JPS5897024A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To prevent foaming of liquid crystals by injecting the liquid crystals at an ordinary temp. into a liquid crystal cell through the liquid crystal injecting port provided to said cell, sealing said port with a sealing material and hardening the sealing material in the stage of shrinking the liquid crystals under the conditions wherein the entire part of the liquid crystal cell is maintained at temp. lower tha the ordinary temp. CONSTITUTION:Transparent electrodes 1 and a sealing material 2 are set on glass substrates 4, 5 and a liquid crystal material 7 is injected through an injecting port 3. The liquid crystals 7 oozed to the outside through the port 3 are removed by blowing gaseous N2 and the port is sealed by silicone adhesive 8. These stages are executed at 25 deg.C ordinary temp. Thereafter the entire part of the liquid crystal is put into a thermostatic chamber kept at -5-15 deg.C for 4hr to allow the liquid crystals 7 to shrink. The adhesive 8 is sucked to the inside and harden in this stage. When the temp. for allowing the liquid crystals to shrink is kept at <=10 deg.C, the fraction defective by foaming of the liquid crystal cell is reduced by half and the yield is markedly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display element, and more particularly to an improvement in a method for sealing a liquid crystal material.

O@Ming's technical background and its problems Liquid crystal display elements generally consist of a pair of substrates made of glass or the like (transparent electrodes made of indium dioxide, tin oxide, etc. are deposited in a predetermined shape), A space formed by sealing the periphery with a sealing material such as low-melting point glass or EBOKI 7-based adhesive so as to have an interval of 10 μm (=injecting the liquid crystal material and then sealing the injection port with a sealing materialC) In this case, the liquid crystal material is injected from a part of the 7-ring material or from an injection port provided in the substrate.

Various methods are known for encapsulating liquid crystal materials.

The first method is to use clips to hold the glass material of the cell injected with liquid crystal material, apply pressure to push out part of the liquid crystal material from the injection port, wrap the extruded liquid crystal material, and use epoxy/resin. In this method, the clip is removed and the adhesive is partially injected into the cell. However, with this method, when the clip is removed, the deformation of the board is restored (because it acts in the direction of recovery). The internal pressure of the liquid crystal material tends to be low, and there is a disadvantage that a small gas source in the liquid crystal material grows into large bubbles during the operation of the liquid crystal cell.

The second method is to inject the liquid crystal material into the cell, then heat the cell to a temperature where part of the injected liquid crystal material is pushed out from the injection port.
(This method involves heating the cell twice, removing the extruded liquid crystal, and then cooling the entire cell to room temperature while sealing the injection port. However, this method is better than the J1 method, but still A drawback is that the small gas sources present in the liquid crystal material grow into bubbles 42 during liquid crystal cell operation.

Since air bubbles within the liquid crystal cell significantly reduce display quality, the generation of air bubbles must be avoided as much as possible.

QObjective of the Invention The object of the present invention is to provide a method for manufacturing a highly reliable liquid crystal display element by preventing the generation of bubbles in a liquid crystal material.

・Summary of the invention The present invention arranges a pair of substrates facing each other, provides a liquid crystal injection port in a part of the substrate or the substrate facing part, and injects a liquid crystal material between the pair of substrates from the injection port. In the method for manufacturing a liquid crystal display element by curing with a sealing material,
The method for manufacturing a liquid crystal display element is characterized in that the sealing material is cured after the injected liquid crystal material reaches a temperature lower than room temperature.

According to the present invention, the internal pressure of the liquid crystal material during operation always tends to be higher than that in a steady state, so even if there is a gas source in the liquid crystal material, the gas will overcome the internal pressure and grow into bubbles. There is no. Therefore, a liquid crystal display element with high flexibility can be obtained.

Embodiments of the invention A practical explanation will be given with reference to FIGS. 1 and 2.

A 20g In electrode (1) was formed on each inner surface, and an epoxy sealant (2) was applied to the periphery.
: By arranging and bonding a pair of glass substrates (4) (51) facing each other so as to form a liquid crystal injection port (3).

Forms a liquid crystal cell (liquid crystal cell memory). Liquid crystal material for glass substrate (7
) (The two contacting sides are subjected to alignment treatment in advance to make it easier to align the liquid crystal molecules, if necessary.

Next, after a liquid crystal material (7) is injected from the injection port (3) of the liquid crystal cell, the liquid crystal material protruding from the injection port (3) is removed by blowing nitrogen gas to flatten the injection port.

Thereafter, silicone resin adhesive (8) is applied so as to close the injection port (3). The work up to this point is done at room temperature 25"0.

Next, when the entire liquid crystal cell is placed in a thermostatic chamber 1 maintained at various temperatures in the range of -5°C to 15°C, the liquid crystal material (7) contracts and the adhesive (8) flows toward the injection port. The adhesive (8) is cured by being sucked in and left in this state for about 4 hours. The liquid crystal cell (however) is taken out of the thermostatic chamber and returned to room temperature (a liquid crystal display element is obtained from the second step).

Experiment 1 was used to confirm the reliability of liquid crystal display elements against bubble generation.
The test is conducted using the following compulsory test, which has been established since 2010.

In an atmosphere with a temperature of 80°C and a humidity of 90°C (2100 hours, then taken out and left in the atmosphere for 7 days.
& After that, sandwich the sample between two polarizing plates and observe the presence or absence of air bubbles from the meat #i (twice).

Lofts with a forced test (= bubble generation rate exceeding 50 inches) are being mounted (there is a high probability of two bubbles being defective).

Figure 2 shows the adhesive curing temperature and forced test yield (1
00% - foam generation rate).

As is clear from the figure, the liquid crystal display element according to the present invention, in which the adhesive is cured at a temperature lower than room temperature, has a high yield.
It can be seen that the reliability against bubble defects (2) increases.The reliability gradually increases from curing temperature below 15℃.
It is significantly high at 0°C. In the above embodiment, an epoxy adhesive was used as an example of the sealing material for the liquid crystal injection port, but similar effects can be obtained by using other low-temperature cured melon adhesives.

[Brief Description of the Drawings] Fig. 1 is a schematic cross-sectional view of a liquid crystal display element according to the present invention (2), and Fig. 2 is a schematic cross-sectional view of a liquid crystal display element according to the present invention (-- the relationship between the curing temperature of the adhesive of the liquid crystal injection port and the yield of the forced test). This is a diagram showing ?S...Adhesive

Claims (1)

[Claims] A pair of substrates are arranged to face each other, a liquid crystal injection port is provided in a part of the substrate or the substrate facing part, and a liquid crystal material is injected between the pair of substrates from the injection port. In the method for manufacturing a liquid crystal display element by curing with a sealing material, the curing of the sealing material is performed after the injected liquid crystal material reaches a temperature lower than room temperature. Method.