JP3513888B2 - Liquid crystal display device and method of manufacturing the same - Google Patents

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 a manufacturing method thereof, and more particularly to a liquid crystal display device having an improved alignment control method and a manufacturing method thereof.

[0002]

2. Description of the Related Art At present, as an alignment film of a twisted nematic (TN) type liquid crystal display device, a super twisted nematic (STN) type liquid crystal display device and an active matrix (AM) type liquid crystal display device which are industrially manufactured, A unidirectionally rubbed polyimide thin film coated on a substrate is widely used.

However, there is a drawback that the pretilt angle of the polyimide alignment film produced by this method is greatly affected by the alignment film production conditions, film thickness, rubbing cloth, rubbing strength, and the type of liquid crystal material. It was This tendency becomes remarkable when an attempt is made to obtain a high pretilt angle of 4 degrees or more, which has been a serious problem in manufacturing an STN type liquid crystal display device which requires a particularly high pretilt angle.

As a means for solving this, Phillip J. Bos et al., 1993.
FY SID Digest '
93) on page 877, a composition comprising a photopolymerizable material and a liquid crystal material is enclosed between two electrodes that have been subjected to an alignment treatment,
A method for producing a liquid crystal display device having the same characteristics as a liquid crystal display device having a high pretilt angle has been reported by polymerizing and curing the photopolymerizable material by irradiating ultraviolet rays while applying a voltage to the composition. There is.

However, the photopolymerizable material used in the above manufacturing method has poor compatibility with the liquid crystal material, and is formed during the phase separation process between the liquid crystal material and the photopolymerizable material, which is induced upon irradiation with ultraviolet rays. The polymer network thus formed disturbs the alignment of the liquid crystal material, and there is a drawback that a uniform alignment state cannot be obtained.

[0006]

The problem to be solved by the present invention is to provide a liquid crystal display device having a liquid crystal material in which the alignment state is uniform and having the same characteristics as a liquid crystal display device having a high pretilt angle, and to manufacture the same. To provide a method.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to solve the above-mentioned problems, and as a result, have reached the present invention.

In other words, in order to solve the above-mentioned problems, the present invention has two transparent substrates having at least one transparent electrode having an alignment treatment, and the orientation directions on the two substrates are 180 to 270. A liquid crystal / polymer composite between the substrates in the range of 0 °, and the liquid crystal / polymer composite contains a nematic liquid crystal and a polymer of a chiral substance and a diacrylate compound having a liquid crystalline skeleton, The liquid crystal / polymer composite contains liquid crystal molecules aligned along the interface between the polymer and liquid crystal, and liquid crystal molecules tilted in the range of 2 to 50 ° with respect to the substrate surface. A liquid crystal display element is provided.

The liquid crystal display element of the present invention can be manufactured, for example, according to the following manufacturing method. That is, at least one of the two substrates having the transparent electrode subjected to the alignment treatment is transparent, and the alignment direction on the two substrates is 180.
A liquid crystal / polymer composite forming material containing a nematic liquid crystal and a chiral substance and a diacrylate compound having a liquid crystalline skeleton is sandwiched between substrates in the range of ˜270 ° to orient the nematic liquid crystal and the chiral substance. After that, while applying a voltage to the liquid crystal / polymer composite forming material, the liquid crystal / polymer composite is irradiated with an actinic ray to polymerize a diacrylate compound having a liquid crystalline skeleton.

The nematic liquid crystal used in the present invention may contain a substance other than the nematic liquid crystal as long as it is generally recognized as a liquid crystal material in this technical field, and it has a positive dielectric anisotropy. Those are preferable.

The nematic liquid crystal used in the present invention is preferably a compounded composition composed of one or more compounds selected from the liquid crystal compound group shown below, and has characteristics of the liquid crystal material, that is, an isotropic liquid and a liquid crystal. Phase transition temperature, melting point, viscosity, Δε
For the purpose of improving (dielectric anisotropy) and Δn (refractive index anisotropy), they can be appropriately selected and blended for use.

Examples of the liquid crystal compound include 4-substituted benzoic acid phenyl ester, 4-substituted cyclohexanecarboxylic acid 4'-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid 4'-substituted biphenyl ester,
4- (4-Substituted cyclohexanecarbonyloxy) benzoic acid 4-substituted phenyl ester, 4- (4-substituted cyclohexyl) benzoic acid phenyl ester, 4- (4-substituted cyclohexyl) benzoic acid 4′-substituted cyclohexyl ester, 4- Substituted 4′-substituted biphenyl, 4-substituted 4 ′
-Substituted cyclohexane, 4-substituted 4 "-substituted terphenyl, 4-substituted biphenyl 4'-substituted cyclohexane, 2
Examples thereof include-(4-substituted phenyl) -5-substituted pyridine. Particularly preferred among these compounds are compounds having a cyano group at least at one end of the molecule.

The chiral substance used in the present invention includes:
For example, cholesterol pelargonate having a cholesteryl group as an optically active group, cholesterol stearate, and “C having a 2-methylbutyl group as an optically active group”
B-15 "," C-15 "(above, manufactured by BHD (BDH))," S1082 "(manufactured by Merck),
"CM-19", "CM-20", "CM" (manufactured by Chisso), "S811" (manufactured by Merck) having 1-methylheptyl group as an optically active group, "CM-21", "CM"
-22 "(above, manufactured by Chisso Co.).

The diacrylate compound having a liquid crystalline skeleton used in the present invention does not necessarily exhibit liquid crystallinity as a simple substance,

[0015]

[Chemical 10]

(Where

[0017]

[Chemical 11]

Each independently,

[0019]

[Chemical 12]

And each of X and Y independently represents a single bond, --CH ₂ CH _2- , --OCO--, --COO--, --CH.
₂ O—, —OCH ₂ — or —C≡C—, D or E each independently represents a single bond, an ester bond, an ether bond, Z represents a hydrogen atom or a methyl group, and m or n represents Each independently represent an integer of 0 to 6, and p is 0 or 1
Represents an integer of 0, q represents an integer of 0, 1 or 2, and the cyclohexane ring represents a trans-cyclohexane ring. )
The compound represented by can be used.

In the above general formula, the diacrylate compounds having a liquid crystal skeleton may have the same Z or different Z. Furthermore, the compounds shown below are preferred.

[0022]

[Chemical 13]

(In the above formula, Z represents a hydrogen atom or a methyl group, and the cyclohexane ring represents a trans-cyclohexane ring.)

[0024]

[Chemical 14]

[0025]

[Chemical 15]

[0026]

[Chemical 16]

(In the above formula, Z represents a hydrogen atom or a methyl group, m or n each independently represents 2, 4 or 6, and the cyclohexane ring represents a trans-cyclohexane ring.)

[0028]

[Chemical 17]

[0029]

[Chemical 18]

(In the above formula, Z represents a hydrogen atom or a methyl group, m or n each independently represents 1, 3 or 5, and the cyclohexane ring represents a trans-cyclohexane ring.)

[0031]

[Chemical 19]

(In the above formula, Z represents a hydrogen atom or a methyl group, m represents 2, 4 or 6, n represents 1, 3 or 5, and the cyclohexane ring represents a trans-cyclohexane ring.)

[0033]

[Chemical 20]

(In the above formula, Z represents a hydrogen atom or a methyl group, m represents 1, 3 or 5, n represents 2, 4 or 6, and the cyclohexane ring represents a trans-cyclohexane ring.)

[0035]

[Chemical 21]

(In the above formula, Z represents a hydrogen atom or a methyl group, m represents 2, 4 or 6, n represents 1, 3 or 5, and the cyclohexane ring represents a trans-cyclohexane ring.)

[0037]

[Chemical formula 22]

(In the above formula, Z represents a hydrogen atom or a methyl group, m represents 1, 3 or 5, n represents 2, 4 or 6, and the cyclohexane ring represents a trans-cyclohexane ring.)

[0039]

[Chemical formula 23]

(In the above formula, Z represents a hydrogen atom or a methyl group, and the cyclohexane ring represents a trans-cyclohexane ring.)

[0041]

[Chemical formula 24]

(In the above formula, Z represents a hydrogen atom or a methyl group, m or n each independently represents 1, 3 or 5, and the cyclohexane ring represents a trans-cyclohexane ring.)

[0043]

[Chemical 25]

(In the above formula, Z represents a hydrogen atom or a methyl group, m or n each independently represents 2, 4 or 6, and the cyclohexane ring represents a trans-cyclohexane ring.)

[0045]

[Chemical formula 26]

(In the above formula, Z represents a hydrogen atom or a methyl group, m represents 1, 3 or 5, n represents 2, 4 or 6, and the cyclohexane ring represents a trans-cyclohexane ring.)

[0047]

[Chemical 27]

(In the above formula, Z represents a hydrogen atom or a methyl group, m represents 2, 4 or 6, n represents 1, 3 or 5, and the cyclohexane ring represents a trans-cyclohexane ring.) Among the diacrylates of, general formulas (a) to (c)

[0049]

[Chemical 28]

(In the formula, Z ¹ and Z ² are each independently
Represents a hydrogen atom or a methyl group. ) Are novel compounds, and the present invention also provides these compounds.

The diacrylate having a liquid crystalline skeleton used in the present invention is preferably dissolved in the nematic liquid crystal and the chiral substance at a ratio of 1 to 20% by weight, and more preferably at a ratio of 1 to 3% by weight. It is preferably dissolved.

Further, in order to accelerate polymerization and curing of a diacrylate compound having a liquid crystalline skeleton by irradiation of ultraviolet rays, a polymer of a nematic liquid crystal or chiral substance and a diacrylate compound having a liquid crystalline skeleton is used to initiate photopolymerization. The agent may be dissolved, and the concentration thereof is preferably 1 to 20% by weight, more preferably 2 to 10% by weight, based on the diacrylate compound having a liquid crystal skeleton.

Examples of the above-mentioned polymerization initiator include 2-hydroxy-2-methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Geigy). "Irgacure 184"), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1
-One (“Darocur 1116” manufactured by Merck), benzyl dimethyl ketal (“Irgacure 651” manufactured by Ciba Geigy), 2-methyl-1- [4- (methylthio)
Phenyl] -2-morpholinopropanone-1 (“Irgacure 907” manufactured by Ciba Geigy), 2,4-diethylthioxanthone (“Kayacure DET manufactured by Nippon Kayaku Co., Ltd.”)
X ") and ethyl p-dimethylaminobenzoate (" Kayacure EPA "manufactured by Nippon Kayaku Co., Ltd.), isopropylthioxanthone (" Cantacure ITX "manufactured by Ward Prekinsop) and ethyl p-dimethylaminobenzoate. A mixture etc. are mentioned.

The substrate used in the present invention may be a rigid material such as glass or metal, or a flexible material such as a plastic film. At least one of them must be transparent so that the liquid crystal / polymer composite sandwiched between the two can be seen from the outside world. However, complete transparency is not essential.

The distance between the two electrodes is preferably 2 to 20 μm, particularly preferably 4 to 8 μm. As a means for applying a voltage between the electrodes, a driving means used in a normal liquid crystal display element can be used, and the applied voltage is preferably an AC voltage of 0.5 to 50V, more preferably 0.5 to 10V.

The alignment treatment applied to the substrate used in the present invention is, for example, a rubbing treatment of an organic thin film of polyimide or the like coated on a transparent electrode, or oblique vapor deposition of SiO, for those having ordinary knowledge in this technical field. Known alignment treatment methods can be mentioned.

[0057]

EXAMPLES The present invention will now be described more specifically by showing examples of the present invention. However, the invention is not limited to these examples. In the following synthesis examples, examples, preparation examples and comparative examples, "%" represents "% by weight".

Example 1 Synthesis of diacrylate (1)

[0059]

[Chemical 29]

(Step 1) Synthesis of Intermediate (1)

[0061]

[Chemical 30]

10.0 g of 2- (hydroxyphenyl) ethyl alcohol, 20.75 g of acrylic acid, and p-
Toluenesulfonic acid (3 g) was dissolved in benzene (150 ml), and the mixture was heated under reflux for 10 hours while separating generated water using a Dean-Stark water separator. After cooling to room temperature,
The reaction solution was washed with water and benzene was distilled off under reduced pressure to obtain 12.6 g of a crude product. This was subjected to silica gel column chromatography (ethyl acetate: n-hexane = 1: 1, Rf =
0.53) and 10.3 g of intermediate (1)
Got

(Second Step) Synthesis of Intermediate (2)

[0064]

[Chemical 31]

5.0 g of 4-hydroxymethylbenzoic acid,
Acrylic acid 7.4 g, p-toluenesulfonic acid 3.8
g and hydroquinone (1.1 g) were dissolved in 100 ml of benzene, and the mixture was heated under reflux for 5 hours while separating water produced using a Dean-Stark water separator. After cooling to room temperature, the reaction solution was washed with water and benzene was distilled off under reduced pressure to obtain 10.4 g of a crude product. This was subjected to silica gel column chromatography (ethyl acetate: n-hexane = 1: 1, Rf = 0.
45) and purified by recrystallization from a mixed solvent of 50 ml of n-hexane and 18 ml of ethyl acetate to obtain 2.7 g of intermediate (2).

(Third stage) 1.0 g of a synthetic intermediate (2) of diacrylate (1), 0.01 g of 2,6-di-tert-butylphenol, 4 ml of thionyl chloride and 0.01 g of dimethylformamide were added. After stirring at room temperature for 10 minutes, unreacted thionyl chloride was distilled off under reduced pressure and 15 ml of tetrahydrofuran was added. A solution prepared by dissolving 0.93 g of intermediate (1) and 1.06 g of triethylamine in 20 ml of tetrahydrafuran was added dropwise to this solution over 5 minutes, and the mixture was further stirred for 4 hours. The reaction solution was extracted with methylene chloride, the organic layer was washed with water, and the organic solvent was distilled off under reduced pressure to obtain 1.7 g of a crude product. This was subjected to silica gel column chromatography (ethyl acetate: n-hexane = 1: 5, Rf = 0.21) and ethanol 10
Purification by recrystallization from ml gave 0.7 g of diacrylate (1). The melting point was measured and found to be 79 ° C.

(Synthesis Example) Synthesis of diacrylate (2)

[0068]

[Chemical 32]

2-hydroxyethyl acrylate 2.8
g, triethylamine 4.9 g tetrahydrofuran 1
After dissolving in 5 ml, 10 ml of a THF solution in which 3.0 g of 4,4'-biphenyldicarbonyl chloride was dissolved was added dropwise to this solution over 5 minutes. After stirring for 3 hours, the mixture was extracted with methylene chloride, the organic layer was washed with water, and the organic solvent was distilled off under reduced pressure to obtain 4.1 g of a crude product. This was purified by recrystallization from 20 ml of ethanol to obtain 2.2 g of diacrylate (2). When the melting point was measured,
It was 72 ° C.

Example 2 Synthesis of diacrylate (3)

[0071]

[Chemical 33]

To 0.5 g of trans-1,4-cyclohexanedicarboxylic acid, 4 ml of thionyl chloride and 0.01 g of dimethylformamide were added, and the mixture was stirred at room temperature for 30 minutes, and then unreacted thionyl chloride was distilled off under reduced pressure. 10 ml of tetrahydrofuran was added. In this solution, the intermediate (1)
A solution prepared by dissolving 1.11 g and 1.40 g of triethylamine in 20 ml of tetrahydrofuran was added dropwise over 5 minutes, and the mixture was further stirred for 4 hours. The reaction solution was extracted with methylene chloride, the organic layer was washed with water, and then the organic solvent was distilled off under reduced pressure to obtain 1.6 g of a crude product. This is ethanol 1
Purification by recrystallization from 8 ml gave 1.0 g of diacrylate (3). This compound has a monotropic nematic liquid crystal phase, transitions from an isotropic liquid phase to a nematic phase at 126 ° C., and a crystalline phase to an isotropic liquid phase at 132 ° C.
It was transferred at.

Example 3 Synthesis of diacrylate (4)

[0074]

[Chemical 34]

(First Step) Synthesis of Intermediate (3)

[0076]

[Chemical 35]

To 20.0 g of 4-hydroxybenzoic acid, 60 ml of ethanol and 55 ml of sodium hydroxide dissolved in water were added and stirred. Potassium iodide 1.
8 g and 14.4 g of 6-chloro-1-hexanol were added, and the mixture was heated under reflux for 20 hours. After heating under reflux, add 20 to the reaction solution.
After adding 0 ml of water, the reaction solution was neutralized with a dilute aqueous hydrochloric acid solution. The precipitate formed in the reaction solution was collected by filtration,
This was recrystallized from 55 ml of ethanol to give 19.9 g.
The intermediate (3) of was obtained.

(Second Step) Synthesis of Intermediate (4)

[0079]

[Chemical 36]

Intermediate (3) 16.0 g, acrylic acid 1
5.0 g, p-toluenesulfonic acid 8.0 g, and hydroquinone 0.5 g were dissolved in benzene 210 ml, and the mixture was heated under reflux for 12 hours while separating generated water using a Dean-Stark water separator. After cooling to room temperature, the reaction solution was washed with water and benzene was distilled off under reduced pressure to obtain 34.6 g of a crude product. Add 150 ml of hexane and 50 ml of dichloromethane.
Purified by recrystallization from 1 ml of mixed solvent (13.6 g)
The intermediate (4) of was obtained.

(Third step) 0.75 g of synthetic intermediate (4) of diacrylate (4), 0.01 g of 1,2-di-tert-butylphenol, 2.2 ml of thionyl chloride, and 0.01 g of dimethylformamide. In addition, after stirring at room temperature for 10 minutes, unreacted thionyl chloride was distilled off under reduced pressure, and 10 ml of toluene was added. This solution is used as an intermediate (1)
It was added dropwise to a 20 ml toluene solution in which 0.49 g and 0.8 g of pyridine were dissolved over 5 minutes. After stirring for another 2 hours, the organic layer was washed with water, and the organic layer was evaporated under reduced pressure to give 1.10.
g of crude product was obtained. This was subjected to silica gel column chromatography (ethyl acetate: n-hexane = 1: 2, Rf
= 0.47) and recrystallized from 5 ml of ethanol to obtain 0.22 g of diacrylate (4).
The melting point was measured and found to be 42 ° C.

Preparation Example Nematic liquid crystal composition (A)
Preparation of

[0083]

[Chemical 37]

A nematic liquid crystal composition (A) consisting of was prepared. The physical properties of this liquid crystal composition were as follows. Transition temperature 68.7 ℃ (N-I) n e = 1.702 n o = 1.513 Δn = 0.189 Δε = 7.17 or less, in Reference Examples 1-4, crystalline framework for use in the present invention The tilted orientation angle of the liquid crystal display device was measured when the diacrylate compound having the formula was used. In addition, in Reference Example 5, the tilt orientation angle of the liquid crystal display device when a diacrylate compound having no liquid crystalline skeleton was used was measured.
The measured results are shown in Table 1.

Reference Example 1 A nematic liquid crystal composition containing 97% of the liquid crystal composition (A) and 3% of the diacrylate (1) synthesized in Synthesis Example 1 was prepared, and the nematic-isotropic liquid transition temperature was measured. The temperature was 62.4 ° C. This nematic liquid crystal composition contains 8 parts by weight of diacrylate (1).
% Of a polymerization initiator “Irgacure 651” (benzyl dimethyl ketal manufactured by Ciba-Geigy) was added to prepare a mixture, which was then injected into an anti-parallel cell having a cell gap of 10 μm on which a polyimide alignment film was formed. Then, it was confirmed by polarization microscope observation that this mixture was oriented in the rubbing direction in the cell.

While applying a sine wave having a frequency of 1 KHz and a voltage of 1 V to the above cell, ultraviolet rays were irradiated at a temperature of 28 ° C. to polymerize the diacrylate compound to prepare a liquid crystal display device. Polymerization was passed under a metal halide lamp (120 W / cm ² ) twice at a speed of 4 m / min, 1500 mJ / cm ²
Was performed by irradiating with energy corresponding to.

As a result of observing the obtained liquid crystal display device with a polarization microscope, it was confirmed that the alignment of liquid crystal molecules was uniform and was not disturbed even after irradiation with ultraviolet rays. The tilt orientation angle of this liquid crystal display device was measured by applying the crystal rotation method used for measuring the pretilt angle. Three
As a result of measuring at three points at intervals of mm, the values were 2.8 °, 2.9 °, and 2.9 °, respectively. From this result, it is clear that the alignment of the liquid crystal in the liquid crystal display element is not disturbed.

Reference Example 2 A liquid crystal display device was obtained in the same manner as in Reference Example 1 except that the diacrylate (2) was used in Reference Example 1. The nematic-isotropic liquid transition temperature of the nematic liquid crystal composition of 97% liquid crystal composition (A) and 3% diacrylate (2) was 62.4 ° C.

As a result of observing this liquid crystal display element with a polarization microscope, it was confirmed that the alignment of liquid crystal molecules was uniform and was not disturbed even after irradiation with ultraviolet rays. The value of the tilt orientation angle measured at 3 points at intervals of 3 mm is 3.1 °,
The angles were 3.2 ° and 3.2 °.

Reference Example 3 A liquid crystal display device was obtained in the same manner as in Reference Example 1 except that the diacrylate (3) was used in Reference Example 1. Nematic liquid crystal composition (A) 97% and diacrylate (3) 3% nematic liquid crystal composition-
The isotropic liquid transition temperature was 66.7 ° C.

As a result of observing this liquid crystal display element with a polarization microscope, it was confirmed that the alignment of liquid crystal molecules was uniform and was not disturbed even after irradiation with ultraviolet rays. The value of the tilt orientation angle measured at 3 points at intervals of 3 mm is 3.1 °,
It was 3.1 ° and 3.1 °.

Reference Example 4 In Reference Example 1, JP-A-6
Liquid crystalline diacrylate (5) described in JP-A-3-64029.

[0093]

[Chemical 38]

In the same manner as in Reference Example 1, except that
A liquid crystal display device was obtained. The nematic-isotropic liquid transition temperature of the nematic liquid crystal composition of 97% liquid crystal composition (A) and 3% diacrylate (4) was 69.0 ° C. Moreover, as a result of observing this liquid crystal display element with a polarization microscope, it was confirmed that the alignment of the liquid crystal molecules was uniform and was not disturbed even after irradiation with ultraviolet rays. The values of the tilted orientation angle measured at 3 points at intervals of 3 mm are 5.0 °, 5.0 °,
It was 5.0 °.

Reference Example 5 Diacrylate (6) having no liquid crystal skeleton as diacrylate in Reference Example 1

[0096]

[Chemical Formula 39]

A liquid crystal display device was obtained in the same manner as in Reference Example 1 except that was used. The nematic-isotropic liquid transition temperature of the nematic liquid crystal composition of 97% liquid crystal composition (A) and 3% diacrylate (5) was 59.3 ° C. As a result of observing this liquid crystal display element with a polarization microscope, it was confirmed that there were places where the alignment of liquid crystal molecules was disturbed. Also, 3 mm
The values of the tilt orientation angles measured at three positions at intervals of 1.2 °, 5.0 ° and 4.4 °, respectively.

[0098]

[Table 1]

As is clear from the tilted orientation angles of the liquid crystal display device shown in Table 1, the diacrylate compounds having a liquid crystal skeleton (diacrylates (1) to (5)) do not have a liquid crystal skeleton. Compared to the diacrylate compound (diacrylate (6)), the alignment uniformity of liquid crystal molecules is excellent.

Example 4 2.4% of cholesterol pelargonate was added to the liquid crystal composition (A) to prepare a chiral mixture, and the pitch was measured and found to be 8.53 μm. A nematic liquid crystal composition containing 98% of this chiral mixture and 2% of diacrylate (1) synthesized in Synthesis Example 1 was prepared. To this nematic liquid crystal composition, a polymerization initiator “Irgacure 651” (benzyl dimethyl ketal manufactured by Ciba-Geigy) in an amount corresponding to 8% of the amount of diacrylate (1) was added to prepare a mixture, and two sheets of the mixture were prepared. The film was injected into a TN cell having a cell gap of 4.9 μm on which a polyimide alignment film having an alignment direction of 270 ° was formed on a substrate. While applying a sine wave with a frequency of 1 KHz and a voltage of 8 V to this cell,
Ultraviolet rays were irradiated at a temperature of 28 ° C. to polymerize the diacrylate compound to prepare a liquid crystal display device. The polymerization was carried out by passing it under a metal halide lamp (120 W / cm ² ) twice at a speed of 4 m / min and irradiating it with energy corresponding to 1500 mJ / cm ² . When the obtained liquid crystal display element was placed between two polarizing plates which were orthogonal to each other and a voltage was applied to it, it was confirmed to operate. Further, generation of stripe domains was not confirmed even when a voltage was applied to the obtained liquid crystal display element under observation with a polarizing microscope.

Comparative Example 1 2.4% of cholesterol pelargonate was added to the liquid crystal composition (A) to prepare a chiral mixture, and the pitch was measured and found to be 8.53 μm. This mixture was injected into a TN cell having a polyimide alignment film and a cell gap of 4.9 μm to obtain a liquid crystal display device. When the obtained liquid crystal display element was placed between two polarizing plates which were orthogonal to each other and a voltage was applied to it, it was confirmed to operate. However, when a voltage was applied to the obtained liquid crystal display device under observation with a polarizing microscope, stripe domains were generated.

Example 5 A liquid crystal display device was obtained in the same manner as in Example 4, except that the diacrylate (4) synthesized in Example 3 was used as the diacrylate in Example 4. It was confirmed that the obtained liquid crystal display element was placed between two polarizing plates which were orthogonal to each other, and a voltage was applied thereto to operate. Further, when a voltage was applied to the obtained liquid crystal display element under observation with a polarizing microscope, generation of stripe domains was not confirmed.

From the above results, it is apparent that the liquid crystal display element of the present invention does not generate stripe domains and has excellent alignment uniformity as in the liquid crystal display element having a high pretilt angle.

[0104]

The liquid crystal display device of the present invention is a liquid crystal display device having a uniform liquid crystal alignment state and the same characteristics as a liquid crystal display device having a high pretilt angle.
It can be applied to STN type display elements.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-3-140921 (JP, A) JP-A-3-21904 (JP, A) JP-A-63-64029 (JP, A) JP-A-6- 289374 (JP, A) European patent application publication 331233 (EP, A 1) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02F 1/1337 G02F 1/133 500 G02F 1/13 500 G02F 1 / 137 C09K 19/38

Claims (5)

(57) [Claims] 1. A transparent substrate having at least one of which has a transparent electrode subjected to an alignment treatment, wherein the two substrates are transparent, and the alignment direction on the two substrates is in the range of 180 to 270 °.
A liquid crystal / polymer composite, wherein the liquid crystal / polymer composite is
A nematic liquid crystal and a polymer of a chiral substance and a diacrylate compound having a liquid crystalline skeleton are contained.
The polymer composite contains liquid crystal molecules aligned along the interface between the polymer and the liquid crystal, and is 2 to 50 relative to the substrate surface.
Containing liquid crystal molecules are inclined in DEG, the liquid crystal bone
The diacrylate compound having a case is represented by the general formula (a) : (In the formula, Z ¹ and Z ² are each independently a hydrogen atom or
Or represents a methyl group. ), The general formula (b) : (In the formula, Z ¹ and Z ² are each independently a hydrogen atom or
Or represents a methyl group. ) Or the general formula (c) : (In the formula, Z ¹ and Z ² are each independently a hydrogen atom or
Or represents a methyl group. ) A liquid crystal display device comprising a compound represented by 2. A diacrylate compound having a liquid crystal skeleton is added to a nematic liquid crystal and a chiral substance in an amount of 1 to 20.
The liquid crystal display device according to claim 1, wherein the liquid crystal display device is present in the range of weight%. 3. At least one transparent substrate having an alignment-treated transparent electrode, wherein the two substrates have an orientation direction in the range of 180 to 270 ° between the two substrates.
A liquid crystal / polymer composite forming material containing a nematic liquid crystal and a chiral substance and a diacrylate compound having a liquid crystalline skeleton is sandwiched, and the nematic liquid crystal and the chiral substance are aligned, and then the liquid crystal / polymer composite is formed. The method for producing a liquid crystal display device according to claim 1, wherein the material is irradiated with an actinic ray while applying a voltage to polymerize the diacrylate compound having a liquid crystalline skeleton. 4. The method of manufacturing a liquid crystal display device according to claim 3, wherein the applied voltage used is in the range of 0.5 to 50V. 5. A diacrylate compound having a liquid crystal skeleton is added to a nematic liquid crystal and a chiral substance in an amount of 1 to 20.
It exists in the range of weight%, The manufacturing method of the liquid crystal display element of Claim 4 characterized by the above-mentioned.