JPH05341296A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display element which does not increase electric current consumption even in a high-temp. environment and has excellent reliability by using an imide polymer for a sealing material. CONSTITUTION:The sealing material is formed of the imide polymer and further, this imide polymer is formed of a linear polymer. The imide polymer is obtd. by bringing a carboxylic acid compd. and an amine compd. into reaction. Chlorine compds. are not used as starting raw material for many of these raw materials and further, the raw materials alone are stabler than a glycidyl compd. which is the raw material of an epoxy resin and, therefore, the refining by washing, recrystallization/filtration, etc., is executable until high purity is attained. Further, the imide polymer has excellent chemical stability and hardly generates the deterioration by corrosion of liquid crystals and the deterioration by humidity even in the high-temp. environment. The liquid crystal display element having the excellent reliability is obtd. by using the imide polymer for the sealing material in the above-mentioned reasons.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device using an imide polymer as a sealing material.

[0002]

2. Description of the Related Art Conventionally, low melting point glass and epoxy resin have been known as sealing materials for liquid crystal display elements.
Although low-melting glass has excellent reliability of the seal part after the liquid crystal display element is manufactured, high temperature treatment of 300 to 400 ° C. is required to cure the seal material, and a fine ITO transparent electrode circuit or liquid crystal alignment film, Further, depending on the type of the liquid crystal display element, it may be unusable in most cases because the color filter and the semiconductor element formed on the substrate are greatly damaged, and are not generally used. Currently used sealing materials are epoxy resin-based, and their curing temperature is less than 200 ° C, which is excellent in workability. However, problems have arisen with the widespread use environment of liquid crystal display devices such as vehicle mounted displays and portable televisions. That is, there is a problem that ionic impurities and the like in the seal material are eluted into the liquid crystal in a high temperature environment, increasing the current consumption. Since the epoxy resin uses epichlorohydrin, which is a chlorine compound as a raw material, it is difficult to remove chlorine ions. Therefore, sodium ions, potassium ions and the like which are counter ions are easily mixed, and this problem is difficult to solve.

[0003]

DISCLOSURE OF THE INVENTION The present invention improves the drawbacks of the liquid crystal display device using the conventional sealing material as described above, and makes it possible to prevent an increase in the amount of current consumption over time even in a high temperature environment. It provides an element.

[0004]

The present invention is a liquid crystal display device in which the sealing material is an imide-based polymer, and further the liquid crystal display device in which the imide-based polymer is a linear polymer.

[0005]

The imide polymer used in the present invention can be obtained by reacting a carboxylic acid compound and an amine compound. Many of these raw materials do not use a chlorine compound as a starting raw material, and, by themselves, are more stable than the glycidyl compound, which is a raw material of the epoxy resin, and thus are highly purified by cleaning, recrystallization / filtration, etc. Can be done up to. In this way, because of the high degree of purification possible from raw materials, imide-based polymers can
It is possible to obtain a high-purity sodium ion of 1 ppm or less.

Further, the imide polymer is excellent in chemical stability, and is resistant to corrosion deterioration due to liquid crystal and deterioration due to humidity even in a high temperature environment. For these reasons, the use of the imide polymer as the sealing material makes it possible to obtain a highly reliable liquid crystal display element.

The imide-based polymer is roughly classified into a thermosetting polymer represented by bismaleimide and a linear polymer. In the present invention, either one can be used, but linear imide polymers are more preferable because many of them can be cured at a low temperature.

Examples of preferable linear imide polymers include polyimide, polyamide imide, polyether imide, polyester imide, and poly silicone imide, but are not particularly limited thereto.

The sealing material used in the present invention may contain spacer polymer beads, silica beads, or glass fibers. Further, in order to improve the workability at the time of forming the seal material, silica fine particles or the like may be contained.

[0010]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 A 3-neck separable flask equipped with a thermometer, a stirrer, a raw material charging port, and a dry nitrogen gas inlet tube was charged with 23.39 of 1,3-bis (3-aminophenoxy) benzene.
g (0.08 mol) is dissolved in 193 g of N-methyl-2-pyrrolidone. Under dry nitrogen gas inflow, 24.82 g (0.08 mol) of 3,3 ', 4,4'-oxydiphthalic acid dianhydride was added all at once, and the temperature was 20 ° C.
While maintaining the above, stirring was continued for 5 hours to obtain a polyamic acid varnish.

To this system, 58 g of toluene was added, the dry nitrogen gas introduction pipe was removed, and a Dean Starch reflux cooling pipe was attached instead to raise the temperature of the system. Heating was continued while removing water generated by imidization from the system by azeotropic distillation with toluene, and the reaction was terminated 5 hours after the imidization proceeded at 140 to 150 ° C. and no more water was produced. The resulting polyimide varnish was added dropwise to 30 liters of methanol with stirring for 1 hour to precipitate the polymer, and the solid content was collected by filtration, and then dried at 120 ° C in a dryer at 8 ° C.
Allowed to dry for hours.

75 parts by weight of the polyimide thus obtained,
25 parts by weight of high-purity silica powder with a particle size of 1 μm or less, N-methyl-
After stirring 200 parts by weight of 2-pyrrolidone, the mixture was kneaded with a three-roll mill to obtain a uniform paste-like sealing material.

3.0 parts by weight of high-purity silica beads having a particle size of 8.5 μm were added to and mixed with this sealing material, and the periphery of the 10 mm × 10 mm ITO electrode washed with ultrapure water and the electrode on the glass substrate with the alignment film were mixed. A 20 mm × 20 mm portion was screen-printed so as to be surrounded by a line width of 1 mm, except for the portion that becomes the liquid crystal inlet.
Subsequently, after predrying in a clean oven at 120 ° C for 30 minutes, the glass substrates similar to the above are made to face each other and bonded,
The substrate was fixed with clips so as not to shift, and cured in a clean oven at 170 ° C for 120 minutes. Further, liquid crystal (ZLI-1132 manufactured by Merck & Co., Inc.) was injected, and the injection port was sealed to produce a liquid crystal display element.

When the liquid crystal display device was driven by a rectangular wave of ± 3 V, the current consumption was measured and found to be 0.48 μA.
Furthermore, when observing an increase in current consumption when left in an environment of 85 ° C, it was 0.50 μA even after 1000 hours,
Little change was seen.

(Example 2) 1,3-bis (3-aminophenoxy) benzene 22.98 was placed in a four-neck separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube.
g (0.0786 mol) and silicone diamine represented by formula (1)

[Chemical 1] 17.10 g (0.0224 mol) of N-methyl-2-pyrrolidone 166 g
Dissolve in. Under an inflow of dry nitrogen gas, 31.02 g (0.1 mol) of 3,3 ′, 4,4′-oxydiphthalic acid dianhydride was charged at once, and stirring was continued for 5 hours while maintaining the temperature at 20 ° C. Subsequently, 63 g of toluene was added to this system, and a polysilicone imide was obtained in the same manner as in Example 1 below.

Polysilicon imide thus obtained
75 parts by weight, 25 parts by weight of high-purity silica powder having a particle size of 1 μm or less, and 200 parts by weight of N-methyl-2-pyrrolidone were stirred and then kneaded with a three-roll mill to obtain a uniform paste-like sealing material. Using this sealing material, a liquid crystal display element was manufactured in the same manner as in Example 1 below.

When the liquid crystal display device was driven by a rectangular wave of ± 3 V, the current consumption was measured and found to be 0.47 μA.
Furthermore, when we observed an increase in current consumption when left in an environment of 85 ° C, it was 0.48 μA even after 1000 hours,
Little change was seen.

(Comparative Example) 50 parts by weight of bis (4-glycidyloxyphenyl) methane and 50 parts by weight of 2,2-bis (4-glycidyloxyphenyl) propane were mixed, and the particle size was further adjusted to 1 μm.
30 parts by weight of the following high-purity silica powder and methyl cellosolve 10
After adding a part by weight and stirring, the mixture was kneaded with a three-roll mill, and adipic acid hydrazide was further mixed as a curing agent to obtain an epoxy sealing material. Using this sealing material, a liquid crystal display element was manufactured in the same manner as in Example 1 below.

When the liquid crystal display device was driven with a rectangular wave of ± 3 V, the current consumption was measured and found to be 0.48 μA. 8
Observing an increase in current consumption when left in an environment of 5 ° C, the current increased after 10 hours, reached 1.1 μA after 50 hours, and increased to 2.0 μA or more after 100 hours. .

[0021]

The liquid crystal display device of the present invention is a liquid crystal display device which is excellent in reliability without causing an increase in current consumption even in a high temperature environment.

Claims (2)

[Claims] 1. A liquid crystal display device in which the sealing material is an imide polymer. 2. The liquid crystal display device according to claim 1, wherein the imide polymer is a linear polymer.