CN101763780B

CN101763780B - Pixel structure and driving method thereof

Info

Publication number: CN101763780B
Application number: CN201010118833A
Authority: CN
Inventors: 陈屏先; 陈弼先
Original assignee: CPTF Optronics Co Ltd; Chunghwa Picture Tubes Ltd
Current assignee: Chunghwa Picture Tubes Ltd
Priority date: 2010-03-08
Filing date: 2010-03-08
Publication date: 2012-10-03
Anticipated expiration: 2030-03-08
Also published as: CN101763780A

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 OLED.

Background technology

Use Organic Light Emitting Diode (organic light emitting diode; OLED) OLED (organic light emitting display) 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 OLED has above-mentioned advantage, but still some problem needs to be resolved hurrily.

Fig. 1 is the synoptic diagram of a kind of image element structure of convention.Please with reference 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 OLED D1 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 OLED D1 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 through OLED D1.

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 (Threshold Voltage) to produce variation, and then make electric current I o produce change, and influence the performance in the picture element brightness through OLED D1.

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 OLED D1, and transistor T FT_D can be in high current stress (high current stress) for a long time, is prone to cause the deterioration problem, reduces serviceable life.

Summary of the invention

The present invention provides a kind of image element structure, can prolong the life-span of image element structure.

The present 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 so that the no-voltage position is accurate.

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 letting the above-mentioned feature and advantage of the present invention can be more obviously understandable, hereinafter is special lifts embodiment, and cooperates appended graphic elaborating as follows.

Description of drawings

Fig. 1 is the synoptic diagram of a kind of image element structure of convention.

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

The image element structure of convention 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 the problem of convention.

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 (Threshold Voltage) 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) through 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 (high current stress) 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 ability 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 (Sharing Current); 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 (high current stress) 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) data signals to driving transistors is provided, 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

.Set forth embodiments of the invention in detail below with reference to accompanying drawing, the for example clear example embodiment of the present invention of accompanying drawing, the wherein same 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 with reference 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 OLED D1.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 OLED D1.The negative electrode of OLED D1 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 operation that then need not extraly 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 OLED D1 can be through the switch of electric current.When display switch transistor P3 ended, OLED D1 can be not shinny; When display switch transistor P3 conducting, OLED D1 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 OLED D1 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), pass through the electric current of OLED D1:

（1-1）

In the above-mentioned formula (1-1),

is oxide layer electric capacity (Oxide Capacitance).

is electron drift rate (Electron Mobility).W is channel width (Channel Width).L is passage length (Channel Length).

is the electric current of the driving transistors P4 that flows through.Wherein is the pressure reduction of end points S and end points G.

is the critical voltage of driving transistors P4.Present embodiment hypothesis

;

; W and L are fixed value.Therefore can get formula (1-2), wherein K is a constant.

（1-2）

Then, can obtain formula (1-3) by formula (1-1).

（1-3）

In addition; End points S is connected to and decides voltage Vdd; The voltage of end points S is with to decide voltage Vdd identical; Therefore can get formula (1-4), wherein is the voltage of end points S.

（1-4）

With formula (1-4) substitution formula (1-3); Can get formula (1-5), wherein

is the voltage of end points G.

（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

is represented it with Vcsh; At negative cycle, the voltage of disturbing signal CSL is represented it with Vcsl, like following formula (1-6).

or (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

was charged to

, driving transistors P4 can be by (because

).This moment, the voltage

of the data signals that provided of voltage and data line DL of end points C was identical, like following formula (1-7).

The voltage of C end points: (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 is shown in following formula (1-9).

（1-8）

（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 formula (1-10), this moment end points C voltage Vc such as following formula (1-11).

（1-10）

（1-11）

The potential change amount of end points C

is like following formula (1-12).The potential change amount of end points G

is like following formula (1-13).

（1-12）

（1-13）

Then can by formula (1-14) push away the voltage of end points G, and by formula (1-15) push away the electric current of the OLED D1 that flows through.

（1-14）

（1-15）

In like manner can analogize; As disturbing signal CSL during in positive period;

in the formula (1-15) can be replaced by

, like following formula (1-15 ').

（1-15’）

If definition

.Suppose

and become under the situation of

that the electric current of the OLED D1 that flows through then is formula (1-16) through disturbance.

（1-16）

Suppose

and become under the situation of

through disturbance;

in the formula (1-16) can be replaced by

, like following formula (1-16 ').

（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 OLED D1.Disturbing signal CSL is the disturbing signal of the outside input of picture element, and this signal is accurate with the no-voltage position, 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, use through driving transistors P4 and come 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 electric current of the driving transistors P4 that flows through and the OLED D1 that flows through also can periodic thereupon disturbance.This practice can effectively be improved the situation of the high current stress of convention, 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, human eye still can be with the brightness that OLED D1 sends is 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; But having common knowledge the knowledgeable in the affiliated technical field should know; 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 to image element structure, provide disturbing signal, just be to have met spirit of the present invention place to image element structure.Below lift several embodiment again so that this area has the understanding spirit of the present invention that common knowledge the knowledgeable can be further, and embodiment of 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 OLED D1.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 providing the formula explanation to supply to have the knack of art technology person considers and examines.

(2), picture element driving method

The output current of driving transistors P4 such as formula (2-1), wherein

is oxide layer electric capacity.W is a channel width.L is a passage length.

（2-1）

Here suppose

;

; W and L are fixed value.Therefore order

（2-2）

Above-mentioned K is a constant.

So (2-1) can be write as formula (2-3):

（2-3）

（2-4）

With formula (2-4) substitution formula (2-3), can get formula (2-5).

（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 being charged to electricity to as

, driving transistors P4 is cut-off state (because

).

When

or when when (2-6)

The voltage of end points C (2-7)

In the above-mentioned formula (2-7); M is a real number, and

.Assuming that the present embodiment

is the first embodiment of the

m times.

The voltage of end points G is

(2-8)

Then

goes up cross-pressure

(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 (shown in figure 10).

As disturbing signal CSL during at negative cycle.

（2-10）

（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).

（2-12）

（2-13）

（2-14）

Then can push away the electric current

of the driving transistors P4 that flows through, like following formula (2-15).Flow through and shunt the electric current

of driving transistors P6, like following formula (2-16).

（2-15）（2-16）

in formula (2-15) and the formula (2-16) can be replaced by

, like following formula (2-15 ') and formula (2-16 ').

（2-15’）

（2-16’）

If definition

.

。Suppose and become under the situation of

through disturbance; Formula (2-15) can be rewritten as formula (2-17), and formula (2-16) can be rewritten as formula (2-18).

（2-17）

（2-18）

Suppose

and become under the situation of

through disturbance;

in formula (2-17), the formula (2-18) can be replaced by

, like following formula (2-17 '), formula (2-18 ').

（2-17’）

（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 OLED D1.Identical at the flow through magnitude of current of OLED D1 of this hypothesis present embodiment with first embodiment, like formula (2-19).In addition, hypothesis driven transistor P4 is identical or close with the K value of shunting driving transistors P6, like formula (2-20).

（2-19）

（2-20）

By formula (17) and formula (18), and order

or

(2-21)

（2-22）

In the above-mentioned formula (2-22),

,

,

are constant.Then, can obtain formula (2-23).

（2-23）

In the present embodiment; Driving picture element transistor P4 is (

) with total output current that shunting drives picture element transistor P6; Can get formula (2-24), wherein

is the output current that first embodiment drives picture element transistor P4.On the other hand;

can be obtained by formula (2-25), and

can be obtained by formula (2-26).

（2-24）

（2-25）

（2-26）

With formula (2-25) and formula (2-26) substitution formula (2-24), can obtain formula (2-27).

（2-27）

The resulting

There are two values

and .

（2-28）

Because

and

During as

:

(closing),

(not conforming to)

During as

:

(closing), (closing)

Therefore, when satisfying

simultaneously,

（2-29）

Formula (2-29) substitution formula (2-23) formula can obtain the output current of a driving transistors of present embodiment, like following formula (2-30)

（2-30）

Then, order

；

（2-31）

（2-32）

Conclusion:

1. in the present embodiment, driving transistors P4 is the first embodiment driving transistors P4's with the required operating voltage of gate of shunting driving transistors

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)

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 OLED D1 with first embodiment.

Transistorized power consumption analysis:

（3-33）

Formula (3-33) can be simplified following formula (3-33 ').

（3-33’）

So the power consumption of driving transistors such as following formula (3-34):

（3-34）

Can know by formula (3-34) again:

（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 with reference 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 representes the signal of a data line.Show whether controlling signal DCL may command driving transistors P4 and the output current of shunting driving transistors P4 flow into OLED D1.Disturbing signal CSL is the disturbing signal of the outside input of picture element, and this signal is accurate with the no-voltage position, work ± Δ _NewPeriodic perturbation.

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, can shunting driving transistors P6 and diverting switch transistor P5 be configured in outside the picture element array, for example configurable in the frame of display.So can effectively improve the aperture opening ratio (aperture rate) 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; Has common knowledge the knowledgeable in the technical field under any; Do not breaking away 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

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 switch 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; Transistorized first end of this data switch 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 switch 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 and should show 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 so that the no-voltage position is accurate.

8. the driving method of an image element structure; It is characterized in that: this image element structure comprises a data switch transistor, a storage capacitors, a 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, and this driving transistors has one first end, one second end and a gate, and 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, and 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.