KR100797095B1 - Liquid crystal display device with a ink jet spacer and method for fabricating the spacer - Google Patents

Abstract

An LCD(Liquid Crystal Display) having an inkjet spacer and a method for manufacturing the inkjet spacer are provided to prevent increase of a width of the spacer caused by blur of ink and easily implement a desired height by forming the inkjet spacer after forming partitions, so that reliable image display can be possible. First and second substrates(20,40) are disposed so as to face each other. An LC(Liquid Crystal) layer(10) is interposed between the two substrates. An inkjet spacer(50) is fixed on one substrate of the two substrates so as to maintain a cell gap between the two substrates. The inkjet spacer comprises a domed convex unit and a concave unit. The concave unit is recessed towards a center of a width direction from an end part of the convex unit as an inflection point. Partitions are formed on one substrate of the two substrates. The inkjet spacer is formed in an inner spacer of the partition. After that, the partitions are removed.

Description

Liquid crystal display device having an inkjet spacer and a manufacturing method of the spacer {LiQUID CRYSTAL DISPLAY DEVICE WITH A INK JET SPACER AND METHOD FOR FABRICATING THE SPACER}

1 is a schematic configuration diagram of a liquid crystal display device having an inkjet spacer according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the inkjet spacer shown in FIG. 1.

3 is a process block diagram illustrating a method of manufacturing an inkjet spacer according to an embodiment of the present invention.

FIG. 4 is a plan view showing a state after the partitioning ink drying and curing step shown in FIG. 3.

FIG. 5 is a side view showing a state after the ink dropping step for forming a spacer shown in FIG. 3.

The present invention relates to a liquid crystal display device having an inkjet spacer formed by an inkjet method, and a method of manufacturing the inkjet spacer.

Typically, the liquid crystal display includes first and second substrates facing each other with the liquid crystal layer interposed therebetween.

The first substrate includes a plurality of gate lines and data lines arranged vertically and horizontally to define pixels in a matrix form, thin film transistors formed at intersections thereof, and connected to the respective thin film transistors. A pixel electrode is provided.

The second substrate is provided with a color filter layer, a black matrix, a common electrode and the like.

The color filter layer includes a repetition of red, green, and blue color filters arranged to reflect light of a specific wavelength band in a state corresponding to each pixel of the first substrate.

The black matrix covers non-pixel regions such as gate lines, data lines, and thin film transistors of the first substrate, thereby corresponding to pixel regions, in particular, pixel electrodes, in which an image shown to an actual user is displayed according to a change in the arrangement of liquid crystal molecules. Expose the parts.

Here, the positions of the black matrix and the color filter layer may be changed. A seal pattern is formed at both edges of the substrate to prevent cell gap for liquid crystal injection, adhesion of both substrates, and leakage of liquid crystal. The boundary between the two substrates and the liquid crystal layer provides an initial alignment direction of the liquid crystal. First and second alignment films to be determined are interposed.

In the liquid crystal display device having such a configuration, the cell gap defined by the thickness of the liquid crystal layer, that is, the gap between the first and second substrates, for example, must be kept constant for reliable image representation. Is formed.

As a general spacer, a ball spacer which randomly distributes a spherical resin material between both substrates has been used.

While this requires a relatively simple process, the position cannot be fixed accurately, and thus light leakage may occur due to adsorption force with surrounding liquid crystal molecules.

In addition, there is a possibility of movement, which may cause scratches or the like on the alignment layer, and since the density distribution is not constant, reliability of the cell gap is poor when applied to a large area liquid crystal display. And for the same reason, if you touch the screen, a ripple phenomenon may appear for a while.

Due to this problem, a patterned spacer or a spacer using an inkjet method (hereinafter referred to as an “inkjet spacer”) that can be formed to be fixed at a desired position has been developed.

These patterned spacers and inkjet spacers can be limited to non-display regions, thereby preventing light leakage even when adsorptive forces with surrounding liquid crystal molecules occur, and precisely controlling the degree of compaction, thereby maintaining cell gaps. Reliability is prevented and ripple is prevented.

However, patterned spacers require photographic processes, including coating, exposure, development, and etching processes of organic materials, which are time consuming and costly, and impair other devices by the physical / chemical process described above. There is an easy disadvantage.

On the other hand, the inkjet spacer has an advantage that it can be completed through a relatively simple process of dropping a liquid organic material (hereinafter referred to as 'ink') in a non-pixel region and then curing with heat or ultraviolet rays.

However, this inkjet spacer also has some problems, and since the ink must have a certain degree or more of viscosity for dropping, it is used in a sol state close to a liquid dissolved in a suitable solvent. Therefore, the spreading width is very difficult to exactly match the desired height.

In addition, it is often observed that the ink dropped into the non-pixel region spreads and invades the pixel region, which in turn may deteriorate the image quality of the liquid crystal display device, which hinders the utilization of the inkjet spacer.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a liquid crystal display device having an inkjet spacer capable of preventing ink spreading and easily realizing a target height.

Another object of the present invention is to provide an effective method for producing an inkjet spacer.

The present invention to achieve the above object,

A first substrate and a second substrate disposed to face each other;

A liquid crystal layer provided between the substrates; And

Inkjet spacers fixed on either one of the substrates to maintain a cell gap between the substrates

Including;

The inkjet spacer provides a liquid crystal display including a hemispherical convex portion and a concave portion formed concave toward the center in the width direction with the end of the convex portion as an inflection point.

According to an embodiment of the present invention, the concave portion has a concave end portion fixed to either of the substrates.

The concave portion may be formed such that the width gradually decreases from the inflection point toward the concave end portion, or the width gradually decreases and then increases.

In this case, the concave end may have a width of 30 μm or less, preferably 20 μm or less.

The inflection point may be formed at a height within the range of H / 5 to 4H / 5 when H is an overall height of the inkjet spacer measured from the concave end.

Inkjet spacers of such a configuration,

Forming a partition having an inner space for forming a spacer on any one of the first and second substrates for a liquid crystal display;

Forming an inkjet spacer in an inner space of the partition wall; And

Removing the partition wall

It can be prepared according to.

Here, the forming of the partition wall,

Dropping the partition forming ink in an inkjet manner to form the inner space, and drying and curing the partition forming ink.

Here, the partitioning ink may be dropped at least four or more points to form an approximately circular inner space, and may be dried and cured with heat or ultraviolet rays.

The partition forming ink is preferably dropped to form an inner space having a width of approximately 30 µm or less, preferably 20 µm or less.

On the other hand, as the ink for forming the partition walls, polyvinyl alcohol, polyvinylpyridine, polyethylene oxide, polyacrylic acid, polybutadiene, polyisoprene, polyvinylchloride, polystyrene, polymethylmethacrylate, polylactic acid, polycaprolactam , Polycaprolactone, polyaceketone, polyacetate, polyacrylonitrile, polyoxyethylene, and the like can be used, but are not necessarily limited to the above materials.

The bulkhead forming ink can be easily removed by a solvent, and the solvent includes water, acetone, methanol, ethanol, isopropanol, propanol, butanol, sclohexanone, benzene, toluene, xylene, hexane, heptane, octane, Methyl ethyl ketone, chloroform, formaldehyde and the like can be used.

The forming of the inkjet spacer may include dropping the spacer forming ink into the inner space, and drying and curing the spacer forming ink.

Herein, conventional inks may be used as the ink for forming the spacer, and in order to facilitate injection, it is preferable to use a low viscosity ink of 50 cP or less.

On the other hand, the substrate to which the inkjet spacer is fixed can be subjected to hydrophilic or hydrophobic surface treatment, if necessary.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is a schematic configuration diagram of a liquid crystal display device having an inkjet spacer according to an embodiment of the present invention, FIG. 2 is an enlarged view of the inkjet spacer shown in FIG. 1, and FIG. 3 is an inkjet spacer according to an embodiment of the present invention. The process block diagram which shows the manufacturing method of this is shown.

4 is a plan view showing a state after the partitioning ink drying and curing step shown in FIG. 3, and FIG. 5 is a side view showing a state after the ink dropping step for spacer formation shown in FIG. 3.

A liquid crystal display device having an inkjet spacer according to an exemplary embodiment of the present invention includes a first substrate 20 and a second substrate 40 facing each other with the liquid crystal layer 10 therebetween.

A plurality of gate lines (not shown) and data lines 22 are formed on one surface of the first substrate 20 to be arranged horizontally and horizontally to define the pixels P in a matrix form, and these gate lines and data are formed. A thin film transistor T is formed at an intersection point of the line 22, and a pixel electrode 24 corresponding to each pixel is connected to each thin film transistor T.

The thin film transistor T includes a gate electrode 26 branched from a gate line, a source electrode 22a branched from a data line 22, a drain electrode 28 connected to the pixel electrode 24, and a charge. and an active channel layer 30 which is a carrier movement path such as an electron or a hole.

In FIG. 1, reference numeral 32 denotes a gate insulating film formed on the entire surface of the substrate therebetween for insulation of the gate line and the data line 22, and 34 denotes a gate insulating film for protecting the thin film transistor T. The protective film formed on the whole substrate upper part is shown.

FIG. 1 illustrates a bottom gate structure in which a gate electrode 26 is formed below a source electrode 22a and a drain electrode 28 as an example of a thin film transistor. It is also possible for the gate electrode to have a thin film transistor having a top gate structure formed on the source electrode and the drain electrode.

In addition, a color filter layer 42, a black matrix 44, and a common electrode 46 are formed on one surface of the second substrate 40.

The color filter layer 42 is composed of repetition of red, green, and blue color filters arranged to reflect light of a specific wavelength band in a state corresponding to each pixel P of the first substrate 20.

The black matrix 44 covers the non-pixel regions of the gate line and the data line 22 of the first substrate 20, the thin film transistor T, and the like, so that the black matrix 44 is provided to the actual user according to the change of the arrangement of the liquid crystal molecules. The pixel region in which the image to be displayed is displayed, in particular, the portion corresponding to the pixel electrode 24 is exposed.

The common electrode 46 is made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

Although not shown, the positions of the black matrix 44 and the color filter layer 42 may be changed. In addition, a seal pattern is formed at the edges of both substrates to maintain cell gap for liquid crystal injection and to prevent adhesion of the two substrates 20 and 40 and leakage of liquid crystal. First and second alignment layers (not shown) are formed at boundaries of the layer 10 to determine initial alignment directions of the liquid crystals, respectively.

Meanwhile, in order to express a reliable image in the above-described liquid crystal display device, the gap between the first and second substrates 20 and 40, that is, the cell gap defined by the thickness of the liquid crystal layer 10 is kept constant. To this end, in the embodiment of the present invention, the inkjet spacer 50 is formed between the two substrates.

As shown in FIG. 2, the ink jet spacer 50 is concave toward the center C in the width direction with the hemispherical convex portion 52 and the end of the convex portion 52 as the inflection point 54. It consists of a cross-sectional shape provided with the recessed part 56 used.

The concave portion 56 has a concave end portion 56a fixed on either of the substrates.

In the accompanying drawings, the inkjet spacer 50 is fixed on the second substrate 40, but it is also possible to fix the inkjet spacer 50 on the first substrate 20.

In addition, in the accompanying drawings, the width of the concave portion 56 gradually decreases from the inflection point 54 toward the concave end portion 56a, but the cross-sectional shape of the partition wall 60 shown in FIGS. 4 and 5 is shown. In some cases, the width may be gradually decreased and then increased.

In addition, the inflection point 54 may be formed at a height H 'within a range of H / 5 to 4H / 5 when the total height of the inkjet spacer 50 measured from the concave end 56a is H. Can be.

As described above, the cross-sectional shape of the concave portion 56 and the height adjustment of the inflection point 54 are used to adjust the cross-sectional shape of the partition wall 60 by performing hydrophilic or hydrophobic surface treatment on the second substrate 40. It is possible accordingly.

On the other hand, the ink jet spacer 50 has a width W of the concave end portion 56a of 30 µm or less, particularly 20 µm or less.

Hereinafter, the method of manufacturing the inkjet spacer 50 of the above structure is demonstrated.

The partition wall 60 is formed by dropping the partition wall ink on the second substrate 40 on which the color filter layer 42, the black matrix 44, and the common electrode 46 are formed.

As the ink for forming the barrier rib, polyvinyl alcohol, polyvinylpyridine, polyethylene oxide, polyacrylic acid, polybutadiene, polyisoprene, polyvinylchloride, polystyrene, polymethylmethacrylate, and polyether are easily removed by a solvent. Lactic acid, polycaprolactam, polycaprolactone, polyaceketone, polyacetate, polyacrylonitrile, polyoxyethylene and the like are used, but are not necessarily limited to the above materials.

At least four of the partition wall forming inks are formed as shown in FIG. 4 so as to form an inner space 62 for forming a spacer having a width of 30 µm or less, preferably 20 µm or less (see W in FIG. 2). It is dripped at the above point.

Subsequently, the partition wall 60 is formed by drying and curing the ink for partition wall formation using heat or ultraviolet rays.

After the partition 60 is formed, a spacer forming ink is dropped into the spacer forming inner space 62, and the ink for forming the spacer is dried and cured using heat or ultraviolet rays to form the inkjet spacer 50. .

In this case, as the ink for forming a spacer, a conventional one may be used.

For example, a spacer forming ink including a polymer emulsion, a curing initiator and an accelerator, a polymerizable compound having an unsaturated bond, a drying inhibitor, and a volatile solvent may be used, and the spacer forming ink may be dried and cured by heat or ultraviolet rays. When the volatile solvent evaporates, the size and height shrink.

In addition, it is preferable to use a low viscosity ink of 50 cP or less as the spacer forming ink.

After the inkjet spacer 50 is formed, the partition wall 60 is removed using a solvent.

In this case, water, acetone, methanol, ethanol, isopropanol, propanol, butanol, sclohexanone, benzene, toluene, xylene, hexane, heptane, octane, methyl ethyl ketone, chloroform, formaldehyde, etc. may be used. .

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it is within the scope of the present invention.

As described above, according to the exemplary embodiment of the present invention, by forming the inkjet spacer after the formation of the partition wall, an increase in the width of the spacer due to ink spreading can be prevented, and a target height can be easily realized.

Therefore, the liquid crystal display device having the inkjet spacers described above can be reliably represented.

Claims (14)

A first substrate and a second substrate disposed to face each other; A liquid crystal layer provided between the substrates; And Inkjet spacers fixed on either one of the substrates to maintain a cell gap between the substrates Including; The inkjet spacer includes a hemispherical convex portion and a concave portion formed concave toward the center in the width direction with the end of the convex portion as an inflection point. The method of claim 1, And the concave portion includes a concave end portion fixed to one of the two substrates. The method of claim 2, The concave end portion is formed in a width of 30㎛ or less. The method of claim 3, wherein And the inflection point is formed at a height within a range of H / 5 to 4H / 5 when H is an overall height of the inkjet spacer measured from the concave end. The method of claim 4, wherein And the concave portion gradually decreases in width from the inflection point toward the concave end portion. The method of claim 4, wherein The concave portion gradually decreases in width from the inflection point toward the concave end portion, and then increases. Forming a partition having an inner space for forming a spacer on any one of the first and second substrates for a liquid crystal display; Forming an inkjet spacer in an inner space of the partition wall; And Removing the partition wall; and The forming of the partition wall may include dropping the partition formation ink in an inkjet manner to form an inner space for forming the spacer, and drying and curing the partition formation ink. delete The method of claim 7, wherein A method of manufacturing an inkjet spacer, wherein the partition-forming ink is added dropwise to at least four points so as to form the inner space for forming the spacer in a circular shape. The method of claim 9, The manufacturing method of the inkjet spacer which drips the said partition formation ink so that the said inner space for spacer formation may have a width of 30 micrometers or less. The method of claim 7, wherein A method of manufacturing an inkjet spacer for drying and curing the partition forming ink with heat or ultraviolet rays. The method according to any one of claims 7 and 9 to 11, Examples of the barrier forming ink include polyvinyl alcohol, polyvinylpyridine, polyethylene oxide, polyacrylic acid, polybutadiene, polyisoprene, polyvinylchloride, polystyrene, polymethylmethacrylate, polylactic acid, polycaprolactam, and polycapro A method for producing an inkjet spacer using any one selected from lactones, polyaceketones, polyacetates, polyacrylonitrile, and polyoxyethylene. The method of claim 12, As a solvent for removing the bulkhead ink, water, acetone, methanol, ethanol, isopropanol, propanol, butanol, sclohexanone, benzene, toluene, xylene, hexane, heptane, octane, methyl ethyl ketone, chloroform and formaldehyde Method for producing an inkjet spacer using any one of the materials selected from. The method of claim 13, The forming of the inkjet spacer may include dropping the spacer forming ink into the inner space, and drying and curing the ink for forming the spacer.

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