JP2001264775A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid display failure due to fluctuation of the gap between substrates facing each other. SOLUTION: The device has a pair of transparent substrates disposed facing each other, an inner frame sealing agent to hold and stop a liquid crystal which fills the region corresponding to the display part, and an outer frame sealing agent in the outside of the inner frame sealing agent so as to fix one transparent substrate to the other transparent substrate, both the sealing agents applied between the transparent substrates. At least one of the inner frame sealing agent and the outer frame sealing agent contains a spacer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device formed by a so-called dropping method.

[0002]

2. Description of the Related Art In a so-called dropping encapsulation method, a frame-shaped resin layer is formed on a liquid crystal side surface of one of transparent substrates disposed opposite to each other via a liquid crystal so as to surround a liquid crystal display area. After forming columnar spacers in the liquid crystal display area, liquid crystal is dropped into the frame of the resin layer, and the other transparent substrate is joined by an adhesive layer formed around the transparent substrate.

[0003] In this method, each transparent substrate is previously arranged to face each other via a sealant formed so as to surround the liquid crystal display area, and liquid crystal is sealed through a liquid crystal fill opening formed in a part of the sealant. Since the operation is extremely simple as compared with the above, mass production of the liquid crystal display device can be realized.

[0004]

However, in the liquid crystal display device configured as described above, the gap fluctuates due to the narrowing of the gap between the opposing substrates due to the tendency to increase the size and the response speed. It was pointed out that uniformity could not be achieved.

[0005] When the gap between the opposing substrates fluctuates in this way, the display on the display unit becomes uneven, which causes display defects.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a liquid crystal display device in which a display failure due to a change in a gap of a counter substrate is avoided.

[0007]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, the liquid crystal display device according to the present invention comprises:
Basically, a pair of transparent substrates opposed to each other, an inner frame sealing agent between the transparent substrates for blocking liquid crystal filled in a region corresponding to a display portion, and one outside the inner frame sealing agent. And an outer frame sealing agent for fixing the other transparent substrate to the transparent substrate, wherein at least one of the inner frame sealing agent and the outer frame sealing agent contains a spacer. It is.

In the liquid crystal display device having such a configuration, the gap between the transparent substrates can be made uniform by the spacer contained in either the inner frame sealing agent or the outer frame sealing agent. Become.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the liquid crystal display device according to the present invention will be described below with reference to the drawings.

Embodiment 1 << Structure >> FIG. 1A is a view showing the appearance of a liquid crystal display device according to the present invention, and FIG. 1B is a sectional view taken along the line bb. In each drawing, there is a pair of transparent substrates SUB1 and SUB2 which are arranged to face each other. Although not shown, a metal layer, a semiconductor layer, an insulating layer, and the like are laminated in a predetermined pattern on each of the opposing surfaces of the transparent substrates SUB1 and SUB2 to form an electronic circuit.

This electronic circuit is composed of a pair of electrodes for each pixel arranged in a matrix on a display part AR in a central part excluding the periphery of each transparent substrate, and a signal line for supplying a signal to these electrodes. The light transmittance of the liquid crystal LC interposed between the transparent substrates SUB1 and SUB2 is controlled by the electric field generated between the electrodes.

A display part AR composed of a set of pixels has a columnar spacer SP formed on one transparent substrate SUB1 side.
1 are scatteredly formed at the same height, and the transparent substrate SU
The gap between B1 and the other transparent substrate SUB2 disposed opposite to each other is determined by the columnar spacer SP1.

The liquid crystal LC is provided on each transparent substrate SU.
An inner frame sealant ISL formed between B1 and SUB2 so as to surround the display unit AR is used for damming, and is filled in a region corresponding to the display unit AR.

The inner frame sealant ISL is made of a resin layer that is cured by both heat and ultraviolet rays, and contains, for example, a spherical spacer SP2 therein.

The reason why the resin layer of the heat and ultraviolet curing type is used as the material of the inner frame sealant ISL is that, unlike the foamable resin or the porous resin, it is possible to avoid the generation of bubbles in the liquid crystal. .

The reason why the spherical spacer SP2 is mixed with the inner frame sealing agent ISL is that the above-mentioned columnar spacer S
This is because, together with P1, a gap between the transparent substrates SUB1 and SUB2 is to be secured uniformly.

An outer frame sealant OSL is formed between the transparent substrates SUB1 and SUB2 so as to surround the inner frame sealant ISL, and the other transparent substrate SUB1 is fixed to one transparent substrate SUB2. .

The outer frame sealant OSL is made of, for example, a resin layer which is cured by both heat and ultraviolet rays, and has, for example, a spherical spacer (not shown) mixed therein.

The reason why the spherical spacer is mixed into the outer frame sealant OSL is that the gap between the transparent substrates SUB1 and SUB2 is made uniform with the columnar spacer SP1 and the spacer SP2 in the inner frame sealant ISL. This is to secure them.

In this case, as the material of the outer frame sealant OSL, for example, a foamable resin or a porous resin may be used without using a resin layer of a curable type combined with heat and ultraviolet rays. This is because the outer frame sealant OSL does not directly contact the liquid crystal SL, and there is no inconvenience that bubbles are generated in the liquid crystal SL.

<< Manufacturing Method >> FIG. 2 is a process chart showing one embodiment of a manufacturing method of the above-mentioned liquid crystal display device. Step 1. (FIG. 7A) A transparent substrate SUB1 corresponding to the lower substrate is prepared. This transparent substrate has a state in which a metal layer, a semiconductor layer, an insulating layer, and the like are each laminated in a predetermined pattern on the liquid crystal side surface, and signal lines, switching elements, electrodes of each pixel, and the like are formed. Has become.

On the liquid crystal side surface of the transparent substrate SUB1,
After a resin film is formed by uniformly applying a resin solution of a combination of heat and ultraviolet rays with a thickness of, for example, 4 μm, the resin film is selectively exposed to ultraviolet light, and the resin film is further developed. The columnar spacers SP1 scattered in the display section are formed.

This columnar spacer SP1 can be formed at a predetermined position in the display part AR, and furthermore, by forming a resin film having a uniform thickness, it is possible to obtain a spacer having a uniform height. .

Then, the inner frame sealant ISL is formed so as to surround the display part AR which is an aggregate of pixels arranged in a matrix.

The inner frame sealing agent ISL has a function of a weir body for preventing the liquid crystal to be filled in the display part AR from flowing out.

That is, on the liquid crystal side surface of the transparent substrate SUB1, a mixture of a heat and ultraviolet curable resin solution and, for example, a spherical spacer SP2 is applied by a so-called spinner coating.

Here, the spherical spacer SP2, together with the columnar spacer SP1 described above, is provided on the transparent substrate SUB1.
This is to secure a constant gap with another transparent substrate SUB2 facing the substrate. It is preferable that a resin liquid of a curable type combined with heat and ultraviolet rays is selected so as to have low contamination to the liquid crystal.

The thickness of the resulting resin film is controlled by the number of rotations of the spinner, the spin time, the viscosity of the resin solution, and the like, and is formed to a thickness of, for example, 5 microns.

Next, this resin film is selectively exposed to ultraviolet light,
Further, by developing the resin film, an inner frame sealing agent ISL containing the spacer SP2 is formed so as to surround the liquid crystal display region.

Thereafter, the inner frame sealing agent ISL is irradiated with ultraviolet light (i-line), and the inner frame sealing agent ISL is irradiated with the columnar spacer SP2 by about 80%.
After annealing at a temperature of about 5 minutes for about 5 minutes.
Full curing at a temperature of ° C.

Further, as shown in FIG. 3, which is an enlarged view of the dotted circle A in FIG. 2A, the alignment film OR is formed on the surface of the transparent substrate SUB1 on which the inner frame sealant ISL is formed on the liquid crystal LC side.
The material of I1 is formed by coating, leveling, and firing. In this case, the material is formed not only on the display area AR but also on at least the inner side wall of the inner frame sealant ISL, and rubbing is performed.

As a result, a rubbing process is also performed on the inner side wall of the inner frame sealant ISL, and the liquid crystal L
Since the liquid crystal is oriented in a direction perpendicular to the orientation direction of C, light leakage from the inner frame sealant ISL can be prevented.

Step 2. The liquid crystal LC is dropped into the display part AR surrounded by the inner frame sealant ISL. It is preferable that the liquid crystal LC is dropped in a slightly larger amount than the space surrounded by the inner frame sealing agent ISL by utilizing the surface tension.

This is because the space of the display part AR formed with the other transparent substrate SUB2 disposed opposite to the space is not filled with the liquid crystal mixed with air.

Step 3. Transparent substrate SUB equivalent to upper substrate
Prepare 2 The transparent substrate SUB2 is in a state in which a metal layer, an insulating layer, and the like are laminated in a predetermined pattern on the liquid crystal side surface, and a black matrix layer, a filter layer, and the like are formed.

Then, an outer frame sealant OSL is formed so as to surround the display section AR, which is an aggregate of pixels arranged in a matrix.

The outer frame sealant OSL is formed outside the inner frame sealant ISL of another transparent substrate SUB1 disposed to face the outer frame sealant OSL.

The outer frame sealant OSL is formed by applying an ultraviolet curable adhesive mixed with, for example, a spherical spacer (not shown) of about 5 μm using a dispenser.

Here, the spherical spacer, together with the columnar spacer SP1 and the spherical spacer SP2 mixed in the inner frame sealing agent ISL, can accurately and precisely maintain the gap between the transparent substrate SUB2 and another transparent substrate SUB1 facing the same. It is for securing. Each transparent substrate SU is formed by the spherical spacer SP2 mixed in the inner frame sealant ISL.
When the gap between B1 and SUB2 can be ensured with high accuracy, it is not necessary to mix a spherical spacer into the outer frame sealant OSL.

Then, the thus formed transparent substrate S
UB2 is bonded to the transparent substrate SUB1 by bonding with the sealant in a state where the surfaces of the transparent substrate SUB1 and the liquid crystal side face each other.

Step 4. When the gap between one transparent substrate SUB1 and the other transparent substrate SUB2 reaches a predetermined value, the outer sealing agent OSL is irradiated with ultraviolet rays to fix the transparent substrates SUB1 and SUB2. Plan.

<< Another manufacturing method >> In the above-described method for manufacturing a liquid crystal display device, the inner frame sealing agent ISL is formed on one transparent substrate side, and the outer frame sealing agent OSL is formed on the other transparent substrate side. .

However, these sealants ISL, OSL
May be formed on one of the transparent substrates SUB1 and SUB2.

The inner frame sealant ISL is formed by selectively exposing (photolithography) a resin film formed on the entire surface of a transparent substrate. Other methods include screen printing, film printing, and offset printing. printing,
Needless to say, it may be formed using a dispenser or an ink jet.

Further, the outer frame sealant OSL is formed by a dispenser. Alternatively, the outer frame sealant OSL may be formed by photolithography, screen printing, film printing, offset printing, or inkjet. It goes without saying that this may be done.

Example 2 As the inner frame sealant ISL shown in Example 1, a bisphenol A epoxy resin having a fluorine-based long-chain alkyl group was used.

By using this material, it was confirmed that the direction of the liquid crystal around the inner frame sealant became uniform and vertical, and that when the display was black, light leakage in this portion could be prevented.

[Embodiment 3] The inner frame sealing agent ISL shown in the above-mentioned Embodiment 1 was black, and this sealing agent ISL was used.
It has been confirmed that by using a black spacer SP2 as well, uneven display around the inner frame sealant ISL can be avoided.

This is presumably because ultraviolet rays irradiated during curing of the inner frame sealant ISL damage liquid crystal molecules or polymers of the alignment film, and the inner frame sealant ISL and the spacer SP2 must be blackened. Thus, it is considered that the transmittance of the ultraviolet rays is reduced, and the influence thereof is reduced.

Further, with this configuration, it is possible to prevent the backlight from leaking from the inner frame sealing agent ISL, and to improve the heat absorption efficiency of ultraviolet light to shorten the curing speed of the material. Has an effect.

Therefore, such a configuration can be applied not only to the inner frame sealant ISL but also to the outer frame sealant OSL.

In the above-described embodiment, the spacer contained in the sealant is spherical, but it is needless to say that the present invention is not limited to this shape.

It is needless to say that the spacer may be a columnar spacer fixed to one substrate.

In this case, the formation of the columnar spacers SP1 formed in the display section at the same time as that of the columnar spacers SP1 makes it possible to avoid complicated manufacturing.

[0056]

As is apparent from the above description,
ADVANTAGE OF THE INVENTION According to the liquid crystal display device by this invention, the display defect by the fluctuation | variation of the gap of a counter substrate can be avoided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a process chart showing one embodiment of a method for manufacturing a liquid crystal display device according to the present invention.

FIG. 3 is an enlarged view of a configuration in a dotted circle frame of FIG.

[Description of Signs] SUB1, SUB2: Transparent substrate, AR: Display unit, I
SL: inner frame sealing agent, OSL: outer frame sealing agent, SP
1, SP2 ... spacer, ORI1 ... alignment film.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 20, 2000 (200.4.2
0)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Shigeru Matsuyama 3300 Hayano, Mobara-shi, Chiba F-term in Display Group, Hitachi, Ltd. (reference) 2H089 LA07 LA09 LA15 LA19 LA20 LA42 MA04Y NA22 NA39 NA44 NA45 PA02 PA06 PA16 QA12 QA14 5C094 AA03 AA55 BA43 CA19 EC02 FB01 FB20

Claims (5)

[Claims] 1. A pair of transparent substrates opposed to each other, an inner frame sealing agent between the transparent substrates for blocking liquid crystal filled in a region corresponding to a display section, and one outside the inner frame sealing agent. A liquid crystal, comprising: an outer frame sealing agent for fixing the other transparent substrate to the transparent substrate, wherein at least one of the inner frame sealing agent and the outer frame sealing agent contains a spacer. Display device. 2. A pair of transparent substrates disposed opposite to each other, an inner frame sealing agent between the transparent substrates for blocking liquid crystal filled in a region corresponding to a display portion, and one outside the inner frame sealing agent. An outer frame sealing agent for fixing the other transparent substrate to the transparent substrate, wherein at least one of the inner frame sealing agent and the outer frame sealing agent contains a spacer, and the inner frame sealing agent And at least the inner frame sealant of the outer frame sealant,
A liquid crystal display device formed of a resin that can be cured by both heat and ultraviolet light. 3. The rubbing treatment according to claim 1, wherein an alignment film formed on the display section is formed to extend on a side wall of the inner frame sealing agent, and a rubbing process is performed. 3. The liquid crystal display device according to 1. 4. A pair of transparent substrates opposed to each other, an inner frame sealing agent between the transparent substrates for blocking liquid crystal filled in a region corresponding to a display portion, and one outside the inner frame sealing agent. An outer frame sealing agent for fixing the other transparent substrate to the transparent substrate, wherein at least the inner frame sealing agent of the inner frame sealing agent and the outer frame sealing agent contains a spacer; A liquid crystal display device characterized in that the frame sealant and the spacer are colored black. 5. The liquid crystal display device according to claim 1, wherein the outer frame sealing agent is formed so as to surround the inner frame sealing agent.