CN115050321B - Pixel circuit, pixel circuit driving method and display device - Google Patents
Pixel circuit, pixel circuit driving method and display device Download PDFInfo
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- CN115050321B CN115050321B CN202210694793.6A CN202210694793A CN115050321B CN 115050321 B CN115050321 B CN 115050321B CN 202210694793 A CN202210694793 A CN 202210694793A CN 115050321 B CN115050321 B CN 115050321B
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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]
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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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
Abstract
The present disclosure relates to a pixel circuit, a pixel circuit driving method, and a display device. The pixel circuit comprises a light-emitting circuit, a voltage comparator, an AND gate circuit and a first switch element, wherein a first input end of the voltage comparator is connected with a reference line for providing a reference signal, a second input end of the voltage comparator is connected with a total power line for providing a total power signal, and an output end of the voltage comparator is connected with a first input end of the AND gate circuit; the second input end of the AND gate circuit is connected with a data line for providing a data signal; the first switching element is used for responding to an output signal of the output end of the AND gate circuit so as to conduct a light-emitting path of the light-emitting circuit. According to the display device, the light-emitting circuit is isolated when the display device is turned on or off, the interference of charge discharge on the light-emitting circuit is avoided, abnormal conditions such as picture flicker are avoided, and the picture effect of turning on or off is improved.
Description
Technical Field
The application belongs to the technical field of display, and particularly relates to a pixel circuit, a pixel circuit driving method and a display device.
Background
At present, when the OLED display device is turned on or off, there is a possibility that abnormal conditions such as flickering occur in a display screen due to possible charge interference in a display panel.
Disclosure of Invention
The disclosure aims to provide a pixel circuit, a pixel circuit driving method and a display device, which can isolate a light-emitting circuit when the display device is started and shut down, avoid the interference of charge discharge on the light-emitting circuit, avoid abnormal conditions such as picture flicker and the like, and improve the picture effect of starting and shutting down.
The first aspect of the present disclosure discloses a pixel circuit comprising a light emitting circuit, the pixel circuit further comprising a voltage comparator, an and circuit and a first switching element, wherein,
the first input end of the voltage comparator is connected with a reference line for providing a reference signal, the second input end of the voltage comparator is connected with a total power line for providing a total power signal, and the output end of the voltage comparator is connected with the first input end of the AND gate circuit;
the second input end of the AND gate circuit is connected with a data line for providing a data signal;
the first switching element is used for responding to an output signal of the output end of the AND gate circuit so as to conduct a light-emitting path of the light-emitting circuit.
In one exemplary embodiment of the present disclosure, the light emitting circuit includes a second switching element, a driving transistor, a capacitive structure, and a light emitting element, wherein,
the second switching element is used for responding to a scanning signal provided by a scanning signal line so as to connect the data line with a control end of the driving transistor;
the first end of the capacitor structure is connected with the control end of the driving transistor, and the second end of the capacitor structure is connected with the first end of the light-emitting element;
the first switching element is used for responding to an output signal of the output end of the AND gate circuit so as to connect the second end of the driving transistor with the second end of the light-emitting element;
the first end of the driving transistor is connected with the first power supply signal end, and the first end of the light-emitting element is connected with the second power supply signal end.
In an exemplary embodiment of the present disclosure, the pixel circuit further includes a third switching element and a fourth switching element, wherein,
the third switching element is used for responding to the output signal of the output end of the AND gate circuit so as to connect a grid high level line for providing a grid high level signal with the control end of the first switching element;
the fourth switching element is used for responding to an output signal of the output end of the voltage comparator so as to connect the grid high-level line with the scanning signal line.
In an exemplary embodiment of the present disclosure, the pixel circuit further includes an encoder, an input terminal of the encoder is connected to the data line, and an output terminal of the encoder is connected to the second input terminal of the and circuit.
In an exemplary embodiment of the present disclosure, the first to fourth switching elements respectively include first to fourth transistors, wherein,
a first end of the first transistor is connected with a second end of the driving transistor, and a second end of the first transistor is connected with a second end of the light-emitting element;
the control end of the second transistor is also connected with a scanning signal line for providing the scanning signal, the first end of the second transistor is connected with the data line, and the second end of the second transistor is connected with the first end of the capacitor structure and the control end of the driving transistor;
the control end of the third transistor is connected with the output end of the AND gate circuit, the first end of the second transistor is connected with the grid high-level line, the second end of the second transistor is connected with the first end of the pull-down resistor and the control end of the first transistor, and the second end of the pull-down resistor is connected with the second power supply signal end;
the control end of the fourth transistor is connected with the output end of the voltage comparator, the first end of the fourth transistor is connected with the scanning signal line, and the second end of the fourth transistor is connected with the grid high-level line.
In an exemplary embodiment of the disclosure, the driving transistor, the first transistor, the second transistor and the third transistor are all N-type thin film transistors, and the fourth transistor is a P-type thin film transistor; wherein, the liquid crystal display device comprises a liquid crystal display device,
the first power signal provided by the first power signal end is a direct current high level signal, the first power signal is provided by the total power signal, and the second power signal provided by the second power signal end is a direct current low level signal.
In an exemplary embodiment of the present disclosure, the light emitting element is an organic light emitting diode, an anode of the organic light emitting diode is connected to the second terminal of the first transistor, and a cathode of the organic light emitting diode is connected to the second power signal terminal.
A second aspect of the present disclosure discloses a pixel circuit driving method for driving the pixel circuit, the pixel driving method comprising:
in the starting-up stage, the first switching element is turned off by utilizing the total power supply signal;
and in the shutdown stage, the first switching element is turned off by utilizing the total power supply signal.
In an exemplary embodiment of the disclosure, the pixel circuit further includes an encoder, an input terminal of the encoder being connected to the data signal, an output terminal of the encoder being connected to a second input terminal of the and circuit; the pixel driving method further includes:
in a non-black picture display stage, the first switching element is turned on by using the total power supply signal and an output signal of an output end of the encoder;
and in the black picture display stage, the first switching element is turned off by utilizing the total power supply signal and the output signal of the output end of the encoder.
A third aspect of the present disclosure discloses a display device, including a pixel unit and the pixel circuit, where the pixel circuit corresponds to the pixel unit one by one.
The scheme of the application has the following beneficial effects:
according to the method, the voltage comparator, the AND gate circuit and the first switching element are arranged, and the voltage values of the total power supply signal and the reference signal are compared, so that the first switching element is controlled to disconnect the light-emitting path of the light-emitting circuit no matter what state the data signal is in before the voltage of the total power supply signal climbs to the reference signal voltage in the starting-up stage and after the voltage of the total power supply signal drops to the reference signal voltage in the shutting-down stage, the light-emitting path of the light-emitting circuit is isolated, the influence of electric charges on the light-emitting circuit is avoided, the flicker condition of pictures is avoided, and the on-off effect is improved.
Other features and advantages of the present application will be apparent from the following detailed description, or may be learned in part by the practice of the application.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure. It will be apparent to those of ordinary skill in the art that the drawings in the following description are merely examples of the disclosure and that other drawings may be derived from them without undue effort.
Fig. 1 shows a schematic block diagram of a pixel circuit according to an embodiment of the disclosure.
Fig. 2 shows a schematic diagram of a pixel circuit according to an embodiment of the disclosure.
Fig. 3 shows a flowchart of a pixel driving method according to the second embodiment of the present disclosure.
Fig. 4 shows an equivalent circuit diagram of the start-up phase of fig. 2.
Fig. 5 shows an equivalent circuit diagram of the non-black screen stage of fig. 2.
Fig. 6 shows an equivalent circuit diagram of the black screen display stage of fig. 2.
Fig. 7 shows an equivalent circuit diagram of the shutdown phase of fig. 2.
Reference numerals illustrate:
11. a first switching element; 12. a second switching element; 13. a third switching element; 14. a fourth switching element; 21. a data line; 22. a reference line; 23. a main power line;
l, a light-emitting element; C. a capacitor structure; r, pull-down resistor; DT and a driving transistor; t1, a first transistor; t2, a second transistor; t3, third transistor; t4, fourth transistor; sn, a scanning signal; vdd, first power supply signal; vss, a second power supply signal; data, data signals; vref, reference signal; vin, total power supply signal; VGH, gate high signal; u1, a voltage comparator; u2, AND gate circuit; u3, encoder.
Detailed Description
Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments may be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art.
Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the present application. One skilled in the relevant art will recognize, however, that the aspects of the application can be practiced without one or more of the specific details, or with other methods, components, devices, steps, etc. In other instances, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the application.
The present application is further described in detail below with reference to the drawings and specific examples. It should be noted that the technical features of the embodiments of the present application described below may be combined with each other as long as they do not collide with each other. The embodiments described below by referring to the drawings are exemplary and intended for the purpose of explaining the present application and are not to be construed as limiting the present application.
Example 1
Referring to fig. 1, an embodiment of the present disclosure provides a pixel circuit including a light emitting circuit, a voltage comparator U1, an and circuit U2, and a first switching element 11.
It should be understood that the and circuit U2 is a basic logic gate circuit for performing and calculating, and has a plurality of input terminals and an output terminal, where the output terminal outputs a high level only when all the input terminals input a high level at the same time, and otherwise the output terminal outputs a low level; in this embodiment, the and circuit U2 has a first input terminal, a second input terminal, and an output terminal.
The voltage comparator U1 compares the magnitudes of two input voltages and outputs high and low levels according to the comparison result, whereby the voltage comparator U1 has a first input terminal, a second input terminal, and an output terminal.
The light emitting circuit is used for emitting light, and has a light emitting path, and it is understood that the light emitting path is cut off, and the light emitting circuit does not emit light.
The relationship among the voltage comparator U1, the and gate circuit U2, the first switching element 11, and the light emitting circuit is as follows.
The first input end of the voltage comparator U1 is connected with a reference line 22 for providing a reference signal Vref, the second input end of the voltage comparator U1 is connected with a total power line 23 for providing a total power signal Vin, and the output end of the voltage comparator U1 is connected with the first input end of the AND gate circuit U2.
A second input terminal of the and circuit U2 is connected to a Data line 21 for providing a Data signal Data.
The first switching element 11 is configured to respond to an output signal of the output terminal of the and circuit U2 to turn on a light emitting path of the light emitting circuit.
In the embodiment of the disclosure, in the startup phase and the shutdown phase of the display device, the total power supply signal Vin voltage has a rising and falling process, and before rising to the reference signal Vref voltage or after beginning to fall from the reference signal Vref voltage, the current in the display device is unstable, and the charge discharge may cause the luminescence of the luminescence circuit to flicker, resulting in abnormal pictures. In this application, by setting the voltage comparator U1, the and circuit U2 and the first switching element 11, the voltage values of the total power signal Vin and the reference signal Vref are compared, so that the voltage of the total power signal Vin climbs to the voltage of the reference signal Vref in the start-up stage, and the voltage of the total power signal Vin drops to the voltage of the reference signal Vref in the shutdown stage, no matter what state the Data signal Data is in, the and circuit U2 is controlled to disconnect the light-emitting path of the first switching element 11 to enable the light-emitting circuit, thereby isolating the light-emitting circuit, avoiding the influence of charges on the light-emitting circuit, avoiding the occurrence of flicker condition in the picture, and improving the on-off effect.
Specifically, the light emitting circuit includes a second switching element 12, a driving transistor DT, a capacitor structure C, and a light emitting element L. Wherein the second switching element 12 is configured to respond to a scan signal Sn supplied from a scan signal line to connect the data line 21 with a control terminal of the driving transistor DT;
a first end of the capacitor structure C is connected with a control end of the driving transistor DT, and a second end of the capacitor structure C is connected with a first end of the light-emitting element L;
the first switching element 11 is configured to respond to an output signal of the output terminal of the and circuit U2 to connect the second terminal of the driving transistor DT and the second terminal of the light emitting element L, so as to turn on a light emitting path of the light emitting circuit;
the first end of the driving transistor DT is connected to a first power signal terminal, the first power signal terminal provides a first power signal Vdd, the first end of the light emitting element L is connected to a second power signal terminal, and the second power signal terminal provides a second power signal Vss.
The first switching element 11 is arranged between the second end of the driving transistor DT and the second end of the light emitting element L, so that the circuit connection between the driving transistor DT and the light emitting element L is disconnected through the first switching element 11 in the switching-on and switching-off stage, the light emitting element L is isolated, the light emitting element L is not influenced by other electric charges of the circuit, and a flicker phenomenon does not occur in the switching-on and switching-off stage, so that the switching-on and switching-off display effect is improved.
Further, in order to avoid that the output signal at the output end of the and circuit U2 cannot drive the first switching element 11, the pixel circuit further includes a third switching element 13 and a fourth switching element 14.
Wherein the third switching element 13 is configured to respond to an output signal of an output terminal of the and circuit U2 to connect a gate high level line providing a gate high level signal VGH to a control terminal of the first switching element 11; the output terminal of the and circuit U2 is boosted by the third switching element 13, and the first switching element 11 is driven by the gate high-level signal VGH. Of course, in some display devices such as mobile phones and flat panels, the third switching element 13 and the gate high-level line may not be provided to boost the voltage, and the output terminal of the and circuit U2 may directly drive the first switching element 11.
The fourth switching element 14 is configured to respond to an output signal at an output end of the voltage comparator U1, so as to connect the gate high-level line with the scan signal line, thereby, in a switching-on stage, the voltage of the scan signal Sn provided by the scan signal line is raised by the gate high-level line, so that the second switching element 12 is turned on, all the second switching elements 12 controlled by the scan signal Sn in the display device are turned on, and when the display device is turned on, the whole display panel is released with charges, and the charges are neutralized to be released, so that the phenomenon that the panel is lighted in advance due to residual charges when the display device is turned on, or a flashing screen is caused when the display device is turned off is avoided, but no matter how the charges are released from the front end of the first switching element 11, the light-emitting element L is not affected, so that the picture of the switching-on and the switching-off is normal is ensured, and the picture effect of the switching-on and the switching-off is greatly improved.
The pixel circuit further includes an encoder U3, an input terminal of the encoder U3 is connected to the data line 21, and an output terminal of the encoder U3 is connected to a second input terminal of the and circuit U2; the encoder U3 is configured to encode the Data signal Data, where the Data signal Data is a black picture signal, the Data signal Data is to be encoded by the encoder U3, the encoder U3 outputs a low level signal, and similarly, the Data signal Data is a non-black picture signal, the Data signal Data is to be encoded by the encoder U3, and the encoder U3 outputs a high level signal.
Through setting up encoder U3, can be when display device shows the black picture, output low level signal through encoder U3, make the output of AND gate circuit U2 not receive any other interference output low level signal, can control first switch element 11 and be in the off-state, thereby make light emitting element L realize completely closing, the display device realizes complete black picture, the display effect is better, when showing non-black picture, display device can normally show.
The first switching element 11 comprises a first transistor T1, the second switching element 12 comprises a second transistor T2, the third switching element 13 comprises a third transistor T3, and the fourth switching element 14 comprises a fourth transistor T4, as examples.
It should be understood that the first transistor T1, the second transistor T2, the third transistor T3, and the fourth transistor T4 are identical to the driving transistor DT, and each have a first terminal, a second terminal, and a control terminal. The control terminal of each transistor corresponds to the gate of the transistor, one of the first and second terminals corresponds to the source of the transistor, and the other corresponds to the drain of the transistor.
For example, the driving transistor DT, the first transistor T1, the second transistor T2, the third transistor T3, and the fourth transistor T4 according to the embodiments of the present disclosure may be oxide thin film transistors, that is: the active layer of each transistor may be made of oxide, for example, metal oxide materials such as IZGO (Indium Gallium Zinc Oxide, indium zinc oxide) and the like may be adopted, and compared with a-Si (amorphous silicon) thin film transistors, the IGZO thin film transistors have 3 major advantages in performance, namely high precision, low power consumption and high touch performance, and the main targets of the supplies are tablet computers and super-book electronic display products.
In addition, compared with a Low Temperature Polysilicon (LTPS) thin film transistor, the IGZO thin film transistor does not need to crystallize the semiconductor layer by irradiating laser, and thus has the characteristic of easily enlarging the size of the glass substrate.
For example, each transistor may be bottom gate, i.e.: the gate electrode of the transistor is located below the active layer (on the side close to the glass substrate) to enable appropriate thinning of the product, but not limited thereto, each transistor may be a top gate as appropriate.
In addition, each transistor may be an enhancement or depletion transistor, as embodiments of the present disclosure are not particularly limited in this regard.
For example, the driving transistor DT, the first transistor T1, the second transistor T2, and the third transistor T3 in the pixel circuit may be N-type thin film transistors, the fourth transistor T4 is a P-type thin film transistor, the driving voltages of the driving transistor DT and the first to third transistors T3 are high-level voltages, and the driving voltage of the fourth transistor T4 is low-level voltages. Based on this, the first power signal Vdd provided by the first power signal terminal may be a dc high level signal, the first power signal Vdd may be provided by a total power signal Vin, which is a total input power signal driven by the whole display device and the circuit, and when the total power signal Vin climbs to be stable, the first power signal Vdd is also synchronously stable, and the second power signal Vss provided by the second power signal terminal may be a dc low level signal.
The light emitting element L may be a current driven light emitting element L which emits light by being controlled by a current flowing through the driving transistor DT, for example, the light emitting element L may be an Organic Light Emitting Diode (OLED), and the pixel circuit may be applied to an OLED display device.
In the pixel circuit, the first end of the light emitting element L is the cathode of the organic light emitting diode, and the second end of the light emitting element L is the anode of the organic light emitting diode, so that the cathode of the organic light emitting diode is connected with the second power supply signal end, and the anode of the organic light emitting diode is connected with the second end of the first transistor T1.
The connection relation of each structure in the pixel circuit is described in detail below with reference to fig. 2.
The first end of the first transistor T1 is connected to the second end of the driving transistor DT, and the second end of the first transistor T1 is connected to the second end of the light emitting element L.
The control end of the second transistor T2 is further connected to a scan signal line for providing a scan signal Sn, the first end of the second transistor T2 is connected to the data line 21, and the second end of the second transistor T2 is connected to the first end of the capacitor structure C and the control end of the driving transistor DT.
The control end of the third transistor T3 is connected with the output end of the AND gate circuit U2, the first end of the second transistor T2 is connected with the grid high level line, the second end of the second transistor T2 is connected with the first end of the pull-down resistor R and the control end of the first transistor T1, and the second end of the pull-down resistor R is connected with the second power supply signal end. The pull-down resistor R is used for controlling pull-down, and the resistance value can be selected according to actual use, and in this embodiment, can be 10K ohms.
The control end of the fourth transistor T4 is connected to the output end of the voltage comparator U1, the first end of the fourth transistor T4 is connected to the scan signal line, and the second end of the fourth transistor T4 is connected to the gate high-level line.
Based on this, the pixel circuit of the embodiment of the disclosure can perform isolation protection on the light-emitting element L in the power-on stage, the power-off stage and the black picture display stage, no matter how the front end releases the electric charge, the extinction process of the light-emitting element L is not affected, and when the black picture is displayed, the complete black picture can be realized, and the display effect is greatly improved.
Example two
Based on the pixel circuit mentioned in the first embodiment, the second embodiment of the disclosure further provides a pixel circuit driving method, and in combination with fig. 3, the pixel circuit driving method includes:
in step S100, the first switching element 11 is turned off by the total power signal Vin during the power-on stage.
In step S200, in the non-black screen display stage, the first switching element 11 is turned on by the total power signal Vin and the output signal of the output terminal of the encoder U3.
In step S300, in the black frame display stage, the first switching element 11 is turned off by the total power signal Vin and the output signal of the output terminal of the encoder U3.
In step S400, the first switching element 11 is turned off by the total power signal Vin during the shutdown phase.
The pixel circuit driving method is described in detail below.
Referring to fig. 4, in the start-up stage, the voltage of the reference signal Vref is set to be close to the voltage of the total power signal Vin, when the voltage of the total power signal Vin gradually climbs after the start-up, when the voltage of the total power signal Vin is smaller than the voltage of the reference signal Vref, the output terminal of the voltage comparator U1 outputs a low level signal, no matter what state the scanning signal Sn and the Data signal Data are in, the output terminal of the and circuit U2 outputs a low level, the third transistor T3 is in a turned-off state, the control terminal of the first transistor T1 corresponds to the connection with the second power signal terminal, the first transistor T1 is in a turned-off state at this time, the light emitting element L is isolated, the fourth transistor T4 is in a turned-on state, the gate high level line is connected with the scanning signal line, and the scanning signal Sn is pulled up to a gate high level, so that all the second transistors T2 in the display device are in a turned-on state, and the charges of the whole screen are fully released, but the light emitting element L is in a state that is not emitting light because it has been isolated.
When the voltage of the total power supply signal Vin is greater than the voltage of the reference signal Vref, the output end of the voltage comparator U1 outputs a high level signal, the encoder U3 outputs the high level signal by default, so that the and gate circuit U2 outputs the high level signal, the third transistor T3 is in a conducting state, the control end of the first transistor T1 is connected with the gate high level line, so that the first transistor T1 is in a conducting state, the fourth transistor T4 is in a closing state, the second transistor T2 is controlled to be turned on and off by the scan signal Sn, the light emitting circuit starts to emit light, and the startup is completed.
Referring to fig. 5, in the stage of displaying the non-black picture, the encoder U3 encodes the Data signal Data and outputs a high level signal, and when the output end of the voltage comparator U1 outputs the high level signal, the and gate circuit U2 outputs the high level signal to make the first transistor T1 be in a conductive state, and the light emitting circuit controls the light emitting state by the scan signal Sn to display the non-black picture.
Referring to fig. 6, in the black frame display stage, the encoder U3 encodes the Data signal Data and outputs a low level signal, and at this time, the output end of the voltage comparator U1 outputs the low level signal, and the and circuit U2 outputs the low level signal, so that the first transistor T1 is in the off state, the light emitting element L is isolated, and the light emitting element L is completely turned off, thereby realizing the display of a completely black frame.
Referring to fig. 7, in the shutdown phase, when the voltage of the total power signal Vin is gradually reduced after shutdown, and when the voltage of the total power signal Vin is smaller than the voltage of the reference signal Vref, as can be seen by referring to the aforementioned startup phase, the charges of the entire screen are sufficiently released, but the light emitting element L is in a non-light emitting state due to the isolation thereof, and no flicker phenomenon occurs.
Example III
Based on the foregoing content of the first embodiment, the third embodiment also provides a display device, which may be an OLED display device. The display device may include pixel units and pixel circuits in the embodiment, where the pixel circuits are in one-to-one correspondence with the pixel units. Since the pixel circuit in the first embodiment is provided in the present embodiment, the display device has all the advantages of the pixel circuit in the first embodiment, and will not be described herein.
The display device of the embodiment of the disclosure can be an Active-matrix organic light-emitting diode (AMOLED) display, has the advantages of thin body, power saving, bright color, high image quality and the like, and is widely applied. Such as: OLED televisions, mobile phones, notebook screens, etc., are increasingly dominant in the flat panel display field.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
In this application, unless explicitly stated and limited otherwise, the terms "mounted," "connected," and the like are to be construed broadly, and may be, for example, fixedly attached, detachably attached, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.
In the description of the present specification, reference to the terms "some embodiments," "exemplary," and the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
While embodiments of the present application have been shown and described, it should be understood that the above embodiments are illustrative and not to be construed as limiting the application, and that variations, modifications, alternatives and variations may be made to the embodiments by one of ordinary skill in the art within the scope of the application, and therefore all changes and modifications that fall within the spirit and scope of the invention as defined by the claims and the specification of the application are intended to be covered thereby.
Claims (10)
1. A pixel circuit comprises a light-emitting circuit, and is characterized in that the pixel circuit also comprises a voltage comparator, an AND gate circuit and a first switch element, wherein,
the first input end of the voltage comparator is connected with a reference line for providing a reference signal, the second input end of the voltage comparator is connected with a main power line for providing a main power signal, and the output end of the voltage comparator is connected with the first input end of the AND gate circuit;
the second input end of the AND gate circuit is connected with a data line for providing a data signal;
the first switching element is used for responding to an output signal of the output end of the AND gate circuit so as to conduct a light-emitting path of the light-emitting circuit.
2. The pixel circuit according to claim 1, wherein the light emitting circuit comprises a second switching element, a driving transistor, a capacitor structure, and a light emitting element, wherein,
the second switching element is used for responding to a scanning signal provided by a scanning signal line so as to connect the data line with a control end of the driving transistor;
the first end of the capacitor structure is connected with the control end of the driving transistor, and the second end of the capacitor structure is connected with the first end of the light-emitting element;
the first switching element is used for responding to an output signal of the output end of the AND gate circuit so as to connect the second end of the driving transistor with the second end of the light-emitting element;
the first end of the driving transistor is connected with the first power supply signal end, and the first end of the light-emitting element is connected with the second power supply signal end.
3. The pixel circuit according to claim 2, further comprising a third switching element and a fourth switching element, wherein,
the third switching element is used for responding to the output signal of the output end of the AND gate circuit so as to connect a grid high level line for providing a grid high level signal with the control end of the first switching element;
the fourth switching element is used for responding to an output signal of the output end of the voltage comparator so as to connect the grid high-level line with the scanning signal line.
4. A pixel circuit according to claim 2 or 3, further comprising an encoder, an input of which is connected to the data line, and an output of which is connected to the second input of the and circuit.
5. A pixel circuit according to claim 3, wherein the first to fourth switching elements comprise first to fourth transistors, respectively, and wherein,
a first end of the first transistor is connected with a second end of the driving transistor, and a second end of the first transistor is connected with a second end of the light-emitting element;
the control end of the second transistor is also connected with a scanning signal line for providing the scanning signal, the first end of the second transistor is connected with the data line, and the second end of the second transistor is connected with the first end of the capacitor structure and the control end of the driving transistor;
the control end of the third transistor is connected with the output end of the AND gate circuit, the first end of the second transistor is connected with the grid high-level line, the second end of the second transistor is connected with the first end of the pull-down resistor and the control end of the first transistor, and the second end of the pull-down resistor is connected with the second power supply signal end;
the control end of the fourth transistor is connected with the output end of the voltage comparator, the first end of the fourth transistor is connected with the scanning signal line, and the second end of the fourth transistor is connected with the grid high-level line.
6. The pixel circuit according to claim 5, wherein the driving transistor, the first transistor, the second transistor, and the third transistor are all N-type thin film transistors, and the fourth transistor is a P-type thin film transistor; wherein, the liquid crystal display device comprises a liquid crystal display device,
the first power signal provided by the first power signal end is a direct current high level signal, the first power signal is provided by the total power signal, and the second power signal provided by the second power signal end is a direct current low level signal.
7. The pixel circuit according to claim 5, wherein the light emitting element is an organic light emitting diode, an anode of the organic light emitting diode is connected to the second terminal of the first transistor, and a cathode of the organic light emitting diode is connected to the second power signal terminal.
8. A pixel circuit driving method for driving the pixel circuit according to claim 1, characterized in that the pixel driving method comprises:
in the starting-up stage, the first switching element is turned off by utilizing the total power supply signal;
and in the shutdown stage, the first switching element is turned off by utilizing the total power supply signal.
9. The method according to claim 8, wherein the pixel circuit further includes an encoder, an input terminal of the encoder being connected to the data signal, an output terminal of the encoder being connected to a second input terminal of the and circuit; the pixel driving method further includes:
in a non-black picture display stage, the first switching element is turned on by using the total power supply signal and an output signal of an output end of the encoder;
and in the black picture display stage, the first switching element is turned off by utilizing the total power supply signal and the output signal of the output end of the encoder.
10. A display device comprising a pixel unit and the pixel circuit according to any one of claims 1 to 7, wherein the pixel circuit corresponds to the pixel unit one by one.
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| CN102708795B (en) * | 2012-02-29 | 2014-11-12 | 京东方科技集团股份有限公司 | Gate driver on array unit, gate driver on array circuit and display device |
| CN107305481B (en) * | 2016-04-25 | 2021-05-04 | 中兴通讯股份有限公司 | Method and device for improving display effect of terminal |
| CN106782323A (en) * | 2017-02-15 | 2017-05-31 | 京东方科技集团股份有限公司 | Pixel-driving circuit and its driving method, display device |
| CN109727586A (en) * | 2018-12-29 | 2019-05-07 | 重庆秉为科技有限公司 | A kind of eyes protection display device |
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