JP2002148636A - Liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an opening ratio and precision of a gap and to smoothly carry out fine adjustment of positioning of both substrates in sticking a pair of the substrates to each other. SOLUTION: A spacer 30 consists of a columnar backup spacer 31 composed of a resin arranged on an upper surface of an alignment layer 25 of the active substrate 21 and a spherical or cylindrical main spacer 32 composed of silica glass or a glass fiber arranged inside the backup spacer 31. The diameter of the main spacer 32 is set to be larger than the height of the backup spacer 31. As a result, while the main spacer 32 is brought into contact with the lower surface of an alignment layer 28 of the counter substrate 22, the upper surface of the backup spacer 32 is somewhat separated from the lower surface of the alignment layer 28 of the counter substrate 22. Thereby the opening ratio and the precision of the gap are improved owing to respective advantages of the respective spacers 31, 32. Also the fine adjustment of the positioning of both substrates 21, 22 are smoothly carried out.

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 in which a plurality of types of spacers are combined to secure a liquid crystal sealing gap with high accuracy, and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view showing a part of an example of a conventional active matrix type liquid crystal display device. This liquid crystal display device includes an active substrate 1 and a counter substrate 2 made of glass, resin, or the like. A pixel electrode 3 made of ITO and a thin film transistor 4 as a switching element are provided in a matrix on the upper surface of the active substrate 1 (hereinafter, simply referred to as upper and lower positions in the figure). A membrane 5 is provided.

The lower surface of the counter substrate 2 is provided with red, green and blue color filter elements 6, and the lower surface thereof is provided with a counter electrode 7 made of ITO and an alignment film 8. The substrates 1 and 2 are bonded together via a substantially rectangular frame-shaped sealing material (not shown), and a liquid crystal 9 is sealed between the alignment films 5 and 8 of the substrates 1 and 2 inside the sealing material.
In this case, a spherical or cylindrical spacer 1 made of silica glass or resin is provided between the alignment films 5 and 8 of the substrates 1 and 2.
0 is interposed. The spacer 10 regulates a gap in a space in which the liquid crystal 9 is sealed.

[0004]

In this liquid crystal display device, a method of interposing a spacer 10 between the substrates 1 and 2 is generally to spray the spacer 10 on the upper surface of the alignment film 5 of the active substrate 1 by spraying. A method of spraying is used. However, since the spacers 10 are merely sprayed by spraying, the spacers 10 are also sprayed on the pixel electrodes 3, and there is a problem that the aperture ratio is reduced.

On the other hand, as another example of a conventional liquid crystal display device, as shown in FIG. 7, a columnar spacer 11 made of resin is formed on the upper surface of an alignment film 5 of an active substrate 1 by photolithography. . In this case, since the spacer 11 is formed by the photolithography method, the spacer 11 can be formed only on the thin film transistor 4 which is a non-pixel region which is not involved in display, so that the aperture ratio can be improved.

However, in the case of the liquid crystal display device shown in FIG. 7, since the spacer 11 is columnar, the spacer 1
The upper surface of the substrate 1 comes into surface contact with the alignment film 8 of the counter substrate 2. As a result, it is difficult to move the opposing substrate 2 smoothly with respect to the active substrate 1 when the two substrates 1 and 2 are aligned and finely adjusted before bonding them together via the sealing material. There is a problem that it is difficult to fine-tune the size. When the spacer 11 is formed, first, a resin is applied to the upper surface of the alignment film 5 of the active substrate 1 by spin coating to form a resin film. However, it is difficult to make the thickness of the resin film uniform. For this reason, the height of the spacer 11 varies, and there is a problem that the gap accuracy is inferior to the spherical or cylindrical spacer 10 shown in FIG.

An object of the present invention is to improve the aperture ratio and the gap accuracy and to smoothly perform fine adjustment of the alignment of the two substrates when the two substrates are bonded to each other. .

[0008]

According to the first aspect of the present invention, two substrates are bonded via a frame-shaped sealing material with a spacer interposed therebetween, and the two substrates inside the sealing material are bonded to each other. In a liquid crystal display device in which liquid crystal is sealed between substrates, the spacer is a backup spacer made of a resin provided at a predetermined position on a surface of one of the two substrates facing the other substrate; A spherical or cylindrical main spacer is provided in the backup spacer and held by the backup spacer in contact with both opposing surfaces of the substrates. According to a second aspect of the present invention, in the first aspect of the present invention, a diameter of the main spacer is larger than a height of the backup spacer. According to a third aspect of the present invention, in the second aspect of the present invention, the main spacer includes a hydrophobic film provided on a surface thereof. According to a fourth aspect of the present invention, in the second or third aspect, the specific gravity of the main spacer is larger than the specific gravity of the backup spacer. The invention according to claim 5 is the invention according to any one of claims 1 to 4,
The backup spacer is provided at a position that does not affect the aperture ratio. The invention according to claim 6 provides the following:
When manufacturing a liquid crystal display device in which two substrates are bonded via a frame-shaped sealing material and a liquid crystal is sealed between the two substrates inside the sealing material, the other of one of the two substrates is used. A material in which spherical or columnar particles are mixed in a resin is applied to the surface facing the substrate to form a resin film, and the resin film is patterned so that a predetermined region remains, thereby forming a liquid crystal. A spacer for regulating the gap of the sealing space is formed in a state where the particles are held in the resin film. According to a seventh aspect of the present invention, in the sixth aspect of the invention, the resin film is formed so that its thickness is smaller than the diameter of the particles. According to an eighth aspect of the present invention, in the invention of the seventh aspect, particles having a specific gravity larger than that of the resin film are used as the particles. And according to the invention described in claim 1,
A spacer, a backup spacer provided on a surface of one of the two substrates facing the other substrate,
Since each of the spacers has a spherical or cylindrical main spacer provided in the backup spacer and abutting on both opposing surfaces of the substrates, each of the advantages of each spacer improves the pressure resistance of the entire spacer. The aperture ratio and the gap accuracy can be improved, and fine adjustment of the alignment of the two substrates when the two substrates are bonded can be smoothly performed. Further, according to the invention described in claim 6, the surface of one substrate facing the other substrate includes:
A spacer that regulates a gap in a liquid crystal enclosing space by applying a material in which spherical or columnar particles are mixed into a resin to form a resin film and patterning the resin film so that a predetermined region remains. Is formed in a state where the particles are held in the resin film, so that a gap regulating member that can secure a predetermined gap with high accuracy can be easily formed.

[0009]

FIG. 1 is a sectional view of a main part of an active matrix type liquid crystal display device according to an embodiment of the present invention. This liquid crystal display device includes an active substrate 21 and a counter substrate 22 made of glass, resin, or the like. The IT on the upper surface of the active substrate 21
A pixel electrode 23 made of O and a thin film transistor 24 as a switching element are provided in a matrix,
An alignment film 25 is provided on the upper surface.

A red, green, and blue color filter element 26 is provided on the lower surface of the counter substrate 22, and an ITO
A counter electrode 27 and an alignment film 28 are provided. The substrates 21 and 22 are bonded together via a substantially rectangular frame-shaped sealing material (not shown), and a liquid crystal 29 is sealed between the alignment films 25 and 28 of the substrates 21 and 22 inside the sealing material. In this case, a spacer 30 is interposed between the alignment films 25 and 28 of the two substrates 21 and 22.

The spacer 30 is made of a columnar or wall-shaped backup spacer 31 made of resin provided on the upper surface of the alignment film 25 of the active substrate 21 and an inorganic material such as silica glass or resin provided in the backup spacer 31. And a main spacer 32 having a spherical or cylindrical shape. Then, the main spacer 32
Of the backup spacer 31 (for example, 4.2 μm).
(For example, 4.0 μm). Therefore, the main spacer 32 is formed on the alignment film 2 of the counter substrate 22.
8 is in contact with the lower surface of the backup spacer 31
Is slightly away from the lower surface of the alignment film 28 of the counter substrate 22. In this case, it is preferable that the height of the backup spacer 31 be set in a range of about 93% to 98% of the diameter of the main spacer 32. The spacer 30 is provided at a position that does not affect the aperture ratio. Specifically, when the backup spacer 31 has a columnar shape, for example, it is provided only on the thin film transistor 24 and the backup spacer 31 has a wall shape. , For example, a thin film transistor 2
4 is provided only on a data line (not shown) connected to the drain electrode (separated to allow the injection of the liquid crystal 29).

Next, a method for manufacturing a part of the liquid crystal display device will be described with reference to FIGS. First,
As shown in FIG.
A pixel electrode 23 and a thin film transistor 24 as a switching element are provided in a matrix, and an alignment film 25 is provided on the upper surface thereof.

Next, as shown in FIG. 3, on the upper surface of the alignment film 25, a material in which a spherical or cylindrical main spacer 32 made of silica glass, glass fiber or the like is mixed in a resin material of a backup spacer is applied. And resin film 4
Form one. In this case, as described above, the thickness of the resin film 41 is 93% to 98% greater than the diameter of the main spacer 32.
%. . Further, the specific gravity of the main spacer 32 is made larger than the specific gravity of the resin film 41 so that the main spacer 32 is settled in the resin film 41 by its own weight. Thereby, the main spacer 32
Is placed on the alignment film 25 and the apex thereof is held in the resin film 41 in a state of protruding from the upper surface of the resin film 41.

Next, the resin film 4 including the main spacer 32
An etching mask film 42 for forming the backup spacer 31 by etching is patterned at a predetermined location on the upper surface of the substrate 1 using a photosensitive photoresist material. Next, when the resin film 41 is etched through the etching mask film 42, the resin film 41 in a region other than under the etching mask film 42 is removed together with the main spacer 32, and as shown in FIG. Then, a columnar or wall-shaped backup spacer 31 made of resin is formed so as to include the main spacer 32 therein in the above-described state. Next, when the etching mask film 42 is removed, the spacer 30 shown in FIG. 1 is formed.

Here, as an example, 4 wt% of a spherical main spacer 32 having a diameter of 4.2 μm is mixed into the material resin of the backup spacer, and the thickness of the resin film 41 is reduced to 4.0 μm.
m, and the planar shape of the backup spacer 31 is 20 ×
When the thickness is 20 μm, about one main spacer 32 can be present in the backup spacer 31.

As described above, since the backup spacer 31 including the main spacer 32 is formed by the photolithography method, the spacer 30 can be formed only on the thin film transistor 4, for example, so that the aperture ratio can be improved. it can. The main spacer 32 is applied to the columnar or wall-shaped backup spacer 31 made of resin by applying a resin mixed with the main spacer 32 by various coating methods and patterning the applied resin film 41. Since the spacer 30 held while being placed on the alignment film 25 is formed, a gap regulating member that can secure a predetermined gap with high accuracy can be easily formed.

A photosensitive photoresist material is used as a backup spacer material, and the main spacer 32 is mixed in the above-described ratio to form a resin film 41 similar to the above.
May be applied and formed. Thereafter, by exposing and developing the resin film 41 through a mask having a mask pattern corresponding to the arrangement pattern of the backup spacers,
Backup spacer 3 formed in desired shape and arrangement
1 provides a feature of the invention in which at least one main spacer 32 is held in the appropriate form described above.

Then, as shown in FIG.
When the substrates 22 are bonded together via a sealant, the main spacer 32 comes into contact with the lower surface of the alignment film 28 of the counter substrate 22 as described above. Slightly separated from.
Therefore, only the main spacer 32 comes into point contact or line contact with the alignment film 8 of the counter substrate 2. As a result, when the two substrates 21 and 22 are aligned and finely adjusted before the two substrates 21 and 22 are bonded via the sealing material, the opposing substrate 22 can be smoothly moved with respect to the active substrate 21. Fine adjustment of positioning can be performed smoothly.

Further, even if the thickness of the resin film 41 becomes non-uniform not only within one substrate but also between different substrates or different lots, and the height of the backup spacer 31 varies, the alignment film 28 The backup spacer 31 not in contact with the main substrate 32 does not serve as a substantial spacer, and the main spacer 32 in contact with the alignment film 28 of the counter substrate 22 serves as a substantial spacer.
Since the diameter of the main spacer 32 basically has very little variation, the gap accuracy can be improved not only within one substrate but also between different substrates or between different lots.

Further, since the backup spacer 31 serves as a reinforcing member when the main spacer 32 is compressed and deformed in a substrate bonding step or the like, the pressure resistance strength of the entire spacer is improved. In this case, the backup spacer 3
Since the height of 1 is set to 93% to 98% of the diameter of the main spacer 32, the degree of compressive deformation of the main spacer 32 can be suppressed to 93% to 98%. With such a degree of compressive deformation, the main spacer 32 can be sufficiently restored to its original diameter, so that the gap between the substrates is maintained with the desired high accuracy.

As in the other embodiment of the present invention shown in FIG. 5, the surface of a spherical or cylindrical core 32a made of silica glass or glass fiber is used as a main spacer 32 '. Surface treatment using a hydrophobic material such as a chain compound to provide a hydrophobic film 32b may be used. The thickness of the hydrophobic film 32b has little effect on the function of the main spacer 32 'regulating and holding the gap in the liquid crystal enclosing space.
The core 32a alone is used to secure a desired size and high accuracy.
It is extremely thin. In FIG. 5, for convenience of explanation, the hydrophobic film 32b is schematically illustrated as being thick.

With the above-described structure, the adhesion between the main spacer 32 'and the backup spacer 31 is reduced, the main spacer 32' is rotatable, and the alignment of the substrates 21 and 22 is fine. The adjustment can be performed more smoothly. Also, the main spacer 3
The dispersibility when mixing 2 ′ into the backup spacer 31 is improved.

Further, the present invention is not limited to the active matrix type liquid crystal display device, but can be widely applied to other liquid crystal display devices.
The case where the first and the second 32 are provided on the active substrate 21 side has been described.
1. The main spacer 32 may be provided on any side of the pair of substrates.

[0024]

As described above, according to the first aspect of the present invention, the spacer is provided at a predetermined position on the surface of one of the two substrates facing the other substrate. And a spherical or cylindrical main spacer held by the backup spacer in contact with both opposing surfaces of the two substrates. The pressure resistance of the entire spacer can be improved, the aperture ratio and the gap accuracy can be improved, and fine adjustment of the alignment of the two substrates when the two substrates are bonded can be smoothly performed. According to the invention as set forth in claim 6, a resin film is formed by applying a material in which spherical or columnar particles are mixed in a resin to a surface of one substrate facing the other substrate, By patterning the resin film so that a predetermined region remains, a spacer that regulates the gap in the backup liquid crystal enclosing space is formed in a state where the particles are held in the resin film. It is possible to easily form a spacer that can secure a predetermined gap with high accuracy without lowering the aperture ratio.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a part of the liquid crystal display device shown in FIG.
Sectional view of what was initially prepared.

FIG. 3 is a cross-sectional view of the manufacturing process following FIG. 2;

FIG. 4 is a sectional view of the manufacturing process following FIG. 3;

FIG. 5 is a sectional view of a main part of a liquid crystal display device according to another embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of an example of a conventional liquid crystal display device.

FIG. 7 is a partial cross-sectional view of another example of a conventional liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Active substrate 22 Counter substrate 23 Pixel electrode 24 Thin film transistor 29 Liquid crystal 30 Spacer 31 Backup spacer 32, 32 'Main spacer

Claims (8)

[Claims] 1. A liquid crystal display device wherein two substrates are bonded together via a frame-shaped sealing material with a spacer interposed therebetween, and a liquid crystal is sealed between the two substrates inside the sealing material. The spacer is a backup spacer made of a resin provided at a predetermined position on a surface of one of the two substrates facing the other substrate,
A liquid crystal display device comprising: a spherical or cylindrical main spacer held by the backup spacer in a state of contacting both opposing surfaces of the two substrates. 2. The liquid crystal display device according to claim 1, wherein a diameter of the main spacer is larger than a height of the backup spacer. 3. The liquid crystal display device according to claim 2, wherein the main spacer is provided with a hydrophobic film on a surface thereof. 4. The liquid crystal display according to claim 2, wherein the specific gravity of the main spacer is larger than the specific gravity of the backup spacer. 5. The liquid crystal display device according to claim 1, wherein the backup spacer is provided at a position that does not affect the aperture ratio. 6. A manufacturing method of a liquid crystal display device in which two substrates are bonded together via a frame-shaped sealing material and a liquid crystal is sealed between the two substrates inside the sealing material. On a surface of one of the substrates facing the other substrate, a material in which spherical or columnar particles are mixed in a resin is applied to form a resin film, and the resin film is formed so that a predetermined region remains. A method for manufacturing a liquid crystal display device, comprising forming, by patterning, a spacer that regulates a gap in a liquid crystal sealed space in a state where the particles are held in a resin film. 7. The method according to claim 6, wherein the resin film is formed so that its thickness is smaller than the diameter of the particles. 8. The method according to claim 7, wherein a specific gravity of the particles is larger than a specific gravity of the resin film.