Pixel circuit, display panel and display device

Abstract

The invention provides a pixel circuit, a display panel and a display device. 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, a second end of the driving module is connected with the 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 self control end in a light-emitting stage; a parasitic capacitor is arranged between the first power line and the second end of the driving module and used for coupling the voltage of the second end of the driving module in the light emitting stage so as to compensate the gray-scale voltage. According to the pixel circuit provided by the invention, the parasitic capacitor between the first power line and the second end of the driving module is coupled with the voltage of the second end of the driving module in the light emitting stage so as to compensate the gray-scale voltage, so that the gray-scale voltage under low brightness and low gray scale can be improved, the gray-scale voltage expansion precision under low brightness and low gray scale is improved, and the display effect of the pixel circuit is improved. The product display effect can be effectively improved.

Description

Technical Field

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

[0002] Organic Light Emitting Diode (OLED) and flat panel display devices based on technologies such as Light Emitting Diode (LED) have been widely used in various consumer electronic products such as mobile phones, televisions, laptops, desktop computers, etc. due to their advantages such as high image quality, power saving, thin body and wide application range, becoming the mainstream in display devices.

[0003] However, the performance of current OLED display products needs to be improved. Summary of the invention

[0004] In view of this, the purpose of the present application is to propose a pixel circuit, a display panel, and a display device, which can improve the grayscale voltage expansion accuracy under low brightness and low grayscale, thereby improving the product display effect.

[0005] Based on the above purpose, the present application provides a pixel circuit, which includes:

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

[0007] The first end of the driving module is connected to the first power line, the second end of the driving module is used to connect to the light-emitting module, and the driving module is used to control the light-emitting module to emit light according to the control signal of its control end during the light-emitting stage;

[0008] A parasitic capacitor is provided between the first power line and the second end of the driving module, and the parasitic capacitor is used to couple the voltage of the second end of the driving module in the light-emitting stage to compensate for the grayscale voltage; the parasitic capacitor is greater than or equal to 10F.

[0009] In one embodiment, the pixel circuit includes 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 in the second conductor layer, the second end of the driving module is located in 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 implementation manner, the pixel circuit further includes:

[0011] A data writing module, wherein the control end of the data writing module is connected to the first scanning signal line, the first end of the data writing module is connected to the data line, the second end of the data writing module is connected to the first end of the driving module, and the data writing module is used to respond to the signal on the first scanning signal line and write a voltage related to the data voltage on the data line to the control end of the driving module during the data writing stage.

[0012] In one implementation manner, the pixel circuit further includes:

[0013] a first reset module, wherein a control end of the first reset module is connected to the second scanning signal line, a first end of the first reset module is connected to the control end of the driving module, a second end of the first reset module is connected to the first reference signal line, and the first reset module is used to reset the control end of the driving module;

[0014] Preferably, the pixel circuit further includes:

[0015] a second reset module, wherein a control end of the second reset module is connected to the third scan signal line, a first end of the second reset module is connected to the anode of the light emitting module, a second end of the second reset module is connected to the second reference signal line, and the second reset module is used to reset the anode of the light emitting module;

[0016] Preferably, the pixel circuit further includes:

[0017] A third reset module, wherein the control end of the third reset module is connected to the third scanning signal line, the first end of the third reset module is connected to the first end of the driving module, the second end of the third reset module is connected to the third reference signal line, and the third reset module is used to reset the first end of the driving module.

[0018] In one implementation manner, the pixel circuit further includes:

[0019] a storage module, the storage module being connected to the control end of the driving module and being used to store the voltage of the control end of the driving module;

[0020] In one embodiment, the storage module includes 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.

[0021] In one implementation manner, the pixel circuit further includes:

[0022] A first light-emitting control module, wherein the control end of the first light-emitting control module is connected to a light-emitting control signal line, the first end of the first light-emitting control module is connected to the second end of the driving module, the 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 used to respond to the signal on the light-emitting control signal line to be turned on during the light-emitting stage.

[0023] In one implementation manner, the pixel circuit further includes:

[0024] A second light-emitting control module, wherein the first end of the second light-emitting control module is connected to the first end of the driving module, the control end of the second light-emitting control module is connected to a light-emitting control signal line, the second end of the second light-emitting control module is connected to the first power line, and the second light-emitting control module is used to respond to a signal on the light-emitting control signal line to turn on during the light-emitting stage.

[0025] In one implementation manner, the pixel circuit further includes:

[0026] A compensation module, wherein the control end of the compensation module is connected to the fourth scan signal line, the first end of the compensation module is connected to the control end of the driving module, the second end of the compensation module is connected to the second end of the driving module, and the compensation module is used to compensate for the threshold voltage of the driving module.

[0027] Based on the same inventive concept, the present application also discloses a display panel, which includes the pixel circuit as described above.

[0028] Based on the same inventive concept, the present application also discloses a display device, which includes the display panel as described above.

[0029] Compared with the prior art, the pixel circuit provided in the present application utilizes the parasitic capacitance between the first power line and the second end of the driving module to couple the voltage of the second end of the driving module during the light-emitting stage to compensate for the grayscale voltage, which is beneficial to improving the grayscale voltage under low brightness and low grayscale, thereby improving the grayscale voltage expansion accuracy under low brightness and low grayscale, and can effectively improve the product display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A schematic diagram of a pixel circuit provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of the layer structure of a pixel circuit provided in an embodiment of the present application;

[0033] Figure 3 A schematic diagram of a pixel circuit provided by another embodiment of the present application;

[0034] Figure 4 A schematic diagram of a pixel circuit provided by another embodiment of the present application;

[0035] Figure 5 A schematic diagram of a pixel circuit provided by another embodiment of the present application;

[0036] Figure 6 A schematic diagram of a pixel circuit provided by another embodiment of the present application;

[0037] Figure 7 A schematic diagram of a pixel circuit provided by another embodiment of the present application;

[0038] Figure 8 A schematic diagram of a pixel circuit provided according to another embodiment of the present application.

[0039] Marking Description:

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

[0041] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0042] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0043] In digital display systems, images are composed of many pixels, and each pixel can present different brightness levels to form a rich image effect. These different brightness levels are represented by grayscale. Grayscale usually ranges from 0 (darkest, usually representing black) to maximum (brightest, usually representing white). For example, for an 8-bit grayscale image, there may be 256 grayscales (0-255). Grayscale voltage is the specific voltage value corresponding to these different grayscales. By applying a specific grayscale voltage to the pixel circuit, the luminous brightness of the pixel is controlled, thereby achieving different grayscale displays.

[0044] Currently, for AMOLED (Active Matrix Organic Light Emitting Diode) products, the image quality at low brightness and low grayscale has always been the goal pursued by customers, and the image quality of current products at low brightness and low grayscale needs to be improved. After long-term research, the inventor found that the larger the grayscale voltage, the higher the grayscale voltage development accuracy, the better the image quality of the product at low brightness and low grayscale, and vice versa; however, the current itself is relatively small at low brightness, which puts more requirements on the grayscale voltage development accuracy.

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

[0046] Reference Figure 1 As shown, an embodiment of the present application discloses a pixel circuit 100, which includes a driving module and a first power line ELVDD; the first end of the driving module is connected to the first power line ELVDD, and the second end of the driving module is used to connect to the light-emitting module, and the driving module is used to control the light-emitting module to emit light according to the control signal of its own control end during the light-emitting stage.

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

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

[0049] Furthermore, the driving module includes a transistor, and the light emitting module includes 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 present application utilizes the parasitic capacitance between the first power line ELVDD and the second end of the driving module to couple the voltage of the second end of the driving module during the light-emitting stage to compensate for the grayscale voltage, which is beneficial to improving the grayscale voltage under low brightness and low grayscale, thereby improving the grayscale voltage expansion accuracy under low brightness and low grayscale, and can effectively improve the product display effect.

[0051] Among them, the parasitic capacitance is greater than or equal to 10F, such as 10F, 15F, 20F, 50F, 100F, etc., and there is no specific limitation. When the parasitic capacitance is greater than or equal to 10F, the grayscale voltage under low brightness and low grayscale can be significantly improved. It should be noted that when the parasitic capacitance is less than 10F, it can also improve the grayscale voltage under low brightness and low grayscale, but the larger the parasitic capacitance, the larger the grayscale voltage under low brightness and low grayscale, the higher the grayscale voltage expansion accuracy under low brightness and low grayscale, and the better the product display effect.

[0052] Reference Figure 2 As shown, 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 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 positive projection of the first power line ELVDD on the first conductor layer M1 at least partially covers the second end 10 of the driving module. Among them, the parasitic capacitance can be increased by the projection coverage. In theory, when other conditions remain unchanged, the larger the area covered by the projection, the larger the parasitic capacitance, so the parasitic capacitance can be adjusted by adjusting the area covered by the projection. In another embodiment, the parasitic capacitance can also be adjusted by adjusting the distance between the first power line ELVDD and the second end 10 of the driving module. In theory, when other conditions remain unchanged, the smaller the distance between the first power line ELVDD and the second end 10 of the driving module, the larger the parasitic capacitance. In addition, the parasitic capacitance can also be adjusted to the target value by changing the material, etc., which is not specifically limited.

[0053] Please continue to refer to Figure 2 As shown, 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, thereby adjusting the parasitic capacitance. In addition, the parasitic capacitance can also be adjusted by changing the material of the insulating layer 20, etc.

[0054] Reference Figure 3As shown, in one embodiment, the pixel circuit 100 also includes a data writing module, the control end of the data writing module is connected to the first scanning signal line SP1, the first end of the data writing module is connected to the data line Vdata, and the second end of the data writing module is connected to the first end of the driving module. The data writing module is used to respond to the signal on the first scanning signal line SP1, and write a voltage related to the data voltage on the data line Vdata to the control end of the driving module in the data writing stage, so that the driving module can generate a driving current according to the data voltage in the light-emitting stage to drive the light-emitting module to emit light.

[0055] Reference Figure 4 As shown, in one embodiment, the pixel circuit also includes a first reset module, the control end of the first reset module is connected to the second scanning signal line SN1, the first end of the first reset module is connected to the control end of the driving module, and the 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 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 also includes a second reset module, the control end of the second reset module is connected to the third scanning signal line SP2, the first end of the second reset module is connected to the anode of the light-emitting module, and the 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 to enhance 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 also includes a third reset module, the control end of the third reset module is connected to the third scanning signal line SP2, the first end of the third reset module is connected to the first end of the driving module, the second end of the third reset module is connected to the third reference signal line Vrefn, and the third reset module is used to reset the first end of the driving module.

[0058] Among them, the light-emitting module needs to go through at least three reset processes before emitting light, which further deteriorates the image quality at low brightness and low grayscale. Therefore, it is particularly important to use parasitic capacitance to couple the voltage of the second end of the driving module during the light-emitting stage to compensate for the grayscale voltage.

[0059] Reference Figure 5 As shown, in one embodiment, the pixel circuit 100 also includes a storage module, which 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 includes 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] Reference Figure 6As shown, in one embodiment, the pixel circuit 100 also includes a first light-emitting control module, the control end of the first light-emitting control module is connected to the light-emitting control signal line EM, the first end of the first light-emitting control module is connected to the second end of the driving module, the 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 used to respond to the signal on the light-emitting control signal line EM to be turned on in the light-emitting stage and turned off in the aging stage.

[0061] Please continue to refer to Figure 6 As shown, in one embodiment, the pixel circuit 100 also includes 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 line ELVDD, and the second light-emitting control module is used to respond to the signal on the light-emitting control signal line EM and be turned on during the light-emitting stage, so as to avoid the light-emitting module from emitting light during the data writing stage.

[0062] Please refer to Figure 7 As shown, in one embodiment, the pixel circuit 100 further includes a compensation module, the control end of the compensation module is connected to the fourth scanning signal line SN2, the first end of the compensation module is connected to the control end of the driving module, the second end of the compensation module is connected to the second end of the driving module, and the compensation module is used to compensate for the threshold voltage of the driving module. Preferably, the compensation module is a dual-gate threshold compensation transistor. Compared with a single-gate transistor, a dual-gate transistor has a lower leakage current, which is beneficial to reducing the potential fluctuation of the gate of the driving module.

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

[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, which includes the pixel circuit 100 in the above embodiment.

[0066] The display panel provided in this embodiment, whose pixel circuit 100 utilizes the parasitic capacitance between the first power line ELVDD and the second end of the driving module to couple the voltage of the second end of the driving module during the light-emitting stage to compensate for the grayscale voltage, which is beneficial to improving the grayscale voltage under low brightness and low grayscale, thereby improving the grayscale voltage expansion accuracy under low brightness and low grayscale, and is beneficial to improving the display performance of the display panel.

[0067] Another embodiment of the present embodiment discloses a display device, which includes the display panel in the above embodiment. The display device can be mounted on a smart device (such as a mobile phone, VR device, computer, TV, car display, etc.).

[0068] The display device provided in this embodiment, the pixel circuit 100 in the display panel thereof, utilizes the parasitic capacitance between the first power line ELVDD and the second end of the driving module to couple the voltage of the second end of the driving module during the light-emitting stage to compensate for the grayscale voltage, which is beneficial to improving the grayscale voltage under low brightness and low grayscale, thereby improving the grayscale voltage expansion accuracy under low brightness and low grayscale, and is beneficial to improving the display performance of the display device.

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

[0070] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0071] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A pixel circuit, characterized in that: include: A driving module and a first power line; The first end of the driving module is connected to the first power line, the second end of the driving module is used to connect to the light-emitting module, and the driving module is used to control the light-emitting module to emit light according to the control signal of its control end in the light-emitting stage; A parasitic capacitor is provided between the first power line and the second end of the driving module, and the parasitic capacitor is used to couple the voltage of the second end of the driving module in the light-emitting stage to compensate for the grayscale voltage; The parasitic capacitance is greater than or equal to 10F.

2. The pixel circuit according to claim 1, wherein: The pixel circuit includes 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.

3. The pixel circuit according to claim 1, wherein: The pixel circuit further comprises: A data writing module, wherein the control end of the data writing module is connected to the first scanning signal line, the first end of the data writing module is connected to the data line, the second end of the data writing module is connected to the first end of the driving module, and the data writing module is used to respond to the signal on the first scanning signal line and write a voltage related to the data voltage on the data line to the control end of the driving module during the data writing stage.

4. The pixel circuit according to claim 1, wherein: The pixel circuit further comprises: a first reset module, wherein a control end of the first reset module is connected to the second scanning signal line, a first end of the first reset module is connected to the control end of the driving module, a second end of the first reset module is connected to the first reference signal line, and the first reset module is used to reset the control end of the driving module; Preferably, the pixel circuit further includes: a second reset module, wherein a control end of the second reset module is connected to the third scan signal line, a first end of the second reset module is connected to the anode of the light emitting module, a second end of the second reset module is connected to the second reference signal line, and the second reset module is used to reset the anode of the light emitting module; Preferably, the pixel circuit further includes: A third reset module, wherein the control end of the third reset module is connected to the third scanning signal line, the first end of the third reset module is connected to the first end of the driving module, the second end of the third reset module is connected to the third reference signal line, and the third reset module is used to reset the first end of the driving module.

5. The pixel circuit according to claim 1, wherein: The pixel circuit further comprises: a storage module, the storage module being connected to the control end of the driving module and being used to store the voltage of the control end of the driving module; Preferably, 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.

6. The pixel circuit according to claim 1, wherein: The pixel circuit further comprises: A first light-emitting control module, wherein the control end of the first light-emitting control module is connected to a light-emitting control signal line, the first end of the first light-emitting control module is connected to the second end of the driving module, the 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 used to respond to the signal on the light-emitting control signal line to be turned on during the light-emitting stage.

7. The pixel circuit according to claim 1, wherein: The pixel circuit further comprises: A second light-emitting control module, wherein the first end of the second light-emitting control module is connected to the first end of the driving module, the control end of the second light-emitting control module is connected to a light-emitting control signal line, the second end of the second light-emitting control module is connected to the first power line, and the second light-emitting control module is used to respond to a signal on the light-emitting control signal line to turn on during the light-emitting stage.

8. The pixel circuit according to claim 1, wherein: The pixel circuit further comprises: A compensation module, wherein the control end of the compensation module is connected to the fourth scan signal line, the first end of the compensation module is connected to the control end of the driving module, the second end of the compensation module is connected to the second end of the driving module, and the compensation module is used to compensate for the threshold voltage of the driving module.

9. A display panel, characterized in that: Comprising the pixel circuit as described in any one of claims 1-8.

10. A display device, characterized in that: Comprising the display panel as claimed in claim 9.

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