CN110867160B - Pixel circuit, driving method thereof and display panel - Google Patents
Pixel circuit, driving method thereof and display panel Download PDFInfo
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- CN110867160B CN110867160B CN201810981008.9A CN201810981008A CN110867160B CN 110867160 B CN110867160 B CN 110867160B CN 201810981008 A CN201810981008 A CN 201810981008A CN 110867160 B CN110867160 B CN 110867160B
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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]
Abstract
The invention discloses a pixel circuit, a driving method thereof and a display panel, wherein the pixel circuit comprises a first transistor, a second transistor, a third transistor, a driving transistor, a first capacitor, a second capacitor and an organic light-emitting element; the control end of the first transistor is electrically connected with the first scanning signal input end of the pixel circuit; the control end of the second transistor is electrically connected with the first light-emitting control signal input end of the pixel circuit; the control end of the third transistor is electrically connected with the second light-emitting control signal input end of the pixel circuit; the first pole of the first capacitor is electrically connected with the data signal input end of the pixel circuit, and the second pole of the first capacitor is electrically connected with the second end of the first transistor. The embodiment of the invention is beneficial to improving the pixel density; and the first capacitor and the second capacitor are arranged in the pixel circuit, so that the adjustment range of the voltage of the data signal is expanded, gray scale modulation is facilitated, and the display effect is better.
Description
Technical Field
The embodiment of the invention relates to the technical field of organic light emitting display, in particular to a pixel circuit, a driving method thereof and a display panel.
Background
Organic light emitting display panels are applied more and more widely in the display aspect of mobile phones, watches, etc., and especially, organic light emitting display panels using Low Temperature Polysilicon (LTPS) as a back plate are on a trend of accelerating development.
The organic light emitting display panel includes a pixel circuit for driving the organic light emitting device to emit light, and the display driving circuit is generally composed of a plurality of Thin Film Transistors (TFTs) and a capacitor. For the LTPS backplane, due to the existence of grains and grain boundaries in the polysilicon, the uniformity is poor, and the threshold voltages of the thin film transistors are different. When the pixel circuit taking LTPS as the backboard drives the OLED to emit light, the uniformity of the OLED light emission is poor due to the uneven threshold voltage of the TFT; in addition, as the device ages, the problem of TFT threshold voltage shift becomes more serious, and therefore, it is necessary to compensate for the threshold voltage of the driving TFT in the pixel circuit. The prior pixel circuit usually compensates the threshold voltage of the TFT through a certain current framework, such as the relatively common 7T1C structure. In addition, in order to make the data signal voltage have a wide range in gray scale adjustment, a long channel TFT is generally employed.
However, the circuit architecture of the conventional pixel circuit is complex, and under the development trend that the pixel size is smaller and smaller, the number of TFTs is too large, and the long-channel TFTs are not favorable for drawing a layout and improving the pixel density.
Disclosure of Invention
The invention provides a pixel circuit, a driving method thereof and a display panel, which are used for simplifying the structure of the pixel circuit, improving the pixel density and enabling the voltage of a data signal to have a larger adjusting range.
In a first aspect, an embodiment of the present invention provides a pixel circuit, including a first transistor, a second transistor, a third transistor, a driving transistor, a first capacitor, a second capacitor, and an organic light emitting element;
the control end of the first transistor is electrically connected with the first scanning signal input end of the pixel circuit, the first end of the first transistor is electrically connected with the control end of the driving transistor, and the second end of the first transistor is electrically connected with the second end of the driving transistor;
the first end of the second transistor is electrically connected with the first level signal input end of the pixel circuit, the second end of the second transistor is electrically connected with the first end of the driving transistor, and the control end of the second transistor is electrically connected with the first light-emitting control signal input end of the pixel circuit;
a first end of the third transistor is electrically connected with a second end of the driving transistor, a second end of the third transistor is electrically connected with a first pole of the organic light-emitting element, a control end of the third transistor is electrically connected with a second light-emitting control signal input end of the pixel circuit, and a second pole of the light-emitting element is connected to a second level signal input end of the pixel circuit;
the first electrode of the second capacitor is used for inputting a first reference voltage, and the second electrode of the second capacitor is electrically connected with the control end of the driving transistor;
the first pole of the first capacitor is electrically connected with the data signal input end of the pixel circuit, and the second pole of the first capacitor is electrically connected with the second end of the first transistor.
The first pole of the second capacitor is electrically connected with the first level signal input end.
The first transistor, the second transistor, the third transistor, the fourth transistor and the driving transistor are P-type transistors.
The pixel circuit further comprises a fourth transistor, a control end of the fourth transistor is electrically connected with a second scanning signal input end of the pixel circuit, a first end of the fourth transistor is electrically connected with a reset signal input end of the pixel circuit, and a second end of the fourth transistor is electrically connected with a control end of the driving transistor.
In one frame of display, the signal input by the data signal input end comprises a first pulse signal.
In a frame of display, the input signal of the first light-emitting control signal input end comprises two second pulse signals, the latter second pulse signal of the two second pulse signals is overlapped with the first pulse signal, and the width of the second pulse signal is larger than that of the first pulse signal.
In a second aspect, an embodiment of the present invention further provides a display panel, including the pixel circuit provided in the first aspect.
In a third aspect, an embodiment of the present invention further provides a driving method for a pixel circuit, including:
in the reset stage, a first control signal is input to the first scanning signal input end and the second light-emitting control signal input end, the first transistor and the third transistor are conducted, and the potential of the first electrode of the organic light-emitting element is written into the control end of the driving transistor through the conducted first transistor;
in the write compensation stage, a first control signal is input to the input end of the first light-emitting control signal, and the second transistor is conducted; inputting a first control signal to a first scanning signal input end, and enabling a first transistor; the first reference voltage is written into the control end of the driving transistor through the conducted second transistor, the driving transistor and the first transistor, and when the voltage difference between the control end of the driving transistor and the first end is equal to the threshold voltage of the driving transistor, the driving transistor is cut off; in the reset stage and the write compensation stage, a second reference voltage is input to the data signal input end;
in the data writing stage, an input signal of the data signal input end jumps to a data signal voltage from a second reference voltage, and the second reference voltage is transmitted to a first polar plate of the first capacitor; inputting a second control signal to the first light-emitting control signal input end, and stopping the second transistor;
a light emitting stage, wherein a first control signal is input to the first light emitting control signal input end, and the second transistor is conducted; the first control signal is input to the second light-emitting control signal input end, the third transistor is conducted, and the driving transistor drives the organic light-emitting element to emit light.
In a fourth aspect, an embodiment of the present invention further provides another driving method for a pixel circuit, including:
in the first reset stage, a first control signal is input to the second scanning signal input end, the fourth transistor is conducted, and a reset signal input by the reset signal input end is transmitted to the control end of the driving transistor through the conducted fourth transistor;
in the second reset stage, a first control signal is input to the first scanning signal input end, the first transistor is conducted, and a reset signal input by the reset signal input end is transmitted to the second end of the driving transistor through the conducted fourth transistor and the first transistor;
in the write compensation stage, a first control signal is input to the input end of the first light-emitting control signal, and the second transistor is conducted; inputting a first control signal to a first scanning signal input end, and enabling a first transistor; the first reference voltage is written into the control end of the driving transistor through the conducted second transistor, the driving transistor and the first transistor, and when the voltage difference between the control end of the driving transistor and the first end is equal to the threshold voltage of the driving transistor, the driving transistor is cut off; the data signal input end inputs a second reference voltage;
in the data writing stage, an input signal of the data signal input end jumps to a data signal voltage from a second reference voltage, and the second reference voltage is transmitted to a first polar plate of the first capacitor; inputting a second control signal to the first light-emitting control signal input end, and stopping the second transistor;
a light emitting stage, wherein a first control signal is input to the first light emitting control signal input end, and the second transistor is conducted; the first control signal is input to the second light-emitting control signal input end, the third transistor is conducted, and the driving transistor drives the organic light-emitting element to emit light.
Before the light-emitting stage, a holding stage is further included, and in the holding stage, the signal input by the data signal input end jumps to a second reference voltage from the data signal voltage.
Before the signal input by the data signal input end jumps to the second reference voltage from the data signal voltage, the second control signal is input by the first scanning signal input end, and the first transistor is turned off.
The first control signal is a low level signal, and the second control signal is a high level signal.
The pixel circuit comprises a first transistor, a second transistor, a third transistor, a fourth transistor, a driving transistor, a first capacitor, a second capacitor and an organic light-emitting element, the number of transistors and the number of signal lines in the pixel circuit are reduced on the basis of compensating the threshold voltage of the driving transistor, the domain drawing of the pixel circuit is facilitated, the area of the pixel circuit is reduced, and the pixel density is improved; and the first capacitor and the second capacitor are arranged in the pixel circuit, so that the adjustment range of the voltage of the data signal is expanded, gray scale modulation is facilitated, and the display effect is better.
Drawings
Fig. 1 is a schematic structural diagram of a pixel circuit according to an embodiment of the present invention.
Fig. 2 is a timing diagram of an operation of a pixel circuit according to an embodiment of the present invention.
Fig. 3 is a structural diagram of another pixel circuit according to an embodiment of the present invention.
Fig. 4 is a timing diagram illustrating an operation of another pixel circuit according to an embodiment of the present invention.
Fig. 5 is a schematic structural diagram of a display panel according to an embodiment of the present invention.
Fig. 6 is a flowchart of a pixel circuit driving method according to an embodiment of the present invention.
Fig. 7 is a flowchart of another pixel circuit driving method according to an embodiment of the invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic structural diagram of a pixel circuit according to an embodiment of the present invention. Referring to fig. 1, the pixel circuit includes a first transistor T1, a second transistor T2, a third transistor T3, a driving transistor T0, a first capacitor C1, a second capacitor C2, and an organic light emitting element D1; a control terminal of the first transistor T1 is electrically connected to the first scan signal input terminal Sn of the pixel circuit, a first terminal of the first transistor T1 is electrically connected to the control terminal of the driving transistor T0, and a second terminal of the first transistor T1 is electrically connected to the second terminal of the driving transistor T0; a first terminal of the second transistor T2 is electrically connected to the first level signal input terminal ELVDD of the pixel circuit, a second terminal of the second transistor T2 is electrically connected to the first terminal of the driving transistor T0, and a control terminal of the second transistor T2 is electrically connected to the first light emission control signal input terminal En-1 of the pixel circuit; a first terminal of the third transistor T3 is electrically connected to the second terminal of the driving transistor T0, a second terminal of the third transistor T3 is electrically connected to the first pole of the organic light emitting element D1, a control terminal of the third transistor T3 is electrically connected to the second light emission control signal input terminal En of the pixel circuit, and a second pole of the light emitting element is connected to the second level signal input terminal ELVSS of the pixel circuit; a first electrode of the second capacitor C2 is used for inputting a first reference voltage, and a second electrode of the second capacitor C2 is electrically connected with the control terminal of the driving transistor T0; a first pole of the first capacitor C1 is electrically connected to the Data signal input terminal Data of the pixel circuit, and a second pole of the first capacitor C1 is electrically connected to the second terminal of the first transistor T1. As can be seen from the pixel circuit in fig. 1, compared with the common 7T1C pixel circuit structure in the prior art, the pixel circuit has fewer transistors and fewer signal lines, reduces the area of the pixel circuit, is beneficial to layout drawing, and improves the pixel density. Moreover, the pixel circuit comprises two capacitors, wherein the second capacitor C2 is used as a storage capacitor; the first capacitor C1 is arranged to adjust the first capacitor C1 and the second capacitor C2 to expand the adjustment range of the data signal voltage, which is beneficial to gray scale modulation.
The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative work belong to the protection scope of the present invention.
With continued reference to fig. 1, optionally, the first pole of the second capacitor C2 is electrically connected to the first level signal input terminal ELVDD. Specifically, the first level signal input terminal ELVDD is configured to receive an externally input first reference voltage, which may be a relatively high voltage.
Optionally, the first transistor T1, the second transistor T2, the third transistor T3, the fourth transistor T4 and the driving transistor T0 are P-type transistors. In addition, in the technical solution provided in this embodiment, the control end of each transistor is a gate of each transistor, the first end of each transistor is a source of each transistor, and the second end of each transistor is a drain of each transistor.
Fig. 2 is an operation timing diagram of a pixel circuit according to an embodiment of the present invention, where the operation timing diagram is suitable for the pixel circuit shown in fig. 1. Referring to fig. 1 and 2, in particular, the operation timing of the pixel circuit shown in fig. 2 includes a reset phase t1, a write compensation phase t2, a data write phase t3 and a light emitting phase t 4. The first transistor T1, the second transistor T2, the third transistor T3, and the driving transistor T0 in the pixel circuit are exemplified as P-type transistors.
With continuing reference to fig. 1 and fig. 2, in particular, during the reset phase T1, the first scan signal input terminal Sn is inputted as a low level signal, which is transmitted to the control terminal of the first transistor T1 to turn on the first transistor T1; meanwhile, the second light-emitting signal control signal input terminal En of the pixel circuit is inputted with a low level signal, which is transmitted to the control terminal of the third transistor T3, turning on the third transistor T3. At this time, the potential of the first electrode of the organic light emitting element D1 is written to the control terminal of the driving transistor T0 through the turned-on third transistor T3 and first transistor T1, and the gate of the driving transistor T0 is reset. Alternatively, the first electrode of the organic light emitting element D1 is the anode of the organic light emitting element D1. In the reset phase T1, a high level signal is input to the first light-emitting control signal input terminal to control the second transistor T2 to be in an off state.
In the write compensation stage T2, the first light emitting control signal input end En-1 is inputted as a low level signal, the low level signal is transmitted to the control end of the second transistor T2, the second transistor T2 is turned on, the first reference voltage is transmitted to the first end of the driving transistor T0, and the driving transistor T0 is turned on; the first scan signal input terminal Sn receives a low level signal, which is transmitted to the control terminal of the first transistor T1, and the first transistor T1 is turned on. The first reference voltage is written to the control terminal of the driving transistor T0 through the turned-on second transistor T2, driving transistor T0, and first transistor T1, the potential of the control terminal of the driving transistor T0 gradually increases, and the driving transistor T0 is turned off when the control terminal of the driving transistor T0 increases to ELVDD- | Vth | (where ELVDD is the voltage input to the first level signal input terminal and Vth is the threshold voltage of the driving transistor T0). In the reset phase t1 and the write compensation phase t2, the Data signal input terminal Data inputs the second reference voltage.
In the Data writing phase t3, the Data signal input terminal Data input jumps from the second reference voltage to the Data signal voltage, and the Data signal voltage is transmitted to the first plate of the first capacitor C1, and the Data signal voltage is lower than the second reference voltage. The first light-emitting control signal input end En-1 inputs a high level signal, and the second transistor T2 is cut off; the second emission control signal input terminal En is still maintained at the high level during the write compensation period T2, the first scan signal input terminal Sn is still maintained at the low level during the write compensation period T2, the third transistor T3 is turned off, and the first transistor T1 is turned on. Due to the coupling effect of the first capacitor C1, the potential at the control terminal of the driving transistor T0 jumps to
Where, ELVDD is the voltage input from the first level signal input terminal, Vth is the threshold voltage of the driving transistor T0, and Vref isThe second reference voltage, Vdata, is a data signal voltage.
In the light-emitting period T4, the first light-emitting control signal is inputted as a low level signal, the low level signal is transmitted to the control terminal of the second transistor T2, the second transistor T2 is turned on, the first reference voltage is transmitted to the first terminal of the driving transistor T0 through the turned-on second transistor T2, and therefore the control terminal of the driving transistor T0 is at the same voltage level
Therefore, the potential of the control terminal and the first terminal of the driving transistor T0 is greater than the threshold voltage thereof, and the driving transistor T0 is turned on; the second light emitting control signal input terminal En is inputted with a low level signal, which is transmitted to the control terminal of the third transistor T3, and the third transistor T3 is turned on; at this time, the driving transistor T0 generates a driving current I, and the driving current I drives the organic light emitting element D1 to emit light for display. When the organic light emitting element D1 emits light to perform display, according to the current formula:
(where Cox is the gate oxide capacitance (capacitance per unit area of gate oxide, μ is the carrier mobility,
VGS is the voltage difference between the gate and the source of the driving transistor T0 for the width-to-length ratio of the driving transistor T0), it can be obtained,
finally, the method can be obtained,
as can be seen from the current formula of the organic light emitting element D1 calculated as described above, the first capacitor C1 and the second capacitor C2 are provided in the pixel circuit so that the current calculation formula is included in
By the factor of (a) of (b),
so that the adjustable range of the data signal voltage is larger for the same range of drive current. Specifically, the gray scales displayed by the display panel usually include 0 to 255 gray scales, each gray scale corresponds to a driving current range, and for a specific pixel circuit, each gray scale corresponds to a specific voltage range. The current formula through the organic light emitting element D1 obtained according to the conventional pixel circuit structure includes only a factor less than 1, i.e., the aspect ratio
Therefore, for each gray scale, the adjustment range of the data signal voltage is small, so that the data signal voltage is slightly changed, the displayed gray scale is changed, and the display effect is poor; in the current formula obtained by the pixel circuit provided in this embodiment, a factor smaller than 1 is added to the current calculation formula obtained by the conventional pixel circuit
According to the current calculation formula, the (Vref-Vdata) and the factor are in multiplication relation, so that the difference value of the (Vref-Vdata) can be larger for a specific current range, and the voltage variation range of the data signal is expanded. Therefore, the data voltage regulation range corresponding to the current range corresponding to each gray scale is enlarged, so that the modulation of the gray scales is facilitated, and the display effect is better. The capacitance values of the first capacitor C1 and the second capacitor C2 can be set by those skilled in the art according to the display requirements.
The pixel circuit and the corresponding working time sequence thereof provided by the embodiment reduce the number of transistors and the number of signal lines in the pixel circuit, are beneficial to drawing the layout of the pixel circuit, reduce the area of the pixel circuit and are beneficial to improving the pixel density; and the first capacitor C1 and the second capacitor C2 are arranged in the pixel circuit, so that the adjustment range of the data signal voltage is expanded, gray scale modulation is facilitated, and the display effect is better.
On the basis of the above technical solutions, embodiments of the present invention further provide an optional pixel circuit structure. Fig. 3 is a structural diagram of another pixel circuit according to an embodiment of the invention, and referring to fig. 3, the pixel circuit further includes a fourth transistor T4, a control terminal of the fourth transistor T4 is electrically connected to the second scan signal input terminal Sn-1 of the pixel circuit, a first terminal of the fourth transistor T4 is electrically connected to the reset signal input terminal of the pixel circuit, and a second terminal of the fourth transistor T4 is electrically connected to the control terminal of the driving transistor T0.
Specifically, by providing the fourth transistor T4, the reset of the driving transistor T0 is controlled by the fourth transistor T4, and the reset of the driving transistor T0 can be made more accurate. Fig. 4 is an operation timing diagram of another pixel circuit provided in the embodiment of the present invention, which is applicable to the pixel circuit shown in fig. 3. Referring to fig. 3 and 4, the operation timing of the pixel circuit shown in fig. 4 includes: a first reset phase t11, a second reset phase t12, a write compensation phase t2, a data write phase, and a light emission phase t 4. The first transistor T1, the second transistor T2, the third transistor T3, and the driving transistor T0 in the pixel circuit are exemplified as P-type transistors.
Referring to fig. 3 and 4, in detail, in the first reset phase T11, the second scan signal input terminal Sn-1 inputs a low level, the fourth transistor T4 is turned on, and the reset signal input from the reset signal input terminal Vint is transmitted to the control terminal of the driving transistor T0 through the turned-on fourth transistor T4, so as to reset the gate of the driving transistor. In the first reset stage T11, the input of the first lighting control signal input terminal En-1 is at a high level, and the second transistor T2 is turned off; the second emission control signal is inputted at a low level, the third transistor T3 is turned on, and the potential of the second terminal of the driving transistor T0 is equal to the potential of the first electrode of the organic light emitting device D1.
In the second reset period T12, the first scan signal input terminal Sn inputs a low level, and the first transistor T1 is turned on; in the second reset period T12, the fourth transistor T4 is kept in a conducting state, the reset signal input from the reset signal input terminal Vint is transmitted to the second terminal of the driving transistor T0 through the conducting fourth transistor T4 and the conducting first transistor T1, and at this time, the control terminal and the second terminal of the driving transistor T0 have the same potential and are both reset signal voltages, and the reset of the anode of the organic light emitting element D1 is realized. In the second reset stage T12, the input of the first lighting control signal input terminal En-1 is at a high level, and the second transistor T2 is turned off; the second light emission control signal input is low level and the third transistor T3 is turned on.
For the working timing sequence corresponding to the pixel circuit shown in fig. 3 (fig. 4), the working timing sequences of the write compensation stage t2, the data write stage t3 and the light emitting stage t4 are the same as the working timing sequence (fig. 2) and the working process corresponding to the pixel circuit shown in fig. 1, and are not repeated herein.
Referring to fig. 2 and 4, alternatively, in one frame shown, the signal input at the Data signal input terminal Data includes a first pulse signal.
Specifically, in the Data writing phase t3, the Data signal input end Data inputs the first pulse signal, the input of the first pulse signal corresponding to the Data signal input end Data jumps from the second reference voltage to the Data signal voltage, and the Data signal voltage is smaller than the second reference voltage. Due to the coupling effect of the first capacitor C1, the potential of the second pole of the first capacitor C1 changes, and the potential of the control terminal of the driving transistor T0 changes because the first transistor T1 is turned on during the write compensation period T2. Specifically, the potential of the control terminal of the driving transistor T0 becomes
The voltage is greater than ELVDD-Vth | so that when the second transistor T2 is turned on in the light emitting period T4, the driving transistor T0 is turned on to drive the organic light emitting device D1 to emit light. In addition, the pixel circuit is provided with the first capacitor C1 and the second capacitor C2, and the Data signal input end Data inputs the first pulse signal, so that after the input signal of the Data signal input end Data jumps, the current finally flowing through the organic light-emitting element D1 is related to the first capacitor C1 and the second capacitor C2, thereby expanding the Data voltage regulation range and being beneficial to gray scale modulation.
With continued reference to fig. 2 and 4, in a frame shown, the input signal of the first lighting control signal input end En-1 includes two second pulse signals, the latter one of the two second pulse signals overlaps with the first pulse signal, and the width of the second pulse signal is greater than the width of the first pulse signal.
Specifically, in order to prevent the first reference voltage from being input to the second plate of the first capacitor C1 to affect the signal input by the Data signal input terminal Data, when the first pulse signal is input by the Data signal input terminal Data, the first lighting control signal input terminal En-1 inputs the second pulse signal, where the first pulse signal is a low level signal and the second pulse signal is a high level signal, and it is ensured that when the first pulse signal is input by the Data signal input terminal Data, the second transistor T2 is turned off, so that the voltage input by the first level signal input terminal ELVDD cannot be input to the pixel circuit. In addition, the width of the second pulse signal is preferably greater than the width of the first pulse signal, so as to ensure that the first reference voltage does not affect the voltage input by the Data signal input end Data at all, and ensure that the pixel circuit works normally.
Optionally, for the pixel circuit shown in fig. 1 and fig. 3, the operation timing sequence may further include a holding phase t5, referring to fig. 2 and fig. 4, the holding phase t5 is before the light-emitting phase t4, and in the holding phase t5, the signal input by the Data signal input terminal Data jumps from the Data signal voltage to the second reference voltage to prepare for displaying the next frame.
The pixel circuit and the corresponding working timing sequence thereof provided by this embodiment input a first pulse signal through a data signal input end, an input signal of a first light-emitting control signal input end includes two second pulse signals, a latter second pulse signal of the two second pulse signals overlaps with the first pulse signal, and a width of the second pulse signal is greater than a width of the first pulse signal, so that when the first pulse signal is input at the data signal input end, the second transistor is in a cut-off state, and further, the first reference voltage cannot be input to the second plate of the first capacitor C1, which does not affect the input signal at the data signal input end, and ensures that the pixel circuit works normally.
Based on the same inventive concept, the present invention further provides a display panel, and fig. 5 is a schematic structural diagram of a display panel provided in an embodiment of the present invention. As shown in fig. 5, the display panel includes a plurality of pixel circuits provided in the above embodiments, and further includes a data signal driving unit 110, a scan signal driving power source 120, and a light emitting signal driving unit 130. The data signal driving unit 110 is electrically connected to the data signal input terminals of the pixel circuits through a plurality of data lines D1, D2, D3, D4 … …, for inputting data signals to the data signal input terminals; the scan signal driving unit 120 is connected to the first and second scan signal input terminals of the pixel circuit through a plurality of scan lines S1, S2, S3, S4 … …, respectively, for supplying scan signals to the first and second scan signal input terminals; the light emission signal driving unit 130 is connected to the first and second light emission control signal input terminals of the pixel circuit through a plurality of control signal lines E1, E2, E3, E4 … …, for inputting light emission control signals to the first and second light emission control signal input terminals.
The display panel provided by the embodiment reduces the number of transistors and the number of signal lines in the pixel circuit, is beneficial to drawing the layout of the pixel circuit, reduces the area of the pixel circuit and is beneficial to improving the pixel density; and the first capacitor C1 and the second capacitor C2 are arranged in the pixel circuit, so that the adjustment range of the data signal voltage is expanded, gray scale modulation is facilitated, and the display effect is better.
An embodiment of the present invention further provides a driving method of a pixel circuit, and fig. 6 is a flowchart of the driving method of the pixel circuit according to the embodiment of the present invention, where the driving method is used for driving the pixel circuit shown in fig. 1. In this driving method, signals input from the first and second scan signal input terminals Sn and Sn-1 may be provided by the scan signal driving unit 120 of the display panel shown in fig. 5, input signals from the first and second light emission control signal input terminals En-1 and En may be provided by the light emission signal driving unit 130 of the display panel shown in fig. 5, and an input signal from the Data signal input terminal Data may be provided by the Data signal driving unit 110 of the display panel shown in fig. 5. The input of the second scan signal input terminal Sn-1 is a previous frame scan signal of the scan signal input by the first scan signal input terminal Sn, and the light emission control signal input by the first light emission control signal input terminal En-1 is a previous frame light emission control signal of the light emission signal input by the second light emission control signal input terminal En.
The driving method includes:
s110, in the reset phase, a first control signal is input to the first scan signal input terminal Sn and the second emission control signal input terminal En, the first transistor T1 and the third transistor T3 are turned on, and the first electrode potential of the organic light emitting device D1 is written into the control terminal of the driving transistor T0 through the turned-on first transistor T1;
s120, in a write compensation stage, a first control signal is input to a first light-emitting control signal input end En-1, and a second transistor T2 is turned on; a first control signal is input to the first scan signal input terminal Sn, and the first transistor T1 is turned on; the first reference voltage is written into the control terminal of the driving transistor T0 through the turned-on second transistor T2, the driving transistor T0 and the first transistor T1, and when the voltage difference between the control terminal and the first terminal of the driving transistor T0 is equal to the threshold voltage thereof, the driving transistor T0 is turned off; in the reset phase t1 and the write compensation phase t2, a second reference voltage is input to the Data signal input end Data;
s130, in a Data writing stage, a Data signal input end Data input signal jumps to a Data signal voltage from a second reference voltage, and the second reference voltage is transmitted to a first plate of a first capacitor C1; a second control signal is input to the first light emitting control signal input terminal En-1, and the second transistor T2 is turned off;
s140, in a light emitting stage, a first control signal is input to a first light emitting control signal input end En-1, and a second transistor T2 is turned on; the first control signal is input to the second light emission control signal input terminal En, the third transistor T3 is turned on, and the driving transistor T0 drives the organic light emitting element D1 to emit light.
The driving method of the pixel circuit provided by this embodiment, in cooperation with the pixel circuit shown in fig. 1, reduces the number of transistors and the number of signal lines in the pixel circuit, is beneficial to drawing the layout of the pixel circuit, reduces the area of the pixel circuit, and is beneficial to improving the pixel density; and the first capacitor C1 and the second capacitor C2 are arranged in the pixel circuit, so that the adjustment range of the data signal voltage is expanded, gray scale modulation is facilitated, and the display effect is better.
An embodiment of the present invention further provides another driving method for a pixel circuit, and fig. 7 is a flowchart of another driving method for a pixel circuit according to an embodiment of the present invention, where the driving method is used for driving the pixel circuit shown in fig. 3. In this driving method, signals input from the first and second scan signal input terminals Sn and Sn-1 may be provided by the scan signal driving unit 120 of the display panel shown in fig. 5, input signals from the first and second light emission control signal input terminals En-1 and En may be provided by the light emission signal driving unit 130 of the display panel shown in fig. 5, and an input signal from the Data signal input terminal Data may be provided by the Data signal driving unit 110 of the display panel shown in fig. 5. The input of the second scan signal input terminal Sn-1 is a previous frame scan signal of the scan signal input by the first scan signal input terminal Sn, and the light emission control signal input by the first light emission control signal input terminal En-1 is a previous frame light emission control signal of the light emission signal input by the second light emission control signal input terminal En.
The driving method includes:
s210, in a first reset stage, a first control signal is input to the second scanning signal input end Sn-1, the fourth transistor T4 is conducted, and a reset signal input by the reset signal input end is transmitted to the control end of the driving transistor T0 through the conducted fourth transistor T4;
s220, in the second reset stage, the first control signal is input to the first scan signal input terminal Sn, the first transistor T1 is turned on, and the reset signal input from the reset signal input terminal is transmitted to the second terminal of the driving transistor T0 through the turned-on fourth transistor T4 and the first transistor T1;
s230, in a write compensation stage, a first control signal is input to a first light-emitting control signal input end En-1, and a second transistor T2 is turned on; a first control signal is input to the first scan signal input terminal Sn, and the first transistor T1 is turned on; the first reference voltage is written into the control terminal of the driving transistor T0 through the turned-on second transistor T2, the driving transistor T0 and the first transistor T1, and when the voltage difference between the control terminal and the first terminal of the driving transistor T0 is equal to the threshold voltage thereof, the driving transistor T0 is turned off; a first reset phase t11, a second reset phase t12 and a writing compensation phase t2, wherein a second reference voltage is input into a Data signal input end Data;
s240, in a Data writing stage, a Data signal input end Data input signal jumps to a Data signal voltage from a second reference voltage, and the second reference voltage is transmitted to a first plate of a first capacitor C1; a second control signal is input to the first light emitting control signal input terminal En-1, and the second transistor T2 is turned off;
s250, in a light emitting stage, a first control signal is input to a first light emitting control signal input end En-1, and a second transistor T2 is turned on; the first control signal is input to the second light emission control signal input terminal En, the third transistor T3 is turned on, and the driving transistor T0 drives the organic light emitting element D1 to emit light.
The embodiment provides a driving method of a pixel circuit, and further provides a resetting method of the driving transistor T0 on the basis of improving the pixel density and expanding the voltage regulation range of the data signal, so that the resetting of the driving transistor T0 is more accurate.
Optionally, for the driving method of any pixel circuit provided in the foregoing embodiment, before the light-emitting period t4, the method further includes
And in the holding stage, the signal input by the Data signal input end Data jumps to a second reference voltage from the Data signal voltage. Optionally, before the signal input at the Data signal input terminal Data jumps to the second reference voltage from the Data signal voltage, the second control signal is input at the first scan signal input terminal Sn, and the first transistor T1 is turned off. Specifically, before the signal input by the Data signal input terminal Data jumps from the Data signal voltage to the second reference voltage, the first scan signal input terminal Sn inputs the second control signal, so that the first transistor T1 is turned off, the first reference voltage cannot be input to the second plate of the first capacitor C1, and thus the first reference voltage is not affected by the input voltage of the Data signal input terminal Data, and the normal operation of the pixel circuit is ensured. It should be noted that, when the signal input from the Data signal input terminal Data jumps from the Data signal voltage to the second reference voltage, the second control signal may be input to the first scan signal input terminal Sn to turn off the first transistor T1.
Optionally, the first control signal is a low level signal, and the second control signal is a high level signal. Specifically, when the first transistor T1, the second transistor T2, the third transistor T3, the fourth transistor T4, and the driving transistor T0 are P-type transistors, the first control signal is a low level signal, and the second control signal is a high level signal.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A pixel circuit includes a first transistor, a second transistor, a third transistor, a driving transistor, a first capacitor, a second capacitor, and an organic light emitting element;
the control end of the first transistor is electrically connected with the first scanning signal input end of the pixel circuit, the first end of the first transistor is electrically connected with the control end of the driving transistor, and the second end of the first transistor is electrically connected with the second end of the driving transistor;
a first end of the second transistor is electrically connected with a first level signal input end of the pixel circuit, a second end of the second transistor is electrically connected with a first end of the driving transistor, and a control end of the second transistor is electrically connected with a first light-emitting control signal input end of the pixel circuit;
a first terminal of the third transistor is electrically connected to a second terminal of the driving transistor, a second terminal of the third transistor is electrically connected to a first pole of the organic light emitting element, a control terminal of the third transistor is electrically connected to a second light emission control signal input terminal of the pixel circuit, and a second pole of the light emitting element is connected to a second level signal input terminal of the pixel circuit;
the first electrode of the second capacitor is used for inputting a first reference voltage, and the second electrode of the second capacitor is electrically connected with the control end of the driving transistor;
a first pole of the first capacitor is electrically connected with a data signal input end of the pixel circuit, and a second pole of the first capacitor is electrically connected with a second end of the first transistor;
in a frame of display, the signal input by the data signal input end comprises a first pulse signal;
in one frame of display, the input signal of the first lighting control signal input end comprises two second pulse signals, the latter one of the two second pulse signals is overlapped with the first pulse signal, and the width of the second pulse signal is larger than the width of the first pulse signal.
2. The pixel circuit according to claim 1, wherein a first pole of the second capacitor is electrically connected to the first level signal input terminal.
3. The pixel circuit according to claim 1, further comprising a fourth transistor, wherein a control terminal of the fourth transistor is electrically connected to the second scan signal input terminal of the pixel circuit, a first terminal of the fourth transistor is electrically connected to the reset signal input terminal of the pixel circuit, and a second terminal of the fourth transistor is electrically connected to the control terminal of the driving transistor.
4. The pixel circuit according to claim 3, wherein the first transistor, the second transistor, the third transistor, the fourth transistor, and the driving transistor are P-type transistors.
5. A display panel comprising the pixel circuit according to any one of claims 1 to 4.
6. A method of driving the pixel circuit according to claim 1, comprising:
a reset stage in which a first control signal is input to the first scan signal input terminal and the second emission control signal input terminal, the first transistor and the third transistor are turned on, and a first electrode potential of the organic light emitting element is written into the control terminal of the driving transistor through the turned-on first transistor;
a write compensation stage, in which a first control signal is input to the first light-emitting control signal input end, and the second transistor is turned on; inputting a first control signal to the first scanning signal input end, wherein the first transistor is conducted; the first reference voltage is written into the control end of the driving transistor through the second transistor, the driving transistor and the first transistor which are turned on, and when the voltage difference between the control end and the first end of the driving transistor is equal to the threshold voltage of the driving transistor, the driving transistor is turned off; in the reset phase and the write compensation phase, a second reference voltage is input to the data signal input end;
in a data writing stage, an input signal of the data signal input end jumps from the second reference voltage to a data signal voltage, and the second reference voltage is transmitted to a first polar plate of the first capacitor; inputting a second control signal to the first light-emitting control signal input end, and turning off the second transistor;
a light emitting stage, wherein a first control signal is input to the first light emitting control signal input end, and the second transistor is conducted; and a first control signal is input to the second light-emitting control signal input end, the third transistor is conducted, and the driving transistor drives the organic light-emitting element to emit light.
7. A method of driving the pixel circuit according to claim 3, comprising:
in the first reset stage, a first control signal is input to the second scan signal input end, the fourth transistor is turned on, and a reset signal input by the reset signal input end is transmitted to the control end of the driving transistor through the turned-on fourth transistor;
in the second reset stage, a first control signal is input to the first scanning signal input end, the first transistor is turned on, and a reset signal input by the reset signal input end is transmitted to the second end of the driving transistor through the turned-on fourth transistor and the turned-on first transistor;
a write compensation stage, in which a first control signal is input to the first light-emitting control signal input end, and the second transistor is turned on; inputting a first control signal to the first scanning signal input end, wherein the first transistor is conducted; writing a first reference voltage into a control end of the driving transistor through the turned-on second transistor, the driving transistor and the first transistor, and turning off the driving transistor when a voltage difference between the control end and the first end of the driving transistor is equal to a threshold voltage of the driving transistor; in the first reset phase, the second reset phase and the write compensation phase, a second reference voltage is input to the data signal input end;
in a data writing stage, an input signal of the data signal input end jumps from the second reference voltage to a data signal voltage, and the second reference voltage is transmitted to a first polar plate of the first capacitor; inputting a second control signal to the first light-emitting control signal input end, and turning off the second transistor;
a light emitting stage, wherein a first control signal is input to the first light emitting control signal input end, and the second transistor is conducted; and a first control signal is input to the second light-emitting control signal input end, the third transistor is conducted, and the driving transistor drives the organic light-emitting element to emit light.
8. The method for driving the pixel circuit according to claim 6 or 7, further comprising a holding phase before the light-emitting phase, wherein the signal inputted to the data signal input terminal jumps from the data signal voltage to the second reference voltage in the holding phase.
9. The method for driving the pixel circuit according to claim 8, wherein a second control signal is input to the first scan signal input terminal and the first transistor is turned off before a signal input to the data signal input terminal transitions from the data signal voltage to the second reference voltage.
10. The method for driving the pixel circuit according to claim 6 or 7, wherein the first control signal is a low level signal, and the second control signal is a high level signal.
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| CN111754941B (en) * | 2020-07-29 | 2022-04-15 | 京东方科技集团股份有限公司 | Pixel circuit, driving method thereof, display substrate and display device |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107154239A (en) * | 2017-06-30 | 2017-09-12 | 武汉天马微电子有限公司 | A kind of image element circuit, driving method, organic electroluminescence display panel and display device |
| CN107331351A (en) * | 2017-08-24 | 2017-11-07 | 京东方科技集团股份有限公司 | A kind of pixel compensation circuit, its driving method, display panel and display device |
| CN108074529A (en) * | 2016-11-14 | 2018-05-25 | 创王光电股份有限公司 | Pixel circuit in electroluminescent display |
| CN108231007A (en) * | 2016-12-13 | 2018-06-29 | 三星显示有限公司 | Display device and its driving method |
| CN108399893A (en) * | 2018-01-31 | 2018-08-14 | 昆山国显光电有限公司 | A kind of pixel compensation circuit, pixel compensation method and display device |
| CN108417182A (en) * | 2017-02-09 | 2018-08-17 | 三星显示有限公司 | Pixel and display equipment with pixel |
-
2018
- 2018-08-27 CN CN201810981008.9A patent/CN110867160B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108074529A (en) * | 2016-11-14 | 2018-05-25 | 创王光电股份有限公司 | Pixel circuit in electroluminescent display |
| CN108231007A (en) * | 2016-12-13 | 2018-06-29 | 三星显示有限公司 | Display device and its driving method |
| CN108417182A (en) * | 2017-02-09 | 2018-08-17 | 三星显示有限公司 | Pixel and display equipment with pixel |
| CN107154239A (en) * | 2017-06-30 | 2017-09-12 | 武汉天马微电子有限公司 | A kind of image element circuit, driving method, organic electroluminescence display panel and display device |
| CN107331351A (en) * | 2017-08-24 | 2017-11-07 | 京东方科技集团股份有限公司 | A kind of pixel compensation circuit, its driving method, display panel and display device |
| CN108399893A (en) * | 2018-01-31 | 2018-08-14 | 昆山国显光电有限公司 | A kind of pixel compensation circuit, pixel compensation method and display device |
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