CN101308270B - Liquid crystal display device - Google Patents

Abstract

To reduce viewing angle dependence of gamma characteristics in a normally black liquid crystal display. Each pixel 10 has a first sub-pixel 10a and a second sub-pixel 10b which can apply mutually different voltages to their respective liquid crystal layers. Relationships DeltaV12 (gk)>0 volts and DeltaV12 (gk)>=DeltaV12 (gk+1) are satisfied at least in a range 0 <gk<=n-1 if it is assumed that DeltaV12=V1-V2, where DeltaV12 is the difference between root-mean-square voltage V1 applied to the liquid crystal layer of the first sub-pixel 10a and root-mean-square voltage V2 applied to the liquid crystal layer of the second sub-pixel 10b.

Description

Liquid crystal indicator

The application is filed on June 4th, 2003, and application number is " 03147217.6 ", is entitled as the dividing an application of patented claim of " liquid crystal indicator ".

Technical field

The present invention relates to liquid crystal indicator, particularly can improve the dependent structure of field angle and/or the driving method of the γ characteristic of liquid crystal indicator.

Background technology

Liquid crystal indicator is the flat display apparatus with advantages such as high resolving power, thin form, in light weight and consumption electric power are low, in recent years, be accompanied by display performance raising, productive capacity raising and to the raising of the price competitiveness of other display device, market scale enlarges rapidly.

The liquid crystal indicator of the twisted nematic mode that prior art is general (TN mode) can make the major axis with positive anisotropic liquid crystal molecule of dielectric constant approximate parallel-oriented for substrate surface, and, carry out orientation process, the major axis that makes liquid crystal molecule reverses along thickness direction approximate 90 degree between upper and lower base plate of liquid crystal layer.Impressed voltage on liquid crystal layer, liquid crystal molecule parallel electric field ground recovers, and removes twisted-oriented (twist alignment).The liquid crystal indicator of TN mode is followed the variation of liquid crystal molecule according to the optical activity of the change in orientation of voltage by utilization, the control light transmission capacity.

The wide throughput rate of production surplus of the liquid crystal indicator of TN mode is very outstanding.On the one hand, the particularly problem of field angle characteristic of display performance is arranged.Specifically, the words that the display surface of the liquid crystal indicator of TN mode is observed from tilted direction, the contrast of display degree significantly reduces, observe in top view from tilted direction and can obviously observe image, luminance difference between the gray shade scale remarkable unconspicuous problem that becomes is arranged from black to white a plurality of gray shade scales.In addition, the counter-rotating of gray-scale displayed grade characteristic also can occur observing brighter phenomenon (so-called gray shade scale reversal development) from the darker part of top view from tilted direction.

In recent years, as the liquid crystal indicator of the liquid crystal indicator field angle characteristic of improving these TN modes, develop the coplane switching mode (IPS mode) of patent documentation 1 record, the multiple domain perpendicular alignmnet side of patent documentation 2 records), the rotational symmetry aligned (ASM mode) of patent documentation 3 records and the liquid crystal indicator of patent documentation 4 records etc.

All solved above-mentioned particular problem in the liquid crystal indicator of these novel modes (Wide-angle mode) about the field angle characteristic.That is, be not created in the occasion of observing display surface and show problems such as contrast significantly reduces, the counter-rotating of display gray scale grade from tilted direction.

Patent documentation 1: special public clear 63-21907 communique

Patent documentation 2: the spy opens flat 11-242225 communique

Patent documentation 3: the spy opens flat 10-186330 communique

Patent documentation 4: the spy opens the 2002-55343 communique

Under the situation that the improvement of the display quality of liquid crystal indicator gets along with, current problem as the field angle characteristic, the different this point of γ characteristic when the γ characteristic during top view is observed with tilted direction, that is the dependent problem of the field angle of γ characteristic displays again.Here, so-called γ characteristic is the gray shade scale dependence of expression brightness, the γ characteristic is different with tilted direction at frontal, because the gray shade scale show state is direction and difference according to the observation, so occasion at images such as expression photos, perhaps the occasion of televising etc. in demonstration can go wrong especially.

The dependent problem of the field angle of γ characteristic is more remarkable than IPS mode under MVA mode and ASM mode.On the one hand, the IPS mode is compared with MVA mode or ASM mode, the high panel of contrast when being difficult to high throughput rate production top view.From this point, special expectation improve the MVA mode and or the liquid crystal indicator of ASM mode in the field angle dependence of γ characteristic.

Summary of the invention

The present invention uses for reference such problem exploitation, and its fundamental purpose provides the good liquid crystal indicator of field angle dependence of γ characteristic.

Liquid crystal indicator according to a first aspect of the invention is a plurality of pixels that have a plurality of liquid crystal layers and a plurality of electrodes of impressed voltage on above-mentioned liquid crystal layer are arranged, carry out the liquid crystal indicator that normal black formula shows, each that it is characterized in that above-mentioned a plurality of pixels has the plain and second secondary image element of first secondary image that can add different mutually voltage on above-mentioned each liquid crystal layer, each of above-mentioned a plurality of pixels is being carried out certain gray shade scale gk (0≤gk≤gn, gk and gn are the integers more than 0, the high gray shade scale of side expression brightness that gk is big, n represents the highest gray shade scale) demonstration the time, making the effective voltage on each liquid crystal layer that is added to above-mentioned first secondary image element and the second secondary image element is V1 (gk) and V2 (gk), the words of Δ V12 (gk)=V1 (gk)-V2 (gk), then at least in the scope of 0＜gk≤n-1, Δ V12 (gk)＞0 (volt), and satisfy the relation of Δ V12 (gk) 〉=Δ V12 (gk+1), realize above-mentioned purpose with this.

Each of above-mentioned a plurality of pixels has the 3rd secondary image element that can add the voltage different with plain and above-mentioned second secondary image element of above-mentioned first secondary image on liquid crystal layer in addition, each of above-mentioned a plurality of pixels makes the effective voltage on the above-mentioned liquid crystal layer that is added to above-mentioned the 3rd secondary image element when carrying out the demonstration of certain gray shade scale gk be V3 (gk), Δ V13 (gk)=V1 (gk)-V3 (gk), also can satisfy the relation of 0 (volt)＜Δ V13 (gk)＜Δ V12 (gk).

In addition, at least in the scope of 0＜gk≤n-1, preferably satisfy the relation of Δ V12 (gk)＞Δ V12 (gk+1) at the effective voltage that adds on the liquid crystal layer of secondary image element.

Each pixel in the scope of 0＜gk≤n-1, preferably satisfies the relation of Δ V12 (gk)＞Δ V12 (gk+1) and Δ V13 (gk)＞Δ V13 (gk+1) at least in the occasion that the 3rd secondary image element is arranged.

In certain suitable embodiment, each of the plain and above-mentioned second secondary image element of above-mentioned first secondary image has by opposite electrode and the liquid crystal capacitance that forms by above-mentioned liquid crystal layer and the opposed sub-pixel electrode of above-mentioned opposite electrode, with by the auxiliary capacitance electrode that is electrically connected with above-mentioned sub-pixel electrode, insulation course, auxiliary capacitor by above-mentioned insulation course and the opposed auxiliary capacitor opposite electrode formation of above-mentioned auxiliary capacitance electrode, above-mentioned opposite electrode is to the plain common unitary electrode of plain and above-mentioned second secondary image of above-mentioned first secondary image, each electric independence of above-mentioned auxiliary capacitor opposite electrode and above-mentioned first secondary image element and the above-mentioned second secondary image element.Opposite electrode typically is provided with (also claiming " common electrode " sometimes) on counter substrate, but in the IPS mode, forms on the substrate identical with sub-pixel electrode.In addition, " by liquid crystal layer and the opposed opposite electrode of sub-pixel electrode " not necessarily need be opposed in the thickness direction and the sub-pixel electrode of liquid crystal layer, in IPS mode liquid crystal indicator, in the aspect of liquid crystal layer by liquid crystal layer and opposed such configuration of sub-pixel electrode.

In certain suitable embodiment, 2 on-off elements with each setting of corresponding above-mentioned first secondary image element and the above-mentioned second secondary image element, above-mentioned two on-off elements carry out on by the scanning voltage signal of supplying with the common scanning line, at above-mentioned 2 on-off elements during in on-state, on the above-mentioned sub-pixel electrode that each had of and the above-mentioned second secondary image element plain and the above-mentioned auxiliary capacitance electrode at above-mentioned first secondary image from common signal wire supply shows signal voltage, after above-mentioned 2 on-off elements become off-state, the change in voltage of the above-mentioned auxiliary capacitor opposite electrode of each of the plain and above-mentioned second secondary image element of above-mentioned first secondary image is different by the variable quantity of the size regulation of the direction of its variation and variation in above-mentioned first secondary image element and the above-mentioned second secondary image element.Here, the variable quantity of the voltage of above-mentioned auxiliary capacitor opposite electrode not only comprises size (absolute value) but also comprises the direction (symbol) of variation.For example, it is identical that the variable quantity of the voltage of the above-mentioned auxiliary capacitor opposite electrode of each of the plain and above-mentioned second secondary image element of above-mentioned first secondary image also can absolute value, opposite in sign.That is, after on-off element becomes off-state, increase at the voltage of a side auxiliary capacitor opposite electrode, the occasion that the voltage of the opposing party's auxiliary capacitor opposite electrode reduces, the absolute value of its variable quantity also can be identical.

Above-mentioned liquid crystal layer is the vertical alignment-type liquid crystal layer preferably, comprises the nematic liquid crystal material with negative electricity medium anisotropy.

The azimuth direction of liquid crystal molecules tilt differed 4 territories of 90 ° mutually when the above-mentioned liquid crystal layer that comprises in each of above-mentioned first secondary image element and the above-mentioned second secondary image element preferably was included in impressed voltage.

Dispose by above-mentioned common scanning line in the middle of the plain and above-mentioned second secondary image element of above-mentioned first secondary image, each of above-mentioned first secondary image element and the above-mentioned second secondary image element is at the outstanding a plurality of ribs of the oriented above-mentioned liquid crystal layer side of above-mentioned opposite electrode side, above-mentioned a plurality of rib is included in the upwardly extending first rib of first party, with with the upwardly extending second rib of the second party of above-mentioned first direction nearly orthogonal, opposing parallel is in the center line balanced configuration of above-mentioned common scanning line in each of above-mentioned first rib and above-mentioned the second rib plain and above-mentioned second secondary image element at above-mentioned first secondary image, and, the interior configuration of the above-mentioned first rib of the secondary image element of the side in the plain and above-mentioned second secondary image element of above-mentioned first secondary image and the configuration of above-mentioned second rib and the opposing party's secondary image element best for the center line symmetry of above-mentioned common scanning line quadrature.

The interval that is parallel to the center line of the above-mentioned common scanning line in each of the plain and above-mentioned second secondary image element of above-mentioned first secondary image preferably equal above-mentioned sweep trace arrangement pitches about 1/2nd.

The area of the above-mentioned first secondary image element is preferably identical or littler than it with the area of the above-mentioned second secondary image element.Have the occasion of the secondary image element more than 3 in each of a plurality of pixels, the area that adds the secondary image element of the high effective voltage preferably area of secondary image element unlike other is big.

Liquid crystal indicator according to a further aspect in the invention, it is characterized in that, the direction of the above-mentioned electric field that adds on the above-mentioned liquid crystal layer of above-mentioned a plurality of pixels is in each vertical-scan period counter-rotating, be under a certain middle gray grade show state, above-mentioned direction of an electric field in the pixel of any row, on the line direction with the periodic reversal of regulation, and, in the pixel that is listed as arbitrarily, every pixel inversion on column direction.

In certain embodiments, above-mentioned direction of an electric field in the pixel of any row, every pixel inversion on line direction.

In certain embodiments, above-mentioned direction of an electric field in the pixel of any row, per two pixel inversion on line direction.

The liquid crystal indicator of certain embodiment is to carry out the liquid crystal indicator that shows with normal black formula, above-mentioned at least two secondary image elements comprise two secondary image element (SPa (p, q) and SPb (p, q)), each of above-mentioned a plurality of pixels is being carried out certain gray shade scale gk (0≤gk≤gn, gk and gn are the integers more than 0, the high gray shade scale of side expression brightness that gk is big, n represents the highest gray shade scale) demonstration the time, making the effective voltage on the above-mentioned liquid crystal layer that is added to the side in above-mentioned two secondary image elements is V1 (gk), the effective voltage that is added on the opposing party's the above-mentioned liquid crystal layer is V2 (gk), the words of Δ V12 (gk)=V1 (gk)-V2 (gk), then at least in the scope of 0＜gk≤n-1, Δ V12 (gk)＞0 (volt), and satisfy the relation of Δ V12 (gk) 〉=Δ V12 (gk+1).

In certain embodiments, in the scope of 0＜gk≤n-1, satisfy the relation of Δ V12 (gk)＞Δ V12 (gk+1) at least.

In certain embodiments, SPa (p, q) and SPb (p, q) each has by opposite electrode and the liquid crystal capacitance that forms by above-mentioned liquid crystal layer and the opposed sub-pixel electrode of above-mentioned opposite electrode, with by the auxiliary capacitance electrode that is electrically connected with above-mentioned sub-pixel electrode, insulation course, auxiliary capacitor by above-mentioned insulation course and the opposed auxiliary capacitor opposite electrode formation of above-mentioned auxiliary capacitance electrode, above-mentioned opposite electrode is to SPa (p, q) and SPb (p, q) common unitary electrode, above-mentioned auxiliary capacitor opposite electrode and SPa (p, q) and SPb (p, the electric independence of q) each.

In one embodiment, has corresponding SPa (p, q) and SPb (p, 2 on-off elements of each setting q), above-mentioned two on-off elements carry out on by the scanning voltage signal of supplying with the common scanning line, at above-mentioned 2 on-off elements during in on-state, at SPa (p, q) and SPb (p, q) supply with shows signal voltage from common signal wire on above-mentioned sub-pixel electrode that each had and the above-mentioned auxiliary capacitance electrode, after above-mentioned 2 on-off elements become off-state, and SPa (p, q) and SPb (p, the change in voltage of the above-mentioned auxiliary capacitor opposite electrode of q) each, by the variable quantity of the size regulation of the direction of its variation and variation SPa (p, q) and SPb (p, q) difference.That is to say, SPa (the p of above-mentioned two on-off elements when on-state, q) and SPb (p, the current potential of the above-mentioned auxiliary capacitor opposite electrode of q) each for example is VSpa (on) and VSpb (on), after above-mentioned two on-off elements are becoming off-state, be changed to VSpa (off) and VSpb (off) respectively from VSpa (on) and VSpb (on), and, with as each different impressed voltages on above-mentioned auxiliary capacitor opposite electrode like that of variable quantity VSpa (off)-VSpa (on) this moment with VSpb (off)-VSpb (on)

In certain embodiments, SPa (p, q) and SPb (p, the variable quantity equal and opposite in direction of the voltage of above-mentioned auxiliary capacitor opposite electrode q), the direction of variation are opposite.

In certain embodiments, SPa (p, q) and SPb (p, the voltage of the above-mentioned auxiliary capacitor opposite electrode of q) each is that oscillating voltage, phase place are opposite each other.Above-mentioned oscillating voltage can be a square wave, also can be sine wave or triangular wave etc.

In certain embodiments, and SPa (p, q) and SPb (p, the cycle of the above-mentioned oscillating voltage of the above-mentioned auxiliary capacitor opposite electrode of q) each and a horizontal scanning period approximately equal.

In certain embodiments, SPa (p, q) and SPb (p, horizontal scanning period of the period ratio of the above-mentioned oscillating voltage of the above-mentioned auxiliary capacitor opposite electrode of q) each is short.

In certain embodiments, SPa (p, q) and SPb (p, the time average of the horizontal scanning period of the above-mentioned oscillating voltage of the above-mentioned auxiliary capacitor opposite electrode of q) each is in any horizontal scanning period approximately equal.

In certain embodiments, the above-mentioned vibration period is 1/2nd of a horizontal scanning period.

In certain embodiments, above-mentioned vibration is that load (duty) is than the square wave that is 1: 1.

In certain embodiments, SPa (p, area q) and SPb (p, area q) are different mutually, and SPa (p, q) and SPb (p, q) side's that the effective voltage that adds on the above-mentioned liquid crystal layer in is big area is littler than the opposing party's area.

In certain embodiments, (p, (p, area essence q) equates SPa for area q) and SPb.

Description of drawings

The example of the dot structure in the liquid crystal indicator 100 of Fig. 1 representation of concept embodiment according to a first aspect of the invention.

Fig. 2 (a) ~ (c) is the concept map of structure of the liquid crystal indicator of expression embodiments of the invention.

The liquid crystal indicator 100 of Fig. 3 (a) ~ (c) representation of concept prior art ' structure.

Fig. 4 is the concept map for the display characteristic of the liquid crystal indicator of explanation MVA mode, (a) be the curve map of the impressed voltage dependence of expression transmissivity, (b) be the standardized curve map of transmissivity during with white show the curve map of (a) respectively, (c) be the curve map of expression γ characteristic.

Fig. 5 (a) ~ (d) is illustrated respectively in the voltage conditions A ~ D that adds on the liquid crystal layer of the secondary image element after the pixel segmentation.

Fig. 6 is the curve map of the γ characteristic of the expression occasion of using voltage conditions A ~ D shown in Figure 5, (a) the γ characteristic of the right 60 degree field angle of expression, (b) the γ characteristic of the upper right 60 degree field angle of expression.

The curve map of transmissivity (front) when Fig. 7 is white demonstration of the expression occasion of using voltage conditions A ~ D shown in Figure 5.

Fig. 8 compares the curve map of the influence of the γ characteristic of the occasion of working voltage condition C in an embodiment according to the present invention for the area of explanation secondary image element, (a) the γ characteristic of the right 60 degree field angle of expression, (b) the γ characteristic of the upper right 60 degree field angle of expression.

Fig. 9 is the figure of transmissivity (front) and the relation of the area ratio of secondary image element when representing that the occasion of working voltage condition C shows in vain in an embodiment of the present invention.

Figure 10 be for the number of explanation secondary image element to the curve map of the influence of the γ characteristic of the occasion of working voltage condition B in an embodiment of the present invention, (a) the right 60 degree field angle γ characteristics of expression, (b) the upper right 60 degree field angle γ characteristics of expression.

Figure 11 is the figure of transmissivity (front) and the relation of the number of secondary image element when representing that the occasion of working voltage condition B shows in vain in an embodiment of the present invention.

Figure 12 is the figure of an example of dot structure of the liquid crystal indicator 200 of representation of concept another one embodiment of the present invention.

Figure 13 is the figure of electrical equivalent circuit of the dot structure of the corresponding liquid crystal indicator 200 of expression.

Figure 14 (a) ~ (f) is the figure that is illustrated in the various voltage waveforms that use in the driving of liquid crystal indicator 200.

Figure 15 is the figure that the impressed voltage of liquid crystal layer concerns between the secondary image element in the expression liquid crystal indicator 200.

Figure 16 is the figure of the γ characteristic of expression liquid crystal indicator 200, (a) the γ characteristic of the right 60 degree field angle of expression, (b) the γ characteristic of the upper right 60 degree field angle of expression.

Figure 17 is the figure that the pixel of the liquid crystal indicator of representation of concept a second aspect of the present invention is arranged.

Figure 18 (a) ~ (j) is the figure that is expressed as the waveform of the various voltages (signal) that drive the liquid crystal indicator with structure shown in Figure 17.

Figure 19 is the figure that the pixel of the liquid crystal indicator of representation of concept an alternative embodiment of the invention is arranged.

Figure 20 (a) ~ (j) is the figure that is expressed as the waveform of the various voltages (signal) that drive the liquid crystal indicator with structure shown in Figure 19.

Figure 21 (a) is the figure that the pixel of representation of concept liquid crystal indicator is according to another embodiment of the invention arranged, and (b) is the figure of the configuration of its auxiliary capacitor distribution of representation of concept and auxiliary capacitance electrode.

Embodiment

Structure and operation below with reference to the liquid crystal indicator of accompanying drawing embodiment to the first aspect of the present invention describe.

At first and (c) with reference to figure 1 and Fig. 2 (a) and (b).The electrode configuration of 1 pixel of the liquid crystal indicator 100 of Fig. 1 representation of concept embodiments of the invention.The one-piece construction of Fig. 2 (a) representation of concept liquid crystal indicator 100, the electrode structure of 1 pixel of Fig. 2 (b) representation of concept, Fig. 2 (c) expression is along the sectional view of the 2C-2C ' line of Fig. 2 (b).In addition for reference to for the purpose of, in Fig. 3 (a), 3 (b) and 3 (c), distinguish the representation of concept prior art liquid crystal indicator 100 ' 1 pixel electrode configuration, electrode structure and along the profile construction of 3C-3C ' line.

The liquid crystal indicator 100 of present embodiment is equipped with a plurality of a plurality of pixels that have liquid crystal layer and give a plurality of electrodes of liquid crystal layer impressed voltage, is to carry out the liquid crystal indicator that common black formula shows.Here, with the expression for example of TFT type liquid crystal indicator, but also can use other on-off element (for example MIM element).

Liquid crystal indicator 100 has a plurality of pixels 10 of arranging with matrix form.Each of a plurality of pixels 10 has liquid crystal layer 13 and is pixel electrode 18 and opposite electrode 17 to liquid crystal layer 13 impressed voltages.Opposite electrode 17 is electrodes common to whole pixel 10.

The liquid crystal indicator 100 of present embodiment, as shown in Figure 1, each of a plurality of pixels 10 has plain 10a of first secondary image that can add different mutually voltage and the plain 10b of second secondary image.

Each of a plurality of pixels 10 is being carried out a certain gray shade scale gk (0≤gk≤gn, gk and gn are zero above integers, the high gray shade scale of side expression brightness that gk is big, n represents the highest gray shade scale) demonstration the time drive like this, make the effective voltage that on each the liquid crystal layer of the plain 10a of first secondary image and the second amplitude pixel 10b, adds be respectively V1 (gk) and V2 (gk), the difference of the effective voltage that adds on each the liquid crystal layer of the plain 10a of first secondary image and the second amplitude pixel 10b is the words of Δ V12 (gk)=V1 (gk)-V2 (gk), at least Δ V12 (gk)＞0 (volt) in the scope of 0＜gk≤n-1, and satisfy the relation of Δ V12 (gk) 〉=Δ V12 (gk+1).

The number of the secondary image element that each pixel 10 has (being sometimes referred to as the number of cutting apart of pixel) is not limited to 2, also can have the plain (not shown) of the 3rd secondary image that can add with plain 10a of first secondary image and the different voltages of the plain 10b of second secondary image in addition.At this moment, give effective voltage that the liquid crystal layer of the 3rd secondary image element adds as V3 (gk), give the plain and effective voltage that the 3rd secondary image element liquid crystal layer separately adds of first secondary image difference as Δ V13 (gk)=V1 (gk)-V3 (gk), then satisfy the relation of 0 (volt)＜Δ V13 (gk)＜Δ V12 (gk).Much less, the number of the secondary image element that has of each pixel 10 also can be more than 4.

In addition, in the scope of 0＜gk≤n-1, preferably satisfy the relation of Δ V12 (gk)＞Δ V12 (gk+1) at least at the effective voltage that adds on the liquid crystal layer of secondary image element.That is to say, the gray shade scale that brightness is high more, the difference of the effective voltage that adds on plain 10a of first secondary image and the plain 10b of second secondary image is more little, perhaps preferably equates.In other words, the gray shade scale (near the black degree that shows) that brightness is low more, the difference that is preferably in the effective voltage that adds on plain 10a of first secondary image and the plain 10b of second secondary image is big, perhaps equates.Each pixel preferably satisfies the relation of Δ V12 (gk) 〉=Δ V12 (gk+1) and Δ V13 (gk)＞Δ V13 (gk+1) at least in the occasion with the 3rd secondary image element in the scope of 0＜gk≤n-1.

The area of the plain 10a of first secondary image is preferably identical or littler with the area of the plain 10b of second secondary image.Each has the occasion of the secondary image element more than 3 in a plurality of pixels, adds the area that the area of the secondary image element (being the first secondary image element) of high effective voltage preferably is not more than the secondary image element (being the second secondary image element) that adds minimum effective voltage here here.That is to say, each pixel 10 have a plurality of secondary images plain SP1, SP2 ... SPn, the effective voltage of adding for each liquid crystal layer is V1 (gk), V2 (gk) ... words, preferably satisfy V1 (gk)＞V2 (gk) ... the relation of＞Vn (gk), the area of each secondary image element be SSP1, SSP2 ... SSPn preferably satisfies SSP1≤SSP2 ... the relation of≤SSPn.

In addition, if V1 (gk)＞V2 (gk) ... the relation of＞Vn (gk) is at least in all gray shade scale (that is scope of 0＜gk≤n-1) establishments down except that minimum gray shade scale and the highest gray shade scale, then obtain effect of the present invention, but also can be used as the formation of setting up down in whole gray shade scales (that is scope of 0≤gk≤n-1).

Like this, cutting apart each pixel is a plurality of secondary image elements, when adding different voltage on the liquid crystal layer of each secondary image element, observes under the state that different γ characteristics is mixed, and can improve the field angle dependence of γ characteristic.And then, because the effective voltage difference between the secondary image element is big when being set in low gray shade scale, so it is big to improve the effect of the γ characteristic of black side (side that brightness is low) under normal black formula, the effect height that display quality improves.

The structure that adds the effective voltage that satisfies above-mentioned relation on the liquid crystal layer of plain 10a of secondary image and 10b can be various structures.

For example, as shown in Figure 1 the such structure of liquid crystal indicator 100 can be arranged.That is to say, for the liquid crystal indicator 100 of prior art shown in Figure 3 ' in, 1 pixel 10 has the unique pixel electrode 18 that connects signal wire 14 by TFT16, in liquid crystal indicator 100, have by each corresponding TFT16a to be connected different mutually signal wire 14a and sub-pixel electrode 18a and the 18b of 14b with 16b.

Because plain 10a of secondary image and 10b constitute a pixel 10, so the door of TFT16a and 16b is connected common scanning line (bus) 12, carries out on by identical sweep signal.Satisfy the such signal voltage of above-mentioned relation (grayscale voltage) at signal wire (source bus) 14a and last supply of 14b.In addition, the door of TFT16a and TFT16b is preferably public.

Perhaps, the back will describe in detail, each of first secondary image element and the second secondary image element, in the structure that has by the auxiliary capacitance electrode that is electrically connected with sub-pixel electrode, insulation course, the auxiliary capacitor that forms by insulation course and the opposed auxiliary capacitor opposite electrode of auxiliary capacitance electrode, make the plain and plain electric independence of second secondary image of auxiliary capacitor opposite electrode and each first secondary image, make the voltage of supplying with the auxiliary capacitor opposite electrode (be called the opposed voltage of auxiliary capacitor.) change, thus electric capacity is cut apart, preferably make the effective voltage on the liquid crystal layer of the liquid crystal layer that is added to the first secondary image element and the second secondary image element different.The size of the capacitance by regulating auxiliary capacitor and supply with the size of the voltage of auxiliary capacitor opposite electrode can be controlled the size of the effective voltage on the liquid crystal layer that is added to each secondary image element.

When adopting such structure,, can be connected to TFT16a and TFT16b on the common signal wire, supply with same signal voltage because do not need each to add different signal voltages to sub-pixel electrode 18a and 18b.Therefore, ' identical, the structure of signal-line driving circuit also can adopt the identical structure of using with liquid crystal indicator 100 ' in prior art for the radical of signal wire and the liquid crystal indicator of prior art shown in Figure 3 100.Much less,, also can adopt the structure of shared door like this because TFT16a is connected on the identical sweep trace with TFT16b, identical with top example.

Liquid crystal indicator of the present invention goes for utilizing the liquid crystal indicator of the vertical alignment-type liquid crystal layer that comprises the nematic liquid crystal material with negative electricity medium anisotropy.About 90 ° 4 territories (domain) (MVA mode) of the azimuth direction phase mutual deviation of liquid crystal molecules tilt when especially, the liquid crystal layer that comprises in each secondary image element can be included in impressed voltage.Perhaps, the liquid crystal layer that comprises in each secondary image element also can be a liquid crystal layer of getting the rotational symmetry orientation during at least at impressed voltage.

The liquid crystal indicator 100 of the MVA mode in about 90 ° 4 territories (domain) (MVA mode) of the azimuth direction phase mutual deviation of liquid crystal molecules tilt illustrates in greater detail embodiments of the invention when being included in impressed voltage about the liquid crystal layer of each secondary image element below.

In addition, the liquid crystal indicator 100 of MVA mode as representation of concept among Fig. 2 (a), phase difference compensating element (being typically the phase difference compensation plate) 20a and the 20b, the Polarizer 30a that clips these configurations and 30b and the back of the body light 40. that have liquid crystal panel 10A and be provided with in the both sides of liquid crystal panel 10A.The mutually orthogonal configuration of the penetrating shaft of Polarizer 30a and 30b (being also referred to as polarizing axis) (crossed nicols configuration), the state of impressed voltage (vertical orientated state) is not carried out black the demonstration down on the liquid crystal layer (not shown) of liquid crystal panel 10A.For the field angle characteristic that makes liquid crystal indicator well is provided with phase difference compensating element 20a and 20b, can use technique known the most suitably to design.Specifically, (gk=0) carry out optimumization under the black show state, when the tilted direction of all azimuth directions is observed and the difference of the brightness (shiny black degree) during top view minimum.By making phase difference compensating element 20a and optimumization of 20b, more remarkable effect of the present invention like this.

Also have, certainly, for on sub-pixel electrode 18a and 18b, adding the signal voltage of regulation, on substrate 11a, form sweep trace 12, signal wire 14a, 14b and TFT16a, TFT16b (with reference to figure 1) as required, and then form the circuit that drives these etc. with each predetermined timing.In addition, on another substrate 11b, color filter is set as required.

The limit with reference to figure 2 (b) and (c), the structure of 1 pixel of the liquid crystal indicator 100 of limit explanation MVA mode.About the basic structure and the operation of the liquid crystal indicator of MVA mode, for example open in flat 11 1 No. 222425 communiques open the spy.

As illustrated with reference to figure 1, the pixel 10 of liquid crystal indicator 100 has plain 10a of two secondary images and 10b, and the plain 10a of secondary image has sub-pixel electrode 18a, and the plain 10b of secondary image has sub-pixel electrode 18b.As Fig. 2 (c) representation of concept, the sub-pixel electrode 18a that forms on glass substrate 11a (with the 18b (not shown)) has slit 18s, uses by liquid crystal layer 13 opposed such opposite electrodes that are provided with 17 and produces oblique electric field.In addition, on the surface of the glass substrate 11b that opposite electrode 17 is set, be arranged on the outstanding rib 19 of liquid crystal layer side.Liquid crystal layer 13 is made of the nematic liquid crystal material with negative electricity medium anisotropy, uses the vertical alignment layer (not shown) form as will covering opposite electrode 17, rib 19 and sub-pixel electrode 18a and 18b to get the near normal state of orientation when impressed voltage not.By the surface (side of inclination) and the above-mentioned oblique electric field of rib 19, can on the direction of regulation, stably fall vertical orientated liquid crystal molecule.

Shown in Fig. 2 (c), rib 19 tilts with the mountain type to the center of rib, and liquid crystal molecule is to its dip plane near normal orientation.Therefore, because rib 19 produces the distribution at the angle of inclination (angle that the major axis of substrate surface and liquid crystal molecule forms) of liquid crystal molecule.In addition, slit 18s changes the direction of the electric field that adds to liquid crystal layer regularly.Its result, because the effect of rib 19, slit 18s, the direction of orientation of the liquid crystal molecule during extra electric field can obtain the direction of the arrow shown in the figure, that is to say to have the good field angle characteristic of the characteristic of symmetry up and down of orientation usefulness on upper right, upper left, lower-left, 4 directions in bottom right.And then the rectangle display surface of liquid crystal panel 10A is typically to make vertically and disposes on left and right directions, and the light transmission shaft of Polarizer 30a is parallel to vertical setting.On the one hand, pixel 10 typically shown in Fig. 2 (b), make pixel 10 vertically and the direction of vertical quadrature of liquid crystal panel 10A dispose.

Shown in Fig. 2 (b), the plain 10a of first secondary image is identical with the area of the plain 10b of second secondary image, in each secondary image element, be included in first rib that first direction extends and with the upwardly extending second rib of second party of first direction nearly orthogonal direction, first rib and second rib in each secondary image element for the center line balanced configuration that is parallel to sweep trace 12, and, the configuration of the rib in secondary image element and the configuration of the rib in another secondary image element can for the center line balanced configuration of sweep trace quadrature.By such configuration, liquid crystal molecule in each secondary image element is orientated on upper right, upper left, lower-left, 4 directions in bottom right, and, close and the pixel integral body that comprises first secondary image element and the second secondary image element, because the area of each liquid crystal region is identical in fact, so can obtain having the good field angle characteristic of the characteristic of symmetry up and down.This effect is hour very remarkable at the area of pixel.Further, can adopt the interval of the center line parallel to equal about 1/2nd structure of the arrangement pitch of sweep trace with the sweep trace in each secondary image element.

The following describes the operation and the display characteristic of the liquid crystal indicator 100 of embodiments of the invention.

At first, have and the liquid crystal indicator 100 shown in Figure 3 ' display characteristic of the liquid crystal indicator of the MVA mode of the prior art of same electrode structure with reference to figure 4 explanations.In addition, it is identical generally to add the liquid crystal indicator of the display characteristic of occasion of same effective voltage and prior art on the liquid crystal layer of the plain 10a of the secondary image of the liquid crystal indicator 100 of embodiments of the invention and 10b (that is sub-pixel electrode 18a and 18b).

Fig. 4 (a) is the dependency characteristic of impressed voltage of the transmissivity at frontal (N1) and right 60 degree visual angles (L1), upper right 60 degree visual angles (LU1).Fig. 4 (b) is that the transmissivity of expression when pressing (the highest grayscale voltage) with the white appliances that add all directions is the figure of the standardization transmissivity after the transmissivity of all directions of 100% standardization Fig. 4 (a), and the dependency characteristic of impressed voltage of the standardization transmissivity at visual angles (LU2) is spent at expression frontal (N2) and right 60 degree visual angles (L2), upper right 60.In addition, visual angle 60 degree mean that from the angle of display surface normal be 60 degree.

From Fig. 4 (b) as can be seen, the display characteristic of frontal is different with the characteristic at upper right 60 degree visual angles with right 60 degree visual angles.The γ characteristic difference that this true expression shows according to each direction of observation.

Fig. 4 (c) is for further clearly showing the different figure of γ characteristic, the value of getting transverse axis is that the value of transverse axis value=(positive visual angle standardization transmissivity ÷ 100) ^ (1/2.2), the longitudinal axis is spent visual angle scale grade characteristics=(upper right 60 degree standardization transmissivity ÷ 100) ^ (1/2.2) for front scale grade characteristic=(positive visual angle standardization transmissivity ÷ 100) ^ (1/2.2) of difference corresponding N3, L3, LU3, right 60 degree visual angle scale grade characteristics=(right 60 degree standardization transmissivity ÷ 100) ^ (1/2.2), upper right 60, and the skew of γ characteristic is obviously changed." ^ " represents power, the corresponding γ value of this index, and the γ value of front scale grade characteristic is set at 2.2 in typical liquid crystal indicator.

In Fig. 4 (c), front scale grade characteristic (N3) is longitudinal axis value=transverse axis value, is in line.On the one hand, the scale grade characteristic (LU3) at right 60 degree visual angle scale grade characteristics (L3) and upper right 60 degree visual angles becomes curve.From represent this curve (L3, the side-play amount of the γ characteristic in each visual angle of side-play amount quantificational expression of the straight line of positive characteristic LU3) (N3) that is when top view with each visual angle (right 60 degree visual angles and upper right 60 degree visual angles) under the side-play amount (different) of gray shade scale show state of observation.

The objective of the invention is to be reduced in this side-play amount in the normal black formula liquid crystal indicator.It is desirable to wish represent that (L3 LU3) becomes and the consistent straight line of scale grade characteristic (N3) in front for each curve of the scale grade characteristic at right 60 degree visual angles and upper right 60 degree visual angles.Below, and Fig. 4 (c) is same, the figure of the side-play amount by expression γ characteristic estimates the degree of improving effect of γ characteristic.

With reference to figure 4 (b), illustrate according to the present invention that is by the plain and second secondary image element of first secondary image being set in each pixel, adding the principle that different effective voltage V1 and V2 can improve the skew of γ characteristic to the liquid crystal layer of each secondary image element.But, first secondary image area plain and the second secondary image element is equated.

The liquid crystal indicator 100 of prior art ' in when representing positive transmissivity with a NA, the transmissivities at right 60 degree visual angles are with representing and put that the some LA that the transmissivity at visual angles is spent on the right side 60 of the same voltage of NA represents.To this,,, can select the plain and second secondary image element positive transmissivity separately of first secondary image at a NB1 and some NB2 for obtaining the positive transmissivity of a NA in occasion of the present invention.Here, the positive transmissivity approximate zero of some NB2, first secondary image area plain and the second secondary image element equates that the positive transmissivity of therefore putting NB1 is about twice of the positive transmissivity of a NA simultaneously.In addition, the difference of the effective voltage on some NB1 and the some NB2 is Δ V12.In addition, in occasion of the present invention, the transmissivity at right 60 degree visual angles becomes expression and puts NB1 and the point of the transmissivity at 60 degree visual angles, the right side of the same voltage of some NB2, the point of the mean value of the transmissivity of an expression LB1 and some LB2, some P.

Expression according to the some P of the transmissivity at the degree visual angles, the right side 60 of liquid crystal indicator of the present invention than the expression prior art liquid crystal indicator 100 ' the some NA of the suitable positive transmissivity of the more approaching expression of some LA of transmissivity at 60 degree visual angles, the right side, reduced the side-play amount of γ characteristic.

From above-mentioned explanation, the right side 60 that is appreciated that the second secondary image element of the present invention is spent this fact of transmissivity (reference point LB2) approximate zero at visual angles and effect of the present invention is increased, also be and improve effect of the present invention, can under black show state, not increase the transmissivity of observing occasion from tilted direction.From this viewpoint, can suitably set phase difference compensating element 20a, the 20b of Fig. 2 (a) expression, making under black show state does not increase the transmissivity of observing occasion from tilted direction.

Liquid crystal indicator 100 according to an embodiment of the invention, and adding mutually by the plain 10a of two secondary images having for each pixel 10 with 10b liquid crystal layer separately, different voltage improves the γ characteristic.At this moment, set poor Δ V12 (gk)=V1 (the gk)-V2 (gk) of the effective voltage that adds on plain 10a of secondary image and the plain 10b of the secondary image liquid crystal layer separately, make and satisfy Δ V12 (gk)＞0 (volt), and the relation of Δ 12V (gk) 〉=Δ 12V (gk+1).The following describes the occasion (Fig. 5 (b) and (c)) that satisfies above-mentioned relation in all scopes of 0≤gk≤n.

The various relations of the effective voltage V2 that adds on effective voltage V1 that Fig. 5 (a) and (b), (c) and (d) being illustrated in adds on the liquid crystal layer of the plain 10a of secondary image of pixel 10 shown in Figure 1 and the liquid crystal layer of the plain 10b of secondary image.

Voltage shown in Fig. 5 (a) adds condition A and add same voltage (V1=V2) on the liquid crystal layer of plain 10a of two secondary images and 10b.That is Δ V12 (gk)=0 (volt).

Voltage conditions B shown in Fig. 5 (b) is V1＞V2, and Δ V12 does not change maintenance necessarily with V1.That is voltage conditions B is about any gray shade scale, and gk satisfies the relation of Δ V12 (gk)=Δ V12 (gk+1).Get Δ V12 (gk)=1.5 (volt) as typical value in the present embodiment, but much less also can get the value beyond this.The value of Δ V12 (gk) is big, and effect of the present invention increases, the problem that the brightness (transmissivity) when white the demonstration still arranged reduces.Further, the value of Δ V12 (gk) is than the big words of threshold voltage (that is Vth shown in Fig. 4 (b)) of the voltage dependency characteristic that adds of the transmissivity of liquid crystal indicator, because the brightness (transmissivity) in the time of black the demonstration can occurring increases, the problem that the contrast of display degree reduces can make Δ V12 (gk)≤Vth.

Voltage conditions C shown in Fig. 5 (c) is V1＞V2, and Δ V12 reduces with the V1 increase.That is voltage conditions C is about any gray shade scale, and gk satisfies the relation of Δ V12 (gk)＞Δ V12 (gk+1).

Get Δ V12 (0)=1.5 (volt), Δ V12 (n)=0 (volt) as typical value in the present embodiment, but much less also can get the value beyond this.But the viewpoint of the demonstration contrast during from above-mentioned such obliquely view can make Δ V12 (gk)≤Vth, and the viewpoint of the brightness during from white the demonstration can make Δ V12 (gk)=0 (volt).

Voltage conditions D shown in Fig. 5 (d) is V1＞V2, and Δ V12 increases with V1.That is voltage conditions D is about any gray shade scale, and gk becomes Δ V12 (gk)＜Δ V12 (gk+1).

Get Δ V12 (0)=0 (volt), Δ V12 (n)=1.5 (volt) as typical value in the present embodiment.

In liquid crystal indicator 100 according to an embodiment of the invention, impressed voltage on the liquid crystal layer of plain 10a of secondary image and 10b satisfies voltage conditions B or voltage conditions C.In addition, at Fig. 5 (b) with (c), all satisfying the condition of Δ V12＞0 on the gray shade scale, but under only gray shade scale and the highest gray shade scale, also can make Δ V12=0.

The limit is with reference to figure 6, and limit explanation difference working voltage condition A is to the scale grade characteristic of the liquid crystal indicator of the MVA mode of the occasion of D.Fig. 6 (a) and transverse axis (b) are (positive field angle standardization transmissivity ÷ 100) ^ (1/2.2), (a) the longitudinal axis is (right 60 degree visual angle standardization transmissivity ÷ 100) ^ (1/2.2), and the longitudinal axis (b) is (upper right 60 degree visual angle standardization transmissivity ÷ 100) ^ (1/2.2).In addition for reference to for the purpose of, draw the straight line of the characteristic of expression during top view in the lump.

Voltage conditions A is same for the liquid crystal indicator of the prior art represented among the occasion that adds same voltage (that is Δ V12 (gk)=0) on the liquid crystal layer of plain 10a of secondary image and 10b and Fig. 4, γ characteristic such as Fig. 6 (a) and (b) be shown with big skew.

In addition, voltage conditions D than the view angle dependency of the γ characteristic of voltage conditions B and C to improve effect little.Voltage conditions D corresponding for example opens voltage conditions under the pixel segmentation that the electric capacity of record in the flat 6-332009 communique etc., use prior art cuts apart the spy, effect with the viewing angle characteristic in the liquid crystal indicator that improves normal white mode, even adopt voltage conditions D in the liquid crystal indicator of normal black formula, the effect of the view angle dependency of reduction γ characteristic is very little.

As mentioned above, the view angle dependency for the γ characteristic in the liquid crystal indicator that reduces normal black formula can adopt voltage conditions B or C.

Below, the difference that the limit is made clear when showing with reference to figure 7 limits that is caused because of the voltage conditions of transmissivity when adding the highest grayscale voltage.

In any one occasion of voltage conditions B or D, the transmissivity when showing in vain is lower than adopting voltage conditions A certainly.Transmissivity during white show of voltage conditions C is identical with the occasion of employing voltage conditions A, and in this point, voltage conditions C goes with D than voltage conditions B.Therefore, the transmissivity when considering the field angle dependence of γ characteristic and showing in vain we can say that voltage conditions C is excellent.

The following describes the condition of the area ratio that satisfies the secondary image element.

In the present invention, secondary image plain SP1, SP2 ..., SPn liquid crystal layer on the effective voltage that adds be V1, V2 ..., Vn, the area of each secondary image element be SSP1, SSP2 ..., SSPn, and have V1＞V2＞... during the concerning of＞Vn, SSP1≤SSPn is arranged preferably.The following describes this point.

Fig. 8 represents that the area of the secondary image in the pixel 10 shown in Figure 1 plain 10a, 10b gets SSP1, SSP2, its area ratio and be (SSP1: SSP2)=(1: 3), the comparison of the occasion γ characteristic of (1: 2), (1: 1), (2: 1), (3: 1).In addition, use above-mentioned voltage conditions C about voltage conditions.The γ characteristic of Fig. 8 (a) expression right, Fig. 8 (b) expression upper right side to the γ characteristic.In addition, be illustrated in positive transmissivity under each ratio of division among Fig. 9.

As can be seen from Figure 8, the area that makes the high secondary image element (10a) of impressed voltage is than more little, and the effect of view angle dependency of improving the γ characteristic is high more.

The viewpoint of the transmissivity during from white the demonstration, area ratio (SSP1: get maximal value in the time of SSP2)=(1: 1), reduce than unequal with area.Its reason is unequal with the area ratio, and either party area of secondary image element of the plain or second secondary image element of first secondary image diminishes, and therefore can not obtain good MVA orientation.In addition, this fact is very remarkable in the little high-resolution liquid crystal display device of elemental area.That is area ratio can be (1: 1), but consider the γ characteristic view angle dependency improve effect and white the demonstration time transmissivity, also can suitably adjust according to the purposes of liquid crystal indicator etc.

The following describes the number of cutting apart of pixel.

In the liquid crystal indicator 100 that Fig. 1 represents, and the secondary image element of 1 pixel 10 of formation (10a, number 10b) is 2, but the invention is not restricted to this, secondary image prime number order also can be more than 3.

The number of Figure 10 vice pixel is in 2 and 4 s' occasion and do not cut apart the γ characteristic of the occasion of pixel.The γ characteristic of Figure 10 (a) expression right, Figure 10 (b) expression upper right side to the γ characteristic.Transmissivity when in addition, Figure 11 represents white demonstration of respectively corresponding liquid crystal indicator.In addition, the area of each pixel is identical, and voltage conditions is got B.

As can be seen from Figure 10, along with secondary image prime number purpose increases, the effect of improving the side-play amount of γ characteristic becomes big.Compare with the occasion of not cutting apart pixel especially, be appreciated that that secondary image prime number order is changed over two the effect of occasion is remarkable.Further, be increased to 4 by making the pixel segmentation number from 2, the side-play amount that becomes the γ characteristic does not have big-difference, becomes level and smooth good characteristic for the variation of the side-play amount of the variation of display gray scale grade.But,, cut apart transmissivity (front) reduction more when how white number is more shows as can be seen from Figure 11.Cutting apart number from 2 occasions that are increased to 4 especially, the reduction of the transmissivity when showing in vain is remarkable.This significantly reduced main reason is narrated as the front, is the significantly reduced cause of area of 1 secondary image element.Not having the occasion cut apart and cutting apart number is that the main reason that the transmissivity under 2 the occasion reduces is because employing voltage conditions B.That is consider the γ characteristic view angle dependency improve effect and white the demonstration time transmissivity, according to the purposes of liquid crystal indicator etc., can suitably adjust and cut apart number.

Be appreciated that to follow and cut apart several increases that the distortion of the side-play amount of γ characteristic and skew shape reduces, and can improve the view angle dependency of γ characteristic from above result.In addition, it is the most remarkable that to see what improve effect be that the occasion of no pixel segmentation becomes 2 occasion (secondary image prime number order is 2 a occasion) poor with pixel segmentation, transmissivity when considering to follow secondary image prime number purpose to increase white the demonstration reduces and the throughput rate reduction, the number of secondary image element preferably 2.

In liquid crystal indicator 100 shown in Figure 1, be connected independently TFT16a and TFT16b respectively on the plain 10a of each secondary image and the 10b, the source electrode of TFT16a, TFT16b connects signal lines 14a and 14b respectively.Therefore, in liquid crystal indicator 100, any effective voltage is opposite with adding on the liquid crystal layer of a plurality of secondary image elements, signal wire (14a, number 14b) become prior art shown in Figure 3 liquid crystal indicator 100 ' in 2 times of number of signal wire 14, the number of signal-line driving circuit also must be 2 times.

To this, the liquid crystal indicator of another suitable embodiment according to the present invention that below will illustrate has liquid crystal indicator 100 with prior art, and ' identical line number signal can add different effective voltage mutually under the condition of similar above-mentioned voltage conditions C on the liquid crystal layer of plain 10a of secondary image and 10b.

The electrical structure of Figure 12 representation of concept liquid crystal indicator 200 according to another embodiment of the invention.Represent to have and the inscape of liquid crystal indicator shown in Figure 1 100 inscape of identical functions in fact with common reference symbol, omit its explanation here.

Pixel 10 is divided into secondary image plain 10a, 10b, and secondary image plain 10a, 10b connect TFT16a, TFT16b and auxiliary capacitor (CS) 22a, 22b respectively.The grid of TFT16a and TFT16b is connected sweep trace 12, and source electrode connects common (same) signal wire 14. Auxiliary capacitor 22a, 22b connect respectively auxiliary capacitor distribution (CS bus) 24a and auxiliary capacitor distribution 24b. auxiliary capacitor 22a and 22b by the auxiliary capacitance electrode that is connected electrically to sub-pixel electrode 18a and 18b respectively, be connected electrically to auxiliary capacitor distribution 24a and 24b the auxiliary capacitor opposite electrode and during the insulation course (not shown) that is provided with form.The auxiliary capacitor opposite electrode of auxiliary capacitor 22a and 22b is independent mutually, has the structure that can supply with the different mutually opposed voltage of auxiliary capacitor from each auxiliary capacitor distribution 24a and 24b.

Can add the principle of different mutually effective voltages below to the liquid crystal layer of plain 10a of two secondary images of liquid crystal indicator 200 and 10b with the figure explanation.

The equivalent electrical circuit of 1 pixel of Figure 13 representation of concept liquid crystal indicator 200.In electrical equivalent circuit, the liquid crystal layer of plain 10a of each secondary image and 10b is represented with liquid crystal layer 13a and 13b.In addition, the liquid crystal capacitance that is formed by sub-pixel electrode 18a and 18b, liquid crystal layer 13a and 13b and opposite electrode 17 (common for plain 10a of secondary image and 10b) is as C1ca, C1cb.

The electrostatic capacitance value that makes liquid crystal capacitance C1ca and C1cb is same value CLC (V).The value of CLC (V) depends on the effective voltage (V) that adds on the liquid crystal layer of plain 10a of secondary image and 10b.In addition, the auxiliary capacitor 22a of difference separate connection and 22b are as Ccsa, Ccsb on the liquid crystal capacitance of plain 10a of each secondary image and 10b, and their electrostatic capacitance value is got unified value CCS.

The liquid crystal capacitance C1ca of the plain 10a of secondary image and the electrode of auxiliary capacitor Ccsa are connected to the drain electrode into the TTF16a that drives the plain 10a setting of secondary image, another electrode of liquid crystal capacitance C1ca connects opposite electrode, and another electrode of auxiliary capacitor Ccsa connects auxiliary capacitor distribution 24a.The liquid crystal capacitance C1cb of the plain 10b of secondary image and the electrode of auxiliary capacitor Cc sb are connected to the drain electrode into the TTF16b that drives the plain 10b setting of secondary image, another electrode of liquid crystal capacitance C1cb connects opposite electrode, and another electrode of auxiliary capacitor Ccsb connects auxiliary capacitor distribution 24b.The grid of TFT16a and TFT16b all is connected to sweep trace 12, and source electrode is connected to arbitrary signal wire 14.

The timing of each voltage when Figure 14 (a) ~ (f) representation of concept drives liquid crystal indicator 200 of the present invention.

The voltage waveform Vs of Figure 14 (a) expression signal wire 14, the voltage waveform Vcsa of Figure 14 (b) expression auxiliary capacitor distribution 24a, the voltage waveform Vcsb of Figure 14 (c) expression auxiliary capacitor distribution 24b, the voltage waveform Vg of Figure 14 (d) expression sweep trace 12, the voltage waveform V1ca of the pixel electrode 18a of Figure 14 (e) vice pixel 10a, the voltage waveform V1cb of the pixel electrode 18b of Figure 14 (f) vice pixel 10b.In addition, the dotted line among the figure is represented the voltage waveform COMMON (Vcom) of opposite electrode 17.

Use the operation of the equivalent electrical circuit of Figure 14 (a) ~ (f) explanation Figure 13 below.

Change to VgH by voltage from VgL at the Vg of moment T1, TFT16a and TFT16b conducting (on-state) simultaneously, the voltage Vs of signal wire 14 is transferred to sub-pixel electrode 18a, the 18b of plain 10a, 10b of secondary image, to plain 10a, the 10b charging of secondary image.Equally, auxiliary capacitor Csa, the Csb of each secondary image element also charge from signal wire.

Then, along with the voltage Vg of sweep trace 12 when the moment T2 changes to VgL from VgH, TFT16a and TFT16b become nonconducting state (off-state) simultaneously, secondary image plain 10a, 10b, auxiliary capacitor Csa, Csb all with signal wire 14 electrical isolations.And then soon, because the introducing phenomenon that the influences such as stray capacitance that TFT16a, TFT16b have cause, voltage V1ca, the V1cb of each sub-pixel electrode approximately reduces same voltage Vd after this, for

V1ca＝Vs-Vd

V1cb＝Vs-Vd。

In addition, voltage Vcsa, the Vcsb of each auxiliary capacitor distribution are at this moment

Vcsa＝Vcom-Vad

Vcsb＝Vcom+Vad。

At moment T3, the voltage Vcsa that connects the auxiliary capacitor distribution 24a of auxiliary capacitor Csa changes to Vcom+Vad from Vcom-Vad, and the voltage Vcsb that connects the auxiliary capacitor distribution 24b of auxiliary capacitor Csb changes to Vcom-Vad from Vcom+Vad, changes 2 times Vad.Follow the voltage of auxiliary capacitor distribution 24a and 24b, voltage V1ca, the V1cb of each sub-pixel electrode are changed to

V1ca＝Vs-Vd+2×K×Vad

V1cb＝Vs-Vd-2×K×Vad。

But, K=CCS/ (CLC (V)+CCS).

At moment T4, Vcsa changes to Vcom-Vad from Vcom+Vad, and Vcsb changes to Vcom+Vad from Vcom-Vad, changes 2 times Vad, V1ca, V1cb from

V1ca＝Vs-Vd+2×K×Vad

V1cb＝Vs-Vd-2×K×Vad

Change to

V1ca＝Vs-Vd

V1cb＝Vs-Vd。

At moment T5, Vcsa changes to Vcom+Vad from Vcom-Vad, and Vcsb changes to Vcom-Vad from Vcom+Vad, changes 2 times Vad, V1ca, V1cb also from

V1ca＝Vs-Vd

V1cb＝Vs-Vd

Change to

V1ca＝Vs-Vd+2×K×Vad

V1cb＝Vs-Vd-2×K×Vad。

Vcsa, Vcsb, V1ca, V1cb be at the interval of the integral multiple of each level write time 1H, the variation of the above-mentioned T4 of alternate repetition, T5.Above-mentioned T4, T5 be at interval repeatedly 1 times, 2 times, 3 times of 1H or more than, can suitably set according to the driving method (polar inversion method etc.) and the show state (flicker, the harsh feeling of demonstration etc.) of liquid crystal indicator.This repeatedly when rewriting next pixel 10, that is to and time of T1 equivalence continue.Therefore, the voltage V1ca of each sub-pixel electrode, the effective value of V1cb become

V1ca＝Vs-Vd+K×Vad

V1cb＝Vs-Vd-K×Vad。

Therefore, effective voltage V1, the V2 that adds on the liquid crystal layer 13a of secondary image plain 10a, 10b and 13b is

V1＝V1ca-Vcom

V2＝V1cb-Vcom。

Also be

V1＝Vs-Vd+K×Vad-Vcom

V2＝Vs-Vd-K×Vad-Vcom。

Therefore, the poor Δ V12 of the effective voltage that on each the liquid crystal layer 13a of plain 10a of secondary image and 10b and 13b, adds (=V1-V2) (still, K=CCS/ (CLC (V)+CCS)) can add mutual different voltage for Δ V12=2 * K * Vad.

The V1 from Figure 12 to Figure 14 of Figure 15 representation of concept present embodiment and the relation of V2.

Be appreciated that the liquid crystal indicator 200 of present embodiment that from Figure 15 the value of V1 is more little and Δ V12 value is big more, similar previously described voltage conditions C.In addition, the value of Δ V12 relies on V1 or V2 changes, and this is because the electrostatic capacitance value CLC (V) of liquid crystal capacitance has the cause of voltage-dependent.

Figure 16 represents the γ characteristic of the liquid crystal indicator 200 of present embodiment.For comparison purpose, be also illustrated in the γ characteristic that adds the occasion of same voltage on plain 10a of secondary image and the 10b among Figure 16.The liquid crystal indicator that can understand present embodiment from Figure 16 has also improved the γ characteristic.

Here, according to embodiments of the invention, the liquid crystal indicator that expression can improve normal black formula is the γ characteristic of the liquid crystal indicator of MVA mode particularly, but the invention is not restricted to this, also goes for the liquid crystal indicator of IPS mode.

The following describes the liquid crystal indicator of embodiment according to a second aspect of the invention.

The following describes and may suppress the suitable example that each pixel presents mutually different " flicker " of liquid crystal indicator brightness, that have at least 2 secondary image elements in demonstration under certain middle gray grade show state pixel is arranged (the plain arrangement of secondary image) or driving method, described.Here, liquid crystal indicator with pixel segmentation structure with above-mentioned embodiment according to a first aspect of the invention is the structure and the operation of the liquid crystal indicator of example explanation present embodiment, but arrange the method that the effect that obtains is not limited to pixel segmentation according to pixel, also can be suitable for liquid crystal indicator with other pixel segmentation structure.

The problem of " flicker " in the liquid crystal indicator at first is described.

In typical liquid crystal indicator, from the viewpoint of integrity problem, the voltage that adds on the liquid crystal layer of pixel is set at alternating voltage (claiming " AC driving method " sometimes).That is to say that set the magnitude relationship of the current potential of pixel electrode and opposite electrode and reverse at each certain hour, the direction of the electric field that adds (direction of line of electric force) is in each counter-rotating of fixing time on liquid crystal layer.In the typical liquid crystal indicator that opposite electrode and pixel electrode is arranged on the different substrates, the direction of the electric field that adds on the liquid crystal layer is reversed to observer's side with from observer's lateral light source from light source side.

The cycle of the direction counter-rotating of the electric field that adds on the liquid crystal layer is typically 2 times (for example 33.333ms) of image duration (for example 16.667ms).That is to say, in liquid crystal indicator, be added to the direction counter-rotating of the electric field on the liquid crystal layer during every demonstration 1 width of cloth image (two field picture).Therefore, showing the occasion of rest image, the direction of each electric field can not be correctly consistent with electric field intensity (impressed voltage), that is the words of direction of an electric field electric field intensity variation when at every turn changing, follow electric field intensity to change pixel intensity and change, the problem of flicker takes place to show.

For preventing this flicker, must make the electric field intensity (impressed voltage) of the direction of each electric field correctly consistent.But, in industrial liquid crystal indicator, correctly unanimity is very difficult because make electric field intensity about each direction of an electric field, therefore by making the pixel that has mutual different directions of an electric field in the viewing area in abutting connection with configuration, by utilizing the spatially average effect of pixel intensity, reduce flicker.This method is commonly referred to as " some counter-rotating " or " line counter-rotating ".In addition, in this " inversion driving ", the pixel period of counter-rotating not only has (counter-rotating of 1 line) of the counter-rotating (counter-rotating of each row) of (1 counter-rotating) of counter-rotating (reversal of poles of each row and each row) of the alternate chequer shape of height in 1 pixel unit or 1 row shape, and per two row and the reversal of poles of each row various forms such as (the 1 row point counter-rotatings of 2 row) are arranged, can suitably set as required.

As mentioned above, for realizing high-quality display, preferably to satisfy following three conditions: each AC driving of fixing time, for example reversing per image duration of the direction of the voltage that 1. on liquid crystal layer, adds, 2. make voltage (the perhaps quantity of electric charge of liquid crystal capacitance charging) that in the direction of each electric field, on liquid crystal layer, adds and the quantity of electric charge that is charged to auxiliary capacitor consistent as far as possible, 3. in the vertical-scan period (for example image duration), the different pixel of the direction of the electric field that adds on liquid crystal layer (being also referred to as " polarity of voltage " sometimes) is in abutting connection with configuration.In addition, so-called " vertical-scan period " be defined as select certain sweep trace to next time select this sweep trace during.1 vertical-scan period is 1 image duration under no interlacing drives, and corresponding interlacing drives during following 1 filtering.In addition, in each vertical-scan period, select the moment of a certain sweep trace and select next sweep trace the moment poor (during) be called 1 horizontal scanning period.

Liquid crystal indicator according to the embodiment of the invention described above becomes at least two secondary image elements to 1 pixel segmentation, and actively makes brightness (transmissivity) difference of these secondary image elements, realizes the good demonstration of field angle characteristic.The result of inventor's research, the occasion 1 pixel segmentation being become to present a plurality of secondary image elements of different brightness is preferably in and adds the 4th condition that satisfies about the configuration of secondary image element on above-mentioned three conditions.Specifically, the brightness order (order of brightness magnitude relationship) that preferably actively makes the different secondary image element of brightness random arrangement as far as possible.Show that best is the secondary image element that the brightness order the equates configuration that do not adjoin each other on column direction and line direction.What in other words, demonstration was best is that the best secondary image element that the brightness order is equated is with the alternate chequer shape configuration of height.

The following describes the driving method that the liquid crystal indicator according to the embodiment of the invention described above is fit to and the arrangement of pixel arrangement and secondary image element.

The example of driving method of the liquid crystal indicator of embodiments of the invention is described below with reference to Figure 17 and Figure 18.

In the following description, as shown in figure 17, illustrate with have multirow (1 ~ rp) and multiple row (1 ~ cq) matrix shape arrange, each pixel P (p, q) (but 1≤p≤rp, 1≤q≤cq) have the plain SPa of two secondary images (p, q) and SPb (p, example q).Figure 17 is signal wire S-C1, S-C2, S-C3, the S-C4 of the liquid crystal indicator of representation of concept present embodiment ... S-Ccq, sweep trace G-L1, G-L2, G-L3 ... G-Lrp and auxiliary capacitor distribution CS-A and CS-B, each pixel P (p, q) and constitute the plain SPa (p of secondary image of each pixel, q) and SPb (p, q) the relative concept map of the part of configuration (8 row, 6 row).

As shown in figure 17,1 pixel P (p, q) near the sweep trace G-Lp level connects pixel central authorities have up and down the plain SPa of secondary image (p, q) and SPb (p, q).That is to say, the plain SPa of secondary image (p, q) and SPb (p q) arranges with column direction in each pixel.The plain SPa of each secondary image (p, q) and SPb (p, the auxiliary capacitor distribution CS-A or the CS-B of side's (not shown) connection adjacency of auxiliary capacitance electrode q).In addition, at each pixel P (p, q) the signal wire S-Cq that goes up the signal voltage of supplying with corresponding display image becomes the formation of supplying with signal voltage on the TFT element (not shown) that the right adjacent secondary image element (pixel) of each signal wire has separately as being provided with on the picture with vertical between each pixel (column direction) extends.In structure shown in Figure 17 is that an auxiliary capacitor distribution or a sweep trace are made of plain the having of two secondary images, has and can improve the advantage that pixel is opened rate.

Figure 18 (a) ~ (j) is expressed as the waveform of the various voltages (signal) that drive the liquid crystal indicator with structure shown in Figure 17.Have the liquid crystal indicator that the driven of the voltage waveform of Figure 18 (a) ~ (j) has the structure of Figure 17 by use, can satisfy above-mentioned 4 conditions.

Above-mentioned 4 these facts of condition are satisfied in explanation in the liquid crystal indicator of present embodiment below.In the following description, be purposes of simplicity of explanation, represent that whole pixels show the state of a certain middle gray grade

Signal wire S-C1 is supplied with in Figure 18 (a) expression, S-C3, S-C5 ... the shows signal voltage waveform of (signal line group of odd indexed is also referred to as S-O sometimes) (source signal voltage waveform), signal wire S-C2 is supplied with in Figure 18 (b) expression, S-C4, S-C6 ... the shows signal voltage waveform of (signal line group of even number sequence number is also referred to as S-E sometimes), the opposed voltage waveform of auxiliary capacitor of auxiliary capacitor distribution CS-A is supplied with in Figure 18 (c) expression, the opposed voltage waveform of auxiliary capacitor of auxiliary capacitor distribution CS-B is supplied with in Figure 18 (d) expression, the scanning voltage waveform of sweep trace G-L1 is supplied with in Figure 18 (e) expression, the scanning voltage waveform of sweep trace G-L2 is supplied with in Figure 18 (f) expression, the scanning voltage waveform of sweep trace G-L3 is supplied with in Figure 18 (g) expression, the scanning voltage waveform of sweep trace G-L4 is supplied with in Figure 18 (h) expression, the scanning voltage waveform of sweep trace G-L5 is supplied with in Figure 18 (i) expression, and the scanning voltage waveform of sweep trace G-L6 is supplied with in Figure 18 (j) expression.The voltage of a certain sweep trace switch to from zero level (VgL) high level (VgH) constantly play sweep trace voltage next time switch to from VgL VgH constantly during be 1 horizontal scanning period (1H).In addition, the voltage of each sweep trace become high level during be also referred to as during the selection.

Show the occasion of certain middle gray grade because represent whole pixels here, thus Figure 18 (a) and (b) the shows signal voltage of expression to become all be the vibrational waveform of fixed amplitude.In addition, the vibration period of shows signal voltage is got 2 horizontal scanning periods (2H).Shows signal voltage fluctuation, and signal wire S-O (S-C1, S-C3 ...) voltage waveform and signal wire S-E (S-C2, S-C4 ...) phase place phase mutual deviation 180 degree of voltage waveform, be owing to satisfy above-mentioned 3 conditions.Generally, in TFT drives, the voltage of signal wire is changed by the influence of the variation of scanning voltage waveform can when pixel electrode transmits by the TFT element phenomenon (be also referred to as sometimes and introduce phenomenon).Here, the setting of opposed voltage will be considered this introducing phenomenon, the voltage waveform approximate center value of voltage waveform after being transferred to pixel electrode with signal wire set like that, the signal voltage extra token corresponding in Figure 18 (a) and (b) with the voltage waveform of the pixel electrode voltage higher than opposed voltage+, the signal voltage extra token corresponding with the voltage waveform of the pixel electrode voltage lower than opposed voltage-.This+,-the mark correspondence is added to the direction of the electric field on the liquid crystal layer, with+and-be reversed in the direction of the electric field that adds on each liquid crystal layer.

As earlier in respect of figures 12～Figure 15 explanation, the TFT that connects with this sweep trace when the scanning voltage of certain sweep trace is VgH is on-state, supplies with corresponding shows signal voltage at the secondary image element that connects this TFT.Subsequently, because the opposed change in voltage of auxiliary capacitor after the voltage of sweep trace becomes VgL, and the changing value of the opposed voltage of this auxiliary capacitor (containing change direction, the symbol of variable quantity) is plain different mutually to two secondary images, so the effective voltage that is added on the secondary image element changes.

As Figure 18 (c) with (d), here, the amplitude of the vibration of the opposed voltage of auxiliary capacitor of auxiliary capacitor distribution CS-A and CS-B and cycle are for example 2 times (with reference to Figure 14) and the 1H of Vad of same value simultaneously, and either party phase shifting 180 of vibrational waveform of CS-A, CS-B is consistent with the opposing party's vibrational waveform when spending.That is to say that phase place only is offset 0.5H.The average voltage of each sub-pixel electrode, after the voltage of corresponding scanning line changes to VgL from VgH, the occasion that increases in the change in voltage of the auxiliary capacitor distribution of correspondence, the shows signal voltage of the signal lines of the voltage ratio of corresponding scanning line when VgH increases, in the occasion that the initial change in voltage of the auxiliary capacitor distribution of correspondence reduces, the shows signal voltage of the signal lines of the voltage ratio of corresponding scanning line when VgH reduces.

The result, to Figure 18 (a) and the additional mark of the shows signal voltage (b) be+time, above-mentioned change in voltage at the auxiliary capacitor distribution is the occasion that increases direction, and the effective voltage ratio that is added on the liquid crystal layer is to reduce the occasion height of direction in above-mentioned change in voltage.On the other hand, to Figure 18 (a) and the additional mark of the shows signal voltage (b) be-time, above-mentioned change in voltage at the auxiliary capacitor distribution is the occasion that increases direction, and the effective voltage that is added on the liquid crystal layer is lower than the occasion that in above-mentioned change in voltage is the minimizing direction.

In Figure 17, express (here being image duration) each pixel P of a certain vertical-scan period (p, q) and the plain SPa of secondary image (p, q) and SPb (p, state q).Put down in writing following 3 marks of the plain corresponding scanning line of each secondary image according to symmetry, represent the state of each secondary image element.

The magnitude relationship of effective impressed voltage of first mark H or L vice pixel, mark H represents effective impressed voltage height, mark L represents that effective impressed voltage is low.Second mark+or-magnitude relationship of expression opposite electrode and sub-pixel electrode, that is be added to the direction of the electric field on the liquid crystal layer of each sub-pixel electrode, the voltage height of the voltage ratio opposite electrode of mark+vice pixel electrode, the voltage of the voltage ratio opposite electrode of mark-vice pixel electrode is low.The 3rd mark A or B represent that each corresponding auxiliary capacitor distribution is CS-A or CS-B.

For example, please see the plain Spa (1,1) of secondary image of pixel P (1,1) and the state of Spb (1,1).Can understand from Figure 18 (a) with (e), the shows signal voltage of (VgH period P S) is "+" during selecting GL-1.In addition, the voltage of the auxiliary capacitor distribution of correspondence each the secondary image element of the scanning voltage of GL-1 when VgH changes to VgL is in 18 (c) and the state of the position of arrow (first arrow from the left side) expression (d).Therefore, the initial change in voltage of the opposed voltage of auxiliary capacitor of the Spa (1,1) after the scanning voltage of GL-1 changes to VgL from VgH increases (it is represented as " U ") as can understanding from Figure 18 (c).On the one hand, the initial change in voltage of the opposed voltage of auxiliary capacitor after the scanning voltage of GL-1 changes to VgL from VgH, Spb (1,1) reduces as can understanding from Figure 18 (c) (with it as D1 " expression), as from Figure 18 (d).Therefore, the effective voltage of Spa (1,1) increases, and the effective voltage of Spb (1,1) reduces.So effective impressed voltage of Spa (1,1) is bigger than the change of Spb (1,1), go up remarks mark H at Spa (1,1), go up remarks mark L at Spb (1,1).

According to Figure 18 (b), in the SPa (1,2) and SPb (1,2) of P (1,2), the shows signal voltage during the selection GL-1 is "-".In addition, the voltage of the scanning voltage of GL-1 auxiliary capacitor distribution when VgH changes to VgL, corresponding each secondary image element be in 18 (c) and (d) the state of position shown in the arrow (from first arrow of a left side).Therefore, the initial change in voltage of the opposed voltage of auxiliary capacitor after the scanning voltage of GL-1 changes to VgL from VgH, SPa (1,2) increases (" U ") as can understanding from Figure 18 (c).On the one hand, the initial change in voltage of the opposed voltage of auxiliary capacitor after the scanning voltage of GL-1 changes to VgL from VgH, Spb (1,2) reduces (" D ") as can understanding from Figure 18 (d), shown in.Therefore, the effective voltage of Spa (1,2) reduces, and the effective voltage of Spb (1,2) increases.So effective impressed voltage of Spa (1,2) diminishes than Spb's (1,2), go up remarks mark L at Spa (1,2), go up remarks mark H at Spb (1,2).

Further, according to Figure 18 (a), in the SPa (2,1) and SPb (2,1) of P (2,1), the shows signal voltage during the selection GL-2 is "-".In addition, the voltage of the scanning voltage of GL-2 auxiliary capacitor distribution when VgH changes to VgL, corresponding each secondary image element be in 18 (c) and (d) the state of position shown in the arrow (from second arrow in a left side).Therefore, the initial change in voltage of the opposed voltage of auxiliary capacitor after the scanning voltage of GL-2 changes to VgL from VgH, SPa (2,1) reduces (" D ") as can understanding from Figure 18 (d).On the one hand, the initial change in voltage of the opposed voltage of auxiliary capacitor after the scanning voltage of GL-2 changes to VgL from VgH, Spb (2,1) increases (" U ") as can understanding from Figure 18 (c).Therefore, the effective voltage of Spa (2,1) increases, and (effective voltage of (2,1) reduces Spb.So effective impressed voltage of Spa (2,1) is bigger than Spb's (2,1), goes up remarks mark H at Spa (2,1), goes up remarks mark L at Spb (2,1).Like this, can understand the state that can obtain each secondary image element shown in Figure 17.

The liquid crystal indicator of present embodiment can satisfy first condition and drive.

Because Figure 17 and Figure 18 represent the state in a certain image duration, therefore can not whether satisfy first condition from these figure evaluations, but, for example, then can carry out making the direction that is added to the electric field on the liquid crystal layer AC driving in each counter-rotating image duration by 180 degree that the phase place of the voltage waveform of each signal wire (S-0 (Figure 18 (a)) or S-E (Figure 18 (b))) in the next frame of frame shown in Figure 180 is misplaced respectively.

Further, in the liquid crystal indicator of present embodiment, relation for effective impressed voltage size of making each the secondary image element in each pixel, in other words, configuration in the display frame of the brightness size sequence of secondary image element (the position relation of mark among Figure 17 " H " and " L ") does not change in every frame, the dislocation of the phase place of the voltage waveform of accompaniment signal line, the phase place of the voltage waveform of auxiliary capacitor distribution CS-A and CS-B also misplace 180 the degree.Like this, the state of the replacement mark "+" of realization Figure 17 and mark "-" (for example, in the next frame shown in Figure 17

Like this, can satisfy above-mentioned first condition.

Discuss whether satisfy second condition below, that is give the quantity of electric charge of liquid crystal layer (with the auxiliary capacitor of corresponding each secondary image element) charging of each secondary image element whether consistent in the direction of each electric field.Here, in the liquid crystal indicator of present embodiment, each pixel has to the different secondary image element of effective impressed voltage of liquid crystal layer, but owing to show that in what is called it is the high secondary image element of brightness order that flicker is given sex with domination to display quality, that is the secondary image element of remarks mark " H " among Figure 17, therefore add second condition for the secondary image element of remarks mark " H " especially.

About second condition, with reference to each voltage waveform explanation shown in Figure 180.

Giving the liquid crystal capacitance of secondary image element and auxiliary capacitor charging, the voltage that is corresponding scanning line is (selecting period P S) during the VgH.In addition, give the shows signal voltage that the quantity of electric charge of liquid crystal electric capacity charging relies on the signal wire during the selection and the voltage difference of opposed voltage (not shown among Figure 18), rely on the voltage difference of the voltage (the opposed voltage of auxiliary capacitor) of the shows signal voltage of signal wire during the selection and auxiliary capacitor distribution to the quantity of electric charge of auxiliary capacitor charging.

As Figure 18 (a) with (b), the shows signal voltage of the signal wire during each is selected, deposit remarks in the drawings+or-two kinds of voltages of mark, but no matter in which kind of occasion, do not have change in voltage in during selecting.In addition, not representing opposed voltage among the figure, but here, is same voltage to all secondary image elements, and is the indeclinable DC voltage of voltage in time.

There are two kinds of CS-A and CS-B in the auxiliary capacitor distribution.The voltage waveform of CS-A also is same waveform during the selection of any one sweep trace.Similarly, the voltage waveform of CS-B also is same waveform during the selection of any one sweep trace.That is flip-flop (DC level) value of the voltage of auxiliary capacitor distribution also is same value during the selection of one scan line in office.

Therefore, the flip-flop (DC level) of the voltage of the shows signal voltage by suitable each signal wire of setting, the voltage of opposite electrode and each auxiliary capacitor distribution can satisfy second condition.

Discuss below and whether satisfy the 3rd condition, that is whether adjacency disposes in the different pixel of each polarity image duration.But, in the liquid crystal indicator of present embodiment because each pixel has to the different secondary image element of effective impressed voltage of liquid crystal layer, therefore about pixel except requiring the 3rd condition, the secondary image element identical to effective impressed voltage also requires the 3rd condition.Especially, identical with the occasion of above-mentioned second condition, for the high secondary image element of brightness order, that is the secondary image element of remarks mark " H " among Figure 17, it is important satisfying the 3rd condition.

As shown in figure 17, the mark "+" and "-" that represent each pixel polarity (direction of electric field), line direction (horizontal direction) for example with (+,-), (+,-), (+,-) and 2 pixels (2 row) periodic reversal, on column direction (vertical direction) for example also with (+,-), (+,-), (+,-), (+,-) and 2 pixels (2 row) periodic reversal.That is to say, see, present the state that is called a counter-rotating, satisfy the 3rd condition with pixel unit.

Confirm the high secondary image element of brightness order below, that is the secondary image element of remarks mark " H " among Figure 17.

On line direction, when for example seeing the Spa of first row, can't see+H as shown in figure 17, ,+H ,+reversal of poles of H, but on column direction, for example saw for first when row, with (+H ,-H), (+H,-H), (+H ,-H), (+H ,-H) and 2 pixels (2 row) cycle reversal of poles.That is to say, see, present the state that is called the line counter-rotating, satisfy the 3rd condition with the high secondary image primitive unit cell of brightness order of particular importance.The secondary image element of mark L satisfies the 3rd condition according to same rule configuration.

The 4th condition is discussed below, and the 4th condition is to make the configuration that do not adjoin each other as far as possible of the identical secondary image element of brightness order in actively making the different secondary image element of brightness.

In the present embodiment actively make the different secondary image element of brightness, that is the visibly different secondary image element of the effective impressed voltage that adds on liquid crystal layer is represented with mark H or L in Figure 17.

In Figure 17, add up to 4 secondary image primitive unit cells (for example Spa (1,1), Spb (1 if see 2 of 2 of line directions, column direction, 1), Spa (1,2), Spb (1,2)), with line direction H, L, change the secondary pixel group that delegation is configured to L, H and form the configuration that all is paved with.That is to say, in configuration shown in Figure 17, form the structure of the mark of H and L with the alternate chequer configuration of secondary image primitive unit cell height.Can understand and satisfy the 4th condition.

If this configuration of research pixel unit, the corresponding relation of the position in the arrangement of the plain column direction of the brightness size sequence of the secondary image element in each pixel and secondary image, changing (each pixel inversion here) with specified period in the pixel of going arbitrarily on line direction, is certain in the pixel that is listed as arbitrarily.That is to say, arbitrarily the pixel P of row (p presents the secondary image element (being the secondary image element with " H " expression) of maximum brightness in q) here, q be the words of the pixel of odd number be Spa (p, q), and q be the words of the pixel of even number be Spb (p, q).Certainly, conversely, q the pixel of odd number be Spb (p, q), and q the pixel of even number also can be Spa (p, q).On the one hand, any pixel P of row (p presents the secondary image element of maximum brightness in q), with p be that odd number or even number are irrelevant, in the same row be the plain Spa of same secondary image (p, q) or Spb (p, q).Here, get Spa (p, q) or Spb (p, q), be because for example in the odd column value of p no matter be even number or odd number, be Spa (p, q), the value of p in even column is no matter be even number or odd number, be Spb (p, q).

Like this, with reference to the liquid crystal indicator of the present embodiment of Figure 17 and Figure 18 explanation, because all satisfy above-mentioned 4 conditions, so can realize high-quality demonstration.

Liquid crystal indicator below with reference to Figure 19 another embodiment different with the driving method of secondary image element with 20 pixels illustrated.Figure 19 and Figure 20 from (a) to (j) respectively with Figure 17 and Figure 18 from (a) to (j) correspondence.

As from shown in Figure 20 (a) to (d), in the liquid crystal indicator of this embodiment, shows signal voltage, the every 2H vibration of the opposed voltage of auxiliary capacitor that is to say that the vibration period is 4H hour.In addition, signal wire S-O (the S-C1 of odd indexed, S-C3, S-C5 ...) and the signal wire S-E (S-C2 of even number sequence number, S-C4, S-C6 ...) the vibration phase of signal voltage differ 180 degree (2H time), the vibration phase of the voltage of auxiliary capacitor distribution CS-A and CS-B also differs 180 degree (2H time).Further, the phase place of the vibration of the voltage of signal wire S-O is for oscillation hysteresis 45 degree (1/8 cycle, that is H/2) of the voltage of auxiliary capacitor distribution CS-A.But phase differential of these 45 degree is not overlap setting with the moment of the change in voltage of auxiliary capacitance line constantly for the voltage that makes sweep trace changes to VgL from VgH, so can suitably setting of the value of being not limited thereto.

Even in the liquid crystal indicator of present embodiment, all pixels also are by actively making 2 different secondary image elements of brightness, constituting with the secondary image element of mark H or L mark.Moreover as shown in figure 19, the secondary image element of indicia H or L disposes like that with the alternate chequer of height, can satisfy the 4th condition equally with the foregoing description as can be known.In addition, about first condition,, can satisfy by employing and Figure 17, the same inverting method of the foregoing description illustrated in fig. 18.

But the embodiment that represents in Figure 19 and Figure 20 can not satisfy above-mentioned second condition.

Consider 1～4 pixel P (1,1), the P (2,1) that goes of first row of Figure 19, high secondary image plain Pa (1,1), Pa (2,1), Pa (3,1), the Pa (4,1) of brightness order of P (3,1), P (4,1).Pa (1,1) when charging, that is G-L1 polarity mark of signal lines when selection mode be+, during Pa (3,1) charging, that is G-L3 polarity mark of signal lines when selection mode be-.In addition, Pa (1, when 1) charging, that is the voltage waveform of G-L1 auxiliary capacitance line CS-A of correspondence when selection mode be during making selection approximate center the time be engraved in the waveform that the boundary step reduces, Pa (3,1) when charging, that is the voltage waveform of G-L3 auxiliary capacitance line CS-A of correspondence when selection mode be during making selection approximate center the time be engraved in the boundary step and increase waveform.Therefore, control the phase place of the voltage waveform signal of auxiliary capacitance line CS-B and sweep trace by precision, can make Pa (1,1) when charging and Pa (3, the DC level unanimity of the auxiliary capacitor opposite electrode when 1) charging, by this DC level is set at Pa (1, the voltage (identical) and the Pa (3 of the auxiliary capacitance electrode when 1) charging with the voltage of sub-pixel electrode, the average voltage of the voltage (identical) of the auxiliary capacitance electrode when 1) charging with the voltage of sub-pixel electrode, can make to Pa (1,1) and the charge volume unanimity of the electric charge of the auxiliary capacitor of Pa (3,1) charging.Then, note the words of Pa (2,1), during correspondence, that is G-L2 is when being in selection mode, and the polarity mark of signal lines is-(with above-mentioned Pa (3,1) identical), it is fixed value (not being vibrational waveform as described above) that the voltage of corresponding auxiliary capacitor does not change in time.Therefore, magnitude of voltage (said fixing value) and above-mentioned Pa (1,1), the Pa (3 of the auxiliary capacitance line by making corresponding Pa (2,1), 1) the DC level unanimity of representing in the explanation is removed Pa (1,1) and Pa (3,1) in addition, can make charge volume unanimity to the electric charge of the auxiliary capacitor of Pa (2,1).But, can understand that make charge volume and Pa (1,1), Pa (2,1) and Pa (3, the 1) unanimity to the electric charge of the auxiliary capacitor of Pa (4,1) this moment, because following reason is impossible.The polarity mark of the signal wire of corresponding Pa (4,1) is identical with Pa (1,1), and it is fixed value (not being vibrational waveform as described above) that the voltage of corresponding auxiliary capacitance line does not change in time.Therefore, the magnitude of voltage (said fixing value) of the auxiliary capacitor of corresponding Pa (4,1) is also identical with Pa (2,1), make and above-mentioned Pa (1,1), the DC level unanimity represented in the explanation of Pa (3,1), that is, need and corresponding Pa (4,1) and the magnitude of voltage of the auxiliary capacitance line of Pa (2,1) (said fixing value) unanimity, but this is impossible.Because, see that Figure 19 and Figure 20 just can understand, the auxiliary capacitor distribution of corresponding Pa (2,1) and Pa (4,1) all is CS-B, the voltage waveform of CS-B is rectangular-shaped vibrational waveform, during the selection of corresponding Pa (2,1), select the maximal value of vibrational waveform, at corresponding Pa (4,1) select the minimum value of vibrational waveform during the selection, so both voltages is inevitable different.

In addition, about as far as possible the identical secondary image element of polarity not in abutting connection with the 3rd condition of configuration, also poor than Figure 17 and previous embodiment shown in Figure 180.

In Figure 19, the situation of the reversal of poles of secondary image element that the voltage that adds on liquid crystal layer in the secondary image element of investigation formation pixel is obviously big that is the secondary image element of extra token H.As shown in figure 19, on line direction, for example see that the Spa of first row is capable, with+H ,+H ,+the H configuration, polarity nonreversible (this is identical with Figure 17).On column direction, for example see first row, with (+H ,-H ,-H ,+H), (+H ,-H ,-H ,+H) configuration, polarity is reversed with 4 pixel period.The cycle of the previous embodiment Semi-polarity counter-rotating of representing among Figure 17 and Figure 18 is 2 pixel period, with the 1/2 cycle reversal of poles in reversal of poles cycle of present embodiment.That is to say that the previous embodiment that represents among Figure 17 and Figure 18 is than the density reversal of poles of the present embodiment of representing among Figure 19 and Figure 20 with 2 times.In this point, present embodiment (embodiment that Figure 19 and Figure 20 represent) is poorer than the previous embodiment that represents among Figure 17 and Figure 18.

In fact, compare result displayed, can observe the difference on the display quality with the driving method of the last embodiment that realizes pixel arrangement shown in Figure 17 and the driving method of present embodiment shown in Figure 19.Specifically, the bigger display gray scale grade of luminance difference between the visibly different secondary image element of brightness, the occasion of for example representing 64/255 gray shade scale is observed the occasion that shows under the state that sight line is fixed, these two kinds of driving methods do not see that there were significant differences on showing.But the occasion of observing in mobile sight line in the occasion of the driving method of present embodiment (Figure 19), is observed the striped apperance of striation sometimes, and do not observe the problem of the striped apperance of striation in the driving method of last embodiment (Figure 17).This difference can think because above-mentioned reversal of poles cycle difference.Observe easily because the high secondary image of brightness is plain in 2 secondary image elements that comprise in each pixel, so the reversal of poles cycle of the high secondary image element of brightness is preferably as far as possible little.Here express the example that each pixel segmentation is become 2 secondary image elements, but in the occasion that is divided into more than 3, the reversal of poles cycle of the secondary image element of maximum brightness is configuration as small as possible preferably.Certainly, much less, the secondary image element of maximum brightness not only, whole secondary image elements with better with the plain same returing cycle configuration of the secondary image of maximum brightness.

Below, the limit with reference to Figure 21 (a) and (b), even the limit is by making reversal of poles period ratio littler, explanation more difficult embodiment that above-mentioned band shakiness takes place that observes when mobile sight line is observed embodiment illustrated in fig. 17.

In embodiment illustrated in fig. 17, constitute mark "+", "-" configuration of the high secondary image element (the secondary image element of remarks mark " H ") of brightness in the secondary image element of pixel, on column direction with (+, one), (+,-), (+,-), (+,-) counter-rotating, on line direction be+,+,+,+,+,+or-,-,-,-,-,-nonreversible, that is the form of line taking counter-rotating.To this, the mark of the secondary image element of remarks mark " H " in embodiment illustrated in fig. 21+,-configuration not only on the column direction with (+,-), (+,-), (+,-), (+,-) counter-rotating, on line direction also with (+,-), (+,-) counter-rotating, that is, embodiment illustrated in fig. 21 littler than the reversal of poles embodiment illustrated in fig. 17 cycle.In this, embodiment shown in Figure 21 is better than embodiment illustrated in fig. 17.

In addition, the configuration that constitutes the high secondary image element of the brightness of remarks mark " H " in the secondary image element of pixel among the embodiment of Figure 21 also becomes the alternate chequer shape of height, satisfies the 4th condition.

Pixel shown in Figure 21 (a) is arranged, and for example can followingly realize.

As Figure 21 (b) representation of concept, the auxiliary capacitor opposite electrode (not shown) of the secondary image element of each row constitutes like this, makes per two to be listed as one that alternately connects among auxiliary capacitor distribution CS-A or the CS-B.This structural change is by relatively Figure 21 of present embodiment and Figure 17 or Figure 18 of previously described embodiment can clearly confirm.Specifically, can on line direction, see the choice situation of the auxiliary capacitance line of secondary image primitive unit cell correspondence.For example, about the secondary image element from Spa (1,1) to Spa (1,6) row, see the words of choice situation with the auxiliary capacitance line of the auxiliary capacitor opposite electrode of mark " A " or " B " expression, among Figure 21 of present embodiment be " A " at Spa (1,1), at Spa (1,2) and Spa (1,3) be " B ", at Spa (1,4) and Spa (1,5) be " A ", be " B " alternate selection at Spa (1,6), in contrast, and all plain selections of secondary image " A " from Spa (1,1) to Spa (1,6) among Figure 17 of previously described embodiment or Figure 18.

Comprising the voltage waveform of supplying with on each distribution of the auxiliary capacitor distribution CS-A of embodiment shown in Figure 21 or CS-B can use from the voltage waveform of Figure 18 (a) to (j) expression.But, in the present embodiment, because the per 2 row reversal of poles of shows signal voltage, so the shows signal voltage of Figure 18 (a) expression is supplied with S-C1, S-C2, S-C5, the S-C6 of Figure 21 (a) ..., S-C3, S-C4, S-C7 (not shown), the S-C8 (not shown) of shows signal voltage supply Figure 21 (a) of Figure 20 (b) expression ...

In the above-described embodiments, with the opposed voltage of auxiliary capacitor of supplying with the auxiliary capacitor distribution as oscillating voltage, further, the applied load ratio is 1: 1 a square wave, but be not limited thereto, duty ratio is the square wave beyond 1: 1, even the oscillating voltage of sinusoidal wave and triangular wave etc. also can.After making the TFT that connects a plurality of secondary image elements become off-state, supply with the change in voltage of each auxiliary capacitor opposite electrode of a plurality of secondary image elements, can make this variable quantity plain different with secondary image.But, use square wave, as mentioned above, have make easily consistent and make the consistent such advantage of effective voltage of each secondary image element easily to the quantity of electric charge of each secondary image element (liquid crystal capacitance and auxiliary capacitor) charging.

In addition, in the embodiment of above-mentioned Figure 17 and Figure 21, as Figure 18 (c) (d) shown in, during the vibration period of getting the oscillating voltage of supplying with auxiliary capacitance line is 1H, but being not limited thereto, also can be natural number/one of 1H, that is (1/1) H, (1/2) H, (1/3) H, (1/4) H ...But, shorten the making of the driving circuit difficulty that becomes, the problem that the electric power that perhaps has driving circuit to consume increases with the vibration period of oscillating voltage.

As mentioned above, according to a first aspect of the invention, can improve the field angle dependence of γ characteristic of the liquid crystal indicator of normal black formula.Especially, have the γ characteristic of liquid crystal indicator of the Wide-angle characteristic of MVA mode or ASV mode etc. by improvement, can realize the demonstration that display quality is high.

In addition, according to a second aspect of the invention, glimmer in the time of can being suppressed at the AC driving liquid crystal indicator.By with the combination of according to a first aspect of the invention liquid crystal indicator, when improving the field angle characteristic of γ characteristic, providing and suppressing that flicker takes place, the liquid crystal indicator of normal black formula that can high-quality display.

Claims (6)

1. a liquid crystal indicator is characterized in that,

Possess a plurality of liquid crystal layer is respectively arranged and on described liquid crystal layer the pixel of a plurality of electrodes of extra electric field,

Described a plurality of pixel become to have multirow (1～rp) and multiple row (1～cq) matrix shape (rp cq) arranges, each pixel with P (p q) represents, wherein, 1≤p≤rp, 1≤q≤cq,

Each of described a plurality of pixels have at least two secondary image elements arranging at column direction (SPa (and p, q), SPb (p, q) ...),

Described at least two secondary image elements present different brightness mutually at a certain middle gray grade show state, and, the arrangement position of described column direction that presents the secondary image element of maximum brightness at least in described two secondary image elements, in the pixel of going arbitrarily, on line direction, change, and in the pixel that is listed as arbitrarily, be certain with specified period; Described at least two secondary image elements that each of wherein said a plurality of pixels has are configured to secondary image element that under a certain middle gray grade show state brightness equates in proper order adjacency not mutually, and described at least two secondary image elements that each of described a plurality of pixels has are in a certain middle gray grade show state, and the secondary image element with maximum brightness disposes like that to form the alternate chequer of height.

2. liquid crystal indicator according to claim 1, it is characterized in that, described a plurality of pixels each the brightness size sequence of described at least two secondary image elements and the corresponding relation of the arrangement position of the column direction of described at least two secondary image elements, changing with specified period on line direction in the pixel of going arbitrarily, is certain in the pixel that is listed as arbitrarily.

3. liquid crystal indicator according to claim 1 is characterized in that,

Described at least two secondary image elements be SPa (p, q) and SPb (p, q), in a certain middle gray grade show state,

Pixel P (the p of any row, q) the secondary image element that presents maximum brightness in, at q is to be SPa (p in the pixel of odd number, q), and in q is the pixel of even number be SPb (p, q), be to be SPb (p in the pixel of odd number perhaps at q, q) and at q is to be SPa (p, q) in any one in the pixel of even number

Arbitrarily the pixel P of row (p presents the secondary image element of maximum brightness in q), with p be that odd number or even number are irrelevant, be SPa (p, q) and SPb (p, q) in any one.

4. liquid crystal indicator according to claim 1 is characterized in that,

The direction of the described electric field that adds on the described liquid crystal layer of described a plurality of pixels was reversed in each vertical-scan period,

Under a certain middle gray grade show state, the direction of described electric field in the pixel of any row on line direction with the specified period counter-rotating, and, in the pixel of row arbitrarily on column direction every pixel inversion.

5. liquid crystal indicator according to claim 4 is characterized in that, described direction of an electric field in the pixel of any row on line direction every pixel inversion.

6. liquid crystal indicator according to claim 4 is characterized in that, described direction of an electric field in the pixel of any row on line direction per two pixel inversion.

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