JPH0943613A - Production of liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strength of adhesion of adhesive pieces and to shorten the time for a curing treatment of sealants for liquid crystal cells by mounting heating elements at a pair of electrode substrates and curing the sealants for liquid crystal cells and the adhesive pieces by heating a pair of these electrode substrates by the heat generated by the heating elements. SOLUTION: The sealants 7 for the liquid crystal cells contg. one pack type thermoplastic epoxy adhesives for enclosing the liquid crystal cells with the sealants themselves and the adhesives and the adhesive pieces 8 of a hot melt type contg. thermosetting epoxy adhesives for spot adhering the electrode substrates 1a, 1b are mounted at least at either side of the opposite surfaces of a pair of the electrode substrates 1a, 1b arranged to face each other. While the respective electrode substrates 1a, 1b stuck to each other are pressurized by air pressures, the heat generated by the respective heating elements 4a, 4b is transmitted via heat plates 3a, 3b and cushion materials 2a, 2b to the respective electrode substrates 1a, 1b, by which the sealants 7 for the liquid crystal cells and the adhesive pieces 8 are cured.

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 device, and more particularly to a liquid crystal cell sealing agent for sealing liquid crystal between a pair of opposing electrode substrates and an adhesive bead for spot-bonding the pair of electrode substrates. The present invention relates to a method for manufacturing a liquid crystal element having a curing step.

[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 or the like is used. There are ways.

[0004]

However, since the pressure jig which uses the weight, the air pressure, and the spring load for suppressing the distortion of the electrode substrate has a large heat capacity itself, for example, in a oven set at 160 ° C. It takes about 3 hours for the temperature of the electrode substrate in the introduced air pressure jig to reach 150 ° C. As described above, there are the following problems in curing in a temperature profile in which the rate of temperature rise is very slow.

(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.
Although heat treatment at 50 ° C. for about 1 hour is required, the above-described conventional curing method requires heat treatment time for curing (about 1 hour), heating time (about 3 hours), and cooling time. Therefore, a long processing time is required from the loading of the electrode substrate to the removal thereof.

Further, according to the conventional curing method of placing an electrode substrate in a pressure jig and putting it in an oven, a large pressure jig and an oven are used for the pressure and heat treatment of a large area electrode substrate. Therefore, the cost becomes high.

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

[0009]

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 spot-bonding the pair of electrode substrates are attached to bond the pair of electrode substrates, and the pair of electrode substrates are heated and pressed. In a method of manufacturing a liquid crystal element having at least a curing step of curing the liquid crystal cell sealant and the 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. The electrode substrate is heated to cure the adhesive bead.

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

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

[0012]

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, 1
On the upper part of b, a metal material 5 for air pressure receiving, which is made of aluminum or the like and is pressed by air pressure through the cushioning material 2a, the heat plate 3a, the heating element 4, the heat plate 3b, and the cushioning material 2b, is placed. To be done. The metal material 5 has a uniform thickness and can uniformly transmit the received air pressure to the electrode substrates 1a and 1b.

Also, the electrode substrates 1a, 1 located at the bottom
The cushioning material 2a, the heat plate 3a, the heating element 4, the heat plate 3b, and the cushioning material 2 are also provided between the pressure table 6 and the lower part of b.
b is installed.

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,
The electrode substrates 1a and 1b are installed to equalize the pressure applied by the air pressure.

The heat plates 3a and 3b are for uniformly transmitting the heat generated by the planar heating element 4 disposed between them to the electrode substrates 1a and 1b, and are made of an aluminum material or the like having good heat conductivity. Is formed by.

As described above, in the step of curing the sealant for liquid crystal cells and the adhesive bead in the method for manufacturing a liquid crystal element according to the embodiment of the present invention, each electrode substrate 1 bonded together
While heating a and 1b with air pressure, the heat generated by each heating element 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.

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.

[0023]

Example 1 In the curing process of the liquid crystal cell sealant and the adhesive bead described above, a pair of electrode substrates 1a and 1b are provided.
On one of the glass substrates (plate thickness: 1.1 mm, size: 300 mm x 320 mm) constituting the liquid crystal cell, a sealant for a liquid crystal cell (for example, manufactured by Mitsui Toatsu Chemicals, Inc.
Product name: Struct Bond XN-21-F) is printed,
After that, 1 mm of an adhesive bead having an average particle size of about 5.6 μm (for example, manufactured by Toray Industries, Inc., trade name: Trepearl Type III) is used.
Spraying was carried out at an average density of 170 pieces per ² pieces.

A spacer having an average particle diameter of about 1.04 μm (for example, manufactured by Catalyst Kasei Kogyo Co., Ltd., trade name: on the other glass substrate (thickness is 1.1 mm) constituting the 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.

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 same buffer material 2a, the heat plate 3a, and the heating element 4 provided on the uppermost electrode substrates 1a and 1b are provided. , Heat plate 3b, cushioning material 2
A metal material (aluminum plate having a plate pressure of 8 mm) 5 that receives air pressure is placed on b.

Then, these are set in an air pressure type jig (not shown), and pressure is applied to each electrode substrate 1a, 1b by air pressure (1 kg / cm ² ) to energize each heating element 4. To heat up.

At this time, the heat generation of the heating element 4 is adjusted by the connected temperature sensor (not shown) and temperature controller (not shown) so that the temperature of the heat plate 3b in contact therewith is maintained at 160.degree. To do.

The heat generated by each heating element 4 is transferred to each of the electrode substrates 1a and 1b via the heat plates 3a and 3b and the buffer materials 2a and 2b, respectively, so that the temperature of the electrode substrates 1a and 1b is 1%.
It took 10 to 15 minutes to reach 50 ° C. afterwards,
After the electrode substrates 1a and 1b are held at 150 ° C. for 1 hour, the heating element 4 is turned off and naturally cooled, and then the electrode substrates 1a and 1b are taken out from the jig (not shown). .

Then, the electrode substrates 1a and 1b are set to 35 mm.
After cutting into corners, the adhesive strength of the adhesive bead 8 was measured by a shearing method. Table 1 shows the measurement results showing the adhesive strength of the adhesive bead 8 at this time.

[0031]

[Table 1] Then, in order to compare the adhesive strength of the adhesive bead 8 according to the present embodiment described above with the adhesive strength of the adhesive bead in the curing process of the conventional liquid crystal cell sealant and adhesive bead, the following comparisons are made. I made a sample.

In this comparative sample, a pair of electrode substrates formed by the same method as in the above-mentioned Example 1 was laminated, and the electrode substrates and the buffer material were alternately laminated and set in an oven. Against this, after pressurizing with air pressure (1 kg / cm ² ) by an air pressure type jig,
Keep warm at 0 ° C.

In this case, the temperature of this electrode substrate is 150 ° C.
It took about 3 hours to reach. Then this 150
The electrode substrate is taken out after being kept at a temperature of ° C for 1 hour and then naturally cooled.

Then, this electrode substrate was cut into a 35 mm square and the adhesive strength of the adhesive bead was similarly measured by the shearing method. Table 2 shows the measurement results showing the adhesive strength of the adhesive bead at this time.

[0035]

[Table 2] As is clear from this comparison result, Example 1 shown in Table 1
In the adhesive bead in, the heat generated by the heating element 4 is transmitted through the heat plate 3a and the cushioning materials 2a, 2b to the electrode substrates 1a, 1
By directly transferring heat to the entire surface of b, the electrode substrate 1
Since the temperature distributions of a and 1b are uniform and the temperature rising time is short, stable strong adhesive strength (shear strength) is obtained for each sample.

On the other hand, in the adhesive bead produced by the conventional curing process prepared for comparison shown in Table 2, the temperature is higher on the outside of the electrode substrate than on the inside of the electrode substrate (the temperature distribution is In addition, since the temperature rise time is slow, there is a portion with extremely low adhesive strength, and the adhesive strength (shear strength) of the sample (Sample No. 1 and 2 in Table 2) cannot be measured. It was possible, and the average value of the adhesive strength (shear strength) of each sample was also lower than that of Example 1.
The average value of the adhesive strength of the adhesive bead according to the conventional process shown in Table 2 is a value only for the adhesive strength (shear strength) that can be measured.

(Embodiment 2) In this embodiment, a liquid crystal cell is screen-printed on one glass substrate (plate thickness: 1.1 mm) constituting each pair of electrode substrates 1a and 1b in FIG. Sealant (for example, manufactured by Mitsui Toatsu Chemical Co., Inc., trade name: Structbond XN-21-F) is printed, and then an adhesive bead having an average particle size of about 5.6 μm (for example,
Toray's trade name: Trepearl Type III) was sprayed at an average density of 80 pieces per 1 mm ² .

A spacer having an average particle diameter of about 1.04 μm (for example, a product name of 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.

Then, after the electrode substrates 1a and 1b are cured by the same method as in Example 1, a pyrimidine-based ferroelectric liquid crystal exhibiting the following phase transition temperature is injected, and as shown in FIG. A liquid crystal panel 10 was created.

[0041] Then, the liquid crystal panel 10 which is electrically mounted according to the above-described embodiment and the electrode substrate bonded by the conventional method for curing the liquid crystal cell sealant and the adhesive bead of the first embodiment,
A shock resistance test with a liquid crystal panel of a comparative sample prepared by injecting the above-mentioned ferroelectric liquid crystal and performing electrical mounting was performed at 50 G.
The drop test was performed.

As a result of this drop test (shock resistance test), no disorder was observed in the alignment of the liquid crystal of the liquid crystal panel 10 according to this example. However, as shown in FIG. Disturbance occurred in the alignment of the liquid crystal located on both sides 11a, 11b (hatched portions).

As described above, the curing process of the liquid crystal cell sealant and the adhesive bead according to the present embodiment shortens the curing time and increases the adhesive strength of the adhesive bead to increase the impact resistance of the liquid crystal element. It is possible to improve the sex.

Further, the heating element 4 is provided on the pair of electrode substrates 1a and 1b without using the heat plates 3a and 3b.
The electrode substrates 1a and 1b may be heated by installing them via a and 2b.

[0045]

As described above, according to the present invention,
In the process of curing the liquid crystal cell sealant and the 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 heat generator to cure the liquid crystal cell sealant and the adhesive bead. Thereby, the entire surface of the electrode substrate is uniformly heated, and the temperature rising time can be shortened.

Therefore, by obtaining a sufficient adhesive strength of the adhesive bead, it is possible to enhance the impact resistance of the liquid crystal element to be produced, and by shortening the curing processing time, the liquid crystal element The manufacturing efficiency can be improved.

Further, since it is only necessary to use a heating element suitable for a large-area electrode substrate, equipment such as a large oven for heating the electrode substrate unlike the prior art is not required, resulting in cost reduction. It can be reduced.

[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 schematically showing disorder of liquid crystal alignment due to a drop test of a liquid crystal panel prepared for a comparative sample.

[Explanation of symbols]

 1a, 1b Electrode substrate 2a, 2b Buffer material 3a, 3b Heat plate 4 Heating element 5 Metal material 7 Liquid crystal cell sealant 8 Adhesive bead 10 Liquid crystal panel

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, the heating step is attached to the pair of electrode substrates in the curing step, and the pair of electrode substrates is heated by the heat generated by the heating elements to cure the adhesive bead. Liquid crystal device manufacturing method. 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.