CN111508435B - Pixel driving circuit, display panel and terminal equipment - Google Patents
Pixel driving circuit, display panel and terminal equipment Download PDFInfo
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- CN111508435B CN111508435B CN202010353830.8A CN202010353830A CN111508435B CN 111508435 B CN111508435 B CN 111508435B CN 202010353830 A CN202010353830 A CN 202010353830A CN 111508435 B CN111508435 B CN 111508435B
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3233—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the current through the light-emitting element
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0247—Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
Abstract
In the pixel driving circuit, a control end of a driving transistor unit is connected with a compensation transistor unit comprising a double-gate transistor, and an anti-creeping unit is arranged, the anti-creeping unit acts on a middle node of the double-gate transistor, and adjusts a voltage value of the middle node of the double-gate transistor according to a light-emitting control signal, wherein the light-emitting control signal is a signal for controlling a light-emitting device to emit light. Therefore, when the display panel is in a light-emitting stage, the anti-leakage unit responds to the light-emitting control signal, and further adjusts the voltage value of the middle node of the double-gate transistor according to the light-emitting control signal, so that the voltage of the middle node of the double-gate transistor is close to the voltage of the control end of the driving transistor, the electric leakage from the middle node of the double-gate transistor to the control end of the driving transistor is reduced, the phenomenon that the display panel flickers when being recognized by human eyes is avoided, and the practical application requirement is met.
Description
Technical Field
The embodiment of the application relates to the technical field of display panels, in particular to a pixel driving circuit, a display panel and a terminal device.
Background
The pixel driving of the display panel is driven by a pixel driving circuit. The pixel drive circuit modulates light emission by controlling a drive current of the light emitting element.
In the related art, a pixel driving circuit generally includes a driving transistor unit and a compensation transistor unit including a double-gate transistor. The compensation transistor unit is used for controlling the control end of the driving transistor unit to be communicated with other ends of the driving transistor unit, so that the light-emitting element emits light.
For the display panel, the higher the refresh frequency of the display panel, the better the image quality display, and the more the power consumption, so that the refresh frequency of the display panel can be set to a low frequency when the high quality image quality is not required, and the refresh frequency of the display panel can be set to a high frequency when the high quality image quality is required, thereby achieving the balance between the image quality and the power consumption. However, in the pixel driving circuit, at a low frequency, the intermediate node of the dual-gate transistor leaks current to the control terminal of the driving transistor, so that the normal light emission of the light emitting element cannot be ensured, and the display panel screen flickers. The intermediate node of the double-gate transistor may be a connection point between the drain of one transistor and the source of the other transistor in the two common-gate transistors, or a connection point between the source of one transistor and the drain of the other transistor.
Disclosure of Invention
The embodiment of the application provides a pixel driving circuit, a display panel and a terminal device, and the pixel driving circuit can solve the problem that an intermediate node of a double-gate transistor leaks electricity to a control end of a driving transistor.
In a first aspect, an embodiment of the present application provides a pixel driving circuit, including:
a driving transistor unit driving a light emitting device, a first end of the driving transistor unit being connected to a first voltage source, a second end of the driving transistor unit being connected to a first end of the light emitting device, and a second end of the light emitting device being connected to a second voltage source;
the compensation transistor unit comprises a double-gate transistor, wherein a first end of the compensation transistor unit is connected with the control end of the driving transistor unit, and a second end of the compensation transistor unit is connected with a second end of the driving transistor unit and used for controlling the communication between the control end of the driving transistor unit and the second end of the driving transistor unit;
and the anti-creeping unit acts on the middle node of the double-gate transistor and adjusts the voltage value of the middle node of the double-gate transistor according to a light-emitting control signal, wherein the light-emitting control signal is a signal for controlling the light-emitting device to emit light.
Optionally, the anti-leakage unit includes a transistor, a control end of the transistor is connected to the light emission control signal, a first end of the transistor is connected to the control end of the driving transistor unit, and a second end of the transistor is connected to the middle node of the double-gate transistor.
Optionally, the anti-leakage unit includes a capacitor;
the first end of the capacitor is connected with the light-emitting control signal, and the second end of the capacitor is connected with the middle node of the double-grid transistor.
Optionally, the circuit further includes:
a first light emitting control transistor unit;
the control end of the first light-emitting control transistor unit is connected with the light-emitting control signal, the first end of the first light-emitting control transistor unit is connected with the first voltage source, and the second end of the first light-emitting control transistor unit is connected with the first end of the driving transistor unit and used for controlling the communication between the first voltage source and the first end of the driving transistor unit.
Optionally, the circuit further includes:
a second light emission control transistor unit;
the control end of the second light-emitting control transistor unit is connected with the light-emitting control signal, the first end of the second light-emitting control transistor unit is connected with the second end of the driving transistor unit, and the second end of the second light-emitting control transistor unit is connected with the first end of the light-emitting device and used for controlling the communication between the second end of the driving transistor unit and the first end of the light-emitting device.
Optionally, the circuit further includes:
a storage capacitor unit;
the first end of the storage capacitor unit is connected with the control end of the driving transistor unit, and the second end of the storage capacitor unit is connected with the first voltage source.
Optionally, the circuit further includes:
a reset transistor unit;
the first end of the reset transistor unit is connected with the control end of the driving transistor unit, and the second end of the reset transistor unit is connected with the first end of the light-emitting device and used for controlling initial voltage to be written into the control end of the driving transistor unit and the first end of the light-emitting device.
Optionally, the circuit further includes:
a data write transistor unit;
the first end of the data writing transistor unit is connected with a data line, and the second end of the data writing transistor unit is connected with the first end of the driving transistor unit and used for providing data voltage on the data line to the first end of the driving transistor unit.
In a second aspect, embodiments of the present application provide a display panel including a pixel driving circuit provided in the first aspect of the embodiments of the present application or in various possible designs of the first aspect.
In a third aspect, an embodiment of the present application provides a terminal device, which includes a processing device, a storage device, and the display panel provided in the second aspect of the embodiment of the present application.
In the pixel driving circuit, the control terminal of the driving transistor unit is connected to a compensation transistor unit including a dual-gate transistor, and an anti-leakage unit is provided, the anti-leakage unit acts on a middle node of the dual-gate transistor, and adjusts a voltage value of the middle node of the dual-gate transistor according to a light emission control signal, where the light emission control signal is a signal for controlling the light emission of the light emitting device. Therefore, when the display panel is in a light-emitting stage, the anti-leakage unit responds to the light-emitting control signal, and further adjusts the voltage value of the middle node of the double-gate transistor according to the light-emitting control signal, so that the voltage of the middle node of the double-gate transistor is close to the voltage of the control end of the driving transistor, thereby reducing the leakage of the middle node of the double-gate transistor to the control end of the driving transistor, avoiding the phenomenon that the display panel screen flickers recognized by human eyes, and meeting the practical application requirement.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
Fig. 1 is a schematic structural diagram of a pixel driving circuit according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of another pixel driving circuit according to an embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of another pixel driving circuit according to an embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of another pixel driving circuit according to an embodiment of the present disclosure;
fig. 5 is a schematic structural diagram of another pixel driving circuit according to an embodiment of the present disclosure;
fig. 6 is a schematic structural diagram of another pixel driving circuit according to an embodiment of the present disclosure;
fig. 7 is a schematic structural diagram of another pixel driving circuit according to an embodiment of the present disclosure;
FIG. 8 is a driving timing diagram corresponding to the pixel driving circuit structure shown in FIG. 6;
fig. 9 is a schematic structural diagram of a display panel according to an embodiment of the present disclosure;
fig. 10 is a schematic structural diagram of a terminal device according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The transistors used in all embodiments of the present application can be transistors, thin film transistors, or field effect transistors or other devices with the same characteristics. In the embodiment of the present application, in order to distinguish two terminals of the transistor except for the control terminal, one of the poles is referred to as a first terminal, and the other pole is referred to as a second terminal.
When the transistor is a triode, the control end can be a base electrode, the first end can be a collector electrode, and the second end can be an emitter electrode; alternatively, the control terminal may be a base, the first terminal may be an emitter, and the second terminal may be a collector.
When the transistor is a thin film transistor or a field effect transistor, the control end can be a grid electrode, the first end can be a drain electrode, and the second end can be a source electrode; alternatively, the control terminal may be a gate, the first terminal may be a source, and the second terminal may be a drain.
The pixel driving of the display panel is driven by a pixel driving circuit, which typically includes a driving transistor unit and a compensation transistor unit including a double-gate transistor. The compensation transistor unit is used for controlling the control end of the driving transistor unit to be communicated with other ends of the driving transistor unit, so that the light-emitting element emits light.
For the display panel, the larger the number of refreshes of the image displayed on the display panel, the smaller the flicker of the image display and the higher the picture quality. That is, the refresh frequency of the display panel is high, and the image quality display is better, but the power consumption is also high. Therefore, when high-quality image quality is not required, the refresh frequency of the display panel can be set to a low frequency, and when high-quality image quality is required, the refresh frequency of the display panel can be set to a high frequency, thereby achieving balance between image quality and power consumption.
However, when the display panel operates at a low frequency (the refresh frequency is relatively low), the intermediate node of the dual-gate transistor leaks current to the control terminal of the driving transistor, for example, in the circuit shown in fig. 1, when the driving signal provided by the gate line of the dual-gate transistor M31 and M32 jumps upwards during low-frequency display, the intermediate node of M31 and M32 is pulled high, and during one frame time, the node leaks current to the gate of the driving transistor M1, so that the potential of the driving transistor M1 rises, and the luminance of the light-emitting element decreases.
Therefore, the embodiment of the present application proposes a concept that: since the middle node of the double-gate transistor is pulled high and leaks to the gate of the driving transistor, an anti-leakage unit may be provided for adjusting the voltage value of the middle node of the double-gate transistor in response to the emission control signal in the emission phase, for example, when the display panel operates at a low frequency, the voltage value of the middle node of the double-gate transistor is lowered in response to the emission control signal, so that the voltage of the middle node of the double-gate transistor approaches the voltage of the control terminal of the driving transistor. Therefore, no matter how the driving signal provided by the grid line of the double-grid transistor changes, the voltage value of the middle node of the double-grid transistor can be adjusted through the anti-leakage unit, so that the problem that the middle node of the double-grid transistor leaks electricity to the control end of the driving transistor is solved, and the phenomenon that human eyes recognize that the display panel screen flickers is avoided.
It should be noted that the refresh frequency of the display panel is relatively high frequency or low frequency, the high frequency may be a specific value or a frequency range, and similarly, the low frequency may be a specific value or a frequency range, which is not limited in this application.
Fig. 2 is a schematic structural diagram of another pixel driving circuit according to an embodiment of the present disclosure. As shown in fig. 2, the pixel driving circuit provided in the embodiment of the present application includes: a driving transistor unit 210 driving the light emitting device D, a compensation transistor unit 220 including a double gate transistor 221, and an anti-leakage unit 230.
The first terminal of the driving transistor unit 210 is connected to a first voltage source VDD, the second terminal thereof is connected to a first terminal of the light emitting device D, and the second terminal thereof is connected to a second voltage source VSS.
A first terminal of the compensation transistor unit 220 is connected to the control terminal of the driving transistor unit 210, and a second terminal of the compensation transistor unit 220 is connected to the second terminal of the driving transistor unit 210, for controlling the communication between the control terminal of the driving transistor unit 210 and the second terminal of the driving transistor unit 210.
The anti-leakage unit 230 acts on the middle node of the dual-gate transistor 221, and adjusts the voltage value of the middle node of the dual-gate transistor 221 according to a light emission control signal, which is a signal for controlling the light emitting device D to emit light.
For the pixel driving circuit shown in fig. 2, the operation principle is as follows: when the driving transistor unit 210 and the light emitting device D are connected in series between the first voltage source VDD and the second voltage source VSS, the driving transistor unit 210 is turned on and a path is formed between the first voltage source VDD and the second voltage source VSS, the light emitting device D emits light, and when the driving transistor unit 210 is in an off state, the light emitting device D does not emit light. The compensation transistor unit 220 controls the connection between the control terminal of the driving transistor unit 210 and the second terminal of the driving transistor unit 210 under the control of the driving signal provided by the gate line.
When the display panel displays at low frequency, because the driving signal provided by the grid line of the double-grid transistor jumps upwards, the middle node of the double-grid transistor is pulled high, and the node leaks electricity to the grid electrode of the driving transistor in one frame time, so that the potential of the driving transistor is increased, and the brightness of the light-emitting element is reduced. Therefore, the problem of leakage of the intermediate node of the dual-gate transistor to the control terminal of the driving transistor needs to be solved, and the phenomenon that human eyes recognize that the display panel screen flickers is avoided.
For the circuit shown in fig. 2, the control terminal of the driving transistor unit 210 is connected to a compensation transistor unit 220, which includes a double gate transistor 221. The circuit further includes a leakage preventing unit 230, the leakage preventing unit 230 acting on the middle node of the dual-gate transistor 221, wherein the leakage preventing unit 230 adjusts the voltage value of the middle node of the dual-gate transistor 221 in relation to the light emission control signal, that is, the leakage preventing unit 230 can adjust the voltage value of the middle node of the dual-gate transistor 221 in accordance with the light emission control signal, for example, when the display panel operates at a low frequency, the leakage preventing unit 230 decreases the voltage value of the middle node of the dual-gate transistor in response to the light emission control signal to make the voltage of the middle node of the dual-gate transistor approach the voltage of the control terminal of the driving transistor. In this way, the voltage value of the middle node of the dual-gate transistor 221 can be adjusted by the anti-leakage unit 230 regardless of the variation of the driving signal provided by the gate line of the dual-gate transistor 220, thereby solving the problem of leakage of the middle node of the dual-gate transistor to the control terminal of the driving transistor.
In the pixel driving circuit, the control terminal of the driving transistor unit is connected to a compensation transistor unit including a dual-gate transistor, and an anti-leakage unit is provided, the anti-leakage unit acts on a middle node of the dual-gate transistor to adjust a voltage value of the middle node of the dual-gate transistor according to a light emission control signal, wherein the light emission control signal is a signal for controlling the light emission of the light emitting device. Therefore, when the display panel is in a light-emitting stage, the anti-leakage unit responds to the light-emitting control signal, and further adjusts the voltage value of the middle node of the double-gate transistor according to the light-emitting control signal, so that the voltage of the middle node of the double-gate transistor is close to the voltage of the control end of the driving transistor, thereby reducing the leakage of the middle node of the double-gate transistor to the control end of the driving transistor, avoiding the phenomenon that the display panel screen flickers recognized by human eyes, and meeting the practical application requirement.
Fig. 3 is a schematic structural diagram of another pixel driving circuit according to an embodiment of the present disclosure. As shown in fig. 3, in the embodiment shown in fig. 2, the anti-leakage unit 230 includes a transistor M8, a control terminal of the transistor M8 is connected to the emission control signal, a first terminal of the transistor M8 is connected to the control terminal of the driving transistor unit 210, and a second terminal of the transistor M8 is connected to the middle node of the dual-gate transistor 220.
The control terminal of the transistor M8 is connected to the emission control line EM for controlling the connection between the control terminal of the driving transistor unit 210 and the middle node of the dual gate transistor 220 under the control of the emission control signal provided by the emission control line EM.
For the pixel driving circuit shown in fig. 3, the operation principle is as follows: the compensation transistor unit 220 controls the connection between the control terminal of the driving transistor unit 210 and the second terminal of the driving transistor unit 210 under the control of the driving signal provided by the gate line, and the light emitting device D emits light, wherein the control terminal of the driving transistor unit 210 and the middle node of the dual-gate transistor 221 are connected through the transistor M8, and the control terminal of the transistor M8 is connected to the light emitting control signal, so that when the refresh frequency of the display panel changes, the transistor M8 adjusts the voltage value of the middle node of the dual-gate transistor 221 according to the light emitting control signal, the voltage of the middle node of the dual-gate transistor 221 is made to approach the voltage of the control terminal of the driving transistor 210, the leakage of the middle node of the dual-gate transistor to the control terminal of the driving transistor is reduced, and the phenomenon of screen flicker of the display panel is improved.
Illustratively, the current change of the pixel drive circuit within one frame is obtained before and after the pixel drive circuit sets the transistor M8 described above. Before the transistor M8 is not provided, the current drops by 1.6% in one frame. After the transistor M8 is set, the current drops by 0.56% in one frame. Therefore, it is known that the transistor M8 is disposed in the pixel driving circuit, so that the problem of leakage from the middle node of the dual-gate transistor to the control terminal of the driving transistor can be effectively solved, and further, the phenomenon of flicker of the display panel screen is prevented from being recognized by human eyes, thereby meeting the requirements of practical application.
Fig. 4 is a schematic structural diagram of another pixel driving circuit according to an embodiment of the present disclosure. As shown in fig. 4, in any of the above embodiments, the anti-leakage unit 230 includes a capacitor C1, a first terminal of the capacitor C1 is connected to the emission control signal, and a second terminal of the capacitor C1 is connected to the middle node of the dual-gate transistor 221.
For the pixel driving circuit shown in fig. 4, the operation principle is as follows: the compensation transistor unit 220 controls the connection between the control terminal of the driving transistor unit 210 and the second terminal of the driving transistor unit 210 under the control of the driving signal provided by the gate line, and the light emitting device D emits light. When the driving signal provided by the gate line of the compensation transistor unit 220 makes a transition upward, the capacitor C1 couples the potential of the intermediate node of the dual-gate transistor 221 downward through the above-mentioned light emission control signal making a transition downward, thereby reducing the leakage of the intermediate node to the control terminal of the driving transistor unit 210 within one frame and improving the flicker phenomenon of the display panel screen.
Illustratively, the current change of the pixel driving circuit is obtained within one frame before and after the pixel driving circuit sets the capacitor C1. Before the capacitor C1 was not provided, the current dropped by 1.6% in one frame. After the capacitor C1 was set, the current dropped by 0.05% in one frame. Therefore, it is known that the capacitor C1 is disposed in the pixel driving circuit, so that the problem of leakage from the middle node of the dual-gate transistor to the control terminal of the driving transistor can be effectively solved, and further, the phenomenon of flicker of the display panel screen is prevented from being recognized by human eyes, thereby meeting the requirements of practical applications.
Fig. 5 is a schematic structural diagram of another pixel driving circuit according to an embodiment of the present disclosure. As shown in fig. 5, on the basis of any of the above embodiments, the pixel driving circuit further includes: the first light emitting control transistor unit 240.
The control end of the first light emitting control transistor unit 240 is connected to the light emitting control line EM, the first end is connected to the first voltage source VDD, and the second end is connected to the first end of the driving transistor unit 210, and is configured to control the connection between the first voltage source VDD and the first end of the driving transistor unit 210 under the control of the light emitting control signal provided by the light emitting control line EM.
In some embodiments, continuing to fig. 5, the pixel drive circuit further comprises: the second light emission controlling transistor unit 250.
The control terminal of the second emission control transistor unit 250 is connected to the emission control line EM, the first terminal is connected to the second terminal of the driving transistor unit 210, and the second terminal is connected to the first terminal of the light emitting device, so as to control the connection between the second terminal of the driving transistor unit 210 and the first terminal of the light emitting device under the control of the emission control signal provided by the emission control line EM.
In some embodiments, continuing to fig. 5, the pixel drive circuit further comprises: the storage capacitor unit 260. A first terminal of the storage capacitor unit 260 is connected to the control terminal of the driving transistor unit 210, and a second terminal of the storage capacitor unit 260 is connected to the first voltage source VDD.
Here, the storage capacitor 260 is used to maintain the voltage signal at the control terminal of the driving transistor 210 stable, so that the light emitting luminance of the light emitting element remains unchanged.
In some embodiments, continuing to fig. 5, the pixel drive circuit further comprises: the transistor unit 270 is reset. The control terminal of the reset transistor unit 270 is connected to the reset control terminal, the first output terminal is connected to the control terminal of the driving transistor unit 210, and the second output terminal of the reset transistor unit 270 is connected to the first terminal of the light emitting device D, so as to control writing of the initial voltage into the control terminal of the driving transistor unit 210 and the first terminal of the light emitting device D under the control of the reset control signal provided by the control terminal.
In some embodiments, continuing to fig. 5, the pixel drive circuit further comprises: data is written to the transistor cell 280. The control terminal of the Data writing transistor unit 280 is connected to the gate line, the first terminal is connected to the Data line Data, and the second terminal is connected to the first terminal of the driving transistor unit 210, for providing the Data voltage on the Data line Data to the first terminal of the driving transistor unit 210 under the control of the driving signal provided by the gate line.
The following describes the embodiments of the present application with reference to a specific example.
Fig. 6 is a schematic structural diagram of another pixel driving circuit according to an embodiment of the present disclosure. As shown in fig. 6, the driving Transistor unit 210 includes a P-type Thin Film Transistor (TFT), which is denoted as a driving Transistor M1; the compensation transistor unit 220 includes a double-gate transistor, which is denoted as a double-gate transistor M31& M32; the data writing transistor unit 280 includes a P-type TFT denoted as a data writing transistor M5; the reset transistor unit 270 includes two P-type TFTs, denoted as a first reset transistor M4 and a second reset transistor M7; the first and second light emission controlling transistor units 240 and 250 respectively include a P-type TFT, which is denoted as a first light emission controlling transistor M2 and a second light emission controlling transistor M6; the anti-creeping unit 230 includes a P-type TFT denoted as a transistor M8; the storage capacitor unit 260 includes a fixed capacitor CST.
As shown in fig. 6, the connection relationship of the pixel driving circuit is:
the gate of the first light emission controlling transistor M2 is connected to the light emission control line EM, the source of the first light emission controlling transistor M2 is connected to the first voltage source VDD, and the drain of the first light emission controlling transistor M2 is electrically connected to the source of the driving transistor M1. An emission control signal EM _ N supplied from the emission control line EM.
A gate of the second light emission controlling transistor M6 is connected to the light emission control line EM, a source of the second light emission controlling transistor M6 is connected to the drain of the driving transistor M1, and a drain of the second light emission controlling transistor M6 is connected to the anode of the light emitting device D; the Light Emitting device D may be an Organic Light-Emitting Diode (OLED), for example. An emission control signal EM _ N supplied from the emission control line EM.
The gate of the Data writing transistor M5 is connected to the gate line, the source of the Data writing transistor M5 is connected to the Data line Data, and the drain of the Data writing transistor M5 is connected to the source of the driving transistor M1; the Data line Data is used for providing a Data signal VDATA, and the gate line provides a second scan signal S2_ N.
A first terminal of the storage capacitor CST is connected to the gate of the driving transistor M1, and a second terminal of the storage capacitor CST is connected to the first voltage source VDD.
The gate of the compensation control transistor 220 is connected to the gate line, the drain of the compensation control transistor 220 is connected to the gate of the driving transistor M1, and the source of the compensation control transistor 220 is connected to the drain of the driving transistor M1. The gate line provides a second scan signal S2_ N.
The gate of the first reset transistor M4 is connected to the reset control terminal, the source of the first reset transistor M4 is connected to the initial voltage VREF, and the drain of the first reset transistor M4 is connected to the gate of the driving transistor M1. The reset control terminal provides a first scan signal S1_ N.
The gate of the second reset transistor M7 is connected to the reset control terminal, the source of the second reset transistor M7 is connected to the initial voltage VREF, and the drain of the second reset transistor M7 is connected to the anode of the light emitting device D. The reset control terminal provides a first scan signal S1_ N.
The gate of the transistor M8 is connected to the emission control line EM, the source of the transistor M8 is connected to the intermediate node of the double gate transistors M31& M32, and the drain of the transistor M8 is connected to the control terminal of the driving transistor cell M1. The emission control line EM supplies an emission control signal EM _ N.
For the pixel driving circuit shown in fig. 6, the operation principle is as follows:
when the EM is turned on and the light emitting device D starts emitting light, the transistor M8 controls the connection between the middle node of the dual-gate transistor M31& M32 and the gate of the driving transistor M1 under the control of the light emitting control signal EM _ N provided by the light emitting control line EM, and keeps the voltage consistent, thereby reducing the problem of leakage of the middle node of the M31& M32 to the gate of the driving transistor M1, further, avoiding the phenomenon that human eyes recognize that the display panel screen flickers, and meeting the practical application requirements.
Fig. 7 is a schematic structural diagram of another pixel driving circuit according to the embodiment of the present disclosure, and as shown in fig. 7, the driving transistor unit 210 includes a P-type TFT, which is denoted as a driving transistor M1; the compensation transistor unit 220 includes a double-gate transistor, which is denoted as a double-gate transistor M31& M32; the data writing transistor unit 280 includes a P-type TFT denoted as a data writing transistor M5; the reset transistor unit 270 includes two P-type TFTs, denoted as a first reset transistor M4 and a second reset transistor M7; the first and second light emission controlling transistor units 240 and 250 respectively include a P-type TFT, which is denoted as a first light emission controlling transistor M2 and a second light emission controlling transistor M6; the anti-leakage unit 230 includes a capacitor, denoted as capacitor C1; the storage capacitor unit 260 includes a fixed capacitor CST.
The connection relationship among the first light emission control transistor M2, the second light emission control transistor M6, the data writing transistor M5, the storage capacitor CST, the compensation control transistor 220, the first reset transistor M4 and the second reset transistor M7 is described with reference to fig. 6, and is not repeated herein.
A first terminal of the capacitor C1 is connected to the emission control line EM, and a second terminal of the capacitor C2 is connected to the intermediate node of the double gate transistors M31& M32. The emission control line EM supplies an emission control signal EM _ N.
Alternatively, the first terminal of the capacitor C1 is connected to the control terminal of the first light emission controlling transistor unit M2, or the first terminal of the capacitor C1 is connected to the control terminal of the second light emission controlling transistor unit M6.
For the pixel driving circuit shown in fig. 7, the operation principle is as follows:
when the EM is turned on and the light emitting device D starts emitting light, the capacitor C1 couples the potential of the intermediate node of the dual-gate transistors M31& M32 downward under the control of the light emitting control signal EM _ N provided by the light emitting control line EM, thereby reducing the leakage of the intermediate node to the gate of the driving transistor M1 within one frame, and further avoiding the phenomenon that human eyes recognize that the display panel screen flickers, and meeting the requirements of practical application.
Note that, in the pixel driver circuit of the present application, some or all of the elements may be replaced with another element or a combination of a plurality of elements as long as the function of the element can be achieved.
Taking fig. 6 as an example, fig. 8 is a driving timing diagram corresponding to the pixel driving circuit structure shown in fig. 6. As shown in fig. 8, the driving timing includes three stages, a first stage (initialization stage T1), a second stage (data writing stage T2), and a third stage (light emitting stage T3).
In the first phase (initialization phase T1), the emission control signal EM _ N and the second scan signal S2_ N are at a high level, and the first scan signal S1_ N is at a low level. The light emission control signal EM _ N controls the first light emission control transistor M2 and the first light emission control transistor M6 to be turned off; the second scan signal S2_ N controls the data write transistor M5, the dual gate transistors M31& M32 to be turned off; the first scan signal S1_ N controls the first reset transistor M4 to be turned on, and the initial voltage VREF initializes the gate of the driving transistor M1, so as to ensure that the driving transistor M1 is in a conducting state during the data writing phase T2; the first scan signal S1_ N controls the second reset transistor M7 to be turned on, and the initial voltage VREF initializes the anode of the light emitting device D.
In the second phase (data writing phase T2), the data signal VDATA corresponding to the light emission luminance of the light emitting device D is supplied. The emission control signal EM _ N and the first scan signal S1_ N are high level, and the second scan signal S2_ N is low level. The light emission control signal EM _ N controls the first light emission control transistor M2 and the first light emission control transistor M6 to be turned off; the first scan signal S1_ N controls the first reset transistor M4 and the second reset transistor M7 to be turned off; the second scan signal S2_ N controls the data write transistor M5 and the dual gate transistors M31& M32 to be turned on to write the data signal VDATA into the gate of the driving transistor M1 via the source and drain of the driving transistor M1. The gate voltage of the driving transistor M1 gradually rises and the data writing phase is completed when VDATA + Vth is written. (at the end of the write, S2_ N turns off the upward transition, resulting in the coupling of the middle node potential of the double-gate transistor upward)
In the third phase (light-emitting phase T3), the first and second scan signals S1_ N and S2_ N are at a high level, and the light-emitting control signal EM _ N is at a low level. The first scan signal S1_ N controls the first reset transistor M4 and the second reset transistor M7 to be turned off; the second scan signal S2_ N controls the data write transistor M5 and the dual gate transistors M31& M32 to be turned off; the light emission control signal EM _ N controls the first light emission control transistor M2 and the first light emission control transistor M6 to be turned on, the gate voltage of the driving transistor M1 is VDATA + Vth, and the source voltage applies the first power VDD, so that a driving current is generated and flows into the anode of the light emitting device D, driving the light emitting device D to emit light.
It should be noted that fig. 6 to 8 only illustrate the transistors as P-type TFTs, but the transistors may also be N-type TFTs besides P-type TFTs, for example, the driving transistor unit 210 includes an N-type TFT, which is referred to as a driving transistor M1, and the present application is not limited thereto.
Fig. 9 is a schematic structural diagram of a display panel according to an embodiment of the present application, where the display panel includes a pixel driving circuit according to any embodiment of the present application. The pixel driving circuit includes a Gate line voltage input terminal Gate and a Data voltage input terminal Data. The display panel further includes: a scan driving circuit 910, a data driving circuit 920, a plurality of scan lines (S1, S2, S3, S4 … …), and a plurality of data lines (D1, D2, D3, D4 … …). The port of the scan driving circuit 910 is electrically connected to a plurality of scan lines, the Gate line voltage input terminal Gate of the pixel driving circuit is electrically connected to one scan line, and the Data voltage input terminal of the pixel driving circuit is electrically connected to one Data line.
It should be noted that the Data voltage input terminal Data and the Gate line voltage input terminal Gate of the pixel circuit for driving one sub-pixel are only schematically shown in the figure, and the ports of the pixel circuits for driving the other sub-pixels are similar to the sub-pixel and are not shown one by one here.
The display panel provided by the embodiment of the application has the same beneficial effects as the pixel driving circuit provided by any embodiment of the application.
Fig. 10 is a schematic structural diagram of a terminal Device according to an embodiment of the present disclosure, and as shown in fig. 10, the terminal Device may include, but is not limited to, a mobile terminal such as a mobile phone, a notebook computer, a Digital broadcast receiver, a Personal Digital Assistant (PDA), a tablet computer (PAD), a Portable Multimedia Player (PMP), a vehicle-mounted terminal (e.g., a car navigation terminal), and a fixed terminal such as a Digital TV, a desktop computer, and the like. The terminal device shown in fig. 10 is only an example, and should not bring any limitation to the functions and the scope of use of the embodiments of the present disclosure.
As shown in fig. 10, the terminal device may include a processing means (e.g., a central processing unit, a graphic processor, etc.) 1001 that can perform various appropriate actions and processes according to a program stored in a Read Only Memory (ROM) 1002 or a program loaded from a storage means 1008 into a Random Access Memory (RAM) 1003. In the RAM1003, various programs and data necessary for the operation of the terminal device are also stored. The processing device 1001, the ROM1002, and the RAM1003 are connected to each other by a bus 1004. An input/output (I/O) interface 1005 is also connected to bus 1004.
Generally, the following devices may be connected to the I/O interface 1005: input devices 1006 including, for example, a touch screen, touch pad, keyboard, mouse, camera, microphone, accelerometer, gyroscope, etc.; a Display panel 1007 including, for example, a Liquid Crystal Display (LCD), an Organic Light Emitting Display (OLED), and the like; storage devices 1008 including, for example, magnetic tape, hard disk, and the like; and a communication device 1009. The communication means 1009 may allow the terminal device to perform wireless or wired communication with other devices to exchange data.
For the present application, the RAM1003 stores corresponding relations between different refresh frequencies of the display panel 1007 and the common voltage COM, and when the refresh frequency of the display panel 1007 of the terminal device changes, the processing device 1001 acquires the corresponding relation between the refresh frequency stored in the RAM1003 and the common voltage COM according to the refresh frequency of the current display panel 1007, and acquires a value of the common voltage COM, so that the display panel 1007 realizes variable frequency display.
It should be noted that although fig. 10 shows a terminal device having various means, it is to be understood that it is not required to implement or have all the means shown. More or fewer devices may alternatively be implemented or provided.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.
Claims (9)
1. A pixel driving circuit, comprising:
a driving transistor unit driving a light emitting device, a first end of the driving transistor unit being connected to a first voltage source, a second end of the driving transistor unit being connected to a first end of the light emitting device, and a second end of the light emitting device being connected to a second voltage source;
the compensation transistor unit comprises a double-gate transistor, wherein a first end of the compensation transistor unit is connected with the control end of the driving transistor unit, and a second end of the compensation transistor unit is connected with a second end of the driving transistor unit and used for controlling the communication between the control end of the driving transistor unit and the second end of the driving transistor unit;
the anti-creeping unit acts on the middle node of the double-gate transistor and adjusts the voltage value of the middle node of the double-gate transistor according to a light-emitting control signal, wherein the light-emitting control signal is a signal for controlling the light-emitting device to emit light;
the anti-creeping unit comprises a transistor, wherein the control end of the transistor is connected with the light-emitting control signal, the first end of the transistor is connected with the control end of the driving transistor unit, and the second end of the transistor is connected with the middle node of the double-grid transistor.
2. The circuit of claim 1, wherein the anti-creeping unit comprises a capacitor;
the first end of the capacitor is connected with the light-emitting control signal, and the second end of the capacitor is connected with the middle node of the double-grid transistor.
3. The circuit of claim 1, further comprising:
a first light emitting control transistor unit;
the control end of the first light-emitting control transistor unit is connected with the light-emitting control signal, the first end of the first light-emitting control transistor unit is connected with the first voltage source, and the second end of the first light-emitting control transistor unit is connected with the first end of the driving transistor unit and used for controlling the communication between the first voltage source and the first end of the driving transistor unit.
4. The circuit of claim 1, further comprising:
a second light emission control transistor unit;
the control end of the second light-emitting control transistor unit is connected with the light-emitting control signal, the first end of the second light-emitting control transistor unit is connected with the second end of the driving transistor unit, and the second end of the second light-emitting control transistor unit is connected with the first end of the light-emitting device and used for controlling the communication between the second end of the driving transistor unit and the first end of the light-emitting device.
5. The circuit of claim 1, further comprising:
a storage capacitor unit;
the first end of the storage capacitor unit is connected with the control end of the driving transistor unit, and the second end of the storage capacitor unit is connected with the first voltage source.
6. The circuit of claim 1, further comprising:
a reset transistor unit;
the first end of the reset transistor unit is connected with the control end of the driving transistor unit, and the second end of the reset transistor unit is connected with the first end of the light-emitting device and used for controlling initial voltage to be written into the control end of the driving transistor unit and the first end of the light-emitting device.
7. The circuit of claim 1, further comprising:
a data write transistor unit;
the first end of the data writing transistor unit is connected with a data line, and the second end of the data writing transistor unit is connected with the first end of the driving transistor unit and used for providing data voltage on the data line to the first end of the driving transistor unit.
8. A display panel comprising the pixel drive circuit according to any one of claims 1 to 7.
9. A terminal device characterized by comprising processing means, storage means, and the display panel of claim 8.
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| CN202010353830.8A CN111508435B (en) | 2020-04-29 | 2020-04-29 | Pixel driving circuit, display panel and terminal equipment |
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| CN112216244B (en) * | 2020-10-30 | 2022-04-29 | 武汉天马微电子有限公司 | Display panel, driving method thereof and display module |
| CN113314073B (en) | 2021-05-17 | 2022-04-08 | 上海天马微电子有限公司 | Display panel and display device |
| CN115148153A (en) * | 2021-05-17 | 2022-10-04 | 上海天马微电子有限公司 | Display panel and display device |
| CN113362758B (en) * | 2021-06-03 | 2022-12-06 | 武汉华星光电半导体显示技术有限公司 | Drive circuit and display panel |
| KR20230049794A (en) | 2021-10-06 | 2023-04-14 | 삼성디스플레이 주식회사 | Pixel and display device including pixel |
| CN114120920B (en) * | 2021-11-29 | 2022-12-16 | 武汉天马微电子有限公司 | Pixel circuit, driving method thereof, display panel and display device |
| CN114067720A (en) * | 2021-12-03 | 2022-02-18 | 武汉华星光电半导体显示技术有限公司 | Pixel circuit and display device |
| CN117423315B (en) * | 2023-12-19 | 2024-04-16 | 维信诺科技股份有限公司 | Pixel circuit and display panel |
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| US10032413B2 (en) * | 2015-05-28 | 2018-07-24 | Lg Display Co., Ltd. | Organic light emitting display |
| KR20180061860A (en) * | 2016-11-30 | 2018-06-08 | 엘지디스플레이 주식회사 | Thin film transistor and display panel using the same |
| CN108847186B (en) * | 2018-06-29 | 2021-05-25 | 昆山国显光电有限公司 | Pixel circuit, driving method thereof, display panel and display device |
| CN110648629B (en) * | 2019-10-31 | 2023-09-22 | 厦门天马微电子有限公司 | Display panel, manufacturing method thereof and display device |
| CN110767163B (en) * | 2019-11-08 | 2021-01-26 | 京东方科技集团股份有限公司 | Pixel circuit and display panel |
| CN111179859B (en) * | 2020-03-16 | 2021-03-02 | 京东方科技集团股份有限公司 | Pixel circuit, display panel and display device |
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