CN101727837B - Liquid crystal display and driving method thereof - Google Patents

Abstract

The invention discloses a liquid crystal display and a driving method thereof. A pixel of the liquid crystal display comprises a first pixel capacitor, a second pixel capacitor, a first transistor and a second transistor. The first and second ends of the first pixel capacitor are coupled to the second transistor and the common voltage respectively; the first and second ends of the second pixel capacitor are coupled to the second transistor and the common voltage respectively; and the coupled cross-over voltage of the first pixel capacitor can be different from the coupled cross-over voltage of the second pixel capacitor by modulating the common voltage, so the colour offset phenomena can be improved.

Description

Liquid Crystal Display And Method For Driving

Technical field

The present invention relates to a kind of LCD, and relate in particular to a kind of halftone technique of LCD.

Background technology

For LCD wide viewing angle technology, at present the most universal is perpendicular alignmnet pattern (Vertically Aligned Mode, VA pattern) colour liquid crystal display device.But when watching perpendicular alignmnet pattern color LCD with the angle of inclination, can see the phenomenon that Asian skin has inclined to one side indigo plant or turns white.This phenomenon is called as colour cast (Color Wash-Out).Consult Figure 1A, 1B, it shows the transmissivity-voltage curve of perpendicular alignmnet pattern color LCD, and wherein the longitudinal axis is that transmissivity, transverse axis are for applying voltage.When voltage increased, facing angular curve 102 transmissivities also increased, and is a monotonic quantity, and anorthopia angular curve 104 transmissivities then have buckling phenomenon, made that transmissivity is identical for different gray level current potentials.This is the peculiar phenomenon of perpendicular alignmnet pattern color LCD, also is the reason that causes colour cast.In order to address this problem; The people such as H.Yoshidaet of Fujitsu (Fujitsu Display Technologies Corporation) have delivered the method for improving; This method is a pixel cell to be divided into two kinds of different gamma characteristic curves form two kinds of zones that comprise different transmissivity-voltage characteristics; Improve to carry out colour mixture, it is called as shadow tone (Half-Tone) technology.The curve 106 of Figure 1B is for having the transmissivity-voltage curve of low critical voltage, and curve 108 is for having the transmissivity-voltage curve of high critical voltage, and both mix the transmissivity-voltage curve 110 that forms a dullness, have eliminated color offset phenomenon.

See also Fig. 2 A and Fig. 2 B.Halftone technique has two types at present, CC type and TT type.Fig. 2 A shows the CC type, and Fig. 2 B shows the TT type.Basic principle is exactly that pixel cell originally is divided into two zones, is respectively first and second sub-pixel, makes them comprise different gamma characteristic curves, reaches above-mentioned halftone technique, eliminates the phenomenon of colour cast.Fig. 2 C is depicted as the gamma characteristic curve of CC type, and Fig. 2 D is depicted as the gamma characteristic curve of TT type.With Fig. 2 C is example, and under gray-scale voltage, the mixing gamma characteristic curve that pixel cell appeared is the first sub-pixel gamma characteristic curve and the second sub-pixel gamma characteristic curve sum.

Shown in Fig. 2 A, pixel cell is divided into two zones, utilize the mode of capacitance partial pressure to produce 214 two different an ancient woman's ornament sign indicating number family curves of sub-pixel electric capacity 208 and sub-pixel electric capacity.Wherein the current potential of sub-pixel electric capacity 208 is write direct via transistor 202 by data line.The current potential of sub-pixel electric capacity 214 is by the MM CAP 210 dividing potential drops afterwards decision of data line via series connection; In other words; Sub-pixel electric capacity 214 determines for the mode of its current potential of floating via coupling; This can be because mend the skew catch electric charge and cause sub-pixel electric capacity 214 current potentials in the operation of panel, this can cause that reliability reduces, picture is inhomogeneous and problem such as image residue.

Consult Fig. 2 B, pixel cell is divided into two zones, utilize transistor 218 directly two different gamma characteristic curves to be offered sub-pixel electric capacity 226 and sub-pixel electric capacity 228 by system with 220 and two sweep traces or two data lines.This is a method the most directly, but can make the aperture like this than reduce and make circuit system complicated (needing to increase other one group of gamma characteristic curve), the logic gate that causes doubling simultaneously drives or data line drives, and makes various shortcoming such as electrical source consumption increase.

Summary of the invention

The present invention provides a kind of LCD, is used to improve color offset phenomenon.

The present invention provides a kind of driving method of LCD, through the modulation common electric voltage, makes first pixel capacitance and second pixel capacitance have different coupling voltage, thereby improves color offset phenomenon.

According to one side, the present invention provides a kind of LCD, comprising: substrate, relative substrate, bias electrode, public electrode, first pixel electrode, second pixel electrode and shared electrode.Said relative substrate is corresponding to substrate.Bias electrode and public electrode are disposed on the substrate.First pixel electrode and bias electrode, public electrode partly overlap, and form respectively to have capacitance C _St1First MM CAP with have a capacitance C _St3The 3rd MM CAP.Second pixel electrode and bias electrode, public electrode partly overlap, and form respectively to have capacitance C _St2Second MM CAP with have a capacitance C _St4The 4th MM CAP.Shared electrode is disposed on the relative substrate, and overlaps with first pixel electrode, second pixel electrode respectively, forms to have capacitance C _Lc1First pixel capacitance with have a capacitance C _1c2Second pixel capacitance.Wherein,

$\frac{C_{\mathrm{st}3}+C_{\mathrm{lc}1}}{{\mathrm{<figure-callout\; id="1"\; label="C\; st"\; filenames="H2008101667981E00032.png,H2008101667981E00061.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{st}}+C_{\mathrm{st}3}+{\mathrm{<figure-callout\; id="1"\; label="C\; lc"\; filenames="H2008101667981E00032.png,H2008101667981E00061.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{lc}}}\&NotEqual;\frac{{\mathrm{<figure-callout\; id="4"\; label="C\; st"\; filenames="H2008101667981E00042.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{st}}+C_{\mathrm{lc}2}}{C_{\mathrm{st}2}+{\mathrm{<figure-callout\; id="4"\; label="C\; st"\; filenames="H2008101667981E00042.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{st}}+C_{\mathrm{lc}2}}.$

According to a further aspect in the invention, the present invention provides a kind of driving method that is used to drive above-mentioned LCD, comprising: in the period 1, common electric voltage is provided to shared electrode, and the modulation common electric voltage.In addition, through first end of first pixel capacitance coupling the first transistor, and first end through second pixel capacitance coupling transistor seconds.In addition, coupled voltages between first end of first end of the first transistor and transistor seconds.

The present invention utilizes the technology of modulation common electric voltage, makes first pixel capacitance different with the coupled voltages of second pixel capacitance, therefore can improve color offset phenomenon.

Description of drawings

Figure 1A is the transmissivity-voltage curve of perpendicular alignmnet pattern color LCD;

Figure 1B is the transmissivity-voltage curve that comprises the perpendicular alignmnet pattern color LCD of two groups of gamma curve;

Fig. 2 A is traditional CC type pixel cell;

Fig. 2 B is a traditional T T type pixel cell;

Fig. 2 C is the gamma characteristic curve map of traditional CC type pixel cell;

Fig. 2 D is the single gamma characteristic curve map of traditional T T type pixel;

Fig. 3 A is a kind of image element circuit figure according to the LCD of first embodiment of the invention;

Fig. 3 B is according to first embodiment of the invention modulation common electric voltage V _ComThe waveform synoptic diagram;

Fig. 3 C is the process flow diagram according to a kind of image element driving method of first embodiment of the invention;

Fig. 3 D is the common electric voltage V according to the even frame of first embodiment of the invention _Com, coupled voltages Δ V _P1With Δ V _P2The waveform synoptic diagram.

Fig. 3 E is the common electric voltage V according to the odd-numbered frame of first embodiment of the invention _Com, coupled voltages Δ V _P1With Δ V _P2The waveform synoptic diagram;

Fig. 4 A is the vertical view according to first kind of dot structure of first embodiment of the invention;

Fig. 4 B is along the T among Fig. 4 A ₁To T ₁' sectional view;

Fig. 4 C is the vertical view according to second kind of dot structure of first embodiment of the invention;

Fig. 4 D is along the T among Fig. 4 C ₁To T ₁' sectional view;

Fig. 5 is a kind of image element circuit figure according to the LCD of second embodiment of the invention;

Fig. 6 A is the vertical view according to a kind of dot structure of second embodiment of the invention;

Fig. 6 B is along the T among Fig. 6 A ₂To T ₂' sectional view;

Fig. 7 is a kind of image element circuit figure according to the LCD of third embodiment of the invention;

Fig. 8 A is a kind of image element circuit figure according to the LCD of fourth embodiment of the invention;

Fig. 8 B is the another kind of image element circuit figure according to the LCD of fourth embodiment of the invention.

[primary clustering symbol description]

102,104,106,108,110: transmissivity-voltage curve

441,442: pixel electrode

10,11,12,13,14: pixel

21,22,208,214,226,228: sub-pixel electric capacity

31,32,202,218,220: transistor

41,42,43,44,204,210,230,232: MM CAP

51,52: sub-pixel

61,62: stray capacitance

410,470: substrate

411,471: down/upper glass

412,472: polaroid

420: bias electrode

430: dielectric layer

450: liquid crystal layer

460: shared electrode

480: public electrode

491,492: the subregion of pixel electrode

SL: sweep trace

DL: data line

BL: bias line

V _Com1, V _Com2: the voltage reference current potential of common electric voltage

V _Com: common electric voltage

V ₀～V ₇: gray-scale voltage

Δ V _P1, Δ V _P2: cross-pressure

Δ V _Com: the modulation voltage of common electric voltage

S301～S304: each step of image element driving method

Embodiment

In order to make above-mentioned feature and advantage of the present invention clearer, be elaborated below in conjunction with several embodiment shown in the drawings.

First embodiment

Fig. 3 A is a kind of image element circuit figure according to the LCD of first embodiment of the invention.Pixel 10 comprises pixel capacitance 21,22, transistor 31,32 and MM CAP 41,42.Second end of pixel capacitance 21,22 couples shared electrode, and shared electrode couples common electric voltage V _ComFirst end of transistor 31, second end and gate terminal couple first end, data line DL and the sweep trace SL of pixel capacitance 21 respectively, and have stray capacitance 61 between first end of transistor 31 and the gate terminal.First end of transistor 32, second end and gate terminal couple first end, data line DL and the sweep trace SL of pixel capacitance 22 respectively, and have stray capacitance 62 between first end of transistor 32 and the gate terminal.

Then, first end of MM CAP 41 and second end couple first end and the bias line BL of pixel capacitance 21 respectively.First end of MM CAP 42 and second end couple first end and the bias line BL of pixel capacitance 22 respectively.In the present embodiment, bias line BL is the sweep trace that the previous column pixel of pixel 10 is coupled, but bias line BL also can be second bias electrode in other embodiments.

Fig. 3 B is the modulation common electric voltage V according to first embodiment of the invention _ComThe waveform synoptic diagram.Pass through modulation common electric voltage V in the present embodiment _Com, so that the cross-pressure Δ V that 21 of pixel capacitances are coupled out _P1(being first end of pixel capacitance 21 and the pressure reduction between second end) is different from the cross-pressure Δ V that 22 of pixel capacitances are coupled out _P2(being first end of pixel capacitance 22 and the pressure reduction between second end).Wherein, common electric voltage V _ComTwo voltage reference current potentials are for example arranged, be respectively high reference potential V _Com1With low reference potential V _Com2

Above-mentioned modulation common electric voltage V _Com, for example can be with common electric voltage by high reference potential V _Com1Change into low reference potential V _Com2, or with common electric voltage V _ComBy low reference potential V _Com2Change into high reference potential V _Com1In more detail, as cross-pressure Δ V _P1With Δ V _P2With respect to common electric voltage V _ComWhen being positive polarity, then can be with common electric voltage V _ComBy high reference potential V _Com1Be modulated to low reference potential V _Com2Otherwise, as cross-pressure Δ V _P1With Δ V _P2With respect to common electric voltage V _ComWhen being negative polarity, then can be with common electric voltage V _ComBy low reference potential V _Com2Be modulated to high reference potential V _Com1

Fig. 3 C is the process flow diagram according to a kind of image element driving method of first embodiment of the invention.Fig. 3 D is the common electric voltage V according to the even frame of first embodiment of the invention _Com, cross-pressure Δ V _P1With Δ V _P2The waveform synoptic diagram.Fig. 3 E is the common electric voltage V according to the odd-numbered frame of first embodiment of the invention _Com, cross-pressure Δ V _P1With Δ V _P2The waveform synoptic diagram.With reference to Fig. 3 A, Fig. 3 C, Fig. 3 D and Fig. 3 E, in the present embodiment, first end of transistor 31 is electrically connected to first end of pixel capacitance 21 together, and the gate terminal of transistor 31 is electrically connected to sweep trace SL.First end of transistor 32 is electrically connected to first end of pixel capacitance 22, and the gate terminal of transistor 32 is electrically connected sweep trace SL.In addition, second end of pixel capacitance 21 is electrically connected to shared electrode, and second end of pixel capacitance 22 is electrically connected to shared electrode.The running of each assembly described when following elder generation was directed against second round.

When second round, at first at step S301, the scanning drive signal that high reference potential is provided by the scan drive circuit of LCD is to sweep trace SL, with first end and second end of turn-on transistor 31, and first end of turn-on transistor 32 and second end.Then at step S302, provide data-signal to data line DL by the data drive circuit of LCD, so that pixel capacitance 21,22 is charged.The running of each assembly describes during below again to the period 1.

When the period 1, at step S303, provide the scanning drive signal of hanging down reference potential to sweep trace SL by scan drive circuit, transistor 31,32 is ended, with first end and second end of insulated transistor 31, and first end of insulated transistor 32 and second end.Like this, can avoid the voltage of pixel capacitance 21,22 first ends to interfere with each other.In addition, because the voltage that two ends coupled of pixel capacitance 21,22 is not suspension joint voltage, therefore can improve the image residue problem of prior art.

When the period 1, at step S304, modulation common electric voltage V _Com, the cross-pressure Δ V that pixel capacitance 21 is coupled _P1The cross-pressure Δ V that is coupled with pixel capacitance 22 _P2Differ from one another.In more detail, common electric voltage V can be provided earlier _ComTo shared electrode, and modulate this common electric voltage V _ComThen utilize pixel capacitance 21 to be coupled to first end of transistor 31, and utilize pixel capacitance 22 to be coupled to first end of transistor 32.Thereby, can between first end of first end of transistor 31 and transistor 32, produce cross-pressure.That is, the sub-pixel 51 of pixel 10 has different data-signal-transmittance graphs respectively with 52.

In the present embodiment, pixel 10 for example drives with the positive polarity mode in even frame, and pixel 10 for example drives with the negative polarity mode in odd-numbered frame.Cross-pressure Δ V wherein _P1With Δ V _P2Can calculate according to formula () and formula (two) respectively:

$\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="V\; p"\; filenames="H2008101667981E00032.png,H2008101667981E00061.png"\; state="\{\{state\}\}">V</figure-callout>}}_p=\frac{C_{\mathrm{Lc}1}}{{\mathrm{<figure-callout\; id="1"\; label="C\; St"\; filenames="H2008101667981E00032.png,H2008101667981E00061.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{St}}+{\mathrm{<figure-callout\; id="1"\; label="C\; Lc"\; filenames="H2008101667981E00032.png,H2008101667981E00061.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{Lc}}+{\mathrm{<figure-callout\; id="1"\; label="C\; Gs"\; filenames="H2008101667981E00032.png,H2008101667981E00061.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{Gs}}}\&times;\mathrm{\&Delta;}{V}_{\mathrm{Com}}\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;$ Formula (one)

$\mathrm{\&Delta;}{V}_{p2}=\frac{C_{\mathrm{Lc}2}}{C_{\mathrm{St}2}+C_{\mathrm{Lc}2}+C_{\mathrm{Gs}2}}\&times;\mathrm{\&Delta;}{V}_{\mathrm{Com}}\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;$ Formula (two)

In formula () and (two), C _Lc1With C _Lc2Be respectively the liquid crystal capacitance value of pixel capacitance 21 and 22, C _St1With C _St2Be respectively the storage capacitance value of MM CAP 41 and 42, C _Gs1With C _Gs2Be respectively the parasitic capacitance value of stray capacitance 61 and 62, and Δ V _Com(V _Com1-V _Com2Or V _Com2-V _Com1) be common electric voltage V _ComModulation voltage.Generally speaking, transistor 31 and 32 adopts the assembly of same size, so C _Gs1Usually and C _Gs2Equate, further, C _Gs1With C _Gs2Value very little, therefore can ignore.

Then, in the present embodiment, can pixel 10 be designed to C _Lc1=C _Lc2, and C _St1≠ C _St2Therefore at step S304 modulation common electric voltage V _Com, can make cross-pressure Δ V _P1Be different from cross-pressure Δ V _P2Thereby, can make the sub-pixel 51 of pixel 10 have different data-signal-transmittance graphs respectively with 52, advance to improve the problem of colour cast.In addition, in the present embodiment, sub-pixel 51,52 is couple to identical sweep trace, has improved that each sub-pixel must be couple to different sweep traces in the prior art.Moreover, present embodiment is compared with Fig. 2 A of prior art, and present embodiment has not only promoted reliability, more improved picture inhomogeneous with problem such as image residue.In addition; Present embodiment is compared with prior art Fig. 2 B; The employed sweep trace quantity of present embodiment only is the half the of prior art; Not only can significantly save hardware cost, promote the aperture than, simplified system circuit complexity and need not promote the operating frequency of circuit, therefore have the function of power saving.

Though in the present embodiment pixel 10 is designed to C _Lc1=C _Lc2, and C _St1≠ C _St2, but the present invention is not limited to this.In other embodiments, as long as C _Lc1, C _Lc2, C _St1With C _St2Have Relation, through at step S304 modulation common electric voltage V _Com, can make cross-pressure Δ V _P1Be different from cross-pressure Δ V _P2

Fig. 4 A is the vertical view according to first kind of dot structure of first embodiment of the invention.Fig. 4 B is along the T among Fig. 4 A ₁To T ₁' sectional view.In conjunction with Fig. 3 A, Fig. 4 A and Fig. 4 B, the structure of pixel 10 comprises substrate 410, bias electrode 420, dielectric layer 430, pixel electrode 441,442, liquid crystal layer 450 and shared electrode 460.In the present embodiment, substrate 410 is that example describes with lower-glass 411 with polaroid 412.Bias electrode 420 is disposed on the subregion of substrate 410.Bias electrode 420 for example can be designed with a plurality of openings, and the position of each opening corresponds respectively to sub-pixel 51 and 52.Dielectric layer 430 is disposed on the bias electrode 420.Pixel electrode 441 is disposed on the subregion of dielectric layer 430, and the subregion of the subregion of pixel electrode 441 and bias electrode 420 overlaps mutually and formation MM CAP 41.Pixel electrode 442 is disposed on the subregion of dielectric layer 430, and the subregion of the subregion of pixel electrode 442 and bias electrode 420 overlaps mutually and formation MM CAP 42.

In the present embodiment, bias electrode 420, pixel electrode 441,442 and shared electrode 460 can be formed by opaque material, for example aluminium.Bias electrode 420, pixel electrode 441,442 and shared electrode 460 also can be formed by transparent material, for example tin indium oxide (ITO) but in other embodiments.

Then, liquid crystal layer 450 is disposed on the pixel electrode 441,442.Shared electrode 460 is disposed on the liquid crystal layer 450, and shared electrode 460 forms pixel capacitance 21 and pixel capacitance 22 respectively corresponding to pixel electrode 441 and 442.In addition, also can substrate 470 be disposed on the shared electrode 460.Substrate 470 for example comprises upper glass 471 and polaroid 472.

What deserves to be mentioned is; The areas (width is the annular section of a) that overlap each other owing to pixel electrode 441 and bias electrode 420 are different from pixel electrode 441 and the bias electrode 420 mutual areas (width is the annular section of b) that overlap, so the storage capacitance value C of MM CAP 41 _St1The storage capacitance value C that then is different from MM CAP 42 _St2In addition, in the present embodiment, be identical with 442 area design with pixel electrode 441, so the liquid crystal capacitance value C of pixel capacitance 21 _Lc1Then can with the liquid crystal capacitance value C of pixel capacitance 22 _Lc2Identical.Like this, as modulation common electric voltage V _ComThe time, the cross-pressure that pixel capacitance 21 and 22 is coupled then can be inequality.

In the present embodiment, though be identical with 442 area design, in another embodiment, can be inequality also, so that C with the area design of pixel electrode 441 and 442 with pixel electrode 441 _Lc1≠ C _Lc2For example, Fig. 4 C is the vertical view according to second kind of dot structure of first embodiment of the invention.Fig. 4 D is the T along Fig. 4 C ₁To T ₁' sectional view.Those of ordinary skill in the art can be replaced by the dot structure of Fig. 4 A and Fig. 4 B the dot structure of Fig. 4 C and Fig. 4 D.What deserves to be mentioned is that in Fig. 4 C and Fig. 4 D, c is greater than d, promptly therefore the area of pixel electrode 441 can make C greater than the area of pixel electrode 442 _Lc1≠ C _1c2

In the present embodiment, though bias electrode 420 is formed by the opaque material with a plurality of openings, in other embodiments, bias electrode 420 also can be formed by the transparent material that does not have opening, or is formed by the transparent material with a plurality of openings.

Those of ordinary skill in the art can be designed to the transmission-type pixel with pixel 10 according to demand, to be applied to transmissive type liquid crystal display.In addition, also can pixel 10 be designed to reflective pixel, to be applied to reflective liquid-crystal display.And, also can the sub-pixel 51 of pixel 10 be designed to the transmission-type pixel, and the sub-pixel 52 of pixel 10 is designed to reflective pixel, to be applied to half transmitting-semi-reflecting liquid-crystal display.

Second embodiment

Fig. 5 is a kind of image element circuit figure according to the LCD of second embodiment of the invention.The pixel 11 of present embodiment is similar with the pixel 10 of the foregoing description, and the parts that wherein label is identical with above-mentioned Fig. 1 can be with reference to above-mentioned embodiment.Pixel 11 that it should be noted that present embodiment also comprises MM CAP 43,44.First end of MM CAP 43 and second end are couple to first end and second bias electrode of transistor 31 respectively.First end of MM CAP 44 and second end are couple to first end and second bias electrode of transistor 32 respectively.In the present embodiment, second bias electrode for example can be couple to ground voltage.Therefore as modulation common electric voltage V _ComThe time, the cross-pressure Δ V of pixel capacitance 21 _P1Cross-pressure Δ V with pixel capacitance 22 _P2Can calculate according to formula (three) and formula (four) respectively:

$\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="V\; p"\; filenames="H2008101667981E00032.png,H2008101667981E00061.png"\; state="\{\{state\}\}">V</figure-callout>}}_p=\frac{C_{\mathrm{St}3}+C_{\mathrm{Lc}1}}{{\mathrm{<figure-callout\; id="1"\; label="C\; St"\; filenames="H2008101667981E00032.png,H2008101667981E00061.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{St}}+C_{\mathrm{St}3}+{\mathrm{<figure-callout\; id="1"\; label="C\; Lc"\; filenames="H2008101667981E00032.png,H2008101667981E00061.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{Lc}}+{\mathrm{<figure-callout\; id="1"\; label="C\; Gs"\; filenames="H2008101667981E00032.png,H2008101667981E00061.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{Gs}}}\&times;\mathrm{\&Delta;}{V}_{\mathrm{Com}}\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;$ Formula (three)

$\mathrm{\&Delta;}{V}_{p2}=\frac{{\mathrm{<figure-callout\; id="4"\; label="C\; St"\; filenames="H2008101667981E00042.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{St}}+C_{\mathrm{Lc}2}}{C_{\mathrm{St}2}+{\mathrm{<figure-callout\; id="4"\; label="C\; St"\; filenames="H2008101667981E00042.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{St}}+C_{\mathrm{Lc}2}+C_{\mathrm{Gs}2}}\&times;\mathrm{\&Delta;}{V}_{\mathrm{Com}}\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;$ Formula (four)

In formula (three) and (four), C _Lc1With C _Lc2Be respectively the liquid crystal capacitance value of pixel capacitance 21 and 22, C _St1, C _St2, C _St3With C _St4Be respectively the storage capacitance value of MM CAP 41,42,43 and 44, C _Gs1With C _Gs2Be respectively the parasitic capacitance value of stray capacitance 61 and 62, and Δ V _Com(V _Com1-V _Com2Or V _Com2-V _Com1) be common electric voltage V _ComModulation voltage.

Like this, present embodiment not only can be realized the effect similar with the foregoing description, and present embodiment can also further be stablized pixel voltage through MM CAP 43 and 44, and can make circuit design have more elasticity.Below provide a kind of dot structure of present embodiment of realizing to supply those of ordinary skill in the art's reference.

Fig. 6 A is the vertical view according to a kind of dot structure of second embodiment of the invention.Fig. 6 B is the T along Fig. 6 A ₂To T ₂' sectional view.In conjunction with Fig. 5, Fig. 6 A and Fig. 6 B, the structure similar of the structure of present embodiment pixel 11 and the foregoing description pixel 10, the parts that wherein label is identical with Fig. 4 B with Fig. 4 A can be with reference to above-mentioned embodiment.Structure that it should be noted that present embodiment pixel 11 also comprises public electrode 480.Public electrode 480 is disposed between the subregion and dielectric layer 430 of substrate 410.The subregion of public electrode 480 overlaps mutually with the subregion 491 of pixel electrode 441 and forms MM CAP 43, and the subregion of the subregion of public electrode 480 and pixel electrode 442 overlaps mutually and forms MM CAP 44.

Then, present embodiment is identical with the area of subregion 492 with the area design of subregion 491, so C _St3=C _St4But can be the area that is different from subregion 492 also in another embodiment, so that C with the area design of subregion 491 _St3≠ C _St4Like this, as modulation common electric voltage V _ComThe time, the cross-pressure that pixel capacitance 21 and 22 is coupled then can be inequality.

The 3rd embodiment

Those of ordinary skill in the art can change the framework of pixel according to demand, and for example Fig. 7 is a kind of image element circuit figure according to the LCD of third embodiment of the invention.The pixel 12 of present embodiment is similar with the pixel 10 of above-mentioned Fig. 3 A, and wherein label parts same as the previously described embodiments can be with reference to aforementioned embodiments.It should be noted that the sub-pixel 51,52 of present embodiment lays respectively at the both sides of data line DL, its advantage is to reduce the complicacy of circuit.In addition, pixel 12 also is designed to MM CAP 42 to be in parallel with pixel capacitance 22.Thereby also can realize the effect similar with the foregoing description.

The 4th embodiment

Those of ordinary skill in the art also can be parallel to each pixel capacitance according to the MM CAP that demand is set up varying number.For example Fig. 8 A is a kind of image element circuit figure according to the LCD of fourth embodiment of the invention.The pixel 13 of present embodiment is similar with the pixel 12 of above-mentioned Fig. 7, and wherein label parts same as the previously described embodiments can be with reference to aforementioned embodiments.It should be noted that present embodiment set up the MM CAP 43 that is parallel to pixel capacitance 21.Like this, not only can realize the effect similar, more can make circuit design have more elasticity with the foregoing description.

For example Fig. 8 B is the another kind of image element circuit figure according to the LCD of fourth embodiment of the invention again.The pixel 14 of present embodiment is similar with the pixel 13 of above-mentioned Fig. 8 A, and wherein label parts same as the previously described embodiments can be with reference to aforementioned embodiments.It should be noted that present embodiment set up the MM CAP 44 that is parallel to pixel capacitance 22.Like this, not only can realize the effect similar, more can make circuit design have more elasticity with the foregoing description.

In sum, the present invention utilizes the technology of modulation common electric voltage, and the cross-pressure that pixel capacitance 21 and 22 is coupled is different, therefore can improve color offset phenomenon.

Though described the present invention through above-mentioned several embodiment; But the present invention is not limited to this; Those of ordinary skill under any in the technical field; Do not breaking away from the spirit and scope of the present invention, can make various modifications and modification to it, so protection scope of the present invention is being limited by the accompanying claims.

Claims (20)

1. LCD comprises:

Substrate and corresponding to the relative substrate of said substrate;

Be disposed at bias electrode and public electrode on the said substrate;

First pixel electrode with said bias electrode and said public electrode partly overlap has capacitance C to form respectively _St1First MM CAP with have a capacitance C _St3The 3rd MM CAP;

Second pixel electrode with said bias electrode and said public electrode partly overlap has capacitance C to form respectively _St2Second MM CAP with have a capacitance C _St4The 4th MM CAP; And

Shared electrode, it is disposed on the said relative substrate and overlaps with said first pixel electrode and said second pixel electrode respectively, has capacitance C with formation _Lc1First pixel capacitance with have a capacitance C _Lc2Second pixel capacitance;

Wherein, $\frac{C_{\mathrm{St}3}+C_{\mathrm{Lc}1}}{C_{\mathrm{St}1}+C_{\mathrm{St}3}+C_{\mathrm{Lc}1}}\&NotEqual;\frac{C_{\mathrm{St}4}+C_{\mathrm{Lc}2}}{C_{\mathrm{St}2}+C_{\mathrm{St}4}+C_{\mathrm{Lc}2}}.$

2. LCD according to claim 1, the area that wherein said first pixel electrode and said bias electrode overlap are different from the area of said second pixel electrode and the overlapping of said bias electrode.

3. LCD according to claim 1, the area that wherein said first pixel electrode and said public electrode overlap are different from the area of said second pixel electrode and the overlapping of said public electrode.

4. LCD according to claim 1, the area that wherein said shared electrode and said first pixel electrode overlap are different from the area of said shared electrode and the overlapping of said second pixel electrode.

5. LCD according to claim 1, wherein said bias electrode and said public electrode are integrally formed.

6. LCD according to claim 1, wherein said bias electrode have first opening and second opening.

7. LCD according to claim 6, wherein said first pixel electrode is corresponding to said first opening.

8. LCD according to claim 6, wherein said second pixel electrode is corresponding to said second opening.

9. LCD according to claim 1, wherein said first pixel electrode has the 3rd opening.

10. LCD according to claim 9, wherein said the 3rd opening is positioned at the center of said first pixel electrode.

11. LCD according to claim 1, wherein said second pixel electrode has the 4th opening.

12. LCD according to claim 11, wherein said the 4th opening is positioned at the center of said second pixel electrode.

13. LCD according to claim 1, wherein said first pixel electrode is a transparency electrode, and said second pixel electrode is an opaque electrode.

14. a driving method that is used for LCD as claimed in claim 8 comprises:

In the period 1, common electric voltage is provided to shared electrode;

In the said period 1, modulate said common electric voltage;

In the said period 1, through first end of first pixel capacitance coupling the first transistor;

In the said period 1, through first end of second pixel capacitance coupling transistor seconds; And

In the said period 1, between first end of first end of said the first transistor and said transistor seconds, produce cross-pressure.

15. the driving method of LCD according to claim 14 further comprises:

In the said period 1, first sweep signal is provided to sweep trace;

In the said period 1, make first end and the insulation of second end of said the first transistor; And

In the said period 1, make first end and the insulation of second end of said transistor seconds.

16. the driving method of LCD according to claim 15 further comprises:

In second round, second sweep signal is provided to said sweep trace;

In said second round, said first end and second end of the said the first transistor of conducting; And

In said second round, said first end and second end of the said transistor seconds of conducting.

17. the driving method of LCD according to claim 15 further comprises:

In said second round, data-signal is provided to data line; And

In said second round, to said first pixel capacitance and second pixel capacitance charges.

18. the driving method of LCD according to claim 14 further comprises:

Said sweep trace is electrically connected to the grid of said the first transistor; And

Said sweep trace is electrically connected to the grid of said transistor seconds.

19. the driving method of LCD according to claim 14 further comprises:

Electrically connect first end of said the first transistor and an end of said first pixel capacitance; And

Electrically connect first end of said transistor seconds and an end of said second pixel capacitance.

20. the driving method of LCD according to claim 14 further comprises:

Electrically connect the other end of said shared electrode and said first pixel capacitance; And

Electrically connect the other end of said shared electrode and said second pixel capacitance.

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