JPH0887017A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE: To obtain a liq. crystal display element having a liq. crystal oriented film with a large and stabilized tilt angle of the liq. crystal molecule to the substrate. CONSTITUTION: A transparent electrode and a liq. crystal oriented film are formed on a couple of substrates at least one of which is transparent, and a liq. crystal is held between the substrates to produce a liq. crystal display element. The coating film of an aq. polycarboxylate soln. shown by the formula (where A is a tri or tetravalent aromatic or aliphatic group, B is a bivalent aromatic or aliphatic group, E is a univalent aromatic or aliphatic group, R1 and R2 are hydrogen atom or 1-3C alkyl, alkoxyl or hydroxyalkyl and can be the same or different, (n) is 1 or 2, and (n) is an integer of 10 to 720) is formed, heated and converted to the polyimide film, and the polyimide film is rubbed to obtain the liq. crystal oriented film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a liquid crystal display device using a polyimide containing a polycarboxylic acid salt as an alignment film.

[0002]

2. Description of the Related Art Various materials have been proposed as alignment film materials for liquid crystal display elements, but polyimide films are used in many fields. It is N-methyl-2-pyrrolidone (NM
P) and dimethylacetamide (DMAC)
A polyimide precursor (polyamic acid) varnish using an organic polar solvent such as is applied on a transparent electrode substrate and the polyimide film thermally imidized is rubbed in a certain direction with a cloth. Then, the liquid crystal composition is put between them, and the liquid crystal composition is put therein and sealed with a sealant to prepare a liquid crystal display element (Japanese Patent Laid-Open No. 59-200216).

By rubbing a polyimide film formed on a substrate, liquid crystal molecules are aligned in the rubbing direction, and at the same time, a liquid crystal tilt alignment angle (abbreviated as tilt angle) of about 1 to 2 ° with respect to the substrate surface. ) Is known to occur. Further, a high tilt angle of 3 to 5 ° is required to secure the viewing angle of the liquid crystal display element. As a means for increasing the tilt angle, vapor deposition of an inorganic film such as silicon oxide, formation of an alignment film having a specific chemical structure (for example, a polyimide film containing a fluorine atom: JP-A-4-294327, long-chain alkylamine A film formed by a reaction of a polyimide precursor: JP-A-64-142099) is known.

[0004]

However, it has not been industrially easy to rub a conventional polyimide film formed on a substrate to form a film having a tilt angle of 4 ° or more with good reproducibility. . The reason for this is considered to be that conventional polyimide is extremely tough, and thus even if the polyimide surface is stretched in one direction by rubbing, the alignment force of the liquid crystal molecules and the regulation force for imparting a large tilt angle are insufficient.

Further, in the conventional polyimide precursor (polyamic acid) varnish, a large amount of organic polar solvent (90% by weight or more of the solid component of the varnish) is discharged into the atmosphere before thermal imidization in the alignment film forming step. Therefore, it was a problem from the working environment.

An object of the present invention is to provide a method of manufacturing a liquid crystal display device having an alignment film which is stable in a high tilt angle and is friendly to the working environment and suitable for mass production.

[0007]

The present inventors have investigated various polyimide precursors and their thermal imidization temperatures, and found that a polycarboxylic acid salt varnish using water as a solvent is a polyimide precursor using a conventional polar solvent. The present inventors have found that the thermal imidization reaction proceeds at a lower temperature than the body varnish and reached the present invention. The gist of the present invention for achieving the above object is as follows.

(1) A pair of substrates, at least one of which is transparent, and a transparent electrode and a liquid crystal alignment film formed on the substrates,
In the method of manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between the pair of substrates, the liquid crystal alignment film has the general formula [1].

[0009]

[Chemical 4]

(However, A is a trivalent or tetravalent aromatic group or aliphatic group, B is a divalent aromatic group or aliphatic group, E
Is a monovalent aromatic group or aliphatic group, R ₁ and R ₂ are hydrogen atoms or alkyl groups having 1 to 3 carbon atoms, alkoxy groups, and hydroxylalkyl groups, which may be different from each other. A method for producing a liquid crystal display device, characterized in that m is 1 or 2 and n is an integer of 10 to 720, and a film of an aqueous solution of a polycarboxylic acid salt is formed, and the polyimide film imidized by heating is rubbed. .

(2) The liquid crystal alignment film has the general formula [2]

[0012]

[Chemical 5]

(Wherein A is a trivalent or tetravalent aromatic group or aliphatic group, B is a divalent aromatic group or aliphatic group, m
Is 1 or 2 and n is an integer of 10 to 720), and a polyamic acid or polyamic acid amide represented by the general formula [3]

[0014]

[Chemical 6]

(Wherein E is a monovalent aromatic group or aliphatic group, R ₁ and R ₂ may be different from each other by a hydrogen atom or an alkyl group having 1 to 3 carbon atoms), and A method for producing a liquid crystal display device, comprising: forming a coating film of the polycarboxylic acid salt aqueous solution and subjecting the polyimide film, which has been imidized by heating, to a rubbing treatment.

The polyimide obtained by heating the above-mentioned polycarboxylic acid salt has a lower thermal imidization temperature and a glass transition temperature lower by 20 to 70 ° C. than a polyimide obtained from a conventional polyimide precursor varnish using a polar solvent. The characteristics are that the density of the polymer is low.

This is because the leaving group and the boiling point of the solvent at the time of thermal imidization are different (DMAC and NMP have a high boiling point of 160 ° C. or higher), and the primary structure is the same as that of the conventional polyimide precursor varnish. However, it is because the higher order structure is different. Further, since the polyimide from the water-soluble polycarboxylic acid salt is relatively soft, the effect of stretching the surface of the polyimide by rubbing is large, and an alignment film which gives a high tilt angle to the liquid crystal with good reproducibility can be obtained.

Further, the low thermal imidization temperature at which the polyimide precursor is converted into polyimide can lower the heating temperature during the production of the liquid crystal display element, and therefore the dye used in the color filter or the TFT (thin film transistor). The effect of heat on the above is small, and it is extremely effective for stabilizing the performance of the display element.

Although polyvinyl alcohol and various celluloses have been proposed as a water-soluble and soft resin, they have a smaller tilt angle than the alignment film of the present invention and are thermally and chemically unstable, so that they can be used as a liquid crystal alignment film. Is not very desirable.

As the polycarboxylic acid salts similar to those used in the present invention, JP-A-4-124614, JP-A-2-247617 and JP-A-6-117 are known.
There is one disclosed in Japanese Patent No. 17 or the like. However, all of these are so-called LB films cumulatively formed on a glass substrate by the LB (Langmuir-Blodgett) method.
It is made into a polyimide by heating it to 0 ° C or higher. Specifically, as shown in JP-A-4-124614, an alignment film obtained by thermally imidizing this varnish with a salt of a long-chain aliphatic group having 12 to 30 carbon atoms and a polyamic acid is:
Due to the influence of the long-chain aliphatic group, the variation range of the tilt angle is large, so that color unevenness is likely to occur on the display screen, which is not preferable in terms of image quality.

The orientation film of the present invention comprises a polycarboxylic acid salt having a repeating unit represented by the above-mentioned general formula [1], or a polycarboxylic acid comprising a polyamic acid and a polyamic acid amide of the general formula [2] and a general formula [ 3) The solution of a polycarboxylic acid salt consisting of an amine compound is applied to a substrate for thermal imidization.

The above aqueous solution of polycarboxylic acid salt is a water-soluble varnish containing 99 to 50% by weight of water with respect to 1 to 50% by weight of polycarboxylic acid salt.

The method for synthesizing the above polycarboxylic acid salt is described in T. Yama
shita, H.Higuchi, K.Horie, and I, Mita, Proceedings
of the International Symposium on "Polymers for M
icro-electronics Science and Technology "(PME'89),
As described in Tokyo, Japan, October 29 to November 2, (1989), there is a method in which an amine compound is ionically bonded to a polyamic acid or a polyamic acid amide. In particular, it can be made water-soluble by forming a salt.

As the amine compound, triethylamine, trimethylamine, tripropylamine, 2-diethylaminoethanol, 2-diethylaminopropyl methacrylate, 2-diethylaminoethyl methacrylate, 2-diethylaminoethyl acrylate, 2-diethylaminopropyl acrylate, 3-diethylamino-1. -Propanol, 1-diethylamino-3-butanone, 2,2-ethanolamine, N-methyldiethanolamine, dimethylaminoethanol, monoethanolamine, N-methylethanolamine and the like,
One or more of these can be used.

Polyamic acid is available from J. Polymer Sci., A-1,3,
As described in 1373 (1965), the method obtained by polycondensing equimolar amounts of tetracarboxylic dianhydride and diamine in a polar solvent is the most industrially excellent. The polar solvent used for polyamic acid synthesis includes NMP, DMAC, dimethylformamide, diglyme, phenol, toluene,
Xylene and the like can be mentioned, and one or more of these can be used.

The polyamic acid amide is most industrially superior to the method obtained by melt polycondensation of equimolar amounts of tricarboxylic acid anhydride and diamine in a polar solvent, as in the synthesis method of polyamic acid. Examples of the polar solvent used in the synthesis include NMP, DMAC, dimethylformamide, diglyme, phenol, toluene, xylene, and the like.
One or more of these can be used.

Tetracarboxylic acid dianhydrides used in the synthesis of polyamic acid include pyromellitic dianhydride, 3,
3 ', 4,4'-biphenyltetracarboxylic dianhydride,
3,3 ", 4,4" -p-terphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic Acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 2,3,5,6-pyridinetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride Anhydride, 4,4'-sulfonyldiphthalic acid dianhydride,
3,3 ", 4,4" -m-terphenyl tetracarboxylic acid dianhydride, bis (3,4-dicarboxyphenyl) ether tetracarboxylic acid dianhydride, bis (3,4-dicarboxyphenyl) sulfone Tetracarboxylic dianhydride, bis
(3,4-dicarboxyphenyl) methanetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propanetetracarboxylic dianhydride, 1,1,1,3,
3,3-hexafluoro-2,2-bis (3,4-dicarboxyphenyl) propanetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) dimethylsilanetetracarboxylic dianhydride, bis ( 3,4-dicarboxyphenyl) diethylsilane tetracarboxylic dianhydride, 2,
3,4,5-pyridinetetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, 3,4-dicarboxy-1,2,
3,4-tetrahydro-1-naphthalene succin tetracarboxylic acid dianhydride may be mentioned. One or more of these can be used.

Examples of the diamine that reacts with the tetracarboxylic dianhydride include o-tolidine, p-phenylenediamine, 2,4-diaminodiphenyl ether and 4,4'-
Diaminidiphenyl ether, 4,4'-diaminidiphenyl sulfone, 4,4'-diaminidiphenylmethane,
4,4'-diaminodiphenyl sulfide, 4,4 "-diaminoterphenyl, 4,4" -diaminodicyclohexylmethane, 1,5-diaminonaphthalene, 4,4'-bis
(p-Aminophenoxy) biphenyl, 4,4'-bis (m
-Aminophenyloxy) diphenyl sulfone, 2,2-bis
(4- (p-aminophenoxy) phenyl) propane, 3,
3'-dimethyl-4,4'-diaminodiphenylmethane,
2,7-diaminofluorene, acetoguanamine, 3,
3'-dimethoxybenzidine, m-phenylenediamine, 2,6-diaminoanthraquinone, 2,6-aminotoluene, 2,5-diaminopyridine, 2,6-diaminopyridine, 2,5-diaminotoluene, 2,3- Diaminopyridine, 3,4-diaminopyridine, 4,4'-diaminobenzophenone, 4,4'-bis (p-aminophenoxy)
Diphenyl sulfone, benzoguanamine, 2,7-diaminonaphthalene, 3,4-diaminotoluene, m-xylenediamine, p-xylenediamine, 4,4'-dithiodianiline, o-phenylenediamine, 4,4'-methylenebis ( 2-Methylcyclohexylamine) tetramethyl-1,4-phenylenediamine, tetraethyl-1,4-
Phenylenediamine, tetrapropyl-1,4-phenylenediamine, trimethyl-1,4-phenylenediamine, triethyl-1,4-phenylenediamine, tripropyl-1,4-phenylenediamine, 3,3 ', 5'-trimethyl -4,4'-diaminobiphenyl, 3,3 ', 5'-
Triethyl-4,4'-diaminobiphenyl, 3,3 ', 5'
-Tripropyl-4,4'-diaminobiphenyl, 1,1,
1,3,3,3-hexafluoro-2,2-bis (4-aminophenyl) propane, diaminosiloxane and the like can be mentioned, and one or more of them can be used.

Tricarboxylic acid anhydrides used for the synthesis of polyamic acid amide include trimellitic anhydride, 3,4,
4'-biphenyl tricarboxylic acid anhydride, 3,4,4'-benzophenone tricarboxylic acid anhydride, 1,5,6-naphthalene tricarboxylic acid dianhydride, 2,6,7-naphthalene tricarboxylic acid dianhydride, 2, 5,6-pyridine tricarboxylic acid dianhydride, 3,9,10-perylene tricarboxylic acid dianhydride, 3,4,4 "-m-terphenyl tricarboxylic acid dianhydride can be mentioned, and at least one of them is used. be able to.

As the diamine compound that reacts with the tricarboxylic acid anhydride, the same diamine compound that reacts with the tetracarboxylic acid dianhydride can be used.

Next, the compounding amount of the amine compound which is indispensable for making it water-soluble is 1.8 to 2.2 mols of the amine compound to 1 mol of the polyamic acid, and 0.1 mol of the amine compound to 1 mol of the polyamic acid amide. It is preferably 9 to 1.2 mol. .

Number average molecular weight (Mn) of polycarboxylic acid
Is an important characteristic that affects the strength of the alignment film. Specifically, gel permeation chromatography (GP
The polystyrene conversion value in C) is 8,000 to 500,000.
0 is preferred. If it is less than 8,000, the mechanical properties are deteriorated and the film may not be formed in some cases. Further, if it exceeds 500,000, the solubility is lowered, which is not preferable.

The alignment film of the present invention can be directly formed on a substrate provided with a transparent electrode, but a further excellent liquid crystal display can be obtained by providing an inorganic insulating film below or above the conductive layer (ITO transparent electrode). An element can be obtained. It is possible to prevent thermal deterioration at the time of curing due to sodium ions in the glass by forming it on the inorganic insulating film rather than directly forming it on the electrode which is the conductive layer. As such an inorganic insulating film, a film of SiO ₂ , Al ₂ O ₃ , or Ti ₂ O is preferable.

Since the polycarboxylic acid salt used in the present invention is water-soluble and has a low thermal imidization temperature, it is a plastic substrate excellent in transparency and impact resistance as a liquid crystal display device substrate, such as an acrylic resin plate or a polycarbonate resin. By using a plate or a polyethylene terephthalate resin plate, the weight of the liquid crystal display element can be reduced.

FIG. 1 is a schematic cross-sectional view in the manufacturing process of an STN liquid crystal display device using an alignment film made of a water-soluble polycarboxylic acid salt varnish of the present invention.

(A) A transparent substrate 2 provided with a transparent electrode 1 and a deflection plate 3 is spin-coated with (b) a polycarboxylic acid salt varnish 4, and (c) is thermally imidized and then rubbed to form an alignment film 5. To do.

Then, (d) two of the above substrates are used as an alignment film 5.
Are arranged so as to face each other and fixed with an organic seal such as an epoxy resin via a spacer 6, and the liquid crystal sealing port 7 to the liquid crystal 8
And (e) the liquid crystal encapsulation port 7 is closed with a sealant 9 such as an epoxy resin to complete the liquid crystal display element. The spacer 6 for holding the distance between the two transparent substrates can be put in the element.

[0038]

The water-soluble polyimide precursor varnish made of a polycarboxylic acid salt has a lower thermal imidization temperature than the conventional polyimide precursor varnish made of a polyamic acid and a polar solvent. Polyimides having different secondary structures are obtained. Further, since the polyimide is soft, the alignment film obtained by rubbing the polyimide has good reproducibility and can easily form a high tilt angle of liquid crystal.

Further, since imidization can be carried out at a relatively low temperature, the influence on TFTs and color filters is small.

[0040]

EXAMPLES The present invention will be described in detail below with reference to examples.

[Example 1] 3,3 ',
4,4'-benzophenone tetracarboxylic dianhydride (B
TDA) and p-xylylenediamine (XYDA) and 1-
A water-soluble polyimide precursor varnish consisting of diethylamino-3-butanone (DEAB) was synthesized to prepare a liquid crystal display device.

(1) Synthesis of Polyamic Acid After replacing a four-necked flask equipped with a thermometer, a nitrogen blowing tube, a calcium chloride tube, and a stirrer with nitrogen, NMP as a reaction solvent was added. Subsequently, diamine was charged and stirred to completely dissolve it, and then tetracarboxylic dianhydride was added. The total amount of the diamine and the tetracarboxylic acid dianhydride is 14% by weight (hereinafter referred to as NV 14%). The NMP is 86% by weight.

The reaction was carried out at room temperature with a stirring speed of 150 rpm for 8 hours. The system generating heat due to the reaction was cooled with water. When the viscosity of the varnish increased during the reaction and the reactant became entangled with the stirring rod, the reaction was terminated at that time. Also,
Even if the reaction was performed for 8 hours or more, the system having a varnish viscosity at 25 ° C. of 50 poise or less continued the reaction.

When the viscosity of the varnish after the reaction is 500 poise or more, the polyamic acid is hydrolyzed by heating at 70 to 80 ° C. to adjust the varnish viscosity to about 100 poise.

The polyamic acid amide was synthesized in the same manner.

(2) Method for preparing water-soluble polyimide precursor varnish: Polyamic acid varnish is poured into water in a mixer to precipitate only polyamic acid, washed thoroughly with water, filtered and dried under reduced pressure to obtain white polyamic acid. It was This polyamic acid 10.0
DEAB 6.2g (0.044mol), water 88.5g
Was placed in a flask and stirred at 2000 rpm for 12 hours at 2000 rpm to be water-solubilized, and then passed through a membrane filter having a pore size of 5 μm to obtain a water-soluble polyimide precursor varnish having an NV of 14%.

The same procedure was performed for the polyamic acid amide varnish.

(3) Method for producing liquid crystal display device The above-mentioned NV14% water-soluble polyimide precursor varnish is
Dilute the varnish to 6% with water and spin coat it on a glass substrate with a transparent electrode at 3000 rpm to give 120-1
Heat treatment was performed in the range of 80 ° C. for 30 minutes to form a uniform polyimide film. This is depressurized (1
After being dried for 3.3 Pa), it was rubbed with a cotton cloth, and two substrates whose rubbing directions were parallel were sealed with an epoxy resin via a spacer of 10 μm to manufacture a liquid crystal display element. After injecting a liquid crystal composition (ZLI-2293: manufactured by Merck & Co., Inc.) into this device, the injection port was sealed with an epoxy resin.

When this liquid crystal display device was rotated in crossed Nicols, clear light and dark were observed, and it was confirmed that the liquid crystal was favorably aligned with respect to the rubbing direction.

(4) Method of measuring tilt angle The tilt angle of the above liquid crystal display device measured by the crystal rotation method was 4.2 °.

The tilt angles of the four devices produced in the same manner were 4.2 ± 0.1 °, and it was confirmed that devices having uniform tilt angles could be obtained.

[Example 2] Water-soluble polyimide precursor varnish consisting of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 4,4 "-diamino-p-terphenyl and DEAB Were synthesized, and four liquid crystal display elements were produced according to Example 1. The tilt angle of these four elements was 4.1 ± 0.1 °.

Example 3 BTDA, bis-4-aminophenoxy-4-phenylsulfone (BATP) and N-
A water-soluble polyimide precursor varnish made of methylethanolamine (MEOA) was synthesized, and four liquid crystal display elements were manufactured according to Example 1. The tilt angle of these four elements was 4.1 ± 0.1 °.

Example 4 A water-soluble polyimide precursor varnish consisting of 4,4′-oxydiphthalic acid dianhydride (OPDA), BATP and MEOA was synthesized, and four liquid crystal display devices were prepared according to Example 1. It was made. The tilt angle of these four elements was 4.2 ± 0.1 °.

[Embodiment 5] OPDA and 2,2-bis [4]
A water-soluble polyimide precursor varnish consisting of-(p-aminophenoxy) phenyl] hexafluoropropane (6FAP) and 2-diethylaminoethanol (DEAE) was synthesized, and four liquid crystal display devices were produced according to Example 1. . The tilt angle of these four elements was 4.1 ± 0.1 °.

Example 6 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic acid dianhydride (DSDA) and 6F
A water-soluble polyimide precursor varnish consisting of AP and DEAE was synthesized, and four liquid crystal display elements were produced according to Example 1. The tilt angle of these four elements was 4.4 ± 0.1 °.

Example 7 A water-soluble polyimide precursor varnish consisting of DSDA, 4,4′-diaminodiphenyl ether (DDE) and DEAE was synthesized, and four liquid crystal display devices were produced according to Example 1. The tilt angle of these four elements was 4.1 ± 0.1 °.

Example 8 Trimellitic anhydride (TM
A water-soluble polyimide precursor varnish consisting of DA), DDE, and DEAB was synthesized, and four liquid crystal display elements were manufactured according to Example 1. The tilt angle of these four elements is 4.3
It was ± 0.1 °.

[Example 9] A water-soluble polyimide precursor varnish consisting of TMDA, DDE and 3-diethylamino-3-propanol (DEAP) was synthesized, and four liquid crystal display devices were produced according to Example 1. The tilt angle of these four elements was 4.3 ± 0.1 °.

Example 10 A water-soluble polyimide precursor varnish consisting of biphenyltetracarboxylic acid anhydride, DDE and DEAP was synthesized, and four liquid crystal display elements were produced according to Example 1. The tilt angle of these four elements is 4.
It was 2 ± 0.1 °.

[Comparative Example 1] In the same manner as in Example 1, using the conventional polyamic acid varnish (BTDA + XYDA / NMP) using NMP as a solvent in the thermal imidization temperature measurement, four liquid crystal displays were prepared. A device was produced. The tilt angle of these four elements is 1.6 ± 0.8 °, and it can be seen that the tilt angle is smaller and the homogeneity is inferior as compared with the above-mentioned respective examples.

[Comparative Example 2] A polyamic acid varnish consisting of OPDA, DDE and NMP was used in accordance with Example 1 to 4
Individual liquid crystal display elements were produced. The tilt angle of these four elements was 1.1 ± 0.6 °.

Comparative Example 3 TMDA, 6FAP and NMP
According to Example 1, four liquid crystal display elements were produced using the polyamic acid varnish consisting of The tilt angle of these four elements was 1.9 ± 0.9 °.

[0064]

The tilt angle of the liquid crystal display device of the present invention using a polyimide film obtained from a water-soluble polycarboxylic acid salt as an alignment film can be highly reliable and can be obtained. In addition, the polar solvent is not discharged during the manufacturing process, which is excellent from the working environment.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a manufacturing process of an STN liquid crystal display element of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transparent electrode, 2 ... Transparent substrate, 3 ... Deflection plate, 4 ... Polycarboxylate varnish, 5 ... Alignment film, 6 ... Spacer, 7 ... Liquid crystal encapsulation port, 8 ... Liquid crystal, 9 ... Sealant.

Front Page Continuation (72) Inventor Hisao Yokokura 1-7-1 Omika-cho, Hitachi City, Hitachi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Kishiro Iwasaki 7-1-1 Omika-cho, Hitachi City, Ibaraki Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Hiroshi Sasaki 7-1, 1-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Akio Takahashi Seven, Mika-machi, Hitachi City, Ibaraki Prefecture 1-1-1, Hitachi, Ltd. Hitachi Research Laboratory

Claims (5)

[Claims] 1. A pair of substrates, at least one of which is transparent,
In a method of manufacturing a liquid crystal display device in which a transparent electrode and a liquid crystal alignment film are formed on the substrate and a liquid crystal is sandwiched between the pair of substrates, the liquid crystal alignment film is represented by the general formula [1] (However, A is a trivalent or tetravalent aromatic group or aliphatic group, B is a divalent aromatic group or aliphatic group, E is a monovalent aromatic group or aliphatic group, R ₁ , R ₂ Is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, an alkoxy group, or a hydroxylalkyl group, which may be different from each other, m is 1 or 2, and n is an integer of 10 to 720). A method for producing a liquid crystal display device, which comprises forming a film of a salt solution and rubbing an imidized polyimide film by heating. 2. A pair of substrates, at least one of which is transparent,
In a method of manufacturing a liquid crystal display device in which a transparent electrode and a liquid crystal alignment film are formed on the substrate and a liquid crystal is sandwiched between the pair of substrates, the liquid crystal alignment film is represented by the general formula [2] (However, A is a trivalent or tetravalent aromatic group or aliphatic group, B is a divalent aromatic group or aliphatic group, m is 1 or 2, and n is an integer of 10 to 720) An acid or polyamic acid amide and a compound represented by the general formula [3] (However, E is a monovalent aromatic group or an aliphatic group, R ₁ , R ₂
Is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms and may be different from each other) forms a film of an aqueous solution of a polycarboxylic acid salt with an amine compound and is heated to rub the imidized polyimide film. A method of manufacturing a liquid crystal display device, which is characterized by the following. 3. The general formula [3] for 1 mol of the polyamic acid or polyamic acid amide represented by the general formula [2].
When the amine compound represented by is m = 1, it is 0.9 to 1.2.
The method for producing a liquid crystal display device according to claim 2, wherein an aqueous solution of polycarboxylic acid salt is used in which 1.9 to 2.2 moles are mixed when m and m = 2. 4. The method for producing a liquid crystal display device according to claim 1, wherein the polycarboxylic acid salt aqueous solution comprises 1 to 50% by weight of the polycarboxylic acid salt and 99 to 50% by weight of water. 5. The method for manufacturing a liquid crystal display device according to claim 1, wherein the substrate is a plastic substrate.