KR20040001112A - Liquid Crystal Cell for Liquid Crystal Display Device and Fabrication Method of The Same - Google Patents

Abstract

PURPOSE: A liquid crystal cell for a liquid crystal display and a method for manufacturing the same are provided to maintain the thickness of liquid crystal regardless of gravity, thereby preventing the quality of a picture from lowering. CONSTITUTION: A first substrate and a second substrate are separately arranged opposite to each other. A display area and a non-display area are defined on the first substrate and the second substrate. A seal pattern(125) is formed at an edge part between the first substrate and the second substrate. A functional polymer line(127) is formed inside the seal pattern and is made of a functional polymer heat-shrinkable at a high temperature. Liquid crystal(128) is interposed inside the functional polymer line between the first substrate and the second substrate.

Description

Liquid crystal cell for liquid crystal display device and manufacturing method therefor {Liquid Crystal Cell for Liquid Crystal Display Device and Fabrication Method of The Same}

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal cell for a liquid crystal display device and a manufacturing method thereof.

Recently, liquid crystal displays have been spotlighted as next generation advanced display devices having low power consumption, good portability, technology-intensive, and high added value.

In general, in order to use a liquid crystal for a display, a liquid crystal cell must be manufactured.

The liquid crystal cell has a structure in which a liquid crystal is filled between two glass substrates or a plastic substrate. A transparent electrode (common electrode, pixel electrode) is formed on the substrate so that voltage can be applied to the liquid crystal. The transparent electrode serves to control on / off by applying a voltage to the liquid crystal.

That is, the light transmission amount of the liquid crystal display device is controlled by the voltage applied to the transparent electrode, and displays characters / images by the optical shutter effect.

Among such liquid crystal display devices, an active matrix liquid crystal display device having a switching element capable of controlling voltage on / off for each pixel is attracting the most attention due to its excellent resolution and ability to implement video.

The liquid crystal display device uses a substrate that has undergone an array substrate manufacturing process for forming a switching element and a pixel electrode and a color filter substrate manufacturing process for forming a color filter and a common electrode, and a liquid crystal cell process between the two substrates. Completed through

Hereinafter, the liquid crystal panel which is a basic component of the liquid crystal display device manufactured by the liquid crystal cell process is demonstrated.

1 is a flowchart illustrating a liquid crystal process generally applied.

In the st1 step, the first substrate, which is an array substrate including the thin film transistor and the pixel electrode connected to the thin film transistor, and the second substrate including the color filter and the common electrode are initially cleaned, and then the first and second substrates are provided. to be.

The st2 step is a step of forming an alignment film on the first substrate.

Formation of the alignment layer includes the application and rubbing process of the polymer thin film, the thickness of the thin film should be uniformly applied, and rubbing should also be uniform.

The st3 step is a process of printing a seal pattern on the alignment layer. The seal pattern in the liquid crystal process forms a gap for injecting the liquid crystal, and serves to prevent leakage of the injected liquid crystal.

The st4 step is a process of dispersing a spacer, and has a function of making the cell gap of the first and second substrates uniform.

After the spacer spreading process is completed, the bonding process of the first substrate, which is a thin film transistor array substrate, and the second substrate, which is a color filter substrate, is performed (st5).

The st6 step is a process of cutting the liquid crystal cell manufactured in the st1 to st5 step into a unit cell.

In the initial manufacturing process of the liquid crystal display device, a liquid crystal is injected into several cells at the same time, and then a cell unit is cut. However, as the cell size increases, the liquid crystal is injected after cutting into unit cells.

Next, in the st7 step, the liquid crystal is interposed in the liquid crystal cell cut into each unit cell.

The liquid crystal cell which has passed all the above-mentioned steps is attached to the outer side of the liquid crystal cell selected through the quality inspection, respectively, and then connected to the driving circuit to complete the liquid crystal display device.

FIG. 2 illustrates a liquid crystal cell, in which first and second substrates 10 and 11 having a display area and a non-display area are disposed to face each other, and a display area and a non-display area of the first and second substrates 10 and 11. The seal pattern 25 is formed in the boundary edge between the display areas, and the liquid crystal layer 22 is interposed in the display area inside the seal pattern 25.

Herein, the displayed area is referred to as an active area 20, in which spacers 26 are dispersed to maintain a constant cell gap as described above. In addition, the injection hole of the seal pattern 25 is sealed by the sealing agent 23.

3A to 3C are cross-sectional views illustrating a change in cell gap when the liquid crystal panel is raised to a high temperature in a standing state, and for convenience of description, three spacers described above in FIG. 2 are arranged in the longitudinal direction in the substrate. As shown. In general, since the display screen is positioned to face the viewer, the manufactured liquid crystal display device is used upright.

In FIG. 3A, the first and second substrates 10 and 11 are disposed to face each other, and the first and second substrates 10 and 11 are bonded to each other by a seal pattern 25. The liquid crystal layer 22 is interposed therebetween, and illustrates a structure in which the plurality of spacers 26 are disposed in the liquid crystal layer 22 for the purpose of maintaining the first cell gap d1 constant.

However, as shown in FIG. 3B, the liquid crystal display including the active region has a second cell gap d2 which is a distance between the upper substrate and the lower substrate when the backlight of the liquid crystal display is overheated or the ambient temperature increases. This becomes larger than the first cell gap d1 in the original state. This is due to the thermal expansion coefficient difference between the liquid crystal 28, the spacer 26, and glass, which is a material of the first substrate and the second substrate. As a result, as shown in FIG. 3C, the liquid crystal 28 flows down in the direction of gravity at a high temperature such that the lower portion becomes the third cell gap d3. This phenomenon is called a gravity failure phenomenon, and thus the image quality characteristics are degraded.

4 illustrates a display screen due to a gravity failure. In the region A, the screen is brighter than the surroundings due to the liquid crystal flowing down as described above. This has a problem of degrading the reliability of the product by showing an uneven gray scale on the whole screen.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a liquid crystal display device and a method of manufacturing the same, which can prevent degradation of image quality by maintaining the thickness of the liquid crystal layer regardless of gravity.

1 is a process flowchart showing a conventional liquid crystal cell process for a liquid crystal display device step by step.

2 is a plan view of a liquid crystal panel for a conventional liquid crystal display device.

3A to 3C are cross-sectional views of a conventional liquid crystal panel for a liquid crystal display device, and show a step-by-step change of a cell gap at a high temperature in a state where the liquid crystal panel is upright.

4 is a plan view showing a poor image quality condition shown in a conventional liquid crystal panel for a liquid crystal display device.

5 is a plan view of a liquid crystal panel for a liquid crystal display device including a functional polymer line according to the present invention.

6 is a cross-sectional view of a liquid crystal panel for a liquid crystal display device including a functional polymer line according to the present invention.

7 is a process flowchart showing step by step the liquid crystal cell process for a liquid crystal display device according to the present invention.

<Description of Signs of Major Parts of Drawings>

125: seal pattern 126: spacer

127: functional polymer line 128: liquid crystal

d: cell gap

A: area showing functional polymer lines shrinking at high temperature

In order to achieve the above object, in the first aspect of the present invention, a display area and a non-display area constituting the periphery of the display area are defined, and the first and second substrates spaced apart from each other by a predetermined distance; A seal pattern positioned at an edge of the boundary area between the first and second substrates; A line located inside the seal pattern, wherein the material is a functional polymer line which is a functional polymer that undergoes heat shrinkage at a high temperature; A liquid crystal panel for a liquid crystal display device including a liquid crystal interposed inside the functional polymer line between the first and second substrates is provided.

The material constituting the functional polymer line is selected from any one of an acrylic resin or an epoxy resin of a novolac system, or a polyolefin compound family. do.

The polyolefin compound is selected from any one of polyethylene, polypropylene, and poly isobutylene, characterized in that a liquid crystal inlet is formed at one side of the seal pattern.

According to a second aspect of the present invention, there is provided a method of forming a seal pattern comprising: a seal pattern covering a display area of a first substrate and a boundary area between the non-display area, the display area and a non-display area forming a periphery of the display area; Forming a functional polymer having heat shrinkage at a high temperature on an inner edge of the seal pattern; Bonding the first substrate and the second substrate to each other; It provides a method for manufacturing a liquid crystal panel for a liquid crystal display device comprising the step of interposing a liquid crystal layer between the first and second substrates.

The liquid polymer layer is interposed through an injection hole of the seal pattern, and the functional polymer line is formed by any one of a scanning method, a seal dispense printing method, a screen printing method, and an inkjet printing method. Is located at an inner portion of the seal pattern, and is positioned at a boundary between the display area and the non-display area.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example

FIG. 5 illustrates a liquid crystal cell in which a functional polymer line is formed according to the present embodiment.

A first and second substrates 100 and 110 in which a display area and a non-display area forming a periphery of the display area are defined, and a seal pattern 125 positioned at an edge portion between the first and second substrates 100 and 110; The liquid crystal display includes a functional polymer line 127 formed around an inner portion adjacent to the seal pattern 125 and a liquid crystal layer 128 interposed in the functional polymer line 127 region.

In this case, the seal pattern and the functional polymer line 127 are positioned at the boundary between the display area and the non-display area of the first and second substrates 100 and 110, and serve to bond the first and second substrates 100 and 110. The functional polymer line 127 described above does not react with the liquid crystal 128, the spacer 126, or other organic materials, and has a property of shrinking in a high temperature state.

Possible materials can be selected from acrylic resins or novolac based epoxy resins and polyolefin compound families.

The polyolefin compound includes polyethylene, polypropylene, poly isobutylene, and the like, and in particular, poly isobutylene is mainly used.

The injection hole of the seal pattern 125 is sealed with an encapsulant 123.

As a method of forming the functional polymer line 127, a seal dispensing method and a seal printing method used in a seal pattern are possible, and another method is an inkjet method.

FIG. 6 is a cross-sectional view of the liquid crystal cell according to the present invention. First, the seal pattern 125 is formed in the outermost part of the liquid crystal cell, and the functional polymer line 127 is formed along the inside thereof. The liquid crystal 128 and the spacer 126 are formed in the seal pattern 125 and the functional polymer line 127.

However, when the liquid crystal cell expands at a high temperature, the functional polymer, which is a material of the functional polymer line, contracts like the region A due to its inherent characteristics, so that the liquid crystal cannot flow down. As a result, since the cell gap d is maintained as it is, as shown in FIG. 3A, the display screen can be produced with uniform and reliable products.

7 is a flowchart illustrating a process of manufacturing a liquid crystal cell according to the present invention.

In the step ST1, the first substrate, the array substrate including the thin film transistor and the pixel electrode connected to the thin film transistor, and the second substrate including the color filter and the common electrode are initially cleaned, and then the first and second substrates are provided. to be.

Next, in the step ST2, an alignment layer is coated on the first substrate, which is a thin film transistor array substrate, using a roller.

The reason for applying the alignment film is for uniform molecular alignment of the liquid crystal, and the coating method is a rotary coating method or a printing coating method. After applying the alignment layer on the substrate, it is cured and then rubbed. This may further increase the effect of uniform molecular arrangement by changing the microstructure of the alignment layer through rubbing.

In step ST3, an edge-shaped seal pattern is formed along the edge of the substrate on which the alignment layer is formed. The seal pattern includes an injection hole in addition to the edge shape, and the forming process is representative of screen printing and seal dispenser printing.

Next, in step ST4, a functional polymer line according to the present invention is formed. The functional polymer line is formed on the inner edge of the seal pattern, and the forming method may be formed by any one of a screen printing method, a seal dispenser printing method, and an inkjet printing method, such as a method of forming a seal pattern.

As described above, the functional polymer line may be an acrylic resin or a novolac-based epoxy resin which does not react with the liquid crystal and the seal pattern, but shrinks at a high temperature, and may be a polyolefin. ) Compound series are possible. Examples of the polyolefin compound series include polyethylene, polypropylene, poly isobutylene, and polyisobutylene is mainly used.

Next, ST5 is a step of dispersing the spacer. When the first substrate and the second substrate are bonded to each other, ST5 uniformly mixes the spacers in the solution and then sprays the upper portion of the alignment layer in order to secure a constant cell gap.

Next, in steps ST6 to ST8, the first and second substrates are bonded and cut, and then liquid crystal is interposed between the first and second substrates using capillary action and pressure difference.

In this way, the sealing agent is applied to the inlet of the seal pattern through the liquid crystal to prevent the inlet. Generally, a photocurable resin or a thermosetting resin is used.

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

As described above, according to the liquid crystal display device including the functional polymer line according to the present invention, the gravity defect can be minimized without changing the seal pattern and the material of the liquid crystal layer, thereby improving image quality characteristics.

Claims (9)

A display area and a non-display area forming a periphery of the display area are defined, First and second substrates spaced apart from each other and disposed to face each other; A seal pattern positioned at an edge of the boundary area between the first and second substrates; A line located inside the seal pattern, wherein the material is a functional polymer line which is a functional polymer that undergoes heat shrinkage at a high temperature; Liquid crystal interposed inside the functional polymer line between the first and second substrates Liquid crystal panel for a liquid crystal display device comprising a. The method of claim 1, The material constituting the functional polymer line is selected from any one of an acrylic resin (eprylic resin) or a novolak-based epoxy resin (epoxy resin) of the liquid crystal panel for a liquid crystal display device. The method of claim 1, The material forming the functional polymer line is a liquid crystal panel for a liquid crystal display device selected from the group of polyolefin compounds. The method of claim 3, wherein The polyolefin compound is a liquid crystal panel for a liquid crystal display device selected from any one of polyethylene (polyethylene), polypropylene (polypropylene), poly isobutylene (poly isobutylene). The method of claim 1, A liquid crystal panel for a liquid crystal display device having a liquid crystal injection hole formed on one side of the seal pattern. Forming a seal pattern covering the display area of the first substrate having a display area and a non-display area forming the periphery of the display area and a boundary area between the non-display area; Forming a functional polymer having heat shrinkage at a high temperature on an inner edge of the seal pattern; Bonding the first substrate and the second substrate to each other; Interposing a liquid crystal layer between the first and second substrates Method of manufacturing a liquid crystal panel for a liquid crystal display device comprising a. The method of claim 6, Method of manufacturing a liquid crystal panel for a liquid crystal display device via the liquid crystal layer in the injection method through the injection hole of the seal pattern. The method of claim 6, The functional polymer line is a manufacturing method of a liquid crystal panel for a liquid crystal display device, which is formed by any one of a scanning method, a seal dispense printing method, a screen printing method, and an inkjet printing method. The method of claim 6, Wherein the functional polymer line is positioned at an inner portion of the seal pattern and is positioned at a boundary between a display area and a non-display area.