JP2000352720A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent distortion of an image in the peripheral edge of an image display region due to increase in the gap between transparent substrates inside a sealing part. SOLUTION: The device consists of a first transparent substrate 1a and a second transparent substrate 1b each having a film forming part 2a, 2b including electrode layers which regulate the image display region on the principal planes facing each other, a liquid crystal layer 11 between the first and second transparent substrates 1a, 1b and having a spherical first spacer 10 within, and a sealing material joining the first transparent substrate 1a and the second transparent substrate 1b to seal the liquid crystal layer 11 inside. The sealing material consists of a main sealing part 4 around the image display region and containing a second spacer which is thicker than the first spacer 10, an outer sealing part 6 around the main sealing part 4 and containing a third spacer 7 which has almost same thickness as the second spacer 5, and an intermediate sealing part 8 between the main sealing part 4 and the outer sealing part 6 and containing a fourth spacer 9 which is thicker than the second spacer 5.

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 peripheral portions of two transparent substrates are joined using a sealing material and a spacer.

[0002]

2. Description of the Related Art Conventional liquid crystal display devices (Liquid Crystal D)
FIG. 5 is a plan view of a liquid crystal panel of isplay (LCD).
The figure relates to a sealing portion (hereinafter referred to as a sealing portion) of the liquid crystal panel 20 and a spacer, wherein 4 is a main sealing portion provided along the periphery of an image display area of the liquid crystal panel 20, and 6 is a main sealing portion. An outer seal portion 10 provided outside of 4 has a diameter corresponding to a liquid crystal layer having a predetermined thickness, and is a transparent fibrous or transparent spherical first spacer made of glass fiber, silica sphere, or the like. . The first spacers 10 are scattered at a desired number density in order to make the thickness of the liquid crystal layer uniform so that the thickness does not change due to external force.

FIG. 2 is a cross-sectional view taken along the line BB of FIG. 4, wherein 1a is a first transparent substrate made of glass or the like, 1b is a second transparent substrate made of glass or the like,
Reference numeral 2a denotes a film forming unit including an electrode layer for a scanning line and a signal line made of ITO or the like for defining an image display area. In addition, a color filter, an overcoat of a color filter, an alignment film, and the like are laminated. The liquid crystal layer 11 of the second transparent substrate 1b
A similar film-forming portion 2b is also formed on the main surface on the side. FIG. 3 shows a detailed configuration of the film forming units 2a and 2b. In the same figure, 22 is a color filter, 23 is an overcoat of the color filter, 24a is an electrode layer for a scanning line formed on the first transparent substrate 21a side, and 24b is formed on the second transparent substrate 21b side. An electrode layer for signal lines, 25a is an alignment film formed on the electrode layer 24a, 25b is an electrode layer 24b
It is an alignment film formed thereon. The overcoat 23 is formed on the first transparent substrate 21 by spin coating or the like.
The other layer is formed on the entire surface of a, and is provided in a region corresponding to the image display region.

Reference numeral 26 denotes a first spacer, 27 denotes a main seal portion, 28 denotes a second spacer, 29 denotes an outer seal portion, 3
0 is a third spacer, and 31 is a liquid crystal layer made of a nematic liquid crystal or the like.

In FIG. 2, reference numeral 5 denotes a second spacer provided in the main seal portion 4, reference numeral 7 denotes a third spacer provided in the outer seal portion 6, and reference numeral 11 denotes a liquid crystal layer made of nematic liquid crystal or the like. is there. The second spacer 5 and the third spacer 7 have substantially the same thickness because the thickness of the main seal portion 4 and the thickness of the outer seal portion 6 are substantially the same.

In the case of such a simple matrix type color LCD, a plurality of scanning lines are formed on the first transparent substrate 1.
a, a plurality of signal lines are formed on the second transparent substrate 1b, and the first transparent substrate 1a and the second transparent substrate 1b are arranged in a state where the scanning lines and the signal lines face each other and are orthogonal to each other. It is a joined structure. In addition, TFT (Thin Film Transist
or: an active matrix type LCD in which each pixel is formed as a driving electrode using a TF.
T is included in the film forming unit 2a or 2b, and the surface electrode facing the TFT is included in the other film forming unit.

[0007]

However, in the above-mentioned conventional LCD, the area on the inner side (center side of the liquid crystal panel) separated from the main seal portion 4 by about 5 to 10 mm or more is the thickness of the dispersed first spacers 10. As a result, a uniform spacing can be obtained and a good display quality without distortion can be obtained. However, the following problem occurs in the region S1 (FIG. 2) 5 to 10 mm inside the main seal portion 4. Had occurred.

A first transparent substrate 1a and a second transparent substrate 1b
Are bonded by the main seal portion 4 and the outer seal portion 6, the outer main surfaces of the first transparent substrate 1a and the second transparent substrate 1b are pressed and pressed. Since the first spacer 10 existing between the first and second spacers 6 and 7 has a smaller thickness than the second and third spacers 5 and 7, the first seal 10 and the outer seal 6 are pressed by the pressing force (arrows in FIG. 2). The distance between the first transparent substrate 1a and the second transparent substrate 1b is reduced between them, and due to the reaction, the distance widens in the area S1 (open arrow in FIG. 2), and is adhered and fixed in this state. As a result, there is a problem that the image in the region S1 is distorted.

Therefore, the present invention has been completed in view of the above circumstances, and an object of the present invention is to eliminate distortion of an image due to a wide gap between transparent substrates at a peripheral portion of an image display area.

[0010]

According to the present invention, there is provided a liquid crystal display device comprising a first transparent substrate and a second transparent substrate each having a film-forming portion including an electrode layer defining an image display area formed on opposing main surfaces. A substrate, disposed between the first and second transparent substrates, a liquid crystal layer in which a spherical or fibrous first spacer is provided, and the first transparent substrate and the second transparent substrate And a sealing material for sealing the liquid crystal layer inside, the sealing material is a main sealing portion around an image display area containing a second spacer thicker than the first spacer, An outer sealing portion around a main sealing portion containing a third spacer having substantially the same thickness as the second spacer, and provided between the main sealing portion and the outer sealing portion; and And an intermediate sealing portion containing a fourth spacer thicker than the second spacer.

[0011] According to the present invention, with the above structure, the pressing force at the time of pressing the first transparent substrate and the second transparent substrate against each other can be obtained.
The gap between the transparent substrates narrows between the main sealing portion and the outer sealing portion, and the reaction causes the inside of the main sealing portion (toward the center of the liquid crystal panel).
Has an effect of preventing the image from being distorted at the periphery of the image display area.

In the present invention, preferably, the thickness of the fourth spacer is 0.5 to 0.5 times larger than that of the second spacer.
It is characterized by being 2.0 μm larger.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The LCD of the present invention will be described below. 1 and 4 show an LCD according to the present invention.
The same parts as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 4, an intermediate seal portion 8 is provided between the main seal portion 4 and the outer seal portion 6. In FIG. 2, the intermediate seal portion 8 is provided on a part of the periphery of the main seal portion 4, but may be provided over the entire periphery of the main seal portion 4. Further, the intermediate seal portion 8 does not need to be continuous, and may be formed intermittently. In FIG. 1, the number of intermediate seal portions 8 is one between the main seal portion 4 and the outer seal portion 6, but may be two or more.

FIG. 1 is a cross-sectional view taken along the line AA of FIG. 4. As shown in FIG. 1, film forming sections 2a and 2b each including an electrode layer defining an image display area on opposing main surfaces. Transparent substrate 1a and second transparent substrate 1b each formed with
Disposed between the first and second transparent substrates 1a and 1b,
The liquid crystal layer 11 in which the spherical or fibrous first spacer 10 is provided is joined to the first transparent substrate 1a and the second transparent substrate 1b, and the liquid crystal layer 11 is sealed inside. A sealing material (sealing material), wherein the sealing material is a main sealing portion 4 around an image display area containing a second spacer 5 thicker than the first spacer 10; An outer seal portion 6 around the main seal portion 4 containing a third spacer 7 having substantially the same thickness, and provided between the main seal portion 4 and the outer seal portion 6; And the intermediate seal portion 8 containing the thick fourth spacer 9.

The intermediate seal portion 8 includes a fourth spacer 9 which is thicker than the second spacer 5, and preferably has a thickness of the fourth spacer 9 smaller than that of the second spacer 5. 0.5 to 2.0 μm. When the thickness is less than 0.5 μm, the contact portion of the fourth spacer 9 is buried in the overcoat included in the film-forming portion 2a during pressure bonding, and the fourth spacer 9 is thicker than the second spacer 5 according to the present invention. The effect cannot be obtained. That is, the effect of preventing the space between the first transparent substrate 1a and the second transparent substrate 1b from being widened at the periphery of the image display area at the time of pressure bonding cannot be obtained.
If the thickness exceeds 2.0 μm, the distance between the first transparent substrate 1a and the second transparent substrate 1b in the intermediate seal portion 8 becomes too large. The effect of the present invention of preventing the distance between the first transparent substrate 1a and the second transparent substrate 1b from increasing is not obtained.

These first to fourth spacers 10, 5,
Reference numerals 7 and 9 denote fibrous, spiral (coiled) materials such as glass fiber and plastic fiber, spherical ones such as silica spheres and plastic spheres, and other light-transmitting materials such as fibrous and helical (coiled) materials. ) Or a sphere and can be used if it has a certain degree of rigidity. The main seal portion 4, the outer seal portion 6, and the intermediate seal portion 8 are made of an adhesive resin such as an ultraviolet curable resin such as an epoxy resin or an acrylic resin, or a thermosetting resin, and are provided around the image display area. It may be colored black, gray, brown, etc. for the purpose of absorbing and blocking excess light. In that case, the second, third, and fourth spacers 5, 7, and 9 may also be colored black, gray, brown, or the like.

Further, second, third, and fourth spacers 5,
The main seal portion 4, the outer seal portion 6, and the intermediate seal portion 8 are made porous by impregnating the resin component of the seal portion material with the resin component and making it easy to be fixed in the seal portion.
The liquid crystal layer 11 may be configured so as not to protrude or be separated from other portions such as the liquid crystal layer 11. Alternatively, by forming fine projections on the surfaces of the second, third, and fourth spacers 5, 7, 9 and roughening the surface, the surface area in contact with the resin component of the seal portion material is increased, and the inside of the seal portion is increased. , And even if the diameters of the second, third, and fourth spacers 5, 7, 9 have a distribution (grain size distribution), the projections are easily deformed by being crushed or dented at the time of crimping, It is easy to make the gap between the transparent substrates uniform.

The center of the intermediate seal portion 8 is provided at a substantially intermediate position between the main seal portion 4 and the outer seal portion 6.
If the distance between the main seal portion 4 and the outer seal portion 6 is L (FIG. 1) and the distance between the main seal portion 4 and the outer seal portion 6 is within a range of about ± 0.1 L, the present invention is not limited to this. The effect is obtained. In order to prevent the gap between the transparent substrates from being widened with the intermediate seal portion 8 as a fulcrum at the time of pressure bonding in a region of about 5 to 10 mm inside the main seal portion 4, the intermediate seal portion 8 is located closer to the outer seal portion 6 than the intermediate point. It is preferable to provide the center of the seal portion 8.

The third spacer 7 has substantially the same thickness as the second spacer 5, but may have a thickness between the second spacer 5 and the fourth spacer 9; The one transparent substrate 1a and the second transparent substrate 1b are likely to be deformed on the center side of the liquid crystal panel at the time of pressure bonding, and the gap between the transparent substrates inside the main seal portion 4 is more difficult to expand.

In the above embodiment, the color LCD in which the film forming section 2a has a color filter and an overcoat
However, the present invention is also applicable to a monochrome LCD having no color filter and no overcoat. In that case, the film forming unit 2a is composed of an electrode layer and an alignment film, and the same applies to the film forming unit 2b.

The present invention also relates to an STN (Super Twisted Ne
matic) type LCD, TN (TwistedNematic) type LC
D, ferroelectric liquid crystal LCD, antiferroelectric liquid crystal LCD,
Simple matrix type LCD such as bistable liquid crystal type LCD,
The present invention can be applied to various LCDs such as an active matrix type LCD using a TFT.

Thus, the present invention has the effect of preventing the gap between the transparent substrates inside the main seal portion 4 from being widened, thereby preventing the image from being distorted at the periphery of the image display area.

It should be noted that the present invention is not limited to the above embodiment, and various changes may be made without departing from the scope of the present invention.

[0024]

Embodiments of the present invention will be described below.

(Embodiment) A simple matrix type color LCD shown in FIGS. 1 and 4 was constructed as follows. An RGB color filter, an overcoat made of a transparent resin, a transparent electrode layer made of ITO for a plurality of scanning lines, and an alignment for aligning liquid crystal molecules made of polyimide are formed on one main surface of a first transparent substrate 1a made of glass. Films are sequentially laminated to form a film forming unit 2a
Was formed, and a plurality of transparent electrode layers for signal lines made of ITO and an alignment film made of polyimide were sequentially laminated on one main surface of the second transparent substrate 1b to form a film forming section 2b. At this time, in the film forming section 2a, the thickness of the color filter is about 1.1 μm, the thickness of the overcoat is about 2.2 μm, the thickness of the electrode layer is 0.33 μm, and the thickness of the alignment film is 0.07 μm.
m. In the film forming section 2b, the thickness of the electrode layer was 0.2 μm, and the thickness of the alignment film was 0.07 μm.

And, as the first spacer 10, a spherical member made of divinylbenzene and having a diameter of 6.63 μm,
Glass fiber with a sectional diameter of 7.5 μm as the second spacer 5, glass fiber with a sectional diameter of 7.5 μm as the third spacer 7, and glass fiber with a sectional diameter of 8.5 μm as the fourth spacer 9 Using
In a state where the film forming unit 2a and the film forming unit 2b are opposed to each other and the signal line and the scanning line are orthogonal to each other, the first transparent substrate is formed by the main seal unit 4, the intermediate seal unit 8, and the outer seal unit 6 each made of epoxy resin. 1a and the second transparent substrate 1b were pressed and joined.

On the other hand, as a comparative example, the one having the structure shown in FIG.

The average thickness of the liquid crystal layer 11, that is, the average distance between the film-forming portion 2a and the film-forming portion 2b, was measured to be about 6.4 μm in these manufactured LCDs.
The average interval in FIG. 2 is approximately 6.4 to 6.4 in this embodiment.
It was 6.5 μm, but about 6.6 to 6.7 μm in the comparative example.
m, which was larger by 0.3 μm than the present example. Due to the spread, in the comparative example, the distortion of the image was visually confirmed at the peripheral portion of the image display area having a width of about 10 mm. However, in the present embodiment, it was completely eliminated and the display quality was good.

[0029]

According to the present invention, there is provided a seal material in which a main seal portion around an image display area containing a second spacer thicker than a first spacer and a third spacer having substantially the same thickness as the second spacer. And an outer seal portion around the main seal portion, and an intermediate seal portion provided between the main seal portion and the outer seal portion and including a fourth spacer thicker than the second spacer. By having, by pressing force when pressing the first transparent substrate and the second transparent substrate,
The gap between the transparent substrates is narrowed between the main seal portion and the outer seal portion, and the reaction causes the gap between the transparent substrates inside the main seal portion to widen, thereby preventing the image from being distorted at the periphery of the image display area. Has an effect.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of the vicinity of a seal portion of an LCD according to the present invention.

FIG. 2 is a partial cross-sectional view showing the vicinity of a seal portion of a conventional LCD.

FIG. 3 is a partial cross-sectional view showing the details of the configuration of a film forming unit in a conventional LCD, showing the vicinity of a seal unit.

FIG. 4 is a plan view of the liquid crystal panel of the present invention.

FIG. 5 is a plan view of a conventional liquid crystal panel.

[Explanation of symbols]

 1a: first transparent substrate 1b: second transparent substrate 2: film forming section 4: main seal section 5: second spacer 6: outer seal section 7: third spacer 8: intermediate seal section 9: fourth Spacer 10: First spacer

Claims (2)

[Claims] 1. A first transparent substrate and a second transparent substrate each having a film forming portion including an electrode layer defining an image display area on opposing main surfaces, and the first and second transparent substrates. A liquid crystal layer disposed between the liquid crystal layer and a spherical or fibrous first spacer provided therein, and the first transparent substrate and the second transparent substrate are joined to each other, and the liquid crystal layer is sealed inside. A sealing material, wherein the sealing material is a main sealing portion around an image display area containing a second spacer thicker than the first spacer, and a second sealing material having substantially the same thickness as the second spacer. An outer sealing portion around a main sealing portion containing three spacers, and a fourth spacer provided between the main sealing portion and the outer sealing portion, and being thicker than the second spacer. A liquid crystal display device comprising: 2. The liquid crystal display device according to claim 1, wherein the thickness of the fourth spacer is larger than that of the second spacer by 0.5 to 2.0 μm.