Light-emitting circuit and display panel
By synchronously controlling the on and off of the switching unit in the light-emitting circuit, the problems of increased power consumption and reliability caused by changes in the current characteristics of the driving transistor are solved, achieving the effects of light-emitting stability and reduced power consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHENZHEN CHINA STAR OPTOELECTRONICS SEMICON DISPLAY TECH CO LTD
- Filing Date
- 2022-12-29
- Publication Date
- 2026-06-05
AI Technical Summary
In actively driven display panels, when the current characteristics of the driving transistor change or are damaged, current flows into the light-emitting element, increasing power consumption, causing insufficient writing and poor reliability.
A light-emitting circuit is adopted, including a first transistor, a second transistor, a light-emitting unit, a switching unit, a capacitor, and a current source. By synchronously controlling the switching unit to turn on and off, the direction of current flow is controlled to prevent current from flowing into the light-emitting unit during the writing stage, and to reduce the current flowing through the light-emitting unit during the light-emitting stage, thereby reducing the influence of the transistor's parasitic capacitance and wire resistance.
Reduce power consumption, improve luminous stability and reliability, and reduce the adverse effects of transistors without changing the power line potential.
Smart Images
Figure CN116189599B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of display technology, specifically to a light-emitting circuit and a display panel. Background Technology
[0002] The driving methods for the light-emitting elements of self-emissive display devices are divided into passive driving and active driving. The former has a simple structure and can effectively reduce manufacturing costs; however, its high driving voltage makes it unsuitable for large-size and high-resolution display panels, which deviates from current development trends. The latter uses independent transistors to control each pixel, and each pixel can be driven to emit light continuously and independently.
[0003] If the current characteristics of the driving transistor change or are damaged, current will flow into the light-emitting element during signal writing, leading to problems such as increased power consumption, insufficient writing, and poor reliability. Summary of the Invention
[0004] This application provides a light-emitting circuit and a display panel to alleviate the technical problem of current flowing into the light-emitting element during the writing process.
[0005] In a first aspect, this application provides a light-emitting circuit, which includes a first transistor, a second transistor, a light-emitting unit, a first switching unit, a first capacitor, a second switching unit, a current source, and a third switching unit. The first terminal of the first transistor is electrically connected to a first power line; the first terminal of the second transistor is electrically connected to the second terminal of the first transistor; the first terminal of the light-emitting unit is electrically connected to the second terminal of the second transistor, and the second terminal of the light-emitting unit is electrically connected to a second power line; the first terminal of the first switching unit is electrically connected to a charging terminal, and the second terminal of the first switching unit is electrically connected to the gate of the first transistor, the gate of the second transistor, and the second terminal of the second transistor; the first terminal of the first capacitor is electrically connected to the second terminal of the first switching unit; the first terminal of the second switching unit is electrically connected to the second terminal of the first capacitor; the first terminal of the current source is electrically connected to the second terminal of the second switching unit, and the second terminal of the current source is electrically connected to a third power line; the first terminal of the third switching unit is electrically connected to the first terminal of the first transistor, and the second terminal of the third switching unit is electrically connected to the second terminal of the first transistor; wherein the first switching unit, the second switching unit, and the third switching unit are synchronously turned on or synchronously turned off.
[0006] In some embodiments, during the writing phase, the first switching unit, the second switching unit, and the third switching unit are simultaneously turned on to control the current flowing through the first switching unit through the first circuit.
[0007] The current flows from the capacitor, the second switching unit, and the current source to the third power line, and controls the current flowing through the third switching unit and the fifth transistor to flow through the first capacitor, the second switching unit, and the current source to the third power line.
[0008] In some embodiments, during the light-emitting phase, the first switching unit, the second switching unit, and the third switching unit are simultaneously turned off to control the current flowing through the first transistor and the second transistor to flow through the light-emitting unit to the second power line.
[0009] In some embodiments, the light-emitting circuit further includes a first compensation unit and a second compensation unit, wherein the first compensation unit is electrically connected to the gate of the first transistor to reduce the threshold voltage drift of the first transistor.
[0010] The second compensation unit is electrically connected to the gate of the second transistor to reduce the threshold voltage drift of the second transistor.
[0011] In some embodiments, the charging end is used to transmit data signals, and the light-emitting unit includes a light-emitting device, which is an organic light-emitting diode, a micro light-emitting diode, a mini light-emitting diode, or a quantum dot light-emitting diode.
[0012] 5. In some embodiments, the first power line is used to transmit a positive power signal, and the second power line is used for...
[0013] The first power supply negative signal is transmitted, and the third power supply line is used to transmit the second power supply negative signal. The potential of the second power supply negative signal is lower than that of the first power supply negative signal.
[0014] In some embodiments, the second power line and the third power line are the same power line.
[0015] In some embodiments, the light-emitting circuit further includes a switch control line, which is electrically connected to the control terminal of the first switch unit, the control terminal of the second switch unit, and the control terminal of the third switch unit.
[0016] In some embodiments, the first switching unit is a third transistor. The first terminal of the third transistor is electrically connected to the charging terminal, and the second terminal of the third transistor is electrically connected to the first terminal of the first capacitor, the second terminal of the second transistor, the gate of the first transistor, and the gate of the second transistor. The gate of the third transistor...
[0017] Electrically connected to the switch control line; the second switch unit is the fourth transistor, the first terminal of the fourth transistor is electrically connected to the second terminal of the fifth capacitor, and the second terminal of the fourth transistor is electrically connected to the first terminal of the current source.
[0018] The gate of the transistor is electrically connected to the switch control line; the third switching unit is the fifth transistor, the first terminal of the fifth transistor is electrically connected to the first terminal of the first transistor, the second terminal of the fifth transistor is electrically connected to the second terminal of the first transistor, and the gate of the fifth transistor is electrically connected to the switch control line.
[0019] Secondly, this application provides a display panel that includes a plurality of light-emitting circuits as described in at least one of the above embodiments.
[0020] The light-emitting circuit and display panel provided in this application, by simultaneously turning on the first switching unit, the second switching unit, and the third switching unit during the writing phase, can control the current flowing through the first switching unit to flow through the first capacitor, the second switching unit, and the current source to the third power line, and control the current flowing through the third switching unit and the second transistor to flow through the first capacitor, the second switching unit, and the current source to the third power line, thus avoiding the current flowing to the light-emitting unit during the writing phase. This can reduce power consumption without changing the potential transmitted by the first power line. By simultaneously turning off the first switching unit, the second switching unit, and the third switching unit during the light-emitting phase, the current flowing through the first transistor and the second transistor can be controlled to flow through the light-emitting unit to the second power line. Since the current passes through the two channels of the first transistor and the second transistor, the current flowing through the light-emitting unit is reduced, which can reduce the adverse effects of parasitic capacitance and wire resistance on these two transistors. Attached Figure Description
[0021] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.
[0022] Figure 1 This is a schematic diagram of the structure of the light-emitting circuit provided in an embodiment of this application.
[0023] Figure 2 This is a schematic diagram of the first current flow of the light-emitting circuit provided in the embodiments of this application.
[0024] Figure 3 This is a schematic diagram of a second current flow for the light-emitting circuit provided in an embodiment of this application. Detailed Implementation
[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Features thus defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more unless otherwise explicitly specified.
[0027] In view of the aforementioned technical problem that current flows into the light-emitting element during the writing process, this embodiment provides a light-emitting circuit. Please refer to [link to relevant documentation]. Figures 1 to 3 ,like Figure 1 As shown, the light-emitting circuit includes a first transistor T1, a second transistor T2, a light-emitting unit 40, a first switching unit 10, a first capacitor C1, a second switching unit 20, a current source 70, and a third switching unit 30. The first terminal of the first transistor T1 is electrically connected to the first power supply line; the first terminal of the second transistor T2 is electrically connected to the second terminal of the first transistor T1; the first terminal of the light-emitting unit 40 is electrically connected to the second terminal of the second transistor T2, and the second terminal of the light-emitting unit 40 is electrically connected to the second power supply line; the first terminal of the first switching unit 10 is electrically connected to the charging terminal, and the second terminal of the first switching unit 10 is connected to the gate of the first transistor T1 and the second transistor T2. The gate of T2 and the second terminal of the second transistor T2 are electrically connected; the first terminal of the first capacitor C1 is electrically connected to the second terminal of the first switching unit 10; the first terminal of the second switching unit 20 is electrically connected to the second terminal of the first capacitor C1; the first terminal of the current source 70 is electrically connected to the second terminal of the second switching unit 20, and the second terminal of the current source 70 is electrically connected to the third power line; the first terminal of the third switching unit 30 is electrically connected to the first terminal of the first transistor T1, and the second terminal of the third switching unit 30 is electrically connected to the second terminal of the first transistor T1; wherein, the first switching unit 10, the second switching unit 20 and the third switching unit 30 are synchronously turned on or synchronously turned off.
[0028] It is understood that the light-emitting circuit provided in this embodiment, by simultaneously turning on the first switching unit 10, the second switching unit 20, and the third switching unit 30 during the writing phase, can control the current flowing through the first switching unit 10 to flow through the first capacitor C1, the second switching unit 20, and the current source 70 to the third power line, and control the current flowing through the third switching unit 30 and the second transistor T2 to flow through the first capacitor C1, the second switching unit 20, and the current source 70 to the third power line, thus avoiding the current flowing to the light-emitting unit 40 during the writing phase. This can reduce power consumption without changing the potential transmitted by the first power line. By simultaneously turning off the first switching unit 10, the second switching unit 20, and the third switching unit 30 during the light-emitting phase, the current flowing through the first transistor T1 and the second transistor T2 can be controlled to flow through the light-emitting unit 40 to the second power line. Since the current passes through the two channels of the first transistor T1 and the second transistor T2, the current flowing through the light-emitting unit 40 is reduced, which can reduce the adverse effects of parasitic capacitance and wire resistance on these two transistors.
[0029] It should be noted that the first electrode can be either the source or the drain, and the second electrode can be either the source or the drain. For example, when the first electrode is the source, the second electrode is the drain; or, when the first electrode is the drain, the second electrode is the source.
[0030] The first transistor T1 is a low-leakage thin-film transistor, which can more accurately control the current flowing through the light-emitting unit 40, thereby enabling more stable control of the light-emitting unit 40's brightness. The second transistor T2 is a high-mobility thin-film transistor, which can control the current flowing through the third switching unit 30 and the second transistor T2 to flow more quickly to the first capacitor C1 during the writing stage.
[0031] Furthermore, the light-emitting circuit in this embodiment can be applied not only to pixel circuits and backlight driving circuits in the display field, but also to the lighting field.
[0032] In one embodiment, such as Figure 2 As shown, during the writing phase, the first switching unit 10, the second switching unit 20, and the third switching unit 30 of the light-emitting circuit are synchronously turned on to control the current flowing through the first switching unit 10 to flow through the first capacitor C1, the second switching unit 20, and the current source 70 to the third power line, and to control the current flowing through the third switching unit 30 and the second transistor T2 to flow through the first capacitor C1, the second switching unit 20, and the current source 70 to the third power line.
[0033] It should be noted that this avoids current flowing to the light-emitting unit 40 during the writing phase, which reduces power consumption without changing the potential transmitted by the first power line.
[0034] In one embodiment, such as Figure 3 As shown, during the light-emitting stage, the first switching unit 10, the second switching unit 20, and the third switching unit 30 are simultaneously turned off to control the current flowing through the first transistor T1 and the second transistor T2 to flow through the light-emitting unit 40 to the second power line.
[0035] It should be noted that since the current passes through the two channels of the first transistor T1 and the second transistor T2, the current flowing through the light-emitting unit 40 is reduced, which can reduce the adverse effects of parasitic capacitance and wire resistance on these two transistors.
[0036] In one embodiment, the light-emitting circuit further includes a first compensation unit 50 and a second compensation unit 60. The first compensation unit 50 is electrically connected to the gate of the first transistor T1 to reduce the threshold voltage drift of the first transistor T1; the second compensation unit 60 is electrically connected to the gate of the second transistor T2 to reduce the threshold voltage drift of the second transistor T2.
[0037] It should be noted that the first compensation unit 50 and the second compensation unit 60 can prevent the threshold voltage drift of the first transistor T1 and the second transistor T2, respectively, and can more accurately control the light-emitting unit 40 flowing through it to obtain ideal brightness.
[0038] In one embodiment, the charging end is used to transmit data signals, and the light-emitting unit 40 includes a light-emitting device, which is an organic light-emitting diode, a micro light-emitting diode, a mini light-emitting diode, or a quantum dot light-emitting diode.
[0039] It should be noted that when the aforementioned light-emitting circuit is used in the display field as a pixel circuit or backlight driving circuit, the charging end is connected to a data signal. However, in other application scenarios, the charging end can also be connected to other power signals, such as VDD1.
[0040] In one embodiment, a first power line is used to transmit a positive power signal VDD2, a second power line is used to transmit a first negative power signal VSS2, and a third power line is used to transmit a second negative power signal VSS1, wherein the potential of the second negative power signal VSS1 is lower than the potential of the first negative power signal VSS2.
[0041] It should be noted that in this embodiment, the potential of the second power supply negative signal VSS1 is configured to be lower than that of the first power supply negative signal VSS2. This allows the current flowing through the second transistor T2 to be more easily directed to the third power supply line during the writing phase, thus better preventing the current flowing through the second transistor T2 from flowing to the light-emitting unit 40 during the writing phase.
[0042] In one embodiment, the second power line and the third power line are the same power line.
[0043] It should be noted that the second and third power lines are the same power line, which can reduce the number of transmission lines required for the light-emitting circuit.
[0044] In one embodiment, the light-emitting circuit further includes a switch control line, which is electrically connected to the control terminal of the first switch unit 10, the control terminal of the second switch unit 20, and the control terminal of the third switch unit 30.
[0045] It should be noted that the control terminals of the first switching unit 10, the second switching unit 20, and the third switching unit 30 can share the same switching control line, which can further reduce the number of transmission lines required for the light-emitting circuit.
[0046] In one embodiment, the first switching unit 10 is a third transistor, the first terminal of which is electrically connected to the charging terminal, the second terminal of which is electrically connected to the first terminal of the first capacitor C1, the second terminal of the second transistor T2, the gate of the first transistor T1, and the gate of the second transistor T2, and the gate of the third transistor is electrically connected to the switch control line; the second switching unit 20 is a fourth transistor, the first terminal of which is electrically connected to the second terminal of the first capacitor C1, the second terminal of which is electrically connected to the first terminal of the current source 70, and the gate of which is electrically connected to the switch control line; the third switching unit 30 is a fifth transistor, the first terminal of which is electrically connected to the first terminal of the first transistor T1, the second terminal of which is electrically connected to the second terminal of the first transistor T1, and the gate of which is electrically connected to the switch control line.
[0047] It should be noted that in this embodiment, the first switching unit 10, the second switching unit 20 and the third switching unit 30 are respectively constructed as a thin-film transistor, which makes it easier to construct the light-emitting circuit in the display panel.
[0048] In one embodiment, this embodiment provides a display panel that includes a plurality of light-emitting circuits as described in at least one of the above embodiments.
[0049] It is understood that the display panel provided in this embodiment, since it includes the light-emitting circuit of at least one of the above embodiments, can also control the current flowing through the first switch unit 10 to flow through the first capacitor C1, the second switch unit 20 and the third switch unit 30 to the third power line by simultaneously turning on the first switch unit 10, the second switch unit 20 and the third switch unit 30 during the writing stage, and control the current flowing through the third switch unit 30 and the second transistor T2 to flow through the first capacitor C1, the second switch unit 20 and the current source 70 to the third power line, thus avoiding the current flowing to the light-emitting unit 40 during the writing stage. This can reduce power consumption without changing the potential transmitted by the first power line. By simultaneously turning off the first switch unit 10, the second switch unit 20 and the third switch unit 30 during the light-emitting stage, the current flowing through the first transistor T1 and the second transistor T2 can be controlled to flow through the light-emitting unit 40 to the second power line. Since the current passes through the two channels of the first transistor T1 and the second transistor T2, the current flowing through the light-emitting unit 40 is reduced, which can reduce the adverse effects of parasitic capacitance and wire resistance on these two transistors.
[0050] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.
[0051] The light-emitting circuit and display panel provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A light-emitting circuit, characterized in that, The light-emitting circuit includes: A first transistor, wherein the first terminal of the first transistor is electrically connected to a first power supply line; The second transistor has its first terminal electrically connected to the second terminal of the first transistor. A light-emitting unit, wherein a first end of the light-emitting unit is electrically connected to the second electrode of the second transistor, and a second end of the light-emitting unit is electrically connected to a second power supply line; A first switching unit, wherein a first end of the first switching unit is electrically connected to a charging end, and a second end of the first switching unit is electrically connected to the gate of the first transistor, the gate of the second transistor, and the second electrode of the second transistor. A first capacitor, wherein a first terminal of the first capacitor is electrically connected to a second terminal of the first switching unit; The second switching unit has its first terminal electrically connected to the second terminal of the first capacitor. A current source, wherein a first terminal of the current source is electrically connected to a second terminal of the second switching unit, and a second terminal of the current source is electrically connected to a third power supply line; and A third switching unit, wherein a first terminal of the third switching unit is electrically connected to the first electrode of the first transistor, and a second terminal of the third switching unit is electrically connected to the second electrode of the first transistor; In this configuration, the first switching unit, the second switching unit, and the third switching unit are synchronously turned on during the writing phase to control the current flowing through the first switching unit to flow through the first capacitor, the second switching unit, and the current source to the third power line, and to control the current flowing through the third switching unit and the second transistor to flow through the first capacitor, the second switching unit, and the current source to the third power line; during the light-emitting phase, the first switching unit, the second switching unit, and the third switching unit are synchronously turned off to control the current flowing through the first transistor and the second transistor to flow through the light-emitting unit to the second power line; the first transistor is a low-leakage thin-film transistor, and the second transistor is a high-mobility thin-film transistor.
2. The light-emitting circuit according to claim 1, characterized in that, The light-emitting circuit also includes: A first compensation unit, electrically connected to the gate of the first transistor, is used to reduce the threshold voltage drift of the first transistor; and The second compensation unit is electrically connected to the gate of the second transistor to reduce the threshold voltage drift of the second transistor.
3. The light-emitting circuit according to claim 1, characterized in that, The charging terminal is used to transmit data signals, and the light-emitting unit includes a light-emitting device, which is an organic light-emitting diode, a micro light-emitting diode, a mini light-emitting diode, or a quantum dot light-emitting diode.
4. The light-emitting circuit according to claim 1, characterized in that, The first power line is used to transmit a positive power signal, the second power line is used to transmit a first negative power signal, and the third power line is used to transmit a second negative power signal, wherein the potential of the second negative power signal is lower than the potential of the first negative power signal.
5. The light-emitting circuit according to claim 1, characterized in that, The second power line and the third power line are the same power line.
6. The light-emitting circuit according to claim 1, characterized in that, The light-emitting circuit also includes a switch control line, which is electrically connected to the control terminal of the first switch unit, the control terminal of the second switch unit, and the control terminal of the third switch unit.
7. The light-emitting circuit according to claim 6, characterized in that, The first switching unit is a third transistor. The first terminal of the third transistor is electrically connected to the charging terminal. The second terminal of the third transistor is electrically connected to the first terminal of the first capacitor, the second terminal of the second transistor, the gate of the first transistor, and the gate of the second transistor. The gate of the third transistor is electrically connected to the switch control line. The second switching unit is a fourth transistor. The first terminal of the fourth transistor is electrically connected to the second terminal of the first capacitor, the second terminal of the fourth transistor is electrically connected to the first terminal of the current source, and the gate of the fourth transistor is electrically connected to the switch control line. The third switching unit is a fifth transistor. The first terminal of the fifth transistor is electrically connected to the first terminal of the first transistor, the second terminal of the fifth transistor is electrically connected to the second terminal of the first transistor, and the gate of the fifth transistor is electrically connected to the switch control line.
8. A display panel, characterized in that, The display panel includes a plurality of light-emitting circuits as described in any one of claims 1 to 7.