KR102047521B1 - Composition for preparing homogeneously aligned liquid crystal layer, manufacturing method of liquid crystal display using the same and liquid crystal display - Google Patents

Abstract

The present invention relates to a liquid crystal composition for induction of horizontal alignment, a method of manufacturing a horizontal alignment liquid crystal display device using the same, and a liquid crystal display device thereof.
The present invention relates to a liquid crystal cell including a liquid crystal composition for horizontal alignment induction containing one or more types of alignment-induced photopolymerizable monomers represented by Formula 1, wherein the alignment-induced photopolymerizable monomers are photopolymerized by linearly polarized ultraviolet radiation. It is possible to provide a horizontal alignment liquid crystal display device including a liquid crystal layer in which a photopolymer layer is formed on a surface thereof, and a uniform horizontal alignment of the liquid crystal host is induced in an in situ manner, and in particular, the horizontal alignment liquid crystal device. The display device not only induces horizontal alignment of the liquid crystal in an in situ manner, but also realizes orientation stability in heat treatment after induction of orientation and further irradiation of linearly or unpolarized ultraviolet light after the heat treatment.

Description

Liquid crystal composition for horizontal orientation induction, a method of manufacturing a horizontal alignment liquid crystal display device using the same and a liquid crystal display device thereof

The present invention relates to a liquid crystal composition for horizontal alignment induction, a method for manufacturing a horizontal alignment liquid crystal display device using the same, and a liquid crystal display device thereof, and more particularly, contains at least one alignment-induced photopolymerizable monomer represented by Formula (1). The alignment-induced photopolymerizable monomer is photopolymerized by linearly polarized ultraviolet irradiation and induces a uniform horizontal alignment of the liquid crystal host in an in situ manner to the liquid crystal cell including the liquid crystal composition for horizontal alignment induction. Horizontal orientation where the induced photopolymerizable monomer has a polymerizable group at its end with a linear rigid-core group and a structural characteristic connected to a flexible alkyl group to ensure orientation stability even under heat treatment and further ultraviolet irradiation A liquid crystal composition for induction, a method of manufacturing a horizontally oriented liquid crystal display device using the same, and a liquid crystal display device thereof The.

A liquid crystal display (LCD) is thin and lightweight and is used in various applications, and generally includes an array substrate including a pixel array, an opposite substrate facing the array substrate, and a liquid crystal layer between the array substrate and the opposite substrate, The image is displayed by changing the light transmittance by adjusting the arrangement of the liquid crystal molecules of the liquid crystal layer.

Recently, many technologies have been proposed in the liquid crystal display market in relation to the initial alignment of liquid crystal molecules.

In the case of the most commonly used vertical alignment (VA) mode liquid crystal device, an alignment layer is essentially coated in order to vertically align the initial liquid crystal direction with respect to the substrate.

The alignment layer coating is a printing process, which may cause a problem in uniformity when applying a large area, and the energy cost is increased because the amount of loss of the alignment layer material is increased, the material cost is increased, and the high temperature process is essential.

Also, since liquid crystals do not have directivity in the initial electric field, the concept of line tilt angle should be introduced. In this case, polymer stabilization (PS) is essential. Only through the PS step, it is possible to form a multi-domain pixel with improved response speed and improved liquid crystal orientation. As such, in the vertical alignment mode, there is a problem of cost increase due to the alignment film coating and the pretilt process. Recently, a technique for solving the above problem by using a liquid crystal composition containing a special additive without the linear alignment film coating process has been actively attempted. .

On the other hand, as a relative concept of the vertical alignment mode, the horizontal alignment mode of the liquid crystal device also needs to coat the alignment layer on the substrate first to thermally stabilize the liquid crystal to align the liquid crystals on the substrate surface, and in the horizontal alignment mode after the thermal stabilization. A rubbing process is performed to impart anisotropy in a predetermined direction to the alignment film surface to align the liquid crystal in a predetermined direction.

As the most common commercialization technology, an orientation method using a polyimide (PI) layer coating and a rubbing process is applied. The orientation technique is based on the electrostatic problem generated during the rubbing process, the wear state of the rubbing cloth, and the substrate condition depending on the substrate condition. The problem of non-uniformity of orientation in some areas remains an important challenge to solve. Therefore, in order to increase the size of the liquid crystal display device and to increase the ultra fine resolution, securing the characteristics of the alignment and the uniformity is an important technical problem to be solved.

Currently, photo-alignment method is actively researched to solve these technical problems, and among them, a technique of inducing surface anisotropy for liquid crystal alignment by irradiating short wavelength high energy ultraviolet ray after coating polyimide (PI) photo-alignment layer This is applied to some mass production.

However, there is still a lack of characteristics of the efficiency and orientation of the process, and efforts to solve this problem continue.

Recently, research has been conducted on a method of inducing uniform alignment in an in situ manner by adding a photosensitive group applied to a photoalignment polymer alignment agent to a liquid crystal composition in the form of a polymerizable monomer.

However, the degree of directional induction of the liquid crystal is less than that of the cell (PI-IPS) fabricated by irradiating polarized UV after the polyimide (PI) alignment layer coating or the rubbing process, or the response speed and electro-optical properties are not satisfied. There is no problem.

In order to solve this problem, a technique of mixing nano-size rods with liquid crystal molecules and aligning them, an alignment technique using hydrophobic molecules, and an alignment technique using reactive mesogen (RM) have been reported.

Currently, monomers containing a photosensitive group, which have been applied to conventional photo-alignment polymers, have been studied in an in-situ orientation induction method using liquid crystal additives. That is, the conventional report is reactive having a functional group such as azo-benzene, cinnamoyl, chacon, chalmarine, coumarine, phenylene vinylene, phenylene acetylene, etc. Research on photoalignment by the use of mesogen (RM) compounds has been concentrated.

The photosensitive reactive mesogen (RM) is a photo-responsive mesogen compound which is dimerized by trans-cis isomerization or photochemical reaction in response to light of a specific wavelength, Due to the anisotropy, since absorption and light sensitivity exhibit dichroism differently depending on the direction of polarization, uniform horizontal alignment can be induced by linearly polarized light irradiation. However, in these cases, it is pointed out a problem that the stability of the orientation is lowered fundamentally due to the photosensitivity reversibility.

Accordingly, the present inventors have tried to improve the conventional problems, the orientation-induced photopolymerizable as an additive of a specific structure excluding the photosensitive functional group that is reversible of the photochemical reaction in the photosensitive reactive mesogen compound used in the conventional photoalignment The use of monomers greatly improves the stability of the orientation induced, wherein the orientation-induced photopolymerizable monomer is a photopolymerizable group linked to a flexible rigid alkyl group at its terminal about a linear rigid-core group. A liquid crystal cell is prepared from the liquid crystal composition for horizontal alignment induction containing the alignment-induced photopolymerizable monomer, and is irradiated with linearly polarized ultraviolet rays to the inner surface of the liquid crystal display device substrate by photopolymerization of the alignment-induced photopolymerizable monomer. Forming a photopolymer layer, inducing a uniform horizontal orientation of the liquid crystal host, in particular By also determine the properties and stability of orientation after the ointment, the present invention has been completed.

Republic of Korea Patent No. 1060829 (August 30, 2011) Republic of Korea Patent Publication 2016-0101193 (2016.08.24 published) International Publication WO2011-115338 (published Sep. 22, 2011)

Masanobu Mizusaki, Hiroshi Tsuchiya & Kiyoshi Minoura, LIQUID CRYSTALS, 2017, 44, 1-8.

An object of the present invention is to provide a liquid crystal composition for induction of horizontal alignment containing at least one type of orientation-induced photopolymerizable monomer represented by the formula (1).

Another object of the present invention is to provide a method of manufacturing a horizontal alignment type liquid crystal display device using the liquid crystal composition for horizontal alignment induction.

Another object of the present invention is to provide a horizontal alignment liquid crystal display device from the method of manufacturing the horizontal alignment liquid crystal display device.

In order to achieve the above object, the present invention is a liquid crystal composition for horizontal orientation induction containing one or more orientation-induced photopolymerizable monomer represented by Formula 1, wherein the orientation-induced photopolymerizable monomer is a linearly polarized UV The present invention provides a liquid crystal composition for horizontal alignment induction, which is in situ photopolymerized by irradiation to induce horizontal alignment of liquid crystals.

Formula 1

In Formula 1, C _A and C _B are each independently a aryl group, a cyclic group selected from C ₄ to C ₁₀ cycloalkyl group containing or not containing aryl (heteroaryl) or hetero elements Form a linear rigid-core group through the linking group X, and in each cyclic group, one or more hydrogen atoms may be substituted or unsubstituted with an alkyl group or a halogen group of C ₁ to C ₄ ,

X is a linking group connecting C _A and C _B and is a single bond, an ester group selected from -O-CO- or -CO-O-, -O-, -CH _2- , -CH ₂ O-, -CF _2- , -CF ₂ O-, -CH ₂ CH _2- , -CH ₂ CH ₂ O-, -CF ₂ CF ₂ -It is one linking group selected from, provided that a double bond, triple bond sensitive to light irradiation , Azo group (N = N), -CO-C = C- and -O-CO-C = C- excluding the linking group selected from the group,

n is an integer of 1 to 3, R ₁ , R ₂ are each independently

And _{(CH 2) m1 OOC-, -} R 1 = P 1 - (CH 2) m1 O-, P 1 - (CH 2) m1 -, P 1 - (CH 2) m1 COO- , or P ₁

R ₂ = P _2- (CH ₂ ) _{m 2} O-, P _2- (CH ₂ ) _{m 2-} , P _2- (CH ₂ ) _{m 2} COO- or P _2- (CH ₂ ) _{m 2} OOC-

m1 and m2 are the integers of 0-12 independently, and said P <_1> , P <_2> are each independently an acryl group, a methacryl group, an acrylamide group, or a methacryl amide group.

As a preferable example of the said orientation guide type photopolymerizable monomer, it is selected from the group which consists of the following compounds.

In the above, X, Y, R ₁ , R ₂ are as defined in the specification.

In another aspect, the present invention provides a first process for preparing a liquid crystal composition for induction of horizontal alignment consisting of a liquid crystal mixture containing at least one orientation-induced photopolymerizable monomer represented by Formula 1,

A second process of manufacturing a liquid crystal cell assembly by injecting the liquid crystal composition for horizontal alignment induction between a first substrate and a second substrate;

A horizontal alignment liquid crystal comprising a third process of inducing a horizontal alignment of liquid crystals by photopolymerization of the alignment-induced photopolymerizable monomer by irradiating in situ linearly polarized ultraviolet rays to the liquid crystal cell assembly to produce a liquid crystal display device A method of manufacturing a display device is provided.

In the method for manufacturing the horizontally oriented liquid crystal display device of the present invention, it is preferable that the total amount of at least one or more orientation-induced photopolymerizable monomers in the first step is contained in an amount of 0.01 to 5.0 wt% based on the liquid crystal host.

In-situ linearly polarized ultraviolet light treatment at an isotropic temperature of the liquid crystal composition for horizontal alignment induction in the third process, and after the heat treatment or liquid crystal of the liquid crystal composition for horizontal alignment induction after the heat treatment to the liquid crystal composition induced with the horizontal alignment of the liquid crystal after the third process Further irradiation of linearly or unpolarized ultraviolet light can be carried out at merchant temperatures.

In addition, the present invention includes a first substrate and a second substrate, said first substrate and said oriented inductive photopolymerizable monomer is in situ comprising a horizontally oriented induce liquid crystal composition injected between the two substrates (in situ) method Provided is a horizontal alignment liquid crystal display device including a photopolymer layer formed on the inner surfaces of upper and lower substrates while being photopolymerized by irradiated linearly polarized ultraviolet rays, and a liquid crystal layer in which horizontal alignment of liquid crystals is induced thereby.

The liquid crystal composition for horizontal alignment induction is composed of a liquid crystal mixture containing one or more types of alignment-induced photopolymerizable monomers represented by Formula 1, and the horizontal alignment liquid crystal display device according to the present invention is thermally polarized after alignment induction or linearly polarized after heat treatment. And horizontal alignment is stably maintained even after further irradiation of unpolarized ultraviolet rays.

The present invention provides an orientation-induced photopolymerizable monomer having a specific structure, which excludes a reversible photosensitive functional group of a photochemical reaction in a photosensitive reactive mesogen compound used in conventional photoalignment, thereby greatly increasing the stability of the induced orientation. Can be improved.

The orientation-induced photopolymerizable monomer of the present invention has a structure having an irreversible photopolymerization group connected to a flexible alkyl group at its end with a linear rigid-core group as a liquid crystal composition for horizontal orientation induction. A liquid crystal display including a liquid crystal layer prepared by fabricating a liquid crystal cell and irradiating the linearly polarized ultraviolet light to form a photopolymer layer on the inner surface of the liquid crystal display device substrate by photopolymerization of the alignment-induced photopolymerizable monomer and inducing a horizontal alignment in the process. The apparatus can realize a uniform horizontal alignment with excellent stability without the process of coating the alignment film, firing, rubbing.

In addition, the liquid crystal display device of the present invention can induce a horizontal orientation of the irreversible liquid crystal in an in situ manner from the structural characteristics of the alignment-induced photopolymerizable monomer, and due to the irreversibility of the orientation induction The stability of liquid crystal alignment with respect to can be greatly improved.

Therefore, the liquid crystal display device of the present invention will be applicable to all liquid crystal drive information devices such as mobile phones, table PCs, notebook computers, TVs. In particular, the present technology may be usefully used in the fabrication of high performance large sized and ultra high definition display devices, which are difficult to apply the conventional alignment layer rubbing process.

1 is a liquid crystal cell produced in Example 1 of the present invention, (a) is a photograph observed under a cross polarizer before irradiation of ultraviolet polarization, (b) is a micro-polarization micrograph of the liquid crystal device,
FIG. 2 is a liquid crystal display device manufactured after irradiation of ultraviolet polarized light using a circular mask in the liquid crystal cell of FIG. 1, wherein (a) is a photograph when the polarization direction and transmission axis are parallel to each other, and (b) is a polarization direction. And the picture when the transmission axis is 45 degrees,
FIG. 3 illustrates the liquid crystal display of FIG. 2. (a) is (B) is a photograph when the polarization direction and the transmission axis are parallel in the region irradiated with ultraviolet rays, (c) is a photograph when the polarization direction and the transmission axis are 45 degrees,
FIG. 4 is a polarization microscope result after heat treatment in the liquid crystal display of FIG. 3, wherein (a) and (c) are photographs when the polarization direction and transmission axis are parallel to each other, and (b) and (d) are the polarization direction and transmission. When the axis is 45 degrees,
FIG. 5 is a polarization microscope result of unpolarized ultraviolet irradiation to the heat-treated liquid crystal display of FIG. 4, wherein (a) and (c) are photographs when the polarization direction and transmission axis are parallel to each other, and (b) and (d) ) Is a photograph when the polarization direction and the transmission axis is 45 degrees,
FIG. 6 is a liquid crystal display device manufactured after irradiating ultraviolet polarized light using a circular mask to a liquid crystal cell manufactured in Example 2 of the present invention, wherein (a) is a photograph when the polarization direction is parallel to the transmission axis. , (b) is a photograph when the polarization direction and transmission axis is 45 degrees,
FIG. 7 illustrates the liquid crystal display of FIG. 6. (a) is (B) is a photograph when the polarization direction and the transmission axis are parallel in the region irradiated with ultraviolet rays, (c) is a photograph when the polarization direction and the transmission axis are 45 degrees,
Figure 8 is a liquid crystal cell produced in Example 3 of the present invention, in the after of the UV polarization using a circular mask irradiation produced a liquid crystal display device, (a) is a photograph at the time of the polarization direction and the transmission axis parallel , (b) is a photograph when the polarization direction and transmission axis is 45 degrees,
FIG. 9 illustrates the liquid crystal display of FIG. 8. (a) is (B) is a photograph when the polarization direction and the transmission axis are parallel in the region irradiated with ultraviolet rays, (c) is a photograph when the polarization direction and the transmission axis are 45 degrees,
FIG. 10 is a polarization microscope result after heat treatment in the liquid crystal display of FIG. 8, wherein (a) and (c) are photographs when the polarization direction and transmission axis are parallel to each other, and (b) and (d) are the polarization directions It is a photograph when the transmission axis is 45 degrees,
11 is a liquid crystal display device manufactured after irradiation of ultraviolet polarized light using a circular mask to a liquid crystal cell manufactured in Example 4 of the present invention, wherein (a) is a photograph when the polarization direction and the transmission axis are parallel to each other. , (b) is a photograph when the polarization direction and transmission axis is 45 degrees,
FIG. 12 illustrates the liquid crystal display of FIG. 11. (a) is (B) is a photograph when the polarization direction and the transmission axis are parallel in the region irradiated with ultraviolet rays, (c) is a photograph when the polarization direction and the transmission axis are 45 degrees,
FIG. 13 is a liquid crystal display device manufactured after irradiation of ultraviolet polarized light using a circular mask to a liquid crystal cell manufactured in Example 5 of the present invention, wherein (a) is a photograph when the polarization direction and the transmission axis are parallel to each other. , (b) is a photograph when the polarization direction and transmission axis is 45 degrees,
FIG. 14 illustrates the liquid crystal display of FIG. 13. (a) is (B) is a photograph when the polarization direction and the transmission axis are parallel to each other in the directly irradiated region, (b) is a photograph when the polarization direction and the transmission axis are 45 degrees,
15 is a liquid crystal display device manufactured after irradiation of ultraviolet polarized light using a circular mask to a liquid crystal cell manufactured in Example 6 of the present invention, wherein (a) is a photograph when the polarization direction and the transmission axis are parallel to each other; , (b) is a photograph when the polarization direction and transmission axis is 45 degrees,
FIG. 16 illustrates the liquid crystal display of FIG. 15. (a) is (B) is a photograph when the polarization direction and the transmission axis are parallel in the region irradiated with ultraviolet rays, (c) is a photograph when the polarization direction and the transmission axis are 45 degrees,
17 is a liquid crystal cell prepared in Comparative Example 1 of the present invention, (a) is a photograph observed under the orthogonal polarizer before irradiation of ultraviolet polarization, (b) is a fine polarization micrograph of the liquid crystal device,
In Figure 18 is the liquid crystal display of FIG. 17, (a) is a photograph at the time of the polarization direction parallel to the transmission axis, (b) is a photograph at the time the polarization direction and the transmission axis of 45 degrees,
FIG. 19 is a polarization microscope result after heat treatment in the liquid crystal display of FIG. 17, wherein (a) and (c) are photographs when the polarization direction and transmission axis are parallel to each other, and (b) and (d) are the polarization direction and transmission When the axis is 45 degrees,
FIG. 20 is a polarization microscope result of unpolarized ultraviolet irradiation to a liquid crystal display device heat-treated in Comparative Example 2 of the present invention. (A) and (c) are photographs when the polarization direction and transmission axis are parallel to each other. And (d) are photographs when the polarization direction and the transmission axis are 45 degrees.

Hereinafter, the present invention will be described in detail.

The present invention is a liquid crystal composition for horizontal orientation induction containing one or more orientation-induced photopolymerizable monomer represented by Formula 1, wherein the orientation-induced photopolymerizable monomer is in situ photopolymerized by linearly polarized ultraviolet irradiation Provided is a liquid crystal composition for inducing horizontal alignment, which induces horizontal alignment of liquid crystals.

Formula 1

In Chemical Formula 1, C _A and C _B are each independently a cyclic group selected from aryl, heteroaryl, or a cycloalkyl group of C ₄ to C ₁₀ , and a linear rigid-core through a linking group X ( to form a rigid-core group, and in each cyclic group, one or more hydrogen atoms may be substituted or unsubstituted with an alkyl group or a halogen group of C ₁ to C ₄ ,

X is a linking group connecting C _A and C _B and is a single bond, an ester group selected from -O-CO- or -CO-O-, -O-, -CH _2- , -CH ₂ O-,-CF _2- , -CF ₂ O-,-CH ₂ CH _2- , -CH ₂ CH ₂ O-, -CF ₂ CF ₂ -One of the linking group selected from, except that a double bond, triple bond sensitive to light irradiation , Azo group (N = N), -CO-C = C- and -O-CO-C = C- excluding the linking group selected from the group,

n is an integer of 1 to 3, R ₁ , R ₂ are each independently

And _{(CH 2) m1 OOC-, -} R 1 = P 1 - (CH 2) m1 O-, P 1 - (CH 2) m1 -, P 1 - (CH 2) m1 COO- , or P ₁

And _{(CH 2) m2 OOC-, -} R 2 = P 2 - (CH 2) m2 O-, P 2 - (CH 2) m2 -, P 2 - (CH 2) m2 COO- or P ₂

m1 and m2 are the integers of 0-12 independently, and said P <_1> , P <_2> are each independently an acryl group, a methacryl group, an acrylamide group, or a methacryl amide group.

Orientation-induced photopolymerizable monomer represented by the general formula (1) of the present invention is a structure having a polymerizable group at a terminal thereof connected to a flexible rigid-core group and connected to a flexible alkyl group, provided that conventional photosensitive Reversible photosensitive functional groups of photochemical reactions in mesogen compounds include azo-benzene, cinnamoyl, chacon, coumarine, phenylene vinylene and phenylene It excludes phenylene acetylene functional groups.

Among the alignment guide type photopolymerizable monomers represented by Formula 1, the aryl groups in C _A and C _B include a phenyl group or a naphthyl group, and a heteroaryl group pyridine ), Pyrimidine and pyrazine groups, and cycloalkyl groups include cyclobutane groups (cyclobutane), cyclohexane groups (cyclohexane), bicyclic cyclohexane groups (bicyclic cyclohexane), bi It may include a cyclic cyclopentane group (bicyclic cyclopentane), and also heterocycloalkyl group (heterocycloalkyl) may include a tetrahydropyran group (diotraane, dioxane) (dioxane).

It is selected from the structurally rigid annular groups defined in C _A and C _B and forms a linear rigid-core group through the linker X.

The orientation-induced photopolymerizable monomer represented by Formula 1 of the present invention is composed of a linear rigid-core group and a terminal photopolymerizable group, and induces horizontal alignment of the liquid crystal by photopolymerization using ultraviolet linear polarization. Orientation-induced photopolymerizable monomer represented by the formula (1) can greatly improve the orientation stability for heat treatment or light treatment after the orientation induction by excluding photosensitive functional groups in the conventional photo-alignment induction additive.

Preferred examples of the orientation-induced photopolymerizable monomer are any one selected from the group consisting of the following compounds.

X and Y are independently a single bond, an ester group selected from -O-CO- or -CO-O-, -O-, -CH _2- , -CH ₂ O-, -CF _2- , -CF ₂ O-, -CH ₂ CH _2- , -CH ₂ CH ₂ O-, -CF ₂ CF ₂ -It is one linking group selected from,

R ₁ and R ₂ are each independently

And _{(CH 2) m1 OOC-, -} R 1 = P 1 - (CH 2) m1 O-, P 1 - (CH 2) m1 -, P 1 - (CH 2) m1 COO- , or P ₁

R ₂ = P _2- (CH ₂ ) _{m 2} O-, P _2- (CH ₂ ) _{m 2-} , P _2- (CH ₂ ) _{m 2} COO- or P _2- (CH ₂ ) _{m 2} OOC-,

M1 and m2 are each independently an integer of 0 to 12, and P ₁ and P ₂ are each independently an acryl group, methacryl group, acrylamide group, or methacrylamide group.

In Examples 1 to 6 of the present invention have been described while presenting a variety of orientation-induced photopolymerizable monomer by adjusting the length of the linking group having the compound structure, it will not be limited thereto.

As a result of analyzing the polarization micrographs before and after the linearly polarized ultraviolet light irradiation on the liquid crystal display device manufactured using the orientation-induced photopolymerizable monomer of the present invention, FIG. 1 shows that the alignment process was not performed before the linearly polarized ultraviolet light irradiation. In FIG. 2 , the liquid crystals are randomly arranged (random horizontal arrangement) with respect to the surface horizontal to the substrate, whereas in FIG. 2 , the liquid crystal layer in the region inside the circle directly irradiated after the linearly polarized ultraviolet irradiation is the polarization direction of the polarizer and the irradiation light under the orthogonal polarizer. Depending on the uniform brightness and darkness can be observed.

In particular, through FIG. 3 , (a) is While the ultraviolet rays are not irradiated, the liquid crystal molecules are randomly arranged, and (b) is a photograph when the polarization direction and the transmission axis are parallel in the directly irradiated region, and (c) is the polarization direction and transmission. As a photograph when the axis was 45 degrees, it was possible to confirm a uniform horizontal alignment state in which the directions of the liquid crystals were uniformly arranged in the direction perpendicular to the linearly polarized light.

Therefore, from the above results, in the region directly irradiated with linearly polarized ultraviolet light, the orientation-induced photopolymerizable monomer mixed with the liquid crystal when the liquid crystal layer is formed is photopolymerized by linearly polarized ultraviolet radiation to form a photopolymer layer on the inner surface of the liquid crystal display substrate. It can be confirmed that it forms a uniform horizontal orientation of the liquid crystal host.

Furthermore, FIG. 4 shows that the liquid crystal alignment state of the liquid crystal aligning state with respect to high temperature heat by heat treatment after the induction of orientation is maintained.

In addition, FIG. 5 shows that the heat-treated liquid crystal display device is further irradiated with polarized light or non-polarized ultraviolet light to evaluate the stability of the liquid crystal alignment state, and thus it is possible to confirm that the liquid crystal display maintains a uniform alignment state.

Therefore, the liquid crystal composition for induction of horizontal alignment containing one or more types of alignment-induced photopolymerizable monomers of the present invention is in situ by linearly polarized UV irradiation without a separate linear alignment film coating process and a linear alignment treatment process. In addition to inducing a uniform horizontal alignment of the liquid crystal, the characteristics of the device can be stably maintained even after the alignment induced heat treatment and the additional irradiation of ultraviolet rays after the heat treatment, and finally a liquid crystal display device can maintain a stable alignment state.

6 to 16 show the results of observing the polarization image of the liquid crystal display device manufactured by selecting each compound of the alignment-induced photopolymerizable monomer of the present invention and manufacturing each liquid crystal cell, and after the linearly polarized ultraviolet irradiation. In addition, it is possible to confirm a uniform horizontal alignment state in which the direction of the liquid crystal is uniaxially arranged in a direction perpendicular to the irradiated linearly polarized light. In this figure, the orthogonal arrow indicates the transmission direction of each orthogonal polarizer, and a single bidirectional arrow indicates the processing direction of the polarized ultraviolet light.

On the other hand, Figures 17 to 20 are each of the liquid crystal cell manufactured by using an orientation-induced photopolymerizable monomer containing a photosensitive functional group (cinnamate group or azo group), and after the linearly polarized ultraviolet irradiation of the liquid crystal display device As a result of observing the polarization image, the horizontal alignment of the liquid crystals was confirmed, but in the case of the liquid crystal display device heat-treated or light-treated after the alignment induction, the deterioration of the liquid crystal alignment is accelerated and thus it may not be maintained in a uniform alignment state.

From the above, the present invention is a first step of preparing a liquid crystal composition for induction of horizontal alignment consisting of a liquid crystal mixture containing at least one type of orientation-induced photopolymerizable monomer represented by the formula (1),

A second process of manufacturing a liquid crystal cell assembly by injecting the liquid crystal composition for horizontal alignment induction between a first substrate and a second substrate;

A horizontal alignment liquid crystal comprising a third process of inducing a horizontal alignment of liquid crystals by photopolymerization of the alignment-induced photopolymerizable monomer by irradiating in situ linearly polarized ultraviolet rays to the liquid crystal cell assembly to produce a liquid crystal display device A method of manufacturing a display device is provided.

In the first step, the liquid crystal composition for horizontal orientation induction is mixed with a conventional liquid crystal host used in a display, the alignment-induced photopolymerizable monomer represented by the formula (1), the total amount of at least one alignment-induced photopolymerizable monomer It is preferable to contain 0.01-5.0 weight% with respect to a host. At this time, when the orientation-induced photopolymerizable monomer is less than 0.01% by weight, the orientation-induced effect is insignificant, and when it exceeds 5.0% by weight, compatibility between components is poor, or the density of formation of orientation defects during light treatment is not preferable. .

In addition, in the second process, the gap between the first substrate and the second substrate is preferably maintained at 2 to 10 μm when the assembly is formed, and the injection process of the liquid crystal composition for horizontal alignment induction is performed at room temperature or horizontal orientation induction. It may also be carried out at an isotropic temperature of the liquid crystal composition for.

The third process may be preferably performed at an isotropic temperature of the liquid crystal composition for horizontal alignment, in which case it can be seen that a uniform horizontal alignment of the liquid crystal host is induced by cooling to room temperature after irradiation with linearly polarized ultraviolet. In the third step, by irradiating linearly polarized ultraviolet light, the orientation-induced photopolymerizable monomer is polymerized by the irradiation and adsorbed onto the inner surface of the upper substrate and the lower substrate, thereby naturally forming a thin polymer film on the surface of the substrate without physical or chemical external force. . Therefore, stable liquid crystal alignment force can be provided to the inner surface of a board | substrate only by irradiation of linearly polarized ultraviolet-ray, without performing the process of pre-coating an oriented film.

In the method of manufacturing the horizontal alignment liquid crystal display device of the present invention, after the three steps, the liquid crystal composition may be heat-treated to increase the uniformity of the liquid crystal alignment.

Further, after the heat treatment, the step of additionally irradiating linearly polarized or unpolarized ultraviolet rays at a temperature that is a liquid crystal phase of the liquid crystal composition for horizontal orientation induction may reduce the amount of residual monomer and increase the alignment force of the liquid crystal. .

From the above manufacturing method, the present invention provides a horizontal alignment liquid crystal display device. Specifically, the first substrate and the second substrate,

A photopolymer layer formed on the inner surface of the substrate while the orientation-induced photopolymerizable monomer contained in the liquid crystal composition for horizontal alignment injecting between the first substrate and the second substrate is photopolymerized by linearly polarized ultraviolet irradiation, and the formed photopolymer layer By the in situ ( in situ ) method comprising a liquid crystal layer induced the horizontal alignment of the liquid crystal,

The liquid crystal composition for horizontal alignment induction is characterized in that the liquid crystal mixture containing at least one orientation-induced photopolymerizable monomer represented by the formula (1).

According to the structural feature of the alignment type photopolymerizable monomer of the present invention, the horizontally aligned liquid crystal display device has an acrylic polymerizable group at a terminal thereof and is connected to a flexible alkyl group around a linear rigid-core group. The linearly polarized UV radiation induces a uniform horizontal alignment of the liquid crystal in an in situ manner.

In addition, the present invention is a reversible photosensitive functional group of the photochemical reaction in the rigid-core group constituting the orientation-induced photopolymerizable monomer, azo-benzene, cinnamoyl, chacon A structure that excludes chalcon, coumarine, phenylene vinylene, and phenylene acetylene functional groups provides a method for greatly improving the stability of induced orientation.

Therefore, the liquid crystal display device of the present invention can be stably applied to all liquid crystal drive information devices such as mobile phones, table PCs, notebook computers, TVs. In particular, the technique proposed in the present invention may be usefully used in the fabrication of high performance large sized and ultra high definition display devices that are difficult to apply the conventional alignment layer rubbing process.

Hereinafter, the present invention will be described in more detail with reference to Examples.

This embodiment is intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

Example 1 Fabrication of Liquid Crystal Display Device 1

1. Preparation process of orientation-induced photopolymerizable monomer

In the orientation-induced photopolymerizable monomer represented by Formula 1, C _A and C _B are phenyl groups, X forms a rigid-core group bonded by a single bond, and 4, 4 of the two phenyl groups Has a structure in which the acrylate group is linearly bonded to the position ', and linked with 0, 3, 6, or 12 flexible alkyloxy groups as a linking group to the terminal acrylate group, the following Chemical Formulas 1-1a to The compound represented by 1-1d was prepared.

Formula 1-1a

Yield ~ 95%, ¹ H NMR (400 MHz, DMSO-d ₆ ) (δ, ppm): 7.54 (4H, Ar-H), 7.18 (4H, Ar-H), 6.12-5.48 (m, 6H, Vinyl ).

Formula 1-1b

Yield ~ 90%, ¹ H NMR (400 MHz, DMSO-d ₆ / CDCl ₃ ) (δ, ppm): 7.52 (4H, Ar-H), 7.08 (4H, Ar-H), 6.12-5.45 (m, 6H, Vinyl), 4.35 (4H, -PhOCH ₂ ), 4.10 (4H, -COOCH ₂ ), 2.11 (4H, -CH ₂ ).

Formula 1-1c

Yield ~ 86%, ¹ H NMR (400 MHz, DMSO-d ₆ / CDCl ₃ ) (δ, ppm): 7.52 (4H, Ar-H), 7.08 (4H, Ar-H), 6.15-5.45 (m, 6H, Vinyl), 4.25 (4H, -PhOCH ₂ ), 3.95 (4H, -COOCH ₂ ), 1.85-1.32 (16H, -CH ₂ ).

Formula 1-1d

Yield ~ 67%, ¹ H NMR (400 MHz, DMSO-d ₆ / CDCl ₃ ) (δ, ppm): 7.52 (4H, Ar-H), 7.08 (4H, Ar-H), 6.25-5.55 (m, 6H, Vinyl), 4.18 (4H, -PhOCH ₂ ), 3.91 (4H, -COOCH ₂ ), 1.80-1.02 (40H, -CH ₂ ).

2. Liquid Crystal Cell Manufacturing Process

The first substrate on which no electrode was formed and the second substrate on which the pixel electrode and the common electrode were formed, respectively, were ultrasonically cleaned in distilled water using a cleaning agent, and then washed with acetone and isopropyl alcohol, respectively, and dried. In this case, after the first and second substrates are assembled to face each other without a separate alignment film coating and alignment treatment, the total weight of the liquid crystal host having positive dielectric anisotropy is represented by the following formulas: 1-1a to 1-1. A granulated body was prepared by injecting a liquid crystal composition for horizontal alignment induction containing 0.5 wt% of one compound selected from the compounds represented by 1d, mixing them uniformly.

The gap between the first substrate and the second substrate was maintained at 10 μm when the assembly was formed, and the injection process of the liquid crystal composition for horizontal alignment induction was performed at 90 ° C., which is an isotropic temperature of the liquid crystal composition for horizontal alignment induction.

After injecting the liquid crystal composition for horizontal orientation induction, the assembly was cooled at a rate of 5 ° C./minute, and the arrangement of liquid crystals was observed using a polarizing microscope.

3. In situ orientation guide process

In a heated state in 90 ℃ the isotropic phase temperature of a liquid crystal for inductively oriented horizontally above prepared assembly of the composition, by screen linearly polarized light to the ultraviolet ray generated from a metal halide lamp through cut linearly (with a wavelength of 365nm standard) to 3 mW / cm ² intensity And irradiated for 30 minutes in a direction perpendicular to the substrate surface to in situ linearly polarized ultraviolet light treatment to induce a uniform horizontal alignment of the liquid crystal. At this time, the light irradiation was applied so that light is irradiated only inside a circle having a diameter of about 1.5 cm by applying a circular mask, so that light is not directly irradiated to the liquid crystal composition in other regions.

Experimental Example 1 Polarization Microscope Analysis

In Example 1, the alignment-induced photopolymerizable monomers represented by Chemical Formulas 1-1a to 1-1d each independently induced uniform horizontal alignment of the liquid crystal through the light treatment process. Among them, an experimental example will be presented based on the embodiment using the orientation-induced photopolymerizable monomer represented by Formula 1-1a.

1. Polarization microscope analysis before irradiation of ultraviolet polarization

After injecting the liquid crystal composition for horizontal orientation induction into the liquid crystal cell preparation (Step 2) of Example 1, the assembly was cooled at a rate of 5 / min, and the alignment state of the liquid crystal was observed using a polarizing microscope.

1 is a liquid crystal cell of Example 1 prepared using an orientation-induced photopolymerizable monomer represented by Formula 1-1a, wherein (a) is a photograph observed under a quadrature polarizer before irradiation of ultraviolet polarization, and (b) Is a micro-polarization micrograph of the liquid crystal device, it was confirmed that the liquid crystal is randomly arranged (random horizontal arrangement) with respect to the surface horizontal to the substrate because no separate alignment treatment process was performed.

2. Polarization Microscope Analysis After Irradiation of Ultraviolet Polarization

After the light irradiation in the liquid crystal display device fabrication (step 3) of Example 1, after cooling the liquid crystal display assembly at room temperature at a rate of 5 ℃ / min, the alignment state of the liquid crystal was observed using a polarizing microscope.

2 is a liquid crystal display device manufactured by irradiating ultraviolet polarized light using a circular mask to the liquid crystal cell, wherein (a) is a photograph when the polarization direction and transmission axis are parallel to each other, and (b) is a polarization direction and transmission When the axis is 45 degrees, the liquid crystal layer in the region inside the circle where ultraviolet polarization is directly irradiated in the manufactured liquid crystal display device exhibits uniform light and dark states according to the polarization directions of the polarizer and the irradiated light under the orthogonal polarizer. It was.

Specifically, FIG. 3 shows the liquid crystal display device. (a) is In the region not irradiated with ultraviolet rays, the liquid crystal molecules were randomly arranged, (b) is a photograph when the polarization direction and the transmission axis are parallel to each other in the directly irradiated region, and (c) is the polarization direction and the transmission axis. As a photograph at this 45 degree | time, the uniform horizontal orientation state which the direction of the liquid crystal was uniformly arranged in the direction perpendicular | vertical to linear polarization was shown.

From the above results, in the region directly irradiated with ultraviolet polarization, the orientation-induced photopolymerizable monomer mixed with the liquid crystal during the formation of the liquid crystal layer is photopolymerized by linearly polarized ultraviolet radiation, thereby forming a photopolymer layer on the inner surface of the liquid crystal display substrate. It was confirmed that the liquid crystal host induced a uniform horizontal alignment.

3. Evaluation of stability through polarization microscope analysis after heat treatment

In order to evaluate the stability to high temperature heat of the liquid crystal alignment state of the prepared liquid crystal display device, the prepared liquid crystal display device was stored in an oven at 120 ° C. for 24 hours, and then cooled to room temperature. The results are shown in FIG. 4.

4 is the same as the results of FIG. 2 before heat treatment, and the results of (c) and (d) were also observed in the same manner as the horizontal alignment state of the liquid crystal identified in FIG. Therefore, it was confirmed that the liquid crystal alignment state before the heat treatment was maintained even after the heat treatment.

4. Analysis of Polarizing Microscope after Irradiation of Unpolarized UV Light after Heat Treatment

In order to evaluate the stability of polarized or unpolarized ultraviolet light in the liquid crystal alignment state of the heat-treated liquid crystal display device, the non-polarized ultraviolet light (wavelength of 365 nm) generated by the metal halide lamp is applied to the high temperature heat-treated liquid crystal display device. After irradiation for 2 hours at 3 mW / cm ² intensity, the arrangement of the liquid crystal is shown in Figure 5 using a polarizing microscope.

From the results of FIGS. 5A to 5D, it was confirmed that the liquid crystal maintained a uniform alignment state.

Example 2 Fabrication of Liquid Crystal Display Device 2

In the orientation-induced photopolymerizable monomer represented by Formula 1, a compound represented by Formulas 1-2a to 1-2d was prepared. The compound forms a rigid-core group in which three phenyl groups are bonded through a single bond, and has a structure in which an acrylate group is linearly bonded at 4 and 4 'positions of a terphenyl group. The terphenyl group has 0, 3, 6, or 12 flexible alkyloxy groups as a linking group, and has a structure connected to an acrylate group at the terminal group.

Formula 1-2a

Yield-91%, ¹ H NMR (400 MHz, DMSO-d ₆ ) (δ, ppm): 7.72 (4H, Ar-H), 7.28 (4H, Ar-H), 7.03 (4H, Ar-H), 6.25-5.50 (m, 6H, Vinyl)

Formula 1-2b

Yield-84%, ¹ H NMR (400 MHz, DMSO-d ₆ ) (δ, ppm): 7.82 (4H, Ar-H), 7.28 (4H, Ar-H), 7.13 (4H, Ar-H), 6.15-5.45 (m, 6H, Vinyl), 4.35 (4H, -PhOCH ₂ ), 4.12 (4H, -COOCH ₂ ), 2.15 (4H, -CH ₂ ).

Formula 1-2c

Yield ^{~ 64%, 1 H NMR (} 400 MHz, DMSO-d 6) (δ, ppm): 7.82 (4H, Ar-H), 7.28 (4H, Ar-H), 7.13 (4H, Ar-H), 6.15-5.45 (m, 6H, Vinyl), 4.09 (4H, -PhOCH ₂ ), 3.91 (4H, -COOCH ₂ ), 1.95-1.32 (16H, -CH ₂ ).

Formula 1-2d

Yield-61%, ¹ H NMR (400 MHz, DMSO-d ₆ ) (δ, ppm): 7.82 (4H, Ar-H), 7.28 (4H, Ar-H), 7.13 (4H, Ar-H), 6.15-5.45 (m, 6H, Vinyl), 4.09 (4H, -PhOCH ₂ ), 3.91 (4H, -COOCH ₂ ), 1.95-1.02 (40H, -CH ₂ ).

The first substrate comprises a liquid crystal composition for induction of horizontal alignment containing 0.3% by weight, based on the total weight of the liquid crystal host having one of the compounds selected from the compounds represented by Chemical Formulas 1-2a to 1-2d, having a positive dielectric anisotropy. The liquid crystal display device was fabricated by performing the same steps 2 and 3 as in Example 1, except that the liquid crystal cell was manufactured by injecting between the second substrates.

Experimental Example 2 Polarizing Microscope Analysis

In Example 1, the orientation-induced photopolymerizable monomers represented by Chemical Formulas 1-2a to 1-2d independently induced uniform horizontal alignment of the liquid crystal through the light treatment process. The polarization microscope analysis results will be presented based on the examples using the orientation-induced photopolymerizable monomer represented by Formula 1-2c.

FIG. 6 is a liquid crystal display device manufactured after irradiation of ultraviolet polarized light using a circular mask in a liquid crystal cell manufactured using an orientation-induced photopolymerizable monomer represented by Chemical Formula 1-2c of the present invention. It is a photograph when a polarization direction and a transmission axis are parallel, (b) is a photograph when a polarization direction and a transmission axis are 45 degrees. As a result, the liquid crystal layer exhibited uniform light and dark states according to the polarization directions of the polarizer and the irradiation light under the orthogonal polarizer.

7 is a cross-sectional view of the LCD of FIG. 6. (a) is In the region (a) where no direct ultraviolet rays were irradiated, the liquid crystal molecules were randomly arranged, (b) is a photograph when the polarization direction and the transmission axis were parallel in the directly irradiated region, and (c) is polarization. The photograph was obtained when the direction and the transmission axis were 45 degrees, showing a uniform horizontal alignment state in which the directions of the liquid crystals were uniaxially arranged in a direction perpendicular to the irradiated linearly polarized light.

Example 3 Fabrication of Liquid Crystal Display Device 3

In the orientation-induced photopolymerizable monomer represented by Formula 1, compounds represented by the following Formulas 1-3a to 1-3d were prepared. The compound has a structure in which three phenyl groups form a rigid-core group bonded through an ester (-COO-) group and linearly bond an acrylate group at 4 and 4 'positions of phenyl groups at both ends. The central phenyl group has or does not have a methyl substituent, and the phenyl group at both ends is connected to an acrylate group by a linking group having 0, 3, 6, or 12 flexible alkyloxy groups.

Formula 1-3a

Yield ~ 80%, ¹ H NMR (400 MHz, CDCl ₃ ) (δ, ppm): 8.18 & 8.19 (dd, 4H, Ar-H), 7.95 (m, 3H, Ar-H), 6.95 (dd, 4H , Ar-H), 6.11-5.45 (m, 6H, Vinyl), 2.15 (s, 3H, PhCH ₃ ).

Formula 1-3b

Yield ~ 60%, ¹ H NMR (400 MHz, CDCl ₃ ) (δ, ppm): 8.18 & 8.19 (dd, 4H, Ar-H), 7.95 (m, 3H, Ar-H), 6.95 (dd, 4H , Ar-H), 6.5-5.8 (m, 6H, Vinyl), 4.31 (t, 4H, -COOCH ₂ ), 4.09 (t, 4H, PhOCH ₂ ), 2.23 (s, 3H, PhCH ₃ ), 2.1 ( m, 4H, -CH ₂ ).

Formula 1-3c

Yield ~ 65%, ¹ H NMR (400 MHz, CDCl ₃ ) (δ, ppm): 8.18 & 8.19 (dd, 4H, Ar-H), 7.95 (m, 3H, Ar-H), 6.95 (dd, 4H , Ar-H), 6.5-5.8 (m, 6H, Vinyl), 4.20 (t, 4H, -COOCH ₂ ), 4.05 (t, 4H, PhOCH ₂ ), 2.23 (s, 3H, PhCH ₃ ), 1.9- 1.4 (m, 16H, -CH ₂ ).

Formula 1-3d

Yield ~ 68%, ¹ H NMR (400 MHz, CDCl ₃ ) (δ, ppm): 8.18 (d, 4H, Ar-H), 7.25 (s, 4H, Ar-H), 7.0 (d, 4H, Ar -H), 6.5-5.8 (m, 6H, Vinyl), 4.22 (t, 4H, -COOCH ₂ ), 4.05 (t, 4H, PhOCH ₂ ), 1.9-1.3 (m, 16H, -CH ₂ ).

The first substrate comprises a liquid crystal composition for induction of horizontal alignment, in which one compound selected from the compounds represented by Chemical Formulas 1-3a to 1-3d is contained in an amount of 0.5% by weight, based on the total weight of the liquid crystal host having positive dielectric anisotropy. The liquid crystal display device was fabricated by performing the same steps 2 and 3 as in Example 1, except that the liquid crystal cell was manufactured by injecting between the second substrates.

Experimental Example 3 Polarization Microscope Analysis

In Example 1, the alignment-induced photopolymerizable monomers represented by Chemical Formulas 1-3a to 1-3d each independently induced uniform horizontal alignment of the liquid crystal through the light treatment process. Among them, the polarization microscope analysis results will be presented based on the examples using the orientation-induced photopolymerizable monomer represented by Formula 1-3b.

8 is a liquid crystal display device manufactured by irradiating ultraviolet polarized light using a circular mask to a liquid crystal cell manufactured using an orientation-induced photopolymerizable monomer represented by Chemical Formula 1-3b of the present invention. (B) is a photograph when the polarization direction and the transmission axis is 45 degrees, the liquid crystal layer is uniform light and dark according to the polarization direction of the polarizer and the irradiation light under the orthogonal polarizer. Status is shown.

9 is a result of observing the alignment state of the microscopic liquid crystal with a polarization microscope, (a) (B) is a photograph when the polarization direction and the transmission axis are parallel in the region irradiated with ultraviolet rays, and (c) shows a photograph when the polarization direction and the transmission axis are 45 degrees. As a result, in the region (a) where the linearly polarized ultraviolet light was not directly irradiated, the liquid crystal molecules were randomly arranged. In the region where the linearly polarized ultraviolet light was directly irradiated, the liquid crystal molecules were uniformly arranged in a direction perpendicular to the irradiated linearly polarized light. The horizontal orientation is shown.

In addition, FIG. 10 is a polarization microscope result for evaluating the stability to high temperature heat in the liquid crystal alignment state after the heat treatment to the liquid crystal display device, (a) and (c) is a photograph when the polarization direction and the transmission axis is parallel (B) and (d) are photographs when the polarization direction and the transmission axis are 45 degrees, showing that the alignment state of the liquid crystal is maintained even after heat and light treatment.

Example 4 Fabrication of Liquid Crystal Display Device 4

In the orientation-induced photopolymerizable monomer represented by Formula 1, compounds represented by the following Formulas 1-4a to 1-4d were prepared. The compound has a structure in which two phenyl groups form a rigid-core group in which an ester (-COO-) group is bonded, and a methacrylate group is linearly bonded at 4, 4 'positions at the terminal of the phenyl group. In this case, the phenyl group is a structure connected to a photopolymerizable methacrylate group by using a linkage group having 0, 3, 6, or 12 flexible alkyloxy groups.

Formula 1-4a

Yield-63%, ¹ H NMR (400 MHz, CDCl ₃ ) (δ, ppm): 8.25 (2H, Ar-H), 7.58-7.21 (6H, Ar-H), 6.52 (2H, = CH ₂ ), _{6.04 (2H, = CH 2)} , 2.01 (6H, -CH 3).

Formula 1-4b

Yield-52%, ¹ H NMR (400 MHz, CDCl ₃ ) (δ, ppm): 8.2 (2H, Ar-H), 7.28-7.01 (6H, Ar-H), 6.12 (2H, = CH ₂ ), 5.54 (2H, = CH ₂ ), 4.32 (4H, -CH ₂ -OPh), 4.02 (4H, -COOCH ₂ ), 2.18 (4H, -CH ₂ ), 2.01 (6H, -CH ₃ ).

Formula 1-4c

Yield-47%, ¹ H NMR (400 MHz, CDCl ₃ ) (δ, ppm): 8.2 (2H, Ar-H), 7.25-7.00 (6H, Ar-H), 6.02 (2H, = CH ₂ ), _{5.56 (2H, = CH 2)} , 4.1 (4H, -CH 2 -OPh), 3.92 (4H, -COOCH 2), 2.05 (6H, -CH 3), 1.8-1.05 (16H, -CH 2).

Formula 1-4d

Yield-30%, ¹ H NMR (400 MHz, CDCl ₃ ) (δ, ppm): 8.18 (2H, Ar-H), 7.26-7.05 (6H, Ar-H), 6.12 (2H, = CH ₂ ), 5.54 (2H, = CH ₂ ), 4.06 (4H, -CH ₂ -OPh), 3.90 (4H, -COOCH ₂ ), 2.01 (6H, -CH ₃ ), 1.8-0.85 (40H, -CH ₂ ).

The first substrate comprises a liquid crystal composition for horizontal orientation induction, in which one compound selected from the compounds represented by Chemical Formulas 1-4a to 1-4d is 1.0% by weight based on the total weight of the liquid crystal host having positive dielectric anisotropy. The liquid crystal display device was fabricated by performing the same steps 2 and 3 as in Example 1, except that the liquid crystal cell was manufactured by injecting between the second substrates. At this time, the gap between the first substrate and the second substrate was maintained at 6.0 μm.

Experimental Example 4 Polarization Microscope Analysis

In Example 1, the orientation-induced photopolymerizable monomers represented by Chemical Formulas 1-4a to 1-4d independently induced uniform horizontal alignment of the liquid crystals through the light treatment process. Among them, the results of polarization microscope analysis will be presented based on the examples using the orientation-induced photopolymerizable monomer represented by Formula 1-4b.

11 is a liquid crystal display device manufactured by using an orientation-induced photopolymerizable monomer represented by Chemical Formula 1-4b of the present invention after irradiation of ultraviolet polarized light using a circular mask, wherein ultraviolet polarized light is directly In the region inside the irradiated circle, the liquid crystal layer exhibits uniform light and dark states according to the polarization directions of the polarizer and the irradiation light under the orthogonal polarizer, and in other regions, the liquid crystal layer maintains a random arrangement.

Figure 12 is a result of observation of the alignment of the microscopic liquid crystal by a polarization microscope, is (a) (B) shows the picture when the polarization direction and the transmission axis are parallel in the directly irradiated area, and (b) shows the picture when the polarization direction and the transmission axis are 45 degrees. The direction of the liquid crystal is uniform in the direction perpendicular to the irradiated linear polarization. The uniformly aligned state is shown.

Furthermore, it was shown that the alignment state of the liquid crystal is maintained uniformly even after the heat treatment at 120 ° C. and unpolarized ultraviolet ray irradiation to the completed liquid crystal display device [not shown].

Example 5 Fabrication of Liquid Crystal Display 5

In the orientation-induced photopolymerizable monomer represented by Formula 1, 1.0% by weight of the liquid crystal composition containing 1.0 wt% of the compound represented by the following Formula 1-5 to the total weight of the liquid crystal host having positive dielectric anisotropy is prepared. A liquid crystal display device was manufactured by performing the same steps 2 and 3 as in Example 1, except that the liquid crystal cell was manufactured by injecting the first substrate and the second substrate. At this time, the gap between the first substrate and the second substrate was maintained at 6.0 μm.

The compound represented by Formula 1-5 forms a rigid-core group in which two phenyl groups are bonded via a single bond, a methoxy group at the end of the phenyl group, and a flexible alkyloxy group having 6 carbon atoms at the other end thereof. It is a structure connected with the methacrylate group by the coupling group.

Formula 1-5

Yield ~ 80%, ¹ H NMR (400 MHz, CDCl ₃ ) (δ, ppm): 7.46 (d, 4H, Ar-H), 6.92 (d, 4H, Ar-H), 6.10 (d, 1H, = CH ₂ ), 5.55 (d, 1H, = CH ₂ ), 4.16 (m, 2H, -OCH _2- ), 3.99 (m, 2H, -OCH _2- ), 3.85 (t, 3H, -CH ₃ ), 2.01 (s, 3H, -CH ₃ ), 1.81 (m, 2H, -CH _2- ), 1.72 (m, 2H, -CH _2- ), 1.57-1.41 (m, 4H, -CH _2- ).

Experimental Example 5 Polarization Microscope Analysis

In Example 1, the liquid crystal cell prepared by using the orientation-induced photopolymerizable monomer represented by Chemical Formula 1-5 and the liquid crystal display device prepared by linearly polarized ultraviolet irradiation were analyzed by polarization microscope.

13 is according to the liquid crystal cell produced by using the oriented inductive photopolymerizable monomer represented by the formula 1-5 according to the present invention, after the polarization of ultraviolet light using a circular mask irradiation produced a liquid crystal display device, (a) and In the region inside the circle irradiated with ultraviolet polarization directly through (b), the liquid crystal layer exhibits uniform light and dark states according to the polarization directions of the polarizer and the irradiated light under the orthogonal polarizer, and maintains a random arrangement in other regions. You can check it.

14 is a result of observing the alignment state of the microscopic liquid crystal with a polarization microscope, (a) (B) shows the picture when the polarization direction and the transmission axis are parallel in the directly irradiated area, and (b) shows the picture when the polarization direction and the transmission axis are 45 degrees. The direction of the liquid crystal is uniform in the direction perpendicular to the irradiated linearly polarized light. The uniformly aligned state is shown.

Furthermore, it was shown that the alignment state of the liquid crystal is maintained uniformly even after the heat treatment at 120 ° C. and unpolarized ultraviolet ray irradiation to the completed liquid crystal display device [not shown].

Example 6 Fabrication of Liquid Crystal Display 6

In the orientation-induced photopolymerizable monomer represented by Formula 1, 1.0% by weight of a liquid crystal composition containing 1.0 wt% of the compound represented by Formula 1-6 to the total weight of the liquid crystal host having positive dielectric anisotropy is prepared. A liquid crystal display device was manufactured by performing the same steps 2 and 3 as in Example 1, except that the liquid crystal cell was manufactured by injecting the first substrate and the second substrate. At this time, the gap between the first substrate and the second substrate was maintained at 6.0 μm.

The compound represented by Formula 1-6 forms a rigid-core group in which two phenyl groups are bonded through an ester group, and at one end of each phenyl group, a methoxy group and the other end Has a structure in which a C6 flexible alkyloxy group is linked to a methacrylate group.

Formula 1-6

Yield ~ 85%, ¹ H NMR (400 MHz, DMSO-d ₆ ) (δ, ppm): 8.50-6.99 (m, 8H, Ar-H), 6.05 (d, 1H, = CH ₂ ), 5.50 (d , 1H, = CH ₂ ), 4.03 (m, 2H, -OCH _2- ), 3.95 (m, 2H, -OCH _2- ), 3.23 (t, 3H, -CH ₃ ), 2.21 (s, 3H,- CH ₃ ), 1.93-0.50 (m, 8H, -CH _2- ).

Experimental Example 6 Polarizing Microscope Analysis

In Example 1, the liquid crystal cell manufactured by using the orientation-induced photopolymerizable monomer represented by Chemical Formula 1-6 and the liquid crystal display device prepared by linearly polarized ultraviolet irradiation were analyzed by polarization microscope.

FIG. 15 is a liquid crystal display device manufactured after irradiation of ultraviolet polarized light using a circular mask in a liquid crystal cell manufactured using an orientation-induced photopolymerizable monomer represented by Chemical Formula 1-6 of the present invention. (B) is a photograph when the polarization direction and the transmission axis are parallel to each other, (b) is a photograph when the polarization direction and the transmission axis is 45 degrees, the liquid crystal layer in the region inside the circle irradiated with ultraviolet polarization directly under the orthogonal polarizer According to the polarization direction of the irradiation light, uniform light and dark conditions were shown.

FIG. 16 illustrates the liquid crystal display of FIG. 15. (a) is In the region not irradiated with ultraviolet rays, the liquid crystal molecules are randomly arranged, (b) is a photograph when the polarization direction and the transmission axis are parallel in the directly irradiated region, and (c) is the polarization direction and the transmission axis The photograph at 45 degrees showed a uniform horizontal alignment state in which the directions of the liquid crystals were uniformly arranged in the direction perpendicular to the irradiated linearly polarized light in the region directly irradiated with the linearly polarized ultraviolet light.

In addition, the produced liquid crystal display device was maintained for 24 hours in an oven of 120 and then cooled to room temperature to maintain a uniform alignment state even if the alignment state of the liquid crystal was observed. Further, it was confirmed that the liquid crystal display maintains a uniform alignment state of the liquid crystal even after irradiating non-polarized ultraviolet light (based on a wavelength of 365 nm) generated at a metal halide lamp with 3 mW / cm ² intensity for 2 hours [not shown].

Comparative Example 1

A liquid crystal cell is prepared by injecting a liquid crystal composition for horizontal alignment inducing 1.0 wt% based on the total weight of a liquid crystal host having positive dielectric anisotropy of the photosensitive compound represented by Formula 2 between the first substrate and the second substrate. Except that, the following two steps and three steps were carried out in the same manner as in Example 1 to produce a liquid crystal display device. At this time, the gap between the first substrate and the second substrate was maintained at 6.0 mu m.

The compound represented by Formula 2 is a structure in which a cyclohexyl group forms a rigid-core group connected to a photosensitive cinnamate group, and one photopolymerizable acrylic group is linked to a cyclohexyl group through a flexible space group. .

Formula 2

Experimental Example 7 Polarization Microscope Analysis

1. Polarization microscope analysis before irradiation of ultraviolet polarization

After injecting the liquid crystal composition for horizontal alignment in the liquid crystal cell preparation (2 step) of Comparative Example 1, the assembly was cooled at a rate of 5 ° C./min, and the alignment state of the liquid crystal was observed using a polarizing microscope.

17 is a liquid crystal cell prepared in Comparative Example 1, (a) is a photograph observed under the orthogonal polarizer before irradiation of ultraviolet polarization, (b) is a fine polarization micrograph of the liquid crystal device, another alignment treatment step Since the liquid crystal was not implemented, it was confirmed that the liquid crystals were randomly arranged (random horizontal arrangement) with respect to the surface horizontal to the substrate.

2. Polarization Microscope Analysis After Irradiation of Ultraviolet Polarization

After fabricating the liquid crystal display of Comparative Example 1 (step 3), after cooling the light, the liquid crystal display assembly was cooled to room temperature at a rate of 5 ° C./minute, and then the arrangement of the liquid crystals was observed using a polarizing microscope.

FIG. 18 is a liquid crystal display device manufactured after irradiation of ultraviolet polarization using a circular mask on a liquid crystal cell prepared in Comparative Example 1, wherein (a) is a photograph when the polarization direction and transmission axis are parallel to each other, and (b) Is a photograph when the polarization direction and the transmission axis are 45 degrees. In the region inside the circle irradiated with ultraviolet polarization, the liquid crystal layer exhibited light and dark states according to the polarization directions of the polarizer and the irradiation light under the orthogonal polarizer.

3. Evaluation of stability through polarization microscope analysis after heat treatment

In order to evaluate the stability to high temperature heat of the liquid crystal alignment state of the liquid crystal display device prepared in Comparative Example 1, the liquid crystal display device was stored in an oven at 120 ℃ for 24 hours and then cooled to room temperature, the arrangement state of the liquid crystal Was observed.

19 is a polarization microscope result after heat treatment to the liquid crystal display device, (a) and (c) is a photograph when the polarization direction and the transmission axis is parallel, (b) and (d) is the polarization direction and the transmission axis As a photograph at 45 degrees, deterioration of the alignment state of the liquid crystal could be observed rapidly. In addition, as a result of observing the liquid crystal alignment state after irradiating the non-polarized ultraviolet light generated by the metal halide lamp to the liquid crystal display device manufactured in Comparative Example 1, deterioration of the liquid crystal alignment was accelerated and it was not possible to maintain a uniform alignment state.

Comparative Example 2

A liquid crystal composition for injecting a horizontal alignment containing 0.5% by weight of the compound including the photosensitive azo group represented by the formula (3) based on the total weight of the liquid crystal host having positive dielectric anisotropy is injected between the first substrate and the second substrate. Except for manufacturing a cell, the following two steps and three steps were carried out in the same manner as in Example 1 to produce a liquid crystal display device. At this time, the gap between the first substrate and the second substrate was maintained at 10.0 μm.

The compound represented by Formula 3 forms a rigid-core group in which three phenyl groups are linearly connected to two azo groups, and two photopolymerizable methacryl groups are linear to the phenyl groups at both ends through a flexible space group. It is a structure connected by.

Formula 3

Experimental Example 8 Polarization Microscope Analysis

In the liquid crystal display device manufactured by irradiating ultraviolet polarized light using a circular mask to the liquid crystal cell manufactured in Comparative Example 2, the polarization direction of the polarizer and the irradiated light under the orthogonal polarizer in the region inside the circle where ultraviolet polarization was directly irradiated. According to the uniform light and dark state was shown [not shown].

However, after the heat treatment in the liquid crystal alignment state of the liquid crystal display device manufactured in Comparative Example 2, the liquid crystal alignment after irradiating non-polarized ultraviolet light or visible light generated by the metal halide lamp for 30 minutes at 1 mW / cm ² intensity (365 nm standard) The result of observing a state is shown in FIG .

As a result, as confirmed in FIGS. 20A to 20D, after the ultraviolet treatment, the alignment state of the liquid crystal deteriorated, and thus, it was not possible to maintain a uniform alignment state.

As described above, the present invention excludes a photosensitive functional group for the conventional photo-alignment, and has a polymerizable group at its terminal with a linear rigid-core group connected to a flexible alkyl group. Provided was a liquid crystal composition for inducing horizontal alignment containing one or more types of alignment-induced photopolymerizable monomers.

The orientation-induced photopolymerizable monomer contained in the liquid crystal composition for horizontal orientation induction is photopolymerized by linearly polarized ultraviolet radiation to form a photopolymer layer on the inner surface of the liquid crystal display device substrate, thereby inducing a uniform horizontal orientation of the liquid crystal host. A liquid crystal display device including the liquid crystal layer is provided.

The liquid crystal composition for induction of horizontal alignment containing the orientation-induced photopolymerizable monomer of the present invention is manufactured in a liquid crystal device without a separate linear alignment film coating process and a linear alignment treatment process, and then in situ method by linearly polarized ultraviolet radiation. The present invention provides a liquid crystal display device which not only induces horizontal alignment of liquid crystals, but also maintains orientation stability in heat treatment after alignment induction and further irradiation of ultraviolet rays after the heat treatment.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications belong to the appended claims.

Claims (8)

It is a liquid crystal composition for induction of horizontal alignment containing at least one type of orientation-induced photopolymerizable monomer represented by Formula 1,
Horizontal alignment to induce photo-polymerization of the alignment-induced photopolymerizable monomer in situ and induce horizontal alignment of liquid crystals without linearly processed ultraviolet light at the isotropic temperature of the liquid crystal composition for horizontal alignment induction. Induction liquid crystal composition:
Formula 1

In Chemical Formula 1, C _A and C _B are each independently a rigid-core group consisting of a cyclic group selected from C ₄ to C ₁₀ cycloalkyl groups, which may or may not include aryl, heteroaryl, or hetero elements. One or more hydrogen atoms in each cyclic group may be substituted or unsubstituted with an alkyl group or a halogen group of C ₁ to C ₄ ,
X is a linking group connecting C _A and C _B and is a single bond, an ester group selected from -O-CO- or -CO-O-, -O-, -CH _2- , -CH ₂ O-, -CF _2- , -CF ₂ O-, -CH ₂ CH _2- , -CH ₂ CH ₂ O-, -CF ₂ CF ₂ -It is one linking group selected from, provided that a double bond, triple bond sensitive to light irradiation , Azo group (N = N), -CO-C = C- and -O-CO-C = C- excluding the linking group selected from the group,
n is an integer from 1 to 3,
R ₁ and R ₂ are each independently
_{R 1 = P 1 - (CH} 2) m1 O-, P 1 - (CH 2) m1 -, P 1 - (CH 2) m1 COO- , or _{P 1 - (CH 2) m1} OOC- and
R ₂ = P _2- (CH ₂ ) _{m 2} O-, P _2- (CH ₂ ) _{m 2-} , P _2- (CH ₂ ) _{m 2} COO- or P _2- (CH ₂ ) _{m 2} OOC-
m1 and m2 are the integers of 0-12 independently, and said P <_1> , P <_2> are each independently an acryl group, a methacryl group, an acrylamide group, or a methacrylamide group. The liquid crystal composition of claim 1, wherein the alignment-induced photopolymerizable monomer is selected from the group consisting of the following compounds:

X and Y are independently a single bond, an ester group selected from -O-CO- or -CO-O-, -O-, -CH _2- , -CH ₂ O-, -CF _2- , -CF ₂ O-, -CH ₂ CH _2- , -CH ₂ CH ₂ O-, -CF ₂ CF ₂ -It is one linking group selected from,
R ₁ and R ₂ are each independently
And _{(CH 2) m1 OOC-, -} R 1 = P 1 - (CH 2) m1 O-, P 1 - (CH 2) m1 -, P 1 - (CH 2) m1 COO- , or P ₁
R ₂ = P _2- (CH ₂ ) _{m 2} O-, P _2- (CH ₂ ) _{m 2-} , P _2- (CH ₂ ) _{m 2} COO- or P _2- (CH ₂ ) _{m 2} OOC-,
M1 and m2 are each independently an integer of 0 to 12, and P ₁ and P ₂ are each independently an acrylic group, a methacryl group, an acrylamide group, or a methacrylamide group. A first step of preparing a liquid crystal composition for induction of horizontal alignment consisting of a liquid crystal mixture containing at least one orientation-induced photopolymerizable monomer represented by Formula 1,
A second process of manufacturing a liquid crystal cell assembly by injecting the liquid crystal composition for horizontal alignment induction between a first substrate and a second substrate;
Producing a liquid crystal display device by inducing a horizontal alignment of the liquid crystal by photopolymerization of the alignment-induced photopolymerizable monomer by irradiating in situ linearly polarized ultraviolet rays to the liquid crystal cell assembly at an isotropic temperature of the liquid crystal composition for horizontal alignment. A manufacturing method of a horizontal alignment liquid crystal display device comprising the third step of:
Formula 1

In the above formula, C _A , C _B , X, n, R ₁ , R ₂ are as defined in claim 1. 4. The method of claim 3, wherein the total amount of at least one alignment guide type photopolymerizable monomer in the first step is 0.01 to 5.0 wt% based on the liquid crystal host. delete The liquid crystal composition according to claim 3, wherein the liquid crystal composition in which the horizontal alignment of the liquid crystal is induced after the three steps is heat-treated or further irradiated with linearly or unpolarized ultraviolet light at the liquid crystal phase temperature of the liquid crystal composition for horizontal alignment after the heat treatment. A method of manufacturing a horizontal alignment liquid crystal display device. A first substrate and a second substrate,
A liquid crystal cell assembly manufactured by injecting a liquid crystal composition for induction of horizontal alignment containing at least one alignment guide type photopolymerizable monomer represented by Formula 1 between the first substrate and the second substrate;
The linearly polarized light wherein the alignment inductive photopolymerizable monomers by ultraviolet radiation are photopolymerized in situ (in situ) photo-polymerization layer on the inner surface of the substrate performed in the isotropic phase temperature of a liquid crystal cell assembly of the horizontally oriented induce liquid crystal composition for forming a Become,
A horizontal alignment type liquid crystal display device including a liquid crystal layer induced in a horizontal alignment process during the formation of the photopolymer layer:
Formula 1

In the above formula, C _A , C _B , X, n, R ₁ , R ₂ are as defined in claim 1. The horizontal alignment liquid crystal display device according to claim 7, wherein the liquid crystal composition for horizontal alignment induction is photopolymerized by containing a total amount of at least one orientation-inducing photopolymerizable monomer in an amount of 0.01 to 5.0 wt% based on the liquid crystal host.

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