CN101763780A - Pixel structure and driving method thereof - Google Patents

Pixel structure and driving method thereof Download PDF

Info

Publication number
CN101763780A
CN101763780A CN201010118833A CN201010118833A CN101763780A CN 101763780 A CN101763780 A CN 101763780A CN 201010118833 A CN201010118833 A CN 201010118833A CN 201010118833 A CN201010118833 A CN 201010118833A CN 101763780 A CN101763780 A CN 101763780A
Authority
CN
China
Prior art keywords
driving transistors
gate
transistor
couples
data
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN201010118833A
Other languages
Chinese (zh)
Other versions
CN101763780B (en
Inventor
陈屏先
陈弼先
Original Assignee
CPTF Optronics Co Ltd
Chunghwa Picture Tubes Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by CPTF Optronics Co Ltd, Chunghwa Picture Tubes Ltd filed Critical CPTF Optronics Co Ltd
Priority to CN201010118833A priority Critical patent/CN101763780B/en
Publication of CN101763780A publication Critical patent/CN101763780A/en
Application granted granted Critical
Publication of CN101763780B publication Critical patent/CN101763780B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Abstract

The invention relates to a pixel structure and a driving method thereof. The pixel structure comprises a storage capacitor, a data switch transistor, a disturbance switch transistor, a driving transistor, a display switch transistor and an organic light emitting diode, wherein the data switch transistor can supply data signals to the first end of the storage capacitor according to scanning signals; when the data switch transistor is switched off, the disturbance switch transistor can supply disturbance signals to the first end of the storage capacitor; the first end and the gate electrode of the driving transistor are respectively coupled with constant voltage and the second end of the storage capacitor; and the first end and the second end of the display switch transistor are respectively coupled with the second end of the driving transistor and the positive electrode of the organic light emitting diode. Thus, the service life of the pixel structure can be prolonged.

Description

Image element structure and driving method thereof
Technical field
The invention relates to a kind of image element structure, and particularly relevant for a kind of image element structure and driving method thereof of organic light emitting display.
Background technology
Use Organic Light Emitting Diode (organiclightemittingdiode, OLED) organic light emitting display (organiclightemittingdisplay) is owing to have advantages such as autoluminescence, high brightness, high contrast, wide viewing angle and reaction velocity be fast, and relevant research unit is devoted to the research of its characteristic and driving circuit invariably at present.Though organic light emitting display has above-mentioned advantage, but still some problem needs to be resolved hurrily.
Fig. 1 is the synoptic diagram of known a kind of image element structure.Please refer to Fig. 1, this image element structure uses two transistors (TFT_S, TFT_D), and a storage capacitors Cs, and this image element structure is called as the pixel circuit of 2T1C.The gate of transistor T FT_S couples sweep trace GL, the scanning signal that can provide according to sweep trace GL and conducting.When transistor T FT_S conducting, the data signals of data line DL can be passed to the gate terminal of first end and the transistor T FT_D of storage capacitors Cs, this image element structure is carried out data write.
Transistor T FT_D can be in order to the flow through electric current I o of OLEDD1 of control, by control grid (Gate) voltage, i.e. and the voltage and current at may command TFT_D source/drain (Source/Drain) two ends.Because of transistor T FT_D and OLEDD1 are tandem compound, when applying a fixing voltage Vdd, can see through the change of the source/drain of TFT_D in the TFT_D drain, control electric current I o, and reach the purpose of control GTG by OLEDD1.
What deserves to be mentioned is, transistor T FT_D can be because the factors such as error, long-time operation or environment temperature on the processing procedure, cause critical voltage (ThresholdVoltage) to produce variation, and then make electric current I o produce change, and influence the performance in the picture element brightness by OLEDD1.
In addition, if when picture is in white picture for a long time, transistor T FT_D must continue to provide big electric current to OLEDD1, and transistor T FT_D can be in high current stress (highcurrentstress) for a long time, easily causes the deterioration problem, reduces serviceable life.
Summary of the invention
The invention provides a kind of image element structure, can prolong the life-span of image element structure.
The invention provides a kind of driving method of image element structure, can improve the problem that high current stress causes deterioration.
The present invention proposes a kind of image element structure, comprises storage capacitors, data switch transistor, disturbance switching transistor, driving transistors, display switch transistor AND gate Organic Light Emitting Diode.Storage capacitors has first end and second end.The data switch transistor can provide first end of data signals to storage capacitors according to the scanning signal.When the data switch transistor ended, the disturbance switching transistor can provide first end of disturbing signal to storage capacitors.Driving transistors has first end, second end and gate.First end of driving transistors couples decides voltage.The gate of driving transistors couples second end of storage capacitors.The display switch transistor has first end, second end and gate.Transistorized first end of display switch couples second end of driving transistors.The transistorized gate of display switch receives and shows controlling signal.The anode of Organic Light Emitting Diode couples transistorized second end of display switch.The negative electrode of Organic Light Emitting Diode couples earth terminal.
In one embodiment of this invention, the data switch transistor has first end, second end and gate.Transistorized first end of data switch couples data line and receives data signals.The transistorized gate of data switch couples sweep trace and receives the scanning signal.Transistorized second end of data switch couples first end of storage capacitors.
Hold above-mentionedly, in another embodiment, the disturbance switching transistor has first end, second end and gate.First termination of disturbance switching transistor is received disturbing signal.The gate of disturbance switching transistor couples sweep trace and receives the scanning signal.Second end of disturbance switching transistor couples first end of storage capacitors.Disturbance switching transistor and data switch transistor are made up of P channel transistor and N channel transistor.
In one embodiment of this invention, image element structure more comprises critical voltage electric capacity.Critical voltage electric capacity is coupled between transistorized first end of display switch and the gate.
In one embodiment of this invention, image element structure more comprises shunting driving transistors and diverting switch transistor.The shunting driving transistors has first end, second end and gate.First end of shunting driving transistors couples decides voltage.Second end of shunting driving transistors couples second end of driving transistors.The diverting switch transistor has first end, second end and gate.Transistorized first end of diverting switch couples the gate of shunting driving transistors.Transistorized second end of diverting switch couples the gate of driving transistors.The transistorized gate of diverting switch receives and shows controlling signal.
In one embodiment of this invention, driving transistors and display switch transistor arrangement are within the picture element array.Shunting driving transistors and diverting switch transistor arrangement are outside the picture element array.
In one embodiment of this invention, disturbing signal is a period signal.Disturbing signal respectively carries out amplitude size identical anti-phase disturbance in positive period with negative cycle with no-voltage position standard.
From another angle, the present invention proposes a kind of driving method of image element structure.Image element structure comprises data switch transistor, storage capacitors, driving transistors and Organic Light Emitting Diode.The data switch transistor has first end, second end and gate.Storage capacitors has first end and second end.Driving transistors has first end, second end and gate.Second end of data transistor couples first end of storage capacitors.Second end of storage capacitors couples the gate of driving transistors.First end of driving transistors and second end couple respectively decides voltage and Organic Light Emitting Diode.Driving method comprises according to scanning signal conducting data switch transistor.When the data switch transistor turns, first end of data signals to storage capacitors can be provided, use through driving transistors and drive Organic Light Emitting Diode.When the data switch transistor ends, see through the disturbance switching transistor, first end of disturbing signal to storage capacitors is provided.
Based on above-mentioned, when the present invention stops to provide data signals to image element structure, can provide disturbing signal to image element structure.Thus, can promote the life-span of image element structure.
For above-mentioned feature and advantage of the present invention can be become apparent, embodiment cited below particularly, and cooperate appended graphic being described in detail below.
Description of drawings
Fig. 1 is the synoptic diagram of known a kind of image element structure.
Fig. 2 is the synoptic diagram according to a kind of image element structure of the first embodiment of the present invention.
Fig. 3 is the synoptic diagram according to a kind of disturbing signal of the first embodiment of the present invention.
Fig. 4 is the synoptic diagram of a kind of mode of operation of Fig. 2.
Fig. 5 is the synoptic diagram of the another kind of mode of operation of Fig. 2.
Fig. 6 is the synoptic diagram according to a kind of drive waveforms of the first embodiment of the present invention.
Fig. 7 is the process flow diagram according to the driving method of a kind of image element structure of the first embodiment of the present invention.
Fig. 8 is the synoptic diagram according to a kind of image element structure of the first embodiment of the present invention.
Fig. 9 is the synoptic diagram of a kind of mode of operation of Fig. 8.
Figure 10 is the synoptic diagram of the another kind of mode of operation of Fig. 8.
Figure 11 is the synoptic diagram according to a kind of disturbing signal of the first embodiment of the present invention.
[primary clustering symbol description]
10,11: image element structure
Ccs, Cs: storage capacitors
Cth: critical voltage electric capacity
P1: data switching transistor
P2: disturbance switching transistor
P3: display switch transistor
P4: driving transistors
P5: diverting switch transistor
P6: shunting driving transistors
D1:OLED
DL: data line
GL: sweep trace
CSL: disturbing signal
DCL: show controlling signal
C, S, G, D: end points
Vdd: decide voltage
TFT_S, TFT_D: transistor
Io, I SD: electric current
S701~S703: each step of driving method.
?
Embodiment
Known image element structure has the problem of high current stress, shortens the life-span of image element structure easily.
Review, embodiments of the invention provide multiple image element structure, can improve known problem.
First kind of image element structure:
With critical voltage electric capacity between first end and gate of driving transistors, can strengthen the critical voltage of driving transistors.Can solve driving transistors because of the factors such as difference, long-time operation or environment temperature on the processing procedure, and make its operating characteristic difference to some extent, and then cause its critical voltage (ThresholdVoltage) variation.Thus, the electric current of driving transistors output then is not subject to critical voltage influences.
2. from then on the disturbing signal that amplitude equates about in the of is imported in the outside of image element structure, and disturbing signal can make the electric current (voltage) by OLED do disturbance in a fixed value by this.Therefore,, can improve because of driving transistors must continue to provide big electric current to OLED, and be in high current stress (highcurrentstress) the deterioration problem that causes, can prolong transistorized serviceable life if be used in white picture for a long time when showing.In addition, because human eye has the persistence of vision phenomenon, therefore as long as the frequency of disturbing signal is higher than the frequency of human eye institute energy identification, the display brightness of picture element almost can present a fixed value.
Second kind of image element structure:
1. use the method for shunting (SharingCurrent), can improve when the white picture of long-time demonstration, driving transistors must continue to provide big electric current to OLED, and is in high current stress (highcurrentstress) the deterioration problem that causes, and can prolong the serviceable life of TFT.
2. utilize this image element structure, the operating voltage of driving transistors is reduced.Therefore can select withstand voltage lower driving transistors for use, reduce cost.Simultaneously also can reduce power consumption.
(a) provide data signals to driving transistors, its voltage can be reduced to former
Figure 201010118833X100002DEST_PATH_IMAGE002
(b) in like manner, when utilizing disturbing signal that this image element structure is carried out disturbance, the voltage of disturbing signal also can be reduced to former
Figure 783962DEST_PATH_IMAGE002
Elaborate embodiments of the invention below with reference to the accompanying drawings, accompanying drawing is for example understood example embodiment of the present invention, wherein same the or similar step of same numeral indication.
First embodiment
(1) image element structure explanation
Fig. 2 is the synoptic diagram according to a kind of image element structure of the first embodiment of the present invention.Please refer to Fig. 2, in the present embodiment, image element structure has used the framework of 4T2C.Image element structure 10 comprises storage capacitors Ccs, critical voltage capacitor C th, data switch transistor P1, disturbance switching transistor P2, display switch transistor P3, driving transistors P4 and OLEDD1.In the present embodiment, data switch transistor P1 is that example describes with the N channel transistor, and disturbance switching transistor P2, display switch transistor P3 and driving transistors P4 are that example describes with the P channel transistor, but the present invention is not limited to this.
The gate of data switch transistor P1 couples sweep trace GL, can receive the scanning signal.First end of data switch transistor P1 couples data line DL, can receive data signals.Second end of data switch transistor P1 couples first end of storage capacitors Ccs and second end of disturbance switching transistor P2.First end of disturbance switching transistor P2 can receive disturbing signal CSL.The gate of disturbance switching transistor P2 couples sweep trace GL.
Second end of storage capacitors Ccs couples first end of critical voltage capacitor C th and the gate of driving transistors P4.First end of driving transistors P4 couples second end of deciding voltage Vdd, critical voltage capacitor C th.Second end of driving transistors P4 couples first end of display switch transistor P3.The gate of display switch transistor P3 receives and shows controlling signal DCL.Second end of display switch transistor P3 couples the anode of OLEDD1.The negative electrode of OLEDD1 couples earth terminal.
In the present embodiment, data switch transistor P1, disturbance switching transistor P2 and display switch transistor P3 can be used as the switch use.Driving transistors P4 then is used for driving OLED D1.
In more detail, the data switching transistor P1 scanning signal that can provide according to sweep trace GL and first end that the data signals of data line DL is passed to storage capacitors Ccs is used in conducting.Disturbance switching transistor P2 can cooperate the operation of data switch transistor P1, the disturbing signal CSL of outside input is passed to first end of storage capacitors Ccs.When data switching transistor P1 ends, then conducting of disturbance switching transistor P2; Otherwise when data switching transistor P1 conducting, disturbance switching transistor P2 then ends.
Please note, in the present embodiment, because data switch transistor P1 and disturbance switching transistor P2 are respectively N channel transistor and P channel transistor, so the gate of disturbance switching transistor P2 can couple scanning and interrogate GL, and is shared with the one scan signal with data switch transistor P1.Thus, the then operation that need not additionally provide controlling signal to control disturbance switching transistor P2, but the present invention is not limited to this.In other embodiments, also can provide controlling signal to control the operation of disturbance switching transistor P2 in addition.
Driving transistors P4 can be according to the voltage of G end points driving OLED D1.Display switch transistor P3 can determine whether conducting according to showing controlling signal DCL.Whether show that controlling signal DCL inputs to the gate of display switch transistor P3, can be used as control OLEDD1 can be by the switch of electric current.When display switch transistor P3 ended, OLEDD1 can be not shinny; When display switch transistor P3 conducting, OLEDD1 can be controlled by driving transistors P4 and the brightness of sending corresponding GTG.
On the other hand, but the main critical voltage of storage drive transistor P4 of critical voltage capacitor C th.But storage capacitors Ccs is storage data line data signals that DL provides mainly.In addition, be noted that, first end of storage capacitors (C end points) more is connected with second end of disturbance switching transistor P2, the external disturbing signal CSL of first end of disturbance switching transistor P2, mainly be for data signals during a picture frame, become the data signals that has disturbing signal CSL.Disturbing signal CSL to adjust the output current of driving transistors P4, makes OLEDD1 send the brightness that will show by the gate that storage capacitors Ccs is coupled to driving transistors P4.
(2), picture element driving method
(1), the electric current by OLEDD1
Figure DEST_PATH_IMAGE004
:
Figure DEST_PATH_IMAGE006
(1-1)
In the above-mentioned formula (1-1),
Figure DEST_PATH_IMAGE008
Be oxide layer electric capacity (OxideCapacitance). Be electron drift rate (ElectronMobility).W is channel width (ChannelWidth).L is passage length (ChannelLength).
Figure 950370DEST_PATH_IMAGE004
Electric current for the driving transistors P4 that flows through.Wherein
Figure DEST_PATH_IMAGE012
Pressure reduction for end points S and end points G.
Figure DEST_PATH_IMAGE014
Critical voltage for driving transistors P4.The present embodiment hypothesis
Figure 976445DEST_PATH_IMAGE008
, , W and L be fixed value.Therefore can get following formula (1-2), wherein K is a constant.
Figure DEST_PATH_IMAGE016
(1-2)
Then, can obtain following formula (1-3) by formula (1-1).
Figure DEST_PATH_IMAGE018
(1-3)
In addition, end points S is connected to and decides voltage Vdd, and therefore the voltage of end points S can get following formula (1-4), wherein with to decide voltage Vdd identical
Figure DEST_PATH_IMAGE020
Voltage for end points S.
(1-4)
With formula (1-4) substitution formula (1-3), can get following formula (1-5), wherein Voltage for end points G.
Figure DEST_PATH_IMAGE026
(1-5)
(2), critical voltage stores:
Fig. 3 is the synoptic diagram according to a kind of disturbing signal of the first embodiment of the present invention.Fig. 4 is the synoptic diagram of a kind of mode of operation of Fig. 2.Please merge with reference to Fig. 3 and Fig. 4, in the present embodiment, disturbing signal CSL does the identical disturbance (± Δ) of amplitude up and down with the ground voltage position that is as the criterion.In positive period, the voltage of disturbing signal CSL
Figure DEST_PATH_IMAGE028
Represent it with Vcsh; At negative cycle, the voltage of disturbing signal CSL is represented it with Vcsl, as following formula (1-6).
Figure DEST_PATH_IMAGE030
Or
Figure DEST_PATH_IMAGE032
(1-6)
The dotted line representation switch is a cut-off state among Fig. 4, that is this moment, disturbance switching transistor P2 and display switch transistor P3 were cut-off state, and data switching transistor P1 is a conducting state.When
Figure DEST_PATH_IMAGE034
Be charged to
Figure DEST_PATH_IMAGE036
The time, driving transistors P4 can by (because
Figure DEST_PATH_IMAGE038
).This moment end points C voltage and the voltage of the data signals that provided of data line DL
Figure DEST_PATH_IMAGE040
Identical, as following formula (1-7).
The voltage of C end points:
Figure DEST_PATH_IMAGE042
(1-7)
Hold above-mentionedly, the voltage of end points G is shown in following formula (1-8).The cross-pressure of storage capacitors Ccs
Figure DEST_PATH_IMAGE044
Shown in following formula (1-9).
Figure DEST_PATH_IMAGE046
(1-8)
Figure DEST_PATH_IMAGE048
(1-9)
(3), disturbing signal:
Fig. 5 is the synoptic diagram of the another kind of mode of operation of Fig. 2.Among Fig. 5, the dotted line representation switch is a cut-off state, that is this moment, data switch transistor P1 was a cut-off state, and disturbance switching transistor P2 and display switch transistor P3 are conducting state.
As disturbing signal CSL during at negative cycle, can obtain following formula (1-10), this moment end points C voltage Vc such as following formula (1-11).
Figure 58464DEST_PATH_IMAGE032
(1-10)
Figure DEST_PATH_IMAGE050
(1-11)
The potential change amount of end points C
Figure DEST_PATH_IMAGE052
As following formula (1-12).The potential change amount of end points G
Figure DEST_PATH_IMAGE054
As following formula (1-13).
Figure DEST_PATH_IMAGE056
(1-12)
Figure DEST_PATH_IMAGE058
(1-13)
Then can by following formula (1-14) push away the voltage of end points G, and by following formula (1-15) push away the electric current of the OLEDD1 that flows through.
Figure DEST_PATH_IMAGE060
(1-14)
Figure DEST_PATH_IMAGE062
(1-15)
In like manner can analogize, as disturbing signal CSL during in positive period, in the formula (1-15)
Figure DEST_PATH_IMAGE064
Can by
Figure DEST_PATH_IMAGE066
Replace, as following formula (1-15 ').
Figure DEST_PATH_IMAGE068
(1-15’)
If definition
Figure DEST_PATH_IMAGE070
Suppose
Figure 507025DEST_PATH_IMAGE030
Become through disturbance
Figure 836375DEST_PATH_IMAGE032
Situation under, the electric current of the OLEDD1 that flows through is then for following formula (1-16).
Figure DEST_PATH_IMAGE072
(1-16)
Suppose Become through disturbance
Figure 828788DEST_PATH_IMAGE030
Situation under, in the formula (1-16)
Figure DEST_PATH_IMAGE074
Can by
Figure DEST_PATH_IMAGE076
Replace, as following formula (1-16 ').
Figure DEST_PATH_IMAGE078
(1-16’)
(3), picture element wave mode design
Fig. 6 is the synoptic diagram according to a kind of drive waveforms of the first embodiment of the present invention.Fig. 7 is the process flow diagram according to the driving method of a kind of image element structure of the first embodiment of the present invention.Please merge with reference to Fig. 6 and Fig. 7.
Among Fig. 6, whether the scanning signal may command of sweep trace GL writes storage capacitors Ccs with the data signals of data line DL.Whether the output current that shows controlling signal DCL may command driving transistors P4 flows into OLEDD1.Disturbing signal CSL is the disturbing signal of the outside input of picture element, and this signal is with no-voltage position standard, the periodic perturbation of work ± Δ. Can make driving transistors P4 produce the voltage signal of electric current output.T1 is that critical voltage stores and data write during this time.T2 is the data disturbance during this time.
In Fig. 7, whether data switching transistor P1 can determine conducting (step S701) according to the scanning signal.When data switch transistor P1 conducting, the data signals of data line DL can be passed to first end of storage capacitors Ccs, uses through driving transistors P4 and comes driving OLED D1(step S702), as during T1.When data switch transistor P1 by the time, see through disturbance switching transistor P2, disturbing signal CSL can be passed to first end (step S703) of storage capacitors Ccs, as during T2.
Note that when disturbing signal CSL carries out periodic disturbance that the electric current of the driving transistors P4 that flows through and the electric current of the OLEDD1 that flows through also can periodic thereupon disturbances.This practice can effectively be improved the situation of known high current stress, improves the situation of assembly deterioration, and can prolong the life-span of image element structure.Moreover, the frequency of disturbing signal CSL be higher than human eye can identification frequency the time, the brightness that human eye still can send OLEDD1 is to be a fixed value, and the situation that does not have a flicker takes place.
What deserves to be mentioned is, though image element structure and driving method thereof have been depicted a possible kenel in the foregoing description, usually know that the knowledgeable should know but have in the affiliated technical field, each manufacturer is all different for the design of image element structure and driving method thereof, and therefore application of the present invention is when being not restricted to the possible kenel of this kind.In other words, so long as when stopping to provide data signals, provide disturbing signal, be to have met spiritual place of the present invention just to image element structure to image element structure.Below know that the knowledgeable can further understand spirit of the present invention for several embodiment usually so that this area has again, and implement the present invention.
Second embodiment
(1) image element structure explanation
Fig. 8 is the synoptic diagram according to a kind of image element structure of the first embodiment of the present invention.Fig. 9 is the synoptic diagram of a kind of mode of operation of Fig. 8.Figure 10 is the synoptic diagram of the another kind of mode of operation of Fig. 8.Figure 11 is the synoptic diagram according to a kind of disturbing signal of the first embodiment of the present invention.Please merge with reference to Fig. 8~Figure 11.The image element structure 11 of Fig. 8 is similar with the image element structure of Fig. 2.Difference is that image element structure 11 more comprises shunting driving transistors P6 and diverting switch transistor P5.Image element structure 11 has used dividing technology, is the image element structure of 6T2C.
First end of shunting driving transistors P6 couples decides voltage Vdd.Second end of shunting driving transistors P6 couples second end of driving transistors P4.Diverting switch transistor P5 has first end, second end and gate.First end of diverting switch transistor P5 couples the gate of shunting driving transistors P6.Second end of diverting switch transistor P5 couples the gate of driving transistors P4.The gate of diverting switch transistor P5 can receive and show controlling signal DCL.In the present embodiment, shunting driving transistors P6 and driving transistors P4 are all the P channel transistor, and diverting switch transistor P5 and display switch transistor P3 are all the P channel transistor.
The function of the function of diverting switch transistor P5 and display switch transistor P3 is similar, can be used as switch and uses.The function of shunting driving transistors P6 and the function of driving transistors P4 are similar, can be used to driving OLED D1.When display switch transistor P3 conducting, also conducting thereupon of diverting switch transistor P5; Otherwise when display switch transistor P3 ended, diverting switch transistor P5 also can end thereupon.It should be noted that, when display switch transistor P3 and diverting switch transistor P5 conducting, the gate of shunting driving transistors P6 can obtain identical haply voltage with the gate of driving transistors P4, makes shunting driving transistors P6 have identical mode of operation with driving transistors P4.The electric current that deciding voltage Vdd provides can see through shunting driving transistors P6 and driving transistors P4 respectively and flow to OLEDD1.In other words, shunting driving transistors P6 has the shunting function, can share the electric current of the driving transistors P4 that flows through.
Image element structure 11 not only have with Fig. 2 in the similar function of image element structure 10, and the operating voltage of driving transistors P4, shunting driving transistors P6 is reduced.Driving transistors P4 and shunting driving transistors P6 can select for use withstand voltage low transistor to implement, and also can reduce power consumption simultaneously.Below provide the formula explanation to consider and examine for haveing the knack of art technology person.
(2), picture element driving method
The output current of driving transistors P4 such as formula (2-1), wherein
Figure 91927DEST_PATH_IMAGE008
Be oxide layer electric capacity.W is a channel width.L is a passage length.
Figure 908573DEST_PATH_IMAGE006
(2-1)
Here suppose
Figure 707902DEST_PATH_IMAGE008
,
Figure 293604DEST_PATH_IMAGE010
, W and L be fixed value.Therefore order
Figure 723448DEST_PATH_IMAGE016
(2-2)
Above-mentioned K is a constant.
So (2-1) can be write as following formula (2-3):
Figure 27391DEST_PATH_IMAGE018
(2-3)
Figure 364831DEST_PATH_IMAGE022
(2-4)
With formula (2-4) substitution formula (2-3), can get formula (2-5).
Figure 73548DEST_PATH_IMAGE026
(2-5)
Critical voltage stores: when disturbance switching transistor P2, display switch transistor P3, diverting switch transistor P5 are cut-off state with shunting driving transistors P6, data switch transistor P1 is conducting state (as shown in Figure 9).
When
Figure 471032DEST_PATH_IMAGE034
Being charged to electricity arrives
Figure 199953DEST_PATH_IMAGE036
The time, driving transistors P4 be cut-off state (because
Figure 341085DEST_PATH_IMAGE038
).
When The time or work as
Figure 735343DEST_PATH_IMAGE032
The time (2-6)
The voltage of end points C
Figure DEST_PATH_IMAGE082
(2-7)
In the above-mentioned formula (2-7), m is a real number, and
Figure DEST_PATH_IMAGE084
Promptly suppose present embodiment Be first embodiment
Figure 872932DEST_PATH_IMAGE086
M doubly.
The voltage of end points G is
Figure DEST_PATH_IMAGE088
(2-8)
Then
Figure DEST_PATH_IMAGE090
Last cross-pressure
Figure DEST_PATH_IMAGE092
(2-9)
Disturbing signal: when data switching transistor P1 is a cut-off state, disturbance switching transistor P2, display switch transistor P3, diverting switch transistor P5 are conducting state (as shown in figure 10).
As disturbing signal CSL during at negative cycle.
Figure 939458DEST_PATH_IMAGE032
(2-10)
Figure 478893DEST_PATH_IMAGE050
(2-11)
The potential change amount of end points C such as following formula (2-12).The potential change amount of end points G such as following formula (2-13).
Figure DEST_PATH_IMAGE094
(2-12)
Figure DEST_PATH_IMAGE096
(2-13)
(2-14)
Then can push away the electric current of the driving transistors P4 that flows through
Figure DEST_PATH_IMAGE100
, as following formula (2-15).Flow through and shunt the electric current of driving transistors P6
Figure DEST_PATH_IMAGE102
, as following formula (2-16).
Figure DEST_PATH_IMAGE104
(2-15) (2-16)
In like manner can analogize, as disturbing signal CSL during in positive period, in formula (2-15) and the formula (2-16) Can by
Figure 298524DEST_PATH_IMAGE066
Replace, as following formula (2-15 ') and formula (2-16 ').
Figure DEST_PATH_IMAGE108
(2-15’)
Figure DEST_PATH_IMAGE110
(2-16’)
If definition
Figure DEST_PATH_IMAGE112
Figure DEST_PATH_IMAGE114
。Suppose
Figure 906091DEST_PATH_IMAGE030
Become through disturbance
Figure 438048DEST_PATH_IMAGE032
Situation under, formula (2-15) can be rewritten as following formula (2-17), formula (2-16) can be rewritten as following formula (2-18).
Figure DEST_PATH_IMAGE116
(2-17)
Figure DEST_PATH_IMAGE118
(2-18)
Suppose
Figure 738449DEST_PATH_IMAGE032
Become through disturbance
Figure 663679DEST_PATH_IMAGE030
Situation under, in formula (2-17), the formula (2-18) Can by
Figure 74118DEST_PATH_IMAGE076
Replace, as following formula (2-17 '), formula (2-18 ').
Figure DEST_PATH_IMAGE120
(2-17’)
Figure DEST_PATH_IMAGE122
(2-18’)
Conclusion: the influence of critical voltage is offset, and can make the output current of shunting driving transistors P6 and driving transistors P4 not influenced by critical voltage variation.
Then, analyze the electric current that passes through driving transistors P4, shunting driving transistors P6 and OLEDD1.Identical at the flow through magnitude of current of OLEDD1 of this hypothesis present embodiment with first embodiment, as formula (2-19).In addition, hypothesis driven transistor P4 is identical or close with the K value of shunting driving transistors P6, as formula (2-20).
Figure DEST_PATH_IMAGE124
(2-19)
Figure DEST_PATH_IMAGE126
(2-20)
By formula (17) and formula (18), and order
Figure DEST_PATH_IMAGE128
Or
Figure DEST_PATH_IMAGE130
(2-21)
Figure DEST_PATH_IMAGE132
(2-22)
In the above-mentioned formula (2-22),
Figure DEST_PATH_IMAGE134
,
Figure DEST_PATH_IMAGE136
,
Figure DEST_PATH_IMAGE138
Be constant.Then, can obtain following formula (2-23).
Figure DEST_PATH_IMAGE140
(2-23)
In the present embodiment, drive picture element transistor P4 with total output current that shunting drives picture element transistor P6 be ( ), can get following formula (2-24), wherein
Figure DEST_PATH_IMAGE144
It is the output current that first embodiment drives picture element transistor P4.On the other hand,
Figure 43954DEST_PATH_IMAGE144
Can be obtained by following formula (2-25), and
Figure DEST_PATH_IMAGE146
Can be obtained by following formula (2-26).
Figure DEST_PATH_IMAGE148
(2-24)
Figure DEST_PATH_IMAGE150
(2-25)
Figure DEST_PATH_IMAGE152
(2-26)
With formula (2-25) and formula (2-26) substitution formula (2-24), can obtain following formula (2-27).
Figure DEST_PATH_IMAGE154
Figure DEST_PATH_IMAGE156
Figure DEST_PATH_IMAGE158
(2-27)
Gained
Figure DEST_PATH_IMAGE160
Two values are arranged
Figure DEST_PATH_IMAGE162
With
Figure DEST_PATH_IMAGE164
Figure DEST_PATH_IMAGE166
?(2-28)
Because
Figure DEST_PATH_IMAGE168
And
Figure DEST_PATH_IMAGE170
When
Figure DEST_PATH_IMAGE172
The time:
Figure DEST_PATH_IMAGE174
(closing),
Figure DEST_PATH_IMAGE176
(not conforming to)
When
Figure DEST_PATH_IMAGE178
The time:
Figure 394164DEST_PATH_IMAGE174
(closing),
Figure DEST_PATH_IMAGE180
(closing)
Therefore, satisfy simultaneously
Figure DEST_PATH_IMAGE182
The time,
Figure DEST_PATH_IMAGE184
(2-29)
Formula (2-29) substitution formula (2-23) formula can obtain the output current of a driving transistors of present embodiment, as following formula (2-30)
Figure DEST_PATH_IMAGE186
(2-30)
Then, order
Figure DEST_PATH_IMAGE188
Figure DEST_PATH_IMAGE190
(2-31)
Figure DEST_PATH_IMAGE192
(2-32)
Conclusion:
1. in the present embodiment, the required operating voltage of the gate of driving transistors P4 and shunting driving transistors is the first embodiment driving transistors P4's
Figure DEST_PATH_IMAGE194
2. in the present embodiment, the voltage of disturbing signal CSL is first embodiment's
Partial current is analyzed:
By formula (2-21) and formula (2-32) formula, checking formula (2-19)
Figure DEST_PATH_IMAGE196
?
Figure DEST_PATH_IMAGE198
Conclusion: the image element structure 11 of present embodiment uses two close driving transistorss (P4, P6), can obtain to pass through the identical size of current of OLEDD1 with first embodiment.
Transistorized power consumption analysis:
Figure DEST_PATH_IMAGE200
(3-33)
Formula (3-33) can be simplified following formula (3-33 ').
Figure DEST_PATH_IMAGE202
(3-33’)
So the power consumption of driving transistors such as following formula (3-34):
Figure DEST_PATH_IMAGE204
(3-34)
Again as can be known by formula (3-34):
Figure DEST_PATH_IMAGE206
(3-35)
Conclusion: present embodiment shunting driving transistors P6 and driving transistors P4 total consumed power are less than the consumed power of the first embodiment driving transistors P4.
(3), picture element wave mode design
Please refer to Figure 11, whether the scanning signal may command of sweep trace GL writes storage capacitors Ccs with the data signals of data line DL.DL represents the signal of a dataline.Show whether controlling signal DCL may command driving transistors P4 and the output current of shunting driving transistors P4 flow into OLEDD1.Disturbing signal CSL is the disturbing signal of the outside input of picture element, and this signal is with no-voltage position standard, work ± Δ NewPeriodic perturbation.
Figure 437303DEST_PATH_IMAGE080
Can make driving transistors P4 and shunting driving transistors P4 produce the voltage signal of electric current output.T1 is that critical voltage stores and data write during this time.T2 is the data disturbance during this time.
Comprehensively above-mentioned, second embodiment not only can reach the similar effect with first embodiment, also can reduce driving transistors and the gate operating voltage of shunting driving transistors and the voltage of disturbing signal.This practice not only can effectively reduce the total power consumption of image element structure 11.Driving transistors is also comparatively loose with the specification limits of shunting driving transistors, transistorized selecting for use when helping implementing.
In addition, have the knack of the image element structure that art technology person also can change the foregoing description according to its demand.For instance, in a second embodiment, shunting driving transistors P6 and diverting switch transistor P5 can be configured in outside the picture element array, for example configurable in the frame of display.So can effectively improve the aperture opening ratio (aperturerate) of image element structure 11.
Again for example, among first embodiment, storage capacitors Ccs and inessential member.Have the knack of art technology person and can omit storage capacitors Ccs according to its demand.
In sum, when the present invention stops to provide data signals to image element structure, can provide disturbing signal to image element structure.Thus, can promote the life-span of image element structure.In addition, embodiments of the invention also have following effect:
1. critical voltage electric capacity of configuration between first end of driving transistors and gate terminal can reduce the variation of critical voltage, makes the brightness performance of picture element more stable.
2. configurable shunting driving transistors and diverting switch transistor in image element structure are used the magnitude of current of sharing driving transistors.So not only can reduce the total power consumption of image element structure.The gate operating voltage of driving transistors and shunting transistor also can be lowered, also and transistorized specification limits also can reduce transistorized selecting for use when implementing.In addition, the voltage of disturbing signal also can be lowered.
3. shunting driving transistors and diverting switch transistor are configurable outside the picture element array, use the aperture opening ratio that improves image element structure.
Though the present invention discloses as above with embodiment; right its is not in order to limit the present invention; have in the technical field under any and know the knowledgeable usually; without departing from the spirit and scope of the present invention; when doing a little change and retouching, so protection scope of the present invention is as the criterion when looking accompanying the claim person of defining.

Claims (8)

1. image element structure, it is characterized in that comprising: a storage capacitors has one first end and one second end; One data switch transistor provides first end of a data signals to this storage capacitors according to the one scan signal; One disturbance switching transistor, when this data switching transistor ended, this disturbance switching transistor provided first end of a disturbing signal to this storage capacitors; One driving transistors has one first end, one second end and a gate, and first end of this driving transistors couples certain voltage, and the gate of this driving transistors couples second end of this storage capacitors; One display switch transistor has one first end, one second end and a gate, and transistorized first end of this display switch couples second end of this driving transistors, and the transistorized gate of this display switch receives one and shows controlling signal; And an Organic Light Emitting Diode, its anode couples transistorized second end of this display switch, and its negative electrode couples an earth terminal.
2. image element structure according to claim 1, it is characterized in that: wherein this data switch transistor has one first end, one second end and a gate, first end of this data switching transistor couples a data line and receives this data signals, the transistorized gate of this data switch couples the one scan line and receives this scanning signal, and transistorized second end of this data switch couples first end of this storage capacitors.
3. image element structure according to claim 2, it is characterized in that: wherein this disturbance switching transistor has one first end, one second end and a gate, first termination of this disturbance switching transistor is received this disturbing signal, the gate of this disturbance switching transistor couples this sweep trace and receives this scanning signal, second end of this disturbance switching transistor couples first end of this storage capacitors, and this disturbance switching transistor and this data switching transistor are made up of a P channel transistor and a N channel transistor.
4. image element structure according to claim 1 is characterized in that more comprising: a critical voltage electric capacity is coupled between transistorized first end of this display switch and the gate.
5. image element structure according to claim 1, it is characterized in that more comprising: a shunting driving transistors, have one first end, one second end and a gate, first end of this shunting driving transistors couples this and decides voltage, and second end of this shunting driving transistors couples second end of this driving transistors; An and diverting switch transistor, have one first end, one second end and a gate, transistorized first end of this diverting switch couples the gate of this shunting driving transistors, transistorized second end of this diverting switch couples the gate of this driving transistors, and the transistorized gate of this diverting switch receives this demonstration controlling signal.
6. image element structure according to claim 5 is characterized in that: wherein this driving transistors and this display switch transistor arrangement are within a picture element array, and this shunting driving transistors and this diverting switch transistor arrangement are outside this picture element array.
7. image element structure according to claim 5 is characterized in that: wherein this disturbing signal is a period signal, and this disturbing signal respectively carries out amplitude size identical anti-phase disturbance in positive period with negative cycle with no-voltage position standard.
8. the driving method of an image element structure, it is characterized in that: this image element structure comprises a data switch transistor, one storage capacitors, one driving transistors and an Organic Light Emitting Diode, this data switch transistor has one first end, one second end and a gate, this storage capacitors has one first end and one second end, this driving transistors has one first end, one second end and a gate, second end of this data transistor couples first end of this storage capacitors, second end of this storage capacitors couples the gate of this driving transistors, first end of this driving transistors and second end couple certain voltage and this Organic Light Emitting Diode respectively, this driving method comprises: according to one scan signal conducting one data switch transistor; When this data switch transistor turns, first end of a data signals to this storage capacitors is provided, use through this driving transistors and drive this Organic Light Emitting Diode; And when this data switch transistor ends, see through a disturbance switching transistor, first end of a disturbing signal to this storage capacitors is provided.
CN201010118833A 2010-03-08 2010-03-08 Pixel structure and driving method thereof Expired - Fee Related CN101763780B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201010118833A CN101763780B (en) 2010-03-08 2010-03-08 Pixel structure and driving method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201010118833A CN101763780B (en) 2010-03-08 2010-03-08 Pixel structure and driving method thereof

Publications (2)

Publication Number Publication Date
CN101763780A true CN101763780A (en) 2010-06-30
CN101763780B CN101763780B (en) 2012-10-03

Family

ID=42494924

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201010118833A Expired - Fee Related CN101763780B (en) 2010-03-08 2010-03-08 Pixel structure and driving method thereof

Country Status (1)

Country Link
CN (1) CN101763780B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015149399A1 (en) * 2014-04-01 2015-10-08 深圳市华星光电技术有限公司 Pixel drive circuit and drive method of oled display

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6229506B1 (en) * 1997-04-23 2001-05-08 Sarnoff Corporation Active matrix light emitting diode pixel structure and concomitant method
US20050068271A1 (en) * 2003-09-29 2005-03-31 Shin-Tai Lo Active matrix organic electroluminescence display driving circuit
CN101055697A (en) * 2006-04-14 2007-10-17 统宝光电股份有限公司 Display image system capable of reducing color non-uniform phenomenon

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6229506B1 (en) * 1997-04-23 2001-05-08 Sarnoff Corporation Active matrix light emitting diode pixel structure and concomitant method
US20050068271A1 (en) * 2003-09-29 2005-03-31 Shin-Tai Lo Active matrix organic electroluminescence display driving circuit
CN101055697A (en) * 2006-04-14 2007-10-17 统宝光电股份有限公司 Display image system capable of reducing color non-uniform phenomenon

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015149399A1 (en) * 2014-04-01 2015-10-08 深圳市华星光电技术有限公司 Pixel drive circuit and drive method of oled display

Also Published As

Publication number Publication date
CN101763780B (en) 2012-10-03

Similar Documents

Publication Publication Date Title
US8963907B2 (en) Pixel circuit and driving method thereof
CN100590691C (en) Display and its pixel circuit
CN104167173B (en) Pixel circuit for active organic light-emitting diode displayer
CN104062784B (en) A kind of panel detection circuit and display panel
CN102968953B (en) Display panel, organic light emitting diode driving circuit and method thereof
CN104700783B (en) The driving method of pixel-driving circuit
CN102708792B (en) Pixel cell driving circuit, pixel cell driving method, pixel cell and display device
CN101996582B (en) Pixel driving circuit of organic light-emitting diode
CN103500556B (en) A kind of image element circuit and driving method, thin film transistor backplane
CN102655145B (en) Static releasing protection circuit and working method thereof
CN104916257A (en) Pixel circuit, drive method thereof, display panel and display device
CN105405406A (en) Gate drive circuit and display using same
CN102034426B (en) Organic light-emitting display and driving method
CN106531077A (en) Pixel structure and driving method thereof
JP2012113812A (en) Shift register unit, gate driving circuit, and display device
CN105957474B (en) Pixel-driving circuit and its driving method, array substrate, display device
CN105679243B (en) AMOLED pixel-driving circuit and image element driving method
CN105513552A (en) Driving circuit, driving method and display device
CN104637445A (en) AMOLED (Active Matrix/Organic Light Emitting Diode) pixel driving circuit and pixel driving method
CN101192374A (en) Organic luminous display panel and its voltage drive organic light emitting pixel
CN104269139A (en) Pixel structure and driving method thereof
CN106611586B (en) Pixel-driving circuit, driving method, organic light emitting display panel and display device
CN103198788A (en) Pixel circuit, organic electroluminescence display panel and display device
CN104575393A (en) AMOLED (active matrix organic light emitting display) pixel driving circuit and pixel driving method
CN105469751A (en) Ghost shadow elimination method and driving method, driving device, panel and display system thereof

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
ASS Succession or assignment of patent right

Owner name: CHINA PROJECTION TUBE CO., LTD.

Free format text: FORMER OWNER: CPTF OPTRONICS CO., LTD.

Effective date: 20130605

Free format text: FORMER OWNER: CHINA PROJECTION TUBE CO., LTD.

Effective date: 20130605

C41 Transfer of patent application or patent right or utility model
COR Change of bibliographic data

Free format text: CORRECT: ADDRESS; FROM: 350015 FUZHOU, FUJIAN PROVINCE TO: TAIWAN, CHINA

TR01 Transfer of patent right

Effective date of registration: 20130605

Address after: Taiwan, China

Patentee after: Chunghwa Picture Tubes Ltd.

Address before: 350015 No. 1 Xingye Road, Mawei Science Park, Fujian, Fuzhou

Patentee before: CPTF Optronics Co., Ltd.

Patentee before: Chunghwa Picture Tubes Ltd.

CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20121003

Termination date: 20200308

CF01 Termination of patent right due to non-payment of annual fee