CN1553265A - Driving method and pixel structure for active matrix liquid-crystal displaying device - Google Patents
Driving method and pixel structure for active matrix liquid-crystal displaying device Download PDFInfo
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- CN1553265A CN1553265A CNA031378498A CN03137849A CN1553265A CN 1553265 A CN1553265 A CN 1553265A CN A031378498 A CNA031378498 A CN A031378498A CN 03137849 A CN03137849 A CN 03137849A CN 1553265 A CN1553265 A CN 1553265A
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- light emitting
- emitting diode
- organic light
- driving method
- active matrix
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Abstract
A liquid crystal display comprises a picture element, a data electrode and a scanning electrode as the picture element is equipped with an organic luminous diode. The driving method is as the follows, an organic luminous diode from the first current to the picture element is provided according to an image signal on data electrode and a scanning signal on scanning electrode in the first period of the first display period, the second current in counter phase to the first current is provided to organic luminous diode in the second period of display period in order to neutralize stored charge in internal of organic luminous diode.
Description
Technical field
The present invention is relevant for a kind of driving method of LCD, the driving method of relevant especially a kind of active matrix type liquid crystal display, utilization provides a backward current to Organic Light Emitting Diode, in coming and the inner charges accumulated of Organic Light Emitting Diode, with the rising of this Organic Light Emitting Diode voltage that eases up and increase its life-span.
Background technology
In general, in an active array type image display device, show an image by a large amount of pixels in the matrix, and, control the brightness of each pixel according to a monochrome information.
As shown in Figure 1, be an active matrix organic light-emitting diode (active matrix organiclight emitting diode, dot structure 10 AMOLED).When one scan electrode Scan enters a selected state, switching transistor T
1Conducting and when representing a data level of monochrome information to be applied to a data electrode DATA, memory capacitance C
SBe recharged or discharge, and driving transistors T
2Grid on voltage consistent with this data level.When this scan electrode SCAN enters a nonselection mode, switching transistor T
1End and driving transistors T
2Isolate with data electrode DATA electricity, and driving transistors T
2Voltage on the grid writes memory capacitance C by previous DATA
SStably be maintained the voltage of these data.By driving transistors T
2And the drive current I of the Organic Light Emitting Diode of flowing through (organic light emitting diode is hereinafter to be referred as OLED), according to driving transistors T
2Grid and the voltage between source electrode (Vgs) and producing, and OLED 20 produces brightness continuously according to the size of the drive current I that passes through.
That is to say that no matter its type of drive is current drives or driven, in the same display cycle (frame), the last suffered electric current of OLED is fixed, as shown in Figure 2.Yet this type of drive makes electric charge be accumulated in OLED inside to cause the OLED life-span to reduce.In addition, along with increase service time, the voltage V on the OLED
ORising significantly, (power consumption is P=I*V, therefore works as V
OIncrease in time, power consumption increases), as shown in Figure 3, curve C
1Expression OLED goes up voltage V
ORelation with service time.
Summary of the invention
In view of this, primary and foremost purpose of the present invention, in being and in the LCD of active type matrix formula, the inner charges accumulated of OLED is with this rising (being the rising of power consumption) that increases the life-span of OLED and slow down the voltage at OLED two ends.
For realizing this purpose, the invention provides a kind of driving method of LCD of active type matrix formula, can the neutralizer crystal display in the inner charges accumulated of OLED.In the driving method of the present invention, at first in the period 1 of a display cycle,, provide the OLED of one first electric current to this pixel according to picture signal on this data electrode and the one scan signal on this scan electrode.Then, in the second round of this display cycle, provide with anti-phase one second electric current of this first electric current to OLED so as in and the stored charge of OLED inside.
According to this purpose, the present invention also provides a kind of dot structure of active matrix type liquid crystal display, can in and the stored charge of OLED inside.Dot structure of the present invention comprises a switching transistor, and the one control end connects the one scan electrode and one first end connects a data electrode; One driving transistors, one control end connect one second end of this switching transistor, and one first end connects a power supply potential; One OLED, one anode connect second end of this driving transistors, and electrode is used in negative electrode connection altogether; One memory capacitance, the one end is connected to the control end of this driving transistors; And one drag down circuit, is connected between this OLED and one first power supply, in order to according to a control signal, drag down the current potential on the OLED anode, produce a backward current with this, in coming and electric charge accumulation in the OLED, wherein the current potential of first power supply is lower than the current potential on the negative electrode of OLED.
For above and other objects of the present invention, feature and advantage can be become apparent, a preferred embodiment cited below particularly, and conjunction with figs. are described in detail as follows.
Description of drawings
Fig. 1 is the synoptic diagram of known active matric Organic Light Emitting Diode.
Fig. 2 is the synoptic diagram of known driving method.
Fig. 3 is the voltage of known Organic Light Emitting Diode two ends of expression and the graph of a relation of service time.
Fig. 4 is the synoptic diagram of driving method of the present invention.
Fig. 5 is the synoptic diagram of dot structure of the present invention.
Fig. 6 is the synoptic diagram of driving method of the present invention.
Fig. 7 is the voltage of Organic Light Emitting Diode two ends and the graph of a relation of service time among expression the present invention.
Fig. 8 is the brightness of Organic Light Emitting Diode and the graph of a relation of service time among expression the present invention.
The drawing reference numeral explanation
DATA: data electrode SCAN: retouch and sweep electrode
T
1, T
11Switching transistor T
2, T
21: driving transistors
C
S, C
11: memory capacitance 20: Organic Light Emitting Diode
T
f: period 1 T
r: second round
I
f: forward current I
r: backward current
T
3: transistor S
1: control signal
Embodiment
As shown in Figure 4, be a kind of dot structure 100 of active matrix type liquid crystal display.In dot structure 100, switching transistor T
11Have control end connection one scan electrode SCAN and one first end and connect a data electrode DATA.One driving transistors T
21Have a control end and connect switching transistor T
11One second end and one first end connect a power supply potential V
DDOLED 20 has an anode and connects driving transistors T
21Second end and a negative electrode connect altogether with electrode (being not shown among the figure) an and memory capacitance C
11Have an end and be connected to driving transistors T
21Control end, wherein the current potential of common electrode is V
COMThough this dot structure of the present invention, in order to driving method of the present invention to be described, so it is not that other dot structure is also applicable in order to qualification the present invention.
With reference to figure 6 explanations driving method of the present invention.At first at the period 1 T of a display cycle frame N
fIn, according to picture signal on this data electrode DATA and the one scan signal on the scan electrode SCAN, provide one first electric current to OLED 20.That is to say switching transistor T
11According to the sweep signal conducting on the scan electrode SCAN, the picture signal on the data electrode DATA is to memory capacitance C
11Charge or discharge, driving transistors T simultaneously
21Voltage on the grid is adjusted and has a memory capacitance C
11In.Driving transistors T
21According to the control of its grid voltage, provide first electric current I
fTo OLED 20, and OLED20 is therefore luminous.Then, switching transistor T
11End, but driving transistors T
21According to being stored in memory capacitance C
11In voltage and continue conducting, so OLED 20 maintains identical brightness, wherein the frequency range of display cycle (frame) is about 10Hz to 10
6Hz.Yet this type of drive makes electric charge be accumulated in OLED 20 inside, cause 20 life-spans of OLED to reduce and OLED 20 2 ends on voltage V
ORise (power consumption increase).
Therefore, the present invention is then at T second round of display cycle frame N
rIn, second electric current I anti-phase with this first electric current is provided
rTo OLED 20, this second electric current I
rIn and the accumulation of the electric charge of OLED 20 inside, wherein period 1 T
fWith T second round
rTime ratio be approximately 1: 1 to 10
5: 1.
In this example, by drawing high the current potential V that is connected to the common electrode on OLED 20 negative electrodes
COMTo surpassing power supply potential V
DD, therefore, the current potential V of common electrode
COMBe higher than voltage Vr, so make voltage V on the OLED 20
OBecome a negative voltage, thereby produce second electric current I
rIn coming and OLED 20 inner charges accumulated.
Perhaps, as shown in Figure 5, the present invention utilizes a transistor T
3Drag down circuit as one, the one control end connects a control signal S
1, the one first end anode and one second end that connect OLED 20 connect one first power supply V
S, the first power supply V wherein
SCurrent potential to be lower than current potential V on OLED 20 negative electrodes
COMT second round at display cycle frame N
rIn, transistor T
3According to control signal S
1And conducting is moved the current potential Vr on the light emitting diode OLED anode to first power supply V
SCurrent potential (be lower than V
COM), this moment OLED 20 on voltage V
OTherefore become a negative voltage, just produce the backward current Ir OLED 20 that flows through, in coming and the inner charges accumulated of OLED20.Though the present invention uses aforementioned two kinds of modes to come to produce reverse current on OLED, in order to driving method of the present invention to be described, so it is not in order to limiting the present invention, and other can allow OLED produce the mode of reverse current, also applicable to driving method of the present invention.
Curve C among Fig. 7
1Represent in the known driving method relation of the voltage on service time and OLED two ends, curve C
2Represent in the driving method of the present invention the relation of the voltage of service time and OLED two ends.Hence one can see that, and driving method of the present invention can slow down the voltage of OLED two ends, along with the degree that rise service time, promptly can reduce the degree that power consumption increases.
In addition, as shown in Figure 8, curve C
3Expression does not add under the negative-phase sequence curent service time of OLED and the relation between brightness, curve C
4Expression period 1 T
f(forward current) and T second round
rThe time ratio of (backward current) is 10: 1 o'clock, the service time of OLED and the relation between brightness.Curve C
5Expression period 1 T
f(forward current) and T second round
rThe time ratio of (backward current) is 100: 1 o'clock, the service time of OLED and the relation between brightness.Curve C
6Expression period 1 T
f(forward current) and T second round
rThe time ratio of (backward current) is 500: 1 o'clock, the service time of OLED and the relation between brightness.As seen from the figure, under driving method of the present invention (having backward current), be about 2 times of the known driving method that do not add backward current the serviceable life of OLED (brightness is greater than 0.5).Therefore, driving method of the present invention can reduce known driving method effectively and cause the OLED life-span to reduce, and the voltage V on OLED two ends
ORise (power consumption increase).
In addition, in the driving method of the present invention, be not in each display cycle (frame), all to add the one-period that produces reverse current, after several display cycles of can also whenever being separated by, add a display cycle again with generation reverse current cycle.For instance, the 1st, 4,7 display cycles had the cycle that produces reverse current, and the 2nd, 3,5,6 display cycles did not then have the cycle that produces reverse current.
Though the present invention with preferred embodiment openly as above; right its is not in order to limit the present invention; any those skilled in the art; under the situation that does not break away from the spirit and scope of the present invention; can change and modification, so protection scope of the present invention is as the criterion with the claim institute restricted portion that is proposed.
Claims (18)
1. the driving method of an active matrix type liquid crystal display, wherein this LCD has at least one pixel, this pixel comprises a switching transistor and has that a control end connects the one scan electrode and one first end connects a data electrode, one driving transistors has one second end that a control end connects this switching transistor, one first end connects a power supply potential, one Organic Light Emitting Diode has an anode and connects second end of this driving transistors and a negative electrode and connect and use electrode altogether, and one memory capacitance have the control end that an end is connected to this driving transistors, this driving method comprises:
In the period 1 of a display cycle,, provide the Organic Light Emitting Diode of one first electric current to this pixel according to picture signal on this data electrode and the one scan signal on this scan electrode; And
In the second round of this display cycle, provide with anti-phase one second electric current of this first electric current to this Organic Light Emitting Diode, so that the stored charge of this Organic Light Emitting Diode inside that neutralizes.
2. the driving method of active matrix type liquid crystal display as claimed in claim 1, wherein second electric current produces by current potential to the current potential that is lower than on its negative electrode that drags down on this Organic Light Emitting Diode anode.
3. the driving method of active matrix type liquid crystal display as claimed in claim 1, wherein this second electric current produces by current potential to the power supply potential of drawing high on this Organic Light Emitting Diode negative electrode that is higher than on this driving transistors first end.
4. the driving method of active matrix type liquid crystal display as claimed in claim 1, wherein second electric current produces on the anode of this Organic Light Emitting Diode and negative electrode by applying a negative voltage.
5. the driving method of active matrix type liquid crystal display as claimed in claim 4, wherein the time ratio in this first and second cycle be 1: 1 to 10
5: 1.
6. the driving method of active matrix type liquid crystal display as claimed in claim 4, wherein the time ratio in this first and second cycle is 10: 1.
7. the driving method of an active matrix type liquid crystal display, wherein this LCD has at least one pixel, this pixel comprises a switching transistor and has that a control end connects the one scan electrode and one first end connects a data electrode, one driving transistors has one second end that a control end connects this switching transistor, one first end connects a power supply potential, one Organic Light Emitting Diode has an anode and connects second end of this driving transistors and a negative electrode and connect and use electrode altogether, and one memory capacitance have the control end that an end is connected to this driving transistors, this driving method comprises:
In the period 1 of one first display cycle,, provide the Organic Light Emitting Diode of one first electric current to this pixel according to one first picture signal on this data electrode and one first sweep signal on this scan electrode;
In the second round of this first display cycle, provide with the anti-phase backward current of this first electric current to this Organic Light Emitting Diode, so that the stored charge of this Organic Light Emitting Diode inside that neutralizes;
In one second display cycle,, provide the Organic Light Emitting Diode of one second electric current to this pixel according to one second picture signal on this data electrode and one second sweep signal on this scan electrode;
In the period 1 of one the 3rd display cycle,, provide the Organic Light Emitting Diode of one the 3rd electric current to this pixel according to one the 3rd picture signal on this data electrode and one the 3rd sweep signal on this scan electrode; And
In the second round of the 3rd display cycle, provide with anti-phase this backward current of the 3rd electric current to this Organic Light Emitting Diode, so that the stored charge of this Organic Light Emitting Diode inside that neutralizes.
8. the driving method of active matrix type liquid crystal display as claimed in claim 7, wherein this backward current produces by current potential to the current potential that is lower than on its negative electrode that drags down on this Organic Light Emitting Diode anode.
9. the driving method of active matrix type liquid crystal display as claimed in claim 7, wherein this backward current produces by current potential to the power supply potential of drawing high on this Organic Light Emitting Diode negative electrode that is higher than on this driving transistors first end.
10. the driving method of active matrix type liquid crystal display as claimed in claim 7, wherein backward current produces at this Organic Light Emitting Diode by applying a revers voltage.
11. the driving method of active matrix type liquid crystal display as claimed in claim 4, wherein the time ratio in this first and second cycle be 1: 1 to 10
5: 1.
12. the driving method of active matrix type liquid crystal display as claimed in claim 11, wherein the time ratio in this first and second cycle is 10: 1.
13. the driving method of an active matrix type liquid crystal display, wherein this LCD comprises at least one pixel, a data electrode, one scan electrode and uses electrode altogether, and this pixel has an Organic Light Emitting Diode, and this driving method comprises:
When a display cycle,, provide the Organic Light Emitting Diode of one first electric current to this pixel according to picture signal on this data electrode and the one scan signal on this scan electrode; And
Before next display cycle, provide one second electric current to this Organic Light Emitting Diode, wherein this second electric current and first electric current are anti-phase.
14. the driving method of active matrix type liquid crystal display as claimed in claim 13, wherein this Organic Light Emitting Diode has an anode and a negative electrode, and this second electric current produces by current potential to the current potential of drawing high on this Organic Light Emitting Diode negative electrode that is higher than on its anode.
15. the driving method of active matrix type liquid crystal display as claimed in claim 13, wherein this Organic Light Emitting Diode has an anode and a negative electrode, and this second electric current produces by current potential to the current potential that is lower than on its negative electrode that drags down on this Organic Light Emitting Diode anode.
16. the driving method of active matrix type liquid crystal display as claimed in claim 13, wherein this Organic Light Emitting Diode has an anode and a negative electrode, and this second electric current produces on the anode of this Organic Light Emitting Diode and negative electrode by applying a revers voltage.
17. the dot structure of an active matrix type liquid crystal display comprises:
One switching transistor, the one control end connects the one scan electrode and one first end connects a data electrode;
One driving transistors, one control end connect one second end of this switching transistor, and one first end connects a power supply potential;
One Organic Light Emitting Diode, one anode connect second end of this driving transistors, and electrode is used in negative electrode connection altogether;
One memory capacitance, the one end is connected to the control end of this driving transistors; And
One drags down circuit, be connected between this Organic Light Emitting Diode and one first power supply, in order to according to a control signal, drag down the current potential on this Organic Light Emitting Diode anode, produce a backward current with this, the electric charge accumulation in this Organic Light Emitting Diode that neutralizes, wherein the current potential of this first power supply is lower than the current potential on the negative electrode of this Organic Light Emitting Diode.
18. the dot structure of active matrix type liquid crystal display as claimed in claim 17, wherein this to drag down circuit be a transistor, be coupled this control signal, one first end of one control end connects the anode of this Organic Light Emitting Diode, and one second end connects this first power supply.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031378498A CN1308756C (en) | 2003-05-26 | 2003-05-26 | Driving method and pixel structure for active matrix liquid-crystal displaying device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031378498A CN1308756C (en) | 2003-05-26 | 2003-05-26 | Driving method and pixel structure for active matrix liquid-crystal displaying device |
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| CN1553265A true CN1553265A (en) | 2004-12-08 |
| CN1308756C CN1308756C (en) | 2007-04-04 |
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Cited By (1)
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|---|---|---|---|---|
| CN111091781A (en) * | 2018-10-23 | 2020-05-01 | 联咏科技股份有限公司 | Display device and operation method of display panel thereof |
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| JPH1020282A (en) * | 1996-07-04 | 1998-01-23 | Citizen Watch Co Ltd | Driving method of liquid crystal display device |
| JP2001209028A (en) * | 2000-01-27 | 2001-08-03 | Matsushita Electric Ind Co Ltd | Driving device of liquid crystal display panel |
| JP2002040993A (en) * | 2000-07-21 | 2002-02-08 | Matsushita Electric Ind Co Ltd | Driving method for display device, and display device |
| JP2002268611A (en) * | 2001-03-12 | 2002-09-20 | Toshiba Corp | Counter potential generating circuit, planar display device and method for driving the same device |
| JP2002304147A (en) * | 2001-04-06 | 2002-10-18 | Sharp Corp | Method for driving image display, device for driving image display and image display |
| KR100433216B1 (en) * | 2001-11-06 | 2004-05-27 | 엘지.필립스 엘시디 주식회사 | Apparatus and method of driving electro luminescence panel |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111091781A (en) * | 2018-10-23 | 2020-05-01 | 联咏科技股份有限公司 | Display device and operation method of display panel thereof |
| US11062653B2 (en) | 2018-10-23 | 2021-07-13 | Novatek Microelectronics Corp. | Display apparatus and operation method for display panel thereof |
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| CN1308756C (en) | 2007-04-04 |
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Granted publication date: 20070404 |