JPH0820627B2 - Liquid crystal display element manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a liquid crystal display device.

2. Description of the Related Art In general, a liquid crystal display device has two glass substrates 2, 2'having patterned transparent electrodes 1, 1'on their respective surfaces facing each other as shown in FIG. The liquid crystal 3 is interposed between the two and the periphery is fixed with a sealant 4, and polarizing plates 5 and 5'are provided on both surfaces thereof, and in the case of a reflection type, a reflection layer 6 such as aluminum is further formed on one outside. Then configured.

Here, as a method of interposing the liquid crystal 3 between the two glass substrates 2 and 2 ', generally, as shown in the perspective view of FIG. The other glass substrate 2 ', which is opposite to the glass substrate 2', is attached with the sealant 4 provided therein, the liquid crystal 3 is injected from the liquid crystal injection port 4 ', then the liquid crystal 3 is sealed with an adhesive or the like, and cut into pieces of a desired size. The method of division is used (hereinafter referred to as the injection method).

Also, a method has been proposed in which after forming a sealant having no injection port, a necessary amount of liquid crystal 3 is dropped in the central part and the opposite glass substrate 2'is attached and fixed. There are many difficulties, and this method has not been put to practical use (hereinafter referred to as the dropping method).

Problems to be Solved by the Invention Since the injection method generally injects by depressurizing and pressurizing in a state where the injection port is in contact with the liquid crystal in the liquid crystal reservoir, expensive liquid crystal is wasted several times as much as the required injection amount. When the overall size and shape increase, it takes an extremely long time to inject into a large area with a thin interval of several μm, and there are many difficulties in terms of production efficiency. Further, when the filling port is sealed, the sealing adhesive force becomes insufficient unless the attached liquid crystal is sufficiently wiped, and bubbles tend to be generated if the liquid crystal is wiped too much, which requires various fine control in production technology.

As a means for solving these problems, a dropping method has been considered and various proposals have been made. However, according to this method, a sealant layer made of an adhesive or the like is formed in the peripheral portion, and a necessary amount of liquid crystal is put in the layer to perform pressure bonding and curing. In this case, the distance between both substrates is as thin as several μm. For,
For example, even with a size of 200 x 300 mm ² , the required amount of liquid crystal is several hundred mg.
We have to weigh a very small amount. Bubbles tend to remain even if the interval is slightly changed due to variations in the thickness of the sealant, and bubbles may or may not remain even if the liquid crystal spreads slightly. In addition, when the opposing substrates are pressure-bonded so that the liquid crystal dropped in the central part spreads in a ripple pattern uniformly, reproducibility is ensured so that the liquid crystal does not go over the sealant and stain the adhesive surface, stick out, or leave bubbles. It was difficult to manufacture well and was not put into practical use.

As described above, the present invention provides a manufacturing method for enabling uniform and reproducible production of bubbles without remaining, and realizing a simpler dropping method than the injection method mainly used at present. .

Means for Solving the Problems In order to solve this problem, the present invention places a precisely weighed amount of liquid crystal inside a sealant provided on one substrate, and the liquid crystal diffuses to surround the liquid crystal. Before reaching the end face of the sealant, the other substrate facing the sealant is superposed so as to contact the top face of the sealant, decompressed and pressure-bonded, and then the sealant is solidified.

In the present invention, a sealant made of an adhesive or the like is printed on a substrate to a required thickness, a liquid crystal is precisely weighed in which the amount to be enclosed is placed, and when a counter substrate is placed on it, it is pressed. It is necessary that the expanded liquid crystal does not stick to the upper surface of the sealant or overflow from the seal. If such a state occurs, the adhesion of the seal adhesive to the substrate becomes insufficient, liquid crystal leaks, and the sealing performance becomes insufficient, resulting in impaired reliability. Therefore, it is a necessary condition that the expanding liquid crystal comes into contact with the inner surface of the sealant and the lower surface of the counter substrate overlapping with the upper surface of the sealant. Therefore, in order to prevent the spreading speed from becoming too fast, it is effective to bond the liquid crystal in a state where the height of the liquid crystal is slightly higher than the thickness of the sealant.

The next point is to ensure that the extruded and expanded liquid crystal reaches each part of the inner surface of the sealant almost at the same time. In this way, when vacuum or reduced pressure is applied, air bubbles remain. The possibility can be greatly reduced. As a method of embodying these, the upper and lower substrates are aligned and kept parallel to each other so that the upper surface of the sealant comes into contact with the lower surface of the counter substrate and the spread liquid crystal has a distance such that it comes into contact with the end surface of the sealant. A required amount of liquid crystal may be placed in a shape substantially similar to the sealant. Further, in order to make it difficult for bubbles to remain, it is also effective to make each inner corner portion of the sealant into a curved surface instead of a right angle.

Generally, the shape of the sealant is rectangular, so as a method of providing a liquid crystal that is precisely weighed so that it is rectangular with equal dimensions separated from the inside surface of the sealant, a droplet is dropped into a dot from a thin pipe and the aggregate is dispersed. Choose from a practically convenient method such as making the body rectangular, or applying a required amount of liquid crystal that is slightly thicker than the thickness of the sealant and precisely weighed by the screen method or blade method. Good. Further, instead of printing an adhesive resin as a sealant and using it, a film having an adhesive layer on both sides and having a constant thickness and a sealant shape may be used. The sealant used here may be one in which a spacer is included in order to constantly and uniformly regulate the distance between the counter electrodes of the liquid crystal panel, or the spacer may be included in the liquid crystal,
Even if a spacer is interposed between both substrates by a conventionally known method, the same effect can be obtained.

Operation With this configuration, the liquid crystal does not contaminate the adhesive between the sealant and the substrate, does not overflow, and does not leave any bubbles inside. Can be

Examples Hereinafter, specific examples of the present invention will be described.

Example 1 As shown in FIGS. 1A and 1B, 180 × 8 was formed on a glass substrate 2 on which a patterned transparent electrode 1 of 200 × 300 × 1.1 (mm) was formed.
Sealing agent 4 made of UV-curable resin adhesive with a width of 0 (mm), a width of 1 mm and a spacer with a diameter of 8 μm mixed in 8.
Screen-printed to a thickness of 5 μm and precisely weighed inside 0.8 mg
The liquid crystal 3 is dropped so that the liquid crystal 3 is located within 5 mm from the inner surface of the sealant 4, and the glass substrate 2 ′ facing the glass substrate 2 ′ in that state.
While aligning the two boards, align and stack them. Next, this is pressure-bonded while being in a vacuum or reduced pressure state, and ultraviolet rays are irradiated to cure the sealant 4. In this case, the amount of the liquid crystal 3 is determined according to the desired gap, and in order to further improve the accuracy, precisely weighed as shown in FIG. The method shown in FIG. 2A is also effective. Although various technical improvements can be made to this dropping method in order to make the bubbles even and to prevent bubbles from remaining, in the conventional method of hanging at the central portion and crimping, as shown in FIG. 3A. As described above, the pattern spreads in a ripple pattern, and the shape is also irregular and the filling condition of the corner portion is different each time. Therefore, when the pressure bonding is performed under the same condition, bubbles remain and the defective rate becomes high. On the other hand, according to the present invention, as shown in FIG. 3B, the corners are filled while the almost same state is maintained, so that bubbles are less likely to remain and the dropping method can be put to practical use with high yield.

(Example 2) Instead of screen-printing the seal adhesive of Example 1, a 6 μm-thick polyester film having adhesive layers on both sides cut out in the same shape as the seal agent was used as a seal and spacer. In this case, the same effect was obtained.

EFFECTS OF THE INVENTION As described above, according to the present invention, liquid crystal does not contaminate the adhesive surface of the sealant, does not overflow outside the sealant, and does not leave air bubbles, and can be manufactured with high yield. Is.

As a result, compared to the injection method that is generally used in the past, the injection sealing process is not required, which makes it possible to streamline production by shortening the manufacturing process and shorten the lead time. Is significantly reduced,
Many effects such as cost reduction and drastic reduction of injection time can be obtained. These are also effective for general varieties, but large-sized ones, for which demand is expected to grow further in the future,
It is even more effective in the manufacture of high-precision liquid crystal display elements, and its industrial value is great.

[Brief description of drawings]

1A and 1B are perspective views and cross-sectional views showing a manufacturing method of a liquid crystal display device according to an embodiment of the present invention, and FIGS. 2A and 2B are plan views showing a manufacturing process of the manufacturing method. 3A and 3B are explanatory views for explaining the effect of the present invention, FIG. 4 is a sectional view of a general liquid crystal display element, and FIG. 5 is a schematic view for explaining a conventional manufacturing method. 1,1 '... Transparent electrode, 2,2' ... Glass substrate, 3 ... Liquid crystal, 4 ... Sealant.

Claims (6)

[Claims] 1. Inside the sealant provided on one of the substrates,
Place a precisely weighed amount of liquid crystal on it, stack it so that the other opposing substrate is in contact with the top surface of the sealant until the liquid crystal diffuses and reaches the peripheral edge of the sealant, decompress and press-bond, then seal. A method for manufacturing a liquid crystal display element, which comprises solidifying an agent. 2. The liquid crystal placed on the substrate is diffused, and the liquid crystal is distributed and dropped so that the required time for reaching the inner surface of each side of the sealant is the same.
A method for manufacturing a liquid crystal display element according to the item. 3. The method for producing a liquid crystal display device according to claim 1, wherein a constant amount of liquid crystal is dropped as a multi-point aggregate having a small-sized similarity to the sealant. 4. The liquid crystal according to claim 1, wherein the liquid crystal of which the required amount is precisely weighed is applied slightly thicker than the sealing agent on the substrate so that the sealing agent has a small similar shape to the sealing agent. Manufacturing method of display device. 5. A method of manufacturing a liquid crystal display device according to claim 1, wherein a sealant having a spacer therein is used. 6. The method for producing a liquid crystal display device according to claim 1, wherein a film having an adhesive layer on both sides thereof is used as the sealing agent.