KR102007538B1 - Liquid Crystal Display Device - Google Patents

Abstract

Provided is a liquid crystal display device. The liquid crystal display device is disposed between the first substrate, the second substrate spaced apart from the first substrate, the liquid crystal layer disposed between the first and second substrates, the first substrate and the liquid crystal layer, and the first slit (first a first electrode having a slit) and a second electrode having a second slit disposed between the liquid crystal layer and the second substrate. The liquid crystal layer may comprise 1 to 50% by weight of an achiral smectic liquid crystal; And extra nematic liquid crystals.

Description

Liquid crystal display device

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.

According to an embodiment of the present invention, when the first and second electrodes are viewed in a plan view, the first slit and the second slit may be disposed so as not to overlap.

According to another embodiment of the present invention, the liquid crystal display may be in a patterned vertical alignment (PVA) mode.

According to still another embodiment of the present invention, the liquid crystal display may include a first alignment layer disposed between the first electrode and the liquid crystal layer; And a second alignment layer disposed between the second electrode and the liquid crystal layer.

According to another embodiment of the present invention, at least one of the first or second alignment layers may include a reactive mesogen material.

According to another embodiment of the present invention, the nematic liquid crystal may include a negative nematic liquid crystal having negative dielectric anisotropy.

According to another embodiment of the present invention, the liquid crystal layer may further include a chiral liquid crystal.

According to another embodiment of the present invention, the chiral liquid crystal may occupy 0.01 wt% to 10 wt% in the liquid crystal layer.

According to another embodiment of the present invention, the liquid crystal layer may further include a reactive mesogen material.

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.

According to an embodiment of the present invention, the liquid crystal layer may further include a chiral dopant.

According to another embodiment of the present invention, the chiral smectic liquid crystal may have a higher spontaneous polarization characteristic than the chiral dopant.

According to another embodiment of the present invention, the nematic liquid crystal may include a nematic liquid crystal having negative dielectric anisotropy.

According to another embodiment of the present invention, the liquid crystal layer may further include a reactive mesogen material.

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.
FIG. 5 is a graph comparing transmittances of the liquid crystal display of Comparative Examples and Examples 1 to 7. FIG.
6A is a graph showing the transmittance of the liquid crystal display of the comparative example and the transmittance according to the amount of non-chiral component in the liquid crystal layer of the liquid crystal display of Examples 1 to 7. FIG.
6B is a graph showing the transmittance of the liquid crystal display of the comparative example 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 Examples and Examples 1 to 7. FIG.
8 is a graph illustrating the rising time and the polling time of the liquid crystal display of the comparative example, 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 Examples and Examples 1 to 7. FIG.
9B is a graph illustrating polling times of liquid crystal displays of Comparative Examples and Examples 1 to 7.
10A through 10H are white textures of the liquid crystal display of the comparative example and the first to seventh embodiments.
11A through 11H are black textures of the liquid crystal display of Comparative Example and Embodiments 1 through 7.
12A and 12B are graphs showing gray levels of the textures of Comparative Examples and Examples 1 to 7. FIG.
13A and 13B are graphs showing transmittances according to distances of the textures of Comparative Examples and Examples 1 to 7. 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.

[[Liquid crystal display]]

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.

[First and second electrode structure]

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.

(Liquid crystal layer_first Example )

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.

Negative heredity Anisotropy  Having Nematic  LCD

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 The 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 is unsubstituted or at least monosubstituted by CN, CF _{3 ,} or halogen, and CH ₂ Group may 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) 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 alkenyl oxy having 1 to 15 carbon atoms (wherein hydrogen May be substituted by CN, CF ₃ , or halogen atom, and -CH ₂ -group is -CH = CH-, -O-, -CO-, -COO-, -OOC-, -O- May be substituted by 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.

Positive oil field Anisotropy  Having Nematic  LCD

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

또는

이며, B는 -CH₂-CH₂- 또는 -C≡C- 이며, X¹는 수소 또는 할로겐(halogen)이며, m은 1 2,3, 또는 4이다. 화학식 23의 구체적인 예들이 다음에 도시된다.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 may be an alkyl group having up to 15 carbon atoms unsubstituted or at least monosubstituted by halogen, CN _3, or halogen, wherein at least one CH ₂ of these groups The group may be replaced by -O-, -S-, -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  LCD

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

CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₅ PhCOOPhPhCF ₃

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.

Dialogue 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% by weight to about 50% by weight. 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 cyclohexyl, 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 is the same or different linear alkyl of 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 A group may be optionally substituted by -CH = CH-, -O-, -CO-, -COO-, -OOC-, -O-OC-O- or -S-), X is hydrogen or halogen (halogen). Specific examples of Formulas 47 and 48 are shown below.

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 the formula 49 are shown below.

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

Formula 55

또는

이고, B1는

또는

이며, R²⁶ 및 R²⁷은 각각 독립적으로 수소 또는 할로겐(halogen)이며, R²⁸ 및 R²⁹는 독립적으로 탄소원자 8개 내지 16개의 알킬(alkyl) 또는 알콕시(alkoxy)이다. 상기 화학식 50의 구체적인 예들이 다음에 도시된다.
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 50 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.

(Liquid crystal layer_second Example )

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

또는

or

Formula 58

그룹이고, R'은 1 내지 4개의 탄소를 갖는 알킬 그룹이고, T는

이고, X는 적어도 하나의 카이럴 중심을 갖는 알킬 또는 할로겐 치환 알킬 그룹이며, Y는 불소 원자 이며, m는 0, 1 또는 2를 가지며, p는 2, 3 또는 4를 가지며, n는 10, 11 또는 12를 갖는다.
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

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

그룹을 포함한다.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

,

,

,

,

,

그룹 중 하나일 수 있다.

,

,

,

,

,

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 Chemical Formulas 66 to 70, R ^K Is an alkyl group containing 3 to 10 carbons, in which the -CH ₂ -adjacent to the ring in the alkyl can be replaced with -O-, and any -CH ₂ -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.

(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 Examples. 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

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.

<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 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.

<Example 2>

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.

<Example 3>

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 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.

<Example 4>

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

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.

<Example 6>

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 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.

<Example 7>

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 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.

Comparative Examples and Examples 1 to 7 components and the thickness of the liquid crystal layer refer to Table 1 below.

Nematic liquid crystal Smectic liquid crystal Liquid crystal layer thickness Non-chiral ingredients Chiral ingredients Comparative example 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

FIG. 5 is a graph comparing transmittances of the liquid crystal display of Comparative Examples and Examples 1 to 7. FIG. 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 transmittances of the liquid crystal displays of Examples 1 to 7 exhibit excellent overall transmittance as compared to the liquid crystal display of the comparative example. In more detail, in Example 1 and Example 2, the effect is insignificant in terms of transmittance as compared with the comparative example, 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 the comparative example 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 the comparative example.

6A is a graph showing the transmittance of the liquid crystal display of the comparative example, the transmittance according to the amount of the non-chiral component in the liquid crystal layer of the liquid crystal display of Examples 1 to 7, Figure 6b is a transmittance of the liquid crystal display of the comparative example, It is a graph showing the transmittance according to the amount of chiral components in the liquid crystal layer of the liquid crystal display devices 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, the comparative example, that is, when there is no non-chiral component shows a transmittance of about 0.67, 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 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, the comparative example, that is, when there is no chiral component, shows a transmittance of 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 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.

Response speed evaluation

7 is a graph comparing response speeds of the liquid crystal displays of Comparative Examples 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 are slightly increased than the response speeds of the liquid crystal display devices of the comparative example. Meanwhile, in Example 7, the response speed of the liquid crystal display including the liquid crystal layer including about 29.1 wt% of the non-chiral component is substantially similar to that of the comparative example. 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.

8 is a graph illustrating the rising time and the polling time of the liquid crystal display of the comparative example, 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.

The comparative example 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.

9A is a graph illustrating rising times of the liquid crystal displays of Comparative Examples and Examples 1 to 7, and FIG. 9B is a graph illustrating the polling times of the liquid crystal displays of Comparative Examples and Examples. 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, the rising time and the polling time of Examples 1 to 7 slightly increased compared to the comparative example. The increased rise time and polling time are expected to be lowered by adding more reactive mesogen material to the liquid crystal layer.

texture ( texture ) evaluation

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

10A to 10H and 11A to 11H are applied to the liquid crystal display devices of Comparative Examples, Examples 1 to 7, and after applying a voltage of 7V, rotate the cross polarizer to rotate white images and black. 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.

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, 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 °, so that the rotated upper polarizing plate has a polarization perpendicular to the polarized light passing through the liquid crystal layer and is dark. Show them. In the above formula 1, when the value of φ is 0 °, the value of sin ^{2 has} a value of 0, so that the transmittance is zero.

11A-11H are textures of Comparative Example, Examples 1-7, 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 Examples 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. The comparative example 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 the peak width of the comparative example. 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. The comparative example of FIG. 11A is seen much between gray levels about 30-50, and it can be seen that the width of the peak is wide. Examples 1-7 of FIGS. 11B-11H show much between gray levels about 0-25, and it can be seen that the width of the peak is narrower than the peak width of the comparative example. 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 Examples 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 higher transmittance around the slits than the comparative example.

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 the comparative example. Around the slits of Examples 1-7, light leakage defects of 20 to 60 seem to be somewhat resolved.

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.

100: first display panel 110: first substrate
120: first electrode 170: first alignment plate
200: second display panel 220: second electrode
270: second alignment plate 300: liquid crystal layer

Claims (14)

delete delete delete delete delete delete delete delete delete 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.

Images