CN101038408A

CN101038408A - Vertical nematic mode liquid crystal display device

Info

Publication number: CN101038408A
Application number: CN 200710040205
Authority: CN
Inventors: 刘选斌; 孙荣阁; 曹文一
Original assignee: SVA Group Co Ltd
Current assignee: SVA Group Co Ltd
Priority date: 2007-04-28
Filing date: 2007-04-28
Publication date: 2007-09-19

Abstract

The invention discloses a vertical orientation liquid crystal display device, consists of the oppositely arranged first substrate and second substrate; one liquid crystal layer filled between the first substrate and the second substrate; the second substrate has formed with a plurality of pixel zones with the pixel electrodes, the first substrate has formed with the common electrode, the pixel electrode or common electrode have formed with the groove or convex; the rim surface of pixel electrode is uneven; which may effectively change the edge electric field distribution of pixel electrode, change the orientation of liquid crystal molecular at the edge of light transmission area in pixel zone, thereby improve the black strip and increase the light transmission rate.

Description

The liquid crystal indicator of vertical alignment mode

Technical field

The present invention relates to a kind of liquid crystal indicator, particularly relate to a kind of liquid crystal indicator that can improve the vertical alignment mode of black line.

Background technology

(liquid crystal display LCD) is the orientation that changes liquid crystal molecule by the voltage that changes the liquid crystal layer both sides to liquid crystal indicator, thereby the power of control transmitted light realizes that image shows.Liquid crystal indicator usually by backlight module, first substrate that is oppositely arranged and second substrate and be filled in first substrate and second substrate between liquid crystal layer constitute, viewing area on second substrate comprises a plurality of pixel regions, be provided with thin film transistor (TFT) (TFT) and pixel electrode in it, thin film transistor (TFT) serves as on-off element; Be formed with alignment film on the inboard of first substrate and second substrate, arranged outside has Polarizer.

Liquid crystal indicator display mode commonly used at present has TN (Twist Nemetic), IPS (InPlane Switching) and VA (Vertical Alignment, vertical orientated) pattern.The major defect of TN type liquid crystal indicator is that angular field of view is narrow, the liquid crystal indicator of IPS pattern has improved the shortcoming of TN, its visual angle can reach more than 170 degree, but because its pattern is planar to rotate by liquid crystal molecule to realize that picture shows that its response speed is slow.The VA mode LCD adopts the negative type liquid crystal material, and when OFF state, liquid crystal molecule is arranged perpendicular to first and second substrate, so can obtain black preferably attitude, realizes higher contrast ratio.Orientation deflection after adding, voltage takes place in order to trigger liquid crystal molecule, as depicted in figs. 1 and 2, liquid crystal indicator first substrate 10 of VA pattern or second substrate 20 are provided with projection 13 or groove 24, the inboard of first substrate 10 and second substrate 20 is provided with

alignment film

17 and 27, its effect is liquid crystal molecule 31 to be presented perpendicular to the direction on

substrate

10 and 20 surfaces arrange under not alive situation, and liquid crystal molecule 31 did not have birefringence effect and showed black attitude this moment.And add after the voltage that when the both sides of liquid crystal layer 30 as shown in Figure 2, the orientation of liquid crystal molecule 31 deflects, just can control the size of the orientation deflection of liquid crystal molecule 31 by the voltage of control liquid crystal layer 30 both sides, thereby realize modulation the power of transmitted light.

But liquid crystal indicator to the VA pattern, polytype black line appears in edge at pixel region easily, as shown in Figure 3, Figure 4, and the appearance of black line 40, black line 41 and black line 42, can cause the transmitance of liquid crystal indicator light to descend, influence the display effect of liquid crystal indicator.Wherein, black line 40 is referred to as in the literature to the black line (disclination) of shift, it mainly is because the fringe field of pixel electrode 26 differs bigger to the force direction of the force direction of liquid crystal molecule 31 and

projection

13 or 24 pairs of liquid crystal molecules 31 of groove, thereby makes liquid crystal molecule 31 arrangement disorders and form.

And black line 41 and black line 42 belong to the black line of another type, its generation mechanism is the effect that is subjected to the fringe field of pixel electrode 26 at the liquid crystal molecule 31 at pixel edges place, and its orientation is consistent with the Polarizer 28 of second substrate, 20 sides or first substrate, 10 sides or 18 the direction of principal axis that sees through.And to the LCD of VA pattern, as shown in Figure 5, X-axis is the axle that sees through of Polarizer 18, and Y-axis is the axle that sees through of Polarizer 28, and following transmitance formula is arranged:

I_{T} = I_{0} \sin^{2} 2 α \times \sin^{2} (\frac{δ}{2})

I wherein _TThe expression transmitted light intensity, I ₀Expression incident intensity, α are the angle that liquid crystal molecule 31 orientation projections and Polarizer see through axle, and δ is the whole liquid crystal cell bit phase delay of (comprising liquid crystal layer and Polarizer).By above-mentioned formula as can be seen, when being consistent through direction of principal axis of the Polarizer 28 of the projection of liquid crystal molecule 31 orientation in somewhere and second substrate, 20 sides or first substrate, 10 sides or 18, this place just shows as black attitude.

For black line 40 such black lines, U.S. Pat 6724452 proposes to increase auxiliary projection structure 14 on first substrate 10 and is eliminated, as Fig. 6, shown in Figure 7.In Fig. 6, Fig. 7, original protruding 13 fuse on the auxiliary projection structure 14 and first substrate 10, and auxiliary projection structure 14 is parallel with the direction at pixel electrode edge 261.Like this, auxiliary projection structure 14 just can be restrained the effect of the fringe field of pixel electrode 26 effectively, makes black line 40 disappear, and the black line of black line 42 such types only occurs.

But for the such one type black line of black line 41 and black line 42, auxiliary projection structure 14 is powerless, up to the present also the reasonable way of neither one and can be eliminated fully.General solution is the width that increases BM (black matrix) on first substrate 10, the zone that

black line

41,42 occurs is blocked, but this structure can reduce the aperture opening ratio of liquid crystal indicator.

Summary of the invention

The technical matters that the present invention solves is to provide a kind of liquid crystal indicator that can improve black line, increase the vertical alignment mode of light transmission rate.

For reaching above-mentioned purpose, the invention provides a kind of liquid crystal indicator of vertical alignment mode, comprise first substrate and second substrate that are oppositely arranged; One liquid crystal layer is filled between first substrate and second substrate; Be formed with a plurality of pixel regions on described second substrate, be formed with common electrode on described first substrate, be formed with groove or projection on described pixel electrode or the common electrode with pixel electrode; The edge surface of wherein said pixel electrode is roughness.

The edge surface of described pixel electrode can be wavy or zigzag.

Based on above-mentioned design, the liquid crystal indicator of vertical alignment mode of the present invention is because the edge surface of pixel electrode is roughness, the fringe field that can change pixel electrode effectively distributes, the liquid crystal molecular orientation at pixel region photic zone edge is changed, thereby reach the purpose of improving black line and increasing light transmission rate, and the present invention need not to increase the width of BM on first substrate, can not influence aperture opening ratio.And, need not to increase any processing step according to the pixel electrode of structure of the present invention, and only need to revise the figure of pixel electrode mask plate, can not increase the production cost of pixel electrode.

In order further to understand feature of the present invention and technology contents, see also following about detailed description of the present invention and accompanying drawing.Yet accompanying drawing is only for reference and aid illustration usefulness, is not construed as limiting the invention.

Description of drawings

Fig. 1 Liquid Crystal Molecules Alignment synoptic diagram that is the VA mode LCD when making alive not;

Fig. 2 is VA mode LCD Liquid Crystal Molecules Alignment synoptic diagram when adding voltage;

Fig. 3 is the black line synoptic diagram that the pixel region part edge zone of VA mode LCD occurs;

Fig. 4 is the black line synoptic diagram that the pixel region other parts fringe region of VA mode LCD occurs;

Fig. 5 is the synoptic diagram that concerns that liquid crystal molecular orientation and Polarizer see through axle in the VA mode LCD;

Fig. 6 is that the pixel region part edge zone of VA mode LCD adds the black line synoptic diagram that occurs after the auxiliary projection structure;

Fig. 7 is the pixel region structural representation of traditional VA mode LCD;

Fig. 8 is the structural representation of the pixel electrode of traditional VA mode LCD;

Fig. 9～Figure 11 is the structural representation of the pixel electrode in the embodiment of the invention.

Among the figure:

10. first substrate, 13. protruding 14. auxiliary projection structures

17,27. alignment films, 18,28. Polarizers

20. second substrate, 24. grooves, 26. pixel electrodes

261. the edge of pixel electrode

30. liquid crystal layer 31. liquid crystal molecules

40,41,42. black lines

Embodiment

The invention will be further described below in conjunction with accompanying drawing and exemplary embodiments.

Fig. 1 Liquid Crystal Molecules Alignment synoptic diagram that is the VA mode LCD when making alive not; Fig. 2 is VA mode LCD Liquid Crystal Molecules Alignment synoptic diagram when adding voltage; Fig. 9-Figure 11 is the structural representation of the pixel electrode in the embodiment of the invention.

With reference to Fig. 1, Fig. 2 and Fig. 9, the liquid crystal indicator of vertical alignment mode, comprise first substrate 10, second substrate 20 that is oppositely arranged and be filled in first substrate 10 and second substrate 20 between liquid crystal layer 30, be formed with a plurality of pixel electrodes 26 on second substrate 20, be formed with the common electrode layer on first substrate 10, be formed with projection 13 or groove 24 on pixel electrode 26 or the common electrode, the edge surface of pixel electrode 26 is roughness.

Liquid crystal layer 30 is made of for negative and anisotropic liquid crystal material specific inductive capacity, and pixel electrode 26 and common electrode all adopt transparent conductive material to make, as ITO (tin indium oxide), IZO (zinc-tin oxide) etc.; In addition, the liquid crystal indicator of vertical alignment mode also comprises the VA

type alignment film

17,27 that is arranged on first,

second substrate

10 and 20 inboards, is arranged on the Polarizer 18,28 in the

substrate

10 and 20 outsides etc.

On second substrate 20, many gate lines that are arranged in parallel signal wire parallel with many is vertical mutually, be provided with dielectric film between described gate line and the signal wire, each overlapping place between gate line and signal wire is provided with a thin film transistor (TFT) (TFT), the TFT device serves as on-off element, per two adjacent sweep traces and signal wire define pixel region (all not showing among the figure), are provided with pixel electrode 26 in the pixel region.

With reference to Fig. 1, under making alive state not, thin film transistor (TFT) is the OFF state, because

alignment film

17 and 27, the restriction of projection 13 and groove 24, thereby the liquid crystal molecule 31 of the gap area between projection 13 and groove 24 is approximately perpendicular to first,

second substrate

10 and 20, the orientation that is positioned near the liquid crystal molecule 31 protruding 13 is approximately perpendicular to the inclined-plane of projection 13, because light is during along the transmission of the molecular axis direction of liquid crystal molecule 31, can not produce birefringence, again because of the Polarizer 17 that is separately positioned on first substrate 10 and

second substrate

20,27 polarizing axis is vertical mutually, therefore, the liquid crystal indicator of the vertical alignment mode under this state is in dark attitude.

With reference to Fig. 2, under the making alive state, thin film transistor (TFT) is the ON state, on liquid crystal layer 30, apply electric field perpendicular to first substrate 10 and second substrate 20, because liquid crystal molecule 31 is negative permittivity and anisotropic liquid crystal material, under electric field action, this liquid crystal molecule 31 will be to the direction deflection vertical with direction of an electric field, add the restriction of projection 13, make all liquid crystal molecules 31 between this first substrate 10 and second substrate 20 orientation along and

substrate

10,20 directions that tilt are arranged, at this moment, there is certain angle in the molecular axis direction of the incident direction of light and liquid crystal molecule 31, therefore this polarization of incident light attitude will change, and Polarizer 17 outgoing of part luminous energy from being arranged on this first substrate 10 will be arranged, and promptly the liquid crystal indicator of the vertical alignment mode under this state is in bright attitude.

With reference to Fig. 6 and Fig. 7, also be provided with auxiliary projection structure 14 on the common electrode of first substrate 10, projection 13 on the auxiliary projection structure 14 and first substrate 10 fuses, and it is parallel with the edge 261 of pixel electrode 26, can effectively restrain the effect of the fringe field of pixel electrode 26, make to disappear to the black line 40 of shift.

With reference to Fig. 9～11, edge 261 faces of pixel electrode 26 are roughness, the edge 261 of pixel electrode 26 can indentation or wavy, zigzag is formed by connecting by several near linears, wavyly be formed by connecting by several curve of approximation, also can be formed by connecting by zigzag and wavy mixing, zigzag or wavy can continuous distribution on the edge 261 of pixel electrode 26 also can be discontinuously arranged, as shown in Figure 8, edge 261 corresponding to the pixel electrode 26 of the position of auxiliary projection structure 14 is wavy or zigzag, and other positions can be linearly.

The liquid crystal indicator of the vertical alignment mode that the above embodiment of the present invention is given, need not to increase under the situation of BM width on first substrate 10, the fringe field that changes pixel electrode 26 by edge 261 shapes of revising pixel electrode 26 distributes, liquid crystal molecule 31 orientations of pixel edges are changed, thereby can improve

black line

41 and 42 effectively, increase the transmitance of liquid crystal indicator light.According to pixel electrode 26 shapes of the present invention, also need not to increase any processing step simultaneously, the figure that only needs to revise pixel electrode 26 mask plates gets final product, and can not increase the production cost of pixel electrode 26.

Claims

1. the liquid crystal indicator of a vertical alignment mode comprises

First substrate that is oppositely arranged and second substrate;

One liquid crystal layer is filled between first substrate and second substrate;

Be formed with a plurality of pixel regions on described second substrate, be formed with common electrode on first substrate, be formed with groove or projection on described pixel electrode or the common electrode with pixel electrode;

The edge surface of wherein said pixel electrode is roughness.

2. liquid crystal indicator according to claim 1 is characterized in that the edge surface of described pixel electrode is wavy or zigzag.

3. liquid crystal indicator according to claim 1 is characterized in that the pairing common electrode in edge of described pixel region photic zone is provided with the auxiliary projection structure that fuses with projection.

4. liquid crystal indicator according to claim 2 is characterized in that described wave or zigzag are discontinuously arranged on the edge of pixel electrode.

5. liquid crystal indicator according to claim 4, the edge that it is characterized in that described pixel electrode is wave or jagged position is corresponding with the position of described auxiliary projection structure.

6. according to claim 1,2,3,4 or 5 described liquid crystal indicators, the material that it is characterized in that described pixel electrode, common electrode is an indium tin oxide.