This application claims priority to Chinese Patent Application No. 202410383558.6 filed with the China National Intellectual Property Administration (CNIPA) on Mar. 29, 2024, the disclosure of which is incorporated herein by reference in its entirety.
The present disclosure relates to the field of display technology and, in particular, a display panel, a method for driving a display panel, and a display device.
With the development of digital technology, more and more display devices such as electronic papers (EPs) have entered people's lives. Electronic papers can keep displaying for a long time when the power is off and have the advantages such as lightness, thinness, low power consumption and a simple technique. Therefore, the electronic papers are increasingly favored by people.
A display principle of a color electronic paper is that color electrophoretic particles in an electrophoretic display layer are driven by an electric field so that the color electrophoretic particles are arranged in a particular manner to display a required color image.
The color electronic paper needs a data signal with a relatively high voltage for implementing color display, resulting in a relatively large voltage drop (current resistance (IR) drop) generated on a data signal line for transmitting the data signal and also an increase in the power consumption of the color electronic paper.
The present disclosure provides a display panel, a method for driving a display panel, and a display device.
According to an aspect of the present disclosure, a display panel is provided. The display panel includes a pixel circuit, and the pixel circuit includes a drive transistor and a boosting unit. A first electrode of the drive transistor is connected to a pixel electrode. A first terminal of the boosting unit is connected to a first data signal line, and the first data signal line is configured to receive a first data signal. A second terminal of the boosting unit is connected to a gate of the drive transistor, or a second terminal of the boosting unit is connected to a second electrode of the drive transistor.
According to another aspect of the present disclosure, a method for driving a display panel is provided and used for driving the display panel described above. A working period of the pixel circuit includes a data write stage.
The driving method includes the steps described below.
In the data write stage, the first data signal line provides the first data signal to the first terminal of the boosting unit.
The boosting unit increases a voltage of the first data signal.
According to another aspect of the present disclosure, a display device is provided. The display device includes a display panel, the display panel includes a pixel circuit, and the pixel circuit includes a drive transistor and a boosting unit. A first electrode of the drive transistor is connected to a pixel electrode. A first terminal of the boosting unit is connected to a first data signal line, and the first data signal line is configured to receive a first data signal. A second terminal of the boosting unit is connected to a gate of the drive transistor, or a second terminal of the boosting unit is connected to a second electrode of the drive transistor.
In the display panel, the driving method thereof and the display device provided in embodiments of the present disclosure, the boosting unit is disposed in the pixel circuit. The boosting unit is used for raising the voltage input from the first terminal of the boosting unit and outputting the raised voltage from the second terminal of the boosting unit. The first terminal of the boosting unit is electrically connected to the first data signal line and configured to receive the first data signal transmitted from the first data signal line, and the first data signal boosted by the boosting unit is output from the second terminal of the boosting unit. The second terminal of the boosting unit is electrically connected to the gate or the second electrode of the drive transistor to output the boosted first data signal to the gate or the second electrode of the drive transistor.
It is to be understood that the content described in this section is neither intended to identify key or critical features of the embodiments of the present disclosure nor intended to limit the scope of the present disclosure. Other features of the present disclosure become easily understood through the description provided hereinafter.
To illustrate solutions of embodiments of the present disclosure more clearly, the drawings used in the description of the embodiments are briefly described hereinafter. Apparently, the drawings described hereinafter illustrate part of the embodiments of the present disclosure, and those of ordinary skill in the art may obtain other drawings based on the drawings described hereinafter on the premise that no creative work is done.
To make solutions of the present disclosure better understood by those skilled in the art, solutions of embodiments of the present disclosure are described hereinafter clearly and completely in conjunction with drawings in embodiments of the present disclosure. Apparently, the embodiments described hereinafter are part, not all, of embodiments of the present disclosure. Based on embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art are within the scope of the present disclosure on the premise that no creative work is done.
It is to be noted that terms “first”, “second”, and the like in the description, claims, and drawings of the present disclosure are used for distinguishing between similar objects and are not necessarily used for describing a particular order or sequence. It is to be understood that data used in this manner are interchangeable in appropriate cases so that the embodiments of the present disclosure described herein can be implemented in an order not illustrated or described herein. In addition, terms “comprising”, “including”, and any variation thereof are intended to encompass a non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units not only includes the expressly listed steps or units, but may also include other steps or units that are not expressly listed or are inherent to such a process, method, product, or device.
Further, electrophoretic particles of different colors carry different charges. When a particular data signal voltage is applied to the pixel electrode, electrophoretic particles carrying corresponding charges may move in a direction facing or facing away from the pixel electrode. Therefore, positions of electrophoretic particles of different colors in the electrophoretic display layer can be accurately controlled by providing different data signal voltages. In this manner, electrophoretic particles of a plurality of colors simultaneously or partially appear on the surface of the electrophoretic display layer to form color mixing and display a colored display effect.
To prevent color contamination and ensure sharpness and saturation of color display, the data signal voltage needs a relatively large voltage span to cover all necessary voltage ranges, thereby ensuring that positions of electrophoretic particles of each color can be accurately controlled. Therefore, the data signal line 32′ can provide a data signal voltage with a relatively large voltage span range to the pixel electrode. For example, the data signal line 32′ generally needs to provide a data signal voltage within a range of ±28 V, that is, the data signal line 32′ needs to transmit the data signal voltage within the entire voltage interval from −28 V to +28 V.
Further, whether the drive transistor T0′ is turned on depends on whether a voltage difference between the gate g0′ of the drive transistor T0 and the second electrode s0′ of the drive transistor T0′ exceeds a threshold voltage Vth0′ of the drive transistor T0′. Therefore, to enable the drive transistor T0′ to turn on, a voltage of the scan signal received by the gate g0′ of the drive transistor T0′ is set to be higher than a sum of the voltage of the data signal input from the second electrode s0′ of the drive transistor T0′ and the threshold voltage Vth0′. For example, assuming that the threshold voltage Vth0′ of the drive transistor T0′ is about 1 V, when a value range of the data signal voltage is ±28 V, the voltage of the scan signal received by the gate g0′ of the drive transistor T0′ needs to be within a range of about ±30 V.
When the voltage of the gate g0′ of the drive transistor T0′ is high enough, the drive transistor T0′ can work in a saturated region. In the state, the drive transistor T0′ has a smaller on-resistance and a larger on-current. Therefore, a larger voltage of the gate g0′ can enable the drive transistor T0′ to quickly enter the saturated region to provide a larger on-current, thereby quickly and fully writing the data signal into the pixel electrode, shortening the charging time of a pixel and contributing to improving an image refresh rate of the display panel.
Therefore, when the value range of the data signal voltage is ±28 V, the scan signal line 31′ generally needs to provide the voltage of the scan signal of ±38 V to the gate g0′ of the drive transistor T0′, that is, the scan signal line 31′ needs to be able to transmit the voltage of the scan signal within the entire voltage interval from −38 V to +38 V. In this manner, the drive transistor T0′ can work in the saturated region to provide a larger on-current, thereby quickly and efficiently writing the data signal.
However, high voltages on the data signal line 32′ and the scan signal line 31′ may cause a larger IR drop of wires and larger power consumption of the product.
Embodiments of the present disclosure provide a display panel. The display panel includes a pixel circuit. The pixel circuit includes a drive transistor and a boosting unit. A first electrode of the drive transistor is connected to a pixel electrode. A first terminal of the boosting unit is connected to a first data signal line. The first data signal line is configured to receive a first data signal. A second terminal of the boosting unit is connected to a gate of the drive transistor, or the second terminal of the boosting unit is connected to a second electrode of the drive transistor.
Using the above technical solution, the boosting unit is disposed in the pixel circuit. The boosting unit is used for raising a voltage input from the first terminal of the boosting unit and outputting the raised voltage from the second terminal of the boosting unit. The first terminal of the boosting unit is electrically connected to the first data signal line for receiving the first data signal transmitted from the first data signal line, and the first data signal boosted by the boosting unit is output from the second terminal of the boosting unit. The second terminal of the boosting unit is electrically connected to the gate or the second electrode of the drive transistor to output the boosted first data signal to the gate or the second electrode of the drive transistor so that a higher voltage can be loaded at the gate or the second electrode of the drive transistor through the first data signal with a lower voltage transmitted by the first data signal line. In this manner, while a requirement for a larger voltage interval at the gate or the second electrode of the drive transistor is met, a voltage value of the first data signal transmitted on the first data signal line is reduced, thereby effectively reducing an IR drop of the first data signal line and reducing the overall power consumption.
The preceding is the core idea of the present disclosure. Technical solutions of embodiments of the present disclosure are described clearly and completely hereinafter in conjunction with drawings in the embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without any creative effort are within the scope of the present disclosure.
As shown in
Both the plurality of pixel circuits 10 and the plurality of pixel electrodes 22 may be arranged in an array. Arrangement manners of the plurality of pixel circuits 10 and the plurality of pixel electrodes 22 are not limited to the arrangement manner shown in
With continued reference to
It is to be noted that a pixel capacitor Cep in
Further, electrophoretic particles of different colors carry different charges. When a particular voltage signal is applied to the pixel electrode 22, electrophoretic particles carrying corresponding charges may move in a direction facing or facing away from the pixel electrode 22. Therefore, positions of electrophoretic particles of different colors in the electrophoretic display layer 34 can be accurately controlled by writing different signal voltages into the pixel electrode 22 by the drive transistor T0. In this manner, electrophoretic particles of a plurality of colors simultaneously or partially appear on the surface of the electrophoretic display layer 34, thereby forming the color mixing and displaying the colored display effect.
As described above, to prevent color contamination, ensure sharpness and saturation of color display and ensure an image fresh rate of the display panel, a voltage at the second electrode s0 of the drive transistor T0 needs to be within a voltage interval of ±28 V, and the voltage at the gate g0 of the drive transistor T0 needs to be within a voltage interval of ±38 V. As a result, a larger IR drop may be generated on a signal line that provides a corresponding signal to the second electrode s0 or the gate g0 of the drive transistor T0 and power consumption may be increased.
As shown in
The first terminal 211 of the boosting unit 21 is electrically connected to the first data signal line 23 for receiving the first data signal transmitted from the first data signal line 23. The boosting unit 21 increases a voltage value of the first data signal through the internal boosting mechanism. Subsequently, the boosted first data signal is output from the second terminal 212 of the boosting unit 21. It is to be understood that the voltage output from the second terminal 212 of the boosting unit 21 is greater than the voltage of the first data signal loaded on the first data signal line 23.
With continued reference to
In another embodiment, as shown in
In conclusion, in the display panel provided in the embodiment of the present disclosure, the boosting unit is disposed in the pixel circuit. The boosting unit is used for raising the voltage input from the first terminal of the boosting unit and outputting the raised voltage from the second terminal of the boosting unit. The first terminal of the boosting unit is electrically connected to the first data signal line for receiving the first data signal transmitted from the first data signal line, and the first data signal boosted by the boosting unit is output from the second terminal of the boosting unit. The second terminal of the boosting unit is electrically connected to the gate or the second electrode of the drive transistor to output the boosted first data signal to the gate or the second electrode of the drive transistor so that the transmission of the first data signal with a lower voltage by the first data signal line can implement the loading of a higher voltage at the gate or the second electrode of the drive transistor. In this manner, the requirement for a larger voltage interval at the gate or the second electrode of the drive transistor is met, and the voltage value of the first data signal transmitted on the first data signal line is reduced at the same time, thereby effectively reducing the IR drop of the first data signal line and reducing the overall power consumption.
With continued reference to
As shown in
The second electrode s1 of the first transistor T1 is used as the first terminal 211 of the boosting unit 21 and electrically connected to the first data signal line 23 for receiving the first data signal provided by the first data signal line 23.
The first electrode d1 of the first transistor T1 is electrically connected to the first electrode c11 of the bootstrap capacitor C1. When the first transistor T1 is turned on, the first transistor T1 transmits the first data signal provided by the first data signal line 23 to the first electrode c11 of the bootstrap capacitor C1.
The first electrode d1 of the first transistor T1 is also used as the second terminal 212 of the boosting unit 21. Therefore, the first electrode d1 of the first transistor T1 and the first electrode c11 of the bootstrap capacitor C1 are also electrically connected to the gate g0 or the second electrode s0 of the drive transistor T0.
The gate g2 of the second transistor T2 is electrically connected to the second scan signal line 26 for receiving the second scan signal provided by the second scan signal line 26. The second scan signal is used to enable the second transistor T2 to turn on. If the second transistor T2 is an n-type transistor, the second scan signal may be a high-level signal. If the second transistor T2 is a p-type transistor, the second scan signal may be a low-level signal.
The second electrode s2 of the second transistor T2 is electrically connected to the second electrode s1 of the first transistor T1. As the first terminal 211 of the boosting unit 21, the second electrode s1 of the first transistor T1 is electrically connected to the first data signal line 23. Therefore, the second electrode s2 of the second transistor T2 is also electrically connected to the first data signal line 23 for receiving the first data signal provided by the first data signal line 23.
The first electrode d2 of the second transistor T2 is connected to the second electrode c12 of the bootstrap capacitor C1. When the second transistor T2 is turned on, the second transistor T2 transmits the first data signal provided by the first data signal line 23 to the second electrode c12 of the bootstrap capacitor C1.
A working principle of the boosting unit 21 depends on alternating conduction between the first transistor T1 and the second transistor T2 and charging and discharging processes of the bootstrap capacitor C1. Under a particular timing, when the first scan signal and the second scan signal alternately trigger the first transistor T1 and the second transistor T2 to turn on, the bootstrap capacitor C1 can accumulate and maintain a potential difference higher than an input voltage at the two electrodes of the bootstrap capacitor C1 through bootstrap, thereby boosting the voltage.
The first transistor T1 can be controlled to turn on by the first scan signal line 25. The second transistor T2 can be controlled to turn on by the second scan signal line 26. Therefore, a turning-on opportunity and order of the first transistor T1 and the second transistor T2 can be controlled by the first scan signal line 25 and the second scan signal line 26.
In a charging stage t0, the first scan signal line 25 provides the first scan signal Gate1. In this case, the first transistor T1 is turned on, the second transistor T2 is turned off, and the first transistor T1 conducts between the second electrode s1 of the first transistor T1 and the first electrode d1 of the first transistor T1 so that the first data signal line 23 is connected to the first electrode c11 of the bootstrap capacitor C1 by the first transistor T1, the first data signal Data1 provided by the first data signal line 23 is applied to the first electrode c11 of the bootstrap capacitor C1 and a voltage at the first electrode c11 of the bootstrap capacitor C1 rises to the voltage of the first data signal Data1.
In a bootstrap stage t1, the second scan signal line 26 provides the second scan signal Gate2. In this case, the second transistor T2 is turned on, the first transistor T1 is turned off, and the second transistor T2 conducts the second electrode s2 of the second transistor T2 and the first electrode d2 of the second transistor T2 so that conduction between the first data signal line 23 and the second electrode c12 of the bootstrap capacitor C1 is permitted the second transistor T2, the first data signal Data1 provided by the first data signal line 23 is applied to the second electrode c12 of the bootstrap capacitor C1 and a voltage at the second electrode c12 of the bootstrap capacitor C1 rises to the voltage of the first data signal Data1. Since a voltage difference between the first electrode c11 and the second electrode c12 of the bootstrap capacitor C1 does not vary suddenly, a coupling variation occurs at the first electrode c11 of the bootstrap capacitor C1 due to a voltage variation of the second electrode c12 of the bootstrap capacitor C1 so that a bootstrap voltage higher than the voltage of the first data signal Data1 is generated at the first electrode c11 of the bootstrap capacitor C1, thereby implementing a boosting function of the boosting unit 21.
A voltage value of the generated bootstrap voltage is related to the voltage value of the first data signal Data1. For example, if the voltage value of the bootstrap voltage is two times the voltage value of the first data signal Data1, the voltage value output from the second terminal 212 of the boosting unit 21 is two times the voltage value of the first data signal Data1.
Further, as shown in
It is to be noted that the structure of the boosting unit 21 is not limited to the preceding embodiment. In another embodiment, another boosting mechanism may also be used in the boosting unit 21 to implement the boosting function, which is not limited in the embodiments of the present disclosure.
With continued reference to
As shown in
Further, as shown in
As shown in
In the data write stage tw, the first data signal line 23 provides the first data signal Data1 to the first terminal 211 of the boosting unit 21.
The data write stage tw includes a first sub-stage tw1 and a second sub-stage tw2 in sequence.
In the first sub-stage tw1, the first scan signal line 25 provides the first scan signal Gate1 to the gate g1 of the first transistor T1. The first scan signal Gate1 is an effective pulse for controlling the first transistor T1 to turn on to write the first data signal Data1 into the gate g0 of the drive transistor T0.
In the second sub-stage tw2, the second scan signal line 26 provides the second scan signal Gate2 to the gate g2 of the second transistor T2. The second scan signal Gate2 is an effective pulse for controlling the second transistor T2 to turn on to increase the voltage of the gate g0 of the drive transistor T0.
As shown in
When the pixel circuit 10 is working, the first sub-stage tw1 and the second sub-stage tw2 are performed in sequence.
In the first sub-stage tw1, the first scan signal line 25 provides the first scan signal Gate1 to the gate g1 of the first transistor T1. The first scan signal Gate1 is an effective pulse for controlling the first transistor T1 to turn on. For example, when the first transistor T1 is an n-type transistor, the first scan signal Gate1 may be a high-level pulse signal, and when the first transistor T1 is a p-type transistor, the first scan signal Gate1 may be a low-level pulse signal. In
Further, the first scan signal Gate1 enables the first transistor T1 to turn on. In this case, the first transistor T1 conducts between the second electrode s1 of the first transistor T1 and the first electrode d1 of the first transistor T1, the second transistor T2 is turned off, the first data signal line 23 is connected to the first electrode c11 of the bootstrap capacitor C1 by the first transistor T1, and the first data signal Data1 provided by the first data signal line 23 is applied to the first electrode c11 of the bootstrap capacitor C1 so that the voltage at the first electrode c11 of the bootstrap capacitor C1 (a voltage at the first node N1) is the voltage of the first data signal Data1.
In the second sub-stage tw2, the second scan signal line 26 provides the second scan signal Gate2 to the gate g2 of the second transistor T2. The second scan signal Gate2 is an effective pulse for controlling the second transistor T2 to turn on. For example, when the second transistor T2 is an n-type transistor, the second scan signal Gate2 may be a high-level pulse signal, and when the second transistor T2 is a p-type transistor, the second scan signal Gate2 may be a low-level pulse signal. In
Further, the second scan signal Gate2 enables the second transistor T2 to turn on. In this case, the second transistor T2 conducts between the second electrode s2 of the second transistor T2 and the first electrode d2 of the second transistor T2, the first transistor T1 is turned off, conduction between the first data signal line 23 and the second electrode c12 of the bootstrap capacitor C1 is permitted through the second transistor T2, the first data signal Data1 provided by the first data signal line 23 is applied to the second electrode c12 of the bootstrap capacitor C1, and the voltage at the second electrode c12 of the bootstrap capacitor C1 rises to the voltage of the first data signal Data1. Since the voltage difference between the first electrode c11 and the second electrode c12 of the bootstrap capacitor C1 does not vary suddenly, the coupling variation occurs at the first electrode c11 of the bootstrap capacitor C1 due to the voltage variation of the second electrode c12 of the bootstrap capacitor C1 so that the bootstrap voltage higher than the voltage of the first data signal Data1 is generated at the first electrode c11 of the bootstrap capacitor C1. The voltage value of the bootstrap voltage may be two times the voltage value of the first data signal Data1. In this case, the voltage value at the first node N1 rises to be two times the voltage value of the first data signal Data1, the drive transistor T0 is turned on, conduction between the second data signal line 27 and the pixel electrode 22 is permitted, and the second data signal Data2 provided by the second data signal line 27 is written into the second node N2 by the drive transistor T0 so that a voltage of the pixel electrode 22 (a voltage at the second node N2) is a voltage of the second data signal Data2, thereby forming the electric field between the pixel electrode 22 and the common electrode layer 33. Different second data signals are written into the pixel electrode 22 by the second data signal line 27 so that positions of electrophoretic particles of different colors between the pixel electrode 22 and the common electrode layer 33 in the electrophoretic display layer 34 can be accurately controlled and electrophoretic particles of a plurality of colors simultaneously or partially appear on the surface of the electrophoretic display layer 34, thereby forming the color mixing and displaying the colored display effect.
With continued reference to
|(1/2)*data2|<|data1| is set so that it can ensure that the drive transistor T0 is turned on in the second sub-stage tw2. Moreover, |data1|<|data2| is set so that a smaller voltage data1 of the first data signal Data1 transmitted on the first data signal line 23 can be ensured and the IR drop of the first data signal line 23 is smaller, thereby contributing to lowering the power consumption.
As shown in
In the present embodiment, the voltage data1 of the first data signal Data1 is set to be at least half of the voltage data2 of the second data signal Data2 so that the voltage of the first data signal Data1 boosted by the boosting unit 21 exceeds the voltage data2 of the second data signal Data2 and in the second sub-stage tw2, the voltage written into the first node N1 (the voltage of the gate g0 of the drive transistor T0) is greater than the voltage data2 of the second data signal Data2. The voltage at the gate g0 of the drive transistor T0 is greater than the voltage of the second electrode s0 of the drive transistor T0 so that the drive transistor T0 can be turned on. In this case, the second data signal Data2 provided by the second data signal line 27 is written into the second node N2 by the drive transistor T0 to load the voltage data2 of the second data signal Data2 on the pixel electrode 22, thereby implementing a display function.
Further, when a voltage difference of the gate g0 of the drive transistor T0 relative to the second electrode s0 of the drive transistor T0 is greater than a threshold voltage Vth0 of the drive transistor T0, it can be ensured that the drive transistor T0 is turned on. Therefore, |2*data1−data2|>|Vth0| may be further set, thereby contributing to enabling the drive transistor T0 to fully turn on in the second sub-stage tw2, accelerating a speed of writing the voltage data2 of the second data signal Data2 into the second node N2, shortening the charging time of the pixel electrode 22 and contributing to an improvement of the image refresh rate of the display panel. The threshold voltage Vth0 of the drive transistor T0 is a positive value, and the specific value of the threshold voltage Vth0 of the drive transistor T0 is determined by a process parameter of the drive transistor T0 and is not limited in the embodiments of the present disclosure.
It is to be noted that in the embodiment of the present disclosure, the drive transistor T0 being the n-type transistor only is used as an example for description, but is not limited thereto.
In another embodiment, the drive transistor T0 may also be a p-type transistor. In this case, the voltage of the gate g0 of the drive transistor T0 needs to be less than the voltage data2 of the second data signal Data2 so that the drive transistor T0 can be turned on. The voltage data1 of the first data signal Data1 is set to be less than half of the voltage data2 of the second data signal Data2 so that the voltage of the first data signal Data1 processed by the boosting unit 21 is less than the voltage data2 of the second data signal Data2 and in the second sub-stage tw2, the voltage written into the first node N1 (the voltage of the gate g0 of the drive transistor T0) is less than the voltage data2 of the second data signal Data2. The voltage of the gate g0 of the drive transistor T0 is less than the voltage of the second electrode s0 of the drive transistor T0 so that the drive transistor T0 can be turned on. In this case, the second data signal Data2 provided by the second data signal line 27 is written into the second node N2 by the drive transistor T0 to load the voltage data2 of the second data signal Data2 on the pixel electrode 22, thereby implementing the display function.
Further, when the voltage difference of the gate g0 of the drive transistor T0 relative to the second electrode s0 of the drive transistor T0 is less than the threshold voltage Vth0 of the drive transistor T0, it can be ensured that the drive transistor T0 is turned on. Therefore, |2*data|−data2|>|Vth0| may be further set, thereby contributing to enabling the drive transistor T0 to fully turn on in the second sub-stage tw2, accelerating the speed of writing the voltage data2 of the second data signal Data2 to the second node N2, shortening the charging time of the pixel electrode 22 and contributing to the improvement of the image refresh rate of the display panel. The threshold voltage Vth0 of the drive transistor T0 is a positive value. The specific value of the threshold voltage Vth0 of the drive transistor T0 is determined by the process parameter of the drive transistor T0 and is not limited in the embodiments of the present disclosure.
The voltage data1 of the first data signal Data1 corresponding to each pixel circuit 10 may be separately set according to the voltage data2 of the second data signal Data2 corresponding to the pixel circuit 10. When the voltage data1 of the first data signal Data1 corresponding to a pixel circuit 10 varies, the voltage data2 of the second data signal Data2 corresponding to the pixel circuit 10 may vary accordingly. That is, the voltage data1 of the first data signal Data1 of each pixel circuit 10 is separately controlled. The detailed control of the voltage data1 of the first data signal Data1 corresponding to each pixel circuit 10 can ensure that each pixel circuit 10 can work normally, and at the same time, the voltage data1 of the first data signal Data1 corresponding to each pixel circuit 10 can be reduced as much as possible, thereby reducing the IR drop of the first data signal line 23 and reducing the power consumption.
With continued reference to
As shown in
Further, as shown in
In the display panel provided in the embodiment of the present disclosure, while the requirement for a larger voltage interval on the pixel electrode 22 is met, the voltage value of the first data signal transmitted on the first data signal line 23 can be reduced, thereby reducing the IR drop of the first data signal line 23 and reducing the power consumption.
In the data write stage tw, the first data signal line 23 provides the first data signal Data1 to the first terminal 211 of the boosting unit 21.
The data write stage tw includes a first sub-stage tw1 and a second sub-stage tw2 in sequence.
In the first sub-stage tw1, the first scan signal line 25 provides the first scan signal Gate1 to the gate g1 of the first transistor T1. The first scan signal Gate1 is an effective pulse for controlling the first transistor T1 to turn on to write the first data signal Data1 into the second electrode s0 of the drive transistor T0.
In the second sub-stage tw2, the second scan signal line 26 provides the second scan signal Gate2 to the gate g2 of the second transistor T2. The second scan signal Gate2 is an effective pulse for controlling the second transistor T2 to turn on to increase the voltage of the second electrode s0 of the drive transistor T0.
As shown in
When the pixel circuit 10 is working, the first sub-stage tw1 and the second sub-stage tw2 are performed in sequence.
In the first sub-stage tw1, the first scan signal line 25 provides the first scan signal Gate1 to the gate g1 of the first transistor T1. The first scan signal Gate1 is an effective pulse for controlling the first transistor T1 to turn on. For example, when the first transistor T1 is an n-type transistor, the first scan signal Gate1 may be a high-level pulse signal, and when the first transistor T1 is a p-type transistor, the first scan signal Gate1 may be a low-level pulse signal. In
Further, the first scan signal Gate1 enables the first transistor T1 to turn on. In this case, the first transistor T1 conducts between the second electrode s1 of the first transistor T1 and the first electrode d1 of the first transistor T1, conduction between the second transistor T2 is turned off, the first data signal line 23 and the first electrode c11 of the bootstrap capacitor C1 is permitted through the first transistor T1, and the first data signal Data1 provided by the first data signal line 23 is applied to the first electrode c11 of the bootstrap capacitor C1 so that the voltage at the first electrode c11 of the bootstrap capacitor C1 (the voltage at the first node N1) is the voltage of the first data signal Data1.
In the second sub-stage tw2, the second scan signal line 26 provides the second scan signal Gate2 to the gate g2 of the second transistor T2, and the third scan signal line 28 provides the third scan signal Gate3 to the gate g0 of the drive transistor T0.
The second scan signal Gate2 is an effective pulse for controlling the second transistor T2 to turn on. For example, when the second transistor T2 is an n-type transistor, the second scan signal Gate2 may be a high-level pulse signal, and when the second transistor T2 is a p-type transistor, the second scan signal Gate2 may be a low-level pulse signal. In
The third scan signal Gate3 is an effective pulse for controlling the drive transistor T0 to turn on. For example, when the drive transistor T0 is an n-type transistor, the third scan signal Gate3 may be a high-level pulse signal, and when the drive transistor T0 is a p-type transistor, the third scan signal Gate3 may be a low-level pulse signal. In
Further, the second scan signal Gate2 enables the second transistor T2 to turn on, and the third scan signal Gate3 enables the drive transistor T0 to turn on. In this case, the second transistor T2 conducts between the second electrode s2 of the second transistor T2 and the first electrode d2 of the second transistor T2, the first transistor T1 is turned off, conduction between the first data signal line 23 and the second electrode c12 of the bootstrap capacitor C1 is permitted through the second transistor T2, the first data signal Data1 provided by the first data signal line 23 is applied to the second electrode c12 of the bootstrap capacitor C1, and the voltage at the second electrode c12 of the bootstrap capacitor C1 rises to the voltage of the first data signal Data1. Since the voltage difference between the first electrode c11 and the second electrode c12 of the bootstrap capacitor C1 does not vary suddenly, the coupling variation occurs at the first electrode c11 of the bootstrap capacitor C1 due to the voltage variation of the second electrode c12 of the bootstrap capacitor C1 so that the bootstrap voltage higher than the voltage of the first data signal Data1 is generated at the first electrode c11 of the bootstrap capacitor C1. The voltage value of the bootstrap voltage may be two times the voltage value of the first data signal Data1 so that the voltage value at the first node N1 rises to be two times the voltage value of the first data signal Data1.
The drive transistor T0 conducts between the second electrode s0 of the drive transistor T0 and the first electrode do of the drive transistor T0. The bootstrap voltage is written into the second node N2 by the drive transistor T0 so that the voltage of the pixel electrode 22 (the voltage at the second node N2) is two times the voltage value of the first data signal Data1, thereby forming the electric field between the pixel electrode 22 and the common electrode layer 33. Different first data signals are applied to the first node N1 by the first data signal line 23 so that different bootstrap voltages can be written into the pixel electrode 22, positions of electrophoretic particles of different colors between the pixel electrode 22 and the common electrode layer 33 in the electrophoretic display layer 34 can be accurately controlled and electrophoretic particles of a plurality of colors simultaneously or partially appear on the surface of the electrophoretic display layer 34, thereby forming the color mixing and displaying the colored display effect.
The voltage of the first scan signal Gate1 is gate1, the voltage of the second scan signal Gate2 is gate2, and the voltage of the first data signal Data1 is data1, where |gate1|>|data1|, and |gate2|>|data1|.
Setting |gate1|>|data1| facilitates ensuring that when the first scan signal Gate1 is loaded at the gate g1 of the first transistor T1, the first transistor T1 can be turned on. Setting gate2|>|data1| facilitates ensuring that when the second scan signal Gate2 is loaded at the gate g2 of the second transistor T2, the second transistor T2 can be turned on.
As shown in
Further, when a voltage difference of the gate gl of the first transistor T1 relative to the second electrode s1 of the first transistor T1 is greater than a threshold voltage Vth1 of the first transistor T1, it can be ensured that the first transistor T1 is turned on. Therefore, |gate1−data1|>|Vth1| may be further set, thereby contributing to ensuring that the first transistor T1 can be fully turned on. In this case, the threshold voltage Vth1 of the first transistor T1 is a positive value. A specific value of the threshold voltage Vth1 of the first transistor T1 is determined by a process parameter of the first transistor T1 and is not limited in the embodiments of the present disclosure.
Similarly, the second electrode s2 of the second transistor T2 is the source and receives the first data signal Data1. A voltage of the second electrode s2 of the second transistor T2 is the voltage data1 of the first data signal Data1. When a voltage of the gate g2 of the second transistor T2 is greater than the voltage of the second electrode s2 of the second transistor T2, the second transistor T2 can be turned on. Therefore, setting the voltage gate2 of the second scan signal Gate2 to be greater than the voltage data1 of the first data signal Data1 facilitates ensuring that when the second scan signal Gate2 is loaded at the gate g2 of the second transistor T2, the second transistor T2 can be turned on.
Further, when a voltage difference of the gate g2 of the second transistor T2 relative to the second electrode s2 of the second transistor T2 is greater than a threshold voltage Vth2 of the second transistor T2, it can be ensured that the second transistor T2 is turned on. Therefore, |gate2−data1|≥|Vth2| may be further set, thereby contributing to enabling the second transistor T2 to fully turn on. In this case, the threshold voltage Vth2 of the second transistor T2 is a positive value. A specific value of the threshold voltage Vth2 of the second transistor T2 is determined by a process parameter of the second transistor T2 and is not limited in the embodiment of the present disclosure.
In another embodiment, the first transistor T1 and the second transistor T2 may also be p-type transistors. In this case, when the voltage of the gate g1 of the first transistor T1 is less than the voltage of the second electrode s1 of the first transistor T1, the first transistor T1 can be turned on. Therefore, setting the voltage gate1 of the first scan signal Gate1 to be less than the voltage data1 of the first data signal Data1 facilitates ensuring that when the first scan signal Gate1 is loaded at the gate g1 of the first transistor T1, the first transistor T1 can be turned on.
Further, when the voltage difference of the gate g1 of the first transistor T1 relative to the second electrode s1 of the first transistor T1 is less than the threshold voltage Vth1 of the first transistor T1, it can be ensured that the first transistor T1 is turned on. Therefore, |gate1−data1|>|Vth1| may be further set, thereby contributing to ensuring that the first transistor T1 can be fully turned on. In this case, the threshold voltage Vth1 of the first transistor T1 is a negative value. The specific value of the threshold voltage Vth1 of the first transistor T1 is determined by the process parameter of the first transistor T1 and is not limited in the embodiments of the present disclosure.
Similarly, when the voltage of the gate g2 of the second transistor T2 is less than the voltage of the second electrode s2 of the second transistor T2, the second transistor T2 can be turned on. Therefore, setting the voltage gate2 of the second scan signal Gate2 to be less than the voltage data1 of the first data signal Data1 facilitates ensuring that when the second scan signal Gate2 is loaded at the gate g2 of the second transistor T2, the second transistor T2 can be turned on.
Further, when a voltage difference of the second electrode s2 of the second transistor T2 relative to the gate g2 of the second transistor T2 is greater than the threshold voltage Vth2 of the second transistor T2, it can be ensured that the second transistor T2 is turned on. Therefore, |gate2−data1|>|Vth2| may be further set, thereby contributing to ensuring that the second transistor T2 can be fully turned on. In this case, the threshold voltage Vth2 of the second transistor T2 is a negative value. The specific value of the threshold voltage Vth2 of the second transistor T2 is determined by the process parameter of the second transistor T2 and is not limited in the embodiments of the present disclosure.
With continued reference to
As shown in
Further, the third scan signal line 28 and the second scan signal line 26 are the same signal line so that the second transistor T2 and the drive transistor T0 are controlled to turn on in the second sub-stage tw2 at the same time, the number of signal lines can be reduced, thereby saving the space and cost and contributing to a decrease in wiring complexity.
The voltage gate1 of the first scan signal Gate1 is set to be within a voltage interval of a smaller range so that the first scan signal Gate1 with a lower voltage can be transmitted on the first scan signal line 25, thereby reducing an IR drop of the first scan signal line 25 and reducing power consumption.
Moreover, the third scan signal line 28 and the second scan signal line 26 are the same signal line, and the voltage gate2 of the second scan signal Gate2 and the voltage gate3 of the third scan signal Gate3 have the same voltage value. Setting the voltage gate2 of the second scan signal Gate2 to be within a voltage interval of a larger range can ensure that both the second transistor T2 and the drive transistor T0 can be turned on in the second sub-stage tw2.
The case where each of the first transistor T1, the second transistor T2 and the drive transistor T0 is an n-type transistor is used as an example for description. The voltage gate1 of the first scan signal Gate1 is greater than the voltage data1 of the first data signal Data1. For example, |gate1−data1|>|Vth1| can ensure that the first transistor T1 is turned on, where Vth1 is the threshold voltage of the first transistor T1.
The voltage gate2 of the second scan signal Gate2 is greater than the voltage data1 of the first data signal Data1. For example, |gate2−data1|>|Vth2| can ensure that the second transistor T2 is turned on, where Vth2 is the threshold voltage of the second transistor T2.
As shown in
Therefore, the voltage gate1 of the first scan signal Gate1 and the voltage gate2 of the second scan signal Gate2 only need to be greater than the voltage data1 of the first data signal Data1 so that the first transistor T1 and the second transistor T2 can be controlled to turn on. The voltage gate3 of the third scan signal Gate3 needs to be greater than two times the voltage data1 of the first data signal Data1 so that the drive transistor T0 can be controlled to turn on.
In the present embodiment, the third scan signal line 28 and the second scan signal line 26 are the same signal line, and the voltage gate2 of the second scan signal Gate2 and the voltage gate3 of the third scan signal Gate3 have the same voltage value. The voltage gate2 of the second scan signal Gate2 is set to be greater than the voltage gate1 of the first scan signal Gate1 (for example, the voltage gate2 of the second scan signal Gate2 is set to be greater than two times the voltage data1 of the first data signal Data1), thereby ensuring that both the second transistor T2 and the drive transistor T0 can be turned on in the second sub-stage tw2.
For example, if the voltage of the first node N1 needs to meet the voltage interval of ±28 V and the voltage of the gate g0 of the drive transistor T0 needs to meet the voltage interval of ±38 V, the voltage data1 of the first data signal Data1 needs to meet a voltage interval of ±14 V. In this case, a range of the voltage gate1 of the first scan signal Gate1 may be a voltage interval of ±14 V at the lowest, and a range of the voltage gate2 of the second scan signal Gate2 may be a voltage interval of ±38 V at the lowest.
Further, the voltage gate3 of the third scan signal Gate3 meets that the maximum value of |gate3| is greater than the maximum value of |gate2| to ensure that the drive transistor T0 can be turned on in the second sub-stage tw2.
For example, if the voltage of the first node N1 needs to meet the voltage interval of ±28 V and the voltage of the gate g0 of the drive transistor T0 needs to meet the voltage interval of ±38 V, the voltage data1 of the first data signal Data1 needs to meet a voltage interval of ±14 V. In this case, the range of the voltage gate1 of the first scan signal Gate1 may be the voltage interval of ±14 V at the lowest, the range of the voltage gate2 of the second scan signal Gate2 may be the voltage interval of ±14 V at the lowest, and the range of the voltage gate3 of the third scan signal Gate3 may be the voltage interval of ±38 V at the lowest.
As shown in
It is to be understood that if the effective pulse is a low-level pulse signal, the end moment of the first scan signal Gate1 is a moment where the rising edge of the first scan signal Gate1 is located and the start moment of the second scan signal Gate2 is a moment where the falling edge of the second scan signal Gate2 is located.
In an actual situation, the first scan signal Gate1 and the second scan signal Gate2 may not be ideal square wave signals, and certain transition time (edge delays) may exist on the rising edges and the falling edges of the first scan signal Gate1 and the second scan signal Gate2. Moreover, the transistors are also not instantaneously turned on or off, and certain switch delays exist. Therefore, as shown in
It is to be noted that the interval time al between the end moment of the first scan signal Gate1 and the start moment of the second scan signal Gate2 may be set according to an actual requirement. The interval time al may be set at a microsecond level, for example, 0<a1≤100 μs, thereby facilitating an improvement of the operating frequency and overall response speed of the pixel circuit and thus facilitating an improvement on the refresh rate of the display panel.
As shown in
In another embodiment, as shown in
The reset transistor T4 is used to clear or reset charges accumulated by the bootstrap capacitor C1 in the previous frame, thereby reducing an effect of the residual charges in the previous frame on a bootstrap voltage in the current frame, contributing to improving the accuracy and stability of the bootstrap voltage and further contributing to improving image display quality and reducing a display error.
As shown in
The first electrode s4 of the reset transistor T4 is electrically connected to the reset signal line 29 and receives the reset signal provided by the reset signal line 29. When the fourth scan signal enables the reset transistor T4 to turn on, the reset signal can be transmitted from the first electrode s4 of the reset transistor T4 to the second electrode d4 of the reset transistor T4.
Further, as shown in
With continued reference to
In the reset stage tv, the fourth scan signal line 30 provides the fourth scan signal Gate4 to the gate g4 of the reset transistor T4. The fourth scan signal Gate4 is an effective pulse for controlling the reset transistor T4 to turn on to write the reset signal into the first electrode c11 of the bootstrap capacitor C1 or the second electrode c12 of the bootstrap capacitor C1.
In the data write stage tw, the first data signal line 23 provides the first data signal Data1 to the first terminal 211 of the boosting unit 21.
As shown in
In the reset stage tv, the fourth scan signal line 30 provides the fourth scan signal Gate4 to the gate g4 of the reset transistor T4. The fourth scan signal Gate4 provided by the fourth scan signal line 30 to the gate g4 of the reset transistor T4 is an effective pulse for controlling the reset transistor T4 to turn on. For example, when the reset transistor T4 is an n-type transistor, the fourth scan signal Gate4 may be a high-level pulse signal, and when the reset transistor T4 is a p-type transistor, the fourth scan signal Gate4 may be a low-level pulse signal. In
Further, the fourth scan signal Gate4 enables the reset transistor T4 to turn on. In this case, the reset transistor T4 conducts between the first electrode s4 of the reset transistor T4 and the second electrode d4 of the reset transistor T4 so that conduction between the reset signal line 29 and one of the first electrode c11 or the second electrode c12 of the bootstrap capacitor C1 is permitted and the reset signal Vref provided by the reset signal line 29 is applied to one of the first electrode c11 or the second electrode c12 of the bootstrap capacitor C1 to counteract or clear the residual charges on the bootstrap capacitor C1 from the previous frame.
In the data write stage tw, the first data signal line 23 provides the first data signal Data1 to the first terminal 211 of the boosting unit 21. For a working process of the data write stage tw, reference may be made to the preceding embodiments, which is not repeated here.
In the reset stage tv before the data write stage tw, the residual charges on the bootstrap capacitor C1 from the previous frame have been counteracted or cleared, thereby reducing the effect of the residual charges on the bootstrap capacitor C1 from the previous frame on the bootstrap voltage in the current frame and contributing to improving the accuracy and stability of the bootstrap voltage.
Further, the reset signal line 29 may be electrically connected to the common electrode layer 33. In this case, as shown in
With continued reference to
As shown in
Setting a larger capacitance value for the bootstrap capacitor C1 (for example, the capacitance value of the bootstrap capacitor C1 is greater than or equal to the capacitance value of the storage capacitor Cst) facilitates the improvement of the bootstrap effect of the bootstrap capacitor C1 and the improvement of the accuracy and stability of the bootstrap voltage, thereby improving the image display quality and reducing the display error.
Moreover, setting a smaller capacitance value for the storage capacitor Cst can reduce a size of the storage capacitor Cst, thereby improving integration of the display panel and improving a pixel density.
It is to be noted that specific capacitance values of the bootstrap capacitor C1 and the storage capacitor Cst may be set according to actual requirements and are not limited in the embodiments of the present disclosure.
In addition, as shown in
Both the first transistor T1 and the second transistor T2 are metal oxide thin-film transistors, and/or both the first transistor T1 and the second transistor T2 are double-gate transistors.
A metal oxide (indium gallium zinc oxide, IGZO) thin-film transistor has a relatively small leakage current in an off state. Therefore, the first transistor T1 and the second transistor T2 are IGZO transistors. When the first transistor T1 and the second transistor T2 are turned off, an ideal voltage level can be more accurately maintained at the first node N1, thereby ensuring that the drive transistor T0 can be accurately turned on or off and improving display quality.
In addition, a double-gate structure of the double-gate transistor can enhance the control of a working state of the transistor and further reduce a leakage current. Therefore, the first transistor T1 and the second transistor T2 are double-gate transistors. When the first transistor T1 and the second transistor T2 are turned off, the ideal voltage level can also be more accurately maintained at the first node N1, thereby ensuring that the drive transistor T0 can be accurately turned on or off and improving the display quality.
With continued reference to
As shown in
Further, as shown in
Similarly, one of the first electrode c11 or the second electrode c12 of the bootstrap capacitor C1 may also be disposed in the same layer as the first gate T03. In this manner, one metal layer can be reduced, thereby achieving the object of reducing the production cost and reducing the thickness of the panel. Moreover, one of the first electrode c11 or the second electrode c12 of the bootstrap capacitor C1 may be further made of the same material as the first gate T03 so that one of the first electrode c11 or the second electrode c12 of the bootstrap capacitor C1 and the first gate T03 can be prepared in the same preparation process, thereby shortening the time of the preparation process.
It is to be noted that in
As shown in
Further, as shown in
Further, as shown in
Similarly, one of the first electrode c11 or the second electrode c12 of the bootstrap capacitor C1 may also be disposed in the same layer as the light-shielding layer 36. In this manner, one metal layer can be reduced, thereby achieving the object of reducing the production cost and reducing the thickness of the panel. Moreover, one of the first electrode c11 or the second electrode c12 of the bootstrap capacitor C1 may be further made of the same material as the light-shielding layer 36 so that one of the first electrode c11 or the second electrode c12 of the bootstrap capacitor C1 and the light-shielding layer 36 can be prepared in the same preparation process, thereby shortening the time of the preparation process.
In
Further, the first transistor T1 and the second transistor T2 may have the same structure as the drive transistor T0, for example, the BCE structure or top-gate structure, so that the first transistor T1 and the second transistor T2 can be prepared with the drive transistor T0 in the same preparation process to improve the production efficiency and reduce the process complexity and preparation cost.
For example, each of the first transistor T1, the second transistor T2 and the drive transistor T0 may have a top-gate structure. The drive transistor T0 has the top-gate structure, thereby implementing a higher on-current. When the drive transistor T0 is turned on, the higher on-current helps the data signal to be quickly and fully written into the pixel electrode, thereby shortening the charging time of a pixel and facilitating the improvement of the image refresh rate of the display panel.
Moreover, the first transistor T1 and the second transistor T2 have the top-gate structure so that the gates of the first transistor T1 and the second transistor T2 have strong control forces over charges in channel regions of the first transistor T1 and the second transistor T2, thereby more effectively controlling the on state and the off state of the first transistor T1 and the second transistor T2. Meanwhile, a generally small parasitic capacitance of the top-gate structure helps an improvement on a switch speed of the first transistor T1 and the second transistor T2, to reduce a delay and improve the response time and refresh rate of the display panel.
As shown in
The form of the plurality of sub-capacitors C11 connected in parallel is used in the bootstrap capacitor C1 so that while the requirement for the capacitance value of the bootstrap capacitor C1 is met, a single sub-capacitor C11 may have a small capacitance value. For example, the capacitance value of the sub-capacitor C11 may be less than or equal to the capacitance value of the storage capacitor Cst to reduce the size of the sub-capacitor C11, thereby contributing to further improving the integration of the display panel and improving the pixel density.
It is to be noted that in the pixel circuits shown in
A channel width-to-length ratio of the drive transistor T0 is greater than a channel width-to-length ratio of the first transistor T1, and/or a channel width-to-length ratio of the drive transistor T0 is greater than a channel width-to-length ratio of the second transistor T2.
A channel width-to-length ratio refers to a ratio of the width to the length of a channel of a transistor. The larger the channel width-to-length ratio, the larger the conductive area of the transistor, the larger the conduction area, and the larger the current allowed to flow through the transistor within the per unit time.
In the present embodiment, the channel width-to-length ratio of the drive transistor T0 is set to be larger so that the drive transistor T0 can provide a larger on-current, thereby improving the write speed of the data signal of the pixel electrode and contributing to achieving a display effect of a higher frame rate.
Further, when the first transistor T1 and the second transistor T2 are working, switching between the on state and the off state is generally performed instead of continuous transmission with a large current. Therefore, on the premise of ensuring that the first transistor T1 and the second transistor T2 have enough switch performance, the channel width-to-length ratio of the first transistor T1 and/or the channel width-to-length ratio of the second transistor T2 can be appropriately reduced, that is, the first transistor T1 and/or the second transistor T2 has a smaller channel width-to-length ratio. In this manner, an area occupied by the first transistor T1 and/or an area occupied by the second transistor T2 can be reduced, thereby facilitating the improvement of the pixel density of the display panel and the implementation of a higher resolution.
As shown in
In the present embodiment, as shown in
Moreover, the second pixel circuit 10B located in the edge display region 51 is greatly affected by the circuit structure in the bezel region. The capacitance value of the bootstrap capacitor C1 in the second pixel circuit 10B is set to be larger, thereby improving the bootstrap effect of the bootstrap capacitor C1 in the second pixel circuit 10B, improving the stability of a bootstrap voltage, facilitating in solving the interference suffered by the second pixel circuit 10B and the improvement on a drive capability of the second pixel circuit 10B, effectively reducing the difference between the display effect of the central display region 50 and the display effect of the edge display region 51 and improving the display uniformity of an image.
Areas and ranges of the central display region 50 and the edge display region 51 may be set according to actual requirements and are not limited in the embodiments of the present disclosure.
With continued reference to
As described above, the first pixel circuit 10A located in the central display region 50 is less affected by the circuit structure in the bezel region. In the present embodiment, the first transistor T1 and/or the second transistor T2 in the first pixel circuit 10A has a smaller channel width-to-length ratio so that while the requirements for display and driving of the central display region 50 is met, an area occupied by the first transistor T1 and/or an area occupied by the second transistor T2 can be reduced, thereby contributing to improving the pixel density of the display panel and implementing a higher resolution.
Moreover, the second pixel circuit 10B located in the edge display region 51 is greatly affected by the circuit structure in the bezel region. In the present embodiment, the first transistor T1 and/or the second transistor T2 in the second pixel circuit 10B has a larger channel width-to-length ratio, thereby improving the switch performance of the first transistor T1 and/or the second transistor T2, facilitating enhancement of an interference rejection capability and driving strength of the second pixel circuit 10B, facilitating in solving the interference suffered by the second pixel circuit 10B, effectively reducing the difference between the display effect of the central display region 50 and the display effect of the edge display region 51 and improving the display uniformity of the image.
With continued reference to
As described above, the first pixel circuit 10A located in the central display region 50 is less affected by the circuit structure in the bezel region. In the present embodiment, the drive transistor T0 in the first pixel circuit 10A has a smaller channel width-to-length ratio so that while the requirements for display and driving of the central display region 50 is met, an area occupied by the drive transistor T0 can be reduced, thereby contributing to improving the pixel density of the display panel and implementing a higher resolution.
Moreover, the second pixel circuit 10B located in the edge display region 51 is greatly affected by the circuit structure in the bezel region. In the present embodiment, the drive transistor T0 in the second pixel circuit 10B has a larger channel width-to-length ratio so that the drive transistor T0 can provide a larger on-current, thereby facilitating an improvement of the drive capability of the second pixel circuit 10B, helping to solve the interference suffered by the second pixel circuit 10B, effectively reducing the difference of the display effect between the central display region 50 and the edge display region 51 and improving the display uniformity of the image.
As shown in
In the present embodiment, as shown in
A capacitance value of the auxiliary capacitor C2 may be set according to an actual requirement and is not limited in the embodiment of the present disclosure.
The display panel provided in the embodiment of the present disclosure is a display panel of an electronic paper.
As shown in
In another embodiment, the electrophoretic display layer 34 may include at least two types of the white electrophoretic particle W, the red electrophoretic particle R, the yellow electrophoretic particle Y and the blue electrophoretic particle B, which is not limited in the embodiments of the present disclosure.
The common electrode layer 33 is disposed between the second substrate 42 and the electrophoretic display layer 34 and used for transmitting the common voltage Vcom. The common voltage Vcom is a constant voltage.
The pixel electrodes 22 are disposed between the first substrate 41 and the electrophoretic display layer 34. A plurality of pixel regions P are disposed in the display panel. Each pixel region P corresponds to a respective pixel electrode 22. The pixel electrodes 22 are electrically connected to a plurality of pixel circuits 10 correspondingly.
The common electrode layer 33 receives the common voltage Vcom, and the pixel electrode 22 receives the data signal. The electric field can be formed between the pixel electrode 22 and the common electrode layer 33. The electric field generates the attraction force or the repulsive force to the electrophoretic particles so that the electrophoretic particles move under the action of the electric field.
Further, electrophoretic particles of different colors carry different charges. When a particular voltage signal is applied to the pixel electrode 22, electrophoretic particles carrying corresponding charges may move in the direction facing or facing away from the pixel electrode 22. Therefore, different data signals are written into the pixel electrode 22 by the pixel circuit 10 so that positions of electrophoretic particles of different colors in the electrophoretic display layer 34 can be accurately controlled and electrophoretic particles of a plurality of colors simultaneously or partially appear on the surface of the electrophoretic display layer 34, thereby forming the color mixing and displaying the colored display effect.
For example, a charge property of the blue electrophoretic particle B is the same as a charge property of the red electrophoretic particle R but a threshold voltage of the blue electrophoretic particle B is less than a threshold voltage of the red electrophoretic particle R. When a voltage difference between the pixel electrode 22 and the common electrode layer 33 is greater than the threshold voltage of the blue electrophoretic particle B and less than the threshold voltage of the red electrophoretic particle R, the blue electrophoretic particle B moves, and the red electrophoretic particle R does not move. When the voltage difference between the pixel electrode 22 and the common electrode layer 33 is greater than the threshold voltage of the red electrophoretic particle R, both the blue electrophoretic particle B and the red electrophoretic particle R move. In this manner, different data signals are written into the pixel electrode 22 by the pixel circuit 10 so that positions of the blue electrophoretic particle B and the red electrophoretic particle R in the electrophoretic display layer 34 can be accurately controlled and at least one of the blue electrophoretic particle B and the red electrophoretic particle R appear on the surface of the electrophoretic display layer 34, thereby achieving a blue, red or purple display effect.
As shown in
Based on the same inventive concept, embodiments of the present disclosure further provide a method for driving a display panel used for driving any display panel provided in the preceding embodiments. Structures and explanations of terms which are the same as or correspond to the structures and explanations of terms of the preceding embodiments are not repeated here.
In S110, in the data write stage, the first data signal line provides the first data signal to the first terminal of the boosting unit.
In S120, the boosting unit increases a voltage of the first data signal.
A working period of the pixel circuit includes the data write stage. In the data write stage, the first data signal line provides the first data signal to the first terminal of the boosting unit. The boosting unit increases a voltage value of the first data signal through the internal boosting mechanism. Subsequently, the boosted first data signal is output from the second terminal of the boosting unit. It is to be understood that the voltage output from the second terminal of the boosting unit is greater than the voltage of the first data signal provided by the first data signal line.
Further, the second terminal of the boosting unit is electrically connected to the gate or the second electrode of the drive transistor so that the boosted first data signal is output to the gate or the second electrode of the drive transistor and the transmission of the first data signal with a lower voltage by the first data signal line can implement the loading of a higher voltage at the gate or the second electrode of the drive transistor. In this manner, while the requirement for a larger voltage interval at the gate or the second electrode of the drive transistor is met, the voltage value of the first data signal transmitted on the first data signal line is reduced, thereby effectively reducing the IR drop of the first data signal line and reducing the overall power consumption.
The boosting unit includes a first switch transistor, a second switch transistor and a bootstrap capacitor or includes a first transistor, a second transistor and a bootstrap capacitor. A gate of the first transistor is connected to a first scan signal line, the first scan signal line receives a first scan signal, and a first electrode of the first transistor is connected to a first electrode of the bootstrap capacitor. A gate of the second transistor is connected to a second scan signal line, the second scan signal line receives a second scan signal, a first electrode of the second transistor is connected to a second electrode of the bootstrap capacitor, and a second electrode of the second transistor is connected to a second electrode of the first transistor. The second electrode of the first transistor is used as the first terminal of the boosting unit, and the first electrode of the first transistor is used as the second terminal of the boosting unit.
The data write stage includes a first sub-stage and a second sub-stage in sequence.
The step of increasing the voltage of the first data signal through the boosting unit includes the following.
In the first sub-stage, the first scan signal line provides the first scan signal to the gate of the first transistor. The first scan signal is an effective pulse for controlling the first transistor to turn on.
In the second sub-stage, the second scan signal line provides the second scan signal to the gate of the second transistor. The second scan signal is an effective pulse for controlling the second transistor to turn on.
In the first sub-stage, the first scan signal line provides the first scan signal to the gate of the first transistor. In this case, the first transistor is turned on, the second transistor is turned off, and the first transistor conducts between the second electrode of the first transistor and the first electrode of the first transistor so that conduction between the first data signal line and the first electrode of the bootstrap capacitor is permitted through the first transistor, the first data signal provided by the first data signal line is applied to the first electrode of the bootstrap capacitor and a voltage at the first electrode of the bootstrap capacitor rises to the voltage of the first data signal.
In the second sub-stage, the second transistor is turned on at this time, the first transistor is turned off, and the second transistor conducts between the second electrode of the second transistor and the first electrode of the second transistor so that conduction between the first data signal line and the second electrode of the bootstrap capacitor is permitted through the second transistor, the first data signal provided by the first data signal line is applied to the second electrode of the bootstrap capacitor and a voltage at the second electrode of the bootstrap capacitor rises to the voltage of the first data signal. Since a voltage difference between the first electrode and the second electrode of the bootstrap capacitor does not vary suddenly, a coupling variation occurs at the first electrode of the bootstrap capacitor due to a voltage variation of the second electrode of the bootstrap capacitor so that a bootstrap voltage higher than the voltage of the first data signal is generated at the first electrode of the bootstrap capacitor, thereby implementing the boosting function of the boosting unit.
A voltage value of the generated bootstrap voltage is related to the voltage value of the first data signal. For example, if the voltage value of the bootstrap voltage is two times the voltage value of the first data signal, the voltage value output from the second terminal of the boosting unit is two times the voltage value of the first data signal.
Further, the second terminal of the boosting unit is electrically connected to the gate or the second electrode of the drive transistor so that the bootstrap voltage is output to the gate or the second electrode of the drive transistor and the transmission of the first data signal with a lower voltage by the first data signal line can implement the loading of a higher voltage at the gate or the second electrode of the drive transistor. In this manner, while the requirement for a larger voltage interval at the gate or the second electrode of the drive transistor is met, the voltage value of the first data signal transmitted on the first data signal line is reduced, thereby effectively reducing the IR drop of the first data signal line and reducing the overall power consumption.
In the same data write stage, interval time between an end moment of the first scan signal and a start moment of the second scan signal is greater than 0.
As shown in
It is to be understood that if the effective pulse is a low-level pulse signal, the end moment of the first scan signal Gate1 is a moment where the rising edge of the first scan signal Gate1 is located and the start moment of the second scan signal Gate2 is a moment where the falling edge of the second scan signal Gate2 is located.
In an actual situation, the first scan signal Gate1 and the second scan signal Gate2 may not be ideal square wave signals, and certain transition time (edge delays) may exist on the rising edges and the falling edges of the first scan signal Gate1 and the second scan signal Gate2. Moreover, the transistors are also not instantaneously turned on or off, and certain switch delays exist. Therefore, as shown in
It is to be noted that the interval time al between the end moment of the first scan signal Gate1 and the start moment of the second scan signal Gate2 may be set according to an actual requirement. The interval time al may be set at a microsecond level, for example, 0<a1≤100 μs, thereby facilitating the improvement of an operating frequency and overall response speed of the pixel circuit and the improvement of the refresh rate of the display panel.
In the same data write stage, the duration of the first scan signal is less than or equal to the duration of the second scan signal.
As shown in
In another embodiment, as shown in
The boosting unit further includes a reset transistor, a first electrode of the reset transistor is connected to a reset signal line, and the reset signal line is configured to receive a reset signal. A gate of the reset transistor is electrically connected to a fourth scan signal line. The fourth scan signal line is configured to receive a fourth scan signal. A second electrode of the reset transistor is electrically connected to the first electrode of the bootstrap capacitor, and/or a second electrode of the reset transistor is electrically connected to the second electrode of the bootstrap capacitor.
The working period of the pixel circuit further includes a reset stage before the data write stage. In the reset stage, the fourth scan signal line provides the fourth scan signal to the gate of the reset transistor. The fourth scan signal is an effective pulse for controlling the reset transistor to turn on.
As shown in
In the reset stage tv, the fourth scan signal line provides the fourth scan signal to the gate of the reset transistor. The fourth scan signal is an effective pulse for controlling the reset transistor to turn on. For example, when the reset transistor is an n-type transistor, the fourth scan signal Gate4 may be a high-level pulse signal, and when the reset transistor is a p-type transistor, the fourth scan signal Gate4 may be a low-level pulse signal. In
Further, the fourth scan signal Gate4 enables the reset transistor to turn on. In this case, the reset transistor conducts between the first electrode of the reset transistor and the second electrode of the reset transistor so that conduction between the reset signal line and the first electrode and/or the second electrode of the bootstrap capacitor is permitted and the reset signal Vref provided by the reset signal line is applied to the first electrode and/or the second electrode of the bootstrap capacitor, thereby counteracting or clearing the residual charges on the bootstrap capacitor from the previous frame, reducing the effect of the residual charges on the bootstrap capacitor C1 from the previous frame on the bootstrap voltage in the current frame and contributing to improving the accuracy and stability of the bootstrap voltage.
Based on the same inventive concept, embodiments of the present disclosure further provide a display device.
The display device 60 provided in the embodiment of the present disclosure may be the cellphone shown in
It is to be understood that various forms of processes shown above may be adopted with steps reordered, added or deleted. For example, the steps described in the present disclosure may be performed in parallel, sequentially or in different sequences, as long as the desired results of the solutions of the present disclosure can be achieved, and no limitation is imposed herein.
The preceding embodiments do not limit the scope of the present disclosure. It is to be understood by those skilled in the art that various modifications, combinations, sub-combinations, and substitutions may be performed according to design requirements and other factors. Any modification, equivalent substitution, improvement or the like made within the spirit and principle of the present disclosure is within the scope of the present disclosure.
Number | Date | Country | Kind |
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202410383558.6 | Mar 2024 | CN | national |