Pixel circuit, display panel and display device

Abstract

The application provides a pixel circuit, a display panel and a display device. The pixel circuit comprises a driving module and a first power supply line. The first end of the driving module is connected with the first power supply line, and the second end of the driving module is used for being connected with a light-emitting module. The driving module is used for controlling the light-emitting module to emit light according to a control signal of a control end in a light-emitting stage. There is a parasitic capacitor between the first power supply line and the second end of the driving module. The parasitic capacitor is used for coupling the voltage of the second end of the driving module in the light-emitting stage to compensate for a gray scale voltage. The pixel circuit provided by the application couples the voltage of the second end of the driving module by using the parasitic capacitor between the first power supply line and the second end of the driving module in the light-emitting stage to compensate for the gray scale voltage. This is beneficial to improving the gray scale voltage under low brightness and low gray scale, thereby improving the gray scale voltage expansion precision under low brightness and low gray scale, and effectively improving the display effect of the product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a pixel circuit, a display panel and a display device. BACKGROUND

[0002] Organic light emitting diode (OLED) and flat display devices based on light emitting diode (LED) technology have been widely used in mobile phones, televisions, notebook computers, desktop computers and other consumer electronic products due to their high image quality, power saving, thin body and wide application range, and have become the mainstream of display devices.

[0003] However, the use performance of the current OLED display product needs to be improved. SUMMARY

[0004] Therefore, the present application aims to provide a pixel circuit, a display panel and a display device, which can improve the gray scale voltage expansion precision at low brightness and low gray scale, thereby improving the display effect of the product.

[0005] To achieve the above purpose, the present application provides a pixel circuit, which comprises:

[0006] a driving module and a first power line;

[0007] The first end of the driving module is connected with the first power line, the second end of the driving module is used to be connected with a light emitting module, and the driving module is used to control the light emitting module to emit light according to the control signal of the control end in the light emitting stage.

[0008] The first power line and the second end of the driving module have a parasitic capacitor, which is used to couple the voltage of the second end of the driving module in the light emitting stage to compensate the gray scale voltage; the parasitic capacitor is greater than or equal to 10F.

[0009] In one embodiment, the pixel circuit comprises a first conductor layer and a second conductor layer, the second conductor layer is located on one side of the first conductor layer, the first power line is located on the second conductor layer, the second end of the driving module is located on the first conductor layer, and the orthographic projection of the first power line on the first conductor layer at least partially covers the second end of the driving module.

[0010] In one embodiment, the pixel circuit further comprises:

[0011] a data writing module, a control terminal of the data writing module is connected with the first scan signal line, a first terminal of the data writing module is connected with the data line, and a second terminal of the data writing module is connected with the first terminal of the driving module, and the data writing module is configured to write a voltage related to a data voltage on the data line to the control terminal of the driving module in a data writing stage in response to a signal on the first scan signal line.

[0012] In one embodiment, the pixel circuit further comprises:

[0013] a first reset module, a control terminal of the first reset module is connected with the second scan signal line, a first terminal of the first reset module is connected with the control terminal of the driving module, and a second terminal of the first reset module is connected with the first reference signal line, and the first reset module is configured to reset the control terminal of the driving module.

[0014] Preferably, the pixel circuit further comprises:

[0015] a second reset module, a control terminal of the second reset module is connected with the third scan signal line, a first terminal of the second reset module is connected with the anode of the light emitting module, and a second terminal of the second reset module is connected with the second reference signal line, and the second reset module is configured to reset the anode of the light emitting module.

[0016] Preferably, the pixel circuit further comprises:

[0017] a third reset module, a control terminal of the third reset module is connected with the third scan signal line, a first terminal of the third reset module is connected with the first terminal of the driving module, and a second terminal of the third reset module is connected with the third reference signal line, and the third reset module is configured to reset the first terminal of the driving module.

[0018] In one embodiment, the pixel circuit further comprises:

[0019] a storage module, the storage module is connected with the control terminal of the driving module, and is configured to store a voltage of the control terminal of the driving module.

[0020] In one embodiment, the storage module comprises a storage capacitor, a first terminal of the storage capacitor is connected with the control terminal of the driving module, and a second terminal of the storage capacitor is connected with the first terminal of the driving module.

[0021] In one embodiment, the pixel circuit further comprises:

[0022] A first light emitting control module, a control end of the first light emitting control module is connected with a light emitting control signal line, a first end of the first light emitting control module is connected with a second end of the driving module, a second end of the first light emitting control module is connected with an anode of the light emitting module, and the first light emitting control module is used for turning on in the light emitting stage in response to a signal on the light emitting control signal line.

[0023] In one of the embodiments, the pixel circuit further comprises:

[0024] A second light emitting control module, a first end of the second light emitting control module is connected with a first end of the driving module, a control end of the second light emitting control module is connected with the light emitting control signal line, a second end of the second light emitting control module is connected with the first power supply line, and the second light emitting control module is used for turning on in the light emitting stage in response to the signal on the light emitting control signal line.

[0025] In one of the embodiments, the pixel circuit further comprises:

[0026] A compensation module, a control end of the compensation module is connected with a fourth scanning signal line, a first end of the compensation module is connected with a control end of the driving module, a second end of the compensation module is connected with a second end of the driving module, and the compensation module is used for compensating a threshold voltage of the driving module.

[0027] Based on the same inventive concept, the application further discloses a display panel, which comprises the pixel circuit.

[0028] Based on the same inventive concept, the application further discloses a display device, which comprises the display panel.

[0029] Compared with the prior art, the pixel circuit provided by the application utilizes the parasitic capacitance between the first power supply line and the second end of the driving module to couple the voltage of the second end of the driving module in the light emitting stage, so as to compensate the gray scale voltage, which is beneficial to improve the gray scale voltage under low brightness and low gray scale, thereby improving the gray scale voltage expansion precision under low brightness and low gray scale, and can effectively improve the display effect of the product. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the application or the related art, the following will briefly introduce the drawings needed to be used in the embodiments or the related art description. Obviously, the drawings in the following description are only embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0031] Figure 1 The schematic diagram of the pixel circuit provided by an embodiment of the application;

[0032] Figure 2 A schematic diagram of a layer structure of a pixel circuit provided by an embodiment of the present application is shown in FIG. 1.

[0033] Figure 3 A schematic diagram of a pixel circuit provided by another embodiment of the present application is shown in FIG. 2.

[0034] Figure 4 A schematic diagram of a pixel circuit provided by another embodiment of the present application is shown in FIG. 3.

[0035] Figure 5 A schematic diagram of a pixel circuit provided by another embodiment of the present application is shown in FIG. 4.

[0036] Figure 6 A schematic diagram of a pixel circuit provided by another embodiment of the present application is shown in FIG. 5.

[0037] Figure 7 A schematic diagram of a pixel circuit provided by another embodiment of the present application is shown in FIG. 6.

[0038] Figure 8 A schematic diagram of a pixel circuit provided by another embodiment of the present application is shown in FIG. 7.

[0039] Legend:

[0040] 100, pixel circuit; 10, second end of a driving module; 20, insulating layer. DETAILED DESCRIPTION

[0041] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0042] It should be noted that, unless otherwise defined, technical terms or scientific terms used in the embodiments of the present application should be understood as their common meanings to those of ordinary skill in the art to which the present application pertains. The terms "first", "second" and similar terms used in the embodiments of the present application do not denote any order, quantity or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, without excluding other elements or objects. The terms "connect" or "connected" and similar terms do not mean only physical or mechanical connections, but can also include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right" and the like only represent relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships can also be changed accordingly.

[0043] In a digital display system, an image is composed of many pixels, each of which can present different brightness levels to form a rich image effect. These different brightness levels are represented by gray scales. Gray scales usually range from 0 (darkest, usually representing black) to a maximum value (brightest, usually representing white). For example, for an 8-bit gray scale image, there can be 256 gray scales (0-255). Gray scale voltage is the specific voltage value corresponding to these different gray scales. By applying a specific gray scale voltage to the pixel circuit, the luminance of the pixel is controlled, thereby achieving different gray scale displays.

[0044] Currently, for AMOLED (Active Matrix Organic Light Emitting Diode) products, the image quality at low brightness and low gray scale has always been the goal pursued by customers, and the image quality at low brightness and low gray scale of current products needs to be improved. The inventors have found through long-term research that the greater the gray scale voltage, the higher the gray scale voltage expansion precision, and the better the image quality of the product at low brightness and low gray scale, and vice versa. However, the current at low brightness is relatively small, which puts more requirements on the gray scale voltage expansion precision.

[0045] Based on this, the present application provides a pixel circuit scheme to solve the above problems, with reference to the following embodiments.

[0046] Referring to Figure 1 An embodiment of the present application discloses a pixel circuit 100, which comprises a driving module and a first power line ELVDD; a first end of the driving module is connected with the first power line ELVDD, a second end of the driving module is used for connecting with a light emitting module, and the driving module is used for controlling the light emitting module to emit light according to a control signal of a control end of the driving module in a light emitting stage.

[0047] A parasitic capacitor is arranged between the first power line ELVDD and the second end of the driving module, and the parasitic capacitor is used for coupling the voltage of the second end of the driving module in the light emitting stage to compensate the gray scale voltage.

[0048] The second end of the light emitting module is connected with a second power line ELVSS, the second power line RLVSS is connected with a second power voltage, the first power voltage is a positive voltage, and the second power voltage is a negative voltage.

[0049] Further, the driving module comprises a transistor, and the light emitting module comprises an OLED or an AMOLED, etc. The first end of the driving module is a source, the second end of the driving module is a drain, and the control end of the driving module is a gate.

[0050] The pixel circuit 100 provided in the application utilizes the parasitic capacitance between the first power supply line ELVDD and the second end of the driving module to couple the voltage of the second end of the driving module in the light-emitting stage to compensate the gray-scale voltage, which is conducive to improving the gray-scale voltage under low brightness and low gray scale, thereby improving the gray-scale voltage expansion precision under low brightness and low gray scale, and effectively improving the product display effect.

[0051] The parasitic capacitance is greater than or equal to 10F, for example, 10F, 15F, 20F, 50F, 100F, etc., and is not limited in particular. When the parasitic capacitance is greater than or equal to 10F, the gray-scale voltage under low brightness and low gray scale can be significantly improved. It should be noted that when the parasitic capacitance is less than 10F, it can also improve the gray-scale voltage under low brightness and low gray scale, but the greater the parasitic capacitance, the greater the gray-scale voltage under low brightness and low gray scale, the higher the gray-scale voltage expansion precision under low brightness and low gray scale, and the better the product display effect.

[0052] Referring to Figure 2 In one embodiment, the pixel circuit 100 includes a first conductor layer M1 and a second conductor layer M2, the second conductor layer M2 is located on one side of the first conductor layer M1, the first power supply line ELVDD is located on the second conductor layer M2, the second end 10 of the driving module is located on the first conductor layer M1, and the orthographic projection of the first power supply line ELVDD on the first conductor layer M1 at least partially covers the second end 10 of the driving module. The projection coverage can improve the parasitic capacitance. In theory, under the condition that other conditions remain unchanged, the larger the projection coverage area, the greater the parasitic capacitance, and therefore the parasitic capacitance can be adjusted by adjusting the projection coverage area. In another embodiment, the parasitic capacitance can also be adjusted by adjusting the distance between the first power supply line ELVDD and the second end 10 of the driving module. In theory, under the condition that other conditions remain unchanged, the smaller the distance between the first power supply line ELVDD and the second end 10 of the driving module, the greater the parasitic capacitance. In addition, the parasitic capacitance can also be adjusted to a target value by changing the material and other ways, which are not limited in particular.

[0053] Please refer to Figure 2 As shown in the figure, preferably, the pixel circuit 100 includes an insulating layer 20 located between the first conductor layer M1 and the second conductor layer M2, and the distance between the first conductor layer M1 and the second conductor layer M2 can be changed by changing the thickness of the insulating layer 20, so as to adjust the parasitic capacitance. In addition, the parasitic capacitance can also be adjusted by changing the material of the insulating layer 20.

[0054] Referring to Figure 3As shown, in one embodiment, the pixel circuit 100 further comprises a data writing module, a control end of the data writing module is connected to the first scan signal line SP1, a first end of the data writing module is connected to the data line Vdata, and a second end of the data writing module is connected to the first end of the driving module. The data writing module is used to write a voltage related to the data voltage on the data line Vdata to the control end of the driving module in a data writing stage in response to a signal on the first scan signal line SP1, so as to facilitate the driving module to generate a driving current according to the data voltage in a light emitting stage, so as to drive the light emitting module to emit light.

[0055] Referring to Figure 4 As shown, in one embodiment, the pixel circuit further comprises a first reset module, a control end of the first reset module is connected to the second scan signal line SN1, a first end of the first reset module is connected to the control end of the driving module, and a second end of the first reset module is connected to the first reference signal line Vref1. The first reset module is used to reset the control end of the driving module, so as to improve the driving effect of the driving module.

[0056] Please continue to refer to Figure 4 As shown, in one embodiment, the pixel circuit further comprises a second reset module, a control end of the second reset module is connected to the third scan signal line SP2, a first end of the second reset module is connected to the anode of the light emitting module, and a second end of the second reset module is connected to the second reference signal line Vref2. The second reset module is used to reset the anode of the light emitting module, so as to improve the light emitting effect of the light emitting module.

[0057] Please continue to refer to Figure 4 As shown, in one embodiment, the pixel circuit further comprises a third reset module, a control end of the third reset module is connected to the third scan signal line SP2, a first end of the third reset module is connected to the first end of the driving module, and a second end of the third reset module is connected to the third reference signal line Vrefn. The third reset module is used to reset the first end of the driving module.

[0058] The light emitting module needs to go through at least three reset processes before emitting light, which further deteriorates the picture quality at low brightness and low gray scale. Therefore, it is particularly important to use the parasitic capacitance to couple the voltage of the second end of the driving module in the light emitting stage to compensate the gray scale voltage.

[0059] Referring to Figure 5 As shown, in one embodiment, the pixel circuit 100 further comprises a storage module, the storage module is connected to the control end of the driving module and is used to store the voltage of the control end of the driving module. Further, the storage module comprises a storage capacitor, a first end of the storage capacitor is connected to the control end of the driving module, and a second end of the storage capacitor is connected to the first end of the driving module.

[0060] Referring to Figure 6As shown in the pixel circuit 100, in one embodiment, the pixel circuit 100 further comprises a first light-emitting control module, a control end of the first light-emitting control module is connected to the light-emitting control signal line EM, a first end of the first light-emitting control module is connected to the second end of the driving module, a second end of the first light-emitting control module is connected to the anode of the light-emitting module, and the first light-emitting control module is configured to be turned on in the light-emitting stage and turned off in the aging stage in response to a signal on the light-emitting control signal line EM.

[0061] Please continue to refer to Figure 6 As shown in the pixel circuit 100, in one embodiment, the pixel circuit 100 further comprises a second light-emitting control module, a first end of the second light-emitting control module is connected to the first end of the driving module, a control end of the second light-emitting control module is connected to the light-emitting control signal line EM, a second end of the second light-emitting control module is connected to the first power supply line ELVDD, and the second light-emitting control module is configured to be turned on in the light-emitting stage in response to a signal on the light-emitting control signal line EM, so as to avoid the light-emitting module from emitting light in the data writing stage.

[0062] Please refer to Figure 7 As shown in the pixel circuit 100, in one embodiment, the pixel circuit 100 further comprises a compensation module, a control end of the compensation module is connected to the fourth scan signal line SN2, a first end of the compensation module is connected to the control end of the driving module, and a second end of the compensation module is connected to the second end of the driving module, and the compensation module is configured to compensate the threshold voltage of the driving module. Preferably, the compensation module is a double-gate threshold compensation transistor, which has a lower leakage current than a single-gate transistor, and is conducive to reducing the potential fluctuation of the gate of the driving module.

[0063] In one embodiment, the pixel circuit 100 comprises an 8T1C circuit, and the connection relationship is shown in detail in Figure 8 . The driving module comprises a transistor T1, the light-emitting module comprises an AMOLED, the data writing module comprises a transistor T2, the compensation module comprises a transistor T3, the first reset module comprises a transistor T4, the first light-emitting control module comprises a transistor T6, the second light-emitting control module comprises a transistor T5, the second reset module comprises a transistor T7, the third reset module comprises a transistor T8, and the parasitic capacitance between the first power supply line ELVDD and the second end of the driving module is C1; wherein the transistor T3 and the transistor T4 are NMOS transistors, and the transistor T1, the transistor T2, the transistor T5, the transistor T6, the transistor T7, and the transistor T8 are PMOS transistors.

[0064] Before the AMOLED emits light, the reset process of the pixel circuit is as follows: first, the signal on the third reference signal line Vrefn resets the gate of the transistor T1 through the transistor T8, the transistor T1 and the transistor T3; then, the signal on the first reference signal line Vref1 resets the gate of the transistor T1 again through the transistor T4; then, the signal on the second reference signal line Vref2 resets the anode of the AMOLED through the transistor T7, and the signal on the third reference signal line Vrefn resets the source of the transistor T1 through the transistor T8.

[0065] Another embodiment of the present application discloses a display panel comprising the pixel circuit 100 in the above embodiments.

[0066] The display panel provided by the embodiment has the pixel circuit 100, which utilizes the parasitic capacitance between the first power supply line ELVDD and the second end of the driving module to couple the voltage of the second end of the driving module in the light-emitting stage, so as to compensate the gray scale voltage, thereby improving the gray scale voltage under low brightness and low gray scale, improving the gray scale voltage expansion precision under low brightness and low gray scale, and improving the display performance of the display panel.

[0067] Another embodiment of the present application discloses a display device comprising the display panel in the above embodiments. The display device can be mounted on a smart device (such as a mobile phone, a VR device, a computer, a television, a vehicle-mounted display, and the like).

[0068] The display device provided by the embodiment has the pixel circuit 100 in the display panel, which utilizes the parasitic capacitance between the first power supply line ELVDD and the second end of the driving module to couple the voltage of the second end of the driving module in the light-emitting stage, so as to compensate the gray scale voltage, thereby improving the gray scale voltage under low brightness and low gray scale, improving the gray scale voltage expansion precision under low brightness and low gray scale, and improving the display performance of the display device.

[0069] Although the present application has been described in conjunction with the specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description.

[0070] It should be noted that some embodiments of the present application have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order and still achieve desirable results. Additionally, the processes depicted in the figures do not necessarily require the particular order shown, or sequential order to achieve the desired results. In certain implementations, multitasking and parallel processing can be advantageous.

[0071] Embodiments of the present application are intended to embrace all such alterations, modifications, and variations that fall within the broad scope of the appended claims. Accordingly, any one or more features of a given embodiment are intended to be illustrative only and not limiting of the scope of the application.

Claims

1. A pixel circuit, characterized by comprising: The pixel circuit comprises: a driving module and a first power line; a first end of the driving module is connected with the first power line, and a second end of the driving module is used for being connected with a light-emitting module, and the driving module is used for controlling the light-emitting module to emit light according to a control signal of a control end of the driving module in a light-emitting stage; a parasitic capacitor is arranged between the first power line and the second end of the driving module, and the parasitic capacitor is used for coupling a voltage of the second end of the driving module to compensate for a gray-scale voltage in the light-emitting stage; the parasitic capacitor is greater than or equal to 10 F; the pixel circuit comprises a first conductor layer and a second conductor layer, the second conductor layer is located on one side of the first conductor layer, the first power line is located on the second conductor layer, the second end of the driving module is located on the first conductor layer, and a normal projection of the first power line on the first conductor layer at least partially covers the second end of the driving module.

2. The pixel circuit of claim 1, wherein, The pixel circuit further comprises: a data writing module, a control end of the data writing module is connected with a first scan signal line, a first end of the data writing module is connected with a data line, and a second end of the data writing module is connected with the first end of the driving module, and the data writing module is used for writing a voltage related to a data voltage on the data line to the control end of the driving module in a data writing stage in response to a signal on the first scan signal line.

3. The pixel circuit of claim 1, wherein, The pixel circuit further comprises: a first reset module, a control end of the first reset module is connected with a second scan signal line, a first end of the first reset module is connected with the control end of the driving module, and a second end of the first reset module is connected with a first reference signal line, and the first reset module is used for resetting the control end of the driving module.

4. The pixel circuit of claim 1, wherein, The pixel circuit further comprises: a second reset module, a control end of the second reset module is connected with a third scan signal line, a first end of the second reset module is connected with an anode of the light-emitting module, and a second end of the second reset module is connected with a second reference signal line, and the second reset module is used for resetting the anode of the light-emitting module.

5. The pixel circuit of claim 4, wherein, The pixel circuit further comprises: a third reset module, a control end of the third reset module is connected with the third scan signal line, a first end of the third reset module is connected with the first end of the driving module, and a second end of the third reset module is connected with a third reference signal line, and the third reset module is used for resetting the first end of the driving module.

6. The pixel circuit of claim 1, wherein, The pixel circuit further comprises: a storage module, the storage module is connected with the control end of the driving module and is used for storing a voltage of the control end of the driving module.

7. The pixel circuit of claim 6, wherein, The storage module comprises a storage capacitor, a first end of the storage capacitor is connected with the control end of the driving module, and a second end of the storage capacitor is connected with the first end of the driving module.

8. The pixel circuit of claim 1, wherein, The pixel circuit further comprises: A first light emitting control module, a control terminal of the first light emitting control module is connected with a light emitting control signal line, a first terminal of the first light emitting control module is connected with a second terminal of the driving module, a second terminal of the first light emitting control module is connected with an anode of the light emitting module, and the first light emitting control module is used for turning on in the light emitting stage in response to a signal on the light emitting control signal line.

9. The pixel circuit of claim 1, wherein, The pixel circuit further comprises: A second light emitting control module, a first terminal of the second light emitting control module is connected with a first terminal of the driving module, a control terminal of the second light emitting control module is connected with a light emitting control signal line, a second terminal of the second light emitting control module is connected with the first power supply line, and the second light emitting control module is used for turning on in the light emitting stage in response to a signal on the light emitting control signal line.

10. The pixel circuit of claim 1, wherein, The pixel circuit further comprises: A compensation module, a control terminal of the compensation module is connected with a fourth scanning signal line, a first terminal of the compensation module is connected with a control terminal of the driving module, a second terminal of the compensation module is connected with a second terminal of the driving module, and the compensation module is used for compensating a threshold voltage of the driving module.

11. A display panel, characterized by, The display panel comprises the pixel circuit according to any one of claims 1-10.

12. A display device, characterized by comprising: The display panel comprises the pixel circuit according to claim 11.

Images