Display panel, display device, pixel circuit, and driving method

Abstract

This disclosure provides a display panel, a display device, a pixel circuit, and a driving method. The pixel spaces in the display panel are filled with a transparent liquid, and black charged particles or colored charged particles are dispersed within the transparent liquid. A first substrate includes: a plurality of pixel electrodes, at least one common electrode, and at least one reflective electrode. The plurality of pixel electrodes are disposed opposite to a plurality of enclosed pixel spaces in a one-to-one correspondence. The at least one common electrode and the pixel spaces have overlapping areas, and the at least one reflective electrode and the pixel spaces have overlapping areas. The overlapping areas of any pixel space and the common electrode, and the overlapping areas of the pixel electrode corresponding to that pixel space, are spaced apart in a predetermined direction, which is parallel to a direction of the display panel. The overlapping area of ​​any pixel space and the reflective electrode is at least located between the overlapping areas of the pixel space and the common electrode and the overlapping areas of the pixel electrode corresponding to that pixel space.

Description

Technical Field

[0001] This disclosure belongs to the field of display technology, and specifically relates to a display panel, display device, pixel circuit and driving method. Background Technology

[0002] This section is intended to provide background or context for the embodiments set forth in the claims. The description herein is not an admission that it is prior art simply because it is included in this section.

[0003] Figure 1 The image shown depicts a pixel structure in an electronic ink display panel of the related art. Applying different voltage differences between the upper and lower electrodes 1a and 1b causes the microcapsules 1c (filled with black and white particles) between them to display different colors. This display panel has a low grayscale level, resulting in a coarse display image. Summary of the Invention

[0004] This disclosure provides a display panel, a display device, a pixel circuit, and a driving method.

[0005] This disclosure adopts the following technical solution: a display panel, comprising: a first substrate, a second substrate, and a pixel wall; the first substrate and the second substrate are disposed opposite to each other, and the pixel wall is disposed between the first substrate and the second substrate to form a plurality of closed pixel spaces, the pixel spaces being filled with a transparent liquid, wherein black charged particles or colored charged particles are dispersed in the transparent liquid; the first substrate comprises: a plurality of pixel electrodes, at least one common electrode, and at least one reflective electrode, the plurality of pixel electrodes being disposed opposite to the plurality of closed pixel spaces in a one-to-one correspondence, the at least one common electrode having an overlapping area with the pixel space, the at least one reflective electrode having an overlapping area with the pixel space, the overlapping area of ​​any pixel space with the common electrode and the overlapping area of ​​the pixel electrode corresponding to any pixel space being spaced apart in a set direction, the set direction being a direction parallel to the display panel, and the overlapping area of ​​any pixel space with the reflective electrode being at least located between the overlapping area of ​​any pixel space with the common electrode and the overlapping area of ​​the pixel electrode corresponding to any pixel space.

[0006] In some embodiments, the transparent liquid contains dispersed black charged particles, and the first substrate further includes: a plurality of color filter layers, the plurality of color filter layers being disposed opposite to the plurality of pixel spaces in a one-to-one correspondence, the color filter layers being located on the side of the reflective electrode close to the second substrate.

[0007] In some embodiments, black charged particles are dispersed in the transparent liquid, and the second substrate includes a plurality of color filter layers, wherein the plurality of color filter layers are disposed opposite to the plurality of pixel spaces in a one-to-one correspondence.

[0008] In some embodiments, the second substrate includes a black matrix, wherein the opening regions of the black matrix are disposed opposite to the pixel space in a one-to-one correspondence.

[0009] In some embodiments, the pixel space is arranged in an array, and the set direction is an arrangement direction of the pixel space.

[0010] In some embodiments, the reflective electrode is suspended in the air.

[0011] This disclosure adopts the following technical solution: a display driving method for driving the aforementioned display panel, the display driving method comprising:

[0012] A common voltage is applied to the common electrode, and a first voltage and a second voltage are alternately applied to the pixel electrode, wherein one of the first voltage and the second voltage is greater than the common voltage and the other is less than the common voltage, and the absolute value of the difference between the first voltage and the common voltage is greater than the absolute value of the difference between the second voltage and the common voltage, wherein the duty cycle of the first voltage provided to the pixel electrode corresponding to the pixel space is controlled according to the gray level to be displayed in the pixel space.

[0013] This disclosure adopts the following technical solution: a pixel circuit, the pixel circuit comprising: a writing circuit and a conversion circuit, the writing circuit being used to write display data voltage to a storage node, the conversion circuit being used to output a square wave signal with a duty cycle corresponding to the voltage value of the storage node, wherein the duty cycle of the square wave signal is positively or negatively correlated with the voltage value of the storage node.

[0014] In some embodiments, the conversion circuit includes a first transistor, a second transistor, and a third transistor. The gate of the first transistor is connected to the first source-drain of the third transistor, the drain of the first transistor is connected to a first power supply terminal, and the source of the first transistor is connected to the source of the second transistor and used to output the square wave signal. The drain and gate of the second transistor are both connected to a second power supply terminal, and the polarities of the first transistor and the second transistor are opposite. The gate of the third transistor is connected to the memory node, and the second source-drain of the third transistor receives a scan signal, the scan signal having a time period that changes monotonically with time.

[0015] In some embodiments, the write circuit includes a fourth transistor and a storage capacitor, wherein the gate of the fourth transistor receives a gate control signal, the first source-drain of the fourth transistor receives a data voltage, the second source-drain of the fourth transistor is connected to the storage node and the first terminal of the storage capacitor, and the second terminal of the storage capacitor is connected to a fixed voltage terminal.

[0016] This disclosure adopts the following technical solution: a driving method for the aforementioned pixel circuit, comprising:

[0017] During the data writing phase, the displayed data voltage is written to the storage node;

[0018] During the grayscale adjustment stage, a square wave signal with a duty cycle corresponding to the voltage value of the storage node is output, wherein the duty cycle of the square wave signal is positively or negatively correlated with the voltage of the display data.

[0019] The present disclosure adopts the following technical solution: a display device, including the aforementioned display panel.

[0020] In some embodiments, the display panel integrates the aforementioned pixel circuit, wherein each pixel circuit corresponds to a pixel electrode, and the pixel circuit provides the square wave signal to the corresponding pixel electrode. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an electronic ink display panel in related technologies.

[0022] Figure 2 This is a schematic diagram of the structure of a display panel according to an embodiment of the present disclosure.

[0023] Figure 3 This is a schematic diagram of the structure of a display panel according to another embodiment of the present disclosure.

[0024] Figure 4 This is a top perspective view of a portion of the structure of a display panel according to an embodiment of the present disclosure.

[0025] Figure 5 This is a flowchart of a display driving method according to an embodiment of the present disclosure.

[0026] Figure 6 yes Figure 5 The diagram shows a signal waveform of one of the driving methods.

[0027] Figure 7 This is a circuit diagram of the pixel circuit according to an embodiment of the present disclosure.

[0028] Figure 8 yes Figure 7 The flowchart shows the driving method of the pixel circuit.

[0029] Figure 9 yes Figure 7 The signal waveform diagram of the pixel circuit shown.

[0030] Figure 10 yes Figure 7 Another signal waveform diagram of the pixel circuit shown. Detailed Implementation

[0031] The present disclosure will be further described below with reference to the embodiments shown in the accompanying drawings.

[0032] Figure 2 This is a schematic diagram of the structure of a display panel according to an embodiment of the present disclosure. Figure 3 This is a schematic diagram of the structure of a display panel according to another embodiment of the present disclosure. Figure 4 This is a top perspective view of a portion of the structure of a display panel according to an embodiment of the present disclosure.

[0033] refer to Figures 2 to 4 The present disclosure provides a display panel including: a first substrate 1, a second substrate 2 and a pixel wall 3; the first substrate 1 and the second substrate 2 are disposed opposite to each other, and the pixel wall 3 is disposed between the first substrate 1 and the second substrate 2 to form a plurality of closed pixel spaces, the pixel spaces are filled with transparent liquid, and black charged particles B or colored charged particles are dispersed in the transparent liquid.

[0034] In some embodiments, the material of the pixel wall 3 includes: organic resin.

[0035] In some embodiments, the material of the transparent liquid includes: diethylene glycol methyl ethyl ether.

[0036] In some embodiments, the material of the black charged particle B includes carbon. The surface of the carbon nanoparticles has a layer of potential ions, which adsorb electrons or positive ions in the transparent liquid through electrostatic interaction, thereby making the carbon nanoparticles positively or negatively charged.

[0037] In some embodiments, the diameter of the carbon nanoparticles is in the range of 300 nm to 500 nm.

[0038] In some embodiments, the first substrate 1 includes a glass substrate (not shown) and a driving circuit layer disposed on the glass substrate. Figure 2 and Figure 3 Only the pixel electrode 11, common electrode 12, and reflective electrode 13 in the driving circuit layer are shown. The driving circuit layer contains multi-layer wiring and multiple pixel circuits. Each pixel circuit controls the voltage of one pixel electrode 11. The multi-layer wiring includes power lines, gate lines, and data lines, etc.

[0039] The first substrate 1 includes: a plurality of pixel electrodes 11, at least one common electrode 12, and at least one reflective electrode 13. The plurality of pixel electrodes 11 are disposed opposite to a plurality of enclosed pixel spaces in a one-to-one correspondence. The at least one common electrode 12 has an overlapping area with the pixel space, and the at least one reflective electrode 13 has an overlapping area with the pixel space. The overlapping areas of any pixel space and the common electrode 12, and the overlapping areas of any pixel space and its corresponding pixel electrode 11 are spaced apart in a set direction, which is a direction parallel to the display panel. The overlapping area of ​​any pixel space and the reflective electrode 13 is located at least between the overlapping areas of any pixel space and the common electrode 12, and the overlapping areas of any pixel space and its corresponding pixel electrode 11.

[0040] exist Figure 4 In the illustrated embodiment, each column of pixel space is disposed opposite to a common electrode 12. In other embodiments, the common electrodes 12 in the display panel are connected as one unit. In still other embodiments, the pixel spaces are disposed opposite to the common electrodes 12 in a one-to-one correspondence.

[0041] exist Figure 4 In the illustrated embodiment, the pixel spaces are arranged opposite to the reflective electrodes 13 in a one-to-one correspondence. In other embodiments, the reflective electrodes 13 in the display panel are integrated as a single unit.

[0042] This disclosure does not limit the position of the pixel electrode 11, the common electrode 12, and the reflective electrode 13 in the electrode layer. In some embodiments, the pixel electrode 11, the common electrode 12, and the reflective electrode 13 are disposed in the same layer. In other embodiments, at least two of the pixel electrode 11, the common electrode 12, and the reflective electrode 13 are located in different electrode layers.

[0043] In some embodiments, the material of the reflective electrode 13 includes silver.

[0044] In some embodiments, the materials of the pixel electrode 11 and the common electrode 12 include at least one of copper, aluminum, molybdenum, titanium, chromium, and tungsten.

[0045] refer to Figure 2 and Figure 3 When the voltage difference applied between the pixel electrode 11 and the common electrode 12 is large enough (arrows in the figure represent electric field lines), black charged particles B or colored charged particles will be attracted to the vicinity of the common electrode 12 or the pixel electrode 11, thus making the pixel space corresponding to the pixel electrode 11 bright. When the voltage difference applied between the pixel electrode 11 and the common electrode 12 is small enough, the black charged particles B or colored charged particles are uniformly dispersed in the pixel space, thus making the pixel space corresponding to the pixel electrode 11 dark.

[0046] Thus, this disclosure provides a new type of display panel. A driving method for this display panel will be described later.

[0047] In some embodiments, reference Figure 2 The transparent liquid contains black charged particles B. The first substrate 1 also includes multiple color filter layers CF, which are arranged in a one-to-one correspondence with multiple pixel spaces. The color filter layers CF are located on the side of the reflective electrode 13 near the second substrate 2.

[0048] In some embodiments, reference Figure 3 The transparent liquid contains black charged particles B. The second substrate 2 includes multiple color filter layers CF, which are arranged in a one-to-one correspondence with multiple pixel spaces.

[0049] In some embodiments, the second substrate 2 includes a black matrix 21, wherein the opening regions of the black matrix 21 are disposed opposite to the pixel spaces in a one-to-one correspondence.

[0050] Specifically, the second substrate 2 also includes a glass substrate (not shown). The black matrix 21 is disposed on the surface of the glass substrate near the side of the second substrate 2.

[0051] In some embodiments, combined with Figure 4 The pixels are arranged in an array, and the orientation is set as one of the arrangement directions of the pixel space.

[0052] In some embodiments, the reflective electrode 13 is suspended in the air.

[0053] refer to Figure 5 The present disclosure provides a display driving method for driving the aforementioned display panel. The display driving method includes:

[0054] Step S100: Apply a common voltage to the common electrode 12, and alternately apply a first voltage and a second voltage to the pixel electrode 11. One of the first voltage and the second voltage is greater than the common voltage, and the other is less than the common voltage. The absolute value of the difference between the first voltage and the common voltage is greater than the absolute value of the difference between the second voltage and the common voltage. The duty cycle of the first voltage provided to the pixel electrode 11 corresponding to the pixel space is controlled according to the gray level to be displayed in the pixel space.

[0055] Combination Figure 6 A constant common voltage is applied to the common electrode 12. The absolute value of the difference between the first voltage and the common voltage is greater than the absolute value of the difference between the second voltage and the common voltage.

[0056] In one embodiment, the common voltage is -1V, the first voltage is 5V, and the second voltage is -2V. A higher duty cycle of the first voltage causes the black charged particles B or the colored charged particles to tend to concentrate on one side of the pixel space, resulting in a larger grayscale level in the pixel space. A lower duty cycle of the first voltage causes the black charged particles B or the colored charged particles to tend to be more uniformly dispersed within the pixel space, resulting in a lower grayscale level in the pixel space.

[0057] The absolute value of the difference between the second voltage and the common voltage is relatively small, which is conducive to accelerating the transformation of black charged particles B or colored charged particles into a uniformly dispersed state, and will not attract black charged particles B or colored charged particles to the other side of the pixel space.

[0058] Based on the above structure, the grayscale of the pixel space can be controlled by adjusting the time percentage of the first voltage. The adjustment precision of the time percentage of the first voltage can be designed according to actual needs, which greatly improves the number of grayscale levels displayed.

[0059] Based on the same inventive concept as the foregoing embodiments, and referring to... Figure 7 The embodiments of this disclosure also provide a pixel circuit, which includes a writing circuit C100 and a conversion circuit C200. The writing circuit C100 is used to write display data voltage Data to a storage node. The conversion circuit C200 is used to output a square wave signal Out with a duty cycle corresponding to the voltage value of the storage node, wherein the duty cycle of the square wave signal Out is positively or negatively correlated with the voltage value of the storage node.

[0060] The conversion circuit C200 maps the display data voltage Data to the duty cycle of the square wave signal Out, thereby adjusting the brightness (i.e., grayscale) of the pixel space.

[0061] In some embodiments, reference Figure 7 The conversion circuit C200 includes a first transistor T1, a second transistor T2, and a third transistor T3. The gate of the first transistor T1 is connected to the first source-drain terminal of the third transistor T3, the drain of the first transistor T1 is connected to the first power supply terminal VDD1, and the source of the first transistor T1 is connected to the source of the second transistor T2 and is used to output a square wave signal Out. The drain and gate of the second transistor T2 are both connected to the second power supply terminal VDD2. The polarities of the first transistor T1 and the second transistor T2 are opposite. The gate of the third transistor is connected to the storage node, and the second source-drain terminal of the third transistor T3 receives a scan signal Sweep, which has a period of monotonically changing time.

[0062] In some embodiments, reference Figure 7The write circuit C100 includes: a fourth transistor T4 and a storage capacitor C1. The gate of the fourth transistor T4 receives the gate control signal Gate. The first source and drain of the fourth transistor T4 receive the data voltage Data. The second source and drain of the fourth transistor T4 are connected to the storage node N and the first terminal of the storage capacitor C1. The second terminal of the storage capacitor C1 is connected to a fixed voltage terminal (specifically, the second power supply terminal VDD2).

[0063] Based on the same inventive concept, and referring to Figure 8 The embodiments of this disclosure provide a driving method for the aforementioned pixel circuit, comprising:

[0064] Step S101: During the data writing stage, the display data voltage (Data) is written to the storage node;

[0065] Step S102: In the grayscale control stage, a square wave signal Out with a duty cycle corresponding to the voltage value of the storage node is output, wherein the duty cycle of the square wave signal Out is positively or negatively correlated with the display data voltage Data.

[0066] refer to Figure 9 At the data writing node, data voltages are written line by line to the storage nodes of each pixel circuit.

[0067] During the grayscale adjustment stage, the value of the displayed data voltage Data is mapped to the duty cycle of the square wave signal Out.

[0068] Figure 9 In the embodiment shown, the grayscale modulation stage includes an effective emission period within one frame period.

[0069] exist Figure 10 In the embodiment shown, the grayscale control stage includes multiple effective emission periods within one frame period.

[0070] Based on the same inventive concept, embodiments of this disclosure also include a display device, comprising: the aforementioned display panel.

[0071] Display devices include, for example, display modules, monitors, mobile phones, tablets, e-books, learning machines, and any other products or components with display functions.

[0072] In some embodiments, the display panel integrates the aforementioned pixel circuit, wherein each pixel circuit corresponds to a pixel electrode 11, and the pixel circuit provides a square wave signal Out to the corresponding pixel electrode 11.

[0073] The various embodiments in this disclosure are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0074] The scope of protection of this disclosure is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its scope and spirit. If such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, then the intent of this disclosure also includes such modifications and variations.

Claims

1. A display panel, characterized in that, include: A first substrate, a second substrate, and a pixel wall; the first substrate and the second substrate are disposed opposite to each other, and the pixel wall is disposed between the first substrate and the second substrate to form a plurality of closed pixel spaces, the pixel spaces are filled with transparent liquid, and black charged particles or colored charged particles are dispersed in the transparent liquid; The first substrate includes: a plurality of pixel electrodes, at least one common electrode, and at least one reflective electrode. The at least one pixel electrode, the at least one reflective electrode, and the at least one common electrode are arranged sequentially at intervals along a predetermined direction. The plurality of pixel electrodes are arranged opposite to the plurality of enclosed pixel spaces in a one-to-one correspondence. The at least one common electrode and the pixel space have an overlapping area. The at least one reflective electrode and the pixel space have an overlapping area. The overlapping areas of any pixel space and the common electrode, and the overlapping areas of any pixel space and its corresponding pixel electrode are spaced apart in a predetermined direction. The predetermined direction is a direction parallel to the display panel. The overlapping area of ​​any pixel space and the reflective electrode is located at least between the overlapping areas of any pixel space and the common electrode, and the overlapping areas of any pixel space and its corresponding pixel electrode. The pixel electrode is used to alternately apply different first voltages and second voltages; the common electrode is used to apply a common voltage; one of the first voltage and the second voltage is greater than the common voltage, and the other is less than the common voltage, and the absolute value of the difference between the first voltage and the common voltage is greater than the absolute value of the difference between the second voltage and the common voltage, which is beneficial for black charged particles or colored charged particles to accelerate into a uniformly dispersed state; wherein, the duty cycle of the first voltage provided to the pixel electrode corresponding to the pixel space is controlled according to the grayscale to be displayed in the pixel space.

2. The display panel according to claim 1, characterized in that, The transparent liquid contains dispersed black charged particles. The first substrate further includes multiple color filter layers, which are disposed opposite to the multiple pixel spaces in a one-to-one correspondence. The color filter layers are located on the side of the reflective electrode closer to the second substrate.

3. The display panel according to claim 1, characterized in that, The transparent liquid contains dispersed black charged particles, and the second substrate includes multiple color filter layers, which are disposed opposite to the multiple pixel spaces in a one-to-one correspondence.

4. The display panel according to claim 1, characterized in that, The second substrate includes a black matrix, wherein the opening regions of the black matrix are disposed opposite to the pixel space in a one-to-one correspondence.

5. The display panel according to claim 1, characterized in that, The pixel space is arranged in an array, and the set direction is one of the arrangement directions of the pixel space.

6. The display panel according to claim 1, characterized in that, The reflective electrode is suspended in the air.

7. A display driving method, characterized in that, The display driving method for driving a display panel according to any one of claims 1 to 6 includes: A common voltage is applied to the common electrode, and a first voltage and a second voltage are alternately applied to the pixel electrode, wherein one of the first voltage and the second voltage is greater than the common voltage and the other is less than the common voltage, and the absolute value of the difference between the first voltage and the common voltage is greater than the absolute value of the difference between the second voltage and the common voltage, wherein the duty cycle of the first voltage provided to the pixel electrode corresponding to the pixel space is controlled according to the gray level to be displayed in the pixel space.

8. A pixel circuit, characterized in that, The pixel circuit, applied to any one of claims 1 to 6, comprises: a writing circuit and a conversion circuit, wherein the writing circuit is used to write display data voltage to a storage node, and the conversion circuit is used to output a square wave signal with a duty cycle corresponding to the voltage value of the storage node, wherein the duty cycle of the square wave signal is positively or negatively correlated with the voltage value of the storage node.

9. The pixel circuit according to claim 8, characterized in that, The conversion circuit includes a first transistor, a second transistor, and a third transistor. The gate of the first transistor is connected to the first source-drain terminal of the third transistor, the drain of the first transistor is connected to a first power supply terminal, and the source of the first transistor is connected to the source of the second transistor and is used to output the square wave signal. The drain and gate of the second transistor are both connected to a second power supply terminal, and the polarities of the first transistor and the second transistor are opposite. The gate of the third transistor is connected to the storage node, and the second source-drain terminal of the third transistor receives a scan signal, which has a time interval that changes monotonically with time.

10. The pixel circuit according to claim 8, characterized in that, The write circuit includes a fourth transistor and a storage capacitor. The gate of the fourth transistor receives a gate control signal, the first source and drain of the fourth transistor receive a data voltage, the second source and drain of the fourth transistor are connected to the storage node and the first terminal of the storage capacitor, and the second terminal of the storage capacitor is connected to a fixed voltage terminal.

11. A driving method for a pixel circuit according to any one of claims 8 to 10, characterized in that, include: During the data writing phase, the displayed data voltage is written to the storage node; During the grayscale control stage, a square wave signal with a duty cycle corresponding to the voltage value of the storage node is output, wherein the duty cycle of the square wave signal is positively or negatively correlated with the voltage of the storage node.

12. A display device, characterized in that, include: The display panel according to any one of claims 1 to 6.

13. The display device according to claim 12, characterized in that, The display panel integrates a pixel circuit according to any one of claims 8 to 10, wherein the pixel circuit corresponds one-to-one with the pixel electrode, and the pixel circuit provides the square wave signal to the corresponding pixel electrode.

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