JPH07128674A - Liquid crystal display element manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] A simple method is used to prevent and eliminate impurity ions from entering the liquid crystal, and to reduce drop traces, uneven threshold values, and uneven injection. [Structure] Immediately before dropping the liquid crystal 11 on the surface of the substrate 7 surrounded by the sealing material 10, the ion trapper 3 performs an ion trap to drop the liquid crystal 11 containing few impurity ions, and then face each other in vacuum. The liquid crystal empty cell, which is made by sticking the substrates together or by sticking the periphery of the substrates with a seal, is ion-trapped immediately before the liquid crystal is immersed in the injection port in a vacuum, and the liquid crystal with few impurity ions is injected into the empty cell. It is designed to be directly immersed in the inlet, returned to atmospheric pressure, and vacuum-injected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device having high display quality by preventing impurity ions from being mixed into liquid crystal.

[0002]

2. Description of the Related Art A conventional liquid crystal filling method for a liquid crystal display device will be described below with reference to the drawings.

As a method of filling the liquid crystal between the opposed substrates of the liquid crystal display element, there are largely two methods: a vacuum injection method and a dropping method.
It is divided into two.

FIG. 3 is a sectional view of a liquid crystal injection manufacturing system configuration belonging to the vacuum injection method. As shown in FIG.
Pool with liquid crystal empty cell 8 and liquid crystal 11 with opening 10
13 is put into the closed container 9. After depressurizing the closed container 9 with the vacuum pump 1, the inlet portion of the liquid crystal empty cell 8 is pooled.
Soak in. After that, by returning the pressure in the closed container 9 to the atmospheric pressure, the liquid crystal is injected into the cell due to the pressure difference from the empty cell, and the injection port is sealed and cured with a sealing resin.

As a dropping method, for example, Japanese Patent Laid-Open No. 61-
As disclosed in Japanese Patent No. 55625, after a sealing material is formed by printing on the surface of a substrate, liquid crystal is dropped on the substrate at regular intervals using a dispenser. After that, the opposing substrates are gradually bonded under reduced pressure, and the sealing material is cured.

Further, in recent years, it has been found that the display uniformity of a liquid crystal display element is deteriorated by impurity ions mixed in the liquid crystal, and it is disclosed in JP-A-2-304522 and JP-A-2-304523. In addition, studies have been conducted on putting an ion exchange resin into a pool containing liquid crystal, or injecting liquid crystal using a sponge body containing the ion exchange resin.

[0007]

However, in the above method, the impurity ions from the outside air are mixed in the replenishing liquid crystal, the liquid crystal mixed with the ion exchange resin, or the spongy body containing the liquid crystal with the ion exchange resin. Liquid crystals containing impurity ions are dropped or impurity ions enter from the vicinity of the injection port. In STN type liquid crystals with high steepness, the threshold voltage due to the applied voltage changes due to the influence of the impurity ions, resulting in traces of drops. Threshold unevenness and uneven injection occurred.

The present invention focuses on those problems, and aims to reduce traces of dripping, uneven threshold, and uneven injection by preventing and eliminating impurity ions from the liquid crystal by a simple manufacturing method. .

[0009]

In order to achieve the above object, the present invention performs ion trap immediately before dropping liquid crystal on the surface of a substrate surrounded by a sealing material, and after dropping liquid crystal with few impurity ions. , Either the substrates facing each other in a vacuum are bonded, or the liquid crystal empty cell in which the peripheries of the substrates are bonded with a seal is ion-trapped immediately before the liquid crystal is immersed in the injection port in a vacuum, and the impurity ions A small amount of liquid crystal is directly immersed in the empty cell injection port and returned to atmospheric pressure for vacuum injection.

[0010]

According to the present invention, the impurities are prevented from being mixed from the atmosphere by blocking the liquid crystal from the outside air, and the impurities are trapped by the ion trap just before supplying the liquid crystal to the substrate surface or the liquid crystal empty cell. It is possible to provide a liquid crystal display element having a small number of ions.

[0011]

【Example】

(Embodiment 1) FIG. 1 is a sectional view of a liquid crystal display device manufacturing system configuration according to a first embodiment of the present invention. This belongs to the liquid crystal dropping method, and the liquid crystal container 2 in FIG.
Insert 11 and cover. The liquid crystal 11 flows from the liquid crystal container 2 to the upper part of the ion trapper 3, and the liquid crystal 11 accumulated on the upper part of the ion trapper 3 is ion-trapped by the ion trapper 3 and accumulates on the lower part of the ion trapper 3. Here, after the dispenser 5 is capped, the cock 4 is opened, and the ion trapped liquid crystal 12 is sucked up by the cylinder 6 of the dispenser 5. Close the cock 4 again, remove the cap 14 of the dispenser 5, and use the dispenser 5 to seal the surrounding area.
Glass substrate 7 with transparent electrodes surrounded by 10 and subjected to orientation treatment
After the liquid crystal is dropped onto the substrate, the substrate with the transparent electrodes and the spacers scattered with the same orientation treatment in vacuum and the laminated seal material 10 are cured to prepare a liquid crystal display element.

Next, the liquid crystal display device thus produced was evaluated, and it was found that the liquid crystal display device was of high display quality as compared with the conventional manufacturing method which did not use the ion trapper.

(Embodiment 2) FIG. 2 is a sectional view of a liquid crystal display device manufacturing system configuration according to a second embodiment of the present invention.
This belongs to the liquid crystal vacuum injection method, in which the liquid crystal 11 is put in the liquid crystal container 2 shown in FIG. The liquid crystal 11 flows into the upper part of the ion trapper 3 from the liquid crystal container 2, and the liquid crystal 11 accumulated in the upper part of the ion trapper 3 is ion-trapped by the ion trapper 3 and accumulates in the lower part of the ion trapper 3.
The dispenser 5 and the liquid crystal empty cell 8 are put in a closed container 9, and the inside of this closed container 9 is decompressed by a vacuum pump 1. After the cap 14 is placed on the dispenser 5, the cock 4 is opened, and the cylinder 6 of the dispenser 5 sucks up the ion-trapped liquid crystal 12. The cock 4 is closed again, the cap 14 of the dispenser is removed, the liquid crystal injection port of the liquid crystal empty cell 8 is connected to the tip of the dispenser 5, and the liquid crystal 12 is ion-trapped. After that, the inside of the closed container 9 is returned to atmospheric pressure, and the injection port is sealed and cured to produce a liquid crystal display element.

Next, the liquid crystal display device thus produced was evaluated, and it was found that the liquid crystal display device was of high display quality as compared with the conventional manufacturing method which did not use the ion trapper.

[0015]

As described above, according to the present invention, by blocking the liquid crystal from the outside air and filling the empty cell with the liquid crystal immediately after the ion trap, it is possible to prevent and eliminate the impurity ion mixing from the atmosphere. It is possible to manufacture a liquid crystal display device with less dripping traces, uneven threshold, and uneven injection.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a manufacturing system configuration of a liquid crystal display element according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a liquid crystal display device manufacturing system configuration according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a liquid crystal injection manufacturing system configuration that belongs to a conventional vacuum injection method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum pump, 2 ... Liquid crystal container, 3 ... Ion trapper, 4 ... Cock, 5 ... Dispenser, 6 ... Cylinder, 7 ... Substrate, 8 ... Liquid crystal empty cell, 9 ... Sealed container,
10 ... Sealant, 11 ... Liquid crystal, 12 ... Ion trapped liquid crystal, 13 ... Pool, 14 ... Cap.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoko Nakao 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A liquid crystal in which a liquid crystal is dropped on a surface of a substrate whose periphery is surrounded by a sealing material, and a step of adhering a substrate facing the substrate in vacuum, the liquid crystal having an ion trap on the surface of the substrate. A method for manufacturing a liquid crystal display element, which comprises dropping. 2. A step of injecting the liquid crystal into the empty cell by immersing the inlet of the liquid crystal empty cell in which the periphery of the substrate is pasted with a sealing material in the liquid crystal in vacuum and then returning to the atmospheric pressure, A method for manufacturing a liquid crystal display device, characterized in that an empty cell inlet is immersed in liquid crystal subjected to an ion trap therein.