the parasitic capacitance on the level of the gate electrode of the driving transistor during the light-emitting phase, thereby overcoming the problem of uneven display of the display device to a certain extent. Further, the leakage of the storage circuit in the pixel circuit at the control terminal of the first switching circuit may be reduced, and the problem of crosstalk of the display device due to level loss of the storage circuit caused by the leakage may be solved, thereby improving the display quality. Furthermore, the loss of the data voltage is reduced, and the range of the data voltage is improved, thereby facilitating the implementation of fine gray level display.
For example, in at least one embodiment of the present disclosure, as illustrated in
For example, in some examples, as illustrated in
It should be noted that, in the embodiments of the present disclosure, the display device 40 may be, for example, any product or component with a display function, such as an OLED TV, a display, a mobile phone, a tablet computer, a notebook computer, a digital photo frame, a navigator, etc. The embodiments of the present disclosure are not limited in this aspect. For the technical effects of the display device 40, reference may be made to the above descriptions of the pixel circuit 10/20, and details are not described herein again.
The following statements should be noted:
(1) The accompanying drawings involve only the structure(s) in connection with the embodiment(s) of the present disclosure, and other structure(s) can adopt common design(s).
(2) In case of no conflict, the embodiments of the present disclosure and the features in the embodiments may be combined with each other to obtain a new embodiment.
Those skilled in the art will easily think of other embodiments of the present disclosure after considering the description and practicing the invention disclosed herein. The present application is intended to cover any variation, use or adaptive change of the present disclosure, which follows the general principle of the present disclosure and includes common knowledge or conventional technical means in the art not disclosed in the present disclosure. The description and embodiments are only regarded as illustrative. The true scope and spirit of the present disclosure are indicated by the claims.
It should be understood that the present disclosure is not limited to the particular structure described above and shown in the drawings, and various modifications and changes may be made without departing from the scope of the present disclosure. The scope of the present disclosure is merely limited by the attached claims.
Number | Date | Country | Kind |
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201910209387.4 | Mar 2019 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2020/079591 | 3/17/2020 | WO | 00 |