JPH0961830A - Production of liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent such problems that enough adhesion strength of adhesive beads can not be obtd. and that a long time is required for the hardening treatment of a sealing agent for a liquid crystal cell. SOLUTION: A heat generating body 4 is attached with buffer materials 2a, 2b and heat plates 3a, 3b to a pair of electrode substrates 1a, 1b to transfer the heat generating from the heat generating body 4 through the heat plates 3a, 3b and the buffer materials 2a, 2b to the pair of electrode substrates 1a, 1b. Thus, the electrode substrates are heated at 1.0-4.0 deg.C/min. rising rate to harden a sealing agent 7 for a liquid crystal cell and adhesive beads 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal element, and more particularly, to a liquid crystal cell sealant for enclosing a liquid crystal between a pair of opposing electrode substrates and a curing agent bead for adhering the pair of electrode substrates. The present invention relates to a method for manufacturing a liquid crystal element having steps.

[0002]

2. Description of the Related Art Conventionally, a method for curing a liquid crystal cell sealant and an adhesive bead for adhering a pair of electrode substrates has been such that a pair of electrode substrates are superposed and aligned, and then the electrode substrates are distorted due to thermal expansion during heating. In order to suppress the pressure, press the entire surface of the electrode substrate with a pressure of 0.1 to 5.0 kg / cm ² and
A general method is to cure in an oven set to 0 to 200 ° C.

As a pressing method for suppressing the distortion of the electrode substrate at this time, for example, a pressing method using a weight for applying a weight to the entire surface of the electrode substrate or a pressing jig using air pressure, spring load, etc. is used. There are ways.

[0004]

However, since the weight, the air pressure, and the spring-loaded pressing jig for suppressing the distortion of the electrode substrate have a large heat capacity, the heating jig has a large heat capacity. It takes about 3 hours for the temperature of the electrode substrate in the air pressurizing jig introduced in step 1 to reach 150 ° C.

Thus, the rate of temperature rise in the oven is
Depending on the size of the substrate to be used, the number of substrates to be processed, the pressure applied and the specifications of the pressure jig, for example, 500 x 500 m
When processing a large substrate of m-square level, generally 0.3
It is about 0.7 ° C./min.

Further, there is the following problem in the curing in the temperature profile in which the temperature rising time is very slow as in the conventional case.

(1) Before the hot-melt type adhesive bead is sufficiently melted, the curing reaction between the curing agent and the epoxy adhesive in the adhesive bead proceeds, and so-called wetting does not occur at the interface with the electrode substrate. However, sufficient adhesive strength cannot be obtained. In such a state, impact resistance may be lowered particularly in the ferroelectric liquid crystal element.

(2) About 1 is required to cure the liquid crystal cell sealant.
Heat treatment at 50 to 160 ° C for about 1 hour is required,
In the above-mentioned conventional curing method, a heat treatment time (about 1 hour) for curing, a temperature raising time (about 3 hours) and a cooling time are required, and it takes a long time to process the electrode substrate until it is taken out. Requires.

Further, according to the conventional curing method in which an electrode substrate is placed in a pressure jig and is put in an oven, a large pressure jig and an oven are used for pressurizing and heating a large area electrode substrate. Therefore, the cost becomes high.

Therefore, it is an object of the present invention to provide a method of manufacturing a liquid crystal element, which can shorten the curing treatment time of a liquid crystal cell sealant and obtain a sufficient adhesive strength of an adhesive bead.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, in which the pair of electrode substrates and the pair of electrode substrates are provided on the bonding surfaces of the pair of opposing electrode substrates into which liquid crystal is injected. A liquid crystal cell sealant for enclosing the liquid crystal with itself, and an adhesive bead for adhering the pair of electrode substrates are attached to bond the pair of electrode substrates, and the pair of electrode substrates are heated and pressurized to In a method of manufacturing a liquid crystal element having at least a curing step for curing a liquid crystal cell sealant and an adhesive bead, in the curing step, a heating element is attached to the pair of electrode substrates, and the pair of electrodes is heated by the heating element. Electrode substrate 1.0 to 4.0 ℃ / mi
It is characterized in that the adhesive bead is cured by heating at a temperature rising rate of n 2.

Further, preferably, the heating element is formed in a planar shape and has a size corresponding to the electrode substrate.

Further, preferably, the heating element is attached to both surfaces of the pair of electrode substrates through a heater plate for soaking and a cushioning material.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing a step of curing a sealant and an adhesive bead in a method of manufacturing a liquid crystal element according to an embodiment of the present invention.

As shown in this figure, between each of the plurality of pairs of electrode substrates 1a, 1b arranged in multiple stages, the cushioning material 2a, the heat plate 3a, the planar heating element 4, and the heat plate are arranged in order from the bottom. 3b and cushioning material 2b are installed. The heat plate 3a and the planar heating element 4 are formed to be slightly larger than the electrode substrates 1a and 1b, and the cushioning material 2
a, 2b, the heat plate 3b, the electrode substrate 1a, 1b
It is formed with almost the same size as.

Further, the uppermost electrode substrates 1a, 1a
A weight 5 made of an aluminum material for pressurization is placed on the upper part of b via the cushioning material 2a, the heat plate 3a, the heating element 4, the heat plate 3b, and the cushioning material 2b, and the electrode substrate located at the lowermost position. The cushioning material 2a, the heat plate 3a, the heating element 4, the heat plate 3b, and the cushioning material 2b are also installed between the pressure table 6 and the lower portions of the lamas 1a and 1b.

A pair of electrode substrates 1a arranged to face each other,
On at least one side of the facing surface of 1b,
A liquid crystal cell sealant 7 containing a one-pack type thermosetting epoxy adhesive for encapsulating a liquid crystal cell by itself, and a hot melt type containing a thermosetting epoxy adhesive for spot-bonding the electrode substrates 1a and 1b. Adhesive beads 8 are attached.

The cushioning materials 2a and 2b are thinly formed,
It is installed in order to equalize the pressure applied by the weights 5 to the electrode substrates 1a and 1b.

The heat plates 3a, 3b are for uniformly transmitting the heat generated by the planar heating element 4 arranged between them to the electrode substrates 1a, 1b, such as an aluminum material having good heat conductivity. Is formed by.

A temperature sensor (not shown) is connected to the heat plates 3a and 3b, and a temperature controller (not shown) is connected to the heating element 4, and the temperature information of the temperature sensor (not shown) is connected to the temperature information. By controlling a temperature controller (not shown) based on the above, the electrode substrates 1a, 1
The temperature rising rate of b can be adjusted.

In the present invention, the temperature rising rate of the electrode substrates 1a and 1b due to the heat generated by the heating element 4 is set within the range of 1.0 to 4.0 ° C./min.

As described above, in the curing process of the liquid crystal cell sealant and the adhesive bead in the method for manufacturing a liquid crystal element according to the embodiment of the present invention, the electrode substrates 1 bonded together are bonded.
While pressing the weights a and 1b with the weight 5, the heat generated by the heating elements 4 is transferred to the electrode substrates 1a and 1b through the heat plates 3a and 3b and the cushioning materials 2a and 2b, and the liquid crystal cell sealant 7 and The adhesive bead 8 is cured.

Electrode substrate 1 due to heat generation of heating element 4 at this time
The temperature rising rate of a and 1b is set to 3.0 ° C./min, for example.

Since the cushioning materials 2a and 2b are formed thin and the heat plates 3a and 3b have good heat conductivity, the heating element 4
It is possible to transfer heat to the electrode substrates 1a and 1b with almost no escape of heat.

Next, examples of the present invention will be described in detail.

[0027]

【Example】

(Example 1) In the curing process of the above-mentioned liquid crystal cell sealant and adhesive bead, each pair of electrode substrates 1a, 1b
On one of the glass substrates (a square with a side of 500 mm and a plate thickness of 1.1 mm) that composes the above, a sealant for liquid crystal cells (for example, Mitsui Toatsu Chemical Co., Ltd., trade name: Struct Bond XN) by screen printing -21-F) was printed, and thereafter, an adhesive bead having an average particle size of about 5.6 μm (for example, Toray Industries, Inc., trade name: Trepearl Type III) was sprayed at an average density of 170 pieces per 1 mm ² .

On the other glass substrate (a square having a side of 500 mm and a plate thickness of 1.1 mm) which constitutes the pair of electrode substrates 1a and 1b, a spacer having an average particle size of about 1.04 μm (for example, Catalyst Chemical Industry) is used. (Trade name: silica microbeads, manufactured by the company) was sprayed at an average density of 300 pieces per 1 mm ² .

Then, the two glass substrates were bonded together to form a pair of electrode substrates 1a and 1b.

As shown in FIG. 1, a cushioning material (for example, manufactured by Bridgestone Co., trade name: Everlight Scott Felt, thickness: 1 mm) 2a provided on the pressure table 6 and a heat plate (plate thickness: 1 mm aluminum plate 3a, planar heating element (for example, Sakaguchi Dentsu Co., Ltd., trade name: Samicon 230,
Watt density: 1W / cm ² ) 4, Heat plate (thickness is 3
mm aluminum plate) 3b, cushioning material (same as cushioning material 2a)
The lowermost electrode substrate 1a, 1b is placed on 2b, and a similar buffer is provided between the plurality of electrode substrates 1a, 1b installed between the uppermost electrode substrate 1a, 1b. The material 2a, the heat plate 3a, the heating element 4, the heat plate 3b, and the buffer material 2b are provided, and further, the buffer material 2a, the heat plate 3a, the heating element 4, and the heat provided on the uppermost electrode substrates 1a and 1b. A weight (aluminum plate having a plate pressure of 8 mm) 5 is placed on the plate 3b and the cushioning material 2b.

Then, these are set in an air pressure type jig (not shown), and pressure is applied to each electrode substrate 1a, 1b by the weight 5 and air pressure (1 kg / cm ² ). The heating elements 4 are energized to generate heat, and the electrode plates 1a, 3b, 3b
Heat 1b.

At this time, the temperature controller (not shown) is controlled on the basis of the temperature information of the temperature sensor (not shown) to adjust the temperature rising rate of the electrode substrates 1a, 1b due to the heat generation of the heating element 4, As shown in FIG. 2, the heat plate 3a,
3b (electrode substrate 1a, 1b) from room temperature (25 ℃) to 16
3.0 ° C / min heating up to 0 ° C
5 minutes), after that, it is kept at 160 ° C. for about 1 hour and then cooled (for example, natural cooling), and after completion of cooling, the electrode substrates 1a and 1b are taken out from a jig (not shown). By the way, when the temperature of the electrode substrates 1a and 1b is rapidly increased (pressurization rate of 5.0 ° C./min or more) during the pressurization and heating, the air expansion rate in the electrode substrates 1a and 1b due to the temperature rise is for liquid crystal cells. The pressure in the electrode substrates 1a, 1b rises as the velocity of the air that escapes from the opening (liquid crystal injection port) of the sealant rises, and the air in the electrode substrates 1a, 1b breaks the parts other than the openings. There is a risk that This breakage of the seal causes a defective injection in the subsequent liquid crystal injection step, and reduces the manufacturing yield.

Therefore, in order to check the yield at this time,
Fifty electrode substrates were prepared under the same conditions, but no seal breakage due to pressure increase during curing of the liquid crystal cell sealant did not occur.

Further, the electrode substrates 1a and 1b were cut into a 35 mm square, and the adhesive strength of the adhesive bead 8 was measured by the shearing method. Table 1 shows the measurement results showing the adhesive strength of the adhesive bead 8 at this time.

[0035]

[Table 1] Then, the electrode substrate 1a manufactured in the above-described embodiment,
In order to make a comparison with 1b, as shown in FIG. 3, an electrode substrate (heat plates 3a, 3b) made in the same manner as this example, which is a comparative sample, was heated from room temperature (25 ° C.) to room temperature (25 ° C.). The temperature was raised up to 160 ° C. at 5.0 ° C./min (heating time during this period was about 30 minutes). Other conditions are the same as those in the above-described first embodiment.

Then, in order to examine the yield at the time of pressurization and heating, 50 electrode substrates were prepared under the same conditions. As a result, 18 electrode substrates were sealed by the pressure increase during curing of the liquid crystal cell sealant. A tear occurred.

Further, this electrode substrate was cut into a 35 mm square and the adhesive strength of the adhesive bead was measured by the shearing method. Table 2 shows the measurement results showing the adhesive strength of the adhesive bead when heated at a heating rate of 5.0 ° C./min.

[0038]

[Table 2] As is clear from this comparison result, Example 1 shown in Table 1
The adhesive strength of the adhesive bead at the temperature rising rate of 3.0 ° C./min was almost the same as the adhesive strength of the adhesive bead at the temperature rising rate of 5.0 ° C./min of the comparative example shown in Table 2. Even if the temperature was lowered from 5.0 ° C / min to 3.0 ° C / min, there was no problem in the adhesive strength of the adhesive bead. Also, the adhesive strength of the adhesive bead was measured in the same manner by setting the temperature rising rate in the range of 1.0 to 4.0 ° C./min (not shown), but there is almost no difference from Example 1 shown in Table 1, and Also, there was no occurrence of breakage of the seal due to an increase in pressure during curing of the liquid crystal cell sealant.

Thus, the heating rate during heating is 5.0 ° C. /
At min (or around 5.0 ℃ / min or more), the seal breaks due to the pressure rise during the curing of the liquid crystal cell sealant, but when the temperature rising rate is set in the range of 1.0 to 4.0 ℃ / min, the liquid crystal cell seal It is possible to obtain sufficient adhesive strength without causing breakage of the seal due to pressure increase during curing of the agent.

Further, the heating of the electrode substrate is performed by the heat generation of the heating element 4 connected through the heat plates 3a and 3b and the cushioning materials 2a and 2b, so that the temperature rising rate is 1.0.
It can be easily controlled in the range of up to 4.0 ° C / min.

Since the rate of temperature rise of 1.0 to 4.0 ° C./min is higher than the rate of temperature rise by conventional oven heating, the temperature rise time can be shortened.

Furthermore, since it is only necessary to use a heating element suitable for a large-area electrode substrate, there is no need for conventional equipment such as a large oven for heating the electrode substrate, which results in cost reduction. It can be reduced.

(Embodiment 2) In this embodiment, in FIG. 1, a screen is formed on one glass substrate (each side having a square of 500 mm and a plate thickness of 1.1 mm) which constitutes a pair of electrode substrates 1a and 1b. Sealant for liquid crystal cells by printing method (for example, Mitsui Toatsu Chemical Co., Ltd., trade name: Structbond XN
-21-F) was printed, and thereafter, an adhesive bead having an average particle size of about 5.6 μm (for example, Toray Industries, Inc., trade name: Trepearl Type III) was sprayed at an average density of 170 pieces per 1 mm ² .

A spacer having an average particle size of about 1.04 μm (for example, a product name manufactured by Catalyst Kasei Kogyo Co., Ltd.) is formed on the other glass substrate (thickness is 1.1 mm) constituting each pair of electrode substrates 1a and 1b. : Silica micro beads) were sprayed at an average density of 300 per 1 mm ² .

Then, the two glass substrates were bonded together to form a pair of electrode substrates 1a and 1b.

The electrode substrates 1a and 1b were pressed and heated in the same manner as in Example 1 to be cured, and then a pyrimidine-based ferroelectric liquid crystal having the following phase transition temperature was injected to inject liquid crystals. 20 panels were prepared.

[0047] These 20 liquid crystal panels did not cause seal breakage due to pressure increase during curing of the liquid crystal cell sealant as in Example 1 described above, and had no problem in liquid crystal injection.

After electrical mounting on these liquid crystal panels, a drop test of 50 G was performed as a shock resistance test, but the liquid crystal orientation was not disturbed.

Then, in order to make a comparison with the liquid crystal panel according to the present embodiment described above, an electrode substrate prepared as a comparative sample of the embodiment 1 (heating conditions as shown in FIG.
20 liquid crystal panels as comparative samples were prepared in the same manner as in Example 2 by raising the temperature from room temperature (25 ° C.) to 160 ° C. at 5.0 ° C./min, and then holding at 160 ° C. for about 1 hour and then cooling. Created.

Then, 8 of these 20 liquid crystal panels suffered from seal breakage due to pressure increase during curing of the liquid crystal cell sealant, resulting in injection failure during liquid crystal injection. .

Further, an impact resistance test (drop test of 50 G) was conducted, but the alignment of the liquid crystal was not disturbed.

As described above, the liquid crystal panel according to the present embodiment has no manufacturing yield due to defective liquid crystal injection and is excellent in impact resistance.

[0053]

As described above, according to the present invention,
In the curing process of the liquid crystal cell sealant and adhesive bead, the heating elements are attached to the pair of electrode substrates, and the pair of electrode substrates are heated by the heat generated by the heating elements at a temperature rising rate of 1.0 to 4.0 ° C / min to produce a liquid crystal cell. By curing the adhesive sealant and adhesive bead, the curing process time can be shortened without causing seal breakage due to the pressure rise during the curing of the liquid crystal cell sealant, thus improving the manufacturing efficiency of liquid crystal elements. The adhesive strength of the adhesive bead can be ensured.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a step of curing a liquid crystal cell sealant and an adhesive bead according to an embodiment of the present invention.

FIG. 2 is a diagram showing heating conditions during curing of a liquid crystal cell sealant and an adhesive bead according to an example of the present invention.

FIG. 3 is a diagram showing heating conditions in a comparative sample with respect to an example of the present invention.

[Explanation of symbols]

 1a, 1b Electrode substrate 2a, 2b Buffer material 3a, 3b Heat plate 4 Heating element 5 Weight 7 Liquid crystal cell sealant 8 Adhesive bead

Claims (6)

[Claims] 1. A sealant for a liquid crystal cell, which seals the liquid crystal between the pair of electrode substrates and itself on a bonding surface of a pair of opposite electrode substrates into which liquid crystal is injected, and the pair of electrodes. A liquid crystal device having at least a curing step of attaching an adhesive bead for adhering substrates and bonding the pair of electrode substrates together, and heating and pressurizing the pair of electrode substrates to cure the liquid crystal cell sealant and the adhesive bead. In the manufacturing method, in the curing step, a heating element is attached to the pair of electrode substrates, and the pair of electrode substrates is heated by the heat generated by the heating element to 1.
A method for manufacturing a liquid crystal element, comprising: heating the adhesive bead by heating at a temperature rising rate of 0 to 4.0 ° C./min. 2. The method for manufacturing a liquid crystal element according to claim 1, wherein the heating element is formed in a planar shape and has a size corresponding to the electrode substrate. 3. The method of manufacturing a liquid crystal element according to claim 1, wherein the heating element is attached to both surfaces of the pair of electrode substrates via a heater plate for soaking and a buffer material. 4. The method for manufacturing a liquid crystal element according to claim 1, wherein a plurality of the electrode substrates are installed in multiple stages. 5. The method for manufacturing a liquid crystal element according to claim 1, wherein the sealant contains a one-component thermosetting epoxy adhesive. 6. The method of manufacturing a liquid crystal element according to claim 1, wherein the adhesive bead is a hot-melt type including a thermosetting epoxy adhesive for spot-bonding the pair of electrode substrates.