CN109036289A - Pixel circuit, its driving method and display device - Google Patents
Pixel circuit, its driving method and display device Download PDFInfo
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- CN109036289A CN109036289A CN201811140371.4A CN201811140371A CN109036289A CN 109036289 A CN109036289 A CN 109036289A CN 201811140371 A CN201811140371 A CN 201811140371A CN 109036289 A CN109036289 A CN 109036289A
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3258—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the voltage across the light-emitting element
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Abstract
The present invention relates to a kind of pixel circuit, its driving method and display device, which includes: transistor T1, transistor T2, transistor T3, transistor T4, transistor T5, transistor T6, transistor T7, capacitor C1 and Organic Light Emitting Diode OLED.In initial phase, the first reference voltage Vref 1 is added in the anode of Organic Light Emitting Diode OLED through transistor T7, realizes the initialization of the anode of Organic Light Emitting Diode OLED, the control terminal of 2 initialization transistor T1 of the second reference voltage Vref.During light emitting phase, transistor T5 is connected by LED control signal, the current potential of the first pole of transistor T1 becomes the first supply voltage VDD from data voltage Vdata, the current potential of the control terminal of transistor T1 is from Vdata- | Vth | become Vdata- | and Vth |+η (VDD-Vdata), to flow through coefficient (η -1) in the current formula of Organic Light Emitting Diode OLED2, so that solving grayscale is not easy the technical issues of being unfolded.
Description
Technical field
The present invention relates to OLED pixel drive areas, fill more particularly to a kind of pixel circuit, its driving method and display
It sets.
Background technique
Organic light emitting display be a kind of application Organic Light Emitting Diode (Organic Light-Emitting Diode,
Abbreviation OLED) display as luminescent device, compare Thin Film Transistor-LCD (Thin Film Transistor-
Liquid Crystal Display, abbreviation TFT-LCD), it is thin etc. excellent with high contrast, wide viewing angle, low-power consumption, volume
Point.The brightness of OLED is big by the electric current of driving thin film transistor (TFT) (Thin Film Transistor, abbreviation TFT) circuit generation
Small decision.
Existing active matrix organic light-emitting diode (Active-Matrix Organic Light Emitting
Diode, abbreviation AMOLED) driving method be by pixel circuit output data voltage, data voltage writes direct pixel circuit,
To control the brightness of pixel.
Inventors have found that there are adjacent grayscale to be not easy with the raising of luminescent device performance and display panel resolution ratio
The technical issues of expansion.
Summary of the invention
Based on this, it is necessary to be not easy the technical issues of being unfolded for grayscale adjacent in traditional technology, provide a kind of pixel
Circuit, its driving method and display device.
A kind of pixel circuit, comprising: transistor T1, transistor T2, transistor T3, transistor T4, transistor T5, transistor
T6, transistor T7, transistor T8, capacitor C1 and Organic Light Emitting Diode OLED；The control terminal of the transistor T4 is for inputting
First scanning signal, the first pole of the transistor T4 connect the control terminal of the second pole of the transistor T3, the transistor T1
And the one end the capacitor C1, the second pole of another termination of capacitor C1 transistor T2, the transistor T8 second
First pole of pole, the second pole of the transistor T5 and the transistor T1；The control terminal of the transistor T5 is for inputting hair
Optical control signal, the first pole of the transistor T5 meet the first supply voltage VDD；The second pole of the transistor T4 is used for
The first reference voltage Vref 1 is inputted, and connects the second pole of the transistor T7；The control terminal of the transistor T8 is for inputting the
Scan signal, the first pole of the transistor T8 is for inputting the second reference voltage Vref 2；The control terminal of the transistor T2
For inputting the second scanning signal, the first pole of the transistor T2 is used for input data voltage Vdata；The transistor T3's
Control terminal for input the second scanning signal, the first pole of the transistor T3 connect the transistor T1 the second pole and the crystalline substance
The first pole of body pipe T6；The control terminal of the transistor T6 is for inputting LED control signal, the second pole of the transistor T6
Connect the first pole of the transistor T7；The control terminal of the transistor T7 is for inputting the first scanning signal, the transistor T7
The first pole connect the input terminal of the Organic Light Emitting Diode OLED；The output end of the Organic Light Emitting Diode OLED is for defeated
Enter second source voltage VSS.
The transistor T1, the transistor T2, the transistor T3, the transistor in one of the embodiments,
T4, the transistor T5, the transistor T6, the transistor T7 and the transistor T8 are low-temperature polysilicon film crystal
Any one of pipe, oxide semiconductor thin-film transistor and amorphous silicon film transistor.
The transistor T1, the transistor T2, the transistor T3, the transistor in one of the embodiments,
Transistor T6 described in T4, the transistor T5, the transistor T7 and the transistor T8 are P-type TFT.
First reference voltage Vref 1 is lower than the second source power supply VSS in one of the embodiments,.
A kind of driving method of pixel circuit, the driving method based on pixel circuit described in any of the above-described embodiment,
Include:
Initial phase, first scanning signal are low level signal, second scanning signal and the luminous control
Signal processed is high level signal；First reference voltage Vref 1, for initializing the Organic Light Emitting Diode OLED's
The control terminal of anode and the transistor T1；
Memory phase, first scanning signal and the LED control signal are high level signal, and described second sweeps
Retouching signal is low level signal；The data voltage Vdata, for the capacitor C1 to be written in offset voltage；
Light emitting phase, first scanning signal and second scanning signal are high level signal, the luminous control
Signal processed is low level signal；The first supply voltage VDD, for being supplied to the Organic Light Emitting Diode OLED so that institute
Organic Light Emitting Diode OLED is stated to shine.
In one of the embodiments, in the initial phase, the transistor T4 is led by first scanning signal
Logical, first reference voltage Vref 1 connects one end of the transistor T1 control terminal for initializing the capacitor C1.
In one of the embodiments, in the initial phase, the transistor T8 is led by first scanning signal
Logical, second reference voltage Vref 2 connects one end of second pole transistor T1 for initializing the capacitor C1.
In one of the embodiments, in the memory phase, the transistor T5 is ended by the LED control signal,
The transistor T2 is connected by second scanning signal, and the current potential of the first pole of the transistor T1 is equal to data voltage
Vdata；The current potential of the control terminal of the transistor T1 is equal to Vdata- | Vth |.
In one of the embodiments, in the light emitting phase, the transistor T5 is connected by the LED control signal,
The transistor T4 is ended by first scanning signal, and the transistor T3 is ended by second scanning signal, the crystalline substance
The current potential of the first pole of body pipe T1 is equal to the first supply voltage VDD；
The current potential of the control terminal of the transistor T1 is equal to Vdata- | Vth |+η (VDD-Vdata)；
Wherein, η is other electricity of total capacitance in addition to capacitor C1 at the capacitor C1 and the transistor T1 control terminal
Hold the dividing ratios coefficient that C2 is determined.
A kind of display device, comprising: the pixel circuit as described in above-mentioned any embodiment.
Above-mentioned pixel circuit, its driving method and display device, the pixel circuit include: transistor T1, transistor T2, crystalline substance
Body pipe T3, transistor T4, transistor T5, transistor T6, transistor T7, capacitor C1 and Organic Light Emitting Diode OLED.Initial
Change stage, the first reference voltage Vref 1 are added in the anode of Organic Light Emitting Diode OLED through transistor T7, realize organic light emission two
The initialization of the anode of pole pipe OLED, the second reference voltage Vref 2 are added in the control terminal of transistor T1 through transistor T4, initially
Change the control terminal of transistor T1.During light emitting phase, transistor T5 is connected by LED control signal, the first pole of transistor T1
Current potential the first supply voltage VDD is become from data voltage Vdata, since transistor T3 and transistor T4 is in off state,
The electricity of capacitor C1 remains unchanged, and the current potential of the control terminal of transistor T1 is from Vdata- | Vth | become Vdata- | and Vth |+η
(VDD-Vdata), to flow through coefficient (η -1) in the current formula of Organic Light Emitting Diode OLED2, since η is close to 1, so
The corresponding data voltage Vdata value of adjacent grayscale can have biggish difference, to solve the skill that grayscale is not easy to be unfolded
Art problem.
Detailed description of the invention
Fig. 1 is the circuit diagram of the pixel circuit in the application one embodiment；
Fig. 2 is in the application one embodiment using the circuit diagram of the pixel circuit of P-type TFT；
Fig. 3 is the timing diagram of driving method in the application one embodiment；
Fig. 4 is the structural schematic diagram of display device in another embodiment of the application.
Specific embodiment
In order to make the foregoing objectives, features and advantages of the present invention clearer and more comprehensible, with reference to the accompanying drawing to the present invention
Specific embodiment be described in detail.Many details are explained in the following description in order to fully understand this hair
It is bright.But the invention can be embodied in many other ways as described herein, those skilled in the art can be not
Similar improvement is done in the case where violating intension of the present invention, therefore the present invention is not limited by the specific embodiments disclosed below.
In one embodiment, referring to Figure 1, the application provides a kind of pixel circuit.The pixel circuit includes: transistor
T1, transistor T2, transistor T3, transistor T4, transistor T5, transistor T6, transistor T7, transistor T8, capacitor C1 and have
Machine light emitting diode OLED.Wherein, transistor T1 to transistor T8 includes control terminal, the first pole and the second pole.
Specifically, the control of transistor T4 terminates the first scanning signal end, transmits for inputting through the first scan signal line
The first scanning signal SCAN1.The first pole of transistor T4 connects the control terminal and capacitor of the second pole of transistor T3, transistor T1
The one end C1, the second pole of another termination transistor T2, the second pole of transistor T8, the second pole of transistor T5 and the crystalline substance of capacitor C1
The first pole of body pipe T1.
The control terminal sending and receiving photocontrol end of transistor T5, for inputting the LED control signal transmitted through light emitting control line
The first pole of EM, transistor T5 meet the first supply voltage VDD.
The second pole of transistor T4 connects the second pole of transistor T7 for inputting the first reference voltage Vref 1.
The control of transistor T8 terminates the first scanning signal end, first sweeps for input through the first scan signal line transmits
Signal SCAN1 is retouched, the first pole of transistor T8 is for inputting the second reference voltage Vref 2.
The control of transistor T2 terminates the second scanning signal end, second sweeps for input through the second scan signal line transmits
Signal SCAN2 is retouched, the first pole of transistor T2 is used for input data voltage Vdata.
For the control terminal of transistor T3 for inputting the second scanning signal, the first pole of transistor T3 connects the second of transistor T1
First pole of pole and transistor T6.
The light emitting control end of transistor T6, for inputting the LED control signal EM transmitted through light emitting control line, transistor
The second pole of T6 connects the first pole of transistor T7.
Transistor T7's connects the first scanning signal end, for inputting the first scanning signal transmitted through the first scan signal line
SCAN1, the first pole of transistor T7 connect the input terminal of Organic Light Emitting Diode OLED.
The output of Organic Light Emitting Diode OLED terminates second source, for inputting second source voltage VSS.
Wherein, transistor T2, transistor T3, transistor T4, transistor T5, transistor T6, transistor T7 and transistor T8
It is the switching transistor in pixel circuit.Transistor T1 is the driving transistor in pixel circuit.Capacitor C1 is storage capacitor, even
It is connected between the control terminal of transistor T1 and the first pole of transistor T1.
In the present embodiment, the first scanning signal SCAN1 control transistor T4, transistor T7, transistor T8 cut-off or
Person's conducting, the second scanning signal SCAN2 control the cut-off or conducting of transistor T2, transistor T3.LED control signal EM control
The cut-off or conducting of transistor T5 processed.The cut-off or conducting of LED control signal EM control transistor T6.As transistor T4
When conducting, the first reference voltage Vref 1 flows through the control terminal of transistor T4 initialization transistor T1.When transistor T7 conducting,
First reference voltage Vref 1 flows through the anode of transistor T7 initialization Organic Light Emitting Diode OLED.When transistor T8 conducting,
The first pole plate that second reference voltage Vref 2 initialization capacitor C1 is connect with the second pole transistor T8.When transistor T2 and crystal
When pipe T3 is connected, data voltage Vdata is added in the grid of driving transistor T1 through transistor T2, transistor T1, transistor T3.When
When transistor T5 and transistor T6 is connected, the first supply voltage VDD adds to organic through transistor T5, transistor T1 and transistor T6
Light emitting diode OLED, Organic Light Emitting Diode OLED shine.
In one embodiment, transistor T1, transistor T2, transistor T3, transistor T4, transistor T5 transistor T6,
Transistor T7 and transistor T8 is low-temperature polysilicon film transistor, oxide semiconductor thin-film transistor and amorphous silicon membrane
Any one of transistor.Transistor T1, transistor T2, transistor T3, transistor T4, transistor T5, transistor T6, transistor
T7 and transistor T8 can use P-type TFT, can also use N-type TFT.Using P-type TFT
When as transistor types in driving circuit, to the control terminal input low level signal for the transistor that needs are connected；Using N
When type thin film transistor (TFT) is as transistor types in pixel circuit, to the control terminal input high level for the transistor that needs are connected
Signal.
In one embodiment, refer to Fig. 2, transistor T1 that pixel circuit provided by the present application uses, transistor T2,
Transistor T3, transistor T4, transistor T5 transistor T6, transistor T7 and transistor T8 are P-type TFT.So,
It is understood that control terminal can be the grid of transistor T1 to transistor T8, the first pole can be transistor T1 to crystal
The source electrode of pipe T8, the second pole can be the drain electrode of transistor T1 to transistor T8.
In one embodiment, the first reference voltage Vref 1 is lower than second source voltage VSS.Wherein, in light emitting phase,
First supply voltage VDD adds to Organic Light Emitting Diode OLED, organic light emission two through transistor T5, transistor T1 and transistor T6
Pole pipe OLED shines.Under the action of flowing through the forward current of Organic Light Emitting Diode OLED, hole accumulation and oxygen will cause
Change indium ion movement in indium tin, accelerates the aging of Organic Light Emitting Diode OLED.In initial phase, pass through the first ginseng of setting
Voltage Vref1 is examined lower than second source signal VSS, reverse bias is carried out to Organic Light Emitting Diode OLED, so that compensation shines
Aging caused by stage, and then extend the service life of Organic Light Emitting Diode OLED.
In one embodiment, the application provides the driving method that circuit is moved based on the pixel in any of the above-described embodiment,
The driving method successively includes:
Initial phase, the first scanning signal are low level signal, and the second scanning signal and LED control signal are height
Level signal；First reference voltage Vref 1, the control of anode and transistor T1 for initializing Organic Light Emitting Diode OLED
End；
Memory phase, the first scanning signal and LED control signal are high level signal, and the second scanning signal is low electricity
Ordinary mail number；Data voltage Vdata, for capacitor C1 to be written in offset voltage；
Light emitting phase, the first scanning signal and the second scanning signal are high level signal, and LED control signal is low electricity
Ordinary mail number；First supply voltage VDD, for being supplied to Organic Light Emitting Diode OLED so that Organic Light Emitting Diode OLED is sent out
Light.
Fig. 3 is referred to, Fig. 3 is the corresponding signal timing diagram of the driving method, wherein signal timing diagram includes initialization rank
Section t1, memory phase t2 and light emitting phase t3.Specifically the course of work is as follows:
It is low level signal, transistor T1, transistor T4, transistor in initial phase t1, the first scanning signal SCAN1
T7, transistor T8 conducting, the first reference voltage Vref 1 initialize the control of the anode and transistor T1 of Organic Light Emitting Diode OLED
End processed.The current potential for the second pole plate that capacitor C1 is connect with transistor T1 control terminal is equal to reference voltage Vref 1.Second scanning signal
SCAN2 is high level signal, transistor T2, transistor T3 cut-off.LED control signal EM is high level, transistor T5 and crystal
Pipe T6 cut-off, no driving current flows through Organic Light Emitting Diode OLED, so that it does not shine.
Specifically, in initial phase, transistor T8 is connected by the first scanning signal SCAN1, the second reference voltage Vref 2
The first pole plate that initialization capacitor C1 is connect with the second pole transistor T8.That is capacitor C1 connect with the second pole transistor T8 first
The current potential of pole plate is equal to the second reference voltage Vref 2.Transistor T4 is connected by the first scanning signal SCAN1, the first reference voltage
The second pole plate that Vref1 initialization capacitor C1 is connect with transistor T1 control terminal.That is capacitor C1 is connect with transistor T1 control terminal
The second pole plate current potential be equal to the first reference voltage Vref 1.Capacitor C1 is realized to have initialized in each frame picture point time
Identical state is all had after, to guarantee the accuracy of light emitting control.
It is high level signal in memory phase t2, the first scanning signal SCAN1, LED control signal EM, transistor T4,
Transistor T5, transistor T6, transistor T7 and transistor T8 cut-off, the second scanning signal SCAN2 are low level signal, transistor
T2 and transistor T3 conducting.The current potential of the first pole of transistor T1 is equal to data voltage Vdata, the electricity of the control terminal of transistor T1
Position is equal to Vdata- | Vth |.The control terminal of transistor T1, the first pole of transistor T1 connect the two-plate of capacitor C1 respectively, compensation
Voltage | Vth | write-in capacitor C1.
Specifically, transistor T5 is ended by LED control signal EM, and transistor T2 is connected by the second scanning signal SCAN2,
The current potential of the first pole of transistor T1 is equal to data voltage Vdata.The current potential of the control terminal of transistor T1 is equal to Vdata- | Vth
|。
It is high level signal, crystal in light emitting phase t3, the first scanning signal SCAN1 and the second scanning signal SCAN2
Pipe T4, transistor T7 and transistor T8 cut-off, transistor T2, transistor T3 cut-off.LED control signal EM is low level signal,
Transistor T5, transistor T6 conducting, the first supply voltage VDD have been added to through transistor T5, driving transistor T1 and transistor T6
Machine light emitting diode OLED, so that Organic Light Emitting Diode OLED shines.
Specifically, the first pole plate of capacitor C1 connects the first pole of transistor T1, and the second pole plate of capacitor C1 meets transistor T1
Control terminal.Transistor T5 is connected by LED control signal EM, and the current potential of the first pole plate of capacitor C1 is equal to the first supply voltage
VDD.It is equal to Vdata in the current potential of memory phase t2, the first pole plate of capacitor C1, then the potential change amount of the first pole plate of capacitor C1
Are as follows: VDD-Vdata.Also, other capacitors of the total capacitance at transistor T1 gate node in addition to capacitor C1 are denoted as C2, and other
The partial pressure effect of capacitor C2 further influences the current potential of the second pole plate of capacitor C1, then the current potential of the second pole plate of capacitor C1 is equal to
Vdata-|Vth|+η(VDD-Vdata).Wherein, η is the total capacitance at capacitor C1 and transistor T1 control terminal in addition to capacitor C1
Other capacitors C2 determine dividing ratios coefficient.
In the present embodiment, the current potential of the first pole of transistor T1 becomes the first supply voltage from data voltage Vdata
VDD, since transistor T3 and transistor T4 is in off state, the electricity of capacitor C1 is remained unchanged, the control terminal of transistor T1
Current potential from Vdata- | Vth | become Vdata- | Vth |+η (VDD-Vdata), to flow through Organic Light Emitting Diode OLED's
Coefficient (η -1) in current formula2, since η is close to 1, so the corresponding data voltage Vdata value of adjacent grayscale can have
Biggish difference can accurately control the corresponding data voltage of adjacent grayscale, so that solving grayscale is not easy the technical issues of being unfolded.
It is worked below with reference to the driving method pixels illustrated circuit of the pixel circuit and pixel circuit in above-described embodiment
Journey.Refer to Fig. 2 and Fig. 4, wherein Fig. 4 is the corresponding signal timing diagram of the driving method, and signal timing diagram includes initialization rank
Section t1, memory phase t2 and light emitting phase t3.Specifically the course of work is as follows:
It is low level signal in initial phase t1, the first scanning signal SCAN1, transistor T4 conducting, first with reference to electricity
Press the control terminal of Vref1 initialization transistor T1.Transistor T1 grid connects the second pole plate of capacitor C1, the first reference voltage
The second pole plate of Vref1 initialization capacitor C1.Transistor T7 conducting, the first reference voltage Vref 1 initialize organic light-emitting diodes
The anode of pipe OLED.Transistor T8 conducting, the second reference voltage Vref 2 initialization capacitor C1 are connect with the second pole transistor T8
First pole plate.To which the current potential of the first pole plate of capacitor C1 and transistor T8 drain electrode connection is equal to the second reference voltage Vref 2, electricity
The current potential for holding the second pole plate that C1 is connect with transistor T1 grid is equal to the first reference voltage Vref 1.Capacitor C1 is realized every
Identical state is all had after the completion of initialization in one frame picture point time, to guarantee the accuracy of light emitting control.
It is high level signal in memory phase t2, the first scanning signal SCAN1, LED control signal EM, transistor T4,
Transistor T5, transistor T6, transistor T7 and transistor T8 cut-off.Second scanning signal SCAN2 is low level signal, transistor
T2 and transistor T3 conducting.Data voltage Vdata adds to the source electrode of transistor T1 through transistor T2, faces until transistor T1 is in
Boundary's state, the current potential of the source electrode of transistor T1 are equal to data voltage Vdata, and the current potential of the grid of transistor T1 is equal to Vdata- |
Vth|.Since the source electrode pole of the grid of transistor T1, transistor T1 connects the two-plate of capacitor C1 respectively, thus offset voltage | Vth
| write-in capacitor C1.
At this point, the grid voltage of transistor T2 is Vdata- | Vth |, wherein Vth is the threshold voltage of transistor T1, and
The value of the threshold voltage is negative value, then the grid voltage Vdata+Vth of transistor T1.
It is high level signal, crystal in light emitting phase t3, the first scanning signal SCAN1 and the second scanning signal SCAN2
Pipe T4, transistor T7 and transistor T8 cut-off, transistor T2, transistor T3 cut-off.LED control signal EM is low level letter
Number, transistor T5, transistor T6 conducting, the first supply voltage VDD are added to through transistor T5, driving transistor T1 and transistor T6
Organic Light Emitting Diode OLED, so that Organic Light Emitting Diode OLED shines.
The first pole plate of capacitor C1 connects the source electrode of transistor T1, and the second pole plate of capacitor C1 connects the grid of transistor T1, then
The current potential of the current potential of source electrode of the current potential of the first pole plate of capacitor C1 equal to transistor T1, the second pole plate of capacitor C1 is equal to crystal
The current potential of the grid of pipe T1.Transistor T5 is connected by LED control signal EM, and the current potential of the source electrode of transistor T1 is equal to the first electricity
The current potential of the first pole plate of source voltage VDD, capacitor C1 is equal to the first supply voltage VDD.
Since transistor T3 ends, the electricity of capacitor C1 is remained unchanged, and the voltage difference between capacitor C1 two-plate is also kept
Constant, i.e., the current potential of the first pole plate of capacitor C1 changes with the potential change of the second pole plate of capacitor C1.
It is equal to Vdata in the current potential of memory phase t2, the first pole plate of capacitor C1；
In from memory phase t2 to the time phase of light emitting phase t3, the potential change amount of the first pole plate of capacitor C1 are as follows:
VDD-Vdata。
Also, other capacitors of the total capacitance at transistor T1 gate node in addition to capacitor C1 are denoted as C2, and capacitor C2
Partial pressure effect further influences the current potential of the second pole plate of capacitor C1, then the current potential of the second pole plate of capacitor C1 is equal to Vdata+Vth+ η
(VDD-Vdata)。
Wherein η=C1/ (C1+C2), i.e. η are the dividing ratios coefficient that capacitor C1 and other capacitors C2 is determined.
The second pole plate of capacitor C1 connects the grid of transistor T1, then the current potential of the grid of transistor T1 is equal to Vdata+Vth+
η(VDD-Vdata)。
The source gate pressure drop of transistor T1 are as follows: Vgs=Vg-Vs；
Vgs=Vdata+Vth+ η (VDD-Vdata)-VDD；
Vgs=(1- η) * (VDD-Vdata)+Vth；
Driving current size in transistor T1:
I=K* (Vgs-Vth)2=K* (1- η)2*(VDD-Vdata)2；
Wherein, K=1/2* μ * Cox*W/L.μ is the electron mobility of thin film transistor (TFT), and Cox is thin film transistor (TFT) unit plane
Long-pending gate oxide capacitance, W are the channel widths of thin film transistor (TFT), and L is the channel length of thin film transistor (TFT).
Therefore, the driving current size in available the first transistor T1 are as follows:
I=1/2* μ * Cox*W/L*(1-η)2*(VDD-Vdata)2
It is available from above-mentioned formula, flow through the current formula inlet coefficient (η -1) of Organic Light Emitting Diode OLED2, η
Close to 1, so the corresponding data voltage of adjacent grayscale can have biggish difference, reduces and solve what grayscale was not easy to be unfolded
Technical problem.In addition, the driving current size in transistor T1 is unrelated with the threshold voltage vt h size of transistor T2, thus real
Existing threshold voltage compensation, so that the brightness stability of Organic Light Emitting Diode OLED.
In one embodiment, the application provides a kind of display device, refers to Fig. 4, which includes:
Multiple pixels, for showing image.Each pixel packet appoints the pixel circuit in said one embodiment.
Scanning signal is applied sequentially to pixel by scanner driver 410.
LED control signal is applied to pixel by light emitting control driver 420.
Data voltage is applied to pixel by data driver 430.
Wherein, pixel response scanning signal and receive data voltage, pixel generate have it is corresponding with data voltage predetermined
The light of brightness is to show image.The fluorescent lifetime section of pixel is controlled by LED control signal.Light emitting control driver is in response to first
Beginning control signal is initialised, and generates LED control signal.
Illustratively, Fig. 4 is referred to, scanner driver 410 is arranged by scan signal line S1 to Sn connection matrix form
Multiple pixel PX11 to PXnm, pixel PX11 to PXnm is also connected to LED control signal line E1 to Em, and passes through the control that shines
Signal wire E1 to Em connection light emitting control driver 420 processed.Pixel PX11 to PXnm is also connected to data signal line D1 to Dm, and
Pass through data signal line D1 to Em connection data driver 430.Wherein, LED control signal line E1 to Em is roughly parallel to scanning
Signal wire S1 to Sn.LED control signal line E1 to Em is approximately perpendicular to data signal line D1 to Dm.
Each technical characteristic of embodiment described above can be combined arbitrarily, for simplicity of description, not to above-mentioned reality
It applies all possible combination of each technical characteristic in example to be all described, as long as however, the combination of these technical characteristics is not deposited
In contradiction, all should be considered as described in this specification.
The embodiments described above only express several embodiments of the present invention, and the description thereof is more specific and detailed, but simultaneously
It cannot therefore be construed as limiting the scope of the patent.It should be pointed out that coming for those of ordinary skill in the art
It says, without departing from the inventive concept of the premise, various modifications and improvements can be made, these belong to protection of the invention
Range.Therefore, the scope of protection of the patent of the invention shall be subject to the appended claims.
Claims (10)
1. a kind of pixel circuit characterized by comprising transistor T1, transistor T2, transistor T3, transistor T4, transistor
T5, transistor T6, transistor T7, transistor T8, capacitor C1 and Organic Light Emitting Diode OLED；
For the control terminal of the transistor T4 for inputting the first scanning signal, the first pole of the transistor T4 connects the transistor
The second pole of T3, the control terminal of the transistor T1 and the one end the capacitor C1, another termination crystal of the capacitor C1
The second pole of pipe T2, the second pole of the transistor T8, the second pole of the transistor T5 and the transistor T1 the first pole；
The control terminal of the transistor T5 connects first electricity for inputting LED control signal, the first pole of the transistor T5
Source voltage VDD；
The second pole of the transistor T4 connects the second pole of the transistor T7 for inputting the first reference voltage Vref 1；
The control terminal of the transistor T8 is for inputting the first scanning signal, and the first pole of the transistor T8 is for inputting second
Reference voltage Vref 2；
The control terminal of the transistor T2 is used for input data for inputting the second scanning signal, the first pole of the transistor T2
Voltage Vdata；
For the control terminal of the transistor T3 for inputting the second scanning signal, the first pole of the transistor T3 connects the transistor
First pole of the second pole of T1 and the transistor T6；
For the control terminal of the transistor T6 for inputting LED control signal, the second pole of the transistor T6 connects the transistor
The first pole of T7；
For the control terminal of the transistor T7 for inputting the first scanning signal, the first pole of the transistor T7 connects organic hair
The input terminal of optical diode OLED；
The output end of the Organic Light Emitting Diode OLED is for inputting second source voltage VSS.
2. pixel circuit according to claim 1, which is characterized in that the transistor T1, the transistor T2, the crystalline substance
Body pipe T3, the transistor T4, the transistor T5, the transistor T6, the transistor T7 and the transistor T8 are
Any one of low-temperature polysilicon film transistor, oxide semiconductor thin-film transistor and amorphous silicon film transistor.
3. pixel circuit according to claim 1, which is characterized in that the transistor T1, the transistor T2, the crystalline substance
Body pipe T3, the transistor T4, transistor T6, the transistor T7 and the transistor T8 are P described in the transistor T5
Type thin film transistor (TFT).
4. pixel circuit according to claim 3, which is characterized in that first reference voltage Vref 1 is lower than described the
Two power supply power supply VSS.
5. a kind of display device characterized by comprising such as the described in any item pixel circuits of Claims 1-4.
6. a kind of driving method of pixel circuit, the driving method is based on the described in any item pixel electricity of Claims 1-4
Road characterized by comprising
Initial phase, first scanning signal are low level signal, second scanning signal and light emitting control letter
It number is high level signal；First reference voltage Vref 1, for initializing the anode of the Organic Light Emitting Diode OLED
And the control terminal of the transistor T1；
Memory phase, first scanning signal and the LED control signal are high level signal, the second scanning letter
Number be low level signal；The data voltage Vdata, for the capacitor C1 to be written in offset voltage；
Light emitting phase, first scanning signal and second scanning signal are high level signal, the light emitting control letter
Number be low level signal；The first supply voltage VDD, for being supplied to the Organic Light Emitting Diode OLED so that described have
Machine light emitting diode OLED shines.
7. driving method according to claim 6, which is characterized in that in the initial phase, the transistor T4 by
The first scanning signal conducting, first reference voltage Vref 1 meet the transistor T1 for initializing the capacitor C1
One end of control terminal.
8. driving method according to claim 7, which is characterized in that in the initial phase, the transistor T8 by
The first scanning signal conducting, second reference voltage Vref 2 meet the transistor T1 for initializing the capacitor C1
One end of second pole.
9. driving method according to claim 8, which is characterized in that in the memory phase, the transistor T5 is by institute
LED control signal cut-off is stated, the transistor T2 is connected by second scanning signal, the first pole of the transistor T1
Current potential is equal to data voltage Vdata；
The current potential of the control terminal of the transistor T1 is equal to Vdata- | Vth |.
10. driving method according to claim 9, which is characterized in that in the light emitting phase, the transistor T5 is by institute
LED control signal conducting is stated, the transistor T4 is ended by first scanning signal, and the transistor T3 is by described second
The current potential of scanning signal cut-off, the first pole of the transistor T1 is equal to the first supply voltage VDD；
The current potential of the control terminal of the transistor T1 is equal to Vdata- | Vth |+η (VDD-Vdata)；
Wherein, η is other capacitor C2 of the total capacitance in addition to capacitor C1 at the capacitor C1 and the transistor T1 control terminal
Determining dividing ratios coefficient.
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| CN201811140371.4A CN109036289A (en) | 2018-09-28 | 2018-09-28 | Pixel circuit, its driving method and display device |
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| CN201811140371.4A CN109036289A (en) | 2018-09-28 | 2018-09-28 | Pixel circuit, its driving method and display device |
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| CN109448636A (en) * | 2018-12-29 | 2019-03-08 | 昆山国显光电有限公司 | A kind of driving method of pixel-driving circuit, display device and pixel-driving circuit |
| CN109887466A (en) * | 2019-04-19 | 2019-06-14 | 京东方科技集团股份有限公司 | Pixel-driving circuit and method, display panel |
| CN111402815A (en) * | 2020-03-26 | 2020-07-10 | 昆山国显光电有限公司 | Pixel circuit and display device |
| CN113436579A (en) * | 2021-05-13 | 2021-09-24 | 北京大学深圳研究生院 | Three-dimensional integrated circuit and manufacturing method thereof |
| CN114882837A (en) * | 2022-04-26 | 2022-08-09 | Oppo广东移动通信有限公司 | Pixel driving circuit, control method, display screen and display device |
| WO2024103784A1 (en) * | 2022-11-14 | 2024-05-23 | 武汉华星光电半导体显示技术有限公司 | Pixel circuit and display panel |
| WO2024109348A1 (en) * | 2022-11-25 | 2024-05-30 | 京东方科技集团股份有限公司 | Pixel circuit, driving method, and display device |
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| CN109448636A (en) * | 2018-12-29 | 2019-03-08 | 昆山国显光电有限公司 | A kind of driving method of pixel-driving circuit, display device and pixel-driving circuit |
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| CN113436579A (en) * | 2021-05-13 | 2021-09-24 | 北京大学深圳研究生院 | Three-dimensional integrated circuit and manufacturing method thereof |
| CN113436579B (en) * | 2021-05-13 | 2023-09-22 | 北京大学深圳研究生院 | Three-dimensional integrated circuit and manufacturing method thereof |
| CN114882837A (en) * | 2022-04-26 | 2022-08-09 | Oppo广东移动通信有限公司 | Pixel driving circuit, control method, display screen and display device |
| CN114882837B (en) * | 2022-04-26 | 2023-09-08 | Oppo广东移动通信有限公司 | Pixel driving circuit, control method, display screen and display device |
| WO2024103784A1 (en) * | 2022-11-14 | 2024-05-23 | 武汉华星光电半导体显示技术有限公司 | Pixel circuit and display panel |
| WO2024109348A1 (en) * | 2022-11-25 | 2024-05-30 | 京东方科技集团股份有限公司 | Pixel circuit, driving method, and display device |
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Application publication date: 20181218 |