CN101183199A - LCD device removing ghost - Google Patents
LCD device removing ghost Download PDFInfo
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- CN101183199A CN101183199A CNA2007101803549A CN200710180354A CN101183199A CN 101183199 A CN101183199 A CN 101183199A CN A2007101803549 A CNA2007101803549 A CN A2007101803549A CN 200710180354 A CN200710180354 A CN 200710180354A CN 101183199 A CN101183199 A CN 101183199A
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Abstract
The present invention discloses a liquid crystal display for eliminating remnant shadows, which comprises a source cathode driver, a grid driver and a plurality of pixel units. Each pixel unit comprises a switch unit, a pixel electrode, a first electrode, a second electrode, a liquid crystal capacitor and a storage capacitor. The switch unit is used to communicate a pixel data voltage when receiving a driving signal voltage. The first electrode is used to provide a first signal voltage. The second electrode is used to provide a second signal voltage. The first pole of the liquid crystal display is electrically connected with the first electrode; a second pole is electrically connected with the pixel electrode; so the liquid crystal molecules in the liquid crystal display can be driven according to the pixel data voltage and the first signal voltage. The first pole of the storage capacitor is connected with the pixel electrode; the second pole is electrically connected with the second electrode; wherein, the quasi bit of the second signal voltage is bigger than the quasi bit of the first signal voltage.
Description
[technical field]
The present invention relates to a kind of LCD, refer in particular to a kind of LCD of improving power-off ghost shadow.
[background technology]
Function advanced person's display gradually becomes the valuable feature of consumption electronic product now, and wherein LCD has become the display that various electronic equipments such as mobile phone, PDA(Personal Digital Assistant), digital camera, computer screen or the widespread use of notebook computer screen institute have the high-res color/graphics gradually.
Yet,,,, therefore have the generation of ghost phenomena so the electric charge of display frame before remains within the liquid crystal capacitance of display panels because discharge is not enough sometimes because the leakage current of electric crystal is very little when LCD during at powered-down.Problem for fear of ghost, prior art (announces the 6th as United States Patent (USP), 476, No. 590) disclose after shutdown starts, time schedule controller is sent a specific voltage data signal, makes source electrode driver to produce specific picture according to this specific voltage data signal, for example black picture or white picture, but such design can increase the complexity of system design, therefore still remains further to be improved.
[summary of the invention]
In view of this, purpose of the present invention provides a kind of LCD of avoiding ghost phenomena, makes LCD when powered-down, and picture can present uniformly, to solve the problem of above-mentioned prior art.
According to a purpose of the present invention, the invention provides a kind of LCD, comprise one source pole driver, a gate drivers and a plurality of pixel cell.Source electrode driver is used for producing a pixel data voltage.Gate drivers is used for producing a drive signal voltage.Each pixel cell comprises a switch element, a pixel electrode, one first electrode, one second electrode, a liquid crystal capacitance and a storage capacitors.Switch element is used for when receiving this drive signal voltage, this pixel data voltage of conducting.Pixel electrode is electrically connected at switch element.First electrode is used to provide first signal voltage.Second electrode is used to provide secondary signal voltage.Liquid crystal capacitance has first utmost point and second utmost point, and first utmost point of liquid crystal capacitance is electrically connected at this first electrode, and second utmost point of liquid crystal capacitance is electrically connected at pixel electrode, is used for driving liquid crystal molecule in it according to the pixel data voltage and first signal voltage.Storage capacitors has first utmost point and second utmost point, and first utmost point of storage capacitors is electrically connected at this pixel electrode, and second utmost point of storage capacitors is electrically connected at second electrode, and wherein the accurate position of secondary signal voltage is greater than the accurate position of first signal voltage.
According to one embodiment of the invention, the accurate position of aforementioned secondary signal voltage equals the accurate position of the maximum output voltage of source electrode driver.
The present invention provides a kind of LCD in addition, comprises one source pole driver, a gate drivers and a plurality of pixel cell.Source electrode driver is used for producing a pixel data voltage.Gate drivers is used for producing a drive signal voltage.Each pixel cell comprises a switch element, a pixel electrode, one first electrode, one second electrode, a liquid crystal capacitance, one first storage capacitors and one second storage capacitors.Switch element is used for when receiving this drive signal voltage, this pixel data voltage of conducting.Pixel electrode is electrically connected at switch element.First electrode is used to provide first signal voltage.Second electrode is used to provide secondary signal voltage.Liquid crystal capacitance has first utmost point and second utmost point, and wherein first utmost point is electrically connected at first electrode, and second utmost point is electrically connected at pixel electrode, is used for driving liquid crystal molecule in it according to the pixel data voltage and first signal voltage.First storage capacitors has first utmost point and second utmost point, and wherein first utmost point of first storage capacitors is electrically connected at pixel electrode, and second utmost point of first storage capacitors is electrically connected at first electrode.Second storage capacitors has first utmost point and second utmost point, and first utmost point of second storage capacitors is electrically connected at this pixel electrode, and second utmost point of second storage capacitors is electrically connected at second electrode, and wherein the accurate position of secondary signal voltage is greater than the accurate position of first signal voltage.
For technology contents of the present invention, purpose and advantage can be become apparent, preferred embodiment cited below particularly also cooperates appended graphicly, is described in detail below:
[description of drawings]
Fig. 1 is the functional block diagram of LCD of the present invention.
Fig. 2 is the equivalent circuit diagram of pixel cell of the present invention.
Fig. 3 A is that the first electrode COM1 provides the first signal voltage V
COM1Provide secondary signal voltage V with the second electrode COM2
COM2When being all 3V, the voltage quasi position of pixel electrode changes before and after the shutdown.
Fig. 3 B is that the first electrode COM1 provides the first signal voltage V
COM1During for 3V and the second electrode COM2 secondary signal voltage V is provided
COM2During for 8.5V, the voltage quasi position of pixel electrode changes before and after the shutdown.
Fig. 4 is the equivalent circuit diagram of the pixel cell of second embodiment of the invention.
[embodiment]
See also Fig. 1, Fig. 1 is the functional block diagram of LCD of the present invention.LCD 10 comprises power supply unit 12, time schedule controller 14, multiple source driver 16, a plurality of gate drivers 18, first voltage generator 25, second voltage generator 27 and display panels 20.Display panels 20 comprises a plurality of pixel cells 28.Power supply unit 12 is used for supplying LCD 10 interior all circuit and comprises time schedule controller 14, multiple source driver 16 and a plurality of gate drivers 18 necessary operations voltage Vsup.For making drawing clear, in Fig. 1, only show the annexation of power supply unit 12 and multiple source driver 16.When the clock signal that produces when time schedule controller 14 is sent to a plurality of gate drivers 18, a plurality of gate drivers 18 can produce sweep signal and be sent to display panels 20 via sweep trace 26, at the same time, 14 of time schedule controllers can send clock signal to source electrode driver 16, and source electrode driver 16 will receive the digital data signal voltage that time schedule controller 14 is transmitted according to clock signal.When the pixel cell 28 of display panels 20 receives sweep signal, the digital data signal voltage show image that will send out via data line 24 according to source electrode driver 16.First voltage generator 25 is used to provide one first signal voltage V
COM1 Second voltage generator 27 is used to provide a secondary signal voltage V
COM2This secondary signal voltage V
COM2Accurate position greater than this first signal voltage V
COM1Accurate position.
See also Fig. 2, Fig. 2 is the equivalent circuit diagram of the pixel cell of first embodiment of the invention.Form pixel cell 28 between multi-strip scanning line (gateline) 26 and many data lines (data line) 24 interlock, be formed with liquid crystal capacitance C in each pixel cell 28
LCAnd storage capacitors C
ST, liquid crystal capacitance C
LCFormed by including a liquid crystal layer between two electrodes.Liquid crystal capacitance C
LCA polar system be coupled to pixel electrode 30, to be connected (switch element SW system realized with the film liquid crystal) in the present embodiment with switch element SW, another utmost point then is connected with the first electrode COM1.Storage capacitors C
STBe used for reducing the interference of outside noise signal, and storage capacitors C
STA utmost point be coupled to pixel electrode 30, to be connected with switch element SW, another utmost point links to each other with the second electrode COM2.The first electrode COM1 is coupled to first voltage generator 25, to be used to provide the first signal voltage V
COM1The second electrode COM2 is coupled to second voltage generator 27, to be used to provide secondary signal voltage V
COM2
See also Fig. 3 A and Fig. 3 B, Fig. 3 A is that the first electrode COM1 provides the first signal voltage V
COM1Provide secondary signal voltage V with the second electrode COM2
COM2When being all 3V, the voltage quasi position of pixel electrode 30 changes before and after the shutdown, and Fig. 3 B is that the first electrode COM1 provides the first signal voltage V
COM1During for 3V and the second electrode COM2 secondary signal voltage V is provided
COM2During for 8.5V, the voltage quasi position of pixel electrode changes before and after the shutdown.The reason that takes place owing to ghost phenomena is that LCD is when powered-down, because the leakage current of switch element SW is very little, so the electric charge of display frame before also remains in the liquid crystal capacitance C of display panels 20
LCWithin, that is to say that the current potential of pixel electrode 30 is not reduced to 0V.From Fig. 3 A, when the first electrode COM1 provides the first signal voltage V
COM1Provide secondary signal voltage V with the second electrode COM2
COM2When being all 3V, after the shutdown, the first signal voltage V
COM1With secondary signal voltage V
COM2Be back to 0V, the accurate position of the maximum voltage of pixel electrode 30 Vmax can be because capacitive coupling (coupling) effect drops to 4V.Utilize the leakage current discharge of switch element SW to drop to 0V and need 10 seconds approximately, that is to say that ghost phenomena is kept 10 seconds time approximately with 4V with pixel electrode 30.But in the present invention, see it, when the first electrode COM1 provides the first signal voltage V from Fig. 3 B
COM1During for 3V and the second electrode COM2 secondary signal voltage V is provided
COM2During for 8.5V, after the shutdown, the first signal voltage V
COM1With secondary signal voltage V
COM2Be back to 0V, but the accurate position of the maximum voltage of pixel electrode 30 Vmax can be because capacitive coupling (coupling) effect drops to 1.5V.Utilize the leakage current discharge of switch element SW to drop to 0V and need 1 second approximately, that is to say that ghost phenomena can be improved to only 1 second time with 1.5V with pixel electrode 30.Change speech, preferred embodiment of the present invention ties up to shutdown moment, makes the accurate position of the maximum voltage Vmax of pixel electrode 30 can level off to 0V, in the hope of reducing the time of leakage current discharge, reduces the puzzlement of ghost phenomena.Because V
COM1, V
COM2Effect (charge sharing) is shared because of electric charge in the shutdown back can make the pressure drop (voltage drop) of pixel electrode 30 generations be (C
ST* V
COM2+ C
LC* V
COM1)/(C
ST+ C
LC).So when design, the pressure drop that pixel electrode 30 produces when desiring to make shutdown meets the accurate position of maximum voltage Vmax, then (C
ST* V
COM2+ C
LC* V
COM1)/(C
ST+ C
LCSo)=Vmax is V
COM2=(Vmax * (C
ST+ C
LC)-C
LC* V
COM1)/C
ST
For instance, if Vmax=7V, V
COM1=3V, C
ST: C
LC=1: 1, then can select V
COM2=11V is so that the pressure drop that produces of pixel electrode 30 of when shutdown meets the accurate position of maximum voltage Vmax.Yet technology contents of the present invention is as limit, secondary signal voltage V
COM2Accurate position as long as greater than this first signal voltage V
COM1Accurate position all should belong to category of the present invention.On actual design, C
ST/ C
LC=0.5 ~ 2, V
COM2Design between Vmax ~ 2Vmax, has preferable effect greatly.
See also Fig. 4, Fig. 4 is the equivalent circuit diagram of the pixel cell of the second embodiment of the present invention.Form pixel cell 58 between multi-strip scanning line (gateline) 26 and many data lines (data line) 24 interlock, be formed with liquid crystal capacitance C in each pixel cell 58
LCAnd the first storage capacitors C
ST1And the second storage capacitors C
ST2Liquid crystal capacitance C
LCFormed by including a liquid crystal layer between two electrodes.Liquid crystal capacitance C
LCA polar system be coupled to pixel electrode 30, to be connected (switch element SW system realized with the film liquid crystal) in the present embodiment with switch element SW, another utmost point then is connected with the first electrode COM1, the first storage capacitors C
ST1The one utmost point is coupled to pixel electrode 30, and to be connected with switch element SW, another utmost point links to each other with the first electrode COM1.The second storage capacitors C
ST2A utmost point be coupled to pixel electrode 30, to be connected with switch element SW, another utmost point links to each other with the second electrode COM2.The first electrode COM1 is coupled to first voltage generator 25, to be used to provide the first signal voltage V
COM1The second electrode COM2 is coupled to second voltage generator 27, to be used to provide secondary signal voltage V
COM2
In the present embodiment, because V
COM1, V
COM2Effect (charge sharing) is shared because of electric charge in the shutdown back can make the pressure drop (voltage drop) of pixel electrode 30 generations be (C
ST2* V
COM2+ (C
ST1+ C
LC) * V
COM1)/(C
ST1+ C
ST2+ C
LC).So when design, the pressure drop that pixel electrode 30 produces when desiring to make shutdown meets the accurate position of maximum voltage Vmax, then (C
ST2* V
COM2+ (C
ST1+ C
LC) * V
COM1)/(C
ST1+ C
ST2+ C
LC)=VmaxV
COM2=(Vmax * (C
ST1+ C
ST2+ C
LC)-(C
ST1+ C
LC) * V
COM1)/C
ST2
For instance, if Vmax=7V, V
COM1=3V, C
ST1: C
ST2: C
LC=1: 1: 1, then can select V
COM2=15V is so that the pressure drop that produces of pixel electrode 30 of when shutdown meets the accurate position of maximum voltage Vmax.Yet technology contents of the present invention is as limit, secondary signal voltage V
COM2Accurate position as long as greater than the first signal voltage V
COM1Accurate position all should belong to category of the present invention.In fact the second storage capacitors C
ST2Capacitance may only account for (C
ST1+ C
ST2+ C
LC) size less than 1/3, so can be with V
COM2Be increased to the accurate position of ceiling voltage of the gate drivers that approximates panel greatly, preferable effect is promptly arranged.
Compared to prior art, the present invention system is couple to first signal voltage with liquid crystal capacitance, and storage capacitors is couple to secondary signal voltage, and the accurate position of secondary signal voltage is greater than the accurate position of first signal voltage.Voltage with pixel electrode after shutdown can be reduced to lower accurate position via the mode that is coupled.Can shorten the back discharge time of shutting down thus, reduce the power-off ghost shadow time.
Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; any general skill person who has the knack of the technical field of the invention; without departing from the spirit and scope of the present invention; when can 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 (5)
1. LCD comprises:
The one source pole driver is used for producing a pixel data voltage;
One gate drivers is used for producing a drive signal voltage; And
A plurality of pixel cells, each pixel cell comprises:
One switch element is used for when receiving this drive signal voltage this pixel data voltage of conducting;
One pixel electrode is electrically connected at this switch element;
One first electrode is used to provide one first signal voltage;
One second electrode is used to provide a secondary signal voltage;
One liquid crystal capacitance, have one first utmost point and one second utmost point, first utmost point of this liquid crystal capacitance is electrically connected at this first electrode, and second utmost point of this liquid crystal capacitance is electrically connected at this pixel electrode, is used for driving liquid crystal molecule in it according to this pixel data voltage and this first signal voltage; And
One storage capacitors has one first utmost point and one second utmost point, and first utmost point of this storage capacitors is electrically connected at this pixel electrode, and second utmost point of this storage capacitors is electrically connected at this second electrode.
2. LCD according to claim 1 is characterized in that, the accurate position of this secondary signal voltage is greater than the accurate position of this first signal voltage.
3. LCD according to claim 2, it is characterized in that the voltage quasi position scope of the accurate position of this secondary signal voltage equals between the twice of maximum accurate position of pixel data voltage of the maximum accurate position of pixel data voltage of this source electrode driver output and the output of this source electrode driver.
4. LCD comprises:
The one source pole driver is used for producing a pixel data voltage;
One gate drivers is used for producing a drive signal voltage; And
A plurality of pixel cells, each pixel cell comprises:
One switch element is used for when receiving this drive signal voltage this pixel data voltage of conducting;
One pixel electrode is electrically connected at this switch element;
One first electrode is used to provide one first signal voltage;
One second electrode is used to provide a secondary signal voltage;
One liquid crystal capacitance, have one first utmost point and one second utmost point, first utmost point of this liquid crystal capacitance is electrically connected at this first electrode, and second utmost point of this liquid crystal capacitance is electrically connected at this pixel electrode, is used for driving liquid crystal molecule in it according to this pixel data voltage and this first signal voltage;
One first storage capacitors has one first utmost point and one second utmost point, and first utmost point of this first storage capacitors is electrically connected at this first electrode, and second utmost point of this first storage capacitors is electrically connected at this pixel electrode;
And
One second storage capacitors has one first utmost point and one second utmost point, and first utmost point of this second storage capacitors is electrically connected at this pixel electrode, and second utmost point of this second storage capacitors is electrically connected at this second electrode.
5. LCD according to claim 4 is characterized in that, the accurate position of this secondary signal voltage is greater than the accurate position of this first signal voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007101803549A CN101183199A (en) | 2007-10-16 | 2007-10-16 | LCD device removing ghost |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007101803549A CN101183199A (en) | 2007-10-16 | 2007-10-16 | LCD device removing ghost |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101183199A true CN101183199A (en) | 2008-05-21 |
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ID=39448525
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2007101803549A Pending CN101183199A (en) | 2007-10-16 | 2007-10-16 | LCD device removing ghost |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101183199A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101710478B (en) * | 2009-11-25 | 2012-03-28 | 友达光电股份有限公司 | Planer display, shift register and method for eliminating shutdown ghosting image |
| CN103809317A (en) * | 2013-10-23 | 2014-05-21 | 友达光电股份有限公司 | Display panel |
| CN109192164A (en) * | 2018-10-10 | 2019-01-11 | 惠科股份有限公司 | Display device and its method for eliminating shutdown ghosting image |
-
2007
- 2007-10-16 CN CNA2007101803549A patent/CN101183199A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101710478B (en) * | 2009-11-25 | 2012-03-28 | 友达光电股份有限公司 | Planer display, shift register and method for eliminating shutdown ghosting image |
| CN103809317A (en) * | 2013-10-23 | 2014-05-21 | 友达光电股份有限公司 | Display panel |
| CN103809317B (en) * | 2013-10-23 | 2016-08-17 | 友达光电股份有限公司 | Display panel |
| US9581850B2 (en) | 2013-10-23 | 2017-02-28 | Au Optronics Corp. | Display panel |
| CN109192164A (en) * | 2018-10-10 | 2019-01-11 | 惠科股份有限公司 | Display device and its method for eliminating shutdown ghosting image |
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