Display panel and electronic device
By introducing a control module and a PWM module into the display panel, the anode voltage of the light-emitting device can be quickly reset, solving the problems of slow brightness response and low contrast caused by self-discharge of the sub-pixel light-emitting device, thus improving the display quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YONGJIANG LAB
- Filing Date
- 2024-12-11
- Publication Date
- 2026-06-12
Smart Images
Figure CN122201155A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of microdisplays, and more particularly to a display panel and electronic device. Background Technology
[0002] With the continuous development of display technology, people's requirements for display panels in terms of image quality, color accuracy, and response speed are increasing. In the field of modern display panel technology, pixel structure and its control methods have become key factors in achieving high-quality displays. Currently, display panels are generally composed of a matrix of numerous pixels. To achieve full-color display, each pixel can contain multiple sub-pixels. By utilizing the different colors displayed by each sub-pixel and controlling the state of the sub-pixels, rich colors can be synthesized to achieve image display.
[0003] Currently, the sub-pixels are controlled by a current mirror circuit via a row scan signal. The row scan signal scans each sub-pixel line by line, and the corresponding current mirror circuit activates when a sub-pixel is selected. The current mirror circuit replicates or scales the current proportionally to provide driving current for the light-emitting devices in the sub-pixel, precisely adjusting the brightness to display accurate colors and grayscale levels. However, when the light-emitting devices in the sub-pixel emit light, the anode potential drops slowly due to self-discharge, and the voltage cannot be immediately turned off. This results in a slow pixel brightness response and low contrast, leading to a slow response speed and image ghosting on the display panel, ultimately resulting in poor display quality.
[0004] Therefore, improving the display quality of display panels is an urgent problem to be solved. Summary of the Invention
[0005] This application provides a display panel and an electronic device to improve the display quality of the display panel.
[0006] In a first aspect, embodiments of this application provide a display panel, the display panel including a plurality of pixels arranged in rows and columns, a control module, and a pulse width modulation (PWM) module, wherein each pixel includes a plurality of sub-pixel circuits and light-emitting devices electrically connected to each of the sub-pixel circuits respectively;
[0007] The control module is used to output a reset control signal to the sub-pixel circuit at the end of the display cycle of the display panel, so as to control the light-emitting device in the sub-pixel circuit to reset quickly and achieve rapid shutdown.
[0008] The PWM module is connected to the control module and the light-emitting device respectively, and can generate PWM signals based on the control commands of the control module to adjust the brightness of the light-emitting device and realize the periodic display of the display panel.
[0009] Secondly, embodiments of this application provide an electronic device, which includes a display panel as described in any one of the first aspects.
[0010] The display panel and electronic device provided in this application embodiment, when the path of the light-emitting device in multiple pixels of the display panel is cut off at the same time, the externally connected control module outputs a reset control signal to the sub-pixel circuit at the cut-off time, so as to reset the anode voltage of the light-emitting device in the sub-pixel circuit, accelerate the speed at which the anode voltage of the light-emitting device drops, thereby improving the brightness response speed and contrast of the display panel, and thus improving the display quality of the display panel. Attached Figure Description
[0011] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0012] Figure 1 This is a schematic diagram of the structure of the display panel provided in this application;
[0013] Figure 2 A schematic diagram of a circuit structure for a sub-pixel provided in this application;
[0014] Figure 3 This application provides a schematic diagram of the operating timing of a display panel.
[0015] Figure 4 A schematic diagram illustrating the operating timing of another display panel provided in this application;
[0016] Figure 5 This is a schematic diagram of the structure of a display panel provided in an embodiment of this application;
[0017] Figure 6 A schematic diagram of another display panel provided in an embodiment of this application.
[0018] Figure 7 This is a schematic diagram of another display panel provided in an embodiment of this application;
[0019] Figure 8 This is a schematic diagram of the working timing of a display panel provided in an embodiment of this application;
[0020] Figure 9 This is a schematic diagram illustrating the operating timing of another display panel provided in an embodiment of this application;
[0021] Figure 10 This is a schematic diagram of another display panel provided in an embodiment of this application;
[0022] Figure 11 This is a schematic diagram of another display panel provided in an embodiment of this application;
[0023] Figure 12 This is a schematic diagram of another display panel provided in an embodiment of this application;
[0024] Figure 13 This is a schematic diagram of another display panel provided in an embodiment of this application;
[0025] Figure 14 This is a schematic diagram of another display panel provided in an embodiment of this application;
[0026] Figure 15 This is a schematic diagram of another display panel provided in an embodiment of this application.
[0027] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation
[0028] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.
[0029] In the field of display technology, display panels display images through pixels. A display panel can include multiple pixels arranged in rows and columns; that is, the pixels in a display panel can be arranged in a matrix form with multiple rows and columns. For each pixel, the pixel can include at least one sub-pixel to achieve different color display effects.
[0030] Taking the display of colors based on the Red-Green-Blue (RGB) color model as an example, the subpixels within a pixel can be arranged in an RGB pattern. For example, a pixel can include red, green, and blue subpixels, arranged sequentially. With this arrangement, various colors can be mixed by adjusting the brightness of each subpixel. For instance, when the red and green subpixels are lit at the same brightness, the human eye perceives yellow. This arrangement is widely used in common display technologies such as Liquid Crystal Displays (LCDs) and Organic Light-Emitting Diodes (OLEDs).
[0031] In addition, the colors displayed by pixels can also be based on other color models, such as the Red-Green-Blue-White (RGBW) color model. In this case, the arrangement of subpixels in the pixel is the same as that of the color model.
[0032] Figure 1 This is a schematic diagram of the structure of the display panel provided in this application. Figure 1 As shown, this display panel is described using a line scanning circuit as an example.
[0033] In such Figure 1 The display panel shown includes multiple sub-pixels arranged in a matrix (for ease of explanation, Figure 1 The image only shows a 2×2 subpixel array portion of the display panel. It should be understood that this 2×2 subpixel array is only a part of the subpixel array of the display panel, namely subpixel 1_1, subpixel 1_2, subpixel 2_1, and subpixel 2_2 (each subpixel includes a corresponding light-emitting device). This matrix arrangement helps to precisely control the state of each subpixel, thereby achieving high-resolution image display.
[0034] For each row of sub-pixels in the array, the scanning process is performed using the same scanning signal output module (sub-pixels 1_1 and 1_2 in the first row are scanned using scanning signal 1, and sub-pixels 2_1 and 2_2 in the second row are scanned using scanning signal 2). The scanning signal output module provides scanning signals row by row in a predetermined order. For example, starting from the first row of the sub-pixel array, the scanning signal output module outputs a specific scanning signal with a certain voltage and frequency. When this scanning signal reaches the sub-pixel in that row, it triggers operations such as transistor conduction, capacitor charging initialization, and data signal writing in the circuit of that row's sub-pixel, preparing for subsequent charging and light emission of the sub-pixel. Each row of sub-pixels has its corresponding scanning signal to ensure that each row of sub-pixels is operated on at the appropriate time, avoiding signal interference and confusion.
[0035] For each column of sub-pixels in the array, they are charged through the same reference current module (i.e., sub-pixels 1_1 and 2_1 in the first column are charged through reference current module Ref1, and sub-pixels 1_2 and 2_2 in the second column are charged through reference current module Ref2). Each column of sub-pixels shares a single reference current module, which provides a stable current. The current provided by the reference current module is precisely designed to meet the charging requirements of the sub-pixels.
[0036] Each sub-pixel includes a light-emitting device, which may be, for example, a light-emitting diode (LED) or an organic light-emitting diode (OLED), and this application does not limit the application to such devices.
[0037] During display on the display panel, the scan signal output module turns on row by row, scanning the sub-pixels in the corresponding row. During scanning, the reference current module (e.g., Ref1 and Ref2 in the diagram) corresponding to the column of each sub-pixel in that row charges the sub-pixel, enabling it to emit light after the light-emitting device's path is subsequently turned on. This charging process stores electrical energy in components such as capacitors inside the sub-pixel. Once charging is complete, if the sub-pixel needs to emit light, the stored electrical energy can be used to drive the light-emitting device to emit light by turning on the path of the light-emitting device within the sub-pixel.
[0038] For ease of understanding, the following is... Figure 1 The circuit structure of each sub-pixel in the diagram will be introduced. Figure 2 This is a schematic diagram of a circuit structure for a sub-pixel provided in this application. Figure 2 As shown, this sub-pixel includes a current mirror circuit and a light-emitting device. Figure 2 This paper takes a P-type metal-oxide-semiconductor (PMOS) current mirror circuit as an example for introduction. The circuit of this sub-pixel includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a capacitor.
[0039] In this configuration, the gate of the third switch is connected to the output of the scan signal output module, its source is connected to the output of the reference current module and the source of the fourth switch, and its drain is connected to the drain of the first switch. The gate of the fourth switch is connected to the gate of the third switch and the output of the scan signal output module. The source of the first switch is connected to the first terminal of the capacitor, the power supply terminal, and the drain of the second switch, while its gate is connected to the second terminal of the capacitor, the drain of the fourth switch, and the gate of the second switch. The source of the second switch is connected to the drain of the fifth switch. The source of the fifth switch is connected to the anode of the light-emitting device, and its gate is connected to the pulse-width modulation (PMW) module. The cathode of the light-emitting device is connected to the Earth Low Voltage Signal Source (ELVSS).
[0040] When the scan signal output module outputs a scan signal, the third and fourth switching transistors are turned on, allowing the reference current module to charge the capacitor in the current mirror circuit. The fifth switching transistor turns on or off the path between the current mirror circuit and the light-emitting device according to the enable signal output by the PWM module, thereby controlling the current mirror circuit to drive the light-emitting device to emit light or turn off.
[0041] when Figure 1 Each sub-pixel in the sub-pixel array shown is Figure 2 When the circuit structure shown is used, the working state of the sub-pixels in the display panel can be divided into a scanning stage and a light-emitting stage. Figure 3 This is a schematic diagram illustrating the operating timing of a display panel provided in this application. (The preceding text appears to be incomplete and requires further context.) Figure 1 and Figure 2 On the basis of, such as Figure 3 As shown, during the scanning phase, the enable signal output by the PWM module is a level 1 that turns off the path between the current mirror circuit and the light-emitting device. Each scanning signal scans the sub-pixel in the row corresponding to the scanning signal in the array, and charges the sub-pixel in the row through the reference current module during scanning.
[0042] After the display panel completes line-by-line scanning, it enters the light-emitting stage. At this time, the enable signal output by the PWM module is a level 2 that turns on the path between the current mirror circuit and the light-emitting device, so that each sub-pixel can drive the light-emitting device corresponding to that sub-pixel to emit light based on the current mirror module within that sub-pixel that has completed charging.
[0043] When the enable signal output by the PWM module changes from level 2 back to level 1, the path between the current mirror module and the light-emitting device is cut off, so that the light-emitting device is turned off.
[0044] However, when the enable signal output by the PWM module changes from level 2 back to level 1, cutting off the path between the current mirror module and the light-emitting device, the light-emitting device is affected by its self-discharge phenomenon. The anode voltage decreases slowly and cannot immediately drop to the voltage required for shutdown. This manifests visually as a slow brightness response and low contrast on the display panel, thus reducing its display quality.
[0045] For example, Figure 4 A timing diagram illustrating the operation of another display panel provided in this application. Figure 4 As shown, during the light-emitting stage, when the enable signals output by the PWM module change from level 2 to level 1 to extinguish the corresponding light-emitting devices, the enable signals immediately change from level 2 to level 1, while the anode voltage of the corresponding light-emitting device decreases slowly, corresponding to its anode current (e.g., Figure 4The anode current of the light-emitting device corresponding to sub-pixel 1_1 (I_Va1_1) also decreases slowly, causing the light-emitting device to fail to turn off immediately.
[0046] Furthermore, since the current mirror circuit is used to modulate the operating current of the light-emitting device, the grayscale modulation of the light-emitting device is determined by the enable signal output by the PWM module of the sub-pixel. When the path between the current mirror module and the light-emitting device is cut off, the light-emitting device is affected by its self-discharge phenomenon, which leads to a slow change in current in the light-emitting device. This results in a deviation in the grayscale brightness control of the sub-pixel, further affecting the low display quality of the display panel.
[0047] In view of this, this application provides a display panel in which, when the path of the light-emitting device in multiple pixels of the display panel is cut off at the same time, an externally connected control module outputs a reset control signal to the sub-pixel circuit at the cut-off time, so as to reset the anode voltage of the light-emitting device in the sub-pixel circuit, accelerate the speed at which the anode voltage of the light-emitting device drops, thereby improving the brightness response speed and contrast of the display panel, and thus improving the display quality of the display panel.
[0048] Figure 5 This is a schematic diagram of the structure of a display panel provided in an embodiment of this application. Figure 5 As shown, the display panel includes multiple pixels arranged in rows and columns, a control module, and a PWM module. Each pixel includes multiple sub-pixel circuits and light-emitting devices electrically connected to each sub-pixel circuit.
[0049] The control module is used to output a reset control signal to the sub-pixel circuit at the end of the display cycle of the display panel, so as to control the light-emitting device in the sub-pixel circuit to quickly reset and achieve rapid shutdown.
[0050] The PWM module is connected to the control module and the light-emitting device respectively, and can generate PWM signals based on the control commands of the control module to adjust the brightness of the light-emitting device and realize the periodic display of the display panel.
[0051] Specifically, the control terminal of the PWM module is connected to the second output terminal of the control module, the first terminal is connected to the anode of the light-emitting device, and the second terminal is connected to the power supply terminal of the light-emitting device.
[0052] The control module can be, for example, a processor, microprocessor, or control circuit of the display panel; any circuit or electronic component capable of performing its control function is acceptable, and this application does not impose any restrictions. The reset control signal is used to provide a negative voltage to the light-emitting device when the light-emitting device cuts off the path, enabling rapid discharge of the accumulated charge on the anode of the light-emitting device, thereby accelerating the extinguishing speed of the light-emitting device and completing the reset of the light-emitting device.
[0053] Optionally, the control module can control the reset control signal to maintain a first level based on the scanning signal of the display panel through timing coordination, so as to control whether the sub-pixel circuit resets the light-emitting device. For example, the control module can determine the time of the scanning phase when scanning the display panel with the scanning signal, and perform timing coordination based on the time of the scanning phase, so as to control the level of the reset control signal when the display panel needs to be reset and when it does not need to be reset. For example, when the display panel needs to be reset, the reset control signal can be controlled to maintain a first level, so as to control the sub-pixel circuit to reset the light-emitting device before the start of the display cycle and at the end of the display cycle. When the display panel does not need to be reset, the reset control signal can be switched to a second level to stop the reset. The first level can be lower than the second level, or the first level can be higher than the second level. The correlation between the level of the reset control signal and the indication of whether the sub-pixel circuit performs a reset behavior can be set according to actual needs, and this application does not limit it.
[0054] Alternatively, the control module can adjust whether to output a reset control signal through timing coordination to control whether the sub-pixel circuit resets the light-emitting device. For example, the control module can output a reset control signal when a reset is required and stop outputting the reset control signal when a reset is not required, thereby controlling whether the sub-pixel circuit resets the light-emitting device.
[0055] Taking the control module's timing coordination to adjust the level of the reset control signal to control whether the sub-pixel circuit resets the light-emitting device as an example, this reset control signal is synchronized with the control signal that controls the light-emitting device to light up or turn off (i.e., the enable signal output by the PWM module). That is, the timing of the reset control signal is coordinated according to the timing of this control signal to determine its own timing. The phase of the reset control signal and the control signal can be in phase or out of phase. This reset control signal can be used to simultaneously reset the light-emitting devices in multiple pixels.
[0056] Specifically, when the path to the light-emitting device is cut off, the control signal disconnects the path, and simultaneously, the reset control signal output by the control module controls the sub-pixel circuit to output a negative voltage to the anode of the light-emitting device, which can quickly discharge the accumulated charge on the anode, thereby accelerating the extinguishing speed of the light-emitting device and completing the reset of the light-emitting device. For example, assuming the anode potential of the light-emitting device is between 1V and 1.2V when emitting light, the negative voltage output by the sub-pixel circuit to the anode of the light-emitting device, which can quickly extinguish the light-emitting device, could be, for example, -0.7V. This negative voltage can quickly discharge the accumulated charge on the anode of the light-emitting device, thereby accelerating the extinguishing speed of the light-emitting device.
[0057] Optionally, the sub-pixel circuit may include, for example, the circuit described above. Figure 2 The current mirror circuit shown may also include other pixel circuits that control the conduction or disconnection of the light-emitting device by the enable signal output by the PWM module, and this application does not limit this.
[0058] In one possible implementation, the control module is also used to output a reset control signal to the sub-pixel circuit before the light-emitting devices of all pixels in the display panel emit light, so as to reset the light-emitting devices of the sub-pixel circuit, to ensure that the light-emitting devices of each pixel remain in an off state before the control signal controls the light emission, and to prevent the light-emitting devices from emitting light prematurely.
[0059] Optionally, the reset control signal is a global reset control signal, and all sub-pixel circuits in the display panel are in a uniform shutdown mode. That is, the reset control signal can reset the light-emitting devices corresponding to all sub-pixel circuits in the display panel; that is, for all sub-pixel circuits in the display panel, the corresponding reset control signal is the same. The uniform shutdown mode for all sub-pixel circuits in the display panel means that the turn-off time of all sub-pixel circuits in the display panel is the same.
[0060] This application provides a display panel in which, when the path of the light-emitting device in multiple pixels of the display panel is cut off, an externally connected control module outputs a reset control signal to the sub-pixel circuit when the path of the light-emitting device is cut off, so that the sub-pixel circuit resets the anode voltage of the light-emitting device, quickly discharges the accumulated charge on the anode of the light-emitting device, and accelerates the extinguishing speed of the light-emitting device, thereby improving the brightness response speed and contrast of the display panel, and thus improving the display quality of the display panel.
[0061] The internal structure of the sub-pixel circuit will be described in detail below.
[0062] Figure 6 This is a schematic diagram of another display panel structure provided in an embodiment of this application. (See attached diagram.) Figure 6 As shown, the sub-pixel circuit includes a reset module.
[0063] The input terminal of the reset module is connected to the first output terminal of the control module, the output terminal is connected to the anode of the light-emitting device, and the cathode of the light-emitting device is connected to the ELVSS.
[0064] The reset module is used to output a reset signal to the light-emitting device according to the reset control signal output by the control module. The reset signal is used to reset the anode of the light-emitting device, thereby realizing the rapid turn-off of the light-emitting device.
[0065] The reset signal is the one mentioned above. Figure 5 The corresponding embodiment describes the use of a negative voltage to reset the light-emitting device. The reset module determines whether to output a reset signal based on the level of the reset control signal output by the control module. When the level of the reset control signal indicates that the reset module should output a reset signal, the reset module outputs the reset signal to the anode of the light-emitting device, so that the anode of the light-emitting device can be reset according to the reset signal.
[0066] The following section provides a detailed introduction to the aforementioned PWM module and the relationship between the control module and the PWM module.
[0067] This PWM module controls the illumination and extinguishing of a light-emitting device (LED) based on its illumination duration. The PWM module can switch the power supply circuit of the LED on or off according to the illumination duration to control its illumination. For example, at the beginning of the illumination duration, the PWM module controls the power supply circuit to be turned on, allowing the power supply terminal to supply power to the LED, causing it to illuminate. At the end of the illumination duration (i.e., when the path to the LED is cut off), the PWM module controls the power supply circuit to be turned off, stopping the power supply terminal from supplying power to the LED, causing it to extinguish.
[0068] For example, continuing with the aforementioned Figure 2 Taking the PWM module shown as an example, the PWM module outputs pulses of a specific period according to the light emission time of the light-emitting device, which are used as an enable signal to control the opening and closing of the fifth switch, thereby controlling the conduction and disconnection of the power supply circuit of the light-emitting device.
[0069] Alternatively, the PWM module can be any other module capable of outputting an enable signal. Based on the light-emitting time of the light-emitting device, at the beginning of the light-emitting time, an enable signal is output to control the power supply circuit of the light-emitting device to be turned on. The switch closes according to the enable signal, so that the power supply terminal supplies power to the light-emitting device, causing the light-emitting device to emit light. When the light-emitting device's path is cut off, an enable signal is output to control the power supply circuit of the light-emitting device to be turned off. The switch closes according to the enable signal, so that the power supply terminal stops supplying power to the light-emitting device, causing the light-emitting device to turn off.
[0070] In one possible implementation, the emission time is sent from the control module to the PWM module. In this implementation, the control module is also used to acquire the emission time of the light-emitting device and send it to the PWM module. This emission time can be obtained externally by the control module, for example, by determining the emission time of the light-emitting device corresponding to each sub-pixel within each pixel based on the emission requirements of each pixel corresponding to the received image information. The control module can synchronize this emission time with the PWM module via a pin connected to the PWM module. After receiving the emission time, the PWM module controls the light-emitting device to emit or extinguish according to the emission time.
[0071] In another possible implementation, the emission time is sent to the PWM module by a module other than the control module. In this implementation, the control module is also used to obtain the emission time from the PWM module. This emission time can be, for example, obtained externally by the PWM module (e.g., received). The PWM module controls the emission of the light-emitting device to light up or turn off based on the received emission time of the light-emitting device corresponding to the sub-pixel circuit. The control module can obtain this emission time from the PWM module through a pin connected to the PWM module. Based on the obtained emission time, the control module determines how to output a reset control signal according to the aforementioned method to reset the light-emitting device.
[0072] In any of the above implementation methods, for example, taking the reset control signal controlling the reset module to stop outputting the reset signal with a low level and the reset control signal controlling the reset module to output the reset signal with a high level as an example, the explanation of how the reset control signal controls the reset module to reset the light-emitting device is provided.
[0073] Before any light-emitting device electrically connected to the sub-pixel circuit begins to emit light, the reset control signal changes from low to high. The reset module stops outputting the reset signal when the reset control signal is high. Since the reset signal is essentially a negative voltage, if the reset module does not stop outputting the reset signal before the light-emitting device emits light, it will affect the light emission of the light-emitting device, for example, causing the grayscale of the light-emitting device to differ from the expected grayscale, or the brightness to be lower than the expected brightness. Therefore, before any light-emitting device in any pixel of the display panel begins to emit light, the control module needs to change the reset control signal from low to high to stop the reset module from outputting the reset signal, thus avoiding any impact on the light emission of the light-emitting device.
[0074] When the path to the light-emitting device is cut off, the reset control signal changes from high to low, and the reset module outputs a reset signal when the reset control signal is low. When the path to the light-emitting device is cut off, all light-emitting devices in the display panel need to be immediately turned off. The control module controls the reset module to output a reset signal by changing the output reset control signal from high to low. This negative voltage of the reset signal accelerates the reduction of the anode voltage of the light-emitting device to the potential range corresponding to the device being off, thereby shortening the time it takes for the light-emitting device to turn off, reducing the problem of not being able to turn off immediately due to self-discharge of the light-emitting device, and improving the brightness response speed and contrast of the display panel.
[0075] Continuing with the example where the reset control signal controls the reset module to stop outputting the reset signal at a low level, and the reset control signal controls the reset module to output the reset signal at a high level. Figure 7 This is a schematic diagram of another display panel provided in an embodiment of this application. Figure 7 As shown, the reset module includes: a first switch and a reset power supply submodule.
[0076] The first terminal of the first switch is connected to the output terminal of the control module, the second terminal is connected to the anode of the light-emitting device, and the third terminal is connected to the output terminal of the reset power supply submodule.
[0077] The reset power supply submodule is used to output a reset signal.
[0078] The first switch is used to connect the reset power supply submodule and the light-emitting device when the reset control signal changes from high level to low level, and to connect the reset power supply submodule and the light-emitting device when the reset control signal changes from low level to high level.
[0079] The reset power supply submodule can be, for example, a linear regulated power supply module, a switching power supply module, a charge pump power supply module, or any other power supply module capable of outputting a negative voltage. For instance, taking a charge pump power supply module as the reset power supply submodule, the charge pump power supply module can utilize an internal capacitor array and switching network to achieve voltage conversion. The charge pump power supply module periodically switches the switches, charging and discharging the capacitors to gradually increase or decrease the voltage. For example, the charge pump power supply module can employ a cross-coupled capacitor structure, where two sets of capacitors work alternately. When one set of capacitors charges, the other set discharges. By controlling the order in which the capacitors are connected to the input voltage and ground, and utilizing charge transfer between the capacitors, the positive voltage is converted into a negative voltage output.
[0080] The first switch, based on the level shift of the reset control signal output by the control module, either opens or closes the path between the reset power supply submodule and the light-emitting device. When the path between the reset power supply submodule and the light-emitting device is opened, the reset signal output by the reset power supply submodule can reset the anode potential of the light-emitting device; when the path between the reset power supply submodule and the light-emitting device is closed, the reset signal output by the reset power supply submodule can stop resetting the anode potential of the light-emitting device.
[0081] Optionally, the first switch can be an NMOS switch, or a PMOS switch, or a complementary metal-oxide-semiconductor (CMOS) switch. When the first switch is an NMOS switch or a PMOS switch, the first terminal connected to the output terminal of the control module is the gate of the switch.
[0082] During the operation of a light-emitting device, when it begins to emit light, its anode potential gradually rises until it reaches the light-on voltage, at which point the device will emit light. However, if the voltage difference between the anode potential and the light-on voltage is large, the time required for the anode potential to rise is longer, resulting in a slow current response speed. Therefore, to address this issue, the reset power supply submodule in the display panel provided in this application can further improve the current response speed of the light-emitting device when it begins to emit light by controlling the level of the output reset signal.
[0083] Figure 8 This is a schematic diagram illustrating the operating timing of a display panel provided in an embodiment of this application. Figure 8 As shown, before any light-emitting device electrically connected to the sub-pixel circuit starts to emit light (i.e., before the enable signal in the PWM module outputs the control signal to close the loop between the light-emitting device and the power supply terminal, or at the moment when the PWM module outputs the enable signal to close the loop between the light-emitting device and the power supply terminal), the reset signal output by the reset power supply submodule changes from low voltage to high voltage.
[0084] The high voltage is less than the start-up voltage of the light-emitting device, which is the voltage that makes the light-emitting device start to emit light.
[0085] The reset power supply submodule adjusts the anode potential of the light-emitting device before it starts emitting light to a potential with a smaller voltage difference between the current and the start-up voltage by increasing the voltage of the reset signal. This reduces the time it takes for the potential to rise to the start-up voltage when the light-emitting device starts emitting light, thereby accelerating the current response speed of the light-emitting device, improving the start-up speed of the light-emitting device, and thus improving the screen response speed of the display panel.
[0086] After all the light-emitting devices in a pixel emit light, the reset signal output by the reset power supply submodule changes from high voltage to low voltage. Since these devices need to be extinguished when their path is cut off, if the reset signal output by the reset power supply module remains high, it will fail to reach the negative voltage required to reset the anode potential of the light-emitting devices. This results in the devices failing to reset, reducing the rate at which the anode potential of the light-emitting devices drops when their path is cut off, thus decreasing the brightness response time, contrast ratio, and display quality of the display panel. Therefore, after all the light-emitting devices in a pixel emit light, the reset power supply submodule can change the output reset signal back from high voltage to low voltage. This low-level reset signal can meet the requirement of resetting the anode potential of the light-emitting devices when their path is cut off, increasing the rate at which the anode potential of the light-emitting devices drops when their path is cut off, thereby improving the brightness response time, contrast ratio, and display quality of the display panel.
[0087] For example, Figure 9 This is a schematic diagram illustrating the operating timing of another display panel provided in an embodiment of this application. Figure 9 As shown, the reset power supply submodule outputs a low-voltage reset signal before the light-emitting phase (i.e., before the start of the display cycle of the display panel). At the start of the light-emitting phase (i.e., at the start of the display cycle of the display panel), the output reset signal is changed from low voltage to high voltage. Before the PWM module stops outputting the enable signal that closes the loop between the light-emitting device and the power supply terminal (i.e., before the end of the display cycle of the display panel), the reset power supply submodule changes the output reset signal back from high voltage to low voltage again. This is to avoid the high-voltage reset signal affecting the reset of the light-emitting device, allowing the reset signal to quickly discharge the accumulated charge on the anode of the light-emitting device through the low voltage (i.e., the aforementioned negative voltage), thereby improving the extinguishing speed of the light-emitting device.
[0088] In one possible implementation, the reset signal maintains the high voltage until after the start of the lowest grayscale pulse in the display panel and before the end of the display cycle. The lowest grayscale pulse is the pulse output by the PWM module corresponding to grayscale 1 (Gray 1), which is the narrowest pulse among the pulses corresponding to grayscales 0-255. Since the reset signal is a global reset signal used for all sub-pixel circuits in the display panel, and the grayscale of the light-emitting devices corresponding to each sub-pixel circuit is different within the display cycle, the reset signal needs to cover the sub-pixel circuits of all light-emitting devices corresponding to all grayscale levels to satisfy the reset function of all light-emitting devices in the display panel. Therefore, by maintaining the high voltage of the reset signal until after the start of the lowest grayscale pulse in the display panel and before the end of the display cycle, and then switching to a low voltage thereafter, it is ensured that when all light-emitting devices in the display panel are turned off, the high-voltage reset signal can improve the turn-off speed of all light-emitting devices in the display panel.
[0089] In addition, an overvoltage protection module can be set in the sub-pixel circuit to keep the voltage changes in the sub-pixel circuit within the rated voltage range, thus protecting the sub-pixel circuit.
[0090] Figure 10 This is a schematic diagram of another display panel provided in an embodiment of this application. Figure 10 As shown, the sub-pixel circuit also includes: a first overvoltage protection module.
[0091] The first terminal of the first overvoltage protection module is connected to the first terminal of the PWM module, and the second terminal is connected to the anode of the light-emitting device.
[0092] The first overvoltage protection module is used to prevent the devices in the sub-pixel circuit from exceeding the preset operating voltage range (i.e., the rated voltage range).
[0093] When the sub-pixel circuit is a low-voltage sub-pixel circuit, the sub-pixel circuit in the display panel is affected by the reset voltage, causing the anode potential of the light-emitting device to change beyond the low-voltage range corresponding to the sub-pixel circuit. If the anode potential of the light-emitting device changes beyond the low-voltage range corresponding to the sub-pixel circuit, the components (such as switching transistors) within the sub-pixel circuit may be at risk of breakdown. Therefore, this first overvoltage protection module can prevent the components within the sub-pixel circuit from exceeding the preset operating voltage range, thereby ensuring the circuit safety of the sub-pixel circuit and improving the stability of the display panel.
[0094] The first overvoltage protection module may include, for example, a transvoltage resistor. Optionally, the transvoltage resistor may be, for example, a normally open metal-oxide-semiconductor (MOS), a resistor, or a diode, etc., and this application does not limit it in this regard.
[0095] As mentioned above Figure 1 and Figure 2 Taking the row scanning circuit in the middle as an example, Figure 11 This is a schematic diagram of another display panel provided in an embodiment of this application. Figure 11 As shown, the display panel also includes a scan signal output module; the sub-pixel circuit also includes: a current mirror module and a pre-charge module.
[0096] The output terminal of the current mirror module is connected to the second terminal of the PWM module, and the first input terminal is connected to the output terminal of the scan signal output module; the output terminal of the precharge module is connected to the second input terminal of the current mirror module, and the input terminal is connected to the control module.
[0097] A pre-charge module is used to pre-charge the current mirror module before the scanning signal output module scans, so as to improve the charging speed of the current mirror module.
[0098] This current mirror module can be referenced, for example, as described above. Figure 2 The structure and function of the current mirror module shown are not elaborated here.
[0099] During the scanning process of the row scanning circuit, the sub-pixel circuits of different rows need to be scanned row by row by the corresponding scan signal output module to turn on the third and fourth switches of the current mirror module in each sub-pixel circuit of each row. After turning on the third and fourth switches of the current mirror module in the sub-pixel circuit, the reference current module of each column of the sub-pixel circuit charges the capacitor of the current mirror module in its corresponding sub-pixel circuit. If the voltage that the reference current module needs to write to the capacitor has a large voltage difference from the original voltage of the capacitor, the charging time of the reference current module for the capacitor will also be longer, resulting in low charging efficiency and consequently poor display quality of the display panel.
[0100] Therefore, the control module can, based on the time when the scan signal output module outputs the scan signal and the voltage required by the reference current module for the sub-pixel circuit, control the pre-charging module to pre-charge the capacitor of the current mirror module in the sub-pixel circuit before the scan signal output module outputs the scan signal. This reduces the voltage difference between the capacitor and the voltage required by the reference current module, thereby reducing the charging time of the reference current module for the current mirror module, improving charging efficiency, and ultimately improving the display quality of the display panel. For example, the smaller the voltage difference between the pre-charging voltage and the voltage required by the reference current module for the capacitor, the shorter the charging time for the capacitor.
[0101] In one possible implementation, the control module is electrically connected to the scan signal output module and the reference current module. The control module obtains the scan time corresponding to the scan phase from the scan signal output module, and controls the pre-charging time of the pre-charging module for the current mirror module according to the scan time. It also obtains the voltage required by the reference current module to write to the sub-pixel circuit, and controls the pre-charging voltage output by the pre-charging module according to the voltage.
[0102] Another possible implementation involves electrically connecting the control module to the scan signal output module and the reference current module. The control module, based on the scan time corresponding to the scan stage obtained from an external source and the required voltage to be written to the sub-pixel circuit, sends the scan time to the scan signal output module and the required voltage to be written to the sub-pixel circuit to the reference current module. The control module then controls the pre-charging time of the pre-charging module for the current mirror module based on the scan time, and controls the pre-charging voltage output by the pre-charging module based on the voltage.
[0103] Another possible implementation is that the control module can obtain the scan time corresponding to the scan phase from the scan signal output module, and send the voltage required for writing to the sub-pixel circuit obtained from the outside to the reference current module. Alternatively, the control module can send the scan time obtained from the outside to the scan signal output module, and obtain the voltage required for writing to the sub-pixel circuit from the reference current module.
[0104] Figure 12 This is a schematic diagram of another display panel provided in an embodiment of this application. Figure 12 As shown, the pre-charging module includes: a second switch and a pre-charging power supply sub-module.
[0105] The first input terminal of the second switch is connected to the output terminal of the pre-charge power supply submodule, and the second input terminal is connected to the output terminal of the control module.
[0106] The pre-charge power module is used to output the pre-charge voltage.
[0107] The second switch is used to close the path between the pre-charge power supply submodule and the current mirror module when a pre-charge indication signal is received from the control module.
[0108] The control module determines the time to output a pre-charge indication signal to the second switch based on the scan time. Upon receiving the pre-charge indication signal from the control module, the second switch closes the path between the pre-charge power supply submodule and the current mirror module, enabling the pre-charge voltage output by the pre-charge power supply module to pre-charge the capacitor in the current mirror module.
[0109] Optionally, the pre-charge voltage is a preset voltage value. Alternatively, the pre-charge voltage is determined by the pre-charge power module according to the control of the control module. When the pre-charge voltage is determined by the pre-charge power module according to the control of the control module, there is an electrical connection between the control module and the pre-charge power module, and the control module can indicate the pre-charge voltage by sending a pre-charge voltage indication signal to the pre-charge power module. For example, the pre-charge power module can output a pre-charge voltage corresponding to the level of the preset pre-charge voltage indication signal based on the level of the pre-charge voltage indication signal received from the control module and a preset mapping relationship between the level of the pre-charge voltage indication signal and the pre-charge voltage.
[0110] Optionally, the second switch can be an NMOS switch, a PMOS switch, or a CMOS switch. When the first switch is an NMOS switch or a PMOS switch, the first terminal of the second switch connected to the output terminal of the control module is the gate of the switch.
[0111] Figure 13 This is a schematic diagram of another display panel provided in an embodiment of this application. Figure 13 As shown, the sub-pixel circuit also includes a second overvoltage protection module.
[0112] The first end of the second overvoltage protection module is connected to the output end of the reference current module, and the second end is connected to the second input end of the current mirror module.
[0113] The second overvoltage protection module is used to prevent the components in the sub-pixel circuit from exceeding the preset operating voltage range.
[0114] When the sub-pixel circuit operates in the low-voltage domain, the MOSFETs in the sub-pixel circuit are low-voltage transistors. Because the anode voltage of the light-emitting device needs to decrease when the light-emitting device is turned off, the voltage across the anode voltage of the light-emitting device increases with respect to the anode-connected device node. This may cause the voltage to exceed the voltage of the MOSFETs corresponding to these device nodes (e.g., ...). Figure 2 and Figure 11The second overvoltage protection module prevents the components in the sub-pixel circuit from exceeding the preset operating voltage range (e.g., the voltage across any two ends of the MOS transistor does not exceed the maximum withstand voltage of the MOS transistor itself), thus ensuring the circuit safety of the sub-pixel circuit and improving the stability of the display panel.
[0115] The second overvoltage protection module may include, for example, a transvoltage resistor. Optionally, the transvoltage resistor may be, for example, a normally open MOSFET, a resistor, or a diode, etc., and this application does not limit it in this regard.
[0116] For ease of understanding, the following are exemplary schematic diagrams of the sub-pixel circuits in two display panels.
[0117] Figure 14 This is a schematic diagram of another display panel structure provided in an embodiment of this application. The sub-pixel circuit in this display panel uses a common N-contact process, meaning that all switching transistors in the sub-pixel circuit are NMOS switching transistors. Figure 14 As shown, the display panel includes a sub-pixel circuit, a light-emitting device electrically connected to the sub-pixel circuit, a scan signal output module, a reference current module, and a control module. The sub-pixel circuit of the display panel includes: a first NMOS transistor, a second NMOS transistor, a third NMOS transistor, a fourth NMOS transistor, a fifth NMOS transistor, a sixth NMOS transistor, a seventh NMOS transistor, a capacitor, a first resistor, a second resistor, and an enable signal output unit.
[0118] The first NMOS transistor corresponds to the aforementioned Figure 2 or Figure 11 The first switching transistor mentioned above, and the corresponding second, third, fourth, and fifth NMOS transistors, correspond to the aforementioned... Figure 2 or Figure 10 The second, third, fourth, and fifth switching transistors mentioned above. The capacitors correspond to those mentioned earlier. Figure 2 or Figure 11 The capacitor mentioned above. The first resistor is the one described above. Figure 10 The first overvoltage protection module in the middle, the second resistor is as described above. Figure 13 The second overvoltage protection module in the system. The enable signal output unit can be, for example, the aforementioned Figure 2 The PWM module in the module is used to control the light-emitting device to light up and turn off by outputting an enable signal. The sixth NMOS transistor corresponds to the aforementioned... Figure 7 The first switch and the seventh NMOS transistor in the above correspond to the aforementioned Figure 12 The second switch in the system.
[0119] The technical effects of the above modules and devices are similar to those of the display panel in the previous embodiments, and will not be described again here.
[0120] Figure 15 This is a schematic diagram of another display panel structure provided in an embodiment of this application. The sub-pixel circuit in this display panel uses a common P-contact process, meaning that all switching transistors in the sub-pixel circuit are PMOS switching transistors. Figure 15 As shown, the display panel includes a sub-pixel circuit, a light-emitting device electrically connected to the sub-pixel circuit, a scan signal output module, a reference current module, and a control module. The sub-pixel circuit of the display panel includes: a first PMOS transistor, a second PMOS transistor, a third PMOS transistor, a fourth PMOS transistor, a fifth PMOS transistor, a sixth PMOS transistor, a seventh PMOS transistor, a capacitor, a first resistor, a second resistor, and an enable signal output unit.
[0121] in, Figure 15 The first to seventh PMOS transistors are the same as those mentioned above. Figure 14 The first through seventh NMOS transistors in the module function similarly, differing only in the type of MOS transistor. The remaining modules and devices offer similar technical advantages. Figure 14 The display panel in the embodiment is similar, the only difference being that Figure 15 sub-pixel circuit and Figure 14 The sub-pixel circuits in the embodiments are mirror images of each other, and will not be described again here.
[0122] Optionally, the sub-pixel circuits included in the display panel provided in this application can all be similar to those described above. Figure 14 The sub-pixel circuits employ a common N-contact process, or all of them can be similar to those described above. Figure 15 The sub-pixel circuits in the display panel can be made using a common P-contact process, or the display panel can simultaneously include sub-pixel circuits using both a common N-contact process and a common P-contact process.
[0123] On the other hand, this application also provides an electronic device, which includes the display panel shown in any of the foregoing embodiments. The technical effects of the electronic device are similar to those of the foregoing display panel, and will not be described again here.
[0124] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.
[0125] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.
Claims
1. A display panel, characterized in that, The display panel includes multiple pixels arranged in rows and columns, a control module, and a pulse width modulation (PWM) module. Each pixel includes multiple sub-pixel circuits and light-emitting devices electrically connected to each of the sub-pixel circuits. The control module is used to output a reset control signal to the sub-pixel circuit at the end of the display cycle of the display panel, so as to control the light-emitting device in the sub-pixel circuit to reset quickly and achieve rapid shutdown. The PWM module is connected to the control module and the light-emitting device respectively, and can generate PWM signals based on the control commands of the control module to adjust the brightness of the light-emitting device and realize the periodic display of the display panel.
2. The display panel according to claim 1, characterized in that, The control module is used to control the reset control signal to maintain a first level according to the scanning signal of the display panel through timing coordination, so as to control the sub-pixel circuit to reset the light-emitting device before the start of the display cycle and at the end of the display cycle.
3. The display panel according to claim 2, characterized in that, The reset control signal is a global reset control signal, and all sub-pixel circuits in the display panel are in a unified shutdown mode.
4. The display panel according to claim 3, characterized in that, The control terminal of the PWM module is connected to the second output terminal of the control module, the first terminal is connected to the anode of the light-emitting device, and the second terminal is connected to the power supply terminal of the light-emitting device.
5. The display panel according to claim 4, characterized in that, The sub-pixel circuit includes: a reset module; The input terminal of the reset module is connected to the first output terminal of the control module, and the output terminal is connected to the anode of the light-emitting device. The reset module is used to output a reset signal to the light-emitting device according to the reset control signal output by the control module. The reset signal is used to reset the light-emitting device and realize the rapid shutdown of the light-emitting device.
6. The display panel according to any one of claims 1-5, characterized in that, The control module is also used to switch the maintained first level to the second level before the start of the display cycle, and at the same time, the reset signal is switched from low voltage to high voltage, and then switched from high voltage to low voltage before the end of the display cycle, so as to reduce the voltage difference across the light-emitting device and improve the lighting speed of the light-emitting device.
7. The display panel according to claim 6, characterized in that, The reset signal maintains the high voltage until after the lowest grayscale pulse in the display panel begins and before the display cycle ends.
8. The display panel according to claim 7, characterized in that, The display panel also includes a scanning signal output module; the sub-pixel circuit also includes: a current mirror module and a pre-charge module; The output terminal of the current mirror module is connected to the second terminal of the PWM module, and the first input terminal is connected to the output terminal of the scan signal output module; the output terminal of the pre-charge module is connected to the second input terminal of the current mirror module, and the input terminal is connected to the control module. The pre-charging module is used to pre-charge the current mirror module before the scanning signal output module scans, so as to improve the charging speed of the current mirror module.
9. The display panel according to claim 8, characterized in that, The sub-pixel circuit also includes an overvoltage protection module; The overvoltage protection module is used to keep the voltage change in the sub-pixel circuit within the rated voltage range, thereby protecting the sub-pixel circuit.
10. The display panel according to claim 9, characterized in that, The control module is also used to acquire the light emission time of the light-emitting device and send the light emission time to the PWM module; Alternatively, the emission time can be obtained from the PWM module.
11. The display panel according to claim 10, characterized in that, The reset module includes a first switch and a reset power supply submodule; The first end of the first switch is connected to the output end of the control module, the second end is connected to the anode of the light-emitting device, and the third end is connected to the output end of the reset power supply submodule; The reset power supply submodule is used to output the reset signal; The first switch is configured to connect the path between the reset power supply submodule and the light-emitting device when the reset control signal changes from the second level to the first level, and to disconnect the path between the reset power supply submodule and the light-emitting device when the reset control signal changes from the first level to the second level.
12. The display panel according to claim 11, characterized in that, The first switch is an N-type metal-oxide-semiconductor switch, or a P-type metal-oxide-semiconductor switch, or a complementary metal-oxide-semiconductor switch.
13. The display panel according to claim 12, characterized in that, The display panel also includes: a reference current module; The current mirror module is connected to the reference current module and the light-emitting device respectively, and provides a driving current that can drive the light-emitting device to emit light based on the reference current signal provided by the reference current module.
14. The display panel according to claim 8, characterized in that, The pre-charging module includes: a second switch and a pre-charging power supply sub-module; The first input terminal of the second switch is connected to the output terminal of the pre-charge power supply submodule, and the second input terminal is connected to the output terminal of the control module; The pre-charge power module is used to output the pre-charge voltage; The second switch is used to open the path between the pre-charge power supply submodule and the current mirror module when a pre-charge indication signal is received from the control module.
15. The display panel according to claim 14, characterized in that, The second switch is an N-type metal-oxide-semiconductor switch, or a P-type metal-oxide-semiconductor switch, or a complementary metal-oxide-semiconductor switch.
16. The display panel according to claim 13, characterized in that, The overvoltage protection module includes: a first overvoltage protection module, and / or a second overvoltage protection module; The first terminal of the first overvoltage protection module is connected to the first terminal of the PWM module, and the second terminal is connected to the anode of the light-emitting device; The first end of the second overvoltage protection module is connected to the output end of the reference current module, and the second end is connected to the second input end of the current mirror module.
17. The display panel according to any one of claims 7-16, characterized in that, The sub-pixel circuit adopts a common N-contact process and / or a common P-contact process; the first sub-pixel circuit using the common N-contact process and the second sub-pixel circuit using the common P-contact process are mirror images of each other.
18. An electronic device, characterized in that, The electronic device includes a display panel as claimed in any one of claims 1-17.