KR102145981B1 - 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 has a repeating unit represented by the following formula, R is selected from C1 ~ C30 alkyl group, m + n = 1 (n≥m), m = 0.1 ~ 0.5, n = 0.5 ~ 0.9 It provides a compound for an alignment layer, characterized in that.

Description

Compound for alignment layer, alignment layer, alignment layer manufacturing method, and liquid crystal display device including alignment layer {Compound for alignment layer, Alignment layer, Method of fabricating alignment layer and Liquid crystal display device including alignment layer}

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

In recent years, as society enters the era of full-fledged information, the field of display processing and displaying a large amount of information has rapidly developed, and it is a liquid crystal display device as a flat panel display device with excellent performance of thinner, lighter, and low power consumption Is replacing the existing cathode ray tube (CRT).

In general, the driving principle of a liquid crystal display uses the optical anisotropy and polarization properties of the liquid crystal. Since the liquid crystal has a thin and long structure, it has 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, if the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal changes, and light is refracted in the molecular arrangement direction of the liquid crystal due to optical anisotropy, so that image information can be expressed.

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

Hereinafter, a configuration of a liquid crystal display device will be described with reference to FIG. 1.

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

As shown in FIG. 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. Include.

Inside the first substrate 10, a gate wiring (not shown) and a data wiring 30 are formed to cross each other through a gate insulating layer 14 to define a pixel region P, and the gate wiring ( (Not shown) and a thin film transistor Tr as a switching element are formed at the intersection of the data line 30.

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 line, and the source electrode 32 is connected to the data line 30. The semiconductor layer 20 includes an active layer 20a made of pure amorphous silicon and an ohmic contact layer 20b made of impurity amorphous silicon.

A protective layer 40 having a drain contact hole 42 covering the data line 30 and the thin film transistor Tr and exposing the drain electrode 34 is formed, and a pixel electrode is formed on the protective layer 40. 50 and a common electrode 52 are formed.

The pixel electrode 50 is connected to the drain electrode 34 through the drain contact hole 42. The pixel electrodes 50 and the common electrodes 52 are alternately arranged with each other 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.

Inside the second substrate 70, a black matrix 72 is formed corresponding to the gate line (not shown), the data line 30, and the thin film transistor Tr, and the pixel region P The color filter layer 74 is formed corresponding to.

In addition, 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 arrangement of liquid crystal molecules in the liquid crystal layer 90 is achieved by the first and second alignment layers 60 and 80. Is determined.

In addition, first and second polarizing plates 92 and 94 are positioned outside each of the first and second substrates 10 and 70. 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 arrange liquid crystal molecules in the liquid crystal layer 90 in a predetermined direction. To this end, the first alignment layer 60 and the second alignment layer 80 An alignment process for the alignment layer 80 is performed.

Each of the first and second alignment layers 60 and 80 is made of a polyimide represented by Formula 1 below. In Formula 1, R1 may be selected from Formula 2 below, and R2 may be Formula 3 below.

[Formula 1]

[Formula 2]

[Chemical Formula 3]

The process of forming the first and second alignment layers 60 and 80 made of such polyimide is shown in FIG. 2.

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

Next, drying (primary firing) for about 100 seconds under conditions of about 100 degrees Celsius (ST3), and firing (second firing) for about 1000 seconds under conditions of about 230 degrees Celsius is performed. (ST4)

Thereafter, an alignment layer is formed by performing a rubbing process using a rubbing cloth. (ST5)

As described above, the conventional process of forming an alignment layer using polyimide requires a firing process (ST4) under conditions of about 230 degrees Celsius for the imidation reaction of the polyimide.

Meanwhile, recently, for a flexible display device, a flexible substrate such as plastic is used as a first substrate (10 in FIG. 1) and/or a second substrate (70 in FIG. 1) of a liquid crystal display device.

However, in the case of the flexible substrate, deformation occurs at the firing process temperature of the alignment layer described above.

Therefore, when a conventional alignment layer is used in a flexible display device using a flexible substrate, a manufacturing yield decreases and a problem of display quality decrease due to substrate deformation occurs.

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

In order to solve the above problems, the present invention has a repeating unit represented by the following formula, R is selected from an alkyl group of C1 to C30, m+n=1 (n≥m), and m=0.1~ It provides a compound for an alignment layer, characterized in that 0.5, n = 0.5 ~ 0.9.

In another aspect, the present invention includes a material having a repeating unit represented by the following formula, R is selected from an alkyl group of C1 ~ C30, m+n=1 (n≥m), and m=0.1~ It provides an alignment layer, characterized in that 0.5, n = 0.5 ~ 0.9.

In another aspect, the present invention provides a step of forming an alignment material layer by coating an alignment material solution including a compound for an alignment layer represented by the following formula and a solvent on a substrate, drying the alignment material layer, and Rubbing the alignment material layer, and irradiating UV to the rubbed alignment material layer to photocrosslink the alignment layer compound, wherein R is selected from an alkyl group of C1 to C30, and m+n=1 (n≥m), and m=0.1 to 0.5, and n=0.5 to 0.9.

In the method of manufacturing an alignment layer of the present invention, the UV irradiation step is characterized in that it proceeds under a dose condition of 2 to 10 J/cm 2.

In the method of manufacturing the alignment layer of the present invention, the drying step is characterized in that it proceeds under a temperature condition of 20 to 150 degrees Celsius.

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

In the method of manufacturing an alignment layer of the present invention, the solvent is further volatilized in the step of photocrosslinking the alignment layer compound by absorbing the UV.

In the method of manufacturing an alignment layer of the present invention, the solvent includes at least one of hexyl acetate, butyl cellosolve, methylethylketone, methanol, and toluene.

In another aspect, the present invention includes a first substrate, a pixel electrode positioned on the first substrate, a first alignment layer covering the pixel electrode, a second substrate facing the first substrate, and the first And a common electrode positioned on any one of the second substrates, a second alignment layer positioned inside the second substrate, and a liquid crystal layer positioned between the first and second alignment layers, wherein the first and second alignment layers At least one of the alignment layers includes a material having a repeating unit represented by the following formula, R is selected from an alkyl group of C1 ~ C30, m+n=1 (n≥m), m=0.1~0.5, It provides a liquid crystal display device, characterized in that n = 0.5 ~ 0.9.

The liquid crystal display device of the present invention may further include a first polarizing plate positioned on an outer surface of the first substrate and a second polarizing plate positioned between the second substrate and the second alignment layer.

The liquid crystal display device of the present invention is characterized in that it further comprises a patterned retarder 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 layer of polyacrylate capable of low-temperature firing, it is possible to minimize substrate deformation due to the alignment layer forming process. Accordingly, it is possible to provide a flexible display device without a problem of deformation of the substrate.

In addition, by providing an in-cell-pole type liquid crystal display device in which the upper polarizing plate is formed in the display panel, the viewing angle of the liquid crystal display device can be improved.

In addition, in the in-cell-pole type liquid crystal display device, an alignment layer capable of low-temperature firing is formed on the upper polarizing plate, thereby preventing damage to the upper polarizing plate due to the alignment layer forming process.

1 is a cross-sectional view of a general liquid crystal display device.
2 is a flow chart for explaining a conventional alignment layer forming process.
3 is a schematic plan view of a liquid crystal display device according to a first embodiment of the present invention.
4 is a cross-sectional view taken along line IV-IV of FIG. 3.
5 is a flow chart illustrating a process of forming an alignment layer according to 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 a viewing angle in a 3D liquid crystal display.

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

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.

3 and 4, the liquid crystal display device according to the first embodiment of the present invention includes a first substrate 101 and a second substrate 150 facing each other, and the first and second substrates. (101, 150) first and second alignment layers 140 and 160 disposed inside each of 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.

Inside the first substrate 101, a gate wiring 103 is formed along a first direction, and a data wiring 112 crossing the gate wiring 103 through the gate insulating layer 110 is a second Formed along the direction. The pixel region P is defined by the gate wiring 103 and the data wiring 112 crossing each other.

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

The thin film transistor Tr includes a gate electrode 105 formed on the first substrate 101 and a semiconductor layer (not shown) overlapping the gate electrode 105 through the gate insulating layer 110 And, a source electrode 114 and a drain electrode 116 spaced apart from each other on the semiconductor layer (not shown).

The gate electrode 105 is connected to the gate line 103, and the source electrode 114 is connected to the data line 112. The source electrode 114 is positioned to be 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 constitute a storage capacitor StgC. That is, the overlapped portion of the common wiring 107 becomes a first storage electrode, the overlapped portion of the drain electrode 116 becomes a second storage electrode, and a gate insulating layer between the first and second storage electrodes (110) becomes the dielectric layer.

On the first substrate 101, a common wiring 107 spaced parallel to the gate wiring 103 and an auxiliary common electrode 109a extending from the common wiring 107 parallel to the data wiring 112 , 109b) may be formed.

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

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

However, when 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.

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

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

The pixel electrodes 130 and the common electrodes 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. In FIG. 3, it is shown 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 long as the common electrode 132 is electrically connected to the common wiring 107, there is no limitation on the connection relationship.

Meanwhile, one of the pixel electrode 130 and the common electrode 132 is formed on the first protective layer 118 and has a plate shape, and the other is a fringe having a plate shape including an opening. It can have a field switching structure. 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.

Also, 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, since light leakage around the data line 112 is blocked, the width of the black matrix 152 formed on the second substrate 150 is minimized or the black matrix (152) can be omitted.

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

Inside the second substrate 150, the thin film transistor Tr and a black matrix 152 covering the gate wiring 103 and the data wiring 112 are formed, and the black matrix 152 is formed. Covering the overcoat layer 154 is formed. In addition, a second alignment layer 160 is formed on the overcoat layer 154. In this case, 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 arrangement of liquid crystal molecules in the liquid crystal layer 170 is performed by the first and second alignment layers 140 and 160. Is determined.

First and second polarizing plates 182 and 184 are positioned outside each of the first substrate 101 and the second substrate 150. 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 positioned under the first polarizing plate 182. Meanwhile, when the liquid crystal display device is of a reflective type, the backlight unit may be omitted.

In addition, when the liquid crystal display is used for 3D display, a patterned retarder may be positioned outside the second polarizing plate 184.

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

[Formula 4]

In Formula 4, R is selected from an alkyl group. For example, R may be selected from a C1~C30 alkyl group, and may be CH ₃ , C ₂ H ₅ or C ₄ H ₉ . In addition, m+n=1 (n≥m), m=0.1~0.5, n=0.5~0.9, preferably m=0.16, n=0.84. The molecular weight may be 50,000-200,000.

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

For example, when the first and second substrates 101 and 150 are flexible substrates such as plastic, the flexible substrate may be damaged at 230 degrees Celsius, which is a conventional alignment layer forming process temperature.

However, since the first and second alignment layers 140 and 160 in the present invention can be fired at a low temperature, the above-described problem can be prevented.

In the above, it has been described that the first and second substrates 101 and 150 are flexible substrates, but it goes without saying that a generally used glass substrate may be used.

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

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

Next, an alignment material layer is formed by coating an alignment material solution (PA) containing a compound represented by the following Formula 5 and a solvent on the overcoat layer 154. (ST110)

[Chemical Formula 5]

In Formula 5, R is selected from an alkyl group. For example, R may be selected from a C1~C30 alkyl group, and may be CH ₃ , C ₂ H ₅ or C ₄ H ₉ . In addition, m+n=1 (n≥m), m=0.1~0.5, n=0.5~0.9, preferably m=0.16, n=0.84.

In addition, the solvent is characterized in that the solvent has a boiling point or volatilization temperature lower than the temperature of the drying (baking) process to be performed later, or a material capable of absorbing light in the UV spectrum range of the UV irradiation process to be performed later. That is, after the solvent is volatilized in the drying process, it is additionally volatilized in the UV irradiation process.

For example, at least one of a cellosolve-based solvent, an acetate-based solvent, a ketone-based solvent, an alcohol-based solvent, and an 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 Formula 5 may have about 1 to 5% by weight of the total alignment solution, and the remainder may be a solvent.

The copolymer represented by Formula 5 can be obtained by the following synthesis example.

Synthesis example

1. Synthesis Example 1

2-methoxy-4-formyl phenyl methacrylate (MFPMA) (1.98g, 0.009mol), methyl methacrylate (MMA) (5.1g, 0.051mol), 2,2-dinitrile/-azoizomaslyanoy acid (AIBN) (0.065g), Dioxane (6ml) was put into a vial and purged with nitrogen for 10-12 minutes to remove oxygen. Then, the mixture was polymerized for 2.5 hours at 700 degrees Celsius. After cooling the reactor, the obtained material was dissolved in 20 ml of dioxane, and then precipitated in 7-8 times excess isopropyl alcohol. The precipitation process was repeated to purify and then dried to obtain a copolymer. (yield: 65~67%, intrinsic viscosity (chloroform): 0.30dl/g)

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

2. Synthesis Example 2

MFPMA (1.98g, 0.009mol), ethyl methacrylate (EMA) (5.81g, 0.051mol), 2,2-dinitrile/-azoizomaslyanoy acid (AIBN) (0.065g), dioxane (6ml) in a vial Then, oxygen was removed by purging with nitrogen for 10 to 12 minutes. Then, the mixture was polymerized for 2.5 hours at 700 degrees Celsius. After cooling the reactor, the obtained material was dissolved in 20 ml of dioxane, and then precipitated in 7-8 times excess isopropyl alcohol. The precipitation process was repeated to purify and then dried to obtain a copolymer. (yield: 65~67%, intrinsic viscosity (chloroform): 0.35dl/g)

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

3. Synthesis Example 3

MFPMA (1.98g, 0.009mol), butyl methacrylate (BMA) (7.24g, 0.051mol), 2,2-dinitrile/-azoizomaslyanoy acid (AIBN) (0.065g), dioxane (6ml) in a vial Then, oxygen was removed by purging with nitrogen for 10 to 12 minutes. Then, the mixture was polymerized for 2.5 hours at 700 degrees Celsius. After cooling the reactor, the obtained material was dissolved in 20 ml of dioxane, and then precipitated in 7-8 times excess isopropyl alcohol. The precipitation process was repeated to purify and then dried to obtain a copolymer. (yield: 67~69%, intrinsic viscosity (chloroform): 0.33dl/g)

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

Next, a drying process is performed on the coated alignment material layer. (ST120) The drying process may be performed for about 60 to 600 seconds under a temperature condition of about 20 to 150 degrees Celsius, and the solvent in the orientation solution is completely or partially removed by the drying process.

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

Next, by irradiating UV on the alignment material layer, photo-crosslinking of the material represented by Chemical Formula 5 is performed. Accordingly, a second alignment layer 160 including the polyacrylate compound of Formula 4 may be prepared.

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

In the case of a conventional alignment layer using polyimide, a firing process at a relatively high temperature of 230 degrees Celsius is required for the imidation reaction, and the flexible substrate is damaged due to such a high firing process.

However, as described above, since the alignment layer of the present invention is made of a polyacrylate compound capable of firing (or drying) at a relatively low temperature (20 to 150 degrees Celsius) and photocrosslinking proceeds by UV irradiation, it is at a high process temperature. Damage to components such as the substrate can be prevented.

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

As shown in FIG. 6, a liquid crystal display device according to a second exemplary embodiment of the present invention includes a first substrate 201 and a second substrate 250 facing each other, and the first and second substrates 201 and 201, respectively. 250) First and second alignment layers 240 and 260 positioned inside each, a first polarizing plate 282 positioned outside the first substrate 201, the second substrate 250 and the And a second polarizing plate 284 positioned between the second alignment layers 260 and a liquid crystal layer 270 positioned 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 light transmission axes of the first and second polarizing plates 282 and 284 are perpendicular to each other. Meanwhile, each of the first and second substrates 201 and 250 may be a glass substrate.

In addition, a patterned retarder may be included between the second polarizing plate 284 and the second substrate 250. When the patterned retarder is included, the liquid crystal display is used for 3D image display.

As such, a 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. In the case where the patterned retarder is formed between the second substrate 250 and the second polarizing plate 284 in the in-cell pole structure liquid crystal display, the distance between the display pixel and the pixel column of the patterned retarder decreases. The vertical viewing angle is improved.

That is, referring to FIGS. 7A and 7B showing the viewing angle in the 3D display device, when the upper polarizing plate pol and the patterned retarder PR are located on the outer surface of the second substrate SUB2, the patterned retarder Because the distance between (PR) and the display pixel increases, the viewing angle decreases. (Fig. 7a)

However, as shown in FIG. 7B, the upper polarizing plate pol and the patterned retarder PR are positioned between the first substrate SUB1 and the second substrate SUB2, more precisely, on the inner side of the second substrate SUB2. In this case, since the distance between the patterned retarder PR and the display pixel decreases, the viewing angle increases.

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

Referring back to FIG. 6, a gate wiring (103 in FIG. 3) is formed in a first direction inside the first substrate 201, and the gate wiring (in FIG. 3) is interposed by a gate insulating layer 210. The data line 212 crossing the 103 is formed along the second direction. The pixel area P is defined by the gate wiring 103 and the data wiring 212 crossing each other. In addition, a common line (107 in FIG. 3) spaced apart from the gate line and auxiliary common electrodes 209a and 209b extending parallel to the data line are formed therefrom.

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

The thin film transistor Tr overlaps with the gate electrode (105 in FIG. 3) formed on the first substrate 201 and the gate electrode (105 in FIG. 3) through the gate insulating layer 210 A semiconductor layer (not shown), and a source electrode (114 in FIG. 3) and a drain electrode (116 in FIG. 3) spaced apart from each other on the semiconductor layer (not shown).

The gate electrode (105 in FIG. 3) is connected to the gate line (103 in FIG. 3 ), and the source electrode (114 in FIG. 3) is connected to the data line 212. The source electrode (114 in FIG. 3) is positioned to be 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 to cover the data line 212 and the thin film transistor (Tr in FIG. 3), and the first protective layer 218 On the top, a second protective layer 224 is formed of an organic insulating material such as photoacrylic and having a flat surface.

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

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

The pixel electrode 230 is connected to the drain electrode (116 of FIG. 3) through the drain contact hole (119 of 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.

Inside the second substrate 250, a black matrix 252 covering the thin film transistor Tr, the gate wiring 103 in FIG. 3 and the data wiring 212 is formed, and each pixel region ( The color filter layer 256 is formed corresponding to P).

In addition, a patterned retarder 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 according to the second embodiment of the present invention has an in-cell-pole type structure.

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

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

Accordingly, damage to the flexible substrate due to the polyimide alignment layer requiring a conventional high-temperature process can be prevented.

In addition, the liquid crystal display according to the second exemplary embodiment of the present invention has an in-cell-pole structure and thus has an effect of improving a viewing angle in 3D image display. In such a structure, the second alignment layer 260 is formed on the patterned retarder 286 and the second polarizing plate 284 in a state in which the patterned retarder 286 and the second polarizing plate 284 are formed.

In the case of using a polyimide alignment layer requiring a conventional high-temperature firing process, a problem of lowering the contrast ratio due to damage to the polarizing plate or a cross-talk problem of a 3D image may occur due to damage to the patterned retarder. However, in the present invention, since a polyacrylate alignment film that can be fired under a temperature condition of 150 degrees Celsius or less is used, the above-described problem is prevented.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the following claims. You will understand that you can.

101, 201: first substrate 150, 250: second substrate
103: gate wiring 105: gate electrode
107: common wiring 109a, 109b, 209a, 209b: auxiliary common electrode
110, 210: gate insulating layer 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 layer 182, 282: first polarizing plate
184, 284: second polarizing plate 286: patterned retarder

Claims (12)

It has a repeating unit represented by the following formula, R is selected from the alkyl group of C1 ~ C30, m+n=1 (n≥m), m=0.1~0.5, n=0.5~0.9. Compound for alignment film.

Including a material having a repeating unit represented by the following formula, R is selected from the alkyl group of C1 ~ C30, m+n=1 (n≥m), m=0.1~0.5, n=0.5~0.9 Alignment film, characterized in that.

Forming an alignment material layer by coating an alignment material solution containing an alignment layer compound represented by the following formula and a solvent on a substrate;
Drying the alignment material layer;
Rubbing the alignment material layer;
Photocrosslinking the compound for the alignment layer by irradiating UV on the rubbed alignment material layer
Including,
R is selected from an alkyl group of C1 to C30, m+n=1 (n≥m), m=0.1 to 0.5, and n=0.5 to 0.9.

The method of claim 3,
The UV irradiation step is a method of manufacturing an alignment layer, characterized in that it proceeds under a dose condition of 2 ~ 10J/cm2.
The method of claim 3,
The drying step is a method of manufacturing an alignment layer, characterized in that it proceeds under a temperature condition of 20 to 150 degrees Celsius.
The method of claim 3,
The solvent has a volatilization temperature lower than the temperature in the drying step and is volatilized in the drying step.
The method of claim 6,
The solvent is further volatilized in the step of photocrosslinking the alignment layer compound by absorbing the UV.
The method according to claim 6 or 7,
The solvent is a method of manufacturing an alignment layer, characterized in that it contains at least one of hexyl acetate, butyl cellosolve, methylethylketone, methanol, and toluene.
A first substrate;
A pixel electrode on the first substrate;
A first alignment layer covering the pixel electrode;
A second substrate facing the first substrate;
A common electrode positioned on one of the first and second substrates;
A second alignment layer positioned inside the second substrate;
Including a liquid crystal layer positioned between the first and second alignment layers,
At least one of the first and second alignment layers includes a material having a repeating unit represented by the following formula, R is selected from an alkyl group of C1 to C30, and m+n=1 (n≥m), A liquid crystal display device, characterized in that m=0.1~0.5, n=0.5~0.9.

The method of claim 9,
A first polarizing plate positioned on an outer surface of the first substrate;
The liquid crystal display device further comprising a second polarizing plate positioned between the second substrate and the second alignment layer.
The method of claim 10,
And a patterned retarder positioned between the second substrate and the second polarizing plate.
The method of claim 9,
Wherein the first and second substrates are flexible substrates.

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