JPS63179323A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To easily prepare a liquid crystal display element which has a liquid crystal having good reproducibility uniformly without allowing air bubbles to remain in the liquid crystal by placing the accurately weighed liquid crystal to a required shape on the inside of a sealing agent of one substrate and diffusing the liquid crystal by an opposite substrate. CONSTITUTION:A required amt. of the accurately weighed liquid crystal 3 is dropped to approximately the same shape as the inside shape of the sealing agent 4 on the inside of the sealing agent 4 of the glass substrate 2. The liquid crystal 3 is uniformly diffused to the inside of the sealing agent 4 without allowing the air bubbles to remain therein and without flowing over the agent 4 when the opposite glass substrate 2' is superposed on the above-mentioned substrate so as to contact the front surface of the agent 4. The liquid crystal display element which has the liquid crystal having the good reproducibility uniformly without allowing the air bubbles to remain therein is easily prepd. when the agent 4 is cured after pressure reduction and compression bonding.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method for manufacturing a liquid crystal display element.

Conventional liquid crystal display elements generally have patterned transparent electrodes 1+1'?, as shown in FIG. Two glass substrates 2 and 2'f on each surface are placed opposite each other, a liquid crystal 3 is interposed between them, and the peripheral portion is fixed with a sealant 4, and polarizing plates 6 and 6' are provided on both surfaces. In the case of a reflective type, a reflective layer 6 made of aluminum or the like is further formed on one outer side.

Here, as a method for interposing the liquid crystal 3 between the two glass substrates 2 and 2', as shown in the perspective view of FIG. ``The other glass substrate 2'' facing with the sealant 4 provided thereon.
After pasting them together and injecting the liquid crystal 3 from the liquid crystal injection port 4',
The method used is to seal it with adhesive or the like and cut it into pieces of the required size (hereinafter referred to as the injection method).

In addition, after forming a sealant without an injection port, the required amount of liquid crystal 3 is dropped onto the center of the sealant, and the opposite glass substrate 2
A method of laminating and fixing the materials has also been proposed, but there are many difficulties in production technology, and this method has not been put to practical use (hereinafter referred to as the dropping method).

Problems to be Solved by the Invention The injection method generally injects by reducing the pressure with the injection port in contact with the liquid crystal in the liquid crystal reservoir, which wastes several times the amount of expensive liquid crystal that is required for injection. As the overall size and shape increase, it takes an extremely long time to inject into a large area with thin spacing of several micrometers, and there are many difficulties in terms of production efficiency. Also, when sealing the injection port, if the adhered liquid crystal is not thoroughly wiped off, the sealing adhesive strength will be insufficient.
Excessive wiping tends to cause air bubbles, so careful control was required in terms of production technology.

As a means to solve these problems, a drip method has been considered and various proposals have been made. However, with this method, a sealant layer is formed using adhesive or the like around the periphery, and the necessary amount of liquid crystal is placed inside and cured by pressure.
In this case, since the spacing between the inner substrates is as thin as several μm, the required amount of liquid crystal is several hundred η even for a size of, for example, 200×300−.
A very small amount must be weighed accurately. Even if the spacing changes slightly due to variations in the thickness of the sealant, bubbles tend to remain, and even if there is a slight difference in the degree of spread of the liquid crystal, bubbles may or may not remain. 1) When pressing the opposing substrates so that the liquid crystal dropped in the center spreads uniformly in a ripple pattern, make sure that the liquid crystal does not cross over the sealant and stain the adhesive surface, protrude, or leave bubbles. It is difficult to manufacture with good reproducibility and has not been put into practical use.

The present invention provides a manufacturing method that enables uniform and reproducible manufacturing without leaving any bubbles, and enables a drop method that is simpler than the injection method currently mainly used. .

Means for Solving the Problem In order to solve this problem, the present invention places a precisely measured amount of liquid crystal on the inside of a sealant provided on one substrate, and this liquid crystal diffuses into the surrounding area. By the time the sealant reaches the end surface of the substrate, the other opposing substrate is placed in contact with the top surface of the sealant, and the pressure is reduced.

After crimping, the sealant is solidified.

In the present invention, when a sealant made of adhesive or the like is printed to a required thickness on a substrate, a precisely measured amount of liquid crystal to be sealed is placed inside the sealant, and a counter substrate is placed on top of the sealant, it is not pressed. It is necessary that the liquid crystal that has spread out does not get on the top surface of the sealant or overflow outside the seal. If this happens, the sealing adhesive may not adhere well to the substrate and the liquid crystal may leak, or the sealing performance may become insufficient, reducing reliability. It is a necessary condition that the upper surface of the sealant and the lower surface of the counter substrate to be overlapped are in contact with each other. In order to prevent the liquid crystal from spreading too quickly, 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 make sure that the extruded and expanded liquid crystal reaches each part of the inner surface of the sealant almost simultaneously. This can greatly reduce the possibility of remaining. As a method of realizing these, the upper and lower substrates are aligned and parallel to each other, and the bottom surface of the opposing substrate touches the top surface of the sealant, and then the distance is such that the expanded liquid crystal touches the end surface of the sealant. All you have to do is place the required amount of liquid crystal in a shape that is almost similar to the sealant. Furthermore, in order to make it difficult for air bubbles to remain, it is also effective to make a portion of each inner corner of the sealant a curved surface instead of a right angle.

Generally, the shape of the sealant is rectangular, so one way to provide a liquid crystal accurately weighed in a rectangular shape at equal distances from the inner surface of the sealant is to drop it in dots from a thin pipe.
Practical methods include a method in which the points form a rectangular shape as a diffused aggregate, and a method in which the required amount of liquid crystal, which is slightly thicker than the thickness of the sealant, is precisely weighed into the shape using a screen method or blade method. Just choose the one that is convenient for you.

Moreover, instead of printing and using an adhesive resin as a sealant, a film shaped like a sealant with adhesive layers provided on both sides and having a constant thickness may be used. The sealant used here may include a spacer embedded therein in order to always regulate the distance between opposing electrodes of the liquid crystal panel to be constant and uniform, or may include a spacer embedded within the liquid crystal, or a The same effect can be obtained by interposing spacers between the inner curtain plates using the method described above.

Function: With this configuration, the liquid crystal does not contaminate or overflow the adhesive surface between the sealant and the substrate, and no air bubbles remain inside, making it possible to put into practical use the dropping method, which had many practical difficulties until now. can do.

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

(Example 1) As shown in Figure 1 and B, 200X300X1.1 (a
+m) Glass substrate 2 on which a patterned transparent electrode 1 is formed
180 x 80 (mm), width 1 mm, and 8
A sealing agent 4 made of an ultraviolet curable resin adhesive with a spacer of μm diameter mixed therein is screen printed to a thickness of 8.6 μm, and a liquid crystal 3 of 0.8 ■ weighed precisely is placed inside the sealing agent 4.
Drop it so that it fits within 6mm from the inner surface,
In this state, the opposing glass substrates 2' are aligned and stacked while keeping the inner curtain plates parallel. Next, this is pressed under vacuum or reduced pressure and irradiated with ultraviolet lfM to harden the sealant 4. In this case, the amount of liquid crystal 3 is determined depending on the desired gap, but in order to further improve the accuracy, as shown in Fig. 2B, it is precisely weighed and dripped in dots one after another or all at once, and the liquid crystal 3 is dispersed. The method of doing things like the person in Figure 2 is also effective. In order to ensure uniformity and no bubbles, this method of dropping can be improved in various ways, but the conventional method of dripping and crimping in the center, Spreading in ripples like a person9,
Its shape is also irregular, and the filling condition of a corner differs each time, so if vacuum crimping is performed under the same conditions, air bubbles remain and the defective rate increases. On the other hand, according to the present invention, FIG.
Since the liquid is filled to the corners while maintaining almost the same state as shown in FIG.

(Example 2) Instead of screen printing the sealing adhesive of Example 1, a 6 μm thick polyester film with adhesive layers on both sides was cut out in the same shape as the sealing agent and used as a seal and spacer. Similar effects were obtained in this case as well.

As described in detail, according to the present invention, the liquid crystal can be manufactured at a high yield without contaminating the adhesive surface of the sealant or spilling out of the sealant, and without leaving bubbles. It is possible.

As a result, compared to the injection method commonly used in the past, ■ the process of sealing the injection port is no longer necessary, making it possible to rationalize production and shorten lead time by reducing the manufacturing process; The loss of clothes is greatly reduced,
Many benefits can be obtained, including the ability to reduce costs and ■ significantly shorten the time required for injection. These are also effective for general varieties, but
It will be even more effective in manufacturing large, high-precision liquid crystal display elements, for which demand is expected to increase further in the future, and its industrial value is great.

[Brief explanation of the drawing]

1A and 1B are perspective views and sectional views of essential parts showing a method of manufacturing a liquid crystal display element according to an embodiment of the present invention; FIGS. 2A and 2B are plan views showing main steps of the same manufacturing method; 3A and 3B are explanatory diagrams for explaining the present invention in detail, FIG. 4 is a sectional view of a general liquid crystal display element, and FIG. 5 is a schematic diagram for explaining the conventional manufacturing method. 1.1'...Transparent electrode, 2,2'...Glass substrate, 3...Liquid crystal, 4...Sealing agent. Name of agent: Patent attorney Toshio Nakao (1 person)
/'--Toichiroden'' 54--Nuru 9I

Claims (6)

[Claims] (1) Place the required amount of precisely weighed liquid crystal on the inside of the sealant provided on one substrate, and by the time this liquid crystal diffuses and reaches the edge of the sealant around the other substrate, the opposite substrate is sealed. A method for manufacturing a liquid crystal display element, which comprises stacking the sealant so that it is in contact with the upper surface of the sealant, reducing the pressure, and crimping the sealant, and then solidifying the sealant. (2) The liquid crystal placed on the substrate is distributed and dropped so that the time required for the liquid crystal to diffuse and reach the inner surface of each side of the sealant is the same, as described in claim 1. A method for manufacturing a liquid crystal display element. (3) A method for manufacturing a liquid crystal display element according to claim 1, characterized in that the liquid crystal is dropped in a fixed amount in the form of a multi-dot aggregate having a small similar shape to the sealant. (4) A liquid crystal display according to claim 1, characterized in that the required amount of liquid crystal is precisely weighed and applied onto the substrate slightly thicker than the sealant so that the liquid crystal has a smaller size similar to the sealant. Device manufacturing method. (5) A method for manufacturing a liquid crystal display element according to claim 1, characterized in that a sealant having spacers therein is used. (6) A method for manufacturing a liquid crystal display element according to claim 1, characterized in that a film having a constant thickness and having adhesive layers on both sides is used as the sealant.