KR20160031942A - Liquid crystal display device and method of manufacturing the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device forming a high-quality image with reduced texture and improved transmittance, and a manufacturing method thereof. The liquid crystal display device includes: a first substrate; a second substrate disposed to face the first substrate; a liquid crystal layer disposed between the first substrate and the second substrate, and comprising multiple liquid crystal molecules; and a self-alignment layer which is formed between the first substrate and the the liquid crystal layer, and includes a vertical alignment additive having a molecular structure in which a hydrophilic group is formed at one end of a core molecule, wherein the hydrophilic group faces a surface of the first substrate and a major axis of the core molecule is arranged at an angle smaller than 90 degrees with respect to the surface of the first substrate.

Description

[0001] The present invention relates to a liquid crystal display device and a manufacturing method thereof,

Embodiments of the present invention relate to a liquid crystal display and a method of manufacturing the same.

2. Description of the Related Art A liquid crystal display device is one of the most widely used flat panel display devices and includes two substrates having a field generating electrode such as a pixel electrode and a common electrode and a liquid crystal layer interposed therebetween. The liquid crystal display displays an image by applying a voltage to the electric field generating electrode to generate an electric field in the liquid crystal layer, thereby determining the direction of the liquid crystal molecules in the liquid crystal layer and controlling the polarization of the incident light.

Among liquid crystal display devices, there are a vertically aligned mode liquid crystal display device for driving liquid crystal using an electric field formed in the vertical direction of the substrate, an in-plane switching mode liquid crystal display device using a horizontal electric field parallel to the substrate There is a device.

The vertical alignment type liquid crystal display device has an advantage of excellent contrast ratio. In addition, in order to secure a wide viewing angle and increase the aperture ratio, a design method is adopted in which the liquid crystal layer region corresponding to one pixel is divided into a plurality of domains and liquid crystal molecules in the respective domains have different pretilt angles .

In recent years, the demand for a curved display device is increasing. In a bending process for forming a curved surface, the degree of warping of the upper and lower substrates is different, and the pretilt angle of the liquid crystal molecules misalignment may occur. This misalignment causes unstable texture.

Embodiments of the present invention provide a liquid crystal display device in which texture generation due to misalignment can be reduced when the embodiments of the present invention are applied to a curved panel.

According to an aspect of the present invention, there is provided a liquid crystal display comprising: a first substrate; A second substrate facing the first substrate; A liquid crystal layer disposed between the first substrate and the second substrate, the liquid crystal layer comprising a plurality of liquid crystal molecules; And a vertical alignment additive which is formed between the first substrate and the liquid crystal layer and has a molecular structure in which a hydrophilic group is formed at one end of the core molecule, wherein the hydrophilic group faces the first substrate surface, And a long axis of the self-alignment layer is arranged at an angle of less than 90 degrees with respect to the first substrate surface.

A polymerized group may be further formed at the other end of the core molecule.

The core molecule may be composed of a biphenyl of mesogenic unit, or a plurality of benzene, or a cyclohexane ring.

An alignment layer made of a vertical alignment material may be further formed between the second substrate and the liquid crystal layer.

The difference between the angle formed by the long axis of the liquid crystal molecules contacting the self-aligned layer with the first substrate surface and the long axis of the liquid crystal molecules contacting the alignment layer with the second substrate surface may be greater than 0.5 degrees.

The angle formed by the major axis of the liquid crystal molecules contacting the self-aligned layer with the first substrate surface may be greater than 85 ° and less than 89.5 °.

The surface on the first substrate that contacts the self-aligned layer may be in a hydrophilic treated state.

A silicon nitride layer may be further formed between the first substrate and the self-aligned layer.

A color filter may be formed on one of the first substrate and the second substrate, and a TFT array layer may be formed on the other substrate.

Alternatively, a color filter and a TFT array layer may be formed on either the first substrate or the second substrate.

The liquid crystal display device may be a liquid crystal display device in which the first substrate and the second substrate are bent so that a curved display surface is formed.

According to another aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, comprising: preparing a first substrate and a second substrate, each having a common electrode and a pixel electrode; Mixing an additive comprising a plurality of molecules in which a hydrophilic group is formed at one end of a core molecule with a plurality of liquid crystal molecules to form a liquid crystal mixture; Performing hydrophilic treatment on any one of the first substrate and the second substrate; Disposing the liquid crystal mixture between the first substrate and the second substrate, and performing electric field exposure.

A polymerized group may be further formed at the other end of the core molecule.

The content of the additive contained in the liquid crystal mixture may be 0.001% to 0.5%.

The liquid crystal mixture may further include an alkenyl single or alkoxy single.

The hydrophilic treatment may be performed such that the contact angle of the substrate with respect to the distilled water is 70 ° or less.

The hydrophilizing step may include forming a hydrophilic layer on the substrate.

The manufacturing method may further include performing a heating process or an ultraviolet irradiation process on any one of the substrates.

In the step of preparing the first substrate and the second substrate, a color filter may be formed on the first substrate, and a TFT array layer may be formed on the second substrate.

Alternatively, in the step of preparing the first substrate and the second substrate, a TFT array layer and a color filter may be formed on the second substrate.

The method of manufacturing a liquid crystal display may further include bending the first substrate and the second substrate such that a curved display surface is formed.

According to the liquid crystal display device and the manufacturing method thereof according to the embodiments of the present invention, a liquid crystal display device which forms a high-quality image with reduced texture and improved transmittance is provided.

Further, even when the liquid crystal display device is applied to a curved panel, reduction in transmittance due to substrate deformation is reduced.

1 is a cross-sectional view schematically showing a liquid crystal display device according to an embodiment of the present invention.
2 is a conceptual diagram showing how the degree of warpage of the upper and lower substrates varies in the bending process for forming the curved surface panel.
FIGS. 3A and 3B conceptually show that, in the case of the comparative example and the example, domain misalignment occurs due to the warping of the substrate.
4 is a cross-sectional view schematically showing a liquid crystal display device according to another embodiment.
5 is a plan view showing an exemplary shape of a pixel electrode employed in the liquid crystal display device of FIG.
6 is a cross-sectional view schematically showing a liquid crystal display according to another embodiment.
7 is a cross-sectional view schematically showing a liquid crystal display according to another embodiment.
8 is a cross-sectional view schematically showing a liquid crystal display according to another embodiment.
FIG. 9 is a perspective view showing the outline of a liquid crystal display device according to another embodiment.
10 is a block diagram illustrating a method of manufacturing a liquid crystal display device according to an embodiment.
Figs. 11A to 11C show that a liquid crystal mixture in which liquid crystal molecules and a vertical alignment additive are mixed, a vertical alignment additive in a liquid crystal mixture is self-aligned on a hydrophilic surface, and a pretilt is formed by electric field exposure.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention and methods of achieving them will be apparent with reference to the embodiments described in detail below with reference to the drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or corresponding components throughout the drawings, and a duplicate description thereof will be omitted .

In the following embodiments, the terms first, second, and the like are used for the purpose of distinguishing one element from another element, not the limitative meaning.

In the following examples, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

In the following embodiments, terms such as inclusive or possessive are intended to mean that a feature, or element, described in the specification is present, and does not preclude the possibility that one or more other features or elements may be added.

In the following embodiments, when a part of a film, an area, a component or the like is on or on another part, not only the case where the part is directly on the other part but also another film, area, And the like.

In the drawings, components may be exaggerated or reduced in size for convenience of explanation. For example, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and thus the present invention is not necessarily limited to those shown in the drawings.

1 is a cross-sectional view schematically illustrating a liquid crystal display 1000 according to an embodiment of the present invention.

The liquid crystal display 1000 includes a first substrate S1, a second substrate S2 disposed to face the first substrate S1, a first substrate S1 and a second substrate S2, And a liquid crystal layer 300 composed of a plurality of liquid crystal molecules 310.

In addition, a self-alignment layer (SAL) is formed between the first substrate (S1) and the liquid crystal layer (300). The self-aligned layer (SAL) is provided to form a predetermined pretilt angle on the liquid crystal molecules 310. That is, the long axis of the liquid crystal molecules 310 arranged in contact with the self-aligned layer SAL is not perpendicular to the surface of the first substrate S1, but the angle formed with the surface of the first substrate S1 is? . for example, greater than 85 degrees and less than 89.5 degrees.

The self-aligned layer (SAL) includes a vertical alignment additive 50 having a molecular structure in which a hydrophilic group 10 is formed at one end of the core molecule 20. A polymerized group 30 may be further formed at the other end of the core molecule 20. Although the hydrophilic group 10 and the polymerizable group 30 are shown at both ends of the core molecule 20 in the figure, the polymerizable group 30 is not limited thereto. May be omitted. The hydrophilic groups 10 are self-aligned toward the surface of the first substrate S1 and the major axis of the core molecules 20 is arranged at an angle of less than 90 degrees with respect to the surface of the first substrate S1, Aligning the tangent liquid crystal molecules 310 in the same direction.

The molecular structure of the vertically oriented additive 50 constituting the self-aligned layer (SAL) is a structure very similar to the liquid crystal molecule 310. For example, the core molecule 20 may be a biphenyl (mesogenic) biphenyl, or a plurality of benzene, or a cyclohexane ring.

The hydrophilic group 10 may include a hydroxyl group (? H), an amino group (? H2), or a ketone group (C = O). The hydrophilic group 10 may be composed of a polar group containing a polar structure component having an atom selected from N, O, S and P. [

The polymerizable group 30 may include, for example, acrylate, methacrylate, fluoroacrylate, oxetane, vinyloxy or epoxide groups.

An alignment layer (AL) may be formed between the second substrate (S2) and the liquid crystal layer (300). The alignment layer AL is made of a vertical alignment material and can vertically align the liquid crystal molecules of the liquid crystal layer 300 in contact with the alignment layer AL. The angle? 2 formed by the long axis of the liquid crystal molecules 310 of the liquid crystal layer 300 in contact with the alignment layer AL and the second substrate 500 may be about 90 degrees.

The alignment layer (AL) can be made of a general vertical alignment material, various kinds of organic alignment agents, and an inorganic alignment agent. Examples of the organic alignment agent include polyimide, lecitin, trichloro silane and trimethoxypropyl silane, hexadecyl trimethyl ammonium halides, alkylcarboxy Alkyl carboxylato monochromium salts, and the like. Examples of the inorganic alignment agent include SiO2, MgF2, and the like.

The liquid crystal layer 310 includes a plurality of liquid crystal molecules 310 and the liquid crystal molecules 310 are aligned in a direction perpendicular to the electric field direction when the electric field is formed in the liquid crystal layer 300, As shown in FIG. The liquid crystal molecules may be liquid crystal molecules having a negative dielectric constant anisotropy. When no electric field is formed in the liquid crystal layer 300, the liquid crystal molecules 310 are aligned in a direction substantially perpendicular to the surfaces of the first substrate S1 and the second substrate S2, and the self alignment layer SAL, Tilt angle defined by the alignment layer AL. In this embodiment, a self-alignment layer (SAL) and an alignment layer (AL) are formed so that a pretilt angle is formed only at a lower portion of the liquid crystal layer (300) and no pretilt is formed at an upper portion of the liquid crystal layer (300). The liquid crystal molecules in contact with the alignment layer SAL in the liquid crystal layer 300 have a pretilt angle of about 0.5 or more and the liquid crystal molecules 310 in contact with the alignment layer AL are not tilt- Plane. The long axis of the liquid crystal molecules 310 in contact with the alignment layer AL and the angle? 1 between the long axis of the liquid crystal molecules 310 in contact with the self alignment layer SAL and the first substrate S 1, Can be greater than 0.5 DEG and less than 15 DEG.

The shape of the pretilt angle distribution is determined in order to reduce the texture due to the misalignment caused by the bending process when the liquid crystal display device 1000 is applied to the curved panel.

2 is a conceptual diagram showing how the degree of warpage of the upper and lower substrates varies in the bending process for forming the curved surface panel.

Referring to the drawings, since the rim of the panel is fixed by the sealant 350, buckling occurs at the portion indicated by the point source, and the upper and lower plates are aligned with respect to the center of the panel. . As a result, a miss-aligned texture may occur and the transmittance may be reduced at this portion.

FIGS. 3A and 3B conceptually show that, in the case of the comparative example and the example, domain misalignment occurs due to the warping of the substrate.

3A differs from the present embodiment in the liquid crystal display device of the comparative example in which the same pre-tilt angle is applied on and under the liquid crystal layer, and FIG. 3B shows the liquid crystal display device of the embodiment in which the pre- It is about. Arrows indicate the major axis direction of the liquid crystal molecules.

In FIGS. 3A and 3B, upper and lower sides on the left are plan views before the bending, as shown in FIG. 2, as viewed from the direction of the liquid crystal molecules above and below the region where the twist occurs due to bending .

3A and 3B, upper and lower right sides are plan views after the bending process, as shown in Fig. 2, the plan view showing the directions of the liquid crystal molecules at the upper and lower portions of the region where the twist occurs at the time of bending . A rectangle indicated by a bold solid line indicates an area facing each other.

As shown in FIG. 3A, in the case of the comparative example, the pretilts in the regions facing each other are shifted from each other due to bending, thereby causing texture generation and reduction in transmittance. However, as shown in FIG. 3B, since the pretilt is applied only to the lower portion of the liquid crystal layer in the embodiment, even if misalignment due to twist occurs, the occurrence of a texture or a decrease in transmittance is expected to be insignificant.

In the case of the embodiment, the inventors varied the pretilt angles (? 1,? 2) in the liquid crystal layer, the lower and upper portions, and analyzed the influence of bending by computer simulation.

Pretilt angle (°) Transmittance (a.u.) Luminance variation θ1 θ2 delta alignment 30 mu m M / A One 0 One 0.17072 0.17072 0.00% One 0.2 0.8 0.17191 0.16988 -1.20% One 0.5 0.5 0.17339 0.16651 -4.00% One 0.8 0.2 0.17459 0.1625 -6.90% One One 0 0.17527 0.15955 -9.00%

In the above table, delta denotes a pretilt angle difference, and M / A denotes misalignment.

Referring to the above table, the larger the pretilt angle difference is, the less the luminance decrease due to misalignment appears. It is expected that the pre-tilt angle difference can be set to an appropriate value larger than 0.8 DEG, and the luminance variation amount can be adjusted to about 1%.

1, the upper part of the liquid crystal layer is shown without a pretilt and the lower part has a pretilt that is greater than 0.5 DEG, but this is an example, and it is assumed that the lower part of the liquid crystal layer is pre-tilted, Or the like.

Hereinafter, a detailed structure of a liquid crystal display according to various embodiments to which the above-described concept is applied will be described.

FIG. 4 is a cross-sectional view schematically illustrating a liquid crystal display 2000 according to another embodiment, and FIG. 5 is a plan view showing an exemplary shape of a pixel electrode PE employed in the liquid crystal display 2000 of FIG.

Referring to FIG. 4, a liquid crystal display 2000 includes a first substrate 100, a second substrate 500, and a liquid crystal layer 300. The liquid crystal molecules 310 on the lower side, that is, the liquid crystal molecules 310 adjacent to the first substrate 100, have a predetermined pretilt angle, about 0.5 DEG, The liquid crystal molecules 310 on the upper side, that is, the liquid crystal molecules 310 adjacent to the second substrate 500, are oriented substantially perpendicular to the second substrate 500 surface without pretilt. A self-aligned layer (SAL) having a structure as illustrated in FIG. 1 is formed on the first substrate 100 and an alignment layer AL made of a vertical alignment material is formed on the second substrate 500 Respectively.

 On the first substrate 100, a TFT array layer 120 and a pixel electrode PE are formed. The TFT array layer 120 includes a plurality of switching elements (TFT), and also includes a plurality of gate lines and a plurality of data lines (not shown).

The first substrate 100 may be a plastic substrate including not only a glass substrate but also a PET (polyethylene terephthalate), a PEN (polyethylenenaphthalate), a polyimide, or the like.

The switching element TFT is a thin film transistor including an active layer (AT), a gate electrode (GE), a source electrode (SE) and a drain electrode (DE).

A first insulating layer L1 as a gate insulating layer is formed on the gate electrode GE and an active layer AT is formed on the first insulating layer L1. A gate electrode GE and a source electrode SE are formed on the active layer AT so as to be spaced apart from each other and a second insulating layer L2 covering the gate electrode GE and the source electrode SE is formed.

 The active layer (AT) may be formed to include various materials. For example, the active layer (AT) may comprise an inorganic semiconductor material such as amorphous silicon or crystalline silicon. As another example, the active layer (AT) may include an oxide semiconductor. As another example, the active layer (AT) may include an organic semiconductor material.

The gate electrode GE, the source electrode SE and the drain electrode DE may be formed of a metal such as aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg) Selected from the group consisting of Ni, Ne, Ir, Cr, Ni, Ca, Mo, Ti, W and Cu. The at least one metal may be formed as a single layer or a plurality of layers.

The first insulating layer L1 and the second insulating layer L2 may be formed of various kinds of insulating materials. The first insulating layer L1 and the second insulating layer L2 may be formed of a single layer or a plurality of layers selected from SiO2, SiNx, SiON, Al2O3, TiO2, Ta2O5, HfO2, ZrO2, BST, have.

A planarization layer 150 may be further provided on the TFT array layer 120.

The pixel electrode PE is provided on the planarization layer 150 and is connected to the drain electrode DE of the switching element TFT through the planarization layer 150 and the second insulation layer L2.

A self-aligned layer (SAL) for forming pre-tilt of the liquid crystal molecules 310 is further formed on the pixel electrodes PE. A hydrophilic layer 170 may be further provided between the pixel electrode PE and the self-aligned layer SAL. The hydrophilic layer 170 is provided to provide a hydrophilic surface for the formation of a self-aligned layer (SAL). The hydrophilic layer 170 may be composed of a silicon nitride layer or a silicon oxide layer, or may be composed of a plurality of layers of a silicon nitride layer and a silicon oxide layer. The hydrophilic layer 170 is optional and can be omitted by hydrophilizing the surface of the pixel electrode PE and the planarization layer 150. [

A light shielding pattern BP, a color filter CF, an overcoat layer OC and a common electrode CE are formed on the second substrate 500 and an alignment film made of a vertical alignment material AL) may be formed. The second substrate 500 may be a glass substrate or a transparent plastic substrate, and the outer surface of the second substrate 500 may be a display surface DS.

The light blocking pattern BP is disposed on the second substrate 500 at a position corresponding to the area where the switching element TFT and the gate lines and data lines (not shown) are formed, and blocks the light. The arrangement position of the shielding pattern BP is exemplary and may be disposed on the first substrate 100. [

The color filter CF is disposed on the second substrate 500, and filters the color light. The arrangement of the color filters CF is exemplary and may be disposed on the first substrate 500.

The overcoat layer OC is disposed on the second substrate 500 on which the color filter CF is formed to planarize the upper surface of the second substrate 500. The overcoat layer OC may be omitted.

The common electrode CE is disposed on the second substrate 500 so as to face the pixel electrode PE and a reference voltage that defines the polarity of the voltage applied to the pixel electrode PE is applied. The common electrode CE may have a plate shape.

The pixel electrode PE may have a shape as shown in FIG.

5, the pixel electrode PE has a cruciform stem 200 and the cruciform stem 200 includes a horizontal stem 210 and a vertical stem 220. A plurality of fine branched electrodes 230 are formed to extend obliquely from the horizontal line base 210 and the vertical line base 220. The pixel region is partitioned into four domains by the cruciform stem portion 200.

The fine branch electrode 230 is shown in a straight line shape but can be deformed into a zigzag shape. Although the width S of the fine branch electrodes 230 and the width W of the fine slits 240 between the fine branch electrodes 230 are constantly shown, they can be modified differently and the liquid crystal control force, Can be properly designed.

The liquid crystal molecules 310 of the liquid crystal layer 300 are aligned in the initial alignment state in which no voltage is applied between the common electrode CE and the pixel electrode PE, And no pre-tilt is formed at a position adjacent to the alignment layer AL. When such a structure is applied to a curved panel, the generation of textures and the reduction of transmittance due to warping of the substrate are small.

6 is a cross-sectional view schematically showing a liquid crystal display 3000 according to another embodiment.

The liquid crystal display device 3000 of this embodiment differs from the embodiment of FIG. 4 in the arrangement positions of the self-alignment layer (SAL) and the alignment layer (AL). A self-aligned layer (SAL) for forming a predetermined pre-tilt angle is formed on the second substrate 500, and a self-aligned layer (SAL) for vertical orientation is formed on the first substrate 100. A hydrophilic layer 170 is formed between the common electrode CE and the alignment layer AL by way of example and by hydrophilizing the surface of the common electrode CE, the hydrophilic layer 170 is omitted . According to the above-described arrangement of the self-alignment layer (SAL) and the alignment layer (AL), the upper side of the liquid crystal layer 300 is oriented to have a predetermined pre-tilt angle and the lower side is oriented substantially vertically.

7 is a cross-sectional view schematically showing a liquid crystal display device 4000 according to still another embodiment.

The liquid crystal display device 4000 of this embodiment differs from the liquid crystal display device 2000 of Fig. 4 in the position of the color filter CF.

A color filter (CF) is formed on the first substrate (100). When such a structure is applied to a curved surface panel, it is considered that a large amount of deformation due to bending occurs in the substrate on the display surface (DS) side, that is, the second substrate 500. It is possible to reduce the occurrence of errors due to bending by disposing the color filter CF on the first substrate 100 having a relatively small deformation.

8 is a cross-sectional view schematically showing a liquid crystal display 5000 according to another embodiment.

The liquid crystal display 5000 of this embodiment differs from the embodiment of Fig. 7 in the arrangement position of the self-alignment layer (SAL) and the alignment layer (AL). A self-aligned layer (SAL) for forming a predetermined pre-tilt angle is formed on the second substrate 500, and a self-aligned layer (SAL) for vertical orientation is formed on the first substrate 100. A hydrophilic layer 170 is formed between the common electrode CE and the alignment layer AL by way of example and by hydrophilizing the surface of the common electrode CE, the hydrophilic layer 170 is omitted . According to the above-described arrangement of the self-alignment layer (SAL) and the alignment layer (AL), the upper side of the liquid crystal layer 300 is oriented to have a predetermined pre-tilt angle and the lower side is oriented substantially vertically.

FIG. 9 is a perspective view showing the outline of a liquid crystal display device 6000 according to another embodiment.

The liquid crystal display device 6000 of this embodiment has a structure bent to form the curved surface display surface DS. The above-described liquid crystal display devices 2000, 3000, 4000, and 5000 may all be applied to such a curved panel.

FIG. 10 is a block diagram illustrating a method of manufacturing a liquid crystal display device according to an embodiment. FIGS. 11A to 11C show the process of forming a self-alignment layer (SAL) from a liquid crystal mixture in which liquid crystal molecules and a vertical alignment additive are mixed.

Referring to FIG. 10, a first substrate and a second substrate each having a common electrode and a pixel electrode are prepared (S701), one of the first substrate and the second substrate is subjected to hydrophilic treatment, (S702). Further, a liquid crystal mixture in which the liquid crystal molecules and the vertical alignment additive are mixed is prepared (S703).

Detailed elements for driving the liquid crystal display device are further formed on the first substrate and the second substrate, which have been described in the above embodiments. For example, a color filter may be formed on a first substrate on which a common electrode is formed, and a TFT array layer may be formed on a second substrate on which pixel electrodes are formed, or on two substrates on which pixel electrodes are formed, Both the array layer and the color filter may be formed.

Either the first substrate or the second substrate is subjected to a hydrophilic treatment. The degree of hydrophilicity can be explained by the contact angle of the distilled water droplet to the treated surface. The smaller the contact angle, the more hydrophilic. The degree of hydrophilicity can be such that the contact angle is 70 DEG or less.

For the hydrophilic treatment, a hydrophilic layer may be formed on any of the above substrates. The hydrophilic layer may consist of a silicon nitride layer and / or a silicon oxide layer. The thickness of the hydrophilic layer may be approximately 1000 nm or less.

11A shows a liquid crystal mixture in which the liquid crystal molecules 310 and the vertical alignment additive 50 are mixed. The vertically oriented additive 50 has a molecular structure in which a hydrophilic group 10 is formed at one end of the core molecule 20. A polymerized group 30 may be further formed at the other end of the core molecule 20. Although the hydrophilic group 10 and the polymerizable group 30 are shown at both ends of the core molecule 20 in the figure, the polymerizable group 30 is not limited thereto. May be omitted. The vertically oriented additive 50 is homogeneously mixed well with the liquid crystal molecules 310 at room temperature without phase separation.

 The content of the vertical alignment additive 50 included in the liquid crystal mixture may be 0.001% to 0.5%. Here,% means weight%.

The liquid crystal mixture may further include an alkenyl single or alkoxy single. The content of alkenyl single or alkoxy single may range from approximately 1% to 70%.

For the hydrophilized substrate, a heating process may be further performed. The vertical orientation by the vertically oriented additive is sensitive to moisture, so that the vertical orientation force may be weakened when left at a high humidity. As a heating process, a heat treatment may be performed in a baking cell at about 120 ° C for 0.5 to 2 hours.

Further, the substrate subjected to hydrophilicity treatment may be further subjected to an ultraviolet ray irradiation process, and ultraviolet rays may be irradiated at an energy of about 50 mW or less.

The heating process or ultraviolet irradiation process may be omitted, either one of them may be performed, or both may be performed.

When the first substrate, the second substrate, and the liquid crystal mixture are prepared, the liquid crystal mixture is disposed between the first substrate and the second substrate and is cemented (S704).

Referring to FIG. 11B, the hydrophilic group 10 of the vertically oriented additive 50 is physically bonded and self-aligned to the hydrophilic surface HS by interaction with the hydrophilic surface HS. As shown, the self-aligned layer (SAL) is homotrophically oriented on the hydrophilic surface (HS).

Next, an electric field is applied to the liquid crystal mixture layer to irradiate light. In order to form an electric field, a voltage is applied between the common electrode and the pixel electrode formed on the first substrate and the second substrate, respectively. At this time, since the detailed pattern of the pixel electrode is designed to form the direction of the electric field corresponding to the pretilt angle, the liquid crystal molecules 310 align in a direction perpendicular to the direction of the electric field and form a pretilt angle.

When this state is maintained and ultraviolet light is irradiated on the liquid crystal mixture layer, the polymerizable group 30 of the vertically oriented additive 50 comes into contact with the liquid crystal molecules 310 and is fixed and cured as shown in FIG. 11C. This pre-tilt angle is maintained even after the electric field is not formed.

Further, the first substrate and the second substrate may be bended (S706) so that a curved display surface is formed.

According to the above-described steps, a liquid crystal display device having a curved surface with a small texture generation is manufactured. ;

While the present invention has been described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

1000, 2000, 3000, 4000, 5000, 6000: liquid crystal display
10: hydrophilic group 20: core molecule
30: polymerizable group 50: vertical alignment additive
100, S1: first substrate 120: TFT array layer
150: planarization layer 170: hydrophilic layer
200: cruciform stem 210: transverse stem
220: vertical stem 230: fine branch electrodes
240: fine slit 300: liquid crystal layer
310: liquid crystal molecule 500, S2: second substrate
SAL: self-alignment layer AL: alignment layer
GE: gate electrode SE: source electrode
DE: drain electrode PE: pixel electrode
CE: Common electrode CF: Color filter
DS: Display surface

Claims (21)

A first substrate;
A second substrate facing the first substrate;
A liquid crystal layer disposed between the first substrate and the second substrate, the liquid crystal layer comprising a plurality of liquid crystal molecules;
A liquid crystal layer formed between the first substrate and the liquid crystal layer,
Wherein the hydrophilic group is oriented toward the first substrate surface and the major axis of the core molecule is at least 90 DEG with respect to the first substrate surface, and a vertical alignment additive having a molecular structure in which a hydrophilic group is formed at one end of the core molecule, And a self-alignment layer arranged at a small angle. The method according to claim 1,
And a polymerized group is further formed on the other end of the core molecule. The method according to claim 1,
Wherein the core molecule comprises a mesogenic unit of biphenyl or a plurality of benzene or cyclohexane rings. The method according to claim 1,
And an alignment layer made of a vertical alignment material is further formed between the second substrate and the liquid crystal layer. 5. The method of claim 4,
Wherein a difference between an angle formed by the long axis of the liquid crystal molecules in contact with the alignment layer and the major axis of the liquid crystal molecules in contact with the alignment layer is greater than 0.5 DEG. 5. The method of claim 4,
Wherein an angle formed between the major axis of the liquid crystal molecules in contact with the self-aligned layer and the first substrate surface is greater than 85 DEG and less than 89.5 DEG. The method according to claim 1,
And the surface of the first substrate, which is in contact with the self-aligned layer, is hydrophilically processed. The method according to claim 1,
And a silicon nitride layer is further formed between the first substrate and the self-aligned layer. The method according to claim 1,
A color filter is formed on one of the first substrate and the second substrate, and a TFT array layer is formed on the other substrate. The method according to claim 1,
Wherein a color filter and a TFT array layer are formed on either one of the first substrate and the second substrate. The method according to claim 1,
Wherein the first substrate and the second substrate are bent so that a curved display surface is formed. Preparing a first substrate and a second substrate on which common electrodes and pixel electrodes are formed, respectively;
Mixing an additive comprising a plurality of molecules in which a hydrophilic group is formed at one end of a core molecule with a plurality of liquid crystal molecules to form a liquid crystal mixture;
Performing hydrophilic treatment on any one of the first substrate and the second substrate;
And arranging the liquid crystal mixture between the first substrate and the second substrate and performing electric field exposure. 13. The method of claim 12,
And a polymerizable group is further formed at the other end of the core molecule. 13. The method of claim 12,
Wherein the content of the additive contained in the liquid crystal mixture is 0.001% to 0.5%. 13. The method of claim 12,
Wherein the liquid crystal mixture further comprises alkenyl single or alkoxy single 13. The method of claim 12,
The step of hydrophilic treatment
Wherein a contact angle of the substrate with respect to distilled water is 70 DEG or less. 13. The method of claim 12,
The step of hydrophilic treatment
And forming a hydrophilic layer on one of the substrates. 13. The method of claim 12,
Further comprising performing a heating process or an ultraviolet irradiation process on any one of the substrates. 13. The method of claim 12,
In the step of preparing the first substrate and the second substrate,
Forming a color filter on the first substrate,
And forming a TFT array layer on the second substrate. 13. The method of claim 12,
In the step of preparing the first substrate and the second substrate,
And forming a TFT array layer and a color filter on the second substrate. 13. The method of claim 12,
And bending the first substrate and the second substrate such that a curved display surface is formed.

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