WO2014003417A1

WO2014003417A1 - Liquid crystal display device

Info

Publication number: WO2014003417A1
Application number: PCT/KR2013/005609
Authority: WO
Inventors: 김재훈; 이유진
Original assignee: 한양대학교 산학협력단
Priority date: 2012-06-25
Filing date: 2013-06-25
Publication date: 2014-01-03

Abstract

Provided are a liquid crystal display device and a method for driving same. The liquid crystal display device comprises the liquid crystal display device in a PVA mode, an LVA mode, an FFS mode, and in an IPS mode. The liquid crystal display device comprises 1 to 50 wt.% of an achiral smectic liquid crystal, and a remainder of a nematic liquid crystal. The liquid crystal device comprises 3 to 50 wt.% of a smectic liquid crystal and a remainder of the nematic liquid crystal, wherein the smectic liquid crystal comprises a liquid crystal layer, comprising 70 to 97 wt.% of an achiral smectic liquid crystal, and 3 to 30 wt.% of a chiral smectic liquid crystal.

Description

Liquid crystal display

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device including a liquid crystal layer having a nematic liquid crystal and a smectic liquid crystal.

Liquid crystal display devices are one of the flat panel display devices most widely used at present, and studies for high quality, high brightness, and large size are being actively conducted. As a part of the research, the structure of electrodes in the liquid crystal display device has been diversified and complicated for the high quality, high brightness and large size of the liquid crystal display device. When a driving voltage is applied to these electrodes, the arrangement of the liquid crystal molecules of the liquid crystal layer is changed by an applied electric field, and the arrangement of the liquid crystal molecules is uneven and unstable by the electrodes. Uneven and unstable arrangement of the liquid crystal molecules is caused by a problem of lowering the brightness of the liquid crystal display.

An object of the present invention is to provide a liquid crystal display device having improved luminance.

The problem to be solved by the present invention is not limited to the above-mentioned problem, another task that is not mentioned will be clearly understood by those skilled in the art from the following description.

One embodiment according to the inventive concept provides a liquid crystal display device. The liquid crystal display device includes a first substrate; A second substrate spaced apart from and facing the first substrate; A liquid crystal layer disposed between the first and second substrates; A first electrode disposed between the first substrate and the liquid crystal layer and having a first slit; And a second electrode disposed between the liquid crystal layer and the second substrate, the second electrode having a second slit, wherein the liquid crystal layer comprises: 1 to 50 wt% of an achiral smectic liquid crystal; And extra nematic liquid crystals.

Another embodiment according to the inventive concept provides a liquid crystal display device. The liquid crystal display device includes a first substrate; A second substrate spaced apart from and facing the first substrate; A liquid crystal layer disposed between the first and second substrates; A first electrode disposed between the first substrate and the liquid crystal layer and having a first slit; And a second electrode disposed between the liquid crystal layer and the second substrate and having a second slit, wherein the liquid crystal layer comprises: 3 to 50 wt% smectic liquid crystal; And an extra nematic liquid crystal, wherein the smectic liquid crystal comprises: 70 to 97% by weight of a non-chiral smectic liquid crystal; And 3 to 30% by weight of a chiral smectic liquid crystal.

Another embodiment according to the concept of the present invention provides a liquid crystal display device. The liquid crystal display may include a first electrode and a second electrode spaced apart from each other; And a plurality of liquid crystal molecules having a first alignment direction perpendicular to a surface of the first or second electrode when the potential difference is filled between the first and second electrodes and there is no potential difference between the first and second electrodes. Including a liquid crystal layer, wherein the liquid crystal layer, 1 to 50% by weight of an achiral smectic liquid crystal (achiral smectic liquid crystal); And an extra nematic liquid crystal, wherein when a potential difference occurs between the first and second electrodes, the plurality of liquid crystal molecules are substantially parallel to an extension direction of the first or second electrode. Performing a changing operation to have a second alignment direction, wherein the changing operation of the liquid crystal molecules includes a first alignment step and a second alignment step that occur sequentially, and in the first alignment step, the liquid crystal molecules Are changed to have a third alignment direction different from the first or second alignment direction, and in the second alignment step, the liquid crystal molecules of the third alignment direction are changed to have the second alignment direction.

Another embodiment according to the concept of the present invention provides a liquid crystal display device. The liquid crystal display may include a first electrode and a second electrode spaced apart from each other; And a plurality of liquid crystal molecules having a first alignment direction perpendicular to a surface of the first or second electrode when the potential difference is filled between the first and second electrodes and there is no potential difference between the first and second electrodes. Including a liquid crystal layer, wherein the liquid crystal layer, Smectic liquid crystal 3 to 50% by weight; And an extra nematic liquid crystal, wherein the smectic liquid crystal comprises: 70 to 97% by weight of a non-chiral smectic liquid crystal; And 3 to 30% by weight of a chiral smectic liquid crystal, and when a potential difference occurs between the first and second electrodes, the alignment of liquid crystal molecules in the liquid crystal layer filled between the first and second electrodes The operation of changing the second alignment direction substantially parallel to the extending direction of the first or second electrode, wherein the changing operation of the liquid crystal molecules, the first alignment step and the second alignment step And in the first alignment step, the liquid crystal molecules are changed to have a third alignment direction different from the first or second alignment direction, and in the second alignment step, the liquid crystal molecules in the third alignment direction It changes so that it may have a said 2nd orientation direction.

Another embodiment according to the concept of the present invention provides a liquid crystal display device. The liquid crystal display device includes a first substrate; A second substrate spaced apart from and facing the first substrate; A liquid crystal layer disposed between the first and second substrates; A plate-shaped common electrode disposed between the first substrate and the liquid crystal layer; And a pixel electrode having a pattern defining an opening disposed between the common electrode and the liquid crystal layer, wherein the liquid crystal layer comprises: 1 to 50 wt% of an achiral smectic liquid crystal; And extra nematic liquid crystals.

Another embodiment according to the concept of the present invention provides a liquid crystal display device. The liquid crystal display device includes a first substrate; A second substrate spaced apart from and facing the first substrate; A liquid crystal layer disposed between the first and second substrates; A plate-shaped common electrode disposed between the first substrate and the liquid crystal layer; And a pixel electrode having a pattern defining an opening disposed between the common electrode and the liquid crystal layer, wherein the liquid crystal layer comprises: 3 to 50 wt% smectic liquid crystal; And an extra nematic liquid crystal, wherein the smectic liquid crystal comprises: 70 to 97% by weight of a non-chiral smectic liquid crystal; And 3 to 30% by weight of a chiral smectic liquid crystal.

Another embodiment according to the concept of the present invention provides a liquid crystal display device. The liquid crystal display device includes a first substrate; A second substrate spaced apart from and facing the first substrate; A liquid crystal layer disposed between the first and second substrates; A common electrode disposed between the first substrate and the liquid crystal layer and having a first pattern; And a pixel electrode disposed between the first substrate and the liquid crystal layer and having a second pattern that does not overlap the first pattern, wherein the liquid crystal layer comprises 1 to 50 weights of achiral smectic liquid crystals. %; And extra nematic liquid crystals.

Another embodiment according to the concept of the present invention provides a liquid crystal display device. The liquid crystal display device includes a first substrate; A second substrate spaced apart from and facing the first substrate; A liquid crystal layer disposed between the first and second substrates; A common electrode disposed between the first substrate and the liquid crystal layer and having a first pattern; And a pixel electrode disposed between the first substrate and the liquid crystal layer and having a second pattern that does not overlap the first pattern, wherein the liquid crystal layer comprises: 3 to 50 wt% smectic liquid crystal; And an extra nematic liquid crystal, wherein the smectic liquid crystal comprises: 70 to 97% by weight of a non-chiral smectic liquid crystal; And 3 to 30% by weight of a chiral smectic liquid crystal.

According to the exemplary embodiment of the present invention, the liquid crystal display may include a liquid crystal layer having a nematic liquid crystal and a non-chiral smectic liquid crystal. In addition, the liquid crystal layer according to the embodiment of the present invention may further include a chiral liquid crystal. In the liquid crystal display including the liquid crystal layer, alignment uniformity and stability of liquid crystal molecules in the liquid crystal layer may be improved to improve transmittance of the liquid crystal display.

For a more complete understanding and help of the invention, reference is given to the following description together with the accompanying drawings and reference numbers are shown below.

1 is a plan view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

2 is a cross-sectional view for describing a liquid crystal display according to an exemplary embodiment of the present invention.

3A to 3I are plan views illustrating structures of first or second electrodes according to embodiments of the present invention.

4 is a graph showing the electrical characteristics of the liquid crystal layer according to an embodiment of the present invention.

5 is a graph comparing the transmittance of the liquid crystal display of Comparative Example 1, Examples 1 to 7.

6A is a graph illustrating the transmittance of the liquid crystal display of Comparative Example 1 and the transmittance according to the amount of non-chiral components in the liquid crystal layer of the liquid crystal display of Examples 1 to 7. FIG.

FIG. 6B is a graph showing the transmittance of the liquid crystal display of Comparative Example 1 and the transmittance according to the amount of chiral components in the liquid crystal layer of the liquid crystal display of Examples 1 to 7. FIG.

7 is a graph comparing response speeds of the liquid crystal display of Comparative Example 1 and Examples 1 to 7. FIG.

FIG. 8 is a graph illustrating the rising time and the polling time of the liquid crystal display of Comparative Example 1 and the rising time and the polling time of the liquid crystal display of Examples 1 to 7 according to the amount of non-chiral component.

9A is a graph illustrating the rising time of the liquid crystal display of Comparative Example 1 and Examples 1 to 7. FIG.

9B is a graph illustrating the polling time of the liquid crystal display of Comparative Example 1 and Examples 1 to 7. FIG.

10A to 10H are white textures of the liquid crystal display of Comparative Example 1 and Embodiments 1 to 7. FIG.

11A through 11H are black textures of the liquid crystal display of Comparative Example 1 and Embodiments 1 through 7.

12A and 12B are graphs showing gray levels of the textures of Comparative Example 1 and Examples 1 to 7. FIG.

13A and 13B are graphs showing transmittances according to distances of the textures of Comparative Example 1 and Examples 1 to 7. FIG.

14A, 15A, and 16A are perspective views illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

14B, 15B, and 16B are cross-sectional views illustrating a liquid crystal display device according to an exemplary embodiment of the present invention.

14C, 15C, and 16C are plan views illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

17A and 17B are plan views and cross-sectional views for describing a liquid crystal display according to an exemplary embodiment of the present invention.

18A to 18F are plan views illustrating structures of first and second electrodes according to example embodiments.

19 is a graph comparing transmittances of the liquid crystal display of Comparative Example 2 and Examples 8 to 14.

20A is a graph showing the transmittance of the liquid crystal display of Comparative Example 2 and the transmittance according to the amount of non-chiral component in the liquid crystal layer of the liquid crystal display of Examples 8 to 14. FIG.

20B is a graph showing the transmittance of the liquid crystal display of Comparative Example 2 and the transmittance according to the amount of chiral components in the liquid crystal layer of the liquid crystal display of Examples 8 to 14. FIG.

21A to 21H and 22A to 22H are textures of the liquid crystal display devices of Comparative Example 2 and Examples 8 to 14.

23A and 23B are graphs showing gray levels of the textures of Comparative Example 2 and Examples 8 to 14. FIG.

24A and 24B are graphs showing transmittances according to distances of the textures of Comparative Examples 2 and 8 to 14.

25 and 26 are plan views and cross-sectional views for describing a liquid crystal display according to an exemplary embodiment of the present invention.

27 is a graph comparing the transmittances of the liquid crystal display of Comparative Example 3 and Examples 15 to 21 according to the applied voltage.

28A is a graph illustrating the transmittance of the liquid crystal display of Comparative Example 3 and the transmittance according to the amount of non-chiral component in the liquid crystal layer of the liquid crystal display of Examples 15 to 21. FIG.

28B is a graph showing the transmittance of the liquid crystal display of Comparative Example 3 and the transmittance according to the amount of chiral components in the liquid crystal layer of the liquid crystal display of Examples 15 to 21. FIG.

29A is a graph comparing the response speeds of the liquid crystal displays of Comparative Example 3 and Examples 15 to 21. FIG.

29B is a graph illustrating the rising time and the polling time of the liquid crystal display of Comparative Example 3 and the rising time and the polling time of the liquid crystal display of Examples 15 to 21 according to the amount of non-chiral component.

29C is a graph illustrating the rising time of Comparative Example 3 and the liquid crystal display devices of Examples 15 to 21 according to the applied voltage.

29D is a graph illustrating the polling time of Comparative Example 3 and the liquid crystal display devices of Examples 15 to 21 according to the applied voltage.

30A to 30H and 31A to 31H are textures of the liquid crystal display of Comparative Example 3 and Embodiments 15 to 21.

32A and 32B are graphs showing the transmittance according to the distances of the textures of Comparative Example 3 and Examples 15 to 21. FIG.

33A and 33B are graphs showing transmittances according to distances of the textures of Comparative Example 3 and Examples 15 to 21. FIG.

34 and 35 are plan views and cross-sectional views for describing a liquid crystal display according to an exemplary embodiment of the present invention.

36 is a graph comparing the transmittances of the liquid crystal display of Comparative Example 4 and Examples 22 to 28 according to the applied voltage.

37A is a graph illustrating the transmittance of the liquid crystal display of Comparative Example 4 and the transmittance according to the amount of non-chiral components in the liquid crystal layer of the liquid crystal display of Examples 22 to 28. FIG.

37B is a graph showing the transmittance of the liquid crystal display of Comparative Example 4 and the transmittance according to the amount of chiral components in the liquid crystal layer of the liquid crystal display of Examples 22 to 28. FIG.

38A is a graph comparing response speeds of liquid crystal display devices of Comparative Example 4 and Examples 22 to 28. FIG.

38B is a graph illustrating the rising time and the falling time of the liquid crystal display of Comparative Example 4 and the rising time and the falling time of the liquid crystal display of Examples 22 to 28 according to the amount of non-chiral component.

38C is a graph illustrating the rising time of Comparative Example 4 and the liquid crystal display devices of Examples 22 to 28 according to the applied voltage.

38D is a graph illustrating the polling time of Comparative Example 4 and the liquid crystal display devices of Examples 22 to 28 according to the applied voltage.

39A to 39H and 40A to 40H are textures of the liquid crystal display of Comparative Example 4 and Embodiments 22 to 28.

41A and 41B are graphs showing transmittances according to distances of the textures of Comparative Example 4 and Examples 22 to 28. FIG.

42A and 42B are graphs showing transmittances according to distances of the textures of Comparative Examples 4 and 22 to 28. FIG.

In order to fully understand the constitution and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various forms and various changes may be made. Only, the description of the embodiments are provided to make the disclosure of the present invention complete, and to provide a complete scope of the invention to those skilled in the art. Those skilled in the art will understand that the concept of the present invention may be carried out in any suitable environment.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, including and / or comprising include components, steps, operations, and / or devices mentioned excludes the presence or addition of one or more other components, steps, operations, and / or devices. I never do that.

Where it is mentioned herein that a film (or layer) is on another film (or layer) or substrate, it may be formed directly on another film (or layer) or substrate or a third film ( Or layers) may be interposed.

Although terms such as first, second, third, etc. are used to describe various regions, films (or layers), etc. in various embodiments of the present specification, these regions, films should not be limited by these terms. do. These terms are only used to distinguish any given region or film (or layer) from other regions or films (or layers). Therefore, the film quality referred to as the first film quality in one embodiment may be referred to as the second film quality in other embodiments. Each embodiment described and illustrated herein also includes its complementary embodiment. Portions denoted by like reference numerals denote like elements throughout the specification.

Unless otherwise defined, terms used in the embodiments of the present invention may be interpreted as meanings commonly known to those of ordinary skill in the art.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[[액정 표시 장치 PVA 모드]][[Liquid Crystal Display PVA Mode]]

1 and 2 are a plan view and a cross-sectional view for describing a liquid crystal display according to an exemplary embodiment of the present invention.

1 and 2, the liquid crystal display includes a first display panel 100, a second display panel 200 spaced apart from and facing the first display panel 100, and the first and second display panels. It may include a liquid crystal layer 300 disposed between (100, 200). The liquid crystal display may further include a first polarizer 400 and a second polarizer 450 having a transmission axis perpendicular to the transmission axis of the first polarizer 400.

The first display panel 100 may include a first substrate 110, a thin film transistor (TFT), and a first electrode 130. The first substrate 110 may include a transparent insulating material such as glass.

The thin film transistor may be disposed on one surface of the first substrate 110. The thin film transistor TFT may include a gate electrode 112, a gate insulating layer 114, a semiconductor 116, a source electrode 122, and a drain electrode sequentially stacked. electrode, 124). The gate electrode 112 may include a single layer or multiple layers of metals or metal alloys, and the gate insulating layer 114 may include silicon oxide, silicon nitride, or silicon oxynitride. The intrinsic semiconductor 116 may include amorphous silicon. The source electrode 122 and the drain electrode 124 may be spaced apart from each other on the intrinsic semiconductor 116. A channel of the thin film transistor TFT may be formed in the intrinsic semiconductor 116 between the source electrode 122 and the drain electrode 124. The source electrode 122 may be electrically connected to a data line DL and may receive a data voltage from the data line DL. The drain electrode 124 may be electrically connected to the first electrode 130.

In example embodiments, the thin film transistor TFT may further include ohmic contacts 118 and 120 disposed between the intrinsic semiconductor 116 and the source and drain

electrodes

122 and 124. The ohmic contacts 118 and 120 may include silicide or n ⁺ hydrogenated amorphous silicon doped with a high concentration of n-type impurities.

A first insulating layer 126 having a contact hole 128 may be formed on the thin film transistor TFT. The first insulating layer 126 may include an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or an organic insulating material such as resin. The contact hole 128 may expose an upper surface of the drain electrode 124.

The first electrode 130 may be formed on the first insulating layer 126. The first electrode 130 may be a pixel electrode. The first electrode 130 may be electrically connected to the drain electrode by a contact hole. The first electrode 130 may receive a data voltage from the drain electrode. The first electrode 130 may include a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

According to an embodiment of the present invention, the first electrode 130 may include domain dividing means, for example,

first slits

132a and 132b. The

first slits

132a and 132b may be portions in which the first electrode 130 is removed so that the first electrode 130 has a pattern. When the voltage is applied to the first electrode 130 and the second electrode 230, the

first slits

132a and 132b generate an electric field between the first and

second electrodes

130 and 230. By the

first slits

132a and 132b, the electric field may be formed to be inclined simultaneously with vertical and horizontal components instead of perpendicular to the surface of the first substrate 110. In another embodiment of the present invention, the domain dividing means may have a protrusion shape which is formed on the first electrode 130 and protrudes from the first electrode 130 in the direction of the liquid crystal layer 300.

According to the structures of the

first slits

132a and 132b, the first electrode 130 may have various structures. The structure of the

first slits

132a and 132b of the first electrode 130 will be described in detail below.

According to another embodiment of the present invention, the first display panel 100 may further include a first alignment layer 140 between the first electrode 130 and the liquid crystal layer 300. The first alignment layer 140 may pre-tilt the liquid crystal molecules in the liquid crystal layer 300 in one direction. According to one embodiment, the first alignment layer 140 is a group consisting of poly-amic acid, polyimide, lecithin, nylon, polyvinylalcohol (PVA). It may include at least one selected from. In another embodiment, the first alignment layer 140 may further include a reactive mesogen material.

The first polarizer 400 may be disposed on the other surface of the first substrate 110. The other surface of the first substrate 110 may be a surface corresponding to the one surface.

The second display panel 200 may include a second substrate 210 and a second electrode 230. The second substrate 210 may include a transparent insulating material such as glass.

The second electrode 230 may be disposed on one surface of the second substrate 210, and one surface of the second substrate 210 may be a surface facing the first display panel 100. The second electrode 230 may be a common electrode. The second electrode 230 may include a transparent conductive material such as ITO or IZO.

According to an embodiment of the present invention, the second electrode 230 may include domain dividing means, for example,

second slits

232a and 232b. The

second slits

232a and 232b may be portions in which the second electrode 230 is removed to allow the second electrode 230 to have a pattern. When the voltage is applied to the first and

second electrodes

130 and 230, the

second slits

232a and 232b generate an electric field between the first and

second electrodes

130 and 230. By the

second slits

232a and 232b, the electric field may be formed to be inclined simultaneously with vertical and horizontal components instead of perpendicular to the surface of the second substrate 210. According to another embodiment of the present invention, the second electrode 230 may have a protrusion shape protruding from the second electrode 230 toward the liquid crystal layer 300.

According to the structures of the

second slits

232a and 232b, the second electrode 230 may have various structures. The structure of the

second slits

232a and 232b of the second electrode 230 will be described in detail below.

According to embodiments of the present invention, the liquid crystal display may be a liquid crystal display in a patterned vertical alignment (PVA) mode. Therefore, although the first electrode 130 having the

first slits

132a and 132b and the second electrode 230 having the

second slits

232a and 232b face each other, the

first slits

132a and 132b do not face each other. And the

second slits

232a and 232b do not face each other. For example, the first electrode 130 having the

first slits

132a and 132b and the second electrode 230 having the

second slits

232a and 232b may have substantially the same structure. The first and

second electrodes

130 and 230 may be disposed so that the

slits

132a and 132b and the

second slits

232a and 232b do not face each other. As another example, the first and

second electrodes

130 and 230 may have different structures, and the

first slits

132a and 132b of the first electrode 130 and the second electrode 230 may be formed. The two

slits

232a and 232b may not face each other. In addition, the

first slits

132a and 132b and the

second slits

232a and 232b may be spaced apart from each other without substantially overlapping each other in a plan view. The

first slits

132a and 132b and the

second slits

232a and 232b may be alternated when viewed in a plan view.

According to embodiments of the present invention, as described above, a voltage is applied by the

first slits

132a and 132b and the

second slits

232a and 232b of the first and

second electrodes

130 and 230. An inclined electric field may be formed between the first and

second electrodes

130 and 230. As a result, multi-domains D1 to D4 may be formed in one pixel. Referring to FIG. 1, in the present embodiment, liquid crystal molecules are arranged in four directions, whereby four domains D1 to D4 may be formed in one pixel. However, in the present invention, it does not limit the number of domains formed in the pixel.

In example embodiments, the second display panel 200 may further include a color filter 212. The color filter 212 may be disposed between the second substrate 210 and the second electrode 230. In addition, a light blocking member 214 may be disposed on one surface of the second substrate 210, and the color filter 212 may be formed in each area defined by the light blocking member 214. The color filter 212 may be protected by the second insulating layer 216. In the present exemplary embodiment, the color filter 212 is described as being disposed on the second display panel 200, but the color filter 212 may be disposed on the first display panel 100. In the present invention, the position of the color filter 212 is not limited.

According to another embodiment of the present invention, the second display panel 200 may further include a second alignment layer 240 between the second electrode 230 and the liquid crystal layer 300. The second alignment layer 240 may initially align the liquid crystal molecules in the liquid crystal layer 300 in one direction. According to one embodiment, the second alignment layer 240 is a group consisting of poly-amic acid, polyimide, lecithin, nylon, polyvinylalcohol (PVA). It may include at least one selected from. In another embodiment, the second alignment layer 240 may further include a reactive mesogen material.

The second polarizer 450 may be disposed on the other surface of the second substrate 210. The other surface of the second substrate 210 may be a surface corresponding to the one surface. The second polarizer 450 may pass a linear polarization component that vibrates in a vertical direction among the light passing through the first polarizer 400.

The liquid crystal layer 300 may fill between the first and

second display panels

100 and 200. According to an embodiment, the liquid crystal layer 300 may include a nematic liquid crystal and an achiral smectic liquid crystal. According to another embodiment, the liquid crystal layer 300 may include a nematic liquid crystal and a smectic liquid crystal. Description of the liquid crystal layer 300 will be described in detail below.

According to an embodiment of the present invention, the liquid crystal display may further include an optical compensation film 430. The optical compensation film 430 may be disposed between the second polarizing plate 450 and the second substrate 210. When the liquid crystal molecules maintain the vertical alignment state, when viewed from the front, the polarization axes of the first polarizing plate 400 and the second polarizing plate 450 are perpendicular to each other so that light leakage does not occur, but when viewed from the side, the first and second polarizing plates Light leakage may occur because the polarization angle of the polarization axes of the fields 400 and 450 is increased. In order to compensate for the light leakage, an optical compensation film 430 such as a biaxial film or a uniaxial film may be disposed.

As described above, since the liquid crystal layer 300 of the liquid crystal display of the PVA mode includes the ferroelectric liquid crystal, the alignment of the liquid crystal layer in addition to the nematic liquid crystal can be improved and the stability of the alignment can be improved. Therefore, the luminance of the liquid crystal display including the liquid crystal layer 300 may be improved. In addition, by further including a reactive mesogen material in at least one of the first and second alignment layers 140 and 240, the alignment speed of the liquid crystal molecules in the liquid crystal layer 300 is increased, and the angle of the alignment is also increased, thereby providing optical characteristics. This can be improved.

Hereinafter, the structures of the first and

second electrodes

130 and 230 will be described in detail.

The electrode structure described below is representatively described as an example of the first electrode 130, but the second electrode 230 may have one of the following electrode structures. As described above, if the

first slits

132a and 132b and the

second slits

232a and 232b do not face each other, the structures of the first and second electrodes may be the same or different, and the structure may be variously changed. It is possible.

3A to 3I are plan views illustrating structures of the first and

second electrodes

130 and 230 according to embodiments of the present invention.

Referring to FIG. 3A, the first electrode 130 may have a Chevron pattern. The

first slits

132a and 132b of the first electrode 130 have a V-shape, and have a first line 132a extending in the first direction D1 and a second crossing the first direction D1. The second line 132b extending in the direction D2 may be connected.

Referring to FIG. 3B, the first electrode 130 may have a modified Chevron pattern. The structure of the

first slits

132a and 132b is similar to that shown in FIG. 3A, but the middle of the first line 132a is cut by the first electrode 130 and the middle of the second line 132b. It may have a structure cut by the first electrode 130.

Referring to FIG. 3C, the first electrode 130 may have an X-shaped pattern. The structures of the

first slits

132a and 132b include a first line 132a extending in the first direction D1 and a second line 132b extending in the second direction D2 crossing the first direction D1. ) May be included. Unlike FIG. 3A, the first and

second lines

132a and 132b are not connected to each other.

Referring to FIG. 3D, the first electrode 130 may have a stripe pattern. The structure of the first slit 132 may have a form in which lines extending in one direction are repeatedly provided in parallel with each other.

Referring to FIG. 3E, the first electrode 130 may have a grid pattern. The structures of the

first slits

132a and 132b include a first line 132a extending in a first direction D1 and a second line extending in a second direction D2 perpendicular to the first direction D1 ( 132b) may be connected to the structure.

Referring to FIG. 3F, the first electrode 130 may have square patterns, and each of the square patterns may include four triangles divided into diagonals of the square pattern. The structures of the

first slits

132a, 132b, and 132c may be divided into four rectangular patterns and four triangles within the rectangular patterns. More specifically, the

first slits

132a, 132b, and 132c may include a first line 132a extending in the first direction D1 and a second extension D2 different from the first direction D1. And a third line 132c extending in a third direction D3 that intersects the second line 132b and the second direction D2, and the first and

second lines

132a and 132b each other. The first and

third lines

132a and 132c may be connected to each other.

Referring to FIG. 3G, the first electrode 130 may have square patterns, and each of the square patterns may include two triangles divided diagonally of the square pattern. The structures of the

first slits

132a and 132b may divide the rectangular pattern and divide the two triangles in the rectangular patterns. More specifically, the first slit includes a first line 132a extending in the first direction D1 and a second line 132b extending in a second direction D2 different from the first direction D1. can do. The first and

second lines

132a and 132b may be connected to each other.

Referring to FIG. 3H, the first electrode 130 may have square patterns and may include a circular first slit 132a in the square pattern. In FIG. 3H, the first slit 132a in the square pattern is circular, but the first slit 132a may be polygonal. In addition, the first slit may further include a structure 132b that divides the square patterns.

Referring to FIG. 3I, the first electrode 130 may include a plurality of circular first slits 132. The first slits 132 may be spaced apart from each other at equal intervals and arranged in rows / columns. In FIG. 3I, the first slits 132 are shown in a circular shape, but the first slits 132 may be polygonal.

Hereinafter, the liquid crystal layer will be described in detail.

(액정층_제1 실시예)(Liquid Crystal Layer _ First Embodiment)

The liquid crystal layer according to the embodiments of the present invention may include a nematic liquid crystal and a non-chiral smectic liquid crystal.

The liquid crystal layer may include about 1 wt% to about 50 wt% non-chiral smectic liquid crystal and about 50 wt% to about 99 wt% nematic liquid crystal. When the non-chiral smectic liquid crystal is about 1% by weight or less of the total amount of the liquid crystal layer, the liquid crystal alignment of the liquid crystal layer may be unstable. In addition, when the non-chiral smectic liquid crystal exceeds about 50% by weight of the total amount of the liquid crystal layer, the viscosity of the liquid crystal layer may increase, resulting in a slow response time of the display device including the liquid crystal layer. More preferably, the liquid crystal layer may include about 1% by weight to about 35% by weight of a non-chiral smectic liquid crystal.

According to one embodiment, the amount of non-chiral smectic liquid crystal in the liquid crystal layer may be determined by the viscosity of the non-chiral smectic liquid crystal. When the viscosity of the non-chiral smectic liquid crystal is low, the non-chiral smectic liquid crystal in the liquid crystal layer may include about 50% by weight or more. On the other hand, when the viscosity of the non-chiral smectic liquid crystal is high, it may be desirable to maintain the total viscosity of the liquid crystal layer at about 35% by weight or less.

According to an embodiment, the nematic liquid crystal may include a negative nematic liquid crystal having negative dielectric anisotropy. According to another embodiment, the nematic liquid crystal may include a nematic liquid crystal having negative anisotropy and a positive nematic liquid crystal having positive dielectric anisotropy. The nematic liquid crystal having the positive dielectric anisotropy may occupy about 10% by weight of the nematic liquid crystal.

Hereinafter, exemplary materials of the nematic liquid crystal and the non-chiral smectic liquid crystal will be described. The exemplary materials described below do not limit the nematic liquid crystal and the non-chiral smectic liquid crystal of the present invention to this.

First, the characteristics of nematic liquid crystals will be briefly described, and examples of nematic liquid crystals having negative dielectric anisotropy and nematic liquid crystals having positive dielectric anisotropy will be classified.

Nematic liquid crystals form liquid crystals in which the elongated molecules of the liquid crystal have irregular positions of each other but their long axes are directed in a constant direction. Since each molecule of the nematic liquid crystal can freely move in the long axis direction, the viscosity is small and easily flows. Since the directions of the nematic molecules are substantially the same in the up and down directions, the polarization is canceled and generally does not exhibit ferroelectricity. In the direction perpendicular to the axial direction of the molecules of the liquid crystal, physical properties are very different. Therefore, nematic liquid crystal is a material having optical anisotropy. If the difference between the dielectric anisotropy parallel to the axial direction and the dielectric anisotropy perpendicular to the axial direction (Δε) is less than zero, it is called a nematic liquid crystal with negative dielectric anisotropy. It is called.

Nematic liquid crystals with negative dielectric anisotropy

According to an embodiment, the nematic liquid crystal having negative dielectric anisotropy may include nematic liquid crystal molecules having negative dielectric anisotropy. In one aspect, the nematic liquid crystal molecules having negative dielectric anisotropy may be a single type. In another aspect, the nematic liquid crystal molecules having negative dielectric anisotropy may be of different kinds from each other. For example, the nematic liquid crystal molecules having negative dielectric anisotropy may include liquid crystal molecules having first dielectric anisotropy and liquid crystal molecules having second dielectric anisotropy. In this case, the second dielectric anisotropy may be different from the first dielectric anisotropy. At least one of the first dielectric anisotropy and the second dielectric anisotropy may have dielectric anisotropy having negative anisotropy. The overall dielectric anisotropy of the nematic liquid crystal molecules including the liquid crystal molecules having the first dielectric anisotropy and the liquid crystal molecules having the second dielectric anisotropy may be negative.

According to another embodiment, the nematic liquid crystal having negative dielectric anisotropy may include nematic liquid crystal molecules and base liquid crystal molecules having negative dielectric anisotropy. Each of the base liquid crystal molecules may include at least one selected from the group consisting of liquid crystal molecules having negative dielectric anisotropy, liquid crystal molecules having positive dielectric anisotropy, neutral liquid crystal molecules, chiral liquid crystal molecules, and non-chiral liquid crystal molecules. Can be. In one aspect, the nematic liquid crystal having negative dielectric anisotropy may include nematic liquid crystal molecules having one kind of negative dielectric anisotropy and base molecules. In another aspect, the nematic liquid crystal having negative dielectric anisotropy may include liquid crystal molecules having various kinds of negative dielectric anisotropy and base liquid crystal molecules.

Hereinafter, examples of nematic liquid crystals having negative dielectric anisotropy will be listed and described. The following materials may be used alone or in combination.

The negative liquid crystal having negative dielectric anisotropy may include a halogen group, a cyanide group, or an isocyanate group nematic liquid crystal. The nematic liquid crystal having negative dielectric anisotropy may be used alone or in combination with a halogen group, a cyanide group, or an isocyanate group nematic liquid crystal. As described above, the nematic liquid crystal having negative dielectric anisotropy may further include base liquid crystal molecules.

The nematic liquid crystal having a halogen-based negative dielectric anisotropy may include a fluorine group, a chlorine group, or a bromine group material, and may have a single or polycyclic structure.

Nematic liquid crystals having a negative dielectric anisotropy of a halogen-based bicyclic structure may be represented by the following

Chemical Formulas

1 and 2.

Formula 1

Formula 2

In formulas (1) and (2), R is alkyl having 1 to 15 carbon atoms, or alkoxy, wherein hydrogen may be substituted with CN, CF ₃ , or halogen, and CH ₂ -group can be substituted with -CH = CH-, -O-, -CO-, -COO-, -OOC-, -O-OC-O- or -S-), X independently of each other Halogen, halogenated alkyl with 1 to 15 carbon atoms, halogenated alkoxy, halogenated alkenyl or alkenyloxy, L ¹ and L ² Are independently of each other hydrogen or halogen.

Nematic liquid crystals having a negative dielectric anisotropy of a halogen-based tricyclic structure may be represented by Chemical Formulas 3 to 6.

Formula 3

Formula 4

Formula 5

Formula 6

In Formulas 3 to 6, R, L ¹ , and L ² are as defined in

Formulas

1 and 2, L ³ and L ⁴ are independently hydrogen or halogen, and Z is a single bond, -CF ₂ O-, -OCF _2- , -COO-, -O-CO-, -CH ₂ CH _2- , -CH = CH-, -C≡C-, -CH ₂ O-,-(CH ₂ ) ₄ -, CF = CF-, -CH = CF- or -CF = CH-.

Nematic liquid crystals having a negative dielectric anisotropy of a halogen-based tetracyclic structure may be represented by Chemical Formulas 7 to 9.

Formula 7

Formula 8

Formula 9

In formulas 7 to 9, Y represents hydrogen or halogen, R ¹ represents alkyl having 1 to 15 carbon atoms, or alkenyl, and R ² represents 1 to 15 carbons Alkyl, alkenyl, or alkoxy having atoms (in R ¹ , and R ² , hydrogen may be replaced by CN, CF ₃ , or halogen atoms) , CH ₂ group may be substituted by -O-, -S-, -C≡C-, -CH = CH-, -OC-O- or -O-CO-), Z is a single bond, -CF ₂ O-, -OCF _2- , -COO-, -O-CO-, -CH ₂ CH _2- , -CH = CH-, -C≡C-, -CH ₂ O-,-(CH ₂ ) ₄ -, CF = CF-, -CH = CF- or -CF = CH-.

The nematic liquid crystal having halogen negative dielectric anisotropy has a lateral fluorinated indane derivative and may be represented by the following Chemical Formula 10.

Formula 10

Wherein m represents an integer and n is 0 or 1.

The nematic liquid crystal having cyanide negative dielectric anisotropy may be represented by the following Chemical Formulas 11 to 13.

Formula 11

Formula 12

Formula 13

In Formulas 11-13, R ³ is an alkyl group having 1 to 15 carbon atoms, wherein hydrogen may be unsubstituted or at least monosubstituted by CN, CF _3, or halogen, and CH ₂ groups can be replaced by -O-, -S-, -C≡C-, -CH = CH-, -OC-O- or -O-CO-) and L ¹ and L ² independently of each other Hydrogen or halogen, Z is a single bond, -CF ₂ O-, -OCF _2- , -COO-, -O-CO-, -CH ₂ CH _2- , -CH = CH-, -C≡ C-, -CH ₂ O-,-(CH ₂ ) _4- , CF = CF-, -CH = CF- or -CF = CH-.

The negative liquid crystal having dielectric anisotropy may be a single substance or a mixture. According to an embodiment, the nematic liquid crystal mixture having negative dielectric anisotropy,

(a) Liquid Crystal Component A consisting of at least one compound having a dielectric anisotropy of less than -1.5:

(b) a liquid crystal component B consisting of at least one compound having a dielectric anisotropy of -1.5 to +1.5: and

(c) chiral component C may be included.

The liquid crystal component A may include one or more compounds of Formulas 14 to 17.

Formula 14

Formula 15

Formula 16

Formula 17

The liquid crystal component B may include one or more compounds of Formulas 18 to 20. The liquid crystal component B may be the first base liquid crystal molecules described above.

Formula 18

Formula 19

Formula 20

In Formulas 18 to 20, R ⁴ and R ⁵ are each independently alkyl, alkoxy, alkoxy alkyl, alkenyl, or alkenyloxy having 1 to 15 carbon atoms. oxy) and wherein hydrogen may be substituted by CN, CF ₃ , or halogen atoms, and the —CH ₂ — group is —CH═CH—, —O—, —CO—, —COO— , -OOC-, -O-OC-O- or -S-), Y ¹ represents hydrogen or halogen.

Chiral component C is available in a number of chiral dopants, such as in the examples below. The choice of chiral dopant is not important by itself.

Nematic liquid crystals with positive dielectric anisotropy

According to an embodiment, the nematic liquid crystal having positive dielectric anisotropy may include nematic liquid crystal molecules having positive dielectric anisotropy. In one aspect, the nematic liquid crystal molecules having the positive dielectric anisotropy may be a single type. In another aspect, the nematic liquid crystal molecules having the positive dielectric anisotropy may be of different kinds from each other. For example, the nematic liquid crystal molecules having the positive dielectric anisotropy may include liquid crystal molecules having the first dielectric anisotropy and liquid crystal molecules having the second dielectric anisotropy. In this case, the second dielectric anisotropy may be different from the first dielectric anisotropy. At least one of the first dielectric anisotropy and the second dielectric anisotropy may have dielectric anisotropy having positive anisotropy. The overall dielectric anisotropy of the nematic liquid crystal molecules including the liquid crystal molecules having the first dielectric anisotropy and the liquid crystal molecules having the second dielectric anisotropy is sufficient to have a positive dielectric property.

According to another embodiment, the nematic liquid crystal having positive dielectric anisotropy may include nematic liquid crystal molecules and base liquid crystal molecules having positive dielectric anisotropy. Each of the base liquid crystal molecules may include at least one selected from the group consisting of liquid crystal molecules having negative dielectric anisotropy, liquid crystal molecules having positive dielectric anisotropy, neutral liquid crystal molecules, chiral liquid crystal molecules, and non-chiral liquid crystal molecules. Can be. In one aspect, the nematic liquid crystal having a positive dielectric anisotropy may include nematic liquid crystal molecules having a kind of dielectric anisotropy and base molecules. In another aspect, the nematic liquid crystal having positive dielectric anisotropy may include liquid crystal molecules having various kinds of dielectric anisotropy, and base liquid crystal molecules.

Hereinafter, nematic liquid crystals having positive dielectric anisotropy will be described by listing examples. The following materials may be used alone or in combination.

The nematic liquid crystal having a positive dielectric anisotropy may include a nematic liquid crystal having a positive dielectric anisotropy of a cyanide group, an isocyanate group, and a halogen group. The nematic liquid crystal having the positive dielectric anisotropy may be used singly or in combination with the cyanide group, the isocyanate group, and the halogen-based nematic liquid crystal having the positive dielectric anisotropy. In addition, the nematic liquid crystal having the positive dielectric anisotropy may further include second base liquid crystal molecules.

The nematic liquid crystal having positive dielectric anisotropy may have a bicyclic structure or a tricyclic structure.

The cyanated nematic liquid crystal of the bicyclic structure may be represented by Chemical Formula 21.

Formula 21

R ⁶ in Formula 21 is alkenyl having 1 to 15 carbon atoms. Wherein hydrogen may be substituted by CN, CF ₃ , or halogen, and the —CH ₂ — group is —CH═CH—, —O—, —CO—, —COO—, —OOC— , Which may be optionally substituted by -O-OC-O- or -S-.

In formula 21, R ⁷ is H, CH ₃ , C ₂ H ₅ or nC ₃ H ₇ .

The nematic liquid crystal having positive dielectric anisotropy of the tricyclic structure may be represented by Chemical Formula 22.

Formula 22

R ³ is as R ³ is unsubstituted or CN, CF _3, or halogen-alkyl (alkyl) having at least one carbon atom less than the 15-substituted one by (halogen) groups as defined in Formula 11 to 13, wherein One or more CH ₂ groups in these alkyls may be replaced by —O—, —S—, —C≡C—, —CH═CH—, —OC—O— or —O—CO—, L ¹ and L ² each independently is hydrogen or halogen (halogen) with each other.

Nematic liquid crystals having an isocyanate-based dielectric anisotropy can be represented by the following formula (23).

Formula 23

In Formula 23, R ⁸ is C _n H _{2n + 1} O, C _n H _{2n + 1} , or C _n H2 _n-1 , wherein n is 1 to 15 and A is

or

, B is -CH ₂ -CH ₂ -or -C≡C-, X ¹ is hydrogen or halogen, m is 1 2,3, or 4. Specific examples of Formula 23 are shown next.

Nematic liquid crystals having a halogen-based positive dielectric anisotropy may include a fluorine-based or chlorine-based material and may have a single or polycyclic structure. Nematic liquid crystals having fluorine-based dielectric anisotropy may be represented by Chemical Formulas 24 to 27.

Formula 24

Formula 25

Formula 26

Formula 27

In Formulas 24 to 27, R ⁹ and R ¹⁰ are alkyl, alkoxy, fluorinated alkyl, fluorinated alkoxy, alkenyl having 1 to 15 carbon atoms. ), Alkenyloxy, alkoxy alkyl or fluorinated alkenyl, L ²¹ L ²² L ²³ , and L ²⁴ are each independently hydrogen or fluorine, Z Is a single bond, -CF ₂ O-, -OCF _2- , -COO-, -O-CO-, -CH ₂ CH _2- , -CH = CH-, -C≡C-, -CH ₂ O-, -(CH ₂ ) _4- , CF = CF-, -CH = CF- or -CF = CH-.

The nematic liquid crystal having positive dielectric anisotropy of the halogen series bicyclic structure may be represented by the following Chemical Formula 28.

Formula 28

In Formula 28, R ¹¹ represents hydrogen, halogen, alkenyl having 1 to 15 carbon atoms, alkenyloxy, alkynyl, or alkynoxy, wherein R One or more -CH ₂ -groups at ¹¹ may be substituted with —O—, C═O or —S—, L ⁵ is halogen, fluorinated alkyl having 1 to 15 carbon atoms, alkoxy (fluorinated alkoxy), Fluorinated alkenyl, alkenyloxy or oxyalkyl, -OCF ₃ , -OCHFCF ₃ or SF ₅ , and L ⁶ , L ⁷ , L ⁸ , and L ⁹ are each independent of each other Is hydrogen (H) or halogen, Z is a single bond, -CF ₂ O-, -OCF _2- , -COO-, -O-CO-, -CH ₂ CH _2- , -CH = CH- , -C≡C-, -CH ₂ O-,-(CH ₂ ) _4- , CF = CF-, -CH = CF- or -CF = CH-. Specific examples of Formula 28 are shown next.

Wherein n is 1 to 15.

The nematic liquid crystal having positive dielectric anisotropy of the halogen-based tricyclic structure may be represented by Chemical Formulas 29 to 33.

Formula 29

Formula 30

Formula 31

Formula 32

Formula 33

In formulas 29 to 33, R ¹² is alkyl or alkenyl having 1 to 15 carbon atoms (wherein alkyl or alkenyl is unsubstituted or at least monosubstituted by CN, CF ₃ , or halogen) And one or more -CH ₂ -groups may be substituted by -O-), X ³ is -F, -Cl, -OCF ₃ , -OCHF ₂ , -OCH ₂ F or -CF ₃ . Specific examples of the formula (29) are as follows.

Here, R ¹² is as defined above.

The nematic liquid crystal having positive dielectric anisotropy of the halogen-based tetracyclic structure may be represented by Chemical Formulas 34 to 36.

Formula 34

Formula 35

Formula 36

R ¹³ in Formulas 34 to 36 are each alkyl, alkoxy or alkenyl having 1 to 15 carbon atoms (in the alkyl, alkoxy, or alkenyl, hydrogen is CN, CF ₃ , or halogen ( halogen), and the -CH ₂ -group may be substituted with -CH = CH-, -O-, -CO-, -COO-, -OOC-, -O-OC-O- or -S-. Z is a single bond, -CF ₂ O-, -OCF _2- , -COO-, -O-CO-, -CH ₂ CH _2- , -CH = CH-, -C≡C-,- CH ₂ O—, — (CH ₂ ) ₄ —, CF═CF—, —CH═CF— or —CF═CH—.

A nematic liquid crystal having a positive dielectric anisotropy containing a trisubstituted fluorine or cyanide group may be represented by the formula (37).

Formula 37

In formula 37, at least one of two R ¹⁴ and R ¹⁵ is an alkenyl group having up to 15 carbon atoms unsubstituted or at least monosubstituted by CN, CF ₃ or halogen, and the other One can be an alkyl group having up to 15 carbon atoms unsubstituted or at least monosubstituted by halogen, CN, CF ₃ or halogen, wherein one or more CH ₂ groups of these groups are -O-, -S May be replaced by-, -C≡C-, -OCO-, or -O-CO-. Specific examples of Formula 37 are shown next.

n and m are 1 to 10, preferably 1 to 5, o and p are each independently the same or different and are 0 to 10, preferably 0 to 5, provided that the sum of o + p is preferably Is 7 or less.

The nematic liquid crystals having said positive dielectric anisotropy can be a single substance or a mixture. Nematic liquid crystal mixture having a positive dielectric anisotropy according to one embodiment,

a) liquid crystal component A consisting of one or more compounds having a dielectric anisotropy greater than +1.5,

b) a liquid crystal component consisting of one or more compounds having a dielectric anisotropy of -1.5 to +1.5, and

c) including chiral component C, if necessary;

Liquid crystal component A may include one or more compounds of Formula 37. Liquid crystal component B may include one or more compounds represented by Formula 38 below. The liquid crystal component B may be the second base liquid crystal molecules described above.

Component C is cholesteryl nonanoate (CN), R-811, S-811, S-1011, S-2011 (Merck KGaA, Darmstadt, Germany) with a number of chiral dopants; Many chiral dopants on the market are available, such as CB15 (BDH, Poole, UK). The choice of dopant is not important by itself.

Formula 38

R ¹⁶ and R ¹⁷ are each independently the same or different and each is an alkyl group having up to 15 carbon atoms which are unsubstituted or at least monosubstituted by CN, CF _3, or halogen, Wherein one or more CH ₂ in these alkyl groups may be replaced by —O—, —S—, —C≡C—, —CH═CH—, —OC—O— or —OCO—, wherein 1,4- The phenylene (1,4-phenylene) ring may be mono- or polysubstituted by fluorine independently of each other.

B-chiral smectic liquid crystal

Smectic liquid crystals are found at lower temperatures than nematic liquid crystals, and rod-shaped liquid crystals form a layered structure so that the liquid crystals are arranged in parallel with each other. In the plane of the layer, there is no regularity in the position of the liquid crystal, but the positional order of the liquid crystal position is maintained in the direction perpendicular to the plane. The bonds between the molecular layers are relatively weak and have a slippery property. Because of this, smectic liquid crystals exhibit the properties of two-dimensional fluids. However, the viscosity is very high compared to ordinary liquids.

The non-chiral smectic liquid crystal may have various structures depending on the liquid crystal arrangement. In one example, Smectic A liquid crystal is arranged perpendicular to the molecular plane (plane). In another example, the Smectic C liquid crystal is arranged at an angle with the molecular layer. In another example, Smectic B is arranged perpendicular to the molecular layer but the liquid crystals are arranged in a hexagonal network within the layer. The types of smectic liquid crystals are various, and the types of smectic liquid crystals in the present invention are not limited to those described above.

According to one embodiment, the non-chiral smectic liquid crystal may include non-chiral smectic liquid crystal molecules. In one aspect, the non-chiral smectic liquid crystal molecules may be a single type. In another aspect, the non-chiral smectic liquid crystal molecules may be of different types from each other. For example, the non-chiral smectic liquid crystal molecules may include a first non-chiral smectic liquid crystal molecule and a second non-chiral smectic liquid crystal molecule. In this case, the second non-chiral smectic liquid crystal molecule may be different from the first non-chiral smectic liquid crystal molecule.

According to another embodiment, the non-chiral smectic liquid crystal may include non-chiral smectic liquid crystal molecules and base liquid crystal molecules. Each of the base liquid crystal molecules may include at least one selected from the group consisting of liquid crystal molecules having negative dielectric anisotropy, liquid crystal molecules having positive dielectric anisotropy, and neutral liquid crystal molecules. In one aspect, the non-chiral smectic liquid crystal may include one kind of non-chiral smectic liquid crystal molecules and base molecules. In another aspect, the non-chiral smectic liquid crystal may include different non-chiral smectic liquid crystal molecules and base molecules.

Hereinafter, the non-chiral smectic liquid crystal will be described by listing examples. The following materials may be used alone or in combination. The non-chiral smectic liquid crystal may include a smectic A liquid crystal, a smectic B liquid crystal, a smectic C liquid crystal, and the like.

Smectic A liquid crystal may be represented by the following formula 39 to 41.

Formula 39

Formula 40

Here, 1≤n≤15.

Formula 41

Here, Ph is a 1, 4-phenylene group.

The smectic B liquid crystal may comprise 4-hexyl-4 '-[2- (4-isothiocyanatophenyl) ethyl] -1-1'-biphenyl, between 60.3 and 98.5 ° C. In addition, the smectic B liquid crystal is 1- [5- (4-hexylphenyl) pyramidyl-2] -2- (4-hexyloxyphenyl) ethane, PhPhCHNPhCHCHCOOCH ₂ CH (CH ₃ ) ₂ , C ₆ H ₁₃ OPhCHNPhPh, C ₈ H ₁₇ OPhPhCOOPhOC ₅ H ₉ , C ₈ H ₁₇ PhPhCOOPhC ₈ H ₁₇ , C ₈ H ₁₇ OPhPhCOOPhOC ₇ H ₁₇ , C ₅ H _{11 It} may comprise at least one selected from the group consisting of OPhCHNPhPh and C ₁₆ H ₃₃ OPhCHNPhPh.

Smectic C liquid crystal may be represented by the following Chemical Formulas 42 to 44.

Formula 42

Here, each of A and B is a benzene ring or a cyclo nucleic acid ring, m and n are 0 or 1, and each of R ₁ and R ₂ is an alkyl group, an alkoxy group or an alkanoyloxy group having 1 to 18 carbons.

Formula 43

Here, each of R ₃ and R ₄ is an alkyl group having 1 to 18 carbons.

Formula 44

Wherein X is cobalt bond or -O-, n is 0 to 10, R ₅ is an alkyl group or alkoxy group having 1 to 18 carbons, and R ₆ is an alkyl group having 2 to 18 carbons.

According to the present embodiment, since the liquid crystal layer includes a nematic liquid crystal and a non-chiral smectic liquid crystal, the alignment of the liquid crystal layer may be uniform and the stability of the alignment may be improved.

According to another embodiment of the present invention, the liquid crystal layer may further include a chiral liquid crystal. The liquid crystal layer may include a chiral liquid crystal, a non-chiral smectic liquid crystal, and a nematic liquid crystal. In the liquid crystal layer, the total amount of the chiral liquid crystal and the non-chiral smectic liquid crystal may account for about 1 wt% to about 50 wt%. For example, the chiral liquid crystal may occupy about 0.01 wt% to 10 wt% in the liquid crystal layer.

According to one aspect, the chiral liquid crystal may include chiral liquid crystal molecules. For example, the chiral liquid crystal molecules may be one kind. As another example, the chiral liquid crystal molecules may be of different types. For example, the chiral liquid crystal molecules may include chiral liquid crystal molecules having spontaneous polarization and chiral liquid crystal molecules having no spontaneous polarization. In addition, the chiral liquid crystal molecules may include chiral liquid crystal molecules having different spontaneous polarization characteristics.

According to another aspect, the chiral liquid crystal may function as a ferroelectric material together with the non-chiral smectic liquid crystal. Although ferroelectric liquid crystals have spontaneous polarization even when an electric field is not applied, it is a kind of dielectric that is an electrically insulator, but unlike general dielectrics, dielectric polarization is not proportional to electric field, and the relationship between polarization and electric field It has the characteristic which shows the ideal with electric history. Ferroelectric liquid crystals have not only spontaneous polarization, but also physical properties in which spontaneous polarization is reversed by an electric field.

Hereinafter, examples of the chiral liquid crystals will be listed and described. In the present invention, the chiral liquid crystal is not limited to the following materials.

The chiral liquid crystal may be a fluorine chiral end liquid crystal, a chiral allyl ester liquid crystal, a center core polyring chiral liquid crystal, or a chiral smectic. Liquid crystal and the like. In addition, the chiral liquid crystal may be a banana shape liquid crystal.

Fluorine-based chiral terminal liquid crystal may be represented by the formula (45).

Formula 45

Wherein X ⁴ , X ⁵ , X ⁶ and X ⁷ are each independently CF ₃ , CF ₂ H _, CFH ₂ , halogen, alkyl or alkoxy, and C and D are independently Phenyl, mono-fluorophenyl, di-fluorophenyl, or cyclo-hexyl, E is independently a single bond, COO, OOC, and C≡C Is selected from at least one of E is a single bond, q is 0 or 1, and R ¹⁸ is a terminal group of the formula (40).

Formula 46

In formula 46, Z is O, (CH ₂ ) ₁ O, or (CH ₂ ) ₂ O, J and M are independently selected from hydrogen, alkyl of 1 to 15 carbon atoms, W is a carbon atom 1 to 15 straight or branched alkyl chains, each of J, M and W different, and R ¹⁹ represents alkenyl, alkenyloxy, alkynyl containing from 1 to 15 carbon atoms ), Or alkynoxy.

The chiral aryl ester liquid crystal may be represented by Formula 47.

Formula 47

In Formula 47, R _a and R _b are each independently alkyl having 1 to 20 carbon atoms, Q is -C (= 0) O- or -OC (= 0), and Z is fluorine ) Represents an alkyl group substituted with alkyl or halogen, and * represents chiral carbon. Specific examples of formula 41 include 4'-n- (octyloxyphenyl4 '-(1,1,1-trifluoro-2-octyloxycarbonyl) biphenyl-4-carboxylate (4) '-n- (octyleoxyphenyl4'-(1,1,1-trigluoro-2-octyloxycarbonyl) biphenyl-4-carboxylate).

The central core polyring chiral liquid crystal may be represented by Chemical Formulas 48 to 51.

Formula 48

Formula 48 is S-4- (trans-4-heptylcyclohexyl) -3'-chloro-4 "-(1-methylheptyloxy) terphenyl (S-4- (trans-4-heptylcyclohexyl) -3'- chloro-4 "-(1-methylheptyloxy) terphenyl).

Formula 49

Formula 49 is R-4-octyl-3 "-chloro-4 '' '-(1-methylhexyloxy) quaterphenyl (R-4-octhyl-3" -chloro-4' ''-(1-methylhexyloxy ) quarterphenyl).

Formula 50

Chemical Formula 50 is S-4-nonyl-3'-fluoro-4 '' '-(2-chloropropyloxy) quaterphenyl (S-4-nonyl-3'-fluoro-4' ''-(2-chloropropyloxy ) quarterphenyl).

Formula 51

Formula 51 is butyl S-2- (4-octyl-2'-fluoro-3 "-trifluoromethyl-4 '' '-quaterphenyloxy) -propionate (S-2- (4-octyl- 2'-fluoro-3 "-trifluoromethyl-4 '' '-quarterphenyloxy) -propionate).

The chiral liquid crystal may be represented by at least one of Chemical Formulas 52 and 53.

Formula 52

Formula 53

In formulas 52 and 53, R ²⁰ and R ²¹ each represent a linear alkyl group having 1 to 9 carbon atoms, and R ²² and R ²³ each represent the same or different linear alkyl group having 1 to 18 carbon atoms ( In R ²⁰ to R ²³ , hydrogen may be substituted by CN, CF ₃ , or halogen atom, and —CH ₂ — group is —CH═CH—, —O—, —CO—, —COO— , -OOC-, -O-OC-O- or -S-), and X represents hydrogen or halogen. Specific examples of Formulas 52 and 53 are shown next.

The chiral smectic liquid crystal may be represented by Chemical Formula 54.

Formula 54

In formula 54, R ²⁴ is a chiral or achiral alkyl or alkenyl having 1 to 20 carbon atoms, R ²⁵ is a chiral or achiral alkoxy having 1 to 20 carbon atoms (alkoxy), alkenyloxy, alkylcarbonyloxy (alkyl-COO-) or alkenylcarbonyloxy (alkenyl-COO-) (in R ²⁴ and R ²⁵ , hydrogen is CN , CF ₃ , or halogen atom, and -CH ₂ -group is -CH = CH-, -O-, -CO-, -COO-, -OOC-, -O-OC- Z ¹ is a single bond, -COO- or -OOC-, -CH ₂ CH _2- , -CH = CH-, -C≡C-, -OCH ₂ -Or -CH ₂ O-, L ¹⁰ to L ¹⁴ is hydrogen, halogen, cyano, nitro, alkyl or alkenyl of 1 to 20 carbon atoms )-(CH ₂ -group can be substituted by -CH = CH-, -O-, -CO-, -COO-, -OOC-, -O-OC-O- or -S-) X ⁹ is -CH- or Soyida. Specific examples of Formula 54 are shown below.

Banana type chiral liquid crystal may be represented by the formula (55).

Formula 55

In Formula 55, A ¹ is

or

And B1 is

or

R ²⁶ and R ²⁷ are each independently hydrogen or halogen, and R ²⁸ and R ²⁹ are independently alkyl or alkoxy having 8 to 16 carbon atoms. Specific examples of Formula 49 are shown below.

The chiral liquid crystal may be a single material of the chiral liquid crystal or a mixture including the chiral liquid crystal.

Formula 56

In formula 56, X ¹⁰ is hydrogen (H), R ³⁰ is hydrogen or alkyl of 1 to 15 carbon atoms, R ³¹ is hydrogen, halogen, alkyl group of 1 to 20 carbon atoms or Alkenyl groups, where in each case one or two -CH ₂ -groups may be replaced by -O-, -C (= 0) O- or -Si (CH ₃ ) _2- At least one hydrogen of the alkyl, alkenyl group may be replaced by fluorine or CH ₃ ), and R ³² , R ³³ , R ³⁴ , and R ³⁵ are each CH ₃ .

According to the present embodiment, since the liquid crystal layer includes a nematic liquid crystal and a non-chiral smectic liquid crystal, the alignment of the liquid crystal layer may be uniform and the stability of the alignment may be improved. In addition, when the liquid crystal layer contains a chiral liquid crystal, ferroelectric characteristics can be expressed together with the non-chiral smectic liquid crystal, so that the alignment of the liquid crystal layer can be made more uniform and the stability of the alignment can be further improved.

According to another embodiment of the present invention, the liquid crystal layer may further include a reactive mesogen material. The liquid crystal layer may include about 0.01% to about 3% by weight reactive mesogen material, about 1% to about 50% by weight of a non-chiral smectic liquid crystal and an extra nematic liquid crystal.

The reactive mesogenic material means a polymerizable mesogenic compound. A "mesogenic compound" or "mesogenic material" may include a substance or compound comprising one or more rod-shaped, plate- or disc-shaped mesogenic groups, ie groups having the ability to induce liquid crystalline behavior. The reactive mesogen material may be a material which is polymerized by light such as ultraviolet rays and is oriented according to the alignment state of adjacent materials.

Examples of the reactive mesogen material include compounds represented by the following formula:

P1-A1- (Z1-A2) n-P2,

Wherein P1 and P2 are at least one of acrylate, methacrylate, vinyl, vinyloxy and epoxy groups, and A1 and A2 are 1,4-phenylene (phenylen) and naphthalene (naphthalene) -2,6-diyl group is at least one, Z1 is one of COO-, OCO- and a single bond, n may be one of 0, 1 and 2.

More specifically, there may be mentioned a compound represented by one of the following formulas:

Here, P1 and P2 may include at least one of acrylate, methacrylate, vinyl, vinyloxy, and epoxy groups.

According to the present embodiment, since the liquid crystal layer includes a nematic liquid crystal and a non-chiral smectic liquid crystal, the alignment of the liquid crystal layer may be uniform and the stability of the alignment may be improved. In addition, since the liquid crystal layer includes a reactive mesogen material, the alignment speed of the liquid crystal layer may be increased, and the angle at which the liquid crystal layer is aligned may be increased, thereby improving optical characteristics.

According to another embodiment of the present invention, the liquid crystal layer may include a non-chiral liquid crystal, a nematic liquid crystal, a chiral liquid crystal and a reactive mesogen material. In the liquid crystal layer, the total amount of the non-chiral smectic liquid crystal and the chiral liquid crystal may account for about 1% by weight to about 50% by weight. The chiral liquid crystal of the liquid crystal layer may occupy about 0.01% by weight to 10% by weight. The reactive mesogen material may comprise about 0.01 wt% to about 3 wt% of the liquid crystal layer.

See above for details of the non-chiral liquid crystal, nematic liquid crystal, chiral liquid crystal and reactive mesogen material.

According to the present embodiment, the liquid crystal layer includes the non-chiral liquid crystal, the nematic liquid crystal, and the chiral liquid crystal, so that the alignment of the liquid crystal layer can be uniform and the stability of the alignment can be improved. In addition, since the liquid crystal layer includes a reactive mesogen material, the alignment speed of the liquid crystal layer may be increased, and the angle at which the liquid crystal layer is aligned may be increased, thereby improving optical characteristics.

(액정층_제2 실시예)(Liquid Crystal Layer _ Second Embodiment)

The liquid crystal layer according to the embodiments of the present invention may include a nematic liquid crystal and a smectic liquid crystal. The liquid crystal layer may include about 50 wt% to about 97 wt% nematic liquid crystal, and about 3 wt% to about 50 wt% smectic liquid crystal. When the smectic liquid crystal is less than about 3% by weight of the liquid crystal layer, the liquid crystal alignment of the liquid crystal layer may be unstable. In addition, when the smectic liquid crystal exceeds about 50% by weight of the total amount of the liquid crystal layer, the viscosity of the liquid crystal layer may increase, thereby slowing the response speed of the display device including the liquid crystal layer. More preferably, the liquid crystal layer may include about 3% by weight to about 35% by weight smectic liquid crystal.

The amount of smectic liquid crystal in the liquid crystal layer may be determined by the viscosity of the smectic liquid crystal. When the viscosity of the smectic liquid crystal is low, the smectic liquid crystal in the liquid crystal layer may include about 50% by weight or more. On the other hand, when the viscosity of the smectic liquid crystal is high, in consideration of the overall viscosity of the liquid crystal layer, it may be desirable to maintain at about 30% by weight or less.

According to an embodiment of the present invention, the smectic liquid crystal may include a non-chiral smectic liquid crystal and a chiral smectic liquid crystal. The smectic liquid crystal may include about 70 wt% to about 97 wt% non-chiral smectic liquid crystal and about 3 wt% to about 30 wt% chiral smectic liquid crystal.

The chiral smectic liquid crystal may have a spontaneous polarization characteristic. Spontaneous polarization refers to a phenomenon in which a material is electrically polarized in a natural state without an electric field applied. The chiral smectic liquid crystal will be described later in detail.

According to an embodiment, the nematic liquid crystal may include a nematic liquid crystal having negative dielectric anisotropy. According to another embodiment, the nematic liquid crystal may include a nematic liquid crystal having negative anisotropy and a nematic liquid crystal having positive dielectric anisotropy. The nematic liquid crystal having the positive dielectric anisotropy may occupy about 10% by weight of the nematic liquid crystal.

The components, structures, and examples of the non-chiral smectic liquid crystals of the nematic liquid crystal and the smectic liquid crystal described in this embodiment are substantially the same as those described above, and thus the detailed description thereof will be omitted.

Hereinafter, the chiral smectic liquid crystal will be described in more detail.

The chiral smectic liquid crystal may include chiral smectic liquid crystal molecules. According to one aspect, chiral smectic liquid crystal molecules may be one kind. In another aspect, the chiral smectic liquid crystals may be of different types from each other. For example, chiral smectic liquid crystal molecules may include a first chiral smectic liquid crystal molecule and a second chiral smectic liquid crystal molecule. The first and second chiral smectic liquid crystal molecules may be different from each other.

According to another embodiment, the chiral smectic liquid crystal may include chiral smectic liquid crystal molecules and base liquid crystal molecules. The base liquid crystal molecules may include at least one selected from the group consisting of liquid crystal molecules having negative dielectric anisotropy, liquid crystal molecules having positive dielectric anisotropy, neutral liquid crystal molecules, and non-chiral liquid crystal molecules.

According to another embodiment, the chiral smectic liquid crystal may cause the liquid crystal layer to exhibit ferroelectric characteristics together with the non-chiral liquid crystal molecules.

Chiral smectic liquid crystals include chiral smectic C liquid crystals and other chiral smectic liquid crystals.

Chiral Smectic C may be represented by Formula 57 to Formula 60.

Formula 57

or

Formula 58

In formula (57) and formula (58), R is an alkyl group having 1 to 10 carbons, or

Is a group, R 'is an alkyl group having from 1 to 4 carbons, and T is

or

X is an alkyl or halogen substituted alkyl group having at least one chiral center, Y is a fluorine atom, m has 0, 1 or 2, p has 2, 3 or 4, n is 10, Has 11 or 12.

Formula 59

In formula 59, R ¹ and R ² are linear alkyl groups containing 1 to 9 carbons and are different from each other.

Formula 60

In formula 60, R ³ and R ⁴ are alkyl groups containing 1 to 18 carbons, the same or different from each other, and X is hydrogen or fluorine.

Formula 61

In formula 61, l is 1 or 2, and Y is —COO—, —CH═N—, —CH ₂ O—, —OCO—, —N═CH—, —OCH 2 — or a single link, R ¹⁰ Is an alkyl or alkoxy group having 1 to 18 valent carbons, R ¹¹ is (S) -2-methylbutyl, (S) -2-methylbutoxy, (S) -2-methylbutoxycarbonyl, (S) -1-methylheptyloxy, (R) -1-methylheptyloxy, (S) -1-methylheptyloxycarbonyl or (R) -1-methylheptyloxycarbonyl.

Formula 62

In formula 62, n is 1 or 2, R is an alkyl or alkoxy group containing 1 to 18 carbons, Y is an alkyl, alkoxy, aloxycarbonyl, alkanoyl or alkanoyloxy group having an asymmetric carbon, X is

Include a group.

In formula 62, Y is

It can be one of the groups.

According to the present embodiment, since the liquid crystal layer includes a nematic liquid crystal, a non-chiral smectic liquid crystal and a chiral smectic liquid crystal, the alignment of the liquid crystal layer may be uniform and the stability of the alignment may be improved.

According to another embodiment of the present invention, the liquid crystal layer may further include a chiral dopant. The chiral dopant may be included in about 10% by weight or less in the liquid crystal layer. According to one aspect, the chiral dopant may have no spontaneous polarization characteristics. According to another aspect, the chiral dopant may have a lower spontaneous polarization characteristic than the chiral smectic liquid crystal.

According to an embodiment, the chiral dopant may include a plurality of chiral dopants. According to one aspect, the chiral dopants may be one kind. According to another aspect, the chiral dopants may be of different types from each other.

According to another embodiment, the chiral dopant may exhibit ferroelectric properties with the smectic liquid crystal.

Hereinafter, examples of the chiral dopant will be listed and described. The following materials may be used alone or in combination. In addition, the chiral dopant in the present invention is not limited to the following materials.

The chiral dopant may be at least one selected from Chemical Formulas 63 to 70.

Formula 63

Formula 64

Formula 65

Formula 66

Formula 67

Formula 68

Formula 69

Formula 70

In formulas 66-70, R ^K is an alkyl group containing 3 to 10 carbons, wherein -CH ₂ -adjacent to the ring in alkyl may be replaced with -O-, and any -CH ₂ -is- Can be replaced by CH-CH-.

Cholesteryl nonanoate (CN), R-811, S-811, S-1011, S-2011 (Merck KGaA, Darmstadt, Germany) with chiral dopants and CB15 (Full, UK) Many chiral dopants, such as BDH), are available.

According to the present embodiment, since the liquid crystal layer includes a nematic liquid crystal, a non-chiral smectic liquid crystal and a chiral smectic liquid crystal, the alignment of the liquid crystal layer may be uniform and the stability of the alignment may be improved. In addition, since the liquid crystal layer further includes a chiral dopant, ferroelectric characteristics can be expressed together with the smectic liquid crystal, thereby making the alignment of the liquid crystal layer more uniform and the stability of the alignment further improved.

According to another embodiment of the present invention, the liquid crystal layer may further include a reactive mesogen material. The liquid crystal layer may include about 0.01 wt% to about 3 wt% of reactive mesogen material. Detailed description of the reactive mesogen material will be omitted.

According to the present embodiment, since the liquid crystal layer includes a nematic liquid crystal, a non-chiral smectic liquid crystal and a chiral smectic liquid crystal, the alignment of the liquid crystal layer may be uniform and the stability of the alignment may be improved. In addition, since the liquid crystal layer includes a reactive mesogen material, the alignment speed of the liquid crystal layer may be increased, and the angle at which the liquid crystal layer is aligned may be increased, thereby improving optical characteristics.

According to another embodiment of the present invention, the liquid crystal layer may include a nematic liquid crystal, a smectic liquid crystal, a chiral dopant and a reactive mesogen material. The liquid crystal layer may include about 3 wt% to about 50 wt% smectic liquid crystal, about 10 wt% or less chiral dopant, and about 0.01 wt% to about 3 wt% reactive mesogen material. Detailed descriptions of the nematic liquid crystal, smectic liquid crystal, chiral dopant and reactive mesogen materials will be omitted.

According to the present embodiment, the liquid crystal layer may include a nematic liquid crystal, a non-chiral smectic liquid crystal, a chiral smectic liquid crystal, and a chiral dopant, thereby making the alignment of the liquid crystal layer uniform and improving stability of the alignment. In addition, since the liquid crystal layer includes a reactive mesogen material, the alignment speed of the liquid crystal layer may be increased, and the angle at which the liquid crystal layer is aligned may be increased, thereby improving optical characteristics.

(액정층의 제조 방법)(Manufacturing Method of Liquid Crystal Layer)

According to an embodiment of the present invention, the liquid crystal layer may be prepared by mixing a nematic liquid crystal and a non-chiral smectic liquid crystal. The liquid crystal layer may be prepared by mixing about 50 wt% to about 99 wt% of nematic liquid crystal and about 1 wt% to about 50 wt% of a non-chiral smectic liquid crystal.

According to one aspect, the liquid crystal layer may further include a chiral liquid crystal. The liquid crystal layer may be prepared by mixing about 10 wt% or less of chiral liquid crystals, about 1 wt% to about 50 wt% of non-chiral smectic liquid crystals, and excess nematic liquid crystals.

According to another aspect, the liquid crystal layer may further include a reactive mesogen material. The liquid crystal layer may be prepared by mixing about 0.01% to about 3% by weight reactive mesogen material, about 1% to about 50% by weight of a non-chiral smectic liquid crystal and an extra nematic liquid crystal. .

According to another aspect, the liquid crystal layer may include a nematic liquid crystal, a non-chiral smectic liquid crystal, a chiral liquid crystal and a reactive mesogen material. The liquid crystal layer comprises about 0.01 wt% to about 3 wt% reactive mesogen material, about 10 wt% or less chiral liquid crystal, about 1 wt% to about 50 wt% non-chiral smectic liquid crystal, and The nematic liquid crystal can be mixed and produced.

According to another embodiment of the present invention, the liquid crystal layer may be prepared by mixing nematic liquid crystal and smectic liquid crystal. The liquid crystal layer may be prepared by mixing about 50 wt% to about 97 wt% nematic liquid crystal and about 3 wt% to about 50 wt% smectic liquid crystal. The smectic liquid crystal may include a non-chiral smectic liquid crystal and a chiral smectic liquid crystal. The smectic liquid crystal may include about 70 wt% to about 97 wt% non-chiral smectic liquid crystal and about 3 wt% to about 30 wt% chiral smectic liquid crystal.

According to one aspect, the liquid crystal layer may further include a chiral dopant. The liquid crystal layer may be prepared by mixing about 10% by weight or less of chiral dopant, about 3% by weight to about 50% by weight smectic liquid crystal and excess nematic liquid crystal.

According to another aspect, the liquid crystal layer may further include a reactive mesogen material. The liquid crystal layer may be prepared by mixing about 0.01 wt% to about 3 wt% reactive mesogen material, about 3 wt% to about 50 wt% smectic liquid crystal, and excess nematic liquid crystal.

According to another aspect, the liquid crystal layer may include nematic liquid crystal, smectic liquid crystal, chiral dopant and reactive mesogen material. The liquid crystal layer comprises less than about 10 wt% chiral dopant, about 0.01 wt% to about 3 wt% reactive mesogen material, about 3 wt% to about 50 wt% smectic liquid crystal and extra nematic liquid crystal. It can be prepared by mixing.

In the mixing process, the process temperature may be a temperature at which the largest amount of material in the liquid crystal layer exhibits isotropic characteristics. According to embodiments of the present invention, the mixing process temperature may be performed in a temperature range of about 90 ° to about 100 °. The temperature range may be a temperature range when the nematic liquid crystal exhibits isotropic characteristics. In the present embodiment, the mixing of the liquid crystal layer is performed within a temperature range of about 90 ° to about 100 °, but the present invention does not limit the mixing temperature of the liquid crystal layer.

Hereinafter, the electrical characteristics of the prepared liquid crystal layer will be described.

4 is a graph showing the electrical characteristics of the liquid crystal layer according to an embodiment of the present invention. The x-axis of FIG. 1 represents time, the unit is seconds, the y-axis represents the applied voltage, and the unit is volts [V].

When a voltage is applied to the liquid crystal layer manufactured by the above-described manufacturing method, as shown in FIG. 4, a peak that is not seen in the liquid crystal layer including only the nematic liquid crystal is shown. This peak is due to the ferroelectric liquid crystal. Therefore, in the liquid crystal layer, the nematic liquid crystal and the ferroelectric liquid crystal are not in the form of a compound but in the form of a mixture, so that the nematic liquid crystal exhibits its own characteristics and the ferroelectric liquid crystal can express its own characteristics. Thus, the nematic liquid crystal and the ferroelectric liquid crystal may enhance and / or interfere with each other.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Example 1. However, the following examples are provided to illustrate the present invention, and the present invention is not limited to the following examples and may be variously modified and changed.

Liquid crystal display

Comparative Example 1

A first display panel comprising a first electrode having a first substrate and a first electrode having a first slit of a Sevron pattern, a second display panel comprising a second electrode having a second substrate and a second slit of a Sevron pattern, and the second display panel; A liquid crystal display device including a liquid crystal layer filling the first and second display panels is manufactured. The liquid crystal display is manufactured in a patterned vertical alignment (PVA) mode.

The liquid crystal layer was prepared by Merck's MLC 6608 (Δn = 0.084, Δε = -4.3) 100% by weight. A cell gap of the liquid crystal layer of the liquid crystal display device was manufactured to 4.5 μm.

A first display panel comprising a first electrode having a first substrate and a first electrode having a first slit of a Sevron pattern, a second display panel comprising a second electrode having a second substrate and a second slit of a Sevron pattern, and the second display panel; A liquid crystal display device including a liquid crystal layer filling the first and second display panels is manufactured. The liquid crystal display device was manufactured in PVA mode.

The liquid crystal layer was prepared as a liquid crystal layer in which 97 wt% of MLC 6608 (Δn = 0.084, Δε = -4.3) of Merck and 3 wt% of KFLC 7 (Δn = 0.18) of Kingston Chemical were mixed at 100 ° C. The thickness of the liquid crystal layer of the said liquid crystal display device was produced in 4.5 micrometers. The 3 wt% KFLC 7 comprises 2.8 wt% non-chiral components and 0.2 wt% chiral components.

The liquid crystal display device of Example 1 was manufactured in the same manner except for the liquid crystal layer material.

The liquid crystal layer was prepared as a liquid crystal layer obtained by mixing 95 wt% of MLC 6608 (Δn = 0.084, Δε = -4.3) of Merck and 5 wt% of KFLC 10 (Δn = 0.18) of Kingston Chemical. The 5 wt% KFLC 10 comprises 4.5 wt% non-chiral component and 0.5 wt% chiral component.

The liquid crystal layer was made of a liquid crystal layer in which 90 wt% of MLC 6608 (Δn = 0.084, Δε = -4.3) of Merck and 10 wt% of KFLC 3 (Δn = 0.18) of Kingston Chemical were mixed at 100 ° C. The 10 wt% KFLC 3 comprises 9.7 wt% of the non-chiral component and 0.3 wt% of the chiral component.

The liquid crystal layer was made of a liquid crystal layer in which 90 wt% of MLC 6608 (Δn = 0.084, Δε = -4.3) of Merck and 10 wt% of KFLC 10 (Δn = 0.18) of Kingston Chemical were mixed at 100 ° C. The 10 wt% KFLC 10 comprises 9.0 wt% of the non-chiral component and 1.0 wt% of the chiral component.

Example 5

The liquid crystal layer was made of a liquid crystal layer obtained by mixing 85 wt% of MLC 6608 (Δn = 0.084, Δε = -4.3) of Merck and 15 wt% of KFLC 5 (Δn = 0.18) of Kingston Chemical. The 15 wt% KFLC 5 comprises 14.3 wt% non-chiral components and 0.7 wt% chiral components.

The liquid crystal layer was made of a liquid crystal layer obtained by mixing 80 wt% of MLC 6608 (Δn = 0.084, Δε = -4.3) of Merck and 20 wt% of KFLC 7 (Δn = 0.18) of Kingston Chemical at 100 ° C. The 20 wt% KFLC 7 comprises 18.6 wt% non-chiral components and 1.6 wt% chiral components.

The liquid crystal layer was made of a liquid crystal layer in which 70 wt% of MLC 6608 (Δn = 0.084, Δε = -4.3) of Merck and 30 wt% of KFLC 3 (Δn = 0.18) of Kingston Chemical were mixed at 100 ° C. The 30 wt% KFLC 3 comprises 29.1 wt% of the non-chiral component and 0.9 wt% of the chiral component.

For Comparative Example 1 and Examples 1 to 7 components and the liquid crystal layer thickness, see Table 1 below.

Table 1

	Nematic liquid crystal	Smectic liquid crystal		Liquid crystal layer thickness
	Nematic liquid crystal	Non-chiral ingredients	Chiral ingredients	Liquid crystal layer thickness
Comparative Example 1	100 wt%	0	0	4.5 ㎛
Example 1	97 wt%	2.8 wt%	0.2 wt%	4.5 ㎛
Example 2	95 wt%	4.5 wt%	0.5 wt%	4.5 ㎛
Example 3	90 wt%	9.7 wt%	0.3 wt%	4.5 ㎛
Example 4	90 wt%	9.0 wt%	1.0 wt%	4.5 ㎛
Example 5	85 wt%	14.3 wt%	0.7 wt%	4.5 ㎛
Example 6	80 wt%	18.6 wt%	1.6 wt%	4.5 ㎛
Example 7	70 wt%	29.1 wt%	0.9 wt%	4.5 ㎛

Permeability Evaluation

5 is a graph comparing the transmittance of the liquid crystal display of Comparative Example 1, Examples 1 to 7. 5 are graphs showing the transmittance according to the applied voltage. The x-axis of FIG. 3 is an applied voltage and a unit is [V], and the y-axis shows transmittance.

Referring to FIG. 5, the transmittance of the liquid crystal display devices of Examples 1 to 7 exhibits excellent overall transmittance as compared to the liquid crystal display device of Comparative Example 1. FIG. In more detail, in Example 1 and Example 2 compared with Comparative Example 1, the effect is insignificant in terms of transmittance, but it can be seen that the transmittance is improved. In addition, the liquid crystal displays of Examples 3 to 7 exhibit a transmittance close to about 0.8, and exhibit excellent transmittances compared to the liquid crystal display of Comparative Example 1 having a transmittance of about 0.6.

From the above evaluation, it is predicted that the non-chiral smectic liquid crystal in the liquid crystal layers of Examples 1 to 7 induces the liquid crystal molecules to be uniformly and stably aligned. Therefore, it can be seen that the transmittance of the liquid crystal display devices of Examples 1 to 7 is superior to that of the liquid crystal display device of Comparative Example 1.

6A is a graph showing the transmittance of the liquid crystal display of Comparative Example 1 and the transmittance according to the amount of non-chiral components in the liquid crystal layer of the liquid crystal display of Examples 1 to 7, and FIG. 6B is the liquid crystal display of Comparative Example 1 Is a graph showing the transmittance of and the transmittance according to the amount of chiral component in the liquid crystal layer of the liquid crystal display of Examples 1 to 7. 6A and 6B, the x axis represents the non-chiral component or the amount of the chiral component, the unit is [% by weight], and the y axis represents the transmittance.

Referring to FIG. 6A, as the non-chiral component in the liquid crystal layer increases, the transmittance of the liquid crystal display devices may be improved. In more detail, Comparative Example 1, that is, when there is no non-chiral component, the transmittance is about 0.67, but it can be seen that as the non-chiral component in the liquid crystal layer increases, the transmittance of the liquid crystal display devices is improved. In addition, when the non-chiral component in the liquid crystal layer is about 9.7 wt% or more, it can be seen that the transmittance is improved to about 0.8.

Referring to FIG. 6B, it can be seen that as the chiral component in the liquid crystal layer increases, the transmittance of the liquid crystal display devices generally improves. In more detail, in Comparative Example 1, that is, when there is no chiral component, the transmittance is about 0.67. However, as the non-chiral component in the liquid crystal layer increases, the transmittance of the liquid crystal display devices is improved. In addition, when the chiral component in the liquid crystal layer is about 0.9% by weight or more, it can be seen that the transmittance is improved to about 0.8.

Response rate evaluation

7 is a graph comparing response speeds of the liquid crystal display of Comparative Example 1 and Examples 1 to 7. FIG. 7 is a graph showing a response speed according to an applied voltage. The x-axis of FIG. 7 is an applied voltage and a unit is [V], and the y-axis is a response speed and a unit is [ms].

Referring to FIG. 7, it can be seen that the response speeds of the liquid crystal display devices of Examples 1 to 7 slightly increased than the response speeds of the liquid crystal display devices of Comparative Example 1. FIG. On the other hand, in Example 7, the response speed of the liquid crystal display including the liquid crystal layer including the non-chiral component of about 29.1 wt% is substantially similar to that of Comparative Example 1. The increased response speed is expected to be lowered by changing the amount or type of nematic liquid crystals. Alternatively, the increased response speed is expected to be lowered by adding more reactive mesogen material to the liquid crystal layer.

FIG. 8 is a graph illustrating the rising time and the polling time of the liquid crystal display of Comparative Example 1 and the rising time and the polling time of the liquid crystal display of Examples 1 to 7 according to the amount of non-chiral component. The x-axis of Figure 8 represents the amount of non-chiral components, the unit is [% by weight], the y-axis represents time and the unit represents [ms].

When the desired transmittance of the liquid crystal display device is 100%, when the liquid crystal display device is turned on, it takes time to display the transmittance 100%. The rising time refers to a time at which 10% to 90% transmittance is exhibited after turning on the liquid crystal display. On the contrary, when the liquid crystal display is turned off, it takes time until the transmittance is 0%. The falling time refers to a time at which 90% to 10% transmittance is exhibited after the liquid crystal display is turned off. Response time is the sum of rising time and polling time.

Comparative Example 1 shows a rising time of about 10 ms and a polling time of about 14 ms, and the response speed was measured to be about 14 ms. Referring to the data of Examples 1 to 7, as the non-chiral component increases, the rising time and the polling time increase, and as a result, the response speed tends to increase slightly.

FIG. 9A is a graph illustrating rising times of the liquid crystal displays of Comparative Examples 1 and 7 and FIG. 9B is a graph illustrating the polling times of the liquid crystal displays of Comparative Examples 1 and 7. 9A and 9B are graphs illustrating rising time and polling time according to an applied voltage. 9A and 9B, the x-axis represents an applied voltage and a unit is [V], and the y-axis represents time and a unit is [ms].

The results of FIGS. 9A and 9B are similar to those described in FIGS. 7 and 8. That is, as compared with Comparative Example 1, the rising time and the polling time of Examples 1 to 7 slightly increased. The increased rise time and polling time are expected to be lowered by adding more reactive mesogen material to the liquid crystal layer.

Texture Evaluation

10A to 10H and 11A to 11H are textures of the liquid crystal display of Comparative Example 1 and Embodiments 1 to 7. FIG.

10A to 10H and 11A to 11H are applied to the liquid crystal display devices of Comparative Examples 1 and 7, and after applying a voltage of 7V, the white polarizer is rotated by rotating the cross polarizer. Black images were obtained.

The textures of FIGS. 10A-10H are white images under a cross polarizer. In more detail, the white images show a case where the angle between the cross polarizer and the liquid crystal molecules of the liquid crystal layer is 45 °, and the light is passed through the liquid crystal layer and is illuminated. This can be confirmed by Equation 1 below.

Equation 1

In Equation 1, T is the transmittance, φ is the angle between the polarizing plate and the liquid crystal molecules, Δn is the birefringence value, d is the thickness of the liquid crystal layer, λ is the wavelength of the light to be irradiated. In the above equation 1, when the value of φ is 45 °, the value of sin ² has the highest value and the highest transmittance.

10A to 10H are textures of Comparative Example 1 and Examples 1 to 7, respectively. Referring to FIG. 8A, a defect that looks black at the edge portions of the slit or the boundary of the slit is shown. 10B to 10H, it can be seen that defects at the boundary of the slit as well as the edge portions of the slit are removed.

The textures of FIGS. 11A-11H are black images under a cross polarizer. In more detail, the black images are a case where the angle between the cross-polarizing plate and the liquid crystal molecules of the liquid crystal layer is 0 °. Show them. In the above formula 1, when the value of φ is 0 °, the value of sin ^{2 has} a value of 0 and the transmittance is zero.

11A to 11H are textures of Comparative Example 1 and Examples 1 to 7, respectively. Referring to FIG. 11A, light leakage is observed at edge portions of the slit or at the boundary of the slit. Referring to FIGS. 11B to 11H, it can be seen that much light leakage is removed from the edge portion and the boundary of the slit, as compared to FIG. 10A.

Looking at the above textures, it can be seen that in the case of the liquid crystal layer containing a smectic material, the alignment of liquid crystal molecules in the liquid crystal layer is uniform and stable compared to the liquid crystal layer containing no ferroelectric material, thereby improving the brightness of the liquid crystal display device. Can be.

12A and 12B are graphs showing gray levels of the textures of Comparative Example 1 and Examples 1 to 7. FIG. 10A and 10B evaluate at 256 (2 ⁸ ) gray levels, show gray closer to black as 0 goes, and show the darkness of gray at a level from 0 to 255. FIG.

FIG. 12A shows the gray level of the texture of FIGS. 10A-10H, which are often seen near 255 of the gray level as white images. Comparative Example 1 of FIG. 10A is seen a lot between gray levels of about 200 to 230, and it can be seen that the width of the peak is wide. Examples 1-7 of FIGS. 10B-10H show much between gray levels of about 235-250, and it can be seen that the peak width is narrower than that of Comparative Example 1. FIG. In addition, it can be seen that as Example 1 goes to Example 7, a lot is seen around the gray level of about 250, and the peak width is also narrowed.

FIG. 12B shows the gray level of the texture of FIGS. 11A-11H, which are often seen near zero of the gray level as black images. In Comparative Example 1 of FIG. 11A, a lot is seen between gray levels of about 30 to 50, and the width of the peak can be seen to be wide. Examples 1-7 of FIGS. 11B-11H show much between gray levels of about 0-25, and it can be seen that the width of the peak is narrower than the peak width of Comparative Example 1. FIG. In addition, it can be seen that as Example 1 goes to Example 7, a lot is seen around the gray level about 0, and the peak width is also narrowed.

Referring to the graphs of FIGS. 12A and 12B, in the case of the liquid crystal layer including the smectic material, the alignment of the liquid crystal molecules in the liquid crystal layer is uniform and stable compared to the liquid crystal layer not containing the ferroelectric material. It can be seen that the improvement.

13A and 13B are graphs showing transmittances according to distances of the textures of Comparative Example 1 and Examples 1 to 7. FIG. 13A and 13B are graphs evaluating transmittances that vary according to distances of slits by cutting textures in one direction.

FIG. 13A illustrates the gray level changed according to the distance of the slit after cutting the textures of FIGS. 10A to 10H in one direction. Referring to FIG. 13A, it can be seen that the transmittance of 20 to 100 around the slits is shown to be blacker than the portion outside the slits. It can be seen that the textures of Examples 1 to 7 have a higher transmittance around the slits than Comparative Example 1.

FIG. 13B illustrates the gray level changed according to the distance of the slit after cutting the textures of FIGS. 11A to 11H in one direction. Referring to FIG. 13B, a light leakage defect is shown by showing a transmittance of 80 to 140 around the slits of Comparative Example 1. Around the slits of Examples 1-7, light leakage defects of 20 to 60 seem to be somewhat resolved.

[[액정 표시 장치 LVA 모드]][[Liquid Crystal Display LVA Mode]]

14A, 15A, and 16A are perspective views illustrating a liquid crystal display according to an exemplary embodiment, and FIGS. 14B, 15B, and 15B illustrate a liquid crystal display according to an exemplary embodiment. 14C, 15C, and 16C are plan views illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

14A to 14C illustrate a case where there is no potential difference between the first and second electrodes of the liquid crystal display. 15A to 15C and 16A to 16C are cases where a potential difference is generated between the first and second electrodes of the liquid crystal display.

14A through 16C, the liquid crystal display includes a first electrode 530, a second electrode 630 spaced apart from the first electrode 530, and the first and second electrodes. The liquid crystal layer 700 may be filled between 530 and 630.

The first electrode 530 and the second electrode 630 may extend in the x-axis direction. According to an embodiment of the present invention, a slit 532 may be formed in the first electrode 530. The slit 532 formed in the first electrode 530 may extend in the y-axis direction. The slit 532 may have a width of several μm. In the present exemplary embodiment, only the first and second electrodes 630 illustrated in FIGS. 14A to 16C will be described by way of example, and the structure of the first and

second electrodes

530 and 630 according to the present invention is described above. It is not limited to a structure.

The liquid crystal layer 700 may include a plurality of liquid crystal molecules 710. Referring to FIG. 14A, the plurality of liquid crystal molecules 710 are perpendicular to a surface of the first or

second electrode

530, 630 when there is no potential difference between the first and

second electrodes

530, 630. May be arranged in a first orientation direction. For example, the first alignment direction may be substantially parallel to the z-axis direction.

When a potential difference occurs between the first and

second electrodes

530 and 630, the orientation of the liquid crystal molecules 710 may be substantially parallel to an extension direction of the first or

second electrodes

530 and 630. It can be changed in the second orientation direction. For example, the second alignment direction may be substantially parallel to the extending direction of the slit 532. As described above, since the slit 532 extends in the y-axis direction, the second alignment direction may be substantially parallel to the y-axis direction.

According to an embodiment of the present invention, when a potential difference occurs between the first and

second electrodes

530 and 630, the liquid crystal molecules 710 may change the alignment directions in at least two steps to finally obtain a second alignment. Can be arranged in a direction. For example, the operation of changing the alignment directions of the liquid crystal molecules 710 may include a first alignment step and a second alignment step that occur sequentially. The reason why the liquid crystal molecules 710 of the liquid crystal layer 700 do not change in a desired direction is due to the structure of the first and

second electrodes

530 and 630. This is because the intensity or shape of the electric field generated between the

electrodes

530 and 630 is different.

Hereinafter, a first alignment step and a second alignment step of sequentially changing the liquid crystal molecules 710 by generating a potential difference between the first and

second electrodes

530 and 630 will be described in detail.

15A to 15C, the first alignment step (as soon as a potential difference occurs between the first and second electrodes) causes the liquid crystal molecules 710 oriented in the first alignment direction to form a third alignment direction. It can be a process of changing to have a. The third alignment direction may include directions different from the first or second alignment direction. The third alignment direction of the liquid crystal molecules 710 may be determined according to the structure of the first and

second electrodes

530 and 630, and the liquid crystal molecules 710 may be formed in the first and second electrodes 530. , 630, may have various orientation directions.

For example, the alignment direction of the liquid crystal molecules 710 in the first alignment step is changed according to the position between the first and

second electrodes

530 and 630. When a potential difference occurs between the first and

second electrodes

530 and 630, the first electrode 530 and the second electrode 530 of the central part (the part farthest from the slit) between the pair of adjacent slits 532 are formed. A relatively strong electric field may be formed between the electrodes 630 perpendicular to the surfaces of the first or

second electrodes

530 and 630. In addition, a relatively weak electric field may be formed in an oblique line between the first electrode 530 and the second electrode 630 of the portion where the slit 532 is formed.

The liquid crystal molecules 710 disposed at the first electrode 530 in the center portion between the pair of adjacent slits 532 where a relatively strong electric field is generated change from the first alignment direction to the third alignment direction. The third orientation direction may be any direction and may not be easy to predict. The liquid crystal molecules 710 disposed on the first electrode 530 having the relatively weak electric field generated slit 532 may be changed from the first alignment direction to the third alignment direction, and the third alignment The direction may be a vertical direction of the electric field. According to one embodiment, the alignment direction of the liquid crystal molecules disposed in one slit of the pair of slits 532 and the alignment direction of the liquid crystal molecules disposed in the other slit may be different from each other. For example, the alignment directions may be directions facing each other.

16A to 16C, the second alignment step (after a predetermined time after the potential difference occurs between the first and second electrodes) may include the liquid crystal molecules 710 aligned in the third alignment direction. May be a process of changing to have the second alignment direction. In detail, the liquid crystal molecules 710 of the central portion of the adjacent pair of slits 532 formed on the first electrode 530 cancel out different orientation directions of the liquid crystal molecules 710 adjacent thereto. Can be changed in the final orientation direction. In this embodiment, the final alignment direction may be a second alignment direction substantially parallel to the direction of the slit 532. When the liquid crystal molecules 710 at the central portion of the pair of slits 532 are changed in the second alignment direction, the unstable arrangement of liquid crystal molecules 710 adjacent to the pair of slits 532 The orientation direction of the liquid crystal molecules 530 of the central portion of the () may be changed in the same orientation direction. As a result, the liquid crystal molecules 710 between the first and

second electrodes

530 and 630 may be changed in a desired second alignment direction.

According to an embodiment of the present invention, the liquid crystal display may include a plurality of pixels. Each of the pixels may include a multi domain. The formation of the multi-domain in one pixel may be determined according to the structure of the first and

second electrodes

530 and 630.

The structures of the first and

second electrodes

530 and 630 of the present invention may vary, and the liquid crystal molecules 710 when a potential difference occurs between the first and

second electrodes

530 and 630. If the first and second alignment steps are sequentially changed as described above, the structure of the first and

second electrodes

530 and 630 is not limited in the present invention.

According to an embodiment, the liquid crystal layer 700 may include a nematic liquid crystal and an achiral smectic liquid crystal. According to another embodiment, the liquid crystal layer 700 may include a nematic liquid crystal and a smectic liquid crystal. The detailed description of the liquid crystal layer 700 is substantially the same as the liquid crystal layer described in the PVA mode, and thus the detailed description thereof will be omitted.

The liquid crystal molecules 710 may have a uniform and stable alignment by nematic liquid crystals and smectic liquid crystals of the liquid crystal layer 700. Therefore, the luminance of the liquid crystal display including the liquid crystal layer 700 may be improved. Experimental evaluation of this will be described in detail through the following experimental example.

According to an embodiment of the present invention, the liquid crystal layer 700 may include a reactive mesogen material. When a potential difference occurs in the first and

second electrodes

530 and 630 due to the reactive mesogen material in the liquid crystal layer 700, the liquid crystal molecules 710 directly align in a second direction in the first alignment direction. Direction can be changed. That is, the liquid crystal molecules 710 may be changed from the first alignment direction to the second alignment direction without changing from the first alignment direction to the third alignment direction, thereby causing a response of the liquid crystal display device. Can improve speed.

According to another embodiment of the present invention, the liquid crystal display includes an alignment layer formed on at least one of the liquid crystal layer 700 and the first electrode 530 and between the liquid crystal layer 700 and the second electrode 630. 540, 640, and FIGS. 17A and 17B) may be further included. The alignment layers 540 and 640 may include a reactive mesogen material. When a potential difference is generated in the first and

second electrodes

530 and 630 by the reactive mesogen material in the alignment layers 540 and 640, the liquid crystal molecules 710 may be aligned in a first alignment direction. Can be changed in the second orientation direction. That is, the liquid crystal molecules 710 may be changed from the first alignment direction to the second alignment direction without changing from the first alignment direction to the third alignment direction, thereby causing a response of the liquid crystal display device. Can improve speed.

17A and 17B are plan views and cross-sectional views for describing a liquid crystal display according to an exemplary embodiment of the present invention. FIG. 17B is a cross-sectional view taken along the line II ′ of FIG. 17A.

17A and 17B, the liquid crystal display includes a first display panel 500, a second display panel 600 spaced apart from and facing the first display panel 500, and the first and second display panels. It may include a liquid crystal layer 700 disposed between (500, 600). In addition, the liquid crystal display may further include a first polarizer 800 and a second polarizer 850 having a transmission axis perpendicular to the transmission axis of the first polarizer 800.

The first display panel 500 may include a first substrate 510, a thin film transistor (TFT), and a first electrode 530. The first substrate 510 may include a transparent insulating material such as glass.

The thin film transistor TFT may be disposed on one surface of the first substrate 510. The thin film transistor TFT may include a gate electrode 512, a gate insulating layer 514, a semiconductor 516, a source electrode 522, and a drain electrode stacked in this order. electrode, 524). The gate electrode 512 may include a single layer or multiple layers of metals or metal alloys, and the gate insulating layer 514 may include silicon oxide, silicon nitride, or silicon oxynitride. The intrinsic semiconductor 516 may include amorphous silicon. The source electrode 522 and the drain electrode 524 may be spaced apart from each other on the intrinsic semiconductor 516. A channel of the thin film transistor TFT may be formed in the intrinsic semiconductor 516 between the source electrode 522 and the drain electrode 524. The source electrode 522 is electrically connected to a data line DL and may receive a data voltage from the data line DL. The drain electrode 524 may be electrically connected to the first electrode 530.

In example embodiments, the thin film transistor TFT may further include ohmic contacts 518 and 520 disposed between the intrinsic semiconductor 516 and the source and drain

electrodes

522 and 524. The ohmic contacts 518 and 520 may include silicide or n ⁺ hydrogenated amorphous silicon doped with a high concentration of n-type impurities.

A first insulating layer 526 having a contact hole 528 may be formed on the thin film transistor TFT. The first insulating layer 526 may include an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or an organic insulating material such as resin. The contact hole 528 may expose an upper surface of the drain electrode 524.

The first electrode 530 may be formed on the first insulating layer 526. The first electrode 530 may be a pixel electrode. The first electrode 530 may be electrically connected to the drain electrode by a contact hole. The first electrode 530 may receive a data voltage from the drain electrode. The first electrode 530 may include a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

According to an embodiment of the present invention, the first electrode 530 may include domain dividing means, for example, a first slit 532. The first slit 532 of the first electrode 530 is a portion from which the first electrode 530 is removed, and a voltage is applied to the first electrode 530 and the second electrode 630. An electric field is generated between the first and

second electrodes

530 and 630, and the electric field is perpendicular to the surface of the first substrate 510 by the first slit 532 of the first electrode 530. Rather than having vertical and horizontal components at the same time, it may be formed to be inclined. In another embodiment of the present invention, the domain dividing means may have a protrusion shape formed on the first electrode 530 and protruding from the first electrode 530 toward the liquid crystal layer 700.

In example embodiments, the first slit 532 may be formed along an edge of the first electrode 530. When the first slit 532 is viewed in plan view, when the first electrode 530 is a quadrangle, the first slit 532 may have a rectangular ring shape. The first slit 532 of the first electrode 530 may have various structures. The structure of the first electrode 530 will be described in detail below.

As described above, the structure of the first electrode 530 is not limited. Along with the second electrode 630 described later, the structure of the first electrode 530 such that the alignment direction of the liquid crystal molecules between the first and

second electrodes

530 and 630 changes in at least two or more steps. It is enough.

The first display panel 500 may further include a first alignment layer 540 between the first electrode 530 and the liquid crystal layer 700. The first alignment layer 540 may pre-tilt the liquid crystal molecules in the liquid crystal layer 700 in one direction. According to an embodiment, the first alignment layer 540 is made of polyamic acid, polyimide, lecithin, nylon, and polyvinylalcohol (PVA). It may include at least one selected from. In another embodiment, the first alignment layer 540 may further include a reactive mesogen material.

The first polarizer 800 may be disposed on the other surface of the first substrate 510. The other surface of the first substrate 510 may be a surface corresponding to the one surface.

The second display panel 600 may include a second substrate 610 and a second electrode 630. The second substrate 610 may include a transparent insulating material such as glass.

The second electrode 630 may be disposed on one surface of the second substrate 610, and one surface of the second substrate 610 may be a surface facing the first display panel 500. The second electrode 630 may be a common electrode. The second electrode 630 may include a transparent conductive material such as ITO or IZO.

According to an embodiment of the present invention, the second electrode 630 may include a domain dividing means, for example, a second slit 632. The second slit 632 may be a portion from which the second electrode 630 is removed to allow the second electrode 630 to have a pattern. When the voltage is applied to the first and

second electrodes

530 and 630, the second slit 632 generates an electric field between the first and

second electrodes

530 and 630. By the two slits 632, the electric field may be formed to be inclined at the same time having vertical and horizontal components instead of perpendicular to the surface of the second substrate 610. According to another embodiment of the present invention, the second electrode 630 may have a protrusion shape protruding from the second electrode 630 toward the liquid crystal layer 700.

In an exemplary embodiment, the second slit 632 may include a first line 632a crossing the center of the second electrode 630 in a first direction and a center of the second electrode 630 in the first direction. It may include a second line 632b crossing in a second direction perpendicular to the direction. The second slit 632 may have a cross shape in plan view. The structure of the second electrode 630 will be described in detail below. According to another aspect, the second electrode 630 may not have the second slit 632 according to the structure of the first electrode 530.

As described above, the structure of the second electrode 630 is not limited. It is sufficient if the structure of the second electrode 630 together with the first electrode 530 allows the orientation direction of the liquid crystal molecules between the first and

second electrodes

530 and 630 to change at least two or more steps. .

According to the embodiments of the present invention, when the voltage is applied by the first and

second slits

532 and 632 of the first and

second electrodes

530 and 630 as described above, the first and second An inclined electric field may be formed between the two

electrodes

530 and 630. As a result, multi-domains D1 to D4 may be formed in one pixel. In the present exemplary embodiment, liquid crystal molecules are arranged in four directions, whereby four domains D1 to D4 may be formed in one pixel. However, in the present invention, it does not limit the number of domains formed in the pixel.

In example embodiments, the second display panel 600 may further include a color filter 612. The color filter 612 may be disposed between the second substrate 610 and the second electrode 630. In addition, a light blocking member 614 may be disposed on one surface of the second substrate 610, and the color filter 612 may be formed in each area defined by the light blocking member 614. The color filter 612 may be protected by the second insulating layer 616. In the present exemplary embodiment, the color filter 612 is described as being disposed on the second display panel 600, but the color filter 612 may be disposed on the first display panel 500. In the present invention, the position of the color filter 612 is not limited.

According to another exemplary embodiment of the present invention, the second display panel 600 may further include a second alignment layer 640 between the second electrode 630 and the liquid crystal layer 700. The second alignment layer 640 may initially align the liquid crystal molecules in the liquid crystal layer 700 in one direction. According to one embodiment, the second alignment layer 640 is made of poly-amic acid, polyimide, lecithin, nylon, polyvinylalcohol (PVA). It may include at least one selected from. According to another embodiment, the second alignment layer 640 may further include a reactive mesogen material.

The second polarizer 850 may be disposed on the other surface of the second substrate 610. The other surface of the second substrate 610 may be a surface corresponding to the one surface. The second polarizer 850 may pass a linear polarization component that vibrates in a vertical direction among the light that has passed through the first polarizer 800.

The liquid crystal layer 700 may fill the gaps between the first and

second display panels

500 and 600. According to an embodiment, the liquid crystal layer 700 may include a negative nematic liquid crytal having a negative dielectric anisotropy, a positive nematic liquid crytal having a positive dielectric anisotropy, and a ferroelectric liquid. crystal). According to another embodiment, the liquid crystal layer 700 may include a non-ferroelectric liquid crystal and a ferroelectric liquid crystal. The description of the liquid crystal layer 700 is substantially the same as that described in the PVA mode, and a detailed description thereof will be omitted. According to another embodiment, the liquid crystal layer may further include a reactive mesogen material. The detailed description of the liquid crystal layer 700 is substantially the same as that described in the PVA mode, and thus the detailed description thereof will be omitted.

According to an embodiment of the present invention, the liquid crystal display may further include an optical compensation film 830. The optical compensation film 830 may be disposed between the second polarizer 850 and the second substrate 610. When the liquid crystal molecules maintain the vertical alignment state, when viewed from the front, the polarization axes of the first polarizing plate 800 and the second polarizing plate 850 are perpendicular to each other so that light leakage does not occur, but when viewed from the side, the first and second polarizing plates Light leakage may occur because the polarization angle of the polarization axes of the

fields

800 and 850 is increased. In order to compensate for such light leakage,

optical compensation films

8 and 5 such as biaxial films or uniaxial films may be disposed.

As described above, since the liquid crystal layer 700 of the liquid crystal display includes a ferroelectric liquid crystal, the alignment of the liquid crystal layer together with the nematic liquid crystal may be uniform and the stability of the alignment may be improved. Therefore, the luminance of the liquid crystal display including the liquid crystal layer 700 may be improved. In addition, by further including a reactive mesogen material in at least one of the liquid crystal layer 700 and the first and second alignment layers 540 and 640, the alignment speed of the liquid crystal molecules in the liquid crystal layer 700 is increased, and the alignment is performed. The angle is also increased, the optical properties can be improved.

Hereinafter, driving of the liquid crystal display will be briefly described with reference to the structures of the first and

second electrodes

530 and 630 illustrated in FIGS. 17A and 17B.

When there is no potential difference between the first and

second electrodes

530 and 630, the liquid crystal molecules may be arranged in a first direction perpendicular to the first or second electrode surfaces 530 and 630.

When a potential difference occurs between the first and

second electrodes

530 and 630, a second alignment direction in which the alignment of the liquid crystal molecules is substantially parallel to an extension direction of the first or

second electrodes

530 and 630. Can be changed to In the present exemplary embodiment, the second alignment direction of the liquid crystal molecules may be different depending on which one is positioned between the first and second electrodes. Liquid crystal molecules positioned between the first and second electrodes on which the first and second slits are formed may have a second alignment direction in a direction perpendicular to the first and second slits. Meanwhile, the liquid crystal molecules positioned between the first and second electrodes spaced apart from the first and second slits may have a second direction in a direction twisted about 45 ° or about 135 ° with respect to the first and second slits. It may have an orientation direction.

second electrodes

530 and 630, the alignment directions may be changed in at least two stages of the liquid crystal molecules to be finally arranged in the second alignment direction. Can be. For example, the operation of changing the alignment directions of the liquid crystal molecules may include a first alignment step and a second alignment step that occur sequentially. The reason why the liquid crystal molecules of the liquid crystal layer 700 do not change in a desired direction is due to the structure of the first and

second electrodes

530 and 630. This is because the strength or the shape of the electric field generated between 630 and 630 is different.

Hereinafter, a first alignment step and a second alignment step in which a potential difference occurs between the first and

second electrodes

530 and 630 to sequentially change liquid crystal molecules will be described.

The first alignment step (as soon as a potential difference occurs between the first and second electrodes) may be a process of changing the liquid crystal molecules aligned in the first alignment direction to have a third alignment direction. The third alignment direction may include directions different from the first or second alignment direction.

The alignment direction of the liquid crystal molecules in the first alignment step is changed according to the position between the first and

second electrodes

530 and 630. When a potential difference occurs between the first and

second electrodes

530 and 630, a relatively strong electric field may be formed at a portion far from the first and second slits. In addition, a portion where the first and second slits are formed may have a relatively weak electric field.

The liquid crystal molecules in a portion in which a relatively strong electric field is generated may change from the first alignment direction to the third alignment direction, and the third alignment direction may be any direction and may not be easy to predict. The liquid crystal molecules of a portion in which a relatively weak electric field is generated may be changed from the first alignment direction to a third alignment direction, and the third alignment direction is a third alignment in a direction perpendicular to the first and second slits. Direction.

The second alignment step (after a predetermined time after the potential difference occurs between the first and second electrodes) may be a process of changing the liquid crystal molecules aligned in the third alignment direction to have the second alignment direction. have. In detail, the liquid crystal molecules of the portion in which the relatively strong electric field is generated may be changed to have a second alignment direction deviated by about 45 ° or about 135 ° with respect to the first and second slits. The liquid crystal molecules of the portion in which the relatively weak electric field is generated may have a second alignment direction in a direction perpendicular to the first and second slits. As a result, the liquid crystal molecules between the first and

second electrodes

530 and 630 may be changed in a desired second alignment direction.

Meanwhile, when the reactive mesogen is included in the liquid crystal layer 700 or the first or second alignment layers 540 and 640, the liquid crystal molecules having the first alignment direction may be formed in the first and second electrodes 530. When a potential difference occurs between the 630, it may immediately change in the second alignment direction. That is, the liquid crystal molecules may be changed from the first alignment direction to the second alignment direction by omitting the step of changing in the third alignment direction.

Hereinafter, structures of the first and

second electrodes

530 and 630 will be described in detail. Hereinafter, the slit structure of the first electrode will be described in detail. The structure of the first and second electrodes described below is exemplary, but the present invention is not limited thereto.

18A to 18E are plan views illustrating structures of first and second electrodes according to embodiments of the present invention.

Referring to FIG. 18A, the first electrode 530 may include a first slit 532 formed along an edge of the first electrode 530. When the first electrode 530 is rectangular in plan view, the first slit 532 may have a rectangular ring shape. The second electrode 630 penetrates the center of the second electrode 630 and extends in a first direction D1, and a second line 632a penetrates the center of the second electrode 630. The second slit 632 may include a second line 632 b extending in the direction D2. The first and second directions D1 and D2 may be vertical. In addition, the first and

second lines

632a and 632b may communicate with each other. For example, the second electrode 630 may have a cross shape.

Referring to FIG. 18B, the first electrode 530 may include a first slit 532 formed along the edge of the first electrode 530. Unlike in FIG. 18A, the first slit 532 is not formed continuously but may include a cut portion in the middle. For example, the cut portion of the first slit 532 may be formed in the middle of the side. When the first electrode 530 is rectangular in plan view, the first slit 532 may have a cramp shape disposed at each vertex. Since the second electrode 630 is substantially the same as the structure described with reference to FIG. 18A, a detailed description thereof will be omitted. For example, the second slit 632 of the second electrode 630 may have a cross shape.

In the present embodiment, the first slit 532 may be formed so as not to overlap the second slit 632. For example, a portion of the second slit 632 may overlap the cut portion of the first slit 532.

Referring to FIG. 18C, the first electrode 530 may include a first slit 532 formed along the edge of the first electrode 530. Unlike in FIG. 18A, the first slit 532 is not formed continuously but may include a cut portion in the middle. For example, the cut portion of the first slit 532 may be formed at the vertex. In the plan view, when the first electrode 530 is a quadrangle, the first slit 532 may have a line shape disposed at each side. Since the second electrode 630 is substantially the same as the structure described with reference to FIG. 18A, a detailed description thereof will be omitted.

Referring to FIG. 18D, the first electrode 530 has a first line 532a formed along an edge of the first electrode 530 and a cross-shaped second penetrating the center of the first electrode 530. It may include a first slit 532 that includes a line 532b. The first slit 532 may include cutting portions. The first electrode 530 may be divided into four regions by the first slit 532 of the first electrode 530. The second electrode 630 may include a cross-shaped second slit 632 penetrating the center of four regions of the first electrode 530. According to the present embodiment, the first and

second slits

532 and 632 may be formed so as not to overlap each other.

Referring to FIG. 18E, the first electrode 530 may include a cross-shaped stem portion 530a and a plurality of branch portions 530b extending radially from the stem portion 530a. The stem portion 530a may be provided in various shapes, for example, may have a cross shape. The branch portions 530b may extend to four regions divided by the cross-shaped stem portion 530a. The branch portions 530b may extend toward vertices, respectively, and may be spaced apart from each other by a micrometer (μm) unit. Branches 530b of the neighboring regions may be mirror images of each other. The first electrode 530 may include line-shaped first slits 532 spaced apart from the branch portions 530b. The distance between the first slits 532 may be several μm. The first slits 532 may not be in communication with each other, but may have separate shapes. Meanwhile, in the present embodiment, the second electrode 630 does not have a slit and thus may be a patternless electrode.

Referring to FIG. 18F, the first electrode 530 includes a stem portion 530a and branches 530b similarly to the first electrode 530 of FIG. 18E, but is spaced apart from the branches 530b. The first slits 532 may be in communication with each other. The second electrode 630 has no slit and thus may be a patternless electrode.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Example 2. However, the following examples are provided to illustrate the present invention, and the present invention is not limited to the following examples and may be variously modified and changed.

Liquid crystal display LVA

Comparative Example 2

A first display panel including a first electrode having a first slit having a square ring, a second display panel including a second electrode having a second slit having a cross shape, and filling the gap between the first and second display panels; The liquid crystal display device containing the liquid crystal layer was manufactured. The liquid crystal display is manufactured in a lattice structure vertical alignment (VA) mode having four domains.

Example 9

The liquid crystal display of Example 8 was manufactured in the same manner except for the liquid crystal layer material.

Example 13

For Comparative Example 2 and Examples 8 to 14 components and the liquid crystal layer thickness, see Table 2 below.

TABLE 2

	Nematic liquid crystal	Smectic liquid crystal		Liquid crystal layer thickness
	Nematic liquid crystal	Non-chiral ingredients	Chiral ingredients	Liquid crystal layer thickness
Comparative Example 2	100 wt%	0	0	4.5 ㎛
Example 8	97 wt%	2.8 wt%	0.2 wt%	4.5 ㎛
Example 9	95 wt%	4.5 wt%	0.5 wt%	4.5 ㎛
Example 10	90 wt%	9.7 wt%	0.3 wt%	4.5 ㎛
Example 11	90 wt%	9.0 wt%	1.0 wt%	4.5 ㎛
Example 12	85 wt%	14.3 wt%	0.7 wt%	4.5 ㎛
Example 13	80 wt%	18.6 wt%	1.6 wt%	4.5 ㎛
Example 14	70 wt%	29.1 wt%	0.9 wt%	4.5 ㎛

Permeability Evaluation

19 is a graph comparing transmittances of the liquid crystal display of Comparative Example 2 and Examples 8 to 14. 19 are graphs illustrating transmittance according to applied voltage. The x-axis of FIG. 3 is an applied voltage and a unit is [V], and the y-axis shows transmittance.

Referring to FIG. 19, the transmittance of the liquid crystal display devices of Examples 8 to 14 exhibits excellent overall transmittance as compared to the liquid crystal display device of Comparative Example 2. In more detail, Example 8 and Example 9 compared to Comparative Example 2 in terms of the transmittance is insignificant but it can be seen that the transmittance is improved. In addition, the liquid crystal displays of Examples 10 to 14 exhibit a transmittance close to about 1.2, and exhibit excellent transmittances compared to the liquid crystal display of Comparative Example 2 having a transmittance of about 0.6.

From the above evaluation, it is predicted that the non-chiral smectic liquid crystal in the liquid crystal layers of Examples 8 to 14 induces the liquid crystal molecules to be uniformly and stably aligned. Therefore, it can be seen that the transmittances of the liquid crystal display devices of Examples 8 to 14 are superior to those of the liquid crystal display device of Comparative Example 2.

20A is a graph showing the transmittance of the liquid crystal display of Comparative Example 2 and the transmittance according to the amount of non-chiral components in the liquid crystal layer of the liquid crystal display of Examples 8 to 14, and FIG. 20B is a liquid crystal display of Comparative Example 2 Is a graph showing the transmittance of and the transmittance according to the amount of chiral components in the liquid crystal layer of the liquid crystal display devices of Examples 8 to 14. 20A and 20B, the x-axis shows the amount of the non-chiral component or chiral component, the unit is [% by weight], and the y-axis shows the transmittance.

Referring to FIG. 20A, as the non-chiral component in the liquid crystal layer increases, the transmittance of the liquid crystal display devices may be improved. In more detail, in Comparative Example 2, that is, when there is no non-chiral component, the transmittance is about 0.63. However, as the non-chiral component in the liquid crystal layer increases, the transmittance of the liquid crystal display devices is improved. In addition, when the non-chiral component in the liquid crystal layer is about 9.7 wt% or more, it can be seen that the transmittance is improved to about 0.8.

Referring to FIG. 20B, it can be seen that as the chiral component in the liquid crystal layer increases, the transmittance of the liquid crystal display devices is somewhat irregular but improves overall. In more detail, Comparative Example 2, that is, when there is no chiral component, transmittance of about 0.63 is shown, but it can be seen that as the non-chiral component in the liquid crystal layer increases, the transmittance of the liquid crystal display devices improves. In addition, when the chiral component in the liquid crystal layer is about 0.9% by weight or more, it can be seen that the transmittance is improved to about 0.8.

Texture Evaluation

21A to 21H and 22A to 22H are applied to the liquid crystal display devices of Comparative Examples 2 and 8 to 14, and after applying a voltage of 7V, the white polarizer is rotated by rotating the cross polarizer. Black images were obtained.

The textures of FIGS. 21A-21H are white images under a cross polarizer. In more detail, the white images show a case where the angle between the cross polarizer and the liquid crystal molecules of the liquid crystal layer is 45 °, and the light is passed through the liquid crystal layer and is illuminated. This can be confirmed in Equation 1 above.

21A to 21H are textures of Comparative Example 2 and Examples 8 to 14, respectively. Referring to Fig. 21A, a defect that looks black at the edge portions of the slit or the boundary of the slit is shown. 21B to 21H, it can be seen that defects at the boundary of the slit as well as the edge portions of the slit are removed.

The textures of FIGS. 22A-H are black images under a cross polarizer. In more detail, the black images are a case where the angle between the cross-polarizing plate and the liquid crystal molecules of the liquid crystal layer is 0 °. Show them. In the above formula 1, when the value of φ is 0 °, the value of sin ^{2 has} a value of 0 and the transmittance is zero.

22A to 22H are textures of Comparative Example 2 and Examples 8 to 14, respectively. Referring to FIG. 22A, light leakage is seen at edges of the slit or at the boundary of the slit. 22B to 22H, it can be seen that the light leakage phenomenon is removed from the edge portion and the boundary of the slit in comparison with FIG. 22A.

23A and 23B are graphs showing gray levels of the textures of Comparative Example 2 and Examples 8 to 14. FIG. 23A and 23B evaluate at 256 (2 ⁸ ) gray levels, show gray closer to black as 0 goes, and show the darkness of gray at a level from 0 to 255. FIG.

FIG. 23A shows the gray levels of the textures of FIGS. 21A-21H, which are often seen near 150-230 of the gray level as white images. In Comparative Example 2 of FIG. 21A, a lot is seen between gray levels of about 150 to 200, and it can be seen that the width of the peak is wide. Examples 8-14 of FIGS. 21B-21H show much between gray levels of about 200-230, and it can be seen that the peak width is narrower than that of Comparative Example 2. FIG. In addition, it can be seen that as Example 8 goes to Example 14, a lot is seen around the gray level of about 230, and the peak width is narrowed.

FIG. 23B shows the gray level of the texture of FIGS. 22A-22H, which is seen much near zero of the gray level as black images. In Comparative Example 2 of FIG. 22A, a lot is seen between gray levels of about 30 to 50, and it can be seen that the width of the peak is wide. Examples 8-14 of FIGS. 22B-H show a lot between gray levels about 0-25, and it can be seen that the width of the peak is narrower than the peak width of Comparative Example 2. In addition, it can be seen that as Example 8 goes to Example 14, a lot is seen around the gray level about 0, and the peak width is also narrowed.

Referring to the graphs of FIGS. 23A and 23B, in the case of the liquid crystal layer including the smectic material, the alignment of the liquid crystal molecules in the liquid crystal layer is uniform and stable compared to that of the liquid crystal layer not containing the ferroelectric material. It can be seen that the improvement.

FIG. 24A illustrates the transmittance changed according to the distance of the slit after cutting the textures of FIGS. 21A to 21H in one direction. Referring to FIG. 24A, it can be seen that Comparative Example 2 exhibits a transmittance of 130 to 180 around the slit, and is shown to be blacker than the outer portion of the slit. Examples 8-14 show a transmittance of about 180-230. Therefore, it can be seen that the transmittances of Examples 8 to 14 are higher than those of Comparative Examples 2 than those of the slits.

FIG. 24B illustrates the transmittance changed according to the distance of the slit after cutting the textures of FIGS. 22A to 22H in one direction. Referring to FIG. 24B, light leakage is exhibited by showing transmittance of 80 or more around the slits of Comparative Example 2. Around the slits of Examples 8 to 14, light leakage defects of 80 or less seem to be somewhat resolved.

[[액정 표시 장치 FFS 모드]][[Liquid Crystal Display FFS Mode]]

25 and 26, the liquid crystal display device 2 may include a first substrate 900, a second substrate 1000 facing the first substrate 900, and the first substrate 900. The liquid crystal layer 1100 is formed between the second substrate 1000. The first substrate 900 is called a thin film transistor substrate because it corresponds to a substrate on which thin film transistors are formed, and the second substrate 1000 is called a color filter substrate because it corresponds to a substrate on which color filters CF are formed.

The first substrate 900 includes a first insulating substrate 901, a plurality of gate lines, a plurality of data lines, and a plurality of pixels PXL. The first insulating substrate 901 has a substantially rectangular shape and is made of a transparent insulating material.

The gate lines extend in a first direction on the first insulating substrate 901. The gate lines are, for example, n + p gate lines GL1, ..., GLn, GLn + 1, ..., GL (n + p) -1, GLn + p.

The data lines extend in a second direction crossing the first direction with the gate lines and the insulating layer interposed therebetween. The data lines are composed of, for example, m + q data lines DL1, ..., DLm, DLm + 1, ..., DL (m + q) -1, DLm + q. Each pixel includes one of the gate lines GL1, ..., GLn, GLn + 1, ..., GL (n + p) -1, GLn + p and the data lines DL1, ... , DLm, DLm + 1, ..., DL (m + q) -1, DLm + q).

Since each pixel PXL has the same structure, the n-th gate line GLn, the m-th data line DLm, and one pixel PXL are illustrated in FIG. 23 for convenience of description.

Each pixel PXL includes a thin film transistor, a pixel electrode PE connected to the thin film transistor, a protective layer 913 covering the pixel electrode PE, and a common electrode spaced apart from the pixel electrode PE. (CE). The thin film transistor includes a gate electrode GE, a gate insulating layer 911, a semiconductor pattern SM, a source electrode SE, and a drain electrode DE.

The gate electrode GE may protrude from the n-th gate line GLn or may be provided on a portion of the n-th gate line GLn.

The gate electrode GE may be made of metal. The gate electrode GE may be made of nickel, chromium, molybdenum, aluminum, titanium, copper, tungsten, and an alloy thereof. The gate electrode GE may be formed of a single layer or multiple layers using the metal. For example, the gate electrode GE may be a triple layer in which molybdenum, aluminum, and molybdenum are sequentially stacked, or a double layer in which titanium and copper are sequentially stacked. Or a single film of an alloy of titanium and copper.

The gate insulating layer 911 is provided on the entire surface of the first insulating substrate 901 to cover the nth gate line GLn and the nth gate line GLn.

The semiconductor pattern SM is provided on the gate insulating layer 911. A portion of the semiconductor pattern SM overlaps the gate electrode GE. The semiconductor pattern SM includes an active pattern ACT provided on the gate insulating layer 911 and an ohmic contact layer OC formed on the active pattern ACT. The active pattern ACT may be formed of an amorphous silicon thin film, and the ohmic contact layer OC may be formed of n ⁺ amorphous silicon thin film. The ohmic contact layer OC is provided between a portion of the active pattern ACT and a source electrode SE to be described later, and between another portion of the active pattern ACT and a drain electrode DE to be described later. The ohmic contact layer OC makes ohmic contact between the active pattern ACT, the source electrode SE, and the drain electrode DE, respectively.

The source electrode SE is provided branched from the m-th data line DLm. The source electrode SE is formed on the ohmic contact layer OC and a portion of the source electrode SE overlaps the gate electrode GE.

The drain electrode DE is provided spaced apart from the source electrode SE with the semiconductor pattern SM therebetween. The drain electrode DE is formed on the ohmic contact layer OC, and a portion of the drain electrode DE is provided to overlap the gate electrode GE.

The source electrode SE and the drain electrode DE may be made of nickel, chromium, molybdenum, aluminum, titanium, copper, tungsten, and alloys thereof. The source electrode SE and the drain electrode DE may be formed as a single layer or multiple layers using the metal. For example, the source electrode SE and the drain electrode DE may be double layers in which titanium and copper are sequentially stacked. Or a single film made of an alloy of titanium and copper.

The source electrode SE and the drain electrode DE are provided to be spaced apart from each other on the semiconductor pattern SM by a predetermined interval. Accordingly, an upper surface of the active pattern ACT between the source electrode SE and the drain electrode DE is exposed, and the source electrode SE and the drain are dependent on whether the voltage of the gate electrode GE is applied. It becomes the channel part CH which forms a conductive channel between the electrodes DE.

The pixel electrode PE is provided on the drain electrode DE and the gate insulating layer 911. The pixel electrode PE is provided directly on the portion of the drain electrode DE and the gate insulating layer 911 to directly contact the portion of the drain electrode DE and the gate insulating layer 911.

The pixel electrode PE may have a substantially rectangular shape in plan view, but is not limited thereto and may be provided in various shapes according to the shape of the pixel. The pixel electrode PE is formed as a plate without a pattern such as an opening therein.

The common electrode CE may include a pattern having an opening. According to an embodiment of the present invention, the common electrode CE may have a stripe structure extending in one direction and spaced at equal intervals from each other. In the present exemplary embodiment, the common electrode CE having the stripe structure is exemplarily described, but the structure of the common electrode CE is not limited thereto.

According to another embodiment of the present invention, the first substrate 900 may further include a first alignment layer 915 between the common electrode CE and the liquid crystal layer 1100. The first alignment layer 915 may pre-tilt the liquid crystal molecules in the liquid crystal layer 1100 in one direction. According to an embodiment, the first alignment layer 915 is made of poly-amic acid, polyimide, lecithin, nylon, and polyvinylalcohol (PVA). It may include at least one selected from. In another embodiment, the first alignment layer 915 may further include a reactive mesogen material.

According to another embodiment of the present invention, the second substrate 1000 may further include a second alignment layer 1015 between the color filter CF and the liquid crystal layer 1100. According to an embodiment, the second alignment layer 1015 is made of poly-amic acid, polyimide, lecithin, nylon, and polyvinylalcohol (PVA). It may include at least one selected from. According to another embodiment, the second alignment layer 1015 may further include a reactive mesogen material.

The liquid crystal layer 1100 may fill between the first and

second substrates

900 and 1000. According to an embodiment, the liquid crystal layer 1100 may include a negative nematic liquid crytal having a negative dielectric anisotropy, a positive nematic liquid crytal having a positive dielectric anisotropy, and a ferroelectric liquid. crystal). According to another embodiment, the liquid crystal layer 1100 may include a non-ferroelectric liquid crystal and a ferroelectric liquid crystal. The description of the liquid crystal layer 1100 is substantially the same as the liquid crystal layer described in the PVA mode, and thus a detailed description thereof will be omitted.

As described above, the liquid crystal layer 1100 of the liquid crystal display of the FFS mode (field fringe switching mode) includes a ferroelectric liquid crystal, thereby making the alignment of the liquid crystal layer uniform with the nematic liquid crystal and improving the stability of the alignment. have. Therefore, the luminance of the liquid crystal display including the liquid crystal layer 1100 may be improved. In addition, by further including a reactive mesogen material in the first and second alignment layers 915 and 1015, the alignment speed of the liquid crystal molecules in the liquid crystal layer 1100 may be increased, and the angle of the alignment may be increased to improve optical characteristics. Can be.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Example 3. However, the following examples are provided to illustrate the present invention, and the present invention is not limited to the following examples and may be variously modified and changed.

Liquid Crystal Display FFS Mode

Comparative Example 3

The liquid crystal display of FIGS. 1 and 2 including a first substrate including a common electrode having a stripe pattern and a pixel electrode of a plate, a second substrate, and a liquid crystal layer filling the first and second substrates. Was prepared. The liquid crystal display is manufactured in a field fringe switching (FFS) mode.

The liquid crystal display of Example 15 was manufactured in the same manner except for the liquid crystal layer material.

Example 18

Example 19

Example 20

Example 21

For Comparative Example 3 and Examples 15 to 21 components and the liquid crystal layer thickness, see Table 3 below.

TABLE 3

	Nematic liquid crystal	Smectic liquid crystal		Liquid crystal layer thickness
	Nematic liquid crystal	Non-chiral ingredients	Chiral ingredients	Liquid crystal layer thickness
Comparative Example 3	100 wt%	0	0	4.5 ㎛
Example 15	97 wt%	2.8 wt%	0.2 wt%	4.5 ㎛
Example 16	95 wt%	4.5 wt%	0.5 wt%	4.5 ㎛
Example 17	90 wt%	9.7 wt%	0.3 wt%	4.5 ㎛
Example 18	90 wt%	9.0 wt%	1.0 wt%	4.5 ㎛
Example 19	85 wt%	14.3 wt%	0.7 wt%	4.5 ㎛
Example 20	80 wt%	18.6 wt%	1.6 wt%	4.5 ㎛
Example 21	70 wt%	29.1 wt%	0.9 wt%	4.5 ㎛

Permeability Evaluation

27 is a graph comparing transmittances of the liquid crystal display of Comparative Example 3 and Examples 15 to 21. FIG. 27 are graphs illustrating the transmittance according to the applied voltage. The x-axis of FIG. 27 is an applied voltage and a unit is [V], and the y-axis shows transmittance.

Referring to FIG. 27, the transmittance of the liquid crystal display devices of Examples 15 to 21 exhibits excellent overall transmittance as compared to the liquid crystal display device of Comparative Example 3. FIG. In more detail, it can be seen that in Example 15, the effect is insignificant in terms of transmittance compared to Comparative Example 3, but the transmittance is improved. In addition, the liquid crystal display devices of Examples 16 to 20 exhibit transmittances of about 1.8 to 2.0, and exhibit excellent transmittance as compared to the liquid crystal display of Comparative Example 3 having a transmittance of about 1.5.

From the above evaluation, it is predicted that the non-chiral smectic liquid crystal in the liquid crystal layers of Examples 15 to 21 induces the liquid crystal molecules to be uniformly and stably aligned. Accordingly, it can be seen that the transmittances of the liquid crystal display devices of Examples 15 to 21 are superior to those of the liquid crystal display device of Comparative Example 3.

28A is a graph illustrating the transmittance of the liquid crystal display of Comparative Example 3 and the transmittance according to the amount of non-chiral components in the liquid crystal layer of the liquid crystal displays of Examples 15 to 21, and FIG. 28B is a liquid crystal display of Comparative Example 3; And a transmittance according to the amount of chiral component in the liquid crystal layer of the liquid crystal display devices of Examples 15 to 21. FIG. The x-axis in Figs. 28A and 28B represents the non-chiral component or the amount of the chiral component, the unit is [% by weight], and the y-axis represents the transmittance.

Referring to FIG. 28A, when the non-chiral component in the liquid crystal layer was about 10 wt%, the highest transmittance was shown. As the non-chiral component increased more than 10% by weight, the transmittance was slightly lower than that of the non-chiral component. However, only about 30% by weight of the non-chiral component showed lower permeability than Comparative Example 3.

Referring to FIG. 28B, when the chiral component is present in the liquid crystal layer, it is somewhat irregular, but when the chiral component is present in the liquid crystal layer, the transmittance is higher than that without the chiral component. However, only when the chiral component is about 0.7% by weight showed a lower permeability than without the chiral component.

Response rate evaluation

29A is a graph comparing the response speeds of the liquid crystal displays of Comparative Example 3 and Examples 15 to 21. FIG. The x-axis of FIG. 29A is an applied voltage and a unit is [V], and the y-axis is a response speed and a unit is [ms].

Referring to FIG. 29A, it can be seen that the response speeds of the liquid crystal display devices of Examples 15 to 21 are slightly increased than the response speeds of the liquid crystal display devices of Comparative Example 3. FIG. Meanwhile, the response speed of the liquid crystal display including the liquid crystal layer of Example 18 is substantially similar to that of Comparative Example 3. The increased response speed is expected to be lowered by changing the amount or type of nematic liquid crystals. Alternatively, the increased response speed is expected to be lowered by adding more reactive mesogen material to the liquid crystal layer.

29B is a graph illustrating the rising time and the polling time of the liquid crystal display of Comparative Example 3 and the rising time and the polling time of the liquid crystal display of Examples 15 to 21 according to the amount of non-chiral component. The x-axis of FIG. 29B represents the amount of non-chiral components, the unit is [% by weight], the y-axis represents time, and the unit represents [ms].

Comparative Example 3 shows a rising time of about 50 ms and a polling time of about 60 ms, and the response speed was measured to be about 110 ms. Referring to the data of Examples 15 to 21, the rising time and polling time are slightly increased compared to Comparative Example 3, and as a result, the response speed tends to be slightly increased.

FIG. 29C is a graph illustrating the rising time of the liquid crystal display devices of Comparative Example 3 and Examples 15 to 21 according to the applied voltage, and FIG. 29D is a falling time of the liquid crystal display devices of Comparative Example 3 and Examples 15 to 21. FIG. Is a graph showing the voltage depending on the applied voltage. In FIG. 29C and FIG. 29D, the x-axis represents an applied voltage, a unit is [V], a y-axis represents time, and a unit is [ms].

Referring to FIG. 29C, it can be seen that the rising speed of the liquid crystal display devices of Examples 15 to 21 is slightly increased than the rising speed of the liquid crystal display device of Comparative Example 3. FIG. On the other hand, the rising speed of the liquid crystal display including the liquid crystal layer of Example 18 is substantially similar to that of Comparative Example 3.

Referring to FIG. 29D, it can be seen that the polling speeds of the liquid crystal display devices of Examples 15 to 21 are slightly increased than the polling speed of the liquid crystal display device of Comparative Example 3. FIG. On the other hand, the polling speed of the liquid crystal display device including the liquid crystal layers of Examples 18 and 19 is substantially similar to that of Comparative Example 3.

It is expected that the slightly increased rising and falling rates can be lowered by changing the amount or type of nematic liquid crystal. Alternatively, the increased rising and falling rates are expected to be lowered by adding more reactive mesogen material to the liquid crystal layer.

Texture Evaluation

30A to 30H are applied to the liquid crystal display devices of Comparative Example 3, Examples 15 to 21, and after applying a voltage of 7V to rotate the cross-polarizing plate to obtain white images (white images). Referring to FIG. 30A, a defect that looks black at the edge portions of the slit or the boundary of the slit is shown. 30B to 30H, it can be seen that the images are generally brighter than in FIG. 30A. In addition, it can be seen that the images of FIGS. 30D to 30F remove not only the edge portions of the slits but also the defects at the boundaries of the slits.

31A to 31H, after applying a voltage of 7V to the liquid crystal display devices of Comparative Examples 3 and 15 and 21, black images were obtained by rotating the cross polarizer. Comparing the images of FIGS. 31A and 31B, it can be seen that light leakage is alleviated in the image of FIG. 31B.

32A and 32B are graphs showing the transmittance according to the distances of the textures of Comparative Example 3 and Examples 15 to 21. FIG. 32A and 32B evaluate at 256 (2 ⁸ ) gray levels, show gray closer to black as 0 goes, and show the darkness of gray at a level from 0 to 255. FIG.

32A shows the gray levels of the textures of FIGS. 30A-30H, many of which are seen near 150-230 of the gray levels as white images. In FIG. 32A, Comparative Example 3 is seen a lot between gray levels of about 150 to 200, and it can be seen that the width of the peak is wide. Examples 15, 2, and 5 are seen a lot between gray levels of about 180 to 200, and the peak width is narrower than the peak width of Comparative Example 3. In addition, Examples 17 and 18 can be seen to be seen a lot between about 190 to 230.

FIG. 32B shows the gray levels of the textures of FIGS. 31A-31H, which are often seen between 0-50 of the gray level as black images. Comparative Example 3 shows two peaks at about 50 and about 130, respectively, and it can be seen that the width of the peak is wide. Examples 15-19 show peaks at about 20, 60 and 150, but it can be seen that the peak at 20 is the highest and the width is somewhat narrow.

Referring to the graphs of FIGS. 32A and 32B, although the effective side is generally insignificant compared to Comparative Example 3, it can be seen that the liquid crystal display devices of Examples 17 and 19 exhibit better gray levels than Comparative Example 3. FIG. It can be seen that, in the case of the liquid crystal layer including the smectic material, the alignment of the liquid crystal molecules in the liquid crystal layer is uniform and stable compared to the liquid crystal layer containing no ferroelectric material, thereby improving the brightness of the liquid crystal display device.

FIG. 33A illustrates the transmittance changed according to the distance of the slit after cutting the textures of FIGS. 30A to 30H in one direction. Referring to FIG. 32A, it can be seen that Comparative Example 3 exhibits a transmittance of 120 around the slit, so that it appears blacker than the outer portion of the slit. Example 17 and Example 18 exhibit a transmission of about 140. Accordingly, it can be seen that the transmittances of Examples 17 and 18 are higher than those of Comparative Example 3 around the slits.

FIG. 33B illustrates the transmittance changed according to the distance of the slit after cutting the textures of FIGS. 31A to 31H in one direction. Referring to FIG. 32B, light transmission is poor due to the transmittance of 80 around the slits of Comparative Example 3. Around the slits of Example 17 and Example 18, light leakage defects of 80 or less seem to be somewhat resolved.

[[액정 표시 장치 IPS 모드]][[Liquid Crystal Display IPS Mode]]

34 and 35, the liquid crystal display device B is configured such that the upper sign 1300 and the lower sign 1200 are opposed to each other, and the liquid crystal layer 1400 is disposed between the upper sign 1300 and the lower sign 1200. ) Is intervened. The liquid crystal display device B may be in an in plane switching mode.

The lower sign 1200 may include a thin film transistor T, a common electrode 18, and a pixel electrode 30 for each of the plurality of pixel regions P defined in the transparent insulating first substrate 1210. The thin film transistor T may include a semiconductor layer 22 having a gate electrode 14, an insulating film 20 interposed therebetween, a source configured to be spaced apart from each other on the semiconductor layer 22; The

drain electrodes

24 and 26 may be included.

The common electrode 18 and the pixel electrode 30 may be spaced apart from each other in parallel on the same first substrate 1210. The common electrode 18 may be made of the same material as the gate electrode 14, and the pixel electrode 30 may be made of the same material as the source and drain

electrodes

24 and 26.

A gate line GL extending along a first side of the pixel region P and a data line DL extending in a second side direction perpendicular thereto are configured to apply a voltage to the common electrode 18. The common wiring CL may be provided. The common line CL may extend along the third side of the pixel area P spaced in parallel with the gate line GL. In the pixel region, the common electrode 18 having the first pattern and the pixel electrode 30 may be provided as the second pattern. The first pattern may have a structure that does not overlap the second pattern. For example, the common electrode 18 may have a first pattern extending perpendicular to the common line CL and spaced in parallel to each other. The pixel electrode 30 may have a second pattern spaced apart from the common electrode 18 in parallel with the common electrode 18. In this case, the first pattern and the second pattern may not overlap each other. Although the first and second patterns are described as having a line shape in the present embodiment, the structure of the first and second patterns is not limited in the present invention.

The upper sign 1300 includes a black matrix 42 formed on a transparent insulating second substrate 1310 corresponding to the gate line GL, the data line DL, and the thin film transistor T, and the pixel. And

color filters

44a and 44b formed corresponding to the area P. FIG.

According to another embodiment of the present invention, the lower sign 1200 may further include a first alignment layer 32 between the common electrode 30 and the liquid crystal layer. The first alignment layer 32 may pre-tilt the liquid crystal molecules in the liquid crystal layer 1400 in one direction. According to one embodiment, the first alignment layer 32 is a group consisting of poly-amic acid, polyimide, lecithin, nylon, polyvinylalcohol (PVA). It may include at least one selected from. In another embodiment, the first alignment layer 32 may further include a reactive mesogen material.

According to another embodiment of the present invention, the upper sign 1300 may further include a second alignment layer 52 between the

color filters

44a and 44b and the liquid crystal layer 1400. According to one embodiment, the second alignment layer 52 is a group consisting of poly-amic acid, polyimide, lecithin, nylon, polyvinylalcohol (PVA). It may include at least one selected from. According to another embodiment, the second alignment layer 52 may further include a reactive mesogen material.

According to an embodiment, the liquid crystal layer 1400 may include a negative nematic liquid crytal having a negative dielectric anisotropy, a positive nematic liquid crytal having a positive dielectric anisotropy, and a ferroelectric liquid. crystal). According to another embodiment, the liquid crystal layer 300 may include a non-ferroelectric liquid crystal and a ferroelectric liquid crystal. Description of the liquid crystal layer 1400 is substantially the same as the liquid crystal layer described in the PVA mode, and thus a detailed description thereof will be omitted.

As described above, since the liquid crystal layer 1400 of the liquid crystal display of the IPS mode (in plane mode) includes a ferroelectric liquid crystal, the liquid crystal layer may be made uniform in addition to the nematic liquid crystal and the stability of the alignment may be improved. Therefore, the luminance of the liquid crystal display including the liquid crystal layer 1400 may be improved. In addition, by further including the reactive mesogen material in the first and second alignment layers 32 and 52, the alignment speed of the liquid crystal molecules in the liquid crystal layer 1400 may be increased, and the angle of the alignment may be increased, thereby improving optical characteristics. Can be.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Example 4. However, the following examples are provided to illustrate the present invention, and the present invention is not limited to the following examples and may be variously modified and changed.

LCD Display IPS Mode

1 and 2 including a first substrate comprising a common electrode having a line pattern and a pixel electrode having a line pattern, a second substrate, and a liquid crystal layer filling between the first and second substrates The liquid crystal display device of was manufactured. The liquid crystal display is manufactured in IPS mode.

The liquid crystal display of Example 22 was manufactured in the same manner except for the liquid crystal layer material.

Example 27

For Comparative Example 4 and Examples 22 to 28 components and the liquid crystal layer thickness, see Table 4 below.

Table 4

	Nematic liquid crystal	Smectic liquid crystal		Liquid crystal layer thickness
	Nematic liquid crystal	Non-chiral ingredients	Chiral ingredients	Liquid crystal layer thickness
Comparative Example 4	100 wt%	0	0	4.5 ㎛
Example 22	97 wt%	2.8 wt%	0.2 wt%	4.5 ㎛
Example 23	95 wt%	4.5 wt%	0.5 wt%	4.5 ㎛
Example 24	90 wt%	9.7 wt%	0.3 wt%	4.5 ㎛
Example 25	90 wt%	9.0 wt%	1.0 wt%	4.5 ㎛
Example 26	85 wt%	14.3 wt%	0.7 wt%	4.5 ㎛
Example 27	80 wt%	18.6 wt%	1.6 wt%	4.5 ㎛
Example 28	70 wt%	29.1 wt%	0.9 wt%	4.5 ㎛

Permeability Evaluation

36 is a graph comparing the transmittances of the liquid crystal display of Comparative Example 4 and Examples 22 to 28. FIG. 36 are graphs illustrating transmittance according to an applied voltage. The x-axis of FIG. 36 is an applied voltage and a unit is [V], and the y-axis represents transmittance.

Referring to FIG. 36, the transmittance of the liquid crystal displays of Examples 22 to 28 exhibits excellent overall transmittance as compared to the liquid crystal display of Comparative Example 4. However, Example 28 can be seen that slightly less in terms of the transmittance compared to Comparative Example 4.

From the above evaluation, it is predicted that the non-chiral smectic liquid crystal in the liquid crystal layers of Examples 22 to 27 induces the liquid crystal molecules to be uniformly and stably aligned. Therefore, it can be seen that the transmittances of the liquid crystal display devices of Examples 22 to 27 are superior to those of the liquid crystal display device of Comparative Example 4.

37A is a graph illustrating the transmittance of the liquid crystal display of Comparative Example 4 and the transmittance according to the amount of non-chiral components in the liquid crystal layer of the liquid crystal display of Examples 22 to 28, and FIG. 37B is a liquid crystal display of Comparative Example 4 And a transmittance according to the amount of chiral component in the liquid crystal layer of the liquid crystal display of Examples 22 to 28. 37A and 37B, the x-axis shows the amount of the non-chiral component or chiral component, the unit is [% by weight], and the y-axis shows the transmittance.

Referring to FIG. 37A, when the non-chiral component in the liquid crystal layer was about 10 wt%, the highest transmittance was shown. As the non-chiral component increased more than 10% by weight, the transmittance was slightly lower than that of the non-chiral component. However, only about 30% by weight of the non-chiral component showed lower permeability than Comparative Example 4.

Referring to FIG. 37B, when the chiral component is present in the liquid crystal layer, it is somewhat irregular, but when the chiral component is present in the liquid crystal layer, the transmittance is higher than that without the chiral component. However, only when the chiral component is about 0.7% by weight showed a lower permeability than without the chiral component.

Response rate evaluation

38A is a graph comparing response speeds of liquid crystal display devices of Comparative Example 4 and Examples 22 to 28. FIG. In FIG. 38A, the x-axis represents an applied voltage and a unit is [V], and the y-axis represents a response speed and a unit is [ms].

Referring to FIG. 38A, it can be seen that the response speeds of the liquid crystal display devices of Examples 22 to 28 are slightly increased than those of the liquid crystal display device of Comparative Example 4. Meanwhile, the response speed of the liquid crystal display device including the liquid crystal layers of Examples 22 and 2 is substantially similar to that of Comparative Example 4. The increased response speed is expected to be lowered by changing the amount or type of nematic liquid crystals. Alternatively, the increased response speed is expected to be lowered by adding more reactive mesogen material to the liquid crystal layer.

38B is a graph illustrating the rising time and the falling time of the liquid crystal display of Comparative Example 4 and the rising time and the falling time of the liquid crystal display of Examples 22 to 28 according to the amount of non-chiral component. The x-axis of FIG. 38B represents the amount of non-chiral components, the unit is [% by weight], the y-axis represents time, and the unit represents [ms].

Comparative Example 4 shows a rising time of about 50 ms and a polling time of about 30 ms, and the response speed was measured to be about 90 ms. Referring to the data of Examples 22 to 28, the rising time and the polling time are slightly increased compared to Comparative Example 4, and as a result, the response speed tends to be slightly increased.

38C is a graph illustrating the rising time of the liquid crystal displays of Comparative Examples 4 and 22 through 28 according to the applied voltage, and FIG. 38D is a falling time of the liquid crystal displays of Comparative Example 4 and Examples 22 to 28. Is a graph showing the voltage depending on the applied voltage. 38C and 38D, the x-axis represents the applied voltage, the unit is [V], the y-axis represents time, and the unit represents [ms].

Referring to FIG. 38C, it can be seen that the rising speed of the liquid crystal display devices of Examples 22 to 28 is slightly increased than the rising speed of the liquid crystal display device of Comparative Example 4.

Referring to FIG. 38D, it can be seen that the polling speeds of the liquid crystal display devices of Examples 22 to 28 are slightly increased than the polling speeds of the liquid crystal display devices of Comparative Example 4. On the other hand, the polling speed of the liquid crystal display device including the liquid crystal layers of Examples 25 and 26 is substantially similar to that of Comparative Example 4.

Texture Evaluation

39A to 39H apply white light to the liquid crystal display devices of Comparative Example 4 and Examples 22 to 28, and then rotate the cross polarizer to obtain white images. Referring to Fig. 39A, a defect that looks black at the edge portions of the slit or the boundary of the slit is shown. Referring to FIGS. 39B-39G, it can be seen that the images are generally brighter than in FIG. 39A. Further, it can be seen that the images of FIGS. 39D and 39F have eliminated defects at the edges of the slit as well as the edge portions of the slit.

40A to 40H are applied to the liquid crystal display devices of Comparative Example 4, Examples 22 to 28, and after applying a voltage of 7V to rotate the cross-polarizing plate to obtain black images (black images). Comparing the images of FIGS. 40A and 40B, it can be seen that light leakage is alleviated in the image of FIG. 40B.

41A and 41B are graphs showing transmittances according to distances of the textures of Comparative Example 4 and Examples 22 to 28. FIG. 41A and 41B evaluate at 256 (2 ⁸ ) gray levels, show gray closer to black as 0 goes, and show the darkness of gray at a level from 0 to 255. FIG.

FIG. 41A shows the gray levels of the textures of FIGS. 39A-39H, many of which are seen near 150-230 of the gray level as white images. In FIG. 41A, Examples 27 and 7 are seen somewhat more at about 150 adjacent portions than the gray level of Comparative Example 4, but Examples 22 to 5 are more observed at the portion higher than the gray level of Comparative Example 4.

FIG. 41B shows the gray level of the texture of FIGS. 40A-40H, which are often seen between 0-50 of the gray level as black images. In FIG. 41B, Example 28 is seen more at a higher gray level than the gray level of Comparative Example 4, but Examples 22 to 27 are observed much in the lower part than the gray level of Comparative Example 4. FIG.

Referring to the graphs of FIGS. 41A and 41B, although the effective side is generally insignificant compared to Comparative Example 4, it can be seen that the liquid crystal display devices of Examples 24 and 5 exhibit better gray levels than Comparative Example 4. FIG. It can be seen that, in the case of the liquid crystal layer including the smectic material, the alignment of the liquid crystal molecules in the liquid crystal layer is uniform and stable compared to the liquid crystal layer containing no ferroelectric material, thereby improving the brightness of the liquid crystal display device.

FIG. 42A illustrates the transmittance changed according to the distance of the slit after cutting the textures of FIGS. 39A to 39H in one direction. Referring to FIG. 41A, it is observed that Example 28 shows a lower transmittance than Comparative Example 4 in the portion around the slit, but Examples 22 to 3 show higher transmittance than Comparative Example 4.

FIG. 42B illustrates the transmittance changed according to the distance of the slit after cutting the textures of FIGS. 40A to 40H in one direction. Referring to FIG. 41B, Example 28 showed a significantly lower transmittance around the slit than Comparative Example 4, indicating that light leakage phenomenon in the portion around the slit was alleviated.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical idea or essential features thereof. You will understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims

A first substrate;

A second substrate spaced apart from and facing the first substrate;

A liquid crystal layer disposed between the first and second substrates;

A first electrode disposed between the first substrate and the liquid crystal layer and having a first slit; And

A second electrode disposed between the liquid crystal layer and the second substrate and having a second slit,

The liquid crystal layer, 1 to 50% by weight of an achiral smectic liquid crystal (achiral smectic liquid crystal); And an extra nematic liquid crystal.
The method of claim 1,

The first and second electrodes when viewed in a plan view, the liquid crystal display device is disposed so that the first and second slits do not overlap.
The method of claim 1,

The liquid crystal display device is a patterned vertical alignment (PVA) mode.
The method of claim 1,

A first alignment layer disposed between the first electrode and the liquid crystal layer; And

And a second alignment layer disposed between the second electrode and the liquid crystal layer.
The method of claim 4, wherein

At least one of the first or second alignment layers may include a reactive mesogen material.
The method of claim 1,

And the nematic liquid crystal comprises a negative nematic liquid crystal having negative dielectric anisotropy.
The method of claim 1,

The liquid crystal layer further comprises a chiral liquid crystal.
The method of claim 7, wherein

The chiral liquid crystal is a liquid crystal display device occupies 0.01% by weight to 10% by weight in the liquid crystal layer.
The method of claim 1,

The liquid crystal layer further comprises a reactive mesogen material.
A first substrate;

A second substrate spaced apart from and facing the first substrate;

A liquid crystal layer disposed between the first and second substrates;

A first electrode disposed between the first substrate and the liquid crystal layer and having a first slit; And

A second electrode disposed between the liquid crystal layer and the second substrate and having a second slit,

The liquid crystal layer is 3 to 50% by weight smectic liquid crystal; And extra nematic liquid crystals,

The smectic liquid crystal is 70 to 97% by weight of the non-chiral smectic liquid crystal; And 3 to 30% by weight of a chiral smectic liquid crystal.
The method of claim 10,

The liquid crystal layer further includes a chiral dopant.
The method of claim 11,

The chiral smectic liquid crystal has a higher spontaneous polarization characteristic than the chiral dopant.
The method of claim 10,

And the nematic liquid crystal comprises a nematic liquid crystal having negative dielectric anisotropy.
The method of claim 10,

The liquid crystal layer further comprises a reactive mesogen material.
First and second electrodes spaced apart from each other; And

And a plurality of liquid crystal molecules having a first alignment direction perpendicular to a surface of the first or second electrode when the potential difference is filled between the first and second electrodes and there is no potential difference between the first and second electrodes. Including a liquid crystal layer,

The liquid crystal layer, 1 to 50% by weight of an achiral smectic liquid crystal (achiral smectic liquid crystal); And extra nematic liquid crystals,

When a potential difference occurs between the first and second electrodes, the plurality of liquid crystal molecules change to have a second alignment direction substantially parallel to an extension direction of the first or second electrode,

The changing operation of the liquid crystal molecules includes a first alignment step and a second alignment step that occur sequentially,

In the first alignment step, the liquid crystal molecules are changed to have a third alignment direction different from the first or second alignment direction,

The liquid crystal display of claim 2, wherein the liquid crystal molecules of the third alignment direction are changed to have the second alignment direction in the second alignment step.
The method of claim 15,

Further comprising an alignment layer disposed between at least one of the liquid crystal layer and the first electrode, and between the liquid crystal layer and the second electrode,

At least one of the liquid crystal layer and the alignment layer includes a reactive mesogen material,

And a plurality of liquid crystal molecules change from the first alignment direction to the second alignment direction when a potential difference is generated between the first and second electrodes by the reactive mesogen.
The method of claim 15,

And the nematic liquid crystal comprises a negative nematic liquid crystal having negative dielectric anisotropy.
The method of claim 15,

The liquid crystal layer further comprises a chiral liquid crystal.
The method of claim 18,

The chiral liquid crystal is a liquid crystal display device occupies 0.01% by weight to 10% by weight in the liquid crystal layer.
The method of claim 15,

The liquid crystal layer further comprises a reactive mesogen material.
The method of claim 15,

At least one of the first and second substrates has a slit.
The method of claim 21,

The first electrode includes a first ring-shaped first slit extending along an edge of the first electrode,

The second electrode includes a cross-shaped second slit penetrating the center of the second electrode.
The method of claim 22,

When a potential difference occurs between the first and second electrodes,

Liquid crystal molecules positioned in the first and second slits have a second alignment direction in a direction perpendicular to the first and second slits,

The liquid crystal molecules spaced apart from the first and second slits have a second alignment direction having an angle of 45 ° or 135 ° to the first and second slits.
The method of claim 22,

The first slit of the first electrode has a cutting portion in the middle.
The method of claim 21,

The first electrode,

A cross-shaped stem portion penetrating the center of the first electrode; And

And branch portions extending radially from the stem portion and spaced apart from each other by a plurality of slits.
The method of claim 25,

When a potential difference occurs between the first and second electrodes,

And the liquid crystal molecules have a second alignment direction substantially parallel to a direction in which the slits of the branch portions extend.
First and second electrodes spaced apart from each other; And

And a plurality of liquid crystal molecules having a first alignment direction perpendicular to a surface of the first or second electrode when the potential difference is filled between the first and second electrodes and there is no potential difference between the first and second electrodes. Including a liquid crystal layer,

The liquid crystal layer is 3 to 50% by weight smectic liquid crystal; And an extra nematic liquid crystal, wherein the smectic liquid crystal comprises: 70 to 97% by weight of a non-chiral smectic liquid crystal; And 3 to 30 wt% of a chiral smectic liquid crystal,

When a potential difference occurs between the first and second electrodes, the orientation of liquid crystal molecules in the liquid crystal layer filled between the first and second electrodes is substantially parallel to the extending direction of the first or second electrode. Perform an operation that changes in a second orientation direction,

The changing operation of the liquid crystal molecules includes a first alignment step and a second alignment step that occur sequentially,

In the first alignment step, the liquid crystal molecules are changed to have a third alignment direction different from the first or second alignment direction,

The liquid crystal display of claim 2, wherein the liquid crystal molecules of the third alignment direction are changed to have the second alignment direction in the second alignment step.
The method of claim 27,

The liquid crystal layer further includes a chiral dopant.
The method of claim 28,

The chiral smectic liquid crystal has a higher spontaneous polarization characteristic than the chiral dopant.
The method of claim 27,

And the nematic liquid crystal comprises a nematic liquid crystal having negative dielectric anisotropy.
The method of claim 27,

The liquid crystal layer further comprises a reactive mesogen material.
The method of claim 27,

Further comprising an alignment layer disposed between at least one of the liquid crystal layer and the first electrode, and between the liquid crystal layer and the second electrode,

At least one of the liquid crystal layer and the alignment layer includes a reactive mesogen material,

And a plurality of liquid crystal molecules change from the first alignment direction to the second alignment direction when a potential difference is generated between the first and second electrodes by the reactive mesogen.
A first substrate;

A second substrate spaced apart from and facing the first substrate;

A liquid crystal layer disposed between the first and second substrates;

A plate-shaped common electrode disposed between the first substrate and the liquid crystal layer; And

A pixel electrode having a pattern defining an opening disposed between the common electrode and the liquid crystal layer,

The liquid crystal layer, 1 to 50% by weight of an achiral smectic liquid crystal (achiral smectic liquid crystal); And an extra nematic liquid crystal.
The method of claim 33, wherein

The liquid crystal display device is a liquid crystal display device of the field fringe switching (FFS) mode.
The method of claim 33, wherein

And an alignment layer disposed adjacent to the liquid crystal layer.
36. The method of claim 35 wherein

The alignment layer includes a reactive mesogen material.
The method of claim 33, wherein

And the nematic liquid crystal comprises a negative nematic liquid crystal having negative dielectric anisotropy.
The method of claim 33, wherein

And the nematic liquid crystal comprises a positive nematic liquid crystal having positive dielectric anisotropy.
The method of claim 33, wherein

The liquid crystal layer further comprises a chiral liquid crystal.
The method of claim 39,

The chiral liquid crystal is a liquid crystal display device occupies 0.01% by weight to 10% by weight in the liquid crystal layer.
The method of claim 33, wherein

The liquid crystal layer further comprises a reactive mesogen material.
A first substrate;

A second substrate spaced apart from and facing the first substrate;

A liquid crystal layer disposed between the first and second substrates;

A plate-shaped common electrode disposed between the first substrate and the liquid crystal layer; And

A pixel electrode having a pattern defining an opening disposed between the common electrode and the liquid crystal layer,

The liquid crystal layer is 3 to 50% by weight smectic liquid crystal; And an extra nematic liquid crystal, wherein the smectic liquid crystal comprises: 70 to 97% by weight of a non-chiral smectic liquid crystal; And 3 to 30% by weight of a chiral smectic liquid crystal.
The method of claim 42, wherein

The liquid crystal layer further includes a chiral dopant.
The method of claim 43,

The chiral smectic liquid crystal has a higher spontaneous polarization characteristic than the chiral dopant.
The method of claim 42, wherein

And the nematic liquid crystal comprises a nematic liquid crystal having negative dielectric anisotropy.
The method of claim 42, wherein

And the nematic liquid crystal comprises a nematic liquid crystal having positive dielectric anisotropy.
The method of claim 42, wherein

The liquid crystal layer further comprises a reactive mesogen material.
The method of claim 42, wherein

Further comprising an alignment layer disposed adjacent to the liquid crystal layer,

The alignment layer includes a reactive mesogen material.
A first substrate;

A second substrate spaced apart from and facing the first substrate;

A liquid crystal layer disposed between the first and second substrates;

A common electrode disposed between the first substrate and the liquid crystal layer and having a first pattern; And

A pixel electrode having a second pattern disposed between the first substrate and the liquid crystal layer and not overlapping the first pattern,

The liquid crystal layer, 1 to 50% by weight of an achiral smectic liquid crystal (achiral smectic liquid crystal); And an extra nematic liquid crystal.
The method of claim 49,

The liquid crystal display device is a liquid crystal display device in IPS (in plane switching) mode.
The method of claim 49,

And an alignment layer disposed adjacent to the liquid crystal layer.
The method of claim 51,

The alignment layer includes a reactive mesogen material.
The method of claim 49,

And the nematic liquid crystal comprises a negative nematic liquid crystal having negative dielectric anisotropy.
The method of claim 49,

And the nematic liquid crystal comprises a positive nematic liquid crystal having positive dielectric anisotropy.
The method of claim 49,

The liquid crystal layer further comprises a chiral liquid crystal.
The method of claim 55,

The chiral liquid crystal is a liquid crystal display device occupies 0.01% by weight to 10% by weight in the liquid crystal layer.
The method of claim 49,

The liquid crystal layer further comprises a reactive mesogen material.
A first substrate;

A second substrate spaced apart from and facing the first substrate;

A liquid crystal layer disposed between the first and second substrates;

A common electrode disposed between the first substrate and the liquid crystal layer and having a first pattern; And

A pixel electrode disposed between the first substrate and the liquid crystal layer and having a second pattern that does not overlap the first pattern,

The liquid crystal layer is 3 to 50% by weight smectic liquid crystal; And an extra nematic liquid crystal, wherein the smectic liquid crystal comprises: 70 to 97% by weight of a non-chiral smectic liquid crystal; And 3 to 30% by weight of a chiral smectic liquid crystal.
The method of claim 58,

The liquid crystal layer further includes a chiral dopant.
The method of claim 59,

The chiral smectic liquid crystal has a higher spontaneous polarization characteristic than the chiral dopant.
The method of claim 58,

And the nematic liquid crystal comprises a nematic liquid crystal having negative dielectric anisotropy.
The method of claim 58,

And the nematic liquid crystal comprises a nematic liquid crystal having positive dielectric anisotropy.
The method of claim 58,

The liquid crystal layer further comprises a reactive mesogen material.
The method of claim 58,

Further comprising an alignment layer disposed adjacent to the liquid crystal layer,

The alignment layer includes a reactive mesogen material.