JP2010169994A - Liquid crystal display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display panel, which reduces such a problem that disclination does not disappear but remains even after pressing force is released in a liquid crystal display panel of a FFS (fringe field switching) mode having slits bent in a dogleg shape. <P>SOLUTION: Slit apertures S1 and S2 are in a dogleg shape; and in each slit, directions of electric fields are reversed between positive and negative directions with respect to the direction of a rubbing process, at a joint portion J1 as a boundary, and also at both side ends, directions of electric fields are reversed between positive and negative directions with respect to the direction of the rubbing process. A wedge-like recess T1 or a projection T2 which narrows the angle of the direction of the electric field with respect to the direction of the rubbing process, is formed at the joint portion on the side of the slit aperture S1, S2, where at least three portions exhibiting reversed directions of the electric fields between positive and negative directions with respect to the direction of the rubbing process exist along the same side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an FFS (Fringe Field Switching) mode liquid crystal display panel,
The present invention relates to an FFS mode liquid crystal display panel in which a slit-like opening of an upper electrode has a “<” shape, a reverse twist domain generated when pressed from the outside easily disappears, and the transmittance is high.

Liquid crystal display panels are characterized by their light weight, thinness, and low power consumption compared to CRTs (cathode ray tubes), and are therefore used in many electronic devices for display purposes. The liquid crystal display panel displays an image by changing the direction of liquid crystal molecules aligned in a predetermined direction by an electric field by rubbing the alignment film, thereby changing the amount of light transmitted or reflected.

As a method of applying an electric field to a liquid crystal layer of a liquid crystal display panel, there are a vertical electric field type and a horizontal electric field type. A vertical electric field type liquid crystal display panel applies a substantially vertical electric field to liquid crystal molecules by a pair of electrodes arranged with a liquid crystal layer interposed therebetween. Known examples of the vertical electric field type liquid crystal display panel include a TN (Twisted Nematic) mode, a VA (Vertical Alignment) mode, and an MVA (Multi-domain Vertical Alignment) mode. A horizontal electric field type liquid crystal display panel is provided with a pair of electrodes insulated from each other on one inner surface side of a pair of substrates disposed with a liquid crystal layer interposed therebetween, and a substantially horizontal electric field is applied to liquid crystal molecules. To be applied. This horizontal electric field type liquid crystal display panel has an IP in which a pair of electrodes do not overlap in a plan view.
An S (In-Plane Switching) mode and an overlapping FFS mode are known.

Among them, in the FFS mode liquid crystal display panel, a pair of electrodes composed of an upper electrode and a lower electrode are arranged in different layers with an insulating film interposed therebetween, and a slit-like opening is provided in the upper electrode, and this slit-like opening is passed through. A substantially horizontal electric field is applied to the liquid crystal layer. The FFS mode liquid crystal display panel is widely used in recent years because it can obtain a wide viewing angle and improve image contrast.

In the FFS mode liquid crystal display panel, the slit-shaped opening extends so as to be slightly inclined with respect to the rubbing direction so that the liquid crystal molecules can rotate in the same direction.
In a liquid crystal display panel for color display, the change in color due to the viewing angle can be reduced by multi-domaining in which the inclination angle of the slit-shaped opening with respect to the rubbing direction is divided into two areas, positive and negative. However, it is difficult to form an electric field in a desired direction at the end of the slit-like opening, and when the slit-like openings having different extending directions are separated from each other, the end of the slit-like opening is increased and the aperture ratio is lowered.

Therefore, in the liquid crystal display panel disclosed in Patent Document 1 below, the slit-shaped openings are zigzag-shaped, and the slit-shaped openings extending in different directions are connected to achieve multi-domain and a large aperture ratio. It is trying to become. In addition, about the edge part of a slit-shaped opening, as disclosed in the following Patent Document 2, by reducing the part where the tangential direction of the edge part with respect to the rubbing direction is between 0 ° and −90 °. It is known that the disclination generation area can be suppressed. Further, in the liquid crystal display element disclosed in Patent Document 3 below, a slit-like opening is bent in a “<” shape, and a wedge-shaped protrusion that is bent in a direction in which the inclination angle with respect to the alignment treatment direction is further increased at the bent portion. By forming the portion and the concave portion, reverse twist is hardly generated in the bent portion.

JP 2002-014374 A JP 2008-096840 A JP 2008-083386 A

When two slit-like openings having different extending directions are formed, regions (domains) having different orientation directions of liquid crystal molecules are formed on the respective slit-like openings, so that there is an advantage that wide viewing angle characteristics can be obtained. . However, when two slit-like openings having different extending directions are connected, a portion (disclination) in which the alignment direction of the adjacent liquid crystal molecules is different is generated at this joint, but the region where the disclination occurs is normal. Cannot be displayed properly. In addition, simply connecting two slit-like openings with different extending directions in a "<" shape causes a large disclination when the surface of the liquid crystal display panel is pressed, resulting in uneven display. In some cases, disclination does not disappear and continues to remain even when the pressure is released.

As a result of various studies on the cause of the disclination, the inventors have found that the disclination does not disappear even when the pressure from the surface of the liquid crystal display panel is released. This phenomenon will be described with reference to FIGS.

FIG. 7 is a schematic view showing the rotation direction of the liquid crystal molecules in the slit-like opening of the conventional liquid crystal display panel. FIG. 8 is a schematic diagram showing a disclination generation state of a conventional liquid crystal display panel.

In the liquid crystal display panel shown in FIG. 7, the rubbing direction is the column direction, and the slit-shaped opening S4.
Is a “<” shape extending in the column direction, and includes an upper slit portion U4 and a lower slit portion D4. The upper end of the upper slit portion U4 and the lower end of the lower slit portion D4 protrude so as to taper in a banana shape in order to suppress the occurrence of disclination. The rotation direction of the liquid crystal molecules when an electric field is applied in such a “<”-shaped slit-shaped opening is such that the long edge line on the inner corner side (right side) and the outer corner side (left side) of the upper slit portion U4 is counterclockwise L ( Counterclockwise), and the long edge lines on the inner and outer corners of the lower slit portion D4 are clockwise R (clockwise).

An end E4U in which the rotation direction of the liquid crystal molecules when an electric field is applied is clockwise R exists above the edge line on the inner angle side of the upper slit portion U4, and the inner edge side edge of the lower slit portion D4 Below the line is an end E4D in which the rotation direction of the liquid crystal molecules when an electric field is applied is counterclockwise L.
Further, a small “<”-shaped slit-shaped opening S5 at the right end in FIG. 7 is an upper slit portion U5.
The edge E5U where the rotation direction of the liquid crystal molecules is clockwise R when an electric field is applied above the edge line on the outer angle side of
There is an end E5D where the rotation direction of the liquid crystal molecules when the electric field is applied is counterclockwise L below the edge line on the outer angle side of the lower slit portion D5.

In the FFS mode liquid crystal display panel, the liquid crystal is rotated clockwise R or counterclockwise L in a plane.
As the orientation changes, the transmittance increases, but at the boundary between the clockwise R portion and the counterclockwise L portion, there is a region that cannot be rotated in either direction. It becomes an area that does not. On the other hand, the transmittance is improved to some extent in the region where the portions in the same rotation direction are adjacent to each other.

Here, consider a case where the liquid crystal alignment is disturbed by applying a physical pressure or the like such as pressing the liquid crystal display panel. The stable state of the liquid crystal is a state in which the long axes are aligned in the direction along the lines of electric force, and the right-handed rotation R is in the most stable state or the left-handed L has a state close to the stable state. for that reason,
If there is a stable counterclockwise L portion adjacent to the clockwise R portion, the counterclockwise L may be stabilized even if the clockwise R is in a stable state region.

FIG. 8 shows this state. For example, the lower slit portion D4 of the slit opening S4
The right edge line is a clockwise R portion, but may be stabilized at the counterclockwise L by being pressed from the outside. In this case, the left edge line of the slit-shaped opening S5 adjacent to the right side is
Since there is no stable left-handed L portion, the right-handed R state is stable. However, since the right edge line of the upper slit portion U4 of the slit-like opening S4 is the counterclockwise L portion, the right edge line of the lower slit portion D4 of the slit-like opening S4 is stabilized in the counterclockwise L state. Since the same counterclockwise L region is adjacent to the lower slit portion D4 and the upper slit portion U4 at the right edge line of the slit-shaped opening S4, the external pressure is stabilized in the counterclockwise L state.

Then, between the edge line part on the right side of the lower slit part D4 of the slit-like opening S4 and the edge line part on the left side of the slit-like opening S5 (arrow parts in FIG. 8), areas having different rotation directions are adjacent to each other. Therefore, the transmittance is reduced. In the FFS mode liquid crystal display panel, the end of the slit-shaped opening is usually not visually recognized because it is shielded by the light-shielding member. However, it is easy to reduce the transmittance generated between the adjacent slit-shaped openings as described above. Since it can be visually recognized, it appears as a decrease in display image quality.

As in the liquid crystal display element disclosed in Patent Document 3, the slit-shaped opening is bent in a “<” shape, and a wedge shape is bent in a direction in which the angle of inclination with respect to the alignment processing direction is further increased at the bent portion. When the convex portions and concave portions are formed, the generation of disclination can be suppressed, but there is a problem that the display becomes dark because the bent portion becomes large.

The present invention has been made in view of the problems of the prior art as described above. In other words, an object of the present invention is to provide an FFS mode liquid crystal display panel having a slit-like opening bent in a “<” shape, and a peripheral edge where there are regions where the direction of the electric field with respect to the rubbing direction is reversed between positive and negative. Thus, an object of the present invention is to provide an FFS mode liquid crystal display panel that can reduce the problem that disclination remains without being lost even when the pressure is released.

In order to achieve the above object, a liquid crystal display panel of the present invention has a pair of substrates opposed to each other with a liquid crystal layer interposed therebetween, and an upper electrode having a plurality of slit-like openings on one of the pair of substrates. In a liquid crystal display panel comprising the upper electrode and a lower electrode formed on the substrate side through an insulating layer, the slit-shaped opening has a first slit-shaped opening and a second slit-shaped opening on one end side. The first slit-shaped opening and the second slit-shaped opening are coupled to each other with the direction of the electric field reversed from positive to negative with respect to the direction of rubbing treatment, Also on the other end side, the direction of the electric field with respect to the rubbing treatment direction is reversed between positive and negative, and there are 3 places where the direction of the electric field with respect to the rubbing treatment direction is reversed along the same side of the slit-shaped opening. The said coupling portion side exist on why, characterized in that the concave or convex portion of the wedge-shaped narrowing the angle of direction of the electric field relative to the direction of the rubbing treatment is formed.

The liquid crystal display panel according to the present invention includes a pair of substrates disposed to face each other with a liquid crystal layer interposed therebetween, an upper electrode having a plurality of slit-shaped openings on one of the pair of substrates, the upper electrode, and an insulating layer And a lower electrode formed on the substrate side through the FFS mode liquid crystal display panel. In the liquid crystal display panel of the present invention, the slit-shaped opening is formed in a “<” shape in which the first slit-shaped opening portion and the second slit-shaped opening portion are coupled on one end side. The direction of the electric field with respect to the rubbing direction is reversed between positive and negative at the boundary,
Also on the other end side, the direction of the electric field with respect to the direction of the rubbing process is reversed between positive and negative.

On the side where the direction of the electric field with respect to the rubbing treatment direction is reversed in the positive and negative directions along the same side of the slit-shaped opening, physical pressure or the like is applied such as being pressed from the outside. When the liquid crystal alignment is disturbed, the rotation direction of the liquid crystal molecules is the same on the same side of the first slit-shaped opening and the second slit-shaped opening, and the state may be stabilized. In such a state, between the opposing sides of the slits adjacent to each other, the rotation directions of the liquid crystal molecules are opposite to each other, so that disclination occurs and the transmittance may be reduced.

On the other hand, in the liquid crystal display panel according to the present invention, a side connecting portion where there are three or more places where the direction of the electric field with respect to the rubbing treatment direction is reversed positive and negative along the same side of the slit-shaped opening. A wedge-shaped concave portion or convex portion is formed to narrow the angle of the electric field direction with respect to the rubbing treatment direction. When such a configuration is adopted, it is pressed from the outside, etc.
Even if the orientation of the liquid crystal molecules is disturbed due to the application of physical pressure or the like, and the rotation direction of the liquid crystal molecules is reversed, the region where the rotation direction of the liquid crystal molecules is reversed can be converged to the wedge-shaped recess or projection. In addition, this region can be extinguished as soon as the physical pressure or the like disappears.

Therefore, according to the liquid crystal display panel of the present invention, even if it is pressed from the outside, such as physical pressure is applied, the liquid crystal alignment is disturbed and the rotation direction of the liquid crystal molecules may be reversed.
Since the disclination generation region is in the vicinity of the wedge-shaped concave portion or convex portion and can return to the original state in a short time, the decrease in transmittance can be suppressed as in the conventional example.

In the liquid crystal display panel of the present invention, the slit-shaped opening has a side where the direction of the electric field with respect to the rubbing process is reversed between positive and negative at the other end of the first slit-shaped opening and the second slit-shaped opening. It is preferable that a wedge-shaped recess is formed in the connecting portion on the side that is the inner angle side.

When the other end side of the first slit-shaped opening portion and the second slit-shaped opening portion has a side where the direction of the electric field with respect to the rubbing treatment direction is reversed, the inner corner side has a side of the electric field with respect to the rubbing treatment direction. The side where the direction is reversed between positive and negative is the side where there are three or more locations. Therefore, a liquid crystal display panel having the above-described effect can be obtained by forming a wedge-shaped concave portion at the connecting portion of the side on the inner corner side. The “side” in the present invention is used to mean both a straight line and a curved line.

In the liquid crystal display panel of the present invention, the slit-shaped opening has an angle at which the direction of the electric field with respect to the rubbing direction is reversed between positive and negative on the other end side of the first slit-shaped opening and the second slit-shaped opening. It is preferable that a wedge-shaped convex portion is formed at the connecting portion on the side that is on the outer angle side.

When the other end side of the first slit-shaped opening portion and the second slit-shaped opening portion has an angle where the direction of the electric field with respect to the rubbing treatment direction is reversed between positive and negative, the outer corner side has an electric field with respect to the rubbing treatment direction. The side where the direction is reversed between positive and negative is the side where there are three or more locations. Therefore, a liquid crystal display panel having the above-described effect can be obtained by forming a wedge-shaped convex portion at the connecting portion of the side on the outer corner side.

Further, in the liquid crystal display panel of the present invention, the slit-shaped opening is a side where the direction of the electric field with respect to the rubbing process direction is reversed on the other end side of the first slit-shaped opening part or the second slit-shaped opening part. The second slit-shaped opening part or the other end side of the first slit-shaped opening part has an angle at which the direction of the electric field with respect to the rubbing treatment direction is reversed between positive and negative, and the coupling portion on the side on the inner angle side In this case, a wedge-shaped concave portion is formed, and a wedge-shaped convex portion is formed at the coupling portion on the side on the outer corner side.

The other end side of the first slit-shaped opening portion or the second slit-shaped opening portion has a side where the direction of the electric field with respect to the rubbing treatment direction is reversed, and the second slit-shaped opening portion or the first slit-shaped opening portion When the end has an angle where the direction of the electric field with respect to the rubbing direction is reversed between positive and negative, there are places where the direction of the electric field with respect to the rubbing direction is reversed between positive and negative on both the inner corner side and the outer corner side. There are 3 or more sides. In such a configuration, the first slit-shaped opening and the second slit-shaped opening are asymmetric. Therefore, a wedge-shaped concave portion is formed at the joint portion of the side on the inner corner side, and a wedge-shaped convex portion is formed at the joint portion of the side on the outer corner side, whereby a liquid crystal display panel having the above effects can be obtained.

It is a front view which shows the slit-shaped opening of the liquid crystal display panel which concerns on this embodiment. It is sectional drawing along the II-II line of FIG. It is sectional drawing along the III-III line of FIG. It is the schematic diagram which showed rotation of the liquid crystal molecule of the slit-shaped opening of FIG. It is the schematic diagram which showed the rotation direction of the liquid crystal molecule of the slit-shaped opening of FIG. It is a schematic diagram which shows the modification of the liquid crystal display panel which concerns on this embodiment. It is the schematic diagram which showed the rotation direction of the liquid crystal molecule of the slit-shaped opening of the conventional liquid crystal display panel. It is a schematic diagram which shows the disclination production | generation state of the conventional liquid crystal display panel.

The best mode for carrying out the present invention will be described below with reference to the embodiments and drawings. However, the embodiments shown below are not intended to limit the present invention to those described herein. The present invention can be equally applied to various modifications without departing from the technical idea shown in the claims. In each drawing used for the description in this specification, each layer and each member are displayed in different scales so that each layer and each member can be recognized on the drawing. However, it is not necessarily displayed in proportion to the actual dimensions.

FIG. 1 is a front view showing a slit-like opening of the liquid crystal display panel according to the present embodiment. FIG. 2 is a sectional view taken along line II-II in FIG. FIG. 3 is a sectional view taken along line III-III in FIG.
FIG. 4 is a schematic diagram showing the rotation of the liquid crystal molecules in the slit-shaped opening of FIG. FIG. 5 is a schematic diagram showing the rotation direction of the liquid crystal molecules in the slit-shaped opening of FIG. FIG. 6 is a schematic view showing a modification of the liquid crystal display panel according to the present embodiment.

The liquid crystal display panel 10 of the first embodiment operates in the FFS mode, and the configuration of the main part thereof will be described with reference to FIGS. The liquid crystal display panel 10 has a plurality of sub-pixels 11 arranged in a matrix. As shown in FIGS. 2 and 3, the liquid crystal display panel 10 has a liquid crystal layer LC sandwiched between an array substrate AR and a color filter substrate CF. The array substrate AR is based on a first transparent substrate 12 made of transparent insulating glass, quartz, plastic or the like. On the first transparent substrate 12, scanning lines 13 made of opaque metal such as aluminum or molybdenum are formed in the X-axis direction (row direction) in FIG. 1 on the side facing the liquid crystal layer LC.
A gate electrode G extends from the scanning line 13 to the lower left of each subpixel 11.

A transparent gate insulating film 14 made of silicon nitride, silicon oxide or the like is laminated so as to cover the scanning line 13 and the gate electrode G. A semiconductor layer 15 made of amorphous silicon, polycrystalline silicon, or the like is formed on the gate insulating film 14 overlapping the gate electrode G in plan view. A plurality of signal lines 16 made of a metal such as aluminum or molybdenum are formed on the gate insulating film 14 in the Y-axis direction (column direction) in FIG. Each of the areas partitioned by these scanning lines 13 and signal lines 16 becomes a sub-pixel area. This signal line 16
The source electrode S extends from the source electrode S and is in partial contact with the surface of the semiconductor layer 15.

Further, a drain electrode D formed simultaneously with the same material as the signal line 16 and the source electrode S is provided on the gate insulating film 14, and the drain electrode D is disposed in the vicinity of the source electrode S and the semiconductor layer 15. Partially touching. The three sub-pixels R (red), G (green), and B (blue) form one substantially square pixel, and the sub-pixel 11 that divides this into three equal parts has the scanning line 13 as the short side and the signal line 16. Becomes a long rectangle. Gate electrode G, gate insulating film 14, semiconductor layer 15
, Source electrode S, drain electrode D, which is a thin film transistor TF serving as a switching element
T is configured, and this TFT is formed in each sub-pixel 11.

Further, a transparent passivation film 17 made of, for example, silicon nitride or silicon oxide is laminated so as to cover the exposed portions of the signal line 16, the thin film transistor TFT and the gate insulating film 14. Then, a first interlayer film 18 made of a transparent resin material such as a photoresist is laminated so as to cover the passivation film 17. A lower electrode 19 made of a transparent conductive material such as ITO (Indium Thin Oxide) or IZO (Indium Zinc Oxide) is formed so as to cover the first interlayer film 18. The lower electrode 19 operates as a pixel electrode (or a common electrode). Drain electrode through first interlayer film 18 and passivation film 17
A contact hole 20 reaching D is formed, and the lower electrode 19 and the drain electrode D are electrically connected through the contact hole 20. Therefore, this liquid crystal display panel 1
At 0, the lower electrode 19 is manually operated as a pixel electrode.

A transparent interelectrode insulating film 21 made of, for example, silicon nitride or silicon oxide is laminated so as to cover the lower electrode 19. Then, ITO or I is formed so as to cover the interelectrode insulating film 21.
An upper electrode 22 made of a transparent conductive material such as ZO is formed. The upper electrode 22 is connected to a common wiring at the periphery of the display area (both not shown) and operates as a common electrode. As shown in FIG. 1, a plurality of slit-like openings (hereinafter simply referred to as “slits”) 23 are formed in the upper electrode 22. The slit 23 is formed by exposing and etching the upper electrode 22 by photolithography. The specific shape of the slit 23 will be described later. The first alignment film 2 made of polyimide covering the upper electrode 22
4 are stacked. The first alignment film 24 is subjected to liquid crystal direction alignment processing (hereinafter referred to as rubbing processing) in parallel with the extending direction of the signal lines 16.

The color filter substrate CF is based on a second transparent substrate 25 made of transparent insulating glass, quartz, plastic, or the like. The second transparent substrate 25 is formed with a light shielding layer 26 and a color filter layer 27 that transmits light of different colors (for example, R (red), G (green), and B (blue)) for each subpixel. . That is, the light shielding layer 26 is formed so as to overlap the scanning line 13, the signal line 16, the thin film transistor TFT, and the drain electrode D in a plan view. Sub pixel 1
A color filter layer 27 is formed in a region where one light shielding layer 26 is not formed.
An overcoat 28 made of a transparent resin material such as a photoresist is laminated so as to cover the light shielding layer 26 and the color filter layer 27. The overcoat 28 is formed so as to flatten the steps due to the color filter layers 27 of different colors and to block impurities flowing out from the light shielding layer 26 and the color filter layer 27 from entering the liquid crystal layer LC. It is. Second alignment film 29 made of polyimide so as to cover overcoat 28
Is formed. The second alignment film 29 is subjected to a liquid crystal alignment process in the direction opposite to that of the first alignment film 24.

The array substrate AR and the color filter substrate CF thus formed are opposed to each other, a sealing material (not shown) is provided around both substrates, and the substrates are bonded together, and liquid crystal is filled between the substrates. Thus, the liquid crystal display panel 10 according to the first embodiment is obtained. A spacer (not shown) for holding the liquid crystal layer LC at a predetermined thickness is formed on the color filter substrate CF.

With the configuration described above, when a TFT is turned on and a voltage is applied between the lower electrode 19 and the upper electrode 22, an electric field is generated between the electrodes 19 and 22, and the alignment direction of the liquid crystal molecules in the liquid crystal layer LC is changed. Change. As a result, the light transmittance of the liquid crystal layer LC changes and an image is displayed. In addition,
A storage capacitor is incidentally formed by the lower electrode 19, the upper electrode 22, and the interelectrode insulating film 21, and the TFT
When is turned off, the electric field between the electrodes 19 and 22 can be held for a predetermined time.

Next, the specific shape of the slit 23 formed in the upper electrode 22 will be described with reference to FIGS.
It will be described in detail. In the FFS mode liquid crystal display panel 10, the electric field is generated by a potential difference between the upper electrode 22 and the lower electrode 19 positioned below the slit 23. Electric field is array substrate A
It occurs substantially parallel to the surface of R, and the direction of the electric field in plan view is the normal direction of the side of the slit 23. At both ends of the slit 23, the electric field direction is different from the electric field direction of the long side portion of the slit 23.
A reverse twist domain occurs. Since this reverse twist domain cannot display normally, it causes a reduction in aperture ratio.

Moreover, since the area | region for closing the slit 23 exists in the both ends vicinity of the slit 23, an aperture ratio falls further. Since the sub-pixels 11 in the liquid crystal display panel 10 of the present embodiment are vertically long, the number of ends of the slits 23 increases when the slits 23 extend in the horizontal direction. Therefore, in the liquid crystal display panel 10 of the present embodiment, as shown in FIG. 1, the extension direction of the slits 23 is set to the (column axis direction), thereby reducing the number of ends of the slits 23 and the aperture ratio. I try not to lower it.

The extending direction of the slit 23 is inclined by a predetermined angle α (for example, about 5 degrees to about 15 degrees) with respect to the rubbing process direction. Thereby, the liquid crystal molecules can be rotated in the same direction.
When all the slits 23 are clockwise or counterclockwise, the liquid crystal molecules are twisted in the same direction, so that a phenomenon in which the color changes depending on the viewing angle direction appears. This is because the apparent retardation changes depending on the direction of viewing the liquid crystal molecules. In order to reduce this, in the liquid crystal display panel 10 of the present embodiment, a domain in which the extending direction of the slit 23 is inclined by + α with respect to the clockwise direction and a domain by which −α is inclined are provided. That is, it is multi-domain. In the liquid crystal display panel 10 of the present embodiment, the number of domains with different alignment directions is two, but the number of domains with different alignment directions may be increased.

When the slits 23 of domains having different orientation directions are separated, the end portions of the slits 23 are increased, so that the area of a region that cannot be normally displayed increases, and the aperture ratio decreases. Therefore,
In the present invention, the slits 23 are folded in a “<” shape to connect the slits 23 that form domains having different orientation directions. By bending the slit 23 in a “<” shape in this way, the area of a region that cannot be normally displayed is reduced as compared with the case where the slit 23 is separated, so that the aperture ratio can be increased.

As shown in FIG. 1, the first slit S <b> 1 and the second slit S <b> 2 exist in the “<”-shaped slit 23 due to the difference in the shape of the end. The end of the first slit S1 is tapered in a banana shape and protrudes toward the inner corner, and the end of the second slit S2 does not protrude in order to leave the region of the upper electrode 22 between the signal line 16 and the end. As shown in FIGS. 4 and 5, the first slit S
A wedge-shaped recess T1 is formed in the direction of narrowing the width of the slit 23 on the inner corner side of the first connecting portion J1.

In the slit S1, when the wedge-shaped recess T1 is not formed, the side of the inner corner side (the right side in FIG. 4) is the direction of the electric field with respect to the rubbing process direction at the three ends of both end portions E1U and E1D and the coupling portion J1. There is a place where is positive and negative. On the other hand, on the outer angle side (left side in FIG. 4), the place where the direction of the electric field with respect to the rubbing process direction is reversed between positive and negative is one place of the joint portion J1. Therefore, in the slit S1, even if physical pressure or the like is applied from the outside, such as being pressed from the outside, the liquid crystal alignment is disturbed and the rotation direction of the liquid crystal molecules is reversed and stabilized. And the region that is to be converged to the wedge-shaped recess T1,
When the physical pressure or the like is removed, the original state is immediately restored, so that a reduction in luminance can be suppressed.

Further, as shown in FIG. 5, on the outer angle side of the coupling portion J2 of the second slit S2, a slit 23 is provided.
A wedge-shaped convex portion T2 is formed in a direction in which the width of the projection is increased. The first slit S1 is formed by connecting the upper slit portion U1 and the lower slit portion D1 in a “<” shape, and the upper slit portion U1 is at an angle of + α1 (for example, about 5 degrees to about 15 degrees) with respect to the rubbing direction. The lower slit portion D1 extends at an angle of -α1 with respect to the rubbing direction. And the edge part E1U of the upper slit part U1 and the edge part E1D of the lower slit part D1 protrude in a taper to the inner corner side.

In the slit S2, when the wedge-shaped convex portion is not formed, the inner corner side (right side in FIG. 5) has a portion where only the coupling portion J2 and the direction of the electric field with respect to the rubbing direction is reversed. . On the other hand, on the outer angle side (left side in FIG. 5), both ends E2U and E2D and the joint J
There are places where the direction of the electric field with respect to the rubbing treatment direction is reversed between positive and negative at three places. For this reason, in the slit S2, even if physical pressure or the like is applied from the outside, for example, the liquid crystal alignment is disturbed and the rotation direction of the liquid crystal molecules is reversed and stabilized, the rotation direction of the liquid crystal molecules is reversed. In addition to being able to converge on the wedge-shaped convex portion T2, the region immediately returns to the original state as soon as the physical pressure or the like is removed, so that a reduction in luminance can be suppressed.

Note that “OFF” in FIG. 4 indicates the alignment direction of the liquid crystal molecules when no electric field is applied to the liquid crystal molecules, and this direction coincides with the rubbing treatment direction. In addition, “ON” in FIG.
"Indicates the alignment direction of the liquid crystal molecules when an electric field is applied to the liquid crystal molecules, and this direction coincides with the normal line of the edge of the slit 23. As shown in FIG. 4, the rotation direction of the liquid crystal molecules when an electric field is applied to the liquid crystal molecules rotates from the OFF position to the ON position in a direction with a small rotation angle.

FIG. 5 is a diagram showing the rotation direction of the liquid crystal molecules when an electric field is applied to the liquid crystal molecules, and R in the drawing indicates that the rotation direction of the liquid crystal molecules when the electric field is applied is right (clockwise). Indicates L
Indicates left (counterclockwise). Regarding the rotation direction of the liquid crystal molecules when an electric field is applied in the first slit S1, the upper slit portion U1 other than the end portion E1U is a left rotation, and the lower slit portion D1 other than the end portion E1D is a right rotation. Regarding the rotation direction of the liquid crystal molecules in the second slit S2 when an electric field is applied, the upper slit portion U2 other than the end portion E2U is rotated left, and the lower slit portion D2 other than the end portion E2D is rotated clockwise. Here, the first slit S1
Without the concave portion T1 and the convex portion T2 of the second slit S2, the rubbing process is performed on both ends of the inner corner side edge line of the first slit S1 and the outer corner side edge line of the second slit S2, as shown in FIG. There is a region in which the direction of the electric field with respect to the direction of positive and negative is reversed, and the arrow portion in FIG. 8 becomes dark.

In the present invention, by providing recesses or protrusions in the joints J1 and J2, it is possible to prevent the luminance from being lowered by preventing the regions where the direction of the electric field from reversing the direction of the rubbing process exists at both ends of the main edge line. can do. As shown in FIG. 4, the edge line of α1 on the inner angle side is coupled through the recess T1 whose edge line angle is + α2 and −α2 with respect to the rubbing process direction. The angle between the normal and the line has changed. Thereby, since the direction of the electric field is changed, domains having different orientation directions are unlikely to move back and forth, and ripple defects can be reduced.

Further, as shown in FIG. 4, since α2> α1, the rotational force applied to the liquid crystal molecules is larger at the α2 edge line than at the α1 edge line. That is, a recess T1 is provided to narrow the angle of the electric field direction with respect to the rubbing process direction. Therefore, even if the liquid crystal display panel 1 is temporarily pressed to change the rotation angle of the liquid crystal molecules and the disclination increases, a large rotational force is applied to the liquid crystal molecules at the bent portion, so that the original state The ripple can be reduced.

As shown in FIG. 6, the lower slit portion D1 and the second slit S2 of the first slit S1.
In the asymmetrical third slit S3 in which the upper slit portion U2 is combined, there are 3 locations where the direction of the electric field with respect to the rubbing direction is reversed between positive and negative on both the inner angle side and the outer angle side.
It becomes an edge that exists. In such a case, the wedge-shaped convex portion T2 may be formed in the joint portion of the side on the outer angle side, and the wedge-shaped concave portion T1 may be formed in the joint portion of the side on the inner corner side.

In the above embodiment, the slit formed in the upper electrode is an example of a shape extending in a “<” shape along the signal line. However, a horizontal “<” shape is formed along the scanning line. Applicable even when necessary.

DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display panel 11 ... Sub pixel 12 ... Transparent substrate 13 ... Scanning line 14 ... Gate insulating film 15 ... Semiconductor layer 16 ... Signal line 17 ... Passivation film 18 ... Interlayer film
DESCRIPTION OF SYMBOLS 19 ... Lower electrode 20 ... Contact hole 21 ... Interelectrode insulating film 22 ... Upper electrode 23 ... Slit 24 ... Orientation film 25 ... Transparent substrate 26 ... Light shielding layer 27 ... Color filter layer 2
8 ... Overcoat 29 ... Alignment film 33 ... Slit AR ... Array substrate CF ... Color filter substrate D1, D2, D4, D5 ... Lower slit portion U1, U2, U4, U5 ...
Upper slit part E1D, E2D, E4D, E5D ... End E1U, E2U, E4U, E
5U ... end J1-J3 ... coupling part LC ... liquid crystal layer S1-S3 ... slit T1 ... recess
T2 ... convex part

Claims (4)

A pair of substrates disposed opposite to each other with a liquid crystal layer interposed therebetween, an upper electrode having a plurality of slit-like openings on one of the pair of substrates, and formed on the substrate side through the upper electrode and an insulating layer In a liquid crystal display panel provided with a lower electrode,
The slit-like opening is a “<” shape in which the first slit-like opening part and the second slit-like opening part are joined on one end side,
The first slit-shaped opening and the second slit-shaped opening are:
The direction of the electric field with respect to the rubbing direction is reversed between the coupling part and the direction of the electric field with respect to the rubbing direction at the other end.
Along the same side of the slit-shaped opening, there are three or more places where the direction of the electric field with respect to the direction of the rubbing process is reversed between the positive and negative directions. A liquid crystal display panel, wherein a wedge-shaped concave portion or convex portion that narrows the angle of the electric field direction is formed. The slit-shaped opening has a side where the direction of the electric field with respect to the rubbing treatment direction is reversed on the other end side of the first slit-shaped opening portion and the second slit-shaped opening portion, and the combination of the sides on the inner angle side The liquid crystal display panel according to claim 1, wherein a wedge-shaped recess is formed in the portion. The slit-shaped opening has an angle at which the direction of the electric field with respect to the rubbing direction is reversed on the other end side of the first slit-shaped opening portion and the second slit-shaped opening portion, and the combination of the sides on the outer angle side The liquid crystal display panel according to claim 1, wherein a wedge-shaped convex portion is formed on the portion. The slit-shaped opening has a side where the direction of the electric field with respect to the rubbing treatment direction is reversed on the other end side of the first slit-shaped opening or the second slit-shaped opening, and the second slit-shaped opening Alternatively, the other end side of the first slit-shaped opening portion has an angle at which the direction of the electric field with respect to the rubbing direction is reversed, and a wedge-shaped recess is formed in the coupling portion on the side that is the inner angle side, The liquid crystal display panel according to claim 1, wherein a wedge-shaped convex portion is formed at the coupling portion on the side.

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