KR20160053264A - Compound for alignment layer, Alignment layer, Method of fabricating alignment layer and Liquid crystal display device including alignment layer - Google Patents

Abstract

The present invention relates to a resin composition comprising a repeating unit represented by the following formula: wherein R is selected from C1-C30 alkyl groups, m + n = 1 (n? M), m = 0.1 to 0.5, n = 0.5 to 0.9 And the like.

Description

TECHNICAL FIELD [0001] The present invention relates to a compound for alignment layer, an alignment layer, a method for producing an alignment layer, and a liquid crystal display device including the alignment layer.

TECHNICAL FIELD The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display device including an alignment film compound, an alignment film, a method of manufacturing an alignment film, and an alignment film capable of low temperature firing (or drying).

In recent years, as the society has become a full-fledged information age, the display field for processing and displaying a large amount of information has been rapidly developed, and as a flat panel display device having excellent performance of thinning, light weighting and low power consumption, Is replacing a conventional cathode ray tube (CRT).

Generally, the driving principle of a liquid crystal display device utilizes the optical anisotropy and polarization properties of a liquid crystal. Since the liquid crystal has a long structure, it has a directionality in the arrangement of molecules, and the direction of the molecular arrangement can be controlled by artificially applying an electric field to the liquid crystal.

Therefore, when the molecular alignment direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light is refracted in the molecular alignment direction of the liquid crystal by optical anisotropy, so that image information can be expressed.

In order to drive the liquid crystal as described above, an alignment film for arranging the initial liquid crystal is required. In general, the alignment film is a polymeric resin for aligning the liquid crystal in a predetermined direction, and is positioned in contact with the liquid crystal as the uppermost layer of the array substrate and the color filter substrate constituting the liquid crystal display device.

Hereinafter, the configuration of the liquid crystal display device will be described with reference to Fig.

1 is a diagram showing a cross-sectional configuration of a general liquid crystal display device.

1, the liquid crystal display includes first and second substrates 10 and 70 facing each other, and a liquid crystal layer 90 positioned between the first and second substrates 10 and 70 .

Gate interconnections (not shown) and data interconnections 30 are formed on the inside of the first substrate 10 to define pixel regions P intersecting each other with a gate insulating film 14 interposed therebetween. (Not shown) and the data line 30 constitute a thin film transistor Tr which is a switching element.

The thin film transistor Tr includes a gate electrode 12, a semiconductor layer 20, a source electrode 32, and a drain electrode 34. The gate electrode 12 is connected to the gate wiring, and the source electrode 32 is connected to the data line 30. The semiconductor layer 20 is composed of an active layer 20a made of pure amorphous silicon and an ohmic contact layer 20b made of impurity amorphous silicon.

A protective layer 40 is formed which has the data line 30 and the drain contact hole 42 covering the thin film transistor Tr and exposing the drain electrode 34. On the protective layer 40, (50) and the common electrode (52) are formed.

The pixel electrode 50 is connected to the drain electrode 34 through the drain contact hole 42. The pixel electrode 50 and the common electrode 52 are alternately arranged and form a horizontal electric field with respect to the surface of the first substrate 10.

A first alignment layer 60 is formed on the pixel electrode 50 and the common electrode 52.

A black matrix 72 is formed inside the second substrate 70 in correspondence with the gate wiring (not shown), the data line 30 and the thin film transistor Tr, The color filter layer 74 is formed.

A second alignment layer 80 is formed on the color filter layer 74.

A liquid crystal layer 90 is positioned between the first and second alignment layers 60 and 80 and the initial alignment of the liquid crystal molecules in the liquid crystal layer 90 is controlled by the first and second alignment layers 60 and 80 .

The first and second polarizers 92 and 94 are positioned outside the first substrate 10 and the second substrate 70, respectively. The first and second polarizing plates 92 and 94 have light transmission axes perpendicular to each other.

As described above, the first alignment layer 60 and the second alignment layer 80 function to align liquid crystal molecules in the liquid crystal layer 90 in a predetermined direction. For this, the first alignment layer 60 and the second alignment layer 80 The alignment process for the alignment film 80 proceeds.

Each of the first and second alignment layers 60 and 80 may be formed of a polyimide represented by the following general formula (1). In the general formula (1), R1 may be selected from the following general formula (2)

[Chemical Formula 1]

(2)

(3)

The steps of forming the first and second alignment films 60 and 80 made of polyimide are shown in Fig.

As shown in FIG. 2, the substrate on which the pixel electrode, the common electrode, and the like are formed is cleaned (ST1), and the polyimide solution of Formula 1 described above is coated. (ST2)

Subsequently, the substrate is dried (first sintering) for about 100 seconds under a temperature of about 100 deg. C (ST3), and the sintering (secondary sintering) process is performed for about 1000 seconds under a temperature of about 230 deg. (ST4)

Thereafter, a rubbing process using a rubbing cloth is performed to form an alignment film. (ST5)

As described above, the step of forming a conventional alignment film using polyimide requires a firing step (ST4) at a temperature of about 230 deg. C for imidization reaction of polyimide.

In recent years, flexible substrates such as plastics are used for the first substrate (10 in Fig. 1) and / or the second substrate (70 in Fig. 1) of the liquid crystal display device for the flexible display device.

However, in the case of the flexible substrate, deformation occurs at the temperature of the above-mentioned baking process of the orientation film.

Therefore, when a conventional alignment film is used for a flexible display device using a flexible substrate, the production yield is lowered and the display quality deteriorates due to substrate deformation.

The present invention aims to solve the problem of substrate deformation due to a high firing temperature of the conventional alignment film.

In order to solve the above-mentioned problems, the present invention provides a polymerizable composition containing a repeating unit represented by the following formula: wherein R is selected from C1-C30 alkyl groups, m + n = 1 (n? M) 0.5, and n = 0.5 to 0.9.

In another aspect, the present invention includes a material having a repeating unit represented by the following formula: wherein R is selected from C1 to C30 alkyl groups, m + n = 1 (n? M) 0.5 and n = 0.5 to 0.9.

According to another aspect of the present invention, there is provided a method for manufacturing a liquid crystal display device, comprising the steps of: forming a layer of an alignment material by coating an alignment material solution containing a compound for an alignment layer represented by the following formula and a solvent on a substrate; Rubbing the layer of the alignment material, and irradiating the rubbed alignment material layer with UV light to photo-crosslink the compound for the alignment layer, wherein R is selected from C1 to C30 alkyl groups and m + n = 1 (n? m), m = 0.1 to 0.5, and n = 0.5 to 0.9.

In the method of manufacturing an alignment film of the present invention, the UV irradiation step is performed under a dose of 2 to 10 J / cm 2.

In the method of manufacturing an alignment film of the present invention, the drying step is performed at a temperature of 20 to 150 ° C.

In the method for producing an alignment film of the present invention, the solvent has a volatilization temperature lower than the temperature of the drying step and is volatilized in the drying step.

In the method of producing an alignment film of the present invention, the solvent is further volatilized in the step of photo-crosslinking the compound for alignment film by absorbing the UV.

In the method of producing an alignment film according to the present invention, the solvent includes at least one of hexyl acetate, butyl cellosolve, methylethylketone, methanol, and toluene.

In another aspect, the present invention provides a liquid crystal display device comprising a first substrate, pixel electrodes positioned on the first substrate, a first alignment film covering the pixel electrodes, a second substrate facing the first substrate, And a liquid crystal layer interposed between the first and second alignment films, wherein the first and second alignment films are disposed between the first and second alignment films, Wherein at least one of the alignment layers comprises a material having a repeating unit represented by the following formula: R is selected from a C1 to C30 alkyl group, m + n = 1 (n? M), m = 0.1 to 0.5, and n = 0.5 to 0.9.

The liquid crystal display device of the present invention may further include a first polarizer disposed on the outer surface of the first substrate and a second polarizer disposed between the second substrate and the second alignment film.

The liquid crystal display device of the present invention is characterized by further comprising a pattern drifter positioned between the second substrate and the second polarizing plate.

In the liquid crystal display device of the present invention, the first and second substrates are flexible substrates.

In the present invention, by forming the alignment film with polyacrylate capable of low-temperature firing, substrate deformation by the alignment film formation step can be minimized. Therefore, the flexible display device can be provided without a problem of deformation of the substrate.

Further, by providing the in-pole type liquid crystal display device in which the upper polarizer plate is formed in the display panel, the viewing angle of the liquid crystal display device can be improved.

In addition, in the incell-pole type liquid crystal display device, since the alignment film capable of low-temperature firing is formed on the upper polarizer plate, the upper polarizer plate can be prevented from being damaged by the alignment film formation process.

1 is a cross-sectional view of a general liquid crystal display device.
Fig. 2 is a flowchart for explaining a conventional process for forming an alignment film.
3 is a schematic plan view of a liquid crystal display according to a first embodiment of the present invention.
4 is a cross-sectional view taken along line IV-IV in Fig.
5 is a flow chart for explaining the alignment film forming process of the present invention.
6 is a schematic cross-sectional view of a liquid crystal display device according to a second embodiment of the present invention.
7A and 7B are views showing viewing angles in a 3D liquid crystal display device.

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

FIG. 3 is a schematic plan view of a liquid crystal display according to a first embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG.

3 and 4, the liquid crystal display according to the first embodiment of the present invention includes a first substrate 101 and a second substrate 150 facing each other, First and second alignment layers 140 and 160 positioned inside the first and second alignment layers 140 and 160 and a liquid crystal layer 170 disposed between the first and second alignment layers 140 and 160.

Each of the first and second substrates 101 and 150 may be a glass substrate or a flexible plastic substrate.

A gate wiring 103 is formed in the first substrate 101 along the first direction and a data wiring 112 intersecting the gate wiring 103 through the gate insulating film 110 is formed in the second Direction. The pixel region P is defined by intersection of the gate wiring 103 and the data wiring 112.

In the pixel region P, the gate line 103 and the thin film transistor Tr electrically connected to the data line 112 are located.

The thin film transistor Tr includes a gate electrode 105 formed on the first substrate 101 and a semiconductor layer (not shown) which overlaps the gate electrode 105 with the gate insulating film 110 interposed therebetween. And a source electrode 114 and a drain electrode 116 spaced from each other on the semiconductor layer (not shown).

The gate electrode 105 is connected to the gate wiring 103 and the source electrode 114 is connected to the data wiring 112. The source electrode 114 is spaced apart from the drain electrode 116. The semiconductor layer (not shown) may include an active layer (not shown) made of pure amorphous silicon and an ohmic contact layer (not shown) made of impurity amorphous silicon. Meanwhile, the semiconductor layer (not shown) may have a single layer structure of an oxide semiconductor material.

The drain electrode 116 extends to overlap the common wiring 107 to form a storage capacitor StgC. That is, the overlapped portion of the common wiring 107 becomes the first storage electrode, the overlapped portion of the drain electrode 116 becomes the second storage electrode, and the gate insulating film between the first and second storage electrodes (110) becomes a dielectric layer.

On the first substrate 101 are formed a common wiring 107 which is parallel to the gate wiring 103 and auxiliary common electrodes 109a and 109b extending from the common wiring 107 in parallel with the data wiring 112, , And 109b may be formed.

A first protective layer 118 made of an inorganic insulating material such as silicon oxide or silicon nitride is formed so as to cover the data line 112 and the thin film transistor Tr and a red R, green (G), and blue (B) color filter layers 122 are formed. Meanwhile, the color filter layer 122 may be formed on the second substrate as in the second embodiment.

In the case where the color filter layer is formed on the second substrate as the upper substrate, the black matrix is formed to have a larger width than the data lines in consideration of the alignment margin, thereby causing a problem that the aperture ratio is reduced.

However, in the case where the color filter layer 122 is formed on the first substrate 101 on which the thin film transistor Tr is formed, since the width of the black matrix can be reduced, the aperture ratio is improved.

On the color filter layer 122, a second passivation layer 124 made of an organic insulating material such as photo-acryl and having a flat surface is formed. A drain contact hole 119 is formed in the second passivation layer 124 and the color filter layer 122 and the first passivation layer 118 to expose the drain electrode 116, A common contact hole 120 for exposing at least one of the auxiliary common electrodes 109a and 109b is formed in the color filter layer 122 and the first passivation layer 118 and the gate insulating layer 110, Is formed.

Either one of the first and second protective layers 118 and 124 may be omitted.

The pixel electrode 130 and the common electrode 132 are alternately arranged on the second passivation layer 124.

The pixel electrode 130 is connected to the drain electrode 116 through the drain contact hole 119 and the common electrode 132 is electrically connected to the auxiliary common electrodes 109a and 109b. 3 shows that the end of the common electrode 132 is connected to the auxiliary common wiring 134 and the auxiliary common wiring 134 is connected to the auxiliary common electrode 109a through the common contact hole 120. [ However, as far as the common electrode 132 is electrically connected to the common wiring 107, there is no limitation in the connection relation.

One of the pixel electrode 130 and the common electrode 132 is formed on the first passivation layer 118 and has a plate shape and the other has a plate shape having an opening, Field switching scheme. In addition, the pixel electrode 130 may have a plate shape, and the common electrode 132 may be formed on the second substrate 150 to form a vertical electric field.

In addition, a shield pattern 136 extending from the auxiliary common wiring 134 and corresponding to the data wiring 112 and the auxiliary common electrodes 109a and 109b is formed.

When the shield pattern 136 is made of an opaque metal material, the light leakage around the data line 112 is cut off. Therefore, the width of the black matrix 152 formed on the second substrate 150 can be minimized, (152) can be omitted.

A first alignment layer 140 is formed on the pixel electrode 130 and the common electrode 132.

A black matrix 152 for covering the thin film transistor Tr and the gate wiring 103 and the data wiring 112 is formed inside the second substrate 150 and the black matrix 152 is formed And an overcoat layer 154 is formed. A second alignment layer 160 is formed on the overcoat layer 154. At this time, the overcoat layer 154 is a planarization layer and may be omitted.

A liquid crystal layer 170 is formed between the first and second alignment layers 140 and 160 and the initial alignment of the liquid crystal molecules in the liquid crystal layer 170 is performed by the first and second alignment layers 140 and 160 .

First and second polarizers 182 and 184 are positioned outside the first substrate 101 and the second substrate 150, respectively. The first and second polarizing plates 182 and 184 have light transmission axes perpendicular to each other.

Although not shown, a backlight unit may be disposed under the first polarizer plate 182. On the other hand, when the liquid crystal display device is of a reflective type, the backlight unit may be omitted.

In addition, when the liquid crystal display device is used for 3D display, the patterned retarder may be located outside the second polarizer plate 184. [

As described above, the first and second alignment layers 140 and 160 for initial alignment of liquid crystal molecules in the liquid crystal layer 170 are formed in the liquid crystal display device. The first and second alignment layers 140 and 160, At least one of them is composed of a polyacrylate (PA) compound having a repeating unit represented by the following formula (4).

[Chemical Formula 4]

In Formula 4, R is selected from alkyl groups. For example, R may be selected from C1 ~ C30 alkyl group, CH _3, may be a C ₂ H ₅ or C ₄ H _9. In addition, m + n = 1 (n? M), m = 0.1 to 0.5, n = 0.5 to 0.9, and preferably m = 0.16 and n = 0.84. The molecular weight may be from 50,000 to 200,000.

Since the first and second alignment layers 140 and 160 made of the polyacrylate compound are formed by the low temperature firing process at a temperature of about 20 to 150 degrees Celsius, the first and second alignment layers 140 and 160 It is possible to prevent the liquid crystal display device from being damaged by the forming process temperature.

For example, when the first and second substrates 101 and 150 are flexible substrates such as plastic, there is a problem that the flexible substrate is damaged at 230 deg. C, which is a process temperature for forming a conventional alignment film.

However, since the first and second alignment films 140 and 160 in the present invention are capable of low-temperature firing, the above-described problems can be avoided.

In the above description, the first and second substrates 101 and 150 are flexible substrates, but it is needless to say that a generally used glass substrate may be used.

The process for forming the second alignment layer 160 on the second substrate 150 will be described with reference to FIG. 5, which is a flowchart for explaining the alignment layer forming process of the present invention.

First, the cleaning process is performed on the second substrate 150 on which the overcoat layer 154 is formed. (ST100)

Next, an alignment material solution (PA) containing a compound represented by the following general formula (5) and a solvent is coated on the overcoat layer 154 to form an alignment material layer. (ST110)

[Chemical Formula 5]

In Formula 5, R is selected from an alkyl group. For example, R may be selected from C1 ~ C30 alkyl group, CH _3, may be a C ₂ H ₅ or C ₄ H _9. In addition, m + n = 1 (n? M), m = 0.1 to 0.5, n = 0.5 to 0.9, and preferably m = 0.16 and n = 0.84.

Further, the solvent is characterized in that it has a boiling point or a volatilization temperature lower than the temperature of the subsequent drying (calcining) process, or a material capable of absorbing light in the UV spectrum of a subsequent UV irradiation process. That is, the solvent is volatilized in the drying process and then further volatilized in the UV irradiation process.

For example, at least one of cellosolve solvent, Acetate solvent, ketone solvent, alcohol solvent, and aromatic solvent may be used as the solvent. More specifically, the solvent may be selected from hexyl acetate, butyl cellosolve, methylethylketone (MEK), methanol, and toluene.

The compound represented by the above formula (5) may be used in an amount of about 1 to 5% by weight based on the total weight of the alignment solution, with the remainder being the solvent.

The copolymer (co-polymer) represented by the above formula (5) can be obtained by the following synthesis example.

Synthetic example

1. First synthetic example

, Methyl methacrylate (MMA) (5.1 g, 0.051 mol), 2,2-dinitrile / -azoisomalganoic acid (AIBN) (0.065 g), and 2-methoxy-4-formyl phenyl methacrylate (MFPMA) dioxane (6 ml) was placed in a vial and purged with nitrogen for 10 to 12 minutes to remove oxygen. The mixture was then polymerized for 2.5 hours at 700 degrees Celsius. The reactor was cooled and the resulting material was dissolved in 20 ml of dioxane and then precipitated in a 7 to 8-fold excess of isopropyl alcohol. The precipitation process was repeatedly purified and then dried to obtain a copolymer. (yield: 65 to 67%, intrinsic viscosity (chloroform): 0.30 dl / g)

The copolymer contained 14.9 mol% of MFPMA and 85.1 mol% of MMA.

2. Synthesis Example 2

(1.98g, 0.009mol), ethyl methacrylate (EMA) (5.81g, 0.051mol), 2,2-dinitrile / azoisomassylanoic acid (AIBN) (0.065g) and dioxane And purged with nitrogen for 10 to 12 minutes to remove oxygen. The mixture was then polymerized for 2.5 hours at 700 degrees Celsius. The reactor was cooled and the resulting material was dissolved in 20 ml of dioxane and then precipitated in a 7 to 8-fold excess of isopropyl alcohol. The precipitation process was repeatedly purified and then dried to obtain a copolymer. (yield: 65 to 67%, intrinsic viscosity (chloroform): 0.35 dl / g)

The copolymer contained 14.7 mol% of MFPMA and 85.3 mol% of EMA.

3. Third synthetic example

Molecular weight analysis was performed on vials of MFPMA (1.98 g, 0.009 mol), butyl methacrylate (BMA) (7.24 g, 0.051 mol), 2,2-dinitrile / azoisomassylanoic acid (AIBN) And purged with nitrogen for 10 to 12 minutes to remove oxygen. The mixture was then polymerized for 2.5 hours at 700 degrees Celsius. The reactor was cooled and the resulting material was dissolved in 20 ml of dioxane and then precipitated in a 7 to 8-fold excess of isopropyl alcohol. The precipitation process was repeatedly purified and then dried to obtain a copolymer. (yield: 67 to 69%, intrinsic viscosity (chloroform): 0.33 dl / g)

The copolymer contained 14.7 mol% MFPMA and 85.3 mol% BMA.

Next, a drying process is performed on the layer of the oriented alignment material. (ST120) The drying process may be performed at a temperature of about 20 to 150 DEG C for about 60 to 600 seconds, and the solvent in the alignment solution is completely or partially removed by the drying process.

Next, the rubbing process is performed on the alignment material layer. (ST130) The alignment process may be performed using a rubbing cloth, whereby the initial alignment of the liquid crystal molecules in the liquid crystal layer 170 is determined.

Next, photo-crosslinking of the substance represented by the above-mentioned chemical formula 5 is carried out by irradiating UV with respect to the orientation material layer. Accordingly, the second alignment layer 160 including the polyacrylate compound of Formula 4 can be prepared.

At this time, UV is irradiated under a dose of about 2 to 10 J / cm 2, and may be non-polarized and non-collimated UV-B (254 nm).

Conventional alignment films using polyimide require a firing step at a relatively high temperature of 230 degrees Celsius for imidization reaction, and the flexible substrate is damaged by such a high firing step.

However, as described above, since the alignment film of the present invention is made of a polyacrylate compound capable of being fired (or dried) at a relatively low temperature (20 to 150 degrees Celsius) and photo-crosslinking proceeds by UV irradiation, It is possible to prevent the components such as the substrate from being damaged.

6 is a schematic cross-sectional view of a liquid crystal display device according to a second embodiment of the present invention.

6, a liquid crystal display device according to a second embodiment of the present invention includes a first substrate 201 and a second substrate 250 facing each other, a first substrate 201 and a second substrate 201, The first and second alignment films 240 and 260 positioned on the inner side of the first substrate 201 and the second substrate 250 and the first polarizer 282 positioned on the outer side of the first substrate 201, A second polarizing plate 284 positioned between the second alignment layers 260 and a liquid crystal layer 270 disposed between the first and second alignment layers 240 and 260.

Each of the first and second substrates 201 and 250 may be a flexible plastic substrate, and the light transmission axes of the first and second polarizers 282 and 284 are perpendicular to each other. Each of the first and second substrates 201 and 250 may be a glass substrate.

The patterned retarder may be included between the second polarizer 284 and the second substrate 250. When the patterned retarder is included, the liquid crystal display device is used for 3D image display.

The structure in which the second polarizing plate 284 is positioned between the first and second substrates 201 and 250 is referred to as an in-cell pol structure. When the pattern reliader is formed between the second substrate 250 and the second polarizing plate 284 in the in-cell polarized structure liquid crystal display device, since the distance between the display pixel and the pixel row of the pattern reliader decreases, The upper and lower viewing angles are improved.

7A and 7B showing the viewing angle in the 3D display device, when the upper polarizer pol and the patterned retarder PR are located on the outer surface of the second substrate SUB2, The viewing angle decreases because the distance between the display pixel PR and the display pixel increases. (Fig. 7A)

7B, the upper polarizer pol and the pattern reliader PR are positioned between the first substrate SUB1 and the second substrate SUB2, or more precisely, on the inner surface of the second substrate SUB2, The viewing angle increases because the distance between the pattern reliader PR and the display pixel decreases.

In the present invention, the viewing angle in the 3D liquid crystal display device can be improved by forming the second polarizing plate 284 and the patterned retarder 286, which are the upper polarizing plate, inside the second substrate 250.

Referring again to FIG. 6, a gate wiring (103 in FIG. 3) is formed along the first direction on the inner side of the first substrate 201, and the gate wiring 103 are formed along the second direction. The pixel region P is defined by intersection of the gate wiring (103 in FIG. 3) and the data wiring 212. Further, common wirings (107 in Fig. 3) spaced apart in parallel to the gate wirings and auxiliary common electrodes 209a and 209b extending therefrom in parallel with the data wirings are formed.

In the pixel region P, a thin film transistor (Tr in FIG. 3) electrically connected to the gate wiring (103 in FIG. 3) and the data wiring 212 is located.

The thin film transistor Tr includes a gate electrode (105 in Fig. 3) formed on the first substrate 201 and a gate electrode (105 in Fig. 3) overlapping the gate electrode A semiconductor layer (not shown), and a source electrode (114 in FIG. 3) and a drain electrode (116 in FIG. 3) spaced from each other on the semiconductor layer (not shown).

The gate electrode (105 in FIG. 3) is connected to the gate wiring (103 in FIG. 3), and the source electrode (114 in FIG. 3) is connected to the data wiring 212. The source electrode (114 in FIG. 3) is spaced apart from the drain electrode (116 in FIG. 3). The semiconductor layer (not shown) may include an active layer (not shown) made of pure amorphous silicon and an ohmic contact layer (not shown) made of impurity amorphous silicon. Meanwhile, the semiconductor layer (not shown) may have a single layer structure of an oxide semiconductor material.

A first protective layer 218 made of an inorganic insulating material such as silicon oxide or silicon nitride is formed covering the data line 212 and the thin film transistor (Tr in FIG. 3) A second protective layer 224 made of an organic insulating material such as photo-acryl and having a flat surface is formed.

A drain contact hole (119 in FIG. 3) is formed in the second passivation layer 224 and the first passivation layer 218 to expose the drain electrode (116 in FIG. 3). Either one of the first and second protective layers 218 and 224 may be omitted.

The pixel electrode 230 and the common electrode 232 are alternately arranged on the second passivation layer 224.

The pixel electrode 230 is connected to the drain electrode (116 in FIG. 3) through the drain contact hole (119 in FIG. 3). In addition, the common electrode 232 may be electrically connected to a common wiring (107 in FIG. 3).

A first alignment layer 240 is formed on the pixel electrode 230 and the common electrode 232.

A thin film transistor Tr and a black matrix 252 covering the gate wiring (103 in FIG. 3) and the data wiring 212 are formed in the second substrate 250, P, the color filter layer 256 is formed.

A pattern drift layer 286 and a second polarizing plate 284 are formed on the color filter layer 256 and a second alignment layer 260 is formed on the second polarizing plate 284. That is, the liquid crystal display device according to the second embodiment of the present invention has an in-pole type structure.

A liquid crystal layer 270 is formed between the first and second alignment layers 240 and 260. The initial alignment of the liquid crystal molecules in the liquid crystal layer 270 is performed by the first and second alignment layers 240 and 260 .

The first and second alignment layers 240 and 260 of the present invention are formed of a polyacrylate (PA) compound having the repeating unit represented by Chemical Formula 4 and can be formed by a low-temperature firing process.

Therefore, it is possible to prevent the flexible substrate from being damaged by the polyimide alignment film which is required in the conventional high-temperature process.

In addition, the liquid crystal display device according to the second embodiment of the present invention has an in-cell structure and has an effect of improving the viewing angle in 3D image display. In this structure, the second alignment film 260 is formed on the patterned retarder 286 and the second polarizer 284 in a state where the patterned retarder 286 and the second polarizer 284 are formed.

In the case of using a polyimide alignment film which requires a high-temperature firing process in the related art, there may be a problem of lowering the contrast ratio due to the polarizing plate damage or a cross-talk problem of the 3D image due to the patterned retarder damage. However, in the present invention, since the polyacrylate alignment film capable of being fired at a temperature of 150 DEG C or less is used, the above-described problem is prevented.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It can be understood that it is possible.

101, 201: a first substrate 150, 250: a second substrate
103: gate wiring 105: gate electrode
107: common wiring 109a, 109b, 209a, 209b: auxiliary common electrode
110, 210: gate insulating film 112, 212: data wiring
114: source electrode 116: drain electrode
118, 218: first protective layer 124, 224: second protective layer
130, 230: pixel electrode 132, 232: common electrode
140, 240: first alignment layer 160, 260: second alignment layer
170, 270: liquid crystal layers 182, 282: first polarizing plate
184, 284: second polarizer plate 286: pattern-retarder

Claims (12)

Wherein R has a repeating unit represented by the following formula: R is selected from C1-C30 alkyl groups, m + n = 1 (n? M), m = 0.1 to 0.5 and n = 0.5 to 0.9 Compound for alignment film.

Wherein R is selected from C1-C30 alkyl groups, m + n = 1 (n? M), m = 0.1 to 0.5, n = 0.5 to 0.9 .

Forming an alignment material layer on the substrate by coating an aligning material solution containing a compound for alignment layer represented by the following formula and a solvent;
Drying the layer of oriented material;
Rubbing the layer of oriented material;
Irradiating the rubbed alignment material layer with UV light to photo-crosslink the compound for alignment layer
Lt; / RTI >
R is selected from C1-C30 alkyl groups, m + n = 1 (n? M), m = 0.1 to 0.5, and n = 0.5 to 0.9.

The method of claim 3,
Wherein the UV irradiation step is performed under a dose of 2 to 10 J / cm 2.
The method of claim 3,
Wherein the drying step is performed at a temperature of 20 to 150 ° C.
The method of claim 3,
Wherein the solvent has a volatilization temperature lower than the temperature of the drying step and is volatilized in the drying step.
The method according to claim 6,
Wherein the solvent is further volatilized in the step of photo-crosslinking the compound for alignment film by absorbing the UV.
8. The method according to claim 6 or 7,
Wherein the solvent comprises at least one of hexyl acetate, butyl cellosolve, methylethylketone, methanol, and toluene.
A first substrate;
A pixel electrode disposed on the first substrate;
A first alignment layer covering the pixel electrode;
A second substrate facing the first substrate;
A common electrode disposed on one of the first and second substrates;
A second alignment layer located inside the second substrate;
And a liquid crystal layer disposed between the first and second alignment films,
Wherein at least one of the first and second alignment layers comprises a material having a repeating unit represented by the following formula, R is selected from a C1 to C30 alkyl group, m + n = 1 (n? M) m is from 0.1 to 0.5, and n is from 0.5 to 0.9.

10. The method of claim 9,
A first polarizer disposed on the outer surface of the first substrate;
And a second polarizing plate disposed between the second substrate and the second alignment film.
11. The method of claim 10,
And a patterned retarder positioned between the second substrate and the second polarizer.
10. The method of claim 9,
Wherein the first and second substrates are flexible substrates.

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