JP2001337331A - Liquid crystal display device and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device which can realize reduction of the manufacturing time and has uniform distance between substrates, and its production method, in the liquid crystal display device having a sealing part arranged in a closed frame shape. SOLUTION: The liquid crystal display device 100 is provided with first and second substrate 200 and 300, a liquid crystal layer 500 arranged between these substrates 200 and 300, a sealing part 400 of a frame shape which is arranged between the substrates 200 and 300, and surrounds a liquid crystal layer 500, and a spacer 213 which maintains the gap between the first and second substrate 200 and 300. The spacer 213 is formed integrally with at least one substrate of the first and second substrate 200 and 300, and is formed in an ununiform state of substrate intra-plane density.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a liquid crystal display device having a spacer for holding a space between substrates and a method of manufacturing the same.

[0002]

2. Description of the Related Art A flat display device represented by a liquid crystal display device is utilized in various fields by utilizing its features of thinness, light weight, and low power consumption. Taking an active matrix type liquid crystal display device as an example, an array substrate, a counter substrate disposed to face the array substrate, a liquid crystal layer held between the pair of substrates, and a And a seal portion arranged in a frame shape around the liquid crystal layer.
Conventionally, in such a method of manufacturing a liquid crystal display device,
After manufacturing a cell having an inlet formed by opening a part of a seal portion, a method of evacuating the inside of the cell and injecting a liquid crystal was generally used. However, in such a manufacturing method, the lead time is very long due to the necessity of evacuating the inside of the cell, and the productivity is impaired.

[0003]

Problems to be Solved by the Invention Japanese Patent Laid-Open No. 6-19461
Japanese Patent Application Laid-Open No. 5-53139 discloses a technique in which a ferroelectric liquid crystal is dropped on a substrate provided with a frame-shaped sealing material located on the outer periphery of a frame-shaped spacer. In other words, in injecting the liquid crystal into the cell, the liquid crystal is dropped on one substrate, and then the other substrate is superimposed to form a liquid crystal cell. Have been. According to such a manufacturing method, the conventional evacuation can be eliminated, and as a result, the productivity can be improved. An object of the present invention is to further improve the above-described drop injection method, and to provide a liquid crystal display device in which the distance between substrates is uniform and the manufacturing time is further reduced, and a method of manufacturing the same. I have.

[0004]

According to the first aspect of the present invention,
A first and a second substrate, a liquid crystal layer disposed between the substrates, a frame-shaped sealing portion disposed between the substrates and surrounding the liquid crystal layer; A spacer for maintaining a gap, wherein the spacer is formed integrally with at least one of the first and second substrates and has a non-uniform substrate in-plane density. Is to do. According to a third aspect of the present invention, there is provided the first and second substrates, a liquid crystal layer disposed between the substrates, and a frame-shaped sealing portion disposed between the substrates and surrounding the liquid crystal layer. A spacer for maintaining a gap between the first and second substrates, wherein the spacer is integrated with at least one of the first and second substrates and in a plane of the substrate. A step of applying a sealing material to at least one of the substrates while unevenly disposing the spacers, a step of dropping liquid crystal inside the sealing material of the one substrate to which the sealing material is applied, and A step of superposing the first and second substrates via the spacer and the sealing material, and a step of forming a sealing portion by pressing the first and second substrates and curing the sealing material. It is characterized by having a and.

According to the present invention, the liquid crystal is injected by dropping, and the spacers formed integrally with the substrate are arranged so as to be unevenly distributed in the surface of the substrate. The time is greatly reduced, and the liquid crystal can be injected uniformly in the plane.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. 1 is a schematic perspective view of the liquid crystal display device, and FIG. 2 is a partial schematic cross-sectional view taken along line AA in FIG. As shown in FIG. 2, the liquid crystal display device 100 of this embodiment includes an array substrate 200 and an array substrate 20.
0, and a TN (Tw) sandwiched between the substrates 200 and 300 via an alignment film.
A liquid crystal layer 500 made of isted nematic) liquid crystal, and a spacer 213 integrally formed on an array substrate that keeps the distance between the substrates constant, for example, 5.2 μm. Also, as shown in FIG. 1, two substrates 200,
Reference numeral 300 is sealed by a seal portion 400 arranged in a rectangular frame shape surrounding the display area. The array substrate 200
A signal line 210 disposed substantially in parallel at equal intervals on a transparent insulating substrate 201, a scanning line disposed substantially orthogonal to the signal line 210 via an interlayer insulating layer 208, and a thin film transistor (TFT) disposed at each intersection thereof ; Thin Film
Transistor) and the pixel electrode 2 connected thereto
14. The detailed structure will be described below with reference to FIG. 2. The channel region 20 disposed on a transparent insulating substrate 201 made of glass with an underlayer 202 interposed therebetween.
7, a coplanar polysilicon comprising a polysilicon layer including source and drain regions 205 and 206, a gate insulating film 203 formed so as to cover them, and a gate electrode 204 disposed on the gate insulating film 203. TF
T is configured. Further, a source electrode 209 and a signal line 210 which are electrically connected to the source and drain regions 205 and 206 through contact holes formed in the gate insulating film 203 and the interlayer insulating layer 208 are arranged. On top of this, via an insulating layer 211,
R, G, and B colored layers 212 are formed.
2 on top of ITO (Indium Tin Oxide)
A pixel electrode 214 composed of
Reference numeral 4 is electrically connected to the source electrode 209 via contact holes formed in the insulating layer 211 and the coloring layer 212. A columnar spacer 213 is formed in a region between the pixel electrodes on the coloring layer 212, and the columnar spacer 21 is formed.
3, an alignment film 215 is provided on the entire surface of the substrate so as to cover the pixel electrode 214 and the coloring layer 212.

On the other hand, an opposing substrate 300 disposed opposite to the array substrate 200 is configured such that an opposing electrode 302 and an alignment film 303 are disposed on a transparent insulating substrate 301. Next, the columnar spacers 21 formed on the array substrate 200
3 will be described in detail. 3 (a) is a schematic plan view of the array substrate, FIG. 3 (b) is an enlarged view of a region surrounded by a circle B in FIG. 3 (a), and FIG. 3 (c) is a circle C in FIG. FIG. 3 shows an enlarged view of an enclosed area. Conventionally, columnar spacers have been arranged uniformly within the seal in an ambassador to support atmospheric pressure, with a minimum required range, for example, 2000-3000 μm ² / mm ² .
On the other hand, in this embodiment, as shown in FIG. 3, the arrangement of the columnar spacers 213 is such that the density is 4000 μm ² / mm ² near the liquid crystal dropping position 501 and the liquid crystal dropping position 50 is high.
As the distance increases, the density decreases, 1000 μm ² / mm
² and the columnar spacers 213 are provided at different densities depending on the position in the substrate plane. As described above, the columnar spacers 213 are unevenly arranged, and the columnar spacers are installed under optimum conditions in accordance with the spreading speed of the liquid crystal. The columnar spacer 213 has a streamlined cross section parallel to the array substrate 200. The columnar spacer 213 has an elliptical shape with a major axis of 30 μm and a minor axis of 20 μm, and a columnar shape of 5.2 μm in height. The major axis of the elliptical shape is arranged substantially radially with the drop position 501 as the center.

By arranging the columnar spacers 213 having different in-plane densities radially thinner as the distance from the drop position 501 increases, the spread speed of the liquid crystal around the substrate is particularly prevented from being reduced. Uniform injection can be achieved in a shorter time. In addition, the columnar spacer 2
The cross-sectional shape of 13 is not limited to the above shape, and may be any shape as long as the liquid crystal does not hinder its movement when spreading. For example, FIG. 4 shows an example of a cross-sectional shape of a columnar spacer. FIG. 4C shows an elliptical shape according to the present embodiment.
As other cross-sectional shapes, the elliptical shape in FIG. 4C is deformed to form a streamline shape as shown in FIGS.
And a polygon such as a hexagon in (e).
Also, a streamline shape in which a part of the curvature circle is opposed via a rectangular parallelepiped as shown in FIG. In any case, the shape is such that the spreading direction of the liquid crystal is not hindered. As described above, according to the present invention, by setting the cross-sectional shape of the spacer to a streamline shape, a liquid crystal display device with good display quality without liquid crystal injection unevenness can be obtained. In addition, since the spacers are formed integrally with the array substrate, the spacers do not move with respect to the spread of the liquid crystal, thereby achieving excellent uniformity of the in-plane substrate spacing, improving the manufacturing yield, and improving over a long period of time. Reliability can be ensured.

[0009] Such a spacer 213 is formed as follows. The entire surface of the substrate, here the colored layer 21
2 Apply black resist on the entire surface using a spinner,
After drying at 80 ° C for 2 minutes, using a predetermined photomask,
Exposure is performed at a wavelength of 365 nm and an exposure amount of 250 mJ / cm ² . After this, TMAH (trimethyl ammonium hydrid
e) Developing with an aqueous solution for 60 seconds and baking at 220 ° C. for 60 minutes to form a 5.2 μm-thick and uniform spacer. Next, a pixel electrode 214 connected to the source electrode 209 through an opening formed in the coloring layer 212 and the insulating layer 211 is formed, and then the columnar spacer 213 and the pixel electrode 2 are formed.
14. An alignment film 215 is provided so as to cover the coloring layer 212,
The array substrate 200 is formed. On the other hand, the opposite substrate 300
Is formed by sequentially forming a counter electrode 302 and an alignment film 303 on a transparent substrate 301 such as glass. Thereafter, as shown in FIG. 1, a seal material which is cured by ultraviolet rays is applied to the array substrate 200 on which the alignment process has been completed, using a dispenser or a mask pattern. At this time, the sealing material is applied along the outer periphery of the display area in a closed system having no opening in a frame shape, here a rectangular shape.

Next, liquid crystal having the same volume as the cell volume is dropped on a plurality of locations on the substrate 200 coated with the sealing material.
00 is superimposed. The positions of the two substrates 200 and 300 are accurately aligned, and ultraviolet light is irradiated to temporarily fix the two substrates 200 and 300 so that the two substrates 200 and 300 do not shift. Such a superposition step is performed in a vacuum of about 1330 Pa.
Therefore, even if bubbles are generated in the cells, they are vacuum bubbles and can be absorbed by reorientation annealing in a subsequent step. Temporarily fixed two glass substrates 20
Pressing 0, 300 in the air to maintain a desired substrate interval, irradiating ultraviolet light, curing the sealing material,
The seal part 400 is formed. By placing cells stacked in vacuum in the atmosphere, 1 kg
Press at f / cm ² . During the pressing, the liquid crystal display device 10 may be pressurized as needed, and the liquid crystal display device 10 in which the spread liquid crystal is crushed by the counter substrate 300 and uniformly distributed.
0 is formed. In other words, near the liquid crystal dropping position, the liquid crystal spreads at a high speed, and as it moves away from the liquid crystal dropping position, the spreading speed decreases.However, at positions far from the liquid crystal dropping position, the spacers are formed at a low density and the liquid crystal spreading speed is adjusted. By doing so, it is possible to suppress liquid crystal injection unevenness and realize a liquid crystal display device having excellent display quality.

[0011] Further, according to such a manufacturing method, it is possible to reduce the cost of the apparatus and to greatly reduce the lead time required for manufacturing. In the above embodiment, the array substrate 20
Although the spacer 213 is fixedly arranged on the substrate 0 and the sealing material is applied, the spacer 213 and the sealing material may be arranged or applied on either the array substrate or the counter substrate, respectively. For example, a spacer may be arranged on one of the two substrates and a sealing material may be applied on the other, and there is no particular limitation. Further, as the sealing material, a material that cures with ultraviolet light is used, but a material that cures with heat may be used,
In this case, it may be cured by pressing and heating. In the above-described embodiment, a liquid crystal display device in which a counter electrode and a pixel electrode are formed as display patterns on two transparent insulating substrates, respectively, is used.
As in the ing) mode, the present invention can be applied to a liquid crystal display device in which a counter electrode and a pixel electrode are arranged on one substrate as a display electrode pattern. Further, in the above-described embodiment, the description has been made by using polysilicon for the semiconductor layer of the TFT. However, a TFT using amorphous silicon for the semiconductor layer may be used, and the structure thereof is not limited, for example, an inverted staggered type.

[0012]

According to the present invention, by forming a spacer having a non-uniform in-plane density integrally with a substrate, a liquid crystal display device having improved productivity and excellent display quality can be obtained. .

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a liquid crystal display device according to one embodiment of the present invention.

FIG. 2 is a partial schematic cross-sectional view taken along the line AA in FIG.

FIGS. 3A and 3B show an array substrate of the present invention. FIG. 3A is a schematic plan view, and FIG. 3B is a part of a region surrounded by a circle B in FIG. It is a partially enlarged schematic plan view in which
FIG. 3C is a partially enlarged schematic plan view in which a part of a region C in FIG.

FIGS. 4A to 4F are cross-sectional views of individual spacers of the present invention cut along a plane parallel to a substrate.

[Explanation of symbols]

 100: liquid crystal display device 200: array substrate 300: counter substrate 500: liquid crystal layer 400: seal portion 213: spacer

Claims (7)

[Claims] A first and a second substrate, a liquid crystal layer disposed between the substrates, a frame-shaped sealing portion disposed between the substrates and surrounding the liquid crystal layer; A spacer for maintaining a gap between the second substrates, wherein the spacers are integrated with at least one of the first and second substrates, and
A liquid crystal display device wherein the in-plane density of the substrate is formed non-uniformly. 2. The liquid crystal display device according to claim 1, wherein a cross-sectional shape of the spacer in a plane parallel to the first substrate is streamlined. 3. A first and a second substrate, a liquid crystal layer disposed between the substrates, a frame-shaped sealing portion disposed between the substrates and surrounding the liquid crystal layer, the first and second substrates, A method of manufacturing a liquid crystal display device, comprising: a spacer for maintaining a gap between second substrates; and a spacer which is integrated with at least one of the first and second substrates and is non-uniform in a substrate plane. Installing a seal material on at least one substrate; dropping liquid crystal inside the seal material of the one substrate to which the seal material has been applied;
And a step of superimposing the second substrate with the spacer and the sealing material therebetween, and a step of forming the sealing portion by pressing the first and second substrates and curing the sealing material. A method for manufacturing a liquid crystal display device, comprising: 4. The method for manufacturing a liquid crystal display device according to claim 3, wherein the spacers are arranged so that the density decreases as the distance from the position at which the liquid crystal is dropped. 5. The spacer according to claim 3, wherein the spacer is radially distributed around a position where the liquid crystal is dropped.
The manufacturing method of the liquid crystal display device according to the above. 6. The method for manufacturing a liquid crystal display device according to claim 4, wherein a cross-sectional shape of the spacer parallel to the substrate is a streamline type. 7. The method according to claim 3, wherein in the step of dropping the liquid crystal, the liquid crystal is dropped at a plurality of locations.