KR100827964B1 - Multi-domain vertical alignment mode liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

According to the present invention, an electric field is formed between the first and second substrates facing each other, the first and second substrates having first and second electrodes formed therein, respectively, and interposed between the first and second substrates. In a vertical alignment liquid crystal display device comprising a vertically arranged liquid crystal layer and upper and lower vertical alignment layers positioned between the liquid crystal layer and the first and second electrodes, respectively, wherein the first and second electrodes are provided in corresponding regions. It is located, and by providing a multi-domain vertical alignment mode liquid crystal display device comprising a plurality of projections made by a film transfer method spaced apart from each other by a certain distance, the cost required for the process of manufacturing the projections can be reduced to improve the production yield Has

Description

Multi Domain Vertical Alignment Mode Liquid Crystal Display Device and Method of Fabricating the same             

1 is a three-dimensional view of a portion of a general liquid crystal display device.

2 is a plan view of one liquid crystal driver of a general MVA mode liquid crystal display device;

3A and 3B are cross-sectional views cut along the cutting line III-III of FIG. 2 according to electric field characteristics.

Figures 4a to 4c is a step showing each step of the manufacturing process of the projection for the conventional MVA mode liquid crystal display device.

5 is a plan view of one liquid crystal driver of the MVA mode liquid crystal display device according to the present invention;

Figure 6a, 6b is a step showing a projection manufacturing process using a film transfer method according to the present invention.

<Description of Symbols for Major Parts of Drawings>                 

110: protrusion Va: upper region

Vb: lower region V: liquid crystal driver

①, ②, ③, ④: 1st, 2nd, 3rd, 4th domain

The present invention relates to a liquid crystal display device, and more particularly, to a multi-domain vertical alignment mode liquid crystal display device.

The liquid crystal display device is most popular as a next generation advanced display device device having low power consumption, good portability, technology-intensive and high added value.

The driving principle of the liquid crystal display device is the optical and dielectric anisotropy of the liquid crystal. The liquid crystal has a long and thin structure, and thus has a directivity in the arrangement of molecules. The liquid crystal can be artificially applied to the liquid crystal to control the direction of the molecular arrangement. have.

Accordingly, if the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light is refracted in the molecular arrangement direction by optical anisotropy to express image information.

1 is a stereoscopic view of a part of a general liquid crystal display device.

As shown, the upper and lower substrates 10 and 30 are opposed to each other by a predetermined distance, and the liquid crystal layer 50 is interposed between the upper and lower substrates 10 and 30.

A plurality of gates and data lines 32 and 34 cross each other on the lower substrate 30, and a thin film transistor T is formed at a point where the gates and data lines 32 and 34 cross each other. A pixel electrode 46 connected to the thin film transistor T is formed in the pixel area P defined as an area where the gate and the data lines 32 and 34 intersect.

The color filter layer 12 and the common electrode 16 are sequentially formed below the upper substrate 10.

Although not shown in detail in the drawing, the color filter layer 12 is composed of a color filter for transmitting only light of a specific wavelength band and a black matrix positioned at a boundary of the color filter to block light on an area where the arrangement of liquid crystals is not controlled.

In addition, upper and lower polarizers 52 and 54 for transmitting only light parallel to the polarization axis are positioned on each outer surface of the upper and lower substrates 10 and 30, and a backlight, which is a separate light source, is provided below the lower polarizer 54. light) is placed.

The present invention relates to a liquid crystal display device using the dielectric anisotropy of the liquid crystal. Hereinafter, the liquid crystal alignment characteristics of the liquid crystal display device will be described.

In general, liquid crystal modes using dielectric anisotropy include voltage controlled birefringence (ECB), twisted nematic (TN), and guest-host (GH). A negative liquid crystal is used in which the dielectric anisotropy arranged in the direction perpendicular to the electric field is negative (Δε <0).

Among the ECB modes, the vertical alignment (VA) mode has a small change in the response time with respect to the gray scale voltage, and thus has a good response characteristic compared to the TN liquid crystal display device.

A general VA mode liquid crystal display device is composed of a negative liquid crystal interposed between two substrates having a vertical alignment layer coated on an inner surface thereof, and a retardation plate may be separately provided on a lower surface of the substrate. As the vertical alignment layer, a method of depositing silane, chromium complex, or the like on a substrate and vertically aligning the liquid crystal molecules is generally used. In these cases, alkyle groups are arranged vertically on the substrate, and the liquid crystal molecules are oriented vertically by the interaction of the alkyl groups and the end groups of the liquid crystal molecules.

Recently, research / development has been actively conducted for a multi-domain VA mode (hereinafter, abbreviated as MVA) for providing a VA mode liquid crystal display device having improved viewing angle characteristics. In the early MVA mode liquid crystal display, a method of rubbing the vertical alignment layer in various directions by a photolithography process, which is a series of processes including exposure, development, and etching processes, has been proposed, but defects occur in the vertical alignment layer during the photolithography process. Etc., there is a disadvantage in falling product yield.

Accordingly, in recent years, an MVA mode liquid crystal display including a protrusion made of a dielectric material which causes an electric field distortion phenomenon on the upper and lower pixel areas to induce different alignment directions of liquid crystals has been proposed.

In more detail, in the MVA mode liquid crystal display having protrusions, the liquid crystal molecules are oriented perpendicular to the substrate under the influence of the vertical alignment layer in the voltage-off state, and when the voltage above the threshold is applied, the liquid crystal molecules are vertically aligned by the foreground lines generated near the protrusions. The liquid crystals are aligned in different directions with respect to the protrusions to form a multi-domain structure.

FIG. 2 is a plan view of one liquid crystal driving unit of a general MVA mode liquid crystal display, and is a plan view showing a protrusion pattern structure in a bonded substrate including liquid crystal, and hereinafter, a liquid crystal driving region between common electrodes facing one pixel electrode; It demonstrates by defining with a liquid crystal driver.

As illustrated, the liquid crystal driver II includes upper and lower regions IIa and IIb, and a plurality of protrusions forming a comb-toothed structure in a symmetrical direction at the boundary of the upper and lower regions IIa and IIb. 60 is formed.

At this time, each of the protrusions 60 adjacent to each other corresponds to the protrusions 60 formed on different substrates, and the protrusions 60 at positions dividing each of the regions IIa and IIb in a diagonal direction have two regions. By dividing into domains, the liquid crystal drive unit II is composed of four domains (1), (2), (3) and (4).

Next, the domain division characteristic by the electric field distortion phenomenon in the said projection part is demonstrated.

3A and 3B are cross-sectional views taken along the cutting line III-III of FIG. 2, and FIG. 3A illustrates the alignment characteristics of the liquid crystal when the dielectric constant of the protrusion is smaller than that of the liquid crystal, and FIG. 3B is a protrusion. When the dielectric constant of is larger than that of the liquid crystal, the orientation characteristic of the liquid crystal is shown.

In FIG. 3A, in the structure in which the upper and lower substrates 70 and 80 with the liquid crystal layer 90 interposed therebetween, the respective inner surfaces of the upper and lower substrates 70 and 80 are located in regions that are not corresponding to each other. The protrusion part 60 is formed. That is, the protrusions 60 are positioned at the center of the upper substrate 70, and the protrusions 60 are positioned at the left and right sides of the lower substrate 80, respectively.

At this time, as an example, when the material constituting the protrusions 60 is selected from a material having a smaller dielectric constant than the liquid crystal molecules 92, the electric field 94 indicated by the arrow is formed toward the outside of the protrusions 60 of the upper substrate 70. The liquid crystal molecules 92 are arranged in a direction perpendicular to the electric field 94, so that the liquid crystal arrays are divided into first and second domains (1, 2 in FIG. 2) having different liquid crystal arrays.

In FIG. 3B, as the material of the protrusions 60 is selected from a material having a higher dielectric constant than that of the liquid crystal molecules 92, the electric field 96 indicated by the arrow is directed toward the protrusions 60 of the upper substrate 70. The liquid crystal molecules 92 are formed in a direction perpendicular to the electric field 96.

In addition, the degree of electric field distortion becomes stronger as the dielectric constant difference between the protrusion 60 and the liquid crystal molecules 92 becomes stronger, and as the material of the protrusion 60 is selected from a material having a large dielectric constant difference between the liquid crystal molecules 92 and more stable, You can configure the domain structure.

4A to 4C are diagrams each illustrating a manufacturing process of a projection for a conventional MVA mode liquid crystal display, step by step.

4A is a step of coating a dielectric material layer 74 on a substrate 72.

In this step, the protrusion pattern portion IV is defined in the substrate 72.

The dielectric material layer 74 is selected from a negative type photosensitive dielectric material in which a portion exposed by light is patterned.

FIG. 4B shows a mask 78 having an open region 76 at a position corresponding to the protrusion pattern portion IV on the substrate 72 coated with the dielectric material layer 74, and then subjected to exposure treatment. Step.

In FIG. 4C, the protrusion 60 is formed on a region corresponding to the protrusion pattern portion IV by developing and etching the dielectric material layer 74 of FIG. 4B.

Although not shown in the drawings, after forming the protrusions, a step of forming a vertical alignment layer on the entire surface of the substrate on which the protrusions are formed is performed.

As described above, since the projection portion for the MVA mode liquid crystal display is formed by a photolithography process in which physical and chemical processes are repeated many times, the consumption of the projection material is large, the process cost is high, the process time is long, and the waste liquid after the etching process is There was a disadvantage in that the processing cost was added.

In order to solve this problem, an object of the present invention is to provide an MVA liquid crystal display device with improved production yield by reducing the cost and time required to form a projection for the MVA liquid crystal display device.

To this end, in the present invention, to form a projection by using a film transfer method.

The film transfer method is a method in which a film layer heated instantly using a laser is transferred to a substrate to be produced, and a process can be simplified as compared with a conventional photolithography process.

Although such a film transfer method is used in the color filter manufacturing process, it cannot be found in any literature used in the manufacturing process of the projection part for MVA mode liquid crystal display devices.

In order to achieve the above object, in one feature of the present invention, the first and second substrates facing each other and having first and second electrodes formed therein are respectively interposed between the first and second substrates. In the vertical alignment mode liquid crystal display device comprising a liquid crystal layer arranged perpendicular to an electric field formed between the first and second electrodes, and upper and lower vertical alignment layers respectively positioned between the liquid crystal layer and the first and second electrodes. The present invention provides a multi-domain vertical alignment mode liquid crystal display device including a plurality of protrusions positioned in regions corresponding to first and second electrodes and spaced apart from each other by a film transfer method.

The material forming the protrusions may be any one of photosensitive acrylic and BCB, and the protrusions may have a comb pattern structure.                     

In another aspect of the invention, there is provided a method comprising the steps of: providing a substrate; Providing a film transfer device including a laser device; Attaching a dielectric material film having a protrusion pattern on the substrate; A method of manufacturing a protrusion for a multi-domain vertical alignment mode liquid crystal display device comprising irradiating a laser onto a substrate on which the dielectric material film is attached and transferring the protrusion pattern onto a substrate.

The dielectric material film is characterized in that it is made of any one of photosensitive acrylic, BCB.

Hereinafter, a liquid crystal display substrate and a manufacturing method thereof according to the present invention will be described with reference to the drawings.

FIG. 5 is a plan view of one liquid crystal driving unit of the MVA mode liquid crystal display according to the present invention, and is illustrated mainly with the projection pattern structure of the bonded substrate including the liquid crystal.

As shown in the figure, in the liquid crystal drive unit V including the upper and lower regions Va and Vb, a comb-toothed structure is spaced apart from each other at regular intervals in a symmetrical direction with respect to the boundary between the two regions Va and Vb. A plurality of protrusions 110 forming the.

In this case, the protrusions 110 adjacent to each other are located on different substrates. In the upper and lower regions Va and Vb, the protrusions 110 positioned in the center in the diagonal direction, respectively, are divided into two domains divided by the protrusions 110 into domains having different alignment directions of the liquid crystals. , ②, ③, ④).

In the present invention, the protrusion 110 is formed by a film transfer method, the material forming the protrusion 110 is selected from a dielectric material, especially in order to stabilize the multi-domain structure has a large dielectric constant difference between the liquid crystal molecules It is preferred to be selected from materials.

Although not shown in the drawings, the present invention further includes a negative liquid crystal mode arranged perpendicular to the electric field direction. In the present invention, the pattern structure of the protrusion 110 is not limited to the above embodiment, but may be variously changed, and thus the number of multidomains is not limited.

6A and 6B are diagrams illustrating step-by-step manufacturing processes of the projection part using the film transfer method according to the present invention.

In FIG. 6A, after the film transfer device including the substrate 120 and the laser device such as an ultraviolet lamp is provided, the dielectric material film 122 is attached onto the substrate 120. In this case, the protrusion pattern part VI is defined in the dielectric material film 122.

The material constituting the dielectric material film 122 is preferably selected from materials having a large difference in dielectric constant from liquid crystal molecules, and more preferably selected from photo acryl and benzocyclobutene (BCB).

In FIG. 6B, a laser is irradiated onto the substrate 120 to which the dielectric material film 122 is attached, and the protrusion pattern portion IV of the dielectric material film 122 is transferred onto the substrate 120 by laser energy. After that, the protrusion 110 is formed by removing the remaining dielectric material film 122 from the substrate in the direction of the arrow.

Although not shown in the drawings, the dielectric material film 122 may be composed of a dielectric material layer, a light to hit conversion layer (LTHC) layer, and a base substrate, wherein the LTHC layer is a material that emits heat by laser energy. Is done. In this case, a separate adhesion layer may be further included between the substrate 120 and the dielectric material film 122, which may be included in the dielectric material film 122 or the dielectric material film 122 and the substrate. Prior to attachment of the 120, it may be formed on the substrate 120. The transfer of the dielectric material film 122 onto the substrate 120 may be performed by the exothermic action by the above-described LTHC layer.

In addition, the forming of the protrusion 110 may be followed by applying a vertical alignment layer on the substrate on which the protrusion 110 is formed.

However, the present invention is not limited to the above embodiments, and various modifications may be made without departing from the spirit of the present invention.

As such, when the protrusions are formed by the film transfer method according to the present invention, it is possible to minimize the process time and cost required for manufacturing the protrusions, thereby providing an MVA mode liquid crystal display device having improved production yield.

Claims (6)

Opposed to each other, interposed between the first and second substrates having the first and second electrodes formed therein, and the first and second substrates, and arranged perpendicularly to an electric field formed between the first and second electrodes. In the vertical alignment mode liquid crystal display device comprising a liquid crystal layer and upper and lower vertical alignment layers respectively positioned between the liquid crystal layer and the first and second electrodes, A plurality of protrusions positioned in regions corresponding to the first and second electrodes and formed by a film transfer method spaced apart from each other by an adhesive layer on inner surfaces of the first and second substrates. Multi-domain vertical alignment mode liquid crystal display comprising a. The method of claim 1, The material forming the protrusions may be any one of photosensitive acrylic and BCB. The method of claim 1, The projection portion has a multi-domain vertical alignment mode liquid crystal display device having a comb pattern structure. Providing a substrate; Providing a film transfer device including a laser device; Attaching a dielectric material film having a protrusion pattern on the substrate; Irradiating a laser onto the substrate to which the dielectric material film is attached, and transferring the protrusion pattern onto the substrate. Method of manufacturing a projection for a multi-domain vertical alignment mode liquid crystal display comprising a. The method of claim 4, wherein The dielectric material film is a method of manufacturing a projection for a multi-domain vertical alignment mode liquid crystal display device made of any one of photosensitive acrylic, BCB. The method of claim 4, wherein A method for manufacturing a projection for a multi-domain vertical alignment mode liquid crystal display device having an adhesive layer interposed between the substrate and the dielectric material film.

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