CN100470329C - Liquid crystal display device - Google Patents

Abstract

The invention discloses a liquid crystal display device comprising a TFT array panel on which both pixel electrodes and common electrodes are formed and a color filter panel is disposed opposing the array panel, and liquid crystals are interposed therebetween. The liquid crystals are aligned parallel to the two panels and driven by parallel electric field formed between the pixel electrodes and reference electrodes. An LCD according to the present invention includes an upper panel and a lower panel, a liquid crystal layer interposed between the upper and lower panels, wherein the liquid crystal in the liquid crystal layer is oriented in a direction declining with 2-5 DEG from the long axis which is perpendicular to the gate line; an upper and lower polarization assemblies disposed on the outer surfaces of the panels; and supporting films disposed on the upper and lower surfaces of each polarization film, wherein two supporting films facing said panels has Ro of from 0 to about 5 nm and Rth of from o to about 50 nm.

Description

Liquid crystal indicator

The application is to be the dividing an application of No. 200310119811.5 application for a patent for invention on November 6th, 2003 applying date.

Technical field

The present invention relates to Liquid crystal disply device and its preparation method, particularly about liquid crystal indicator.

Background technology

Liquid crystal indicator (" LCD ") comprises upper and lower two panels that have a living electrode and inserts liquid crystal layer between them.Apply voltage on the living electrode on the scene and can in liquid crystal layer, produce electric field.Can control the transmitance of the light that passes liquid crystal layer by the intensity of regulating electric field, show required image thus.

The LCD of usage level electric field comprises as a public electrode and an a plurality of pixel capacitors of giving birth to electrode, and they are formed on the panel that has a plurality of thin film transistor (TFT)s (" TFT ").Produce the electric field that is parallel to panel by public electrode and pixel capacitors, be used for liquid crystal molecule is rearranged the transmitance of passing the light of panel with control.In addition, film partially is set together usually on the outside surface of TFT substrate and colored filter substrate.

TFT type LCD has various advantages, for example low-power consumption, low driving voltage, in light weight and thin thickness etc.The TFT transistor array board can comprise thin film transistor (TFT), pixel capacitors, gate line and data line usually.On the other hand, colored filter board generally includes colored filter and public electrode.Be provided for starting the gate drive signal of thin film transistor (TFT) to the gate electrode of film transistor array plate through gate line by gate drivers.Offer pixel capacitors by data driver through the data-signal that data line will be added in the thin film transistor (TFT) source electrode, be used for the LCD pixel of switchable liquid crystal layer.

A measurement index of LCD performance is the visual angle, and has dropped into a large amount of effort for the wide visual angle of exploitation by various wide field-of-view modes.In a kind of field-of-view mode, used the face internal conversion (In-PlaneSwitching, IPS).In this pattern, the installation that is parallel to each other of two electrodes in each unit, and liquid crystal molecule is more freely rotated to carry out the oneself arrange, improve the visual angle thus in electric field.Recently, adopt two farmlands IPS pattern of class zigzag electrode allocation scheme, can further improve the distribution of electric field, and make LCD can show identical color from the left and right sides.Two farmlands IPS patterns has overcome the blue drift of a side that color distortion causes and the yellow of opposite side is drifted about.But, because the visual angle can not equal 80 ° or bigger, thus do not realize real wide visual angle, and also if serious yellow drift is difficult to demonstrate grey under black state.In other words, the horizontal field pattern LCD that shows black image observes and yellow drift can occur from-side.This be attributed to from unilateral observation to green and the seepage of red light, this can make display performance for example sharpness or contrast deterioration.And because yellow drift, the visual angle narrows down, and color performance neither optimum.

Need below existing for LCD thus: the yellow of using parallel electric field to reduce under the black state is drifted about, and improves the contrast of all directions, increases the visual angle and improves colouristic properties.

Summary of the invention

According to one embodiment of present invention, provide a kind of liquid crystal indicator, comprising: relative upper and lower panel; The liquid crystal layer of clamping between upper and lower panel; Be configured in lip-deep upper and lower the inclined to one side assembly of upper and lower panels outside; And be clipped in top panel and gone up between the inclined to one side assembly or be clipped in lower panel and following inclined to one side assembly between phase shift films, wherein this phase shift films is accurate A-plate compensate film (quasi A-plate compensationfilm).

Preferably, the range of delay values of phase shift films arrives between about 100nm at about 20nm.And this accurate A-plate compensate film has nx-ny〉refraction ansiotropy of ny-nz, nx, ny and nz are respectively the refractive indexes along x, y, z axle here.Upper and lower panel comprises a colored filter board and a tft array plate.Play inclined to one side assembly and comprise two support membranes, wherein each support membrane comprise Triafol T (triacetatecellulose, TAC).

According to a further aspect in the invention, electrode is set to be operated in and switches in the face of two farmlands under (IPS) pattern to produce horizontal component of electric field.According to a further aspect of the invention, play inclined to one side assembly and comprise the light circulation film of DBEF-D film, Bepol or Nipocs for example.

According to another embodiment of the invention, provide a kind of liquid crystal indicator, comprising: relative upper and lower panel; Be clamped in the liquid crystal layer between the upper and lower panel; Be configured in lip-deep upper and lower the inclined to one side assembly of panels outside; And be arranged on the upper and lower lip-deep support membrane that each plays inclined to one side film, wherein two support membranes towards panel comprise the Ro of 0nm and 0 to about 50nm Rth.

According to this embodiment on the other hand, the liquid crystal in the liquid crystal layer be arranged as basically leave major axis tilt about 2 to about 5 the degree, this major axis and gate line quadrature.Surely A-plate compensate film is clipped between top panel and last inclined to one side assembly or lower panel and following the inclined to one side assembly.

According to an embodiment more of the present invention, a kind of liquid crystal indicator is provided, comprising: relative upper and lower panel; Be clamped in the liquid crystal layer between the panel; Be arranged on the pre-tilt liquid crystal in the liquid crystal layer; And be configured in lip-deep a pair of the inclined to one side assembly of panels outside.

Thus, the invention provides the liquid crystal indicator that has the improvement contrast and reduced yellow drift.This realizes by following manner: insert a phase shift films between a panel and an inclined to one side assembly, the support membrane that the Ro and 0 with 0nm arrives the Rth of about 50nm perhaps is set on an inclined to one side film.Also can obtain by in panel, forming first and second oriented films that have a pre-angle of deviation.

Description of drawings

By research below in conjunction with the accompanying drawing detailed description of the preferred embodiment, can be better and understand above-mentioned and other characteristics of the present invention more fully.

Fig. 1 is the sectional view of LCD according to an embodiment of the invention;

Fig. 2 A is the layout that is used for the tft array plate of LCD according to an embodiment of the invention;

Fig. 2 B and 2C are that tft array plate shown in Fig. 2 A is respectively along II B-II B ' and II C-II C ' and IIC '-II CC " sectional view;

Fig. 3 A and 3B arrange and the synoptic diagram of the frictional direction of LCD according to the slow axis of the compensate film of the first embodiment of the present invention (slow axis);

Fig. 4 A and 4B are the detection figure that makes by optical detection apparatus, and it has shown is not having under the accurate A-plate compensate film situation and yellow difference of drifting about under the situation that accurate A-plate compensate film is provided according to the embodiment of the invention;

Fig. 5 A and 5B be respectively do not have and have LCD under the accurate A-plate compensate film situation etc. correlation curve (isocontrast curve) figure;

Fig. 6 A and 6B represent that respectively the observation place is respectively the color coordinate figure that (60 degree, 40 degree) and (60 degree, 60 degree) are located at polar angle (polar angle) and position angle (azimuthalangle);

Fig. 7 is a LCD sectional view according to another embodiment of the present invention;

Fig. 8 is the color coordinate figure of LCD in the CIE coordinate system that has various inclined to one side films and show black image;

Fig. 9 is the LCD sectional view according to an embodiment more of the present invention.

Embodiment

Below with reference to the accompanying drawing of preferred illustrated embodiment, the present invention is more fully described.But the present invention can also implement in a different manner, is not subjected to the restriction of the embodiment that mentions here.

In the drawings, the thickness and the scope of having amplified each layer in order to know.Middle in the whole text same reference numerals is corresponding to same parts.When mention parts such as layer, film, zone, substrate or panel another parts " above " time, can be understood as directly and on another parts or also, may have intermediate member.Opposite, when pointing out that parts " directly exist " on another parts, just there is not intermediate member.

To be introduced LCD according to an embodiment of the invention with reference to accompanying drawing.

Fig. 1 is a LCD sectional view according to an embodiment of the invention, Fig. 2 A is the layout that is used for the tft array plate of LCD according to one embodiment of the invention, Fig. 2 B and 2C be comprise tft array plate shown in Fig. 2 A LCD respectively along II B-II B ' and II C-II C ' and II C '-II CC " sectional view.Fig. 3 A and 3B arrange and the synoptic diagram of LCD frictional direction according to the slow axis of the compensate film of the first embodiment of the present invention (slow axis).

LCD comprises that a tft array plate 1, a colored filter board 2, relative with tft array plate 1 are used for sealing liquid crystal layer 3 and are arranged on the liquid crystal layer that includes a plurality of liquid crystal molecules 3 in the gap between panel 1 and 2 at the sealant 320 and that forms a gap between panel 1 and 2 according to an embodiment of the invention.LCD further comprises the inclined to one side assembly 12 of a pair of on the outside surface that is separately positioned on panel 1 and 2 and 22, and is inserted in the phase shift films 24 between a colored filter board 2 and the inclined to one side assembly 22.

With reference to Fig. 2 A to 2C, tft array plate 1 comprises many gate lines 121; many public electrode wires 130; cover the gate insulator 140 on the gate line 121; be formed on a plurality of semiconductor islands 154 on the gate insulator 140 that is positioned on the gate electrode; a plurality of ohmic contact 163 and 165; many data lines 171; the a plurality of drain electrodes 175 relative with source electrode 173; a plurality of pixel capacitors 190; one covers and protects the passivation layer 180 of semiconductor island 154; a plurality of auxiliary contacts (contact assistant) 91 and 92; and be formed on oriented layer (alignment layer) 11 on the insulated substrate 110.

Every the gate line 121 that is used to transmit signal comprises a plurality of gate electrodes, and every the data line 171 that is used to transmit data voltage comprise with drain electrode 175 about the relative a plurality of source electrodes 173 of gate electrode.A gate electrode, a source electrode 173 and a drain electrode 175 connect same semiconductor island 154 and form a TFT, and it responds signal and transmits data voltage.As shown in the figure, semiconductor island 154 is provided with near other semiconductor island.

Every public electrode wire 130 is in the layer identical with gate line 121 and be arranged between the two adjacent gate lines 121.Public electrode wire 130 is applied in a common electric voltage, and it comprises a plurality of interconnective public electrodes 131.Each public electrode 131 comprises that extend, similar pectination up and down a plurality of 132-134 of branch.

Each pixel capacitors 190 is connected on of drain electrode 175, and comprises that extend, similar pectination up and down a plurality of branches 191 and 192.The 132-134 of branch of public electrode 131 and the 191-192 of branch of pixel capacitors 190 alternately arrange and mutual substantially parallel extension, and the electric field that they produce when making the voltage that applies different amplitudes thereon is arranged essentially parallel to panel 1 and 2.

According to a preferred embodiment of the invention, pixel capacitors 190 and public electrode 131 form with class zigzag pattern, are shown in as Fig. 2 A to have bending or angle on the predetermined length.For all electrodes, such bending or angle character all are identical, are arranged essentially parallel to data line 171.Therefore, pixel capacitors 190 and public electrode 131 also are parallel to each other.If apply an electric potential difference, then form horizontal distribution and be parallel to the electric field of two plate faces 1 and 2 (Fig. 1) so that liquid crystal molecule is carried out permutatation in pixel capacitors 190 and 131 of public electrodes.

Gate line 121 and public electrode wire 130 that gate insulator 140 covers except end 129, and semiconductor island 154 is positioned on the gate insulator 140. Ohmic contact 163 and 165 is inserted in respectively between semiconductor island 154 and the data line 171 and reaches between semiconductor island 154 and the drain electrode 175, to reduce contact resistance therebetween.

Data line 171, drain electrode 175, pixel capacitors 190 and semiconductor island 154 that passivation layer 180 covers except end 179.

Auxiliary contact 91 and 92 is by being provided at the contact hole 181 and 182 on gate insulator 140 and the passivation layer 180; be connected respectively to the exposed end 129 and 179 of gate line 121 and data line 171; be used to protect the end 129 and 179 and replenish the adhesion of tft array plates 1 of exposure, and drive IC thus.

Gate line 121 and data line 171 mutual intersections have been determined a plurality of closed regions by matrix distribution.Paired pixel capacitors 190 and public electrode 131 is provided in each closed region.

Data line 171, public electrode 131 and pixel capacitors 190 are provided with in parallel to each other, and are shown in as Fig. 2 A and have angle bending on the predetermined length, preferably at about intermediate point of each closed region.

Though embodiments described herein are two farmland type IPS, those skilled in the art can easily release this embodiment can be used for conventional IPS type LCD.

Colored filter board 2 comprises a black matrix" 220 and a plurality of colored filter 230 and the oriented layer 21 that is formed on the insulated substrate 210.Black matrix" 220 has towards a plurality of openings with the closed region of arranged, and each colored filter 230 all is arranged in the opening of black matrix" 220 and as one of three mass-tones, for example red, green and blue look.According to another embodiment of the present invention, colored filter 230 can be arranged on the tft array plate 1, replaces colored filter panel 2.Do not having under the situation of added electric field, liquid crystal molecule 3 following arrangements: their main shaft be orientated be arranged essentially parallel to panel 1 and 2 and basically with gate line 121 quadratures (for example, as the direction of representing by arrow 4 in Fig. 2 A and 3), such arranges by obtaining along arrow 4 rubbing alignment layers 11 and 21.Liquid crystal molecule 3 rotations and its anglec of rotation depend on electric field intensity when applying electric field.

With reference to Fig. 1, each plays two lip-deep two support membrane 12a and 12c or 22a and 22c that inclined to one side assembly 12 or 22 comprises together film 12b or 22b partially, invested inclined to one side film 12b or 22b.Each plays inclined to one side assembly 12 or 22 and may further include a light circulation film (not shown) that combines with an inclined to one side film 12b or 22b.Light circulation film (light recycling film) preferably includes commercial DBEF-D film, Bepol or Nipocs.

Play the absorption axes (or seeing through axle) that inclined to one side film 12b and 22b have intersection, and the main shaft of the absorption axes that one of rises among inclined to one side film 12b and the 22b when being parallel to liquid crystal molecule 3 (or liquid crystal director) initial arrangement.

Support membrane 12a, 12c, 22a and 22c preferably include Triafol T (triacetate cellulose, TAC) film.

According to embodiments of the invention, between a colored filter board 2 and an inclined to one side assembly 22, a phase shift films 24 is set.This phase shift films preferably includes A-plate uniaxial compensation film surely, and it has the refractive index anisotropy, makes nx-ny〉ny-nz, wherein nx, ny and nz are respectively the refractive indexes along x, y and z axle, this moment, the z axle was defined as the surface perpendicular to film.One conventional A-plate compensate film have be expressed as nx the refractive index of ny or nz and ny=nz.Accurate A-plate compensate film is preferred, because it has reduced the yellow drifting problem of side under black state by the birefringence effect on the compensation display.

With reference to Fig. 3 A and 3B, accurate A plate compensate film 24 is provided with as follows: its slow axis n _‖(be the x axle, refractive index is along x axle maximum) is parallel to the inceptive direction of liquid crystal director, here

Be and slow axis n _‖The axle of quadrature (for example y axle).Fig. 3 A and 3B show that liquid crystal molecule 3 from its inceptive direction rotation has taken place owing to electrode 190 and 131 electric fields that produce.The delay that is defined as the compensate film 24 of ((nx-xy) * (thickness)) has the value in about 100nm scope at about 20nm.

According to another embodiment of the invention, phase shift films 24 is inserted between a tft array plate 1 and the inclined to one side assembly 12.

Fig. 4 A and 4B are that (conoscope: the detection figure that name of product) makes, it has shown is not having under the A plate compensate film situation and the difference of yellow drift under according to the situation that the invention provides accurate A-plate compensate film by optical detection apparatus.

Shown in Fig. 4 A, when not using accurate A-plate compensate film, when from top diagonal observation LCD panel, there is serious yellow drift.But as Fig. 4 B as can be seen, accurate A-plate compensate film wherein used according to the invention can be seen the good black that does not have yellow drift.

Fig. 5 A and 5B be respectively do not have and have LCD under the accurate A-plate compensate film situation etc. correlation curve figure.Z-axis is represented the polar angle that the vertical axes on the lcd screen records, and transverse axis is represented the position angle that records from the axle of normal to screen.A plurality of concentric circless are by 20 degree arranged spaced.Wait correlation curve during 10: 1 contrast of Reference numeral 5 expression, the shadow region represents that contrast was less than 10: 1 zone.

Shown in Fig. 5 A, when not having compensate film, when surpassing 60 degree at upper left side and visual angle, upper right side when, the contrast of LCD drops to below 10: 1.But shown in Fig. 5 B, the LCD that has a compensate film keeps the good contrast greater than 10: 1 on all directions.

Fig. 6 A and 6B represent that respectively the observation place is respectively the color coordinate figure of (60 degree, 40 degree) and (60 degree, 60 degree) at polar angle and position angle.The red color coordinate is provided by x, and green chromaticity coordinate is provided by y.Usually, the upper right side part of figure is represented yellow drift and the lower left part of figure is represented blue drift.In Fig. 6 A and 6B, there is not the coordinate of the LCD of accurate A-plate compensate film to represent by mark POL, be that the coordinate of LCD of the accurate A-plate compensate film of 40nm, 50nm, 59nm and 107nm is represented by reference number A4, A5, A8 and A16 respectively and have length of delay.

Shown in Fig. 6 A and 6B, for the LCD that does not have accurate A-plate compensate film, even color coordinate POL still shows yellow drift under black state.For the LCD that has accurate A-plate compensate film, color coordinate A4, A5, A8 and A16 be to blue drift motion, for example along with the length of delay of accurate A-plate compensate film is increasing, and its color coordinate more close blueness that becomes.Yet, if length of delay too conference make color coordinate become blueness, so will carefully select the length of delay of accurate A-plate compensate film.Become obviously if when length of delay surpasses about 100nm, find blue drift, and exist yellow to a certain degree to drift about during less than about 20nm when length of delay.Therefore, the length of delay of accurate A-plate compensate film preferably arrives in the scope of about 100nm at about 20nm.

Now, the Fig. 7 in reference to the accompanying drawings is introduced according to another embodiment of the present invention liquid crystal indicator.

Fig. 7 is a LCD sectional view according to another embodiment of the present invention.As shown in Figure 7, LCD according to this embodiment of the invention comprises: a tft array plate 1, a colored filter board 2 towards tft array plate 1, be used for sealing liquid crystal layer 3 and at sealant 320 that forms a gap between panel 1 and 2 and the liquid crystal layer that includes liquid crystal molecule 3 that is arranged on gap between panel 1 and 2.LCD further comprises the inclined to one side assembly 12 of a pair of on the outside surface that is separately positioned on panel 1 and 2 and 22.

Tft array plate 1 and colored filter board 2 preferably have as Fig. 2 A to the structure shown in the 2C.

According to present embodiment, each plays two lip-deep two support membrane 12a and 12c or 22a and the 22c that inclined to one side assembly 12 or 22 comprises inclined to one side together film 12b or 22b, invested inclined to one side film 12b or 22b.Film 12a-12c and 22a-22c provide phase delay to be inverted problem to enlarge the visual angle or to solve gray scale.

Indicate horizontal delay (Rh or the Ro) value of the phase delay degree of these films on the direction that is parallel to the film surface to be expressed as follows:

Rh＝(Nx-Ny)×d (1)

Or

Ro＝(Nx-Ny)×d (1)′

Wherein d is the thickness of film, and Nx and Ny are being parallel on the direction of gate line and perpendicular to the refractive index on the direction of gate line.

With film Surface Vertical direction on the vertical delay (Rv) of film provide by following formula:

$\mathrm{Rv}=(\frac{\mathrm{Nx}+\mathrm{Ny}}{2}-\mathrm{Nz})\×d---\left(2\right)$

Wherein Nz is perpendicular to the refractive index on the direction on film surface.In theory, support membrane 12a, 12c, 22a and 22c have certain vertical delay (Rv) and do not have horizontal delay (Rh).But owing to be difficult to produce first to fourth support membrane that Rh is zero (0), first to fourth support membrane of producing preferably has the Rh of 0nm to about 5nm.Like this, obviously, support membrane 12c and 22a help to improve the display performance of LCD.

Phase delay on the thickness direction (Rth) is provided by following formula:

$\mathrm{Rth}=(\frac{\mathrm{Nx}+\mathrm{Ny}}{2}-\mathrm{Nz})\×d---\left(2\right)\′$

Wherein Rth is illustrated in the phase delay on the thickness direction of film, and Nz is a film forming molecule refractive index in vertical direction.Usually, the Rth of film has the compensating delay feature from the light of inclination liquid crystal.Yet in horizontal component of electric field LCD, liquid crystal does not tilt.Therefore, the Rth of film causes back setting effect.That is, liquid crystal can not cause the delay of light but film causes the delay of light.This causes the seepage of light.

When the delay that causes by film during greater than the delay that causes by liquid crystal, yellow drift appears under black state.Therefore, (22a, Rth 22c) minimizes, and can reduce the yellow drift under black state by making the second and the 3rd support membrane.

(Triethylgallium TEG) plays inclined to one side film to the triethyl-gallium of use Chang Zuowei notebook computer film, drifts about from the yellow that a side can be observed under black state.Between the second and the 3rd support membrane and LCD two panels, additionally be provided with under the situation of TAC film, also can observe the yellow drift under the black state from a side.Selective epitaxial growth (Selective Epitaxial Growth, SEG) rise inclined to one side film be have 50-60nm Rth used inclined to one side film always, TEG plays inclined to one side film and then has less Rth.

In Fig. 8, the regional A of CIE coordinate system has shown when playing the drift of the yellow under black state when additionally TAC being set on the inclined to one side film at SEG, and area B has shown the drift of the yellow under black state when only using SEG to play inclined to one side film.Zone C has shown the drift of the yellow under black state when only using TEG to play inclined to one side film.

As shown in Figure 8, when playing when having more TAC on the inclined to one side film yellow drift at SEG significantly, and yellow the drift reduces when using the little TEG of Rth to play inclined to one side film.

Therefore, have when playing the littler film of the Rth of inclined to one side film than TEG if use, the yellow under the black state of Guan Chaing is drifted about and will be greatly improved from the side.

According to one embodiment of the invention, the Ro of the second and the 3rd support membrane and Rth preferably are respectively 0nm and 0 to about 50nm.

Fig. 9 has shown according to the LCD of an embodiment more of the present invention.Among Fig. 9 with above-mentioned accompanying drawing in identical Reference numeral represent same parts described in above-mentioned accompanying drawing with identical function.

As shown in Figure 9, LCD comprises: a tft array plate 1 and the colored filter board 2 relative with it, be clipped in the liquid crystal layer 3 between two panels 1 and 2, be arranged on first and second the inclined to one side film 12b and the 22b in the two panels 1 and 2 outsides, and the first to fourth support membrane 12a, 12c, 22a and the 22c that are used to support first and second inclined to one side film 12b and 22b.

Can illustrate more accurately tft array plate 1 with reference to figure 2A to 2C.Shown in Fig. 2 A to 2C, many gate lines 121, data line 171, TFT, pixel capacitors 190 and public electrode wire 130 on tft array plate 1, have been formed.Gate line 121 and data line 171 intersect mutually to have determined to be arranged in a plurality of pixel regions of matrix.In each pixel area, provide TFT, pixel capacitors 190 and public electrode 131.

If between pixel capacitors 190 and public electrode 131, apply a voltage difference, then produce the electric field that is parallel to two panels 1,2 and be used to rearrange liquid crystal.

One black matrix", colored filter etc. are formed on the colored filter board 2.Black matrix" defines the pixel area of matrix pattern, forms red, green and blue color colo(u)r filter at each pixel area.The colored filter that substitutes on colored filter board 2 can formed on the tft array plate 1.

The following arrangement of liquid crystal molecule in liquid crystal layer 3: their major axis and gate line 121 (direction of arrow among Fig. 2 A) quadrature, such arrangement is to obtain by the oriented layer (not shown) that is formed on the two panels 1,2 by the direction friction of representing as the arrow among Fig. 2 A.

The inclined to one side film 12b of the first and the second inclined to one side film 22b can combine by the inclined to one side together same light circulation of the film film of general and make.The DBEF-D film, Bepol, or Nipocs can be used as light circulation film.Seeing over from the front, the absorption axes of two inclined to one side film 12b and 22b (or seeing through axle) is arranged mutually orthogonally, and the major axis of one of two absorption axes of two inclined to one side film 12b and 22b and liquid crystal be arranged in parallel.Preferably, TAC (triacetyl cellulou, Triafol T) is used for first to fourth support membrane.

Generally, the Rth of film has the function of the delay of the light that compensation causes by the inclination liquid crystal.But in parallel electric field LCD, liquid crystal does not tilt.Therefore, the Rth of film causes boomerang effect.That is, liquid crystal can not cause the delay of light but film causes the delay of light.This causes the seepage of light.

When the delay that causes by film during greater than the delay that causes by liquid crystal, at black state yellow drift appears.Therefore, be used for the conventional Rth that plays the TAC of inclined to one side film if the liquid crystal in parallel electric field LCD tilts with compensation, then the drift of the yellow under black state can improve.Generally, the pre-tilt angle of the oriented layer of horizontal component of electric field LCD be about 1 to about 2 the degree.Therefore, when from unilateral observation,, can solve the yellow drifting problem in the black state that the residue Rth by TAC causes by the oriented layer that use has big slightly pre-tilt angle.

Preferably, when supposition phase delay in the horizontal direction is Ro, Rth is a thickness direction, angle between first panel and liquid crystal major axis is the first angle θ 1, when the angle between second panel and the liquid crystal major axis is the second angle θ 2, the Ro of the second and the 3rd support membrane and Rth preferably are respectively 0nm and about 50 to about 70nm, and first and second angles are about 2 to about 5 degree.

Owing to be difficult to produce first to fourth support membrane of the Ro with zero-lag, first to fourth support membrane of producing preferably has the Ro of 0nm to about 5nm.

Preferably, first and second oriented films that are formed on first and second panels have the about 2 pre-tilt angles to about 5 degree.

As mentioned above,, provide A-plate compensate film surely, can reduce the yellow drift under black state and improve the contrast of side-looking by the LCD that gives the usage level electric field according to the present invention.Its direct advantage is to have enlarged the visual angle and improved color performance.

And,, also can reduce the yellow drift under the black state and improve the contrast of side-looking by upper and lower the inclined to one side film that provides the phase delay that makes on the thickness direction to diminish.And, can reduce yellow drift by minimizing of support membrane Rth.

Though the present invention is described in detail with reference to above preferred embodiment, but can know that the present invention is not subjected to the restriction of these disclosed embodiments, on the contrary, but wish to cover the purport that is included in appended claim and the various variations in the scope and equivalence and be provided with.

Claims (11)

1. liquid crystal indicator comprises:

Relative upper and lower panel;

Be clipped in the liquid crystal layer between the described upper and lower panel, wherein the long-axis orientation of the liquid crystal in this liquid crystal layer is that this major axis is perpendicular to gate line from last or lower panel inclination 2 to 5 degree;

Be configured in upper and lower inclined to one side assembly on the outside surface of described panel, this upper and lower inclined to one side assembly comprised inclined to one side film respectively; With

Be arranged on the upper and lower lip-deep support membrane that each plays inclined to one side film, wherein in the face of two support membranes of described panel have 0 to 5nm Ro and 0 to 50nm Rth, Ro is a phase delay in the horizontal direction, and Rth is the phase delay on thickness direction.

2. liquid crystal indicator as claimed in claim 1, one in the wherein said upper and lower panel comprises colored filter board, another comprises the tft array plate.

3. liquid crystal indicator as claimed in claim 1, wherein electrode is set to be operated in switch under (IPS) pattern in the face of two farmlands and is used to produce horizontal component of electric field.

4. liquid crystal indicator as claimed in claim 1, wherein surely A-plate compensate film be inserted in this top panel and should go up between the inclined to one side assembly or this lower panel and this following inclined to one side assembly between, wherein this accurate A-plate compensate film has nx-ny〉the anisotropic refraction rate of ny-nz, wherein nx, ny and nz are respectively the refractive indexes along x, y, z axle.

5. liquid crystal indicator comprises:

Relative upper and lower panel;

Be clipped in the liquid crystal layer between the described panel;

Be arranged on the pre-tilt liquid crystal in this liquid crystal layer, wherein the long-axis orientation of this liquid crystal is for departing from 2 to 5 degree from last or lower panel, and this major axis is perpendicular to gate line; With

Be configured in upper and lower inclined to one side assembly on the outer surface of described panel.

6. liquid crystal indicator as claimed in claim 5, one in the wherein said upper and lower panel comprises colored filter board, another comprises the tft array plate.

7. liquid crystal indicator as claimed in claim 5, wherein this upper and lower inclined to one side assembly included inclined to one side film and has been arranged on the upper and lower lip-deep support membrane that each plays inclined to one side film.

8. liquid crystal indicator as claimed in claim 7, wherein each support membrane comprises Triafol T (TAC).

9. liquid crystal indicator as claimed in claim 5, wherein this upper and lower inclined to one side assembly includes light circulation film, and this light circulation film is the material that is selected from the group that is made of DBEF-D, Bepol and Nipocs.

10. liquid crystal indicator as claimed in claim 7, wherein the Ro of this support membrane is 0nm to 5nm, Ro is a phase delay in the horizontal direction.

11. liquid crystal indicator as claimed in claim 5, wherein surely A-plate compensate film be inserted in this top panel and should go up between the inclined to one side assembly or this lower panel and this following inclined to one side assembly between, wherein this accurate A-plate compensate film has nx-ny〉the anisotropic refraction rate of ny-nz, wherein nx, ny and nz are respectively the refractive indexes along x, y, z axle.

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