JP2001005001A - Alignment film for aligning liquid crystal and liquid crystal display element utilizing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antiferroelectric liquid crystal display element while maintaining alignment and low threshold voltage of the liquid crystal and suppressing generation of rubbing trash. SOLUTION: In a liquid crystal display element constructed by enclosing an antiferroelectric liquid crystal 50 between a pair of electrode substrates 10, 20 placed opposite to each other through alignment layers 12, 22, the alignment films 12, 22 contain a polymer selected from the group of imide polymers having structures obtainable from dehydration and ring closure of polyamic acid. The conversion rate to imide of the contained polymer is 40-80%. The film thickness is <=500 Å.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device using an antiferroelectric liquid crystal (antiferroelectric liquid crystal display device) and an alignment film used for aligning liquid crystal molecules in such a liquid crystal display device. About.

[0002]

2. Description of the Related Art In general, an antiferroelectric liquid crystal display device has a pair of electrode substrates having an alignment film formed on one surface of a substrate having a transparent electrode (transparent conductive film), and aligns the pair of electrode substrates with each other. They are arranged so as to face each other with a film, and an antiferroelectric liquid crystal is sealed between both electrode substrates. Here, the antiferroelectric liquid crystal is in a state in which liquid crystal molecules are aligned between the two electrode substrates due to the alignment effect of the alignment film, and a voltage of a certain threshold or more is applied between the two electrode substrates. Thereby, the liquid crystal molecules are driven.

[0003] The orientation of the antiferroelectric liquid crystal is usually exhibited by an orientation film formed by rubbing the surface of a coating made of an organic polymer.
Here, as the organic polymer constituting the coating, resins such as polyimide, polyamide, and polyester are known. In particular, polyimide has heat resistance, affinity with liquid crystal,
Because of its excellent mechanical strength and the like, it is used not only in antiferroelectric liquid crystal display devices but also in many liquid crystal display devices such as devices using nematic liquid crystals.

[0004]

However, since the film composed of the above resin does not have adhesion and toughness to the electrode substrate, if the surface of the film is subjected to a rubbing treatment, depending on the rubbing conditions. In the case of (1), the formed alignment film is peeled off from the electrode substrate, and a large amount of rubbing (rubbing residue) is generated. Such a rubbing residue causes a problem of lowering the orientation of the antiferroelectric liquid crystal and deteriorating the alignment darkness (alignment dark luminance).

[0005] Conventionally, a plurality of resin partitions are provided between a pair of electrode substrates which are arranged to face each other, and both the electrode substrates are set at a predetermined interval while supporting the both electrode substrates by the partition walls. There is. In the case of the configuration having the partition for setting the substrate interval, the partition is bonded to the alignment films of the two electrode substrates to support the two electrode substrates, but the above rubbing residue is formed between the partition and the alignment film. The presence of such an interposition causes a problem that the affinity between the partition and the alignment film is reduced, and the adhesive strength between the alignment film and the partition is reduced.

In the case of an antiferroelectric liquid crystal display device,
The threshold voltage for driving the liquid crystal is, for example, 10 V /
However, from the viewpoint of cost reduction and energy saving of the driver circuit (driving circuit), the thickness of the alignment film is set to, for example, 500 Å or less, preferably 30 Å or less, in order to reduce the driving voltage to 16 V / μm or less.
It is necessary to make it less than 0 angstroms. Then, when the thickness of the alignment film is reduced as described above,
It is easily affected by a hard base substrate (electrode substrate), and the rubbing residue is easily generated.

According to the study by the present inventors, the thickness of the alignment film used in the antiferroelectric liquid crystal display element is increased (for example, 1000 Å or more) to reduce the influence of the underlying substrate and to reduce the rubbing residue. Can be reduced, but as described above, in addition to an increase in the threshold voltage, there are disadvantages in that uneven brightness occurs. This is because as the film thickness increases, it becomes more difficult to control the distance (cell gap) between the electrode substrates.
For example, in an antiferroelectric liquid crystal display device having a narrow cell gap of 1 to 2 μm, the uneven cell gap appears as uneven luminance.

In the case of devices using nematic liquid crystal such as a TN (twisted nematic) liquid crystal device and a TFT (thin film transistor) liquid crystal device, the threshold voltage of the liquid crystal is as low as about 0.3 V / μm. Even when the thickness of the film is set to 700 to 1000 angstroms, the driving voltage is only about 0.6 V / μm, and a driver circuit with a withstand voltage of about 1 V / μm can normally be used. As described above, in the case of a liquid crystal display element using a nematic liquid crystal, since the alignment film having a large thickness can be used, the problem of the rubbing residue is relatively small.

[0009] In view of the above problems, a first object of the present invention is to provide a liquid crystal device having an alignment property and a low threshold voltage.
An object of the present invention is to provide an antiferroelectric liquid crystal display element in which the occurrence of rubbing residue is suppressed, and an alignment film suitable for use in such a liquid crystal display element. Further, a second object of the present invention is to provide an antiferroelectric liquid crystal display device having a partition for setting a distance between substrates by suppressing the occurrence of rubbing residue while achieving the first object. To ensure the adhesion between the film and the alignment film.

[0010]

In order to secure a low threshold voltage, the present inventors have set the thickness of the alignment film to 500 angstroms or less, and the rubbing residue is less likely to occur under this film thickness condition. In order to obtain an alignment film material, experimental studies were conducted on various alignment film materials. The inventions set forth in claims 1 and 2 have been made based on the results of this study.

That is, according to the first aspect of the present invention, the antiferroelectric liquid crystal (50) is disposed between a pair of electrode substrates (10, 20) disposed so as to face each other with the alignment films (12, 22).
In the liquid crystal display element encapsulating, the alignment film contains a polymer selected from the group consisting of an imidized polymer having a structure obtained by dehydration and ring closure of polyamic acid. Imidation rate of the polymer is 40 to
80% and a film thickness of 500 Å or less.

As in the present invention, by setting the thickness of the alignment film in the antiferroelectric liquid crystal display device to 500 Å or less, a low threshold value can be secured. Further, the imidation ratio of the polymer contained in the alignment film is 40%.
By setting the content to 80%, the orientation of the antiferroelectric liquid crystal is favorably maintained, and the occurrence of rubbing residue can be suppressed.

According to experiments by the present inventors, when the imidization ratio is less than 40%, the generation of rubbing residue can be suppressed, but the alignment force of the alignment film itself is weak, and the alignment of the liquid crystal is sufficient. Was not obtained. On the other hand, when the imidation ratio was higher than 80%, a large amount of rubbing residue was generated, and as a result, sufficient orientation of the liquid crystal could not be obtained. As described above, according to the present invention, it is possible to provide an antiferroelectric liquid crystal display element in which the occurrence of rubbing residue is suppressed while ensuring the orientation and low threshold voltage of the liquid crystal.

[0014] According to the second aspect of the present invention, the first aspect is provided.
In the liquid crystal display device described in the above, a pair of electrode substrates (10,
20) Between the two electrode substrates, a resin partition (40) for setting the two electrode substrates at a predetermined interval while supporting the two electrode substrates is provided, and the partition is bonded to the alignment films (12, 22). And According to the present invention, the same function and effect as those of the liquid crystal display element of the first aspect are obtained, and the occurrence of rubbing residue is suppressed, so that the adhesion between the partition and the alignment film can be ensured. That is, the second object can be achieved.

According to a third aspect of the present invention, there is provided an alignment film for liquid crystal alignment which is subjected to a rubbing treatment for aligning an antiferroelectric liquid crystal, the imide having a structure obtained by dehydrating and closing a polyamic acid. A polymer selected from the group consisting of a polymerized polymer, and the imidization ratio of the polymer contained is 40 to 80%, and the film thickness is 500 angstroms or less. When the alignment film of the present invention is used for an antiferroelectric liquid crystal display device, an antiferroelectric liquid crystal display device in which the occurrence of rubbing residue is suppressed while securing the alignment of the liquid crystal and a low threshold voltage is preferable. realizable.

The reference numerals in parentheses of the above means indicate the correspondence with specific means described in the embodiments described later.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 1 shows an antiferroelectric liquid crystal display device (liquid crystal cell) to which the present invention is applied. This liquid crystal display device includes a pair of electrode substrates 10 and 20. These two electrode substrates 10 and 20 are overlapped with each other via an annular seal 30 and a partition 40, and an antiferroelectric liquid crystal 50 is provided between the two electrode substrates 10 and 20.
It is enclosed through.

Here, the electrode substrate 10 is configured such that an alignment film 12 is provided on the inner surface of a seal 30 via a plurality of transparent electrodes 11 on the inner surface of a glass substrate. On the other hand, the electrode substrate 20 has a plurality of transparent electrodes (which constitute a matrix pixel together with the plurality of transparent electrodes) 21 on the inner surface of the glass substrate, and the alignment film 2
2 is provided.

Here, the transparent electrodes 11 and 21 are made of, for example, IT
It is made of O (indium tin oxide) or the like, and is patterned on the inner surface of the glass substrate by vapor deposition, sputtering, or the like. The alignment films 12 and 22 are formed on the transparent electrode 1.
A solution containing a polyamic acid represented by the following general chemical formula 1 is applied to the inner surface of the glass substrate on which the substrates 1 and 21 are formed by spin coating or printing, and then heated to dehydrate and close the polyamic acid. A film made of polyimide cured by polymerization is obtained, and then the polyimide film is formed by rubbing with a resin cloth (nylon cloth or the like) or the like.

[0020]

Embedded image

Here, in the above chemical formula 1, R1 is a tetravalent organic group forming a tetracarboxylic acid or a derivative thereof, R2 is a divalent organic group forming a diamine, and R3 is a hydrogen atom or a carbon atom having 1 carbon atom. And m represents a positive integer, and at least one of R1 and R2 contains an alicyclic structure.

The resulting alignment films 12 and 22 contain a polymer selected from the group consisting of an imidized polymer having a structure obtained by dehydration and ring closure of a polyamic acid. Imidation ratio of 40 to 80
%, And the film thickness is 500 Å or less.

The type of the polyamic acid (polyimide precursor resin) represented by the above formula 1 is not particularly limited, and the reaction and polymerization of tetracarboxylic dianhydride or its derivative and diamine in a polar solvent are carried out. Can be obtained. The tetracarboxylic dianhydride used in the synthesis of the polyimide precursor is not particularly limited, but specific examples thereof include the following.

Aromatic tetracarboxylic acids such as pyromellitic acid, benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid and naphthalenetetracarboxylic acid and their dianhydrides, dicarboxylic acid diacid halides, cyclobutanetetracarboxylic acid, cyclobutane Alicyclic tetracarboxylic acids such as pentanetetracarboxylic acid and cyclohexanetetracarboxylic acid and dianhydrides thereof, dicarboxylic acid diacid halides thereof, and aliphatic tetracarboxylic acids such as butanetetracarboxylic acid and dianhydrides thereof And dicarboxylic acid diacid halides. These tetracarboxylic acids or derivatives thereof may be used alone or in combination of two or more.

Specific examples of the diamine used for synthesizing the polyimide precursor resin represented by the above chemical formula 1 include p-phenylenediamine, 1,4-bis (4-aminophenyl) benzene, 4,4'- Diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-dihydroxy-4,4′-diaminobiphenyl, 3, 3'-dichloro-4,4'-diaminobiphenyl, 3,3'-dicarboxy-4,4'-diaminobiphenyl, 4,4'-bis (4-aminophenoxy) biphenylaminodiphenylmethane, diaminodiphenyl ether, 2, 2-diaminodiphenylpropane, 4,4'-diaminodiphenylsulfone, diaminobenzophenone, 1,3-bis (4-amido Nophenoxy) benzene, 1,4-bis (4-aminophenoxy)
Benzene, 4,4'-di (4-aminophenoxy) diphenylsulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,1,1,3,3,3
-Hexafluoro-2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,5-bis (4′-
Aminophenoxy) pentane, 1,10-bis- (4 ′
Aromatic diamines such as -aminophenoxy) decane, alicyclic diamines such as diaminodicyclohexylmethane, diaminodicyclohexyl ether and diaminodicyclohexane, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane; Examples thereof include aliphatic diamines such as 1,6-diaminohexane, but the present invention is not particularly limited thereto.

The reaction between the tetracarboxylic dianhydride and the diamine to form a polyimide precursor is performed under various known conditions. Generally N-methylpyrrolidone,
A method is employed in which a diamine is added to an organic polar solvent such as N, N-dimethylacetamide or N, N-dimethylformamide, and a tetracarboxylic dianhydride is added to the solution and reacted.

The ratio of tetracarboxylic dianhydride to diamine is preferably from 0.8 to 1.2. As in the ordinary polycondensation reaction, the degree of polymerization of the produced polymer increases as the molar ratio approaches 1. If the degree of polymerization is too small, the strength of the polyimide resin film as the alignment film becomes insufficient. or,
If the degree of polymerization is too large, the workability at the time of forming the polyimide resin film may deteriorate. Therefore, the degree of polymerization of the product (polymer) in this reaction is 0.05 to 5.0 dl / g in terms of reduced viscosity of the polyimide precursor solution (N- at a temperature of 30 ° C.).
The concentration is preferably 0.5 g / dl in methylpyrrolidone.

The reaction temperature of the reaction between the tetracarboxylic dianhydride and the diamine to form a polyimide precursor can be selected from any temperature from -5 ° C to 100 ° C. Further, the polyimide precursor can be dehydrated by heating at 130 to 250 ° C. or chemically imidized using a commonly used imidization catalyst such as pyridine / acetic anhydride to obtain a polyimide.

Further, in the completed alignment films 12 and 22, the imidization ratio needs to be 40 to 80% as described above. When the imidation ratio is lower than 40%,
If the orientation of the liquid crystal is reduced, and if it is higher than 80%, a large amount of rubbing residue is generated or the adhesion between the partition walls 40 and the alignment films 12 and 22 is reduced. This imidization rate can be adjusted by the temperature of the imidation reaction of the polyimide precursor. That is, if the temperature of the imidization reaction is lowered (high), a polyimide having a low (high) imidization rate can be obtained.

Further, the imidation ratio can be adjusted by adjusting the molar ratio of the monomer tetracarboxylic dianhydride to the diamine. That is, as the molar ratio between the tetracarboxylic dianhydride and the diamine as monomers deviates from 1, a polyimide having a lower imidization ratio can be obtained. When the imidation ratio is adjusted by this method, after a certain amount of the polyimide precursor is synthesized in a state where the above molar ratio is close to 1, the molar ratio is shifted by further adding tetracarboxylic dianhydride or diamine in excess. Is more preferred. In the synthesis of the polyimide precursor, if the molar ratio is shifted from the time of the initial mixing, a polyimide precursor having a low degree of polymerization may be obtained.

As described above, each of the electrode substrates 10 and 20 is in a single state (ie, a state in which they are not arranged facing each other).
Transparent electrodes 11, 21 and alignment films 12, 22 on a glass substrate
It is made by forming

The partition 40 is made of a thermosetting resin or the like, and is adhered (closely adhered) to the alignment films 12 and 22 of the electrode substrates 10 and 20. For example, a plurality of barrier ribs 40 are provided in the form of stripes spaced apart from each other, and support both electrode substrates 10 and 20 while supporting both electrode substrates 10 and 20.
Is set to a predetermined cell gap (for example, 1 to 2 μm). The seal 30 is obtained by heating and curing a sealant, and is provided in an annular shape on the outer peripheral side of the alignment films 12 and 22.

The partition wall 40 is formed by applying a resin for forming the partition wall 40 on the alignment film 12 or 22 of one of the electrode substrates 10 and 20 by printing or the like, and curing by heating. Next, one of the electrode substrates 10,
A sealant forming the seal 30 is applied to the surface 20 by printing or the like. At this time, a liquid crystal injection port is formed in a part of the seal 30. Thereafter, as shown in FIG. 1, the two electrode substrates 10 and 20 are superimposed and heated while being pressurized to harden the sealant and secure a predetermined cell gap by supporting the partition walls 40.

Next, the two electrode substrates 10 and 2
During the time 0, the antiferroelectric liquid crystal 50 is heated and liquefied from the liquid crystal injection port, and then injected and filled, and then the liquid crystal injection port is sealed. Thereafter, when the liquid crystal phase is developed by gradually cooling the liquefied antiferroelectric liquid crystal 50, a state in which the liquid crystal molecules are aligned by the alignment films 12 and 22 is realized.
Thus, the antiferroelectric liquid crystal display device shown in FIG. 1 is completed.

By the way, according to the present embodiment, the alignment film 1
By setting the film thickness to 500 angstroms or less (preferably 300 angstroms or less) in the cases 2 and 22, a low threshold value (16 V / μm or less) can be secured. In addition, when the imidation ratio of the polymer contained in the alignment films 12 and 22 is 40 to 80%, the orientation of the antiferroelectric liquid crystal 50 is favorably maintained, and the occurrence of rubbing residue can be suppressed. Further, the partition 40 and the alignment films 12 and 22
And sufficient adhesive strength.

A conventional liquid crystal display device using a nematic liquid crystal uses a polyimide alignment film having an imidization ratio of 40 to 80% in order to suppress flicker (Japanese Patent Application Laid-Open No. 63-172122). In this case, a nematic liquid crystal is used, the thickness of the alignment film is 1000 Å or more, and the cell gap is 5.
Since it is 0 μm or more, even if this conventional configuration is applied to an antiferroelectric liquid crystal display device, the object of the present invention is not achieved.

Next, the present invention will be described more specifically based on the following examples and comparative examples.

[0038]

EXAMPLES (Example 1) SE-41 manufactured by Nissan Chemical Industries, Ltd.
0 (trade name) was used as a polyimide precursor (polyamic acid) solution. This solution was spin-coated on a glass substrate with a transparent electrode at a rotation speed of 1500 rpm.
No repelling or the like was observed at the transparent electrode portion, the glass substrate portion, and the boundary portion between these two portions, and uniform coating could be performed. Then, after heating at 100 ° C. for 5 minutes, a heat curing treatment was performed at 200 ° C. for 1 hour to form a polyimide resin film having a thickness of 400 Å.

The imidation ratio of this polyimide resin film was determined by IR
(Infrared spectroscopy) was 60%.
Here, the average value of the film thickness was measured using a stylus-type film thickness meter. The imidation ratio was determined from the ratio of a peak derived from a benzene ring at 1500 cm ^-1 at which no change occurs due to imidization and a peak derived from an imide group at 1380 cm ^-1 . The imidation ratio of the polyimide fired at 300 ° C. was set to 100%.

This polyimide resin film (coating) was rubbed in a certain direction with a nylon cloth to form an alignment film, and then subjected to ultrasonic cleaning with pure water and isopropanol for 1 minute each. Thus, one electrode substrate was formed. After that, when the amount of rubbing residue was measured with an optical microscope, 1 mm
It was found that 6000 μm ² existed per ² particles. Here, the amount of rubbing residue was obtained by taking a photograph at 400 times with an optical microscope and determining the area of the rubbing residue.

Next, on this one electrode substrate, a partition having a height of 2.0 μm and a width of 20 μm was formed on the alignment film using CT (trade name) manufactured by Fuji Hunt Co., Ltd. as a material of the partition. . Then, a glass substrate with a transparent electrode on which only one electrode substrate and an alignment film are formed (the other electrode substrate)
Were combined with the rubbing direction in the antiparallel direction, a sealant was applied to one of the electrode substrates, and superposed under the conditions of a pressure of 1.0 kg / cm ² , 150 ° C. and 2 hours. Thereafter, an antiferroelectric liquid crystal was injected to produce a liquid crystal cell as an antiferroelectric liquid crystal display element.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was found that the liquid crystal cell had a uniform alignment without any defect. The alignment dark luminance was 0.20%. The threshold voltage was 10 V / μm. In addition, when observed with a microscope, no separation between the partition and the alignment film was observed.

The alignment dark luminance was measured under crossed Nicols (when the light was dark) when the value of the photomultimeter when the transmitted light passing through the liquid crystal cell from the backlight (light source) was maximized was 1000 mV. 2) shows the value of the photomultimeter of the transmitted light in ()) as a relative transmittance. For example, in the case of 2 mV under crossed Nicols, 2 m
V divided by 1000 mV and multiplied by 100, 0.2%
Becomes In addition, the threshold voltage is applied from a dark state (molecular orientation is in an antiferroelectric state) under crossed Nicols, and the light transmittance is 90% of a maximum state (molecular orientation is in a ferroelectric state). Is the voltage value (Vsat90).

Comparative Example 1 A liquid crystal cell was produced in the same manner as in Example 1 except that a heat curing treatment was performed at 300 ° C. for 1 hour instead of 200 ° C. in forming a polyimide resin film. The imidation rate of the formed polyimide resin film was determined by IR
Was 90%. This polyimide resin film was rubbed and washed in the same manner as in Example 1,
When the amount of rubbing residue was measured with an optical microscope, it was 1 m
It was found that 20,000 μm ² existed per m ² .

Further, after the partition walls were formed, they were overlapped with each other, but partial separation between the partition walls and the alignment film was observed. This is considered to be due to the fact that a large amount of rubbing residue was generated as compared with the first embodiment. When the alignment state of the portion where the partition wall of the liquid crystal cell and the alignment film were bonded was observed with a polarizing microscope, the alignment dark luminance was 0.60%.
It was significantly higher than in Example 1. This is considered to be due to the fact that a large amount of rubbing residue was generated, and the alignment of the liquid crystal was deteriorated.

(Example 2) RN-1 manufactured by Nissan Chemical Industries, Ltd.
A liquid crystal cell was produced in the same manner as in Example 1 except that 199 (trade name) was used. The thickness of the formed polyimide resin film is 300 Å, and the imidization ratio is 65.
%Met. This polyimide resin film was rubbed and washed in the same manner as in Example 1, and the amount of rubbing residue was measured with an optical microscope. As a result, it was found that 7000 μm ² existed per 1 mm ² .

Further, after the partition walls were formed, they were superposed, but no separation between the partition walls and the alignment film was observed.
The alignment state of the portion where the partition wall of the liquid crystal cell and the alignment film were adhered was observed with a polarizing microscope.
25%. When the threshold voltage (Vsat90) of this liquid crystal cell was measured, it was 13 V / μm.

Comparative Example 2 A liquid crystal cell was fabricated in the same manner as in Example 1, except that a heat curing treatment was performed at 120 ° C. for 1 hour instead of 200 ° C. in forming a polyimide resin film. The imidation rate of the formed polyimide resin film was determined by IR
Was 20%. This polyimide resin film was rubbed and washed in the same manner as in Example 1,
When the amount of rubbing residue was measured with an optical microscope, it was 1 m
It was found that 6000 μm ² existed per m ² .

Further, when the partition was formed and then superposed, no separation between the partition and the alignment film was observed. Observation with a polarizing microscope of the alignment state of the portion where the partition wall of the liquid crystal cell and the alignment film were adhered revealed that the alignment dark luminance was 0.90%, which was considerably higher than that of Example 1. This is considered to be due to the fact that the orientation of the liquid crystal was deteriorated because the imidation ratio of the orientation film was low.

Comparative Example 3 A liquid crystal cell was manufactured in the same manner as in Example 1 except that the thickness of the alignment film was changed to 1000 Å instead of 400 Å. The imidation ratio of the formed polyimide resin film was 56% when measured by IR. The polyimide resin film was rubbed and washed in the same manner as in Example 1, and the amount of rubbing residue was measured with an optical microscope. As a result, it was found that 5000 μm ² existed per 1 mm ² .

Further, after the partition walls were formed, they were superposed, but no separation between the partition walls and the alignment film was observed.
However, the threshold voltage of this liquid crystal cell (Vsat
90) was 17 V / μm, which was considerably higher than that of Example 1, and was not a practical value as an antiferroelectric liquid crystal display device. This is because the thickness of the alignment film is too large.

As described above, in the first and second embodiments, the antiferroelectric liquid crystal display device in which the occurrence of rubbing residue is suppressed while ensuring the liquid crystal orientation and the low threshold voltage, and the like. Thus, an alignment film suitable for use in a liquid crystal display device could be realized, and furthermore, by suppressing the occurrence of rubbing residues, the adhesion strength between the partition walls and the alignment film could be secured.

In FIG. 1, a partition for setting the substrate interval is provided, but instead of this partition,
It may have a shape such as a spherical shape or a fibrous shape, and may have a structure in which a substrate gap (cell gap) is secured by a spacer used in a normal liquid crystal display element.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a liquid crystal display device according to an embodiment of the present invention.

[Explanation of symbols]

10, 20: electrode substrate, 12, 22: alignment film, 40: partition, 50: antiferroelectric liquid crystal.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kokazu Suzuki 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside DENSO Corporation (72) Inventor Hitoshi Hayashi 1-1-1, Showa-cho, Kariya-shi, Aichi Co., Ltd. F term in DENSO (reference) 2H088 FA02 FA20 JA20 MA01 MA18 2H089 NA07 NA15 NA30 NA31 NA40 NA45 QA04 QA15 RA14 2H090 HB08Y KA15 LA02 MB01 5C094 AA42 BA49 CA19 DA13 EC04 ED20

Claims (3)

[Claims] 1. A pair of electrode substrates (10, 20) arranged so as to face each other with an alignment film (12, 22), and an antiferroelectric liquid crystal (5) sealed between the pair of electrode substrates.
0), wherein the alignment film contains a polymer selected from the group consisting of an imidized polymer having a structure obtained by dehydrating and ring-closing a polyamic acid, A liquid crystal display device characterized in that the imidation ratio of the polymer obtained is 40 to 80% and the film thickness is 500 Å or less. 2. A resin partition (40) is provided between the pair of electrode substrates (10, 20) to support the two electrode substrates and to set the two electrode substrates at a predetermined interval. 2. The liquid crystal display device according to claim 1, wherein said partition walls are bonded to said alignment films (12, 22). 3. An alignment film for liquid crystal alignment, which is rubbed to align an antiferroelectric liquid crystal, and is selected from the group consisting of an imidized polymer having a structure obtained by dehydration and ring closure of a polyamic acid. The imidation ratio of the polymer contained is 40 to 8
0% and a film thickness of 500 angstrom or less.