JPH0519271A - Liquid crystal panel and production thereof - Google Patents

Abstract

PURPOSE:To provide the liquid crystal panel which is free from unequal threshold values and has a uniform display grade and the process for production of this panel. CONSTITUTION:The increased ion components in a liquid crystal pool 3 are removed by installing metallic electrodes 1 which are impressed with a square wave voltage of 64Hz frequency and + or -100 voltage from a square wave generator 2 and consist of plural pieces held at 0.5mm intervals into the liquid crystal pool 3 in the case of a vacuum injection method. The removal effect is further enhanced by adding an ion adsorptive material into the liquid crystal pool 3 and further an ether compd. is added thereto to make uniform display. The ion components in the liquid crystal are decreased in this way and the generation of unequal injection is suppressed. The liquid crystal panel which is uniform in the threshold voltage within the panel lane is thus obtd. This process is advantageous for practicable use as the liquid crystal can be recycled without throwing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel and a manufacturing method thereof, and more particularly to a vacuum injection method for a liquid crystal panel.

[0002]

2. Description of the Related Art In recent years, most liquid crystal panels employ a vacuum injection method.

The liquid crystal which has been repeatedly vacuum-injected is contaminated by various factors, and the resistance value of the liquid crystal material is lowered.

When a liquid crystal having a reduced resistance value is injected into a panel by a vacuum injection method, an ionic component is adsorbed in the vicinity of the injection port due to a chromatographic effect, and the electro-optical threshold voltage of that portion becomes low, resulting in uneven injection. appear.

When the resistance value of the liquid crystal material decreases, when the liquid crystal material is injected into the panel, the threshold voltage is drastically decreased near the injection port.

This deteriorates the display quality as unevenness of the threshold voltage in the panel surface depending on the distance from the injection port.

For this reason, conventionally, in order to avoid the uneven injection, the liquid crystal which is contaminated and has a reduced resistance value is discarded.

[0008]

However, in consideration of the ratio of the liquid crystal material to the panel manufacturing cost in the conventional structure, it is necessary to consider a method of reusing a liquid crystal having a reduced resistance value.

The present invention solves the above-mentioned conventional problems, and provides a liquid crystal panel and a manufacturing method using a liquid crystal in which increased ionic components are removed from the liquid crystal in order to prevent the decrease of the threshold voltage. The purpose is to

[0010]

In order to achieve this object, the liquid crystal panel and the manufacturing method thereof according to the present invention have a structure using liquid crystal subjected to electric field treatment. In addition, an ion-adsorbing substance or an ether compound is supplementarily added.

[0011]

The liquid crystal material has a specific resistance of about 10 ¹² Ωcm or more.

In order to investigate the display uniformity when the ionic component increases in the liquid crystal, a liquid crystal panel in which a liquid crystal having a different specific resistance value is vacuum-injected is prepared, and each liquid crystal panel is kept in a constant temperature environment (25 ° C). , 60Hz, static drive, electro-optical threshold voltage is calculated, triangular wave voltage (0.3Hz,
(± 12 V) is applied, the specific resistance value of the liquid crystal is determined from the ion current component flowing between the panel electrodes, and the relationship between the threshold value and the specific resistance value is shown in FIG.

From FIG. 2, the specific resistance value of 3 × 10 ¹¹ Ω (l
If it is used for vacuum injection as it is, if it is used for vacuum injection as it is, ionic components are concentrated near the injection port due to the chromatographic effect, and the threshold voltage of that part is rapidly lowered.

With the structure of the present invention, it is possible to reduce the ionic components present in the liquid crystal to be vacuum-injected, and to suppress the occurrence of unevenness that causes a decrease in the threshold voltage near the injection port after injection.

The specific resistance value of the injected liquid crystal is 6 × 10 ¹¹ Ωc
By increasing the height to m or more, it is possible to suppress the occurrence of injection unevenness.

Further, by adding an ion-adsorptive substance into the liquid crystal reservoir, the effect of suppressing the uneven injection can be further enhanced.

When the resistance value of the liquid crystal in the panel decreases, the conductivity in the liquid crystal molecule orientation direction increases.

In the ether compound, the ether chain portion becomes a polydentate ligand by the electron-donating oxygen and has a function of incorporating a metal ion or an organic cation.

The addition of this ether compound reduces the mobility of the taken-in ionic component with respect to the electric field,
It is possible to suppress a decrease in threshold voltage.

[0020]

EXAMPLES Specific examples will be described in detail below. (Example 1) A state in which an electric field applying electrode is installed in a liquid crystal reservoir is shown in FIG.

An ionic component (cetyltrimethylammonium chloride, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to adjust the resistance value to 2 × 10 ¹¹ Ω.
Using a liquid crystal (ZLI-2293, manufactured by Merck & Co., Inc.) reduced to cm, the effect of removing an ionic component in the liquid crystal by applying an electric field in the liquid crystal was examined.

First, a liquid crystal having a lowered resistance value is injected into an empty panel provided with a seal resin mixed with a spacer for gap thickness compensation between two glass substrates patterned with electrodes. Injection unevenness with a low threshold voltage occurred.

Next, in the liquid crystal reservoir 3, several metal electrodes 1 held at 0.5 mm intervals were placed.

A rectangular wave voltage having a frequency of 64 Hz and a voltage of ± 100 V was applied from the rectangular wave generator 2 to the metal electrode 1 to generate an electric field.

A liquid crystal whose resistance value was lowered to 2 × 10 ¹¹ Ωcm was passed between the metal electrodes. After 30 minutes, after the ionic component was captured between the metal electrodes, the liquid crystal was taken out and the resistance value was measured.

The resistance value of the liquid crystal was as high as 6 × 10 ¹¹ Ωcm or more, and it was proved that the ion removing effect of the present invention worked sufficiently.

Further, the liquid crystal was injected into the panel, and it was confirmed that there was no uneven injection. (Example 2) In addition to the ion component removing effect of the metal electrode of Example 1, an ion-adsorbing substance (SiO2, Size 0.2) was used.
If 50 wt% of 1 mm or less (manufactured by Offtron Co., Ltd.) is added to the liquid crystal, the ion component removal effect is further enhanced, and the resistance value of the liquid crystal is
It was 10 ¹² Ωcm or more, which was a great effect. (Example 3) In addition to the effect of removing the ionic components of Example 1,

[0028]

[Chemical 2]

An ether compound shown in (5) (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 0.5 wt% liquid crystal, and vacuum injection was performed on an empty panel, whereby a liquid crystal panel having a uniform threshold voltage was formed.

Although the removal of ionic components in the liquid crystal by the vacuum injection method has been described in the embodiments, the present invention also applies to contamination of the liquid crystal dish or contamination of contaminants when the liquid crystal is left unattended. It goes without saying that it can be applied.

[0031]

INDUSTRIAL APPLICABILITY As described above, the present invention can realize an excellent liquid crystal panel free from uneven injection by forming a liquid crystal panel using liquid crystal subjected to electric field treatment.

[Brief description of drawings]

FIG. 1 is a schematic view of a state in which an electric field applying electrode is installed in a liquid crystal reservoir of the present invention.

FIG. 2 is a diagram showing a relationship between a threshold voltage and a specific resistance value.

[Explanation of symbols]

1 metal electrode 2 Square wave generator 3 Liquid crystal reservoir 4 liquid crystal 5 panels

Claims (7)

[Claims] 1. A liquid crystal panel using a liquid crystal subjected to an electric field treatment. 2. The liquid crystal panel according to claim 1, wherein a vacuum injection method is used. 3. A liquid crystal panel according to claim 1, wherein an ion-adsorbing substance is added to the liquid crystal. 4. The liquid crystal panel according to claim 3, wherein silica is used as the ion-adsorbing substance. 5. A liquid crystal panel according to claim 1, wherein an ether compound is added to the liquid crystal. 6. An ether compound as follows: The liquid crystal panel according to claim 5, wherein the liquid crystal panel is used. 7. A method of manufacturing a liquid crystal panel, comprising a step of subjecting liquid crystal to an electric field in a liquid crystal reservoir.