CN108010487A - A kind of image element circuit and its driving method, display device - Google Patents
A kind of image element circuit and its driving method, display device Download PDFInfo
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- CN108010487A CN108010487A CN201610965090.7A CN201610965090A CN108010487A CN 108010487 A CN108010487 A CN 108010487A CN 201610965090 A CN201610965090 A CN 201610965090A CN 108010487 A CN108010487 A CN 108010487A
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- film transistor
- tft
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3233—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the current through the light-emitting element
Abstract
The invention discloses a kind of image element circuit and its driving method, display device, including：First film transistor, the second thin film transistor (TFT), the 3rd thin film transistor (TFT), the 4th thin film transistor (TFT), the 5th thin film transistor (TFT), storage capacitance and light emitting diode.The grid of the thin film transistor (TFT) as driving element is initialized using supply voltage.In lumination of light emitting diode, the electric current for flowing through light emitting diode is determined by the data voltage in image element circuit and the operating voltage of light emitting diode, it is unrelated with the threshold voltage of the thin film transistor (TFT), therefore, can be to avoid the difference for the electric current that light emitting diode is flowed through caused by the difference due to the threshold voltage of thin film transistor (TFT), so that the problem of display device brightness irregularities.
Description
Technical field
The present invention relates to display technology field, more particularly to a kind of image element circuit and its driving method, display device.
Background technology
In display technology field, a display device can include multiple pixel units, each pixel unit can be right
An image element circuit is answered, two thin film transistor (TFT) TFT (English spellings can be included in an image element circuit：Thin Film
) and a capacitance C Transistor.As shown in Figure 1, be the circuit structure diagram of existing image element circuit, it will be seen from figure 1 that
Two thin film field effect transistor T1 and T2, a capacitance Cs and an Organic Light Emitting Diode OLED are included in image element circuit
(English spelling：Organic Light Emitting Diode)., can be every by controlling during the display of display device
OLED in one image element circuit shines so that display device shines.
Thin film transistor (TFT) T1 in Fig. 1 can be used as switch, and thin film transistor (TFT) T2 can be driving element, and Cs is storage electricity
Hold.The operation principle of image element circuit is in Fig. 1：First, thin film transistor (TFT) T1 is opened by scanning line voltage Vsacn, and inputted
Data voltage Vdata, at this time, data voltage Vdata can charge capacitance Cs；Secondly, closed by scanning line voltage Vsacn
Thin film transistor (TFT) T1, Vdata voltage keep stablizing, and the electric current that supply voltage Vdd is produced is driven by thin film transistor (TFT) T2 and shone
Diode OLED shines.In this way, each OLED included by controlling in display device shines so that display device shines.
In general, when making TFT, can make to obtain using low temperature polysilicon process, still, in practical applications, by
In low temperature polysilicon process the defects of property, cause the threshold voltage of each TFT different, in this way, in image element circuit, in input electricity
Press it is identical in the case of, the electric current that different threshold voltages can cause to flow through OLED is different so that the brightness that OLED shines is different,
In this way, for whole display device, since the brightness that OLED shines is different, cause the brightness irregularities of display device.
The content of the invention
In view of this, an embodiment of the present invention provides a kind of image element circuit and its driving method, display device, for solving
The problem of brightness irregularities of display device are caused due to the threshold voltage difference of thin film transistor (TFT).
The present invention provides a kind of image element circuit, including：First film transistor, the second thin film transistor (TFT), the 3rd film
Transistor, the 4th thin film transistor (TFT), the 5th thin film transistor (TFT), storage capacitance and light emitting diode, wherein：
The first film transistor drain electrode respectively with the first power supply, one end of the storage capacitance and the described 4th
The drain electrode connection of thin film transistor (TFT)；
The source electrode of the first film transistor is connected with the drain electrode of the 3rd thin film transistor (TFT), and the 3rd film is brilliant
The source electrode of body pipe is connected with the anode of the light emitting diode, and the cathode of the light emitting diode is connected with second source；
The grid of the first film transistor source electrode with the 4th thin film transistor (TFT), the storage capacitance respectively
The grid of the other end and second thin film transistor (TFT) connects, drain electrode and second film of second thin film transistor (TFT)
The grid connection of transistor, the source electrode of second thin film transistor (TFT) is connected with the drain electrode of the 5th thin film transistor (TFT), described
The source electrode of 5th thin film transistor (TFT) is connected with data cable.
Alternatively, first power supply is used to initialize the grid of the first film transistor.
Alternatively, the grid of the 4th thin film transistor (TFT) is connected with the first scan line, the first scanning line traffic control institute
It is in the conduction state to state the 4th thin film transistor (TFT) so that first power supply carries out just the grid of the first film transistor
Beginningization；
The grid of 5th thin film transistor (TFT) is connected with the second scan line, and second scan line is to second film
The threshold voltage of transistor is sampled, and then realizes the compensation to the threshold voltage of the first film transistor；
The grid of 3rd thin film transistor (TFT) is connected with three scan line, and the three scan line control the described 3rd is thin
Film transistor is in the conduction state so that the lumination of light emitting diode.
Alternatively, second scan line samples the threshold voltage of second thin film transistor (TFT), and then realizes
Compensation to the threshold voltage of the first film transistor, including：
5th thin film transistor (TFT) described in the second scanning line traffic control is in the conduction state, the data that the data cable provides
Voltage applies voltage to the grid of the first film transistor so that the grid voltage of the first film transistor is first
Node voltage, the first node voltage are determined by the threshold voltage of the data voltage and second thin film transistor (TFT)；
5th thin film transistor (TFT) described in the second scanning line traffic control is in cut-off state so that the first film crystal
Pipe determines to the electric current between the light emitting diode by the operating voltage and the data voltage of the light emitting diode, with
The threshold voltage of the first film transistor is unrelated.
Alternatively, the first film transistor, second thin film transistor (TFT), the 3rd thin film transistor (TFT), described
4th thin film transistor (TFT) and the 5th thin film transistor (TFT) are N-type TFT.
The present invention provides a kind of driving method of image element circuit, the scan period of the image element circuit is divided into the first rank
Section, second stage and phase III, wherein：
The first stage, the scanning signal that first scan line provides are changed into high level from low level, and described second
The scanning signal that scan line provides keeps low level, and the scanning signal that the three scan line provides is changed into low electricity from high level
Flat, the 4th thin film transistor (TFT) is in the conduction state, second thin film transistor (TFT), the 3rd thin film transistor (TFT) and described
5th thin film transistor (TFT) is in cut-off state, and the voltage that first power supply provides is by the 4th thin film transistor (TFT) to described
The grid of first film transistor is initialized；
The second stage, the scanning signal that first scan line provides are changed into low level from high level, and described second
The scanning signal that scan line provides is changed into high level from low level, and the scanning signal that the three scan line provides keeps low electricity
Flat, the 4th thin film transistor (TFT) is in cut-off state, and the 5th thin film transistor (TFT) is in the conduction state, and the data cable carries
The data voltage of confession applies voltage to the grid of the first film transistor, and samples and obtain second thin film transistor (TFT)
Threshold voltage, the grid voltage of second thin film transistor (TFT) and the grid voltage of first film transistor are by the data voltage
Determined with the threshold voltage of second thin film transistor (TFT)；
The phase III, the scanning signal that first scan line provides keep low level, and second scan line carries
The scanning signal of confession is changed into low level from high level, and the scanning signal that the three scan line provides is changed into high electricity from low level
Flat, the 3rd thin film transistor (TFT) is in the conduction state, and the 5th thin film transistor (TFT) is in cut-off state, and described first is thin
Film transistor controls the lumination of light emitting diode.
Alternatively, in the second stage, when the 5th thin film transistor (TFT) is in the conduction state, the data voltage to
The grid of the first film transistor applies voltage so that the grid voltage of the first film transistor is Vdata+
Vth2, Vdata are the data voltage, and Vth2 is the threshold voltage of second thin film transistor (TFT).
Alternatively, in the phase III, when the 3rd thin film transistor (TFT) is in the conduction state, the first film is brilliant
The grid voltage and source voltage of body pipe are Vdata+Vth2 and VOLED respectively, complete the threshold to the first film transistor
The compensation of threshold voltage, VOLED are the voltage of the LED operation.
Present invention also offers a kind of display device, the display device includes above-mentioned image element circuit.
The present invention has the beneficial effect that：
The embodiment of the present invention, initializes the grid of the thin film transistor (TFT) as driving element using supply voltage,
In lumination of light emitting diode, the electric current of light emitting diode is flowed through by the data voltage and the work of light emitting diode in image element circuit
Make voltage decision, it is unrelated with the threshold voltage of the thin film transistor (TFT), it can thus be avoided the threshold voltage due to thin film transistor (TFT)
Difference caused by flow through light emitting diode electric current difference so that the problem of display device brightness irregularities.
Brief description of the drawings
To describe the technical solutions in the embodiments of the present invention more clearly, make required in being described below to embodiment
Attached drawing is briefly introduced, it should be apparent that, drawings in the following description are only some embodiments of the present invention, for this
For the those of ordinary skill in field, without having to pay creative labor, it can also be obtained according to these attached drawings
His attached drawing.
Fig. 1 is the structure diagram of the image element circuit included in existing display device；
Fig. 2 is a kind of structure diagram of image element circuit provided in an embodiment of the present invention；
Fig. 3 is a kind of sequence diagram of the driving method of image element circuit provided in an embodiment of the present invention.
Embodiment
In order to achieve the object of the present invention, a kind of image element circuit and its driving method are provided in the embodiment of the present invention, is shown
Showing device, the image element circuit include：First film transistor, the second thin film transistor (TFT), the 3rd thin film transistor (TFT), the 4th film
Transistor, the 5th thin film transistor (TFT), storage capacitance and light emitting diode, wherein：The drain electrode difference of the first film transistor
Drain electrode with the first power supply, one end of the storage capacitance and the 4th thin film transistor (TFT) is connected；The first film is brilliant
The source electrode of body pipe is connected with the drain electrode of the 3rd thin film transistor (TFT), the source electrode of the 3rd thin film transistor (TFT) and described luminous two
The anode connection of pole pipe, the cathode of the light emitting diode are connected with second source；The grid of the first film transistor point
The other end of source electrode, the storage capacitance and the grid of second thin film transistor (TFT) not with the 4th thin film transistor (TFT)
Connection, the drain electrode of second thin film transistor (TFT) are connected with the grid of second thin film transistor (TFT), second film crystal
The source electrode of pipe is connected with the drain electrode of the 5th thin film transistor (TFT), and the source electrode of the 5th thin film transistor (TFT) is connected with data cable.
The grid of the thin film transistor (TFT) as driving element is initialized using supply voltage, is sent out in light emitting diode
Light time, the electric current for flowing through light emitting diode determine by the data voltage in image element circuit and the operating voltage of light emitting diode, with
The threshold voltage of the thin film transistor (TFT) is unrelated, it can thus be avoided due to caused by the difference of the threshold voltage of thin film transistor (TFT)
The difference of the electric current of light emitting diode is flowed through, so that the problem of display device brightness irregularities.
The present invention is described in further detail below in conjunction with the accompanying drawings, it is clear that described embodiment is only this hair
Bright part of the embodiment, instead of all the embodiments.Based on the embodiments of the present invention, those of ordinary skill in the art are not having
There is all other embodiment made and obtained under the premise of creative work, belong to the scope of protection of the invention.
Fig. 2 is a kind of structure diagram of image element circuit provided in an embodiment of the present invention.
As shown in Fig. 2, the image element circuit includes：First film transistor M1, the second thin film transistor (TFT) M2, the 3rd film
Transistor M3, the 4th thin film transistor (TFT) M4, the 5th thin film transistor (TFT) M5, storage capacitance C1 and light emitting diode OLED, wherein：
The drain electrode of the first film transistor M1 respectively with one end of the first power supply ELVDD, the storage capacitance C1 with
And the drain electrode connection of the 4th thin film transistor (TFT) M4；
The source electrode of the first film transistor M1 is connected with the drain electrode of the 3rd thin film transistor (TFT) M3, and the described 3rd is thin
The source electrode of film transistor M3 is connected with the anode of the light emitting diode OLED, the cathode and second of the light emitting diode OLED
Power supply ELVSS connections；
The source electrode with the 4th thin film transistor (TFT) M4, the storage are electric respectively for the grid of the first film transistor M1
Hold the grid connection of the other end and the second thin film transistor (TFT) M2 of C1, the drain electrode of the second thin film transistor (TFT) M2 and institute
State the grid connection of the second thin film transistor (TFT) M2, source electrode and the 5th thin film transistor (TFT) M5 of the second thin film transistor (TFT) M2
Drain electrode connection, the source electrode of the 5th thin film transistor (TFT) M5 is connected with data cable DATA.
In the image element circuit, first film transistor M1 is as driving element, the electric current of the first power supply ELVDD
The first film transistor M1 is flowed through, drives the light emitting diode OLED to shine.
Specifically, the first power supply ELVDD is used to initialize the grid of the first film transistor M1.
The image element circuit can receive the first power supply ELVDD that external circuit provides by power supply cabling, described
First power supply ELVDD charges the storage capacitance C1, in charging process, it is possible to achieve to the first film crystal
The initialization of the grid of pipe M1.
In the image element circuit, the grid of the 4th thin film transistor (TFT) M4 is connected with the first scan line S1, and described
Scan line S1 can provide scanning signal, and control the conducting and cut-off of the 4th thin film transistor (TFT) M4, described first
When scan line S1 controls the 4th thin film transistor (TFT) M4 in the conduction state, the voltage pair of the first power supply ELVDD offers
The storage capacitance C1 chargings, in the charging process of C1, the first power supply ELVDD is to the first film transistor M1's
Grid is initialized, and after the storage capacitance C1 charging completes, the grid voltage of the first film transistor M1 is
Vdd, Vdd are the voltage that the first power supply ELVDD is provided.At this time, the first power supply ELVDD is completed to the first film
The initialization of the grid of transistor M1.
The grid of the 5th thin film transistor (TFT) M5 is connected with the second scan line S2, and the second scan line S2 can be provided
Scanning signal, and control the conducting and cut-off of the 5th thin film transistor (TFT) M5, in the second scan line S2 controls described the
In when five thin film transistor (TFT) M5 are in the conduction state, the second scan line S2 can be to the threshold of the second thin film transistor (TFT) M2
Threshold voltage is sampled, and obtains the threshold voltage of the second thin film transistor (TFT) M2, and then is realized brilliant to the first film
The compensation of the threshold voltage of body pipe M1.
Specifically, it is described when the second scan line S2 controls the 5th thin film transistor (TFT) M5 in the conduction state
The data voltage that data cable DATA is provided applies voltage (i.e. to second film to the grid of the first film transistor M1
The grid of transistor M2 applies voltage), and sample and obtain the threshold voltage of the second thin film transistor (TFT) M2, at this time, described the
Two thin film transistor (TFT) M2 are in the conduction state, and the grid voltage of the second thin film transistor (TFT) M2 changes (i.e. described first
The grid voltage of thin film transistor (TFT) M1 changes), the grid voltage of the first film transistor M1 after change is by described
The threshold voltage of data voltage and the second thin film transistor (TFT) M2 determine.
For the ease of distinguishing, the grid voltage of the first film transistor M1 after change can be known as first here
Node voltage.
When the second scan line S2 controls the 5th thin film transistor (TFT) M5 to be in cut-off state, the first film
The grid voltage of transistor M1 will remain unchanged, and drain electrodes of the first power supply ELVDD to the first film transistor applies
Voltage, the electric current of the first power supply ELVDD flow into the light emitting diode OLED by the first film transistor M1.
In embodiments of the present invention, the technique one of the first film transistor M1 and the second thin film transistor (TFT) M2
Cause, size is basically identical, tightly adjacent in laying out pattern, so, the threshold voltage of the first film transistor M1 with it is described
The threshold voltage of second thin film transistor (TFT) M2 is identical, therefore, the first film transistor M1 to the light emitting diode OLED
Between electric current can be determined by the operating voltage and the data voltage of the light emitting diode OLED, it is thin with described first
The threshold voltage of film transistor M1 is unrelated.
The grid of the 3rd thin film transistor (TFT) M3 is connected with three scan line S3, and the three scan line S3 provides scanning
Signal, and the conducting and cut-off of the 3rd thin film transistor (TFT) M3 are controlled, it is thin in three scan line S3 controls the described 3rd
When film transistor M3 is in the conduction state, the electric current that first power supply produces is flowed into by the first film transistor M1
The light emitting diode OLED so that the light emitting diode OLED shines.
Alternatively, in embodiments of the present invention, it may be determined that the first film transistor M1, second film crystal
Pipe M2, the 3rd thin film transistor (TFT) M3, the 4th thin film transistor (TFT) M4 and the 5th thin film transistor (TFT) M5 are thin for N-type
Film transistor.
Fig. 3 is a kind of sequence diagram of the driving method of image element circuit provided in an embodiment of the present invention.The following institute of the method
State.
In embodiments of the present invention, the scan period of the image element circuit includes first stage, second stage and the 3rd rank
Section, wherein：
The first stage, the scanning signal that the first scan line S1 is provided are changed into high level from low level, and described the
The scanning signal that two scan line S2 are provided keeps low level, and the scanning signal that the three scan line S3 is provided is changed into from high level
Low level, the 4th thin film transistor (TFT) M4 is in the conduction state, the second thin film transistor (TFT) M2, the 3rd film crystal
Pipe M3 and the 5th thin film transistor (TFT) M5 is in cut-off state, and the voltage that the first power supply ELVDD is provided passes through described the
Four thin film transistor (TFT) M4 initialize the grid of the first film transistor M1；
The second stage, the scanning signal that the first scan line S1 is provided are changed into low level from high level, and described the
The scanning signal that two scan line S2 are provided is changed into high level from low level, and the scanning signal that the three scan line S3 is provided is kept
Low level, the 4th thin film transistor (TFT) M4 are in cut-off state, and the 5th thin film transistor (TFT) M5 is in the conduction state, described
The data voltage that data cable DATA is provided applies voltage to the grid of the first film transistor M1, and samples and obtain described the
The threshold voltage of two thin film transistor (TFT) M2, the grid voltage of the second thin film transistor (TFT) M2 and the grid of first film transistor M1
Pole tension is determined by the threshold voltage of the data voltage and the second thin film transistor (TFT) M2；
The phase III, the scanning signal that the first scan line S1 is provided keep low level, second scan line
The scanning signal that S2 is provided is changed into low level from high level, and the scanning signal that the three scan line S3 is provided is changed into from low level
High level, the 3rd thin film transistor (TFT) M3 is in the conduction state, and the 5th thin film transistor (TFT) M5 is in cut-off state, institute
Stating first film transistor M1 controls the light emitting diode OLED to shine.
In figure 3, the first stage is the t1 stages, and the second stage is the t2 stages, and the phase III is t3 ranks
Section.
It should be noted that in embodiments of the present invention, the thin film transistor (TFT) included in the image element circuit can be N-type
Thin film transistor (TFT), for N-type TFT, the electricity of the scanning signal loaded by scan line on the grid of thin film transistor (TFT)
Press for high level when, thin film transistor (TFT) is in the conduction state, the scanning loaded by scan line on the grid of thin film transistor (TFT)
When the voltage of signal is low level, thin film transistor (TFT) is in cut-off state.
In embodiments of the present invention, before the scan period is entered, in the image element circuit, the first scan line S1 is provided
Scanning signal can be low level, the scanning signal that the second scan line S2 is provided can be low level, and three scan line S3 is carried
The scanning signal of confession can be high level, that is to say, that before the scan period is entered, the 4th thin film transistor (TFT) M4 and institute
State the 5th thin film transistor (TFT) M5 and be in cut-off state, the 3rd thin film transistor (TFT) M3 is in the conduction state.
Within the scan period, the scanning signal of the different high and low level provided by the scan line in the image element circuit,
Control the thin film transistor (TFT) included in the image element circuit in the conduction state or cut-off state, and then drive the image element circuit
In light emitting diode, make lumination of light emitting diode.
In embodiments of the present invention, the image element circuit enter the scan period when, i.e., in the first stage when, can be right
The grid for the first film transistor M1 that the image element circuit includes is initialized.
Specifically, as shown in figure 3, in the first stage, the scanning signal that the first scan line S1 is provided is changed into high from low level
Level, the scanning signal that the second scan line S2 is provided keep low level, and the scanning signal that three scan line S3 is provided is by high level
It is changed into low level.
In this way, it is high level in the voltage that the grid of the 4th thin film transistor (TFT) M4 loads, the 4th film is brilliant in the first stage
Body pipe M4 is in the conduction state, is low level in the voltage that the grid of the 5th thin film transistor (TFT) M5 loads, the 5th thin film transistor (TFT)
M5 is in cut-off state, is low level in the voltage that the grid of the 3rd thin film transistor (TFT) M3 loads, at the 3rd thin film transistor (TFT) M3
In cut-off state, second thin film transistor (TFT) is in cut-off state.
At this time, since the 4th thin film transistor (TFT) M4 is in the conduction state, then, the first power supply ELVDD is deposited to described
Storing up electricity holds C1 and charges, and during charging, the first power supply ELVDD can be to the first film transistor M1's
Grid is initialized, and after charging, the first power supply ELVDD completes the grid to the first film transistor M1
Initialization, at this time, the grid voltage of the first film transistor M1 is Vdd, and Vdd provides for the first power supply ELVDD
Voltage.
Terminate in the first stage after completing the initialization to the grid voltage of the first film transistor M1, the pixel
Circuit enters second stage.
Specifically, as shown in figure 3, in second stage, the scanning signal that the first scan line S1 is provided is changed into low from high level
Level, the scanning signal that the second scan line S2 is provided are changed into high level from low level, what the three scan line S3 was provided
Scanning signal keeps low level.
It is low level in the voltage that the grid of the 4th thin film transistor (TFT) M4 loads, the 4th film is brilliant in this way, in second stage
Body pipe M4 is in cut-off state, is high level in the voltage that the grid of the 5th thin film transistor (TFT) M5 loads, the 5th thin film transistor (TFT)
M5 is in the conduction state, is low level in the voltage that the grid of the 3rd thin film transistor (TFT) M3 loads, at the 3rd thin film transistor (TFT) M3
In cut-off state.
At this time, since the 5th thin film transistor (TFT) M5 is in the conduction state, external chip passes through the data cable DATA
To the image element circuit input data voltage, the data voltage is by the 5th thin film transistor (TFT) M5 to the first film
The grid of transistor M1 applies voltage, and the threshold voltage of the second thin film transistor (TFT) M2 is sampled, at this time, described the
The grid voltage of one thin film transistor (TFT) M1 will change.
At the end of second stage, grid voltage (i.e. described second thin film transistor (TFT) of the first film transistor M1
The grid voltage of M2) Vdata+Vth2 is changed into from voltage Vdd, Vdata2 is the data voltage, and Vth2 is second film
The threshold voltage of transistor M2.
After second stage, the image element circuit enters the phase III.
Specifically, as shown in figure 3, in the phase III, the scanning signal holding low level of the first scan line S1 offers, second
The scanning signal that scan line S2 is provided is changed into low level from high level, and the scanning signal low level that three scan line S3 is provided becomes
For high level.
It is low level in the grid voltage of the 4th thin film transistor (TFT) M4 in this way, in the phase III, the 4th thin film transistor (TFT) M4
It is low level in the grid voltage of the 5th thin film transistor (TFT) M5, the 5th thin film transistor (TFT) M5 is in cut-off shape in cut-off state
State, is high level in the grid voltage of the 3rd thin film transistor (TFT) M3, the 3rd thin film transistor (TFT) M3 is in the conduction state.
Alternatively, it is in the conduction state in phase III, the second thin film transistor (TFT) M2.
At this time, when the 3rd thin film transistor (TFT) M3 is in the conduction state, the first power supply ELVDD is to described first
The drain electrode of thin film transistor (TFT) M1 applies voltage, the electric current of the first power supply ELVDD by the first film transistor M1 with
And the 3rd thin film transistor (TFT) M3, flow into the light emitting diode OLED so that the light emitting diode OLED shines.
Since when entering the phase III, the grid voltage of the first film transistor M1 is Vdata+Vth2, due to
The threshold voltage of the first film transistor M1 is identical with the threshold voltage of the second thin film transistor (TFT) M2, therefore, flows through
The electric current of the light emitting diode OLED is unrelated with the threshold voltage of the first film transistor T1, and at this time, described first is thin
The source voltage of film transistor M1 is the operating voltage of the light emitting diode OLED.
When the light emitting diode OLED shines, flowing through the electric current of the light emitting diode OLED is：
Ion=1/2 μ Cox·W/L·(Vdata-VOLED)2, wherein, the electronics that μ is first film transistor M1 moves
Shifting rate, CoxFor the unit-area capacitance of first film transistor M1, W/L is the aspect ratio of first film transistor M1, and VOLED is
The operating voltage of the light emitting diode OLED.
As can be seen that flow through the electric current of the light emitting diode OLED and the threshold voltage of the first film transistor M1
It is unrelated, so can to avoid due to threshold voltage it is inconsistent caused by display device brightness irregularities the problem of.
Technical solution provided in an embodiment of the present invention, the grid using supply voltage to the thin film transistor (TFT) as driving element
Pole is initialized, in lumination of light emitting diode, flow through the electric current of light emitting diode by the data voltage in image element circuit and
The operating voltage of light emitting diode determines, unrelated with the threshold voltage of the thin film transistor (TFT), it can thus be avoided since film is brilliant
The difference of the electric current of light emitting diode is flowed through caused by the difference of the threshold voltage of body pipe, so that display device brightness is not
The problem of uniform.
In addition, the embodiment of the present invention additionally provides a kind of display device, includes the image element circuit of above-mentioned record.
It will be understood by those skilled in the art that although preferred embodiments of the present invention have been described, but skill in the art
Art personnel once know basic creative concept, then other change and modification can be made to these embodiments.It is so appended
Claim is intended to be construed to include preferred embodiment and falls into all change and modification of the scope of the invention.
Obviously, various changes and modifications can be made to the invention without departing from model of the invention by those skilled in the art
Enclose.In this way, if these modifications and changes of the present invention belongs within the scope of the claims in the present invention and its equivalent technologies, then
The present invention is also intended to comprising including these modification and variations.
Claims (9)
- A kind of 1. image element circuit, it is characterised in that including：First film transistor, the second thin film transistor (TFT), the 3rd film crystal Pipe, the 4th thin film transistor (TFT), the 5th thin film transistor (TFT), storage capacitance and light emitting diode, wherein：The first film transistor drain electrode respectively with the first power supply, one end of the storage capacitance and the 4th film The drain electrode connection of transistor；The source electrode of the first film transistor is connected with the drain electrode of the 3rd thin film transistor (TFT), the 3rd thin film transistor (TFT) Source electrode be connected with the anode of the light emitting diode, the cathode of the light emitting diode is connected with second source；The grid of the first film transistor respectively the source electrode with the 4th thin film transistor (TFT), the storage capacitance it is another The connection of the grid of end and second thin film transistor (TFT), the drain electrode of second thin film transistor (TFT) and second film crystal The grid connection of pipe, the source electrode of second thin film transistor (TFT) are connected with the drain electrode of the 5th thin film transistor (TFT), and the described 5th The source electrode of thin film transistor (TFT) is connected with data cable.
- 2. image element circuit as claimed in claim 1, it is characterised in thatFirst power supply is used to initialize the grid of the first film transistor.
- 3. image element circuit as claimed in claim 1, it is characterised in thatThe grid of 4th thin film transistor (TFT) is connected with the first scan line, and the 4th film described in the first scanning line traffic control is brilliant Body pipe is in the conduction state so that first power supply initializes the grid of the first film transistor；The grid of 5th thin film transistor (TFT) is connected with the second scan line, and second scan line is to second film crystal The threshold voltage of pipe is sampled, and then realizes the compensation to the threshold voltage of the first film transistor；The grid of 3rd thin film transistor (TFT) is connected with three scan line, and the three scan line controls the 3rd film brilliant Body pipe is in the conduction state so that the lumination of light emitting diode.
- 4. image element circuit as claimed in claim 3, it is characterised in that second scan line is to second thin film transistor (TFT) Threshold voltage sampled, and then realize the compensation to the threshold voltage of the first film transistor, including：5th thin film transistor (TFT) described in the second scanning line traffic control is in the conduction state, the data voltage that the data cable provides Apply voltage to the grid of the first film transistor so that the grid voltage of the first film transistor is first node Voltage, the first node voltage are determined by the threshold voltage of the data voltage and second thin film transistor (TFT)；5th thin film transistor (TFT) described in the second scanning line traffic control is in cut-off state so that the first film transistor is extremely Electric current between the light emitting diode determines by the operating voltage and the data voltage of the light emitting diode, and described The threshold voltage of first film transistor is unrelated.
- 5. image element circuit as claimed in claim 1, it is characterised in that the first film transistor, second film are brilliant Body pipe, the 3rd thin film transistor (TFT), the 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) are N-type film crystal Pipe.
- It is 6. a kind of such as the driving method of claim 1 to 5 any one of them image element circuit, it is characterised in that the scan period point For first stage, second stage and phase III, wherein：The first stage, the scanning signal that first scan line provides are changed into high level, second scanning from low level The scanning signal that line provides keeps low level, and the scanning signal that the three scan line provides is changed into low level from high level, institute It is in the conduction state to state the 4th thin film transistor (TFT), second thin film transistor (TFT), the 3rd thin film transistor (TFT) and the described 5th Thin film transistor (TFT) is in cut-off state, and the voltage that first power supply provides is by the 4th thin film transistor (TFT) to described first The grid of thin film transistor (TFT) is initialized；The second stage, the scanning signal that first scan line provides are changed into low level, second scanning from high level The scanning signal that line provides is changed into high level from low level, and the scanning signal that the three scan line provides keeps low level, institute State the 4th thin film transistor (TFT) and be in cut-off state, the 5th thin film transistor (TFT) is in the conduction state, what the data cable provided Data voltage applies voltage to the grid of the first film transistor, and samples and obtain the threshold value of second thin film transistor (TFT) Voltage, the grid voltage of second thin film transistor (TFT) and the grid voltage of first film transistor are by the data voltage and institute The threshold voltage for stating the second thin film transistor (TFT) determines；The phase III, the scanning signal that first scan line provides keep low level, what second scan line provided Scanning signal becomes low level by high level, and the scanning signal that the three scan line provides becomes high level by low level, institute It is in the conduction state to state the 3rd thin film transistor (TFT), the 5th thin film transistor (TFT) is in cut-off state, the first film crystal Lumination of light emitting diode described in management and control system.
- 7. the driving method of image element circuit as claimed in claim 6, it is characterised in that in the second stage, the described 5th When thin film transistor (TFT) is in the conduction state, the data voltage applies voltage to the grid of the first film transistor so that The grid voltage of the first film transistor is Vdata+Vth2, and Vdata is the data voltage, and Vth2 is thin for described second The threshold voltage of film transistor.
- 8. the driving method of image element circuit as claimed in claim 6, it is characterised in that in the phase III, the described 3rd When thin film transistor (TFT) is in the conduction state, the grid voltage and source voltage of the first film transistor are Vdata+ respectively Vth2 and VOLED, completes the compensation of the threshold voltage to the first film transistor, and VOLED is the light-emitting diodes plumber The voltage of work.
- A kind of 9. display device, it is characterised in that including：Such as claim 1 to 5 any one of them image element circuit.
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| CN201610965090.7A CN108010487A (en) | 2016-10-31 | 2016-10-31 | A kind of image element circuit and its driving method, display device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1975846A (en) * | 2005-12-02 | 2007-06-06 | 三星Sdi株式会社 | Organic light emitting display device and driving method thereof |
| CN102290027A (en) * | 2010-06-21 | 2011-12-21 | 北京大学深圳研究生院 | Pixel circuit and display device |
| CN104078007A (en) * | 2014-07-01 | 2014-10-01 | 何东阳 | Active light-emitting display device pixel circuit |
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2016
- 2016-10-31 CN CN201610965090.7A patent/CN108010487A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1975846A (en) * | 2005-12-02 | 2007-06-06 | 三星Sdi株式会社 | Organic light emitting display device and driving method thereof |
| CN102290027A (en) * | 2010-06-21 | 2011-12-21 | 北京大学深圳研究生院 | Pixel circuit and display device |
| CN104078007A (en) * | 2014-07-01 | 2014-10-01 | 何东阳 | Active light-emitting display device pixel circuit |
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