JPH03200932A - Liquid crystal element and its production and application of liquid crystal element - Google Patents

Abstract

PURPOSE:To improve liquid crystal characteristics by approximately paralleling and reversing the orientation treating directions of the orientation control films respectively provided on the inside surfaces of two sheets of substrates and incorporating a specific carboxylic acid ester compd. into a liquid crystal material. CONSTITUTION:The orientation control films are provided respectively on the inside surfaces of two sheets of the substrates and the orientation treating directions of two sheets of these orientation control films are approximately parallel and reverse. In addition, the liquid crystal material contains the carboxylate compd. expressed by formula I. In the formula I, R<1> denotes one kind of the group selected from 6 to 18C alkyl group, 6 to 18C alkoxy group, 6 to 18C halogenated alkyl group; (m) denotes 1 to 10 integer; C* denotes an asymmetric carbon atom. The liquid crystal characteristics are improved; for example, the contrast ratio of the liquid crystal element is increased, the operating temp. is lowered to about room temp., the width of the operating temp. is widened, the switching speed is increased, and electric power consumption is lessened.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a liquid crystal element, a method for manufacturing the same, and uses of the liquid crystal element.

Conventionally, CRT devices have been most widely used as display devices for office automation equipment and the like.

In the field of OAIQ devices having such display devices, there has recently been an increasing demand for smaller and lighter equipment, or for larger and thinner display devices. For this reason, various new display devices have been developed in place of the conventionally used CRT devices in response to various uses or demands. Examples of such display devices include liquid crystal displays, plasma displays, LED displays,
There are EL displays, ECD displays, etc.

Among these display devices, liquid crystal displays basically produce light by applying an electrical signal to a switching element containing a liquid crystal compound and changing the state of the liquid crystal compound in the switching element in response to this electrical signal. This is a device that controls transparency to make electrical signals visible on the screen. And, such a liquid crystal device is the above-mentioned OA.
It has already been put to practical use not only as a liquid crystal display for devices, but also as a display device for digital watches and portable game consoles, for example. In addition, they have recently begun to be used as display devices for moving images such as small televisions.

Display devices using such liquid crystal compounds are TN (
(twisted nematic) mode. This TN mode is a display method that utilizes the dielectric anisotropy of molecules in the nematic phase of liquid crystal.
The display device is driven by energy proportional to the square of the electric field applied from the outside (fωE2).

However, when this method is adopted, in order to change the displayed image, it is necessary to change the position of the molecules of the liquid crystal compound in the element, which increases the driving time and changes the position of the molecules of the liquid crystal compound. There is a problem in that the voltage required for this purpose, that is, the power consumption increases. Furthermore, in such a switching element,
Because the switching threshold characteristics are not very good,
If a switching operation is performed by changing the molecular position at high speed, leakage voltage may be applied to the non-display image area, and the contrast of the display device may be significantly reduced.

As described above, the conventional TN mode display system has aspects that cannot be said to be suitable for a moving image display device such as a large screen display device or a small digital television.

Furthermore, display devices are being used that utilize the 5TN (super twisted nematic) mode, which has improved switching threshold characteristics and the like in the TN mode as described above. Utilizing such an STN mode improves the switching threshold characteristics, thereby improving the contrast of the display device.

However, this method is no different from the TN mode in that it utilizes dielectric anisotropy, and therefore has a long switching time, so it is not suitable for large screen display devices or video display devices such as small digital televisions. When used, it exhibits the same tendency as a display device using TN mode.

On the other hand, in 1975, R.B. Meyer et al. discovered that the organic compound they synthesized exhibited ferroelectricity. Furthermore, in 1980, they suggested the possibility of using an element in which a ferroelectric liquid crystal compound as described above filled in a small gap cell as an optical switching element, that is, a display device.

A switching element using a ferroelectric liquid crystal compound as described above can function as a switching element simply by changing the orientation direction of the molecules of the liquid crystal compound, unlike a switching element using TN mode or STN mode. , the switching time is greatly reduced. Furthermore, the spontaneous polarization (Ps) of ferroelectric liquid crystal compounds
Since the value of PsXE given by and the electric field strength (E) is the effective energy strength for changing the orientation direction of the molecules of the liquid crystal compound, power consumption is also extremely small. Since such ferroelectric liquid crystal compounds have two stable states, or bistability, depending on the direction of the applied electric field, their switching threshold characteristics are also very good, making them useful as display devices for moving images. Particularly suitable for use.

By the way, when using such a ferroelectric liquid crystal compound in an optical switching element, etc., the ferroelectric liquid crystal compound has certain characteristics, such as an operating temperature range near or below room temperature, a wide operating temperature range, and a switching Many characteristics are required, such as high speed and a switching threshold voltage within an appropriate range. Among these, the operating temperature range is a particularly important characteristic when putting ferroelectric liquid crystal compounds into practical use.

However, in the ferroelectric liquid crystal compounds known so far, for example, R, B, Meyer, et al.
.

al, , [Journal de Physique (J,
dePhys, ) Volume 36, page L-69, 1975]
As described in the paper by Masaaki Taguchi and Takamasa Harada [Proceedings of the 11th Liquid Crystal Conference, p. 168, 1985], ferroelectric liquid crystal compounds generally have a high operating temperature and operate near room temperature. However, a practically satisfactory ferroelectric liquid crystal compound has not been obtained due to insufficient operating temperature range and other properties.

Object of the Invention The present invention provides a liquid crystal element with excellent liquid crystal properties such as particularly excellent orientation of liquid crystal material, high contrast, wide operating temperature range, high switching speed, and low power consumption, and a method for manufacturing the same. The purpose is to provide applications for liquid crystal devices.

41 In the liquid crystal element according to the present invention, a gap between cells formed by two opposing substrates is filled with a liquid crystal substance, and each of the inner surfaces of the two substrates is provided with an alignment control film. are provided, and the orientation processing methods for these two orientation control films are approximately parallel and in opposite directions.

In other words, on each surface of the substrate facing the liquid crystal material, a liquid crystal material that is oriented by the regulating force of one alignment control film and a liquid crystal material that is oriented by the regulating force of the other alignment control film, Two alignment control films are provided so that they are substantially parallel and in substantially opposite directions.

Furthermore, the liquid crystal substance is characterized in that it contains a carboxylic acid ester compound represented by the following formula [A].

...[A] However, in formula [A], R1 is selected from the group consisting of an alkyl group having 6 to 18 carbon atoms, an alkoxy group having 6 to 18 carbon atoms, and a halogenated alkyl group having 6 to 18 carbon atoms. m is an integer from 1 to 10, and the C umbrella represents an asymmetric carbon atom.

The method for manufacturing a liquid crystal device according to the present invention is such that when manufacturing a liquid crystal device in which a liquid crystal material is filled in a cell gap formed by two opposing substrates, each substrate has an alignment layer on the inner surface of the two substrates. A cell is formed by providing a control film so that the orientation treatment directions thereof are substantially parallel and in opposite directions, and a liquid crystal material containing a carboxylic acid ester compound represented by the above formula [A] is placed in the gap between the cells. After heating the liquid crystal material contained in the cell to a temperature higher than that at which it exhibits an isotropic phase,
It is characterized in that the liquid crystal material is cooled to a temperature below the temperature at which it exhibits liquid crystal at a cooling rate of below .degree. C./min.

Further, a liquid crystal display device, an electro-optical display device, and an optical switching element according to the present invention are characterized by using the above-mentioned liquid crystal element.

The liquid crystal composition used in the present invention has particularly excellent orientation of liquid crystal substance molecules, so a liquid crystal element formed by using such a liquid crystal composition has a high contrast ratio and a low operating temperature. It has excellent liquid crystal characteristics, such as being close to room temperature, wide operating temperature range, high switching speed, and low power consumption.

By manufacturing the liquid crystal element of the present invention by the method described above, the orientation of the liquid crystal substance is particularly improved, so the contrast ratio is high, the operating temperature is below room temperature, and the operating temperature range is wide. A liquid crystal element with excellent liquid crystal properties such as high switching speed and low power consumption can be obtained.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a liquid crystal element according to the present invention, a method for manufacturing the same, and uses of the liquid crystal element will be specifically described.

First, a liquid crystal element according to the present invention will be explained.

FIG. 1 shows an example of a cross section of a liquid crystal element according to the present invention.

As shown in FIG. 1, the liquid crystal element according to the present invention basically consists of two transparent substrates (hereinafter also referred to as substrates) la and l.
The cell 2 is made up of a gap 3 formed by the two substrates 1a and lb, and a liquid crystal substance 4 filled in the gap 3 of this cell.

At least one of the substrates 1a, lb must be transparent, and the substrate is usually made of glass or transparent plastic (for example, polycarbonate, a polymer of 4-methyl-1-pentene, or ethylene and other alumina). - amorphous polyolefin which is a copolymer with olefin), etc. are used.

On the surfaces of such substrates 1a, lb facing the liquid crystal material (inner surfaces of the two substrates), electrodes 5a, 5b are usually provided.
is provided. In the present invention, a transparent electrode substrate in which a transparent electrode is integrally formed on the substrate as described above can also be used as the substrate.

In the liquid crystal element of the present invention, alignment controls 1iL6a and 6b are provided on the surface of the substrate as described above that is in contact with the liquid crystal substance.

In the present invention, this alignment control film is arranged on the surface of each substrate facing or in contact with the liquid crystal substance in the alignment treatment direction of the alignment control film, that is, the liquid crystal that is aligned by these two alignment control films. The substrates are provided on two substrates in a positional relationship such that the orientation directions of the substances are substantially parallel and opposite.

In the present invention, a cell provided with two alignment control films is used, and the alignment control films 6a and 6b are
has the effect of orienting the liquid crystal material as described above.

Therefore, when the alignment control film is subjected to an alignment treatment (rubbing) so that the alignment direction of the liquid crystal compound is reversed, the initial alignment of the liquid crystal substance injected into the cell Z is improved.
A liquid crystal element with a high contrast ratio can be obtained.

These alignment control films may be formed from an organic material or an inorganic material.

Examples of alignment control films made of organic materials include:
Polyvinyl alcohol, polyimide, polyamideimide, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, polyamide,
Examples include alignment control films made of resins such as polystyrene, siloxane polyimide, cellulose resin, melamine resin, urea resin, acrylic resin, or conductive polymer. Furthermore, the orientation control film may be, for example, a cyclized rubber photoresist, a phenol novolak photoresist, or polymethyl methacrylate, an epoxidized
．． It may also be a cured product of an electron beam photoresist such as 4-polybutadiene. Further, the alignment control film may be formed from an inorganic material, and in this case, examples of materials for forming the inorganic alignment control film include Sin, 5in2, Ge
OlAl 20. ,Y2O2,ZrO,,MgF,
CeFs can be mentioned.

In the present invention, polyimide membranes are particularly preferably used among these resins. Here, polyimide is a resin whose main component is polyimide.

The polyimide may be any polymer compound having an imide bond, and it is particularly preferable to use a resin or a resin precursor that can be easily formed into a film shape.

Examples of the above commercially available polyimides include:
Ubilex-R5 manufactured by Ube Industries ■ Sunever 130 manufactured by Nissan Chemical Industries ■ JIA-28 manufactured by Japan Synthetic Rubber ■, AL
1251, Kerimide 601 manufactured by Nippon Polyimide ■, HL-1100 manufactured by Hitachi Chemical ■, PIQ-5400SLX
-1400, LQ-1800, etc. However, the polyimide used in the present invention is not limited to these commercially available polyimides. Furthermore, the polyimide used in the present invention may contain other resins such as polyamide within a range that does not impair its properties, and bonds other than imide bonds within the molecule within a range that does not impair the properties of the polyimide. It may have.

Such an alignment control film can be produced by applying a resin such as the one described above to the surface of the substrate in contact with the liquid crystal using a spin cord method, by applying heat treatment after such application, by pasting a resin film, Various methods can be employed depending on the material used, such as applying a photosensitive resin and curing it by irradiating energy rays, or depositing an inorganic material.

The thickness of such an alignment control film is usually o, oos ~ 0.2
5 μm, preferably in the range of 0.01-0.15 μl.

The control film used in the present invention is preferably subjected to alignment treatment. Here, the alignment treatment refers to a treatment for aligning liquid crystal molecules in a predetermined direction. For example, when polyimide is used, the polyimide is unidirectionally oriented with fibers or something made of fibers, such as cloth. This polyimide can be subjected to an orientation treatment by a rubbing method such as rubbing.

In the cell 2 used in the present invention, a gap 3 filled with a liquid crystal substance is formed by two substrates 1a and lb on which alignment control films 6a and 6b are formed as described above.

Such a gap 3 can be formed, for example, by arranging the substrates 1a and 1b with spacers 7 interposed therebetween. By arranging the spacer 7 in this manner, it is possible to secure the gap 3 for filling the liquid crystal material, and it is also possible to prevent leakage of the liquid crystal material. Note that the gap 3 can be formed using a spacer that forms a side wall as described above, and can also be formed by blending particles (internal spacer) having a predetermined particle size into the liquid crystal material. .

The width of the gap formed in this way is usually 1.5 to 7
μm1 is preferably within the range of 1.8 to 5 μm.

In addition, in the liquid crystal element of the present invention, for example, a photoconductive film,
Various thin films such as a light blocking film and a light reflecting film may be provided on the alignment control film on the side opposite to the substrate. ing.

The liquid crystal substance used in the present invention contains a liquid crystal compound represented by the following formula [A]. In particular, in the present invention, although the liquid crystal compound represented by formula [A] can be used alone, the liquid crystal composition must contain at least one or more liquid crystal compounds represented by formula [A]. is preferred.

... [A] However, in formula [A], R1 is selected from the group consisting of an alkyl group having 6 to 18 carbon atoms, an alkoxy group having 6 to 18 carbon atoms, and a halogenated alkyl group having 6 to 18 carbon atoms. It is a type of group that can be used. Moreover, m is an integer from 1 to 10,
Cm represents an asymmetric carbon atom.

In the above formula [A1, when R1 is an alkyl group having 6 to 18 carbon atoms, such alkyl group may be in any form of linear, branched, or alicyclic, but R1 The molecules of carboxylic acid esters, in which is a linear alkyl group, exhibit excellent liquid crystallinity because they have a rigid structure with straight molecules. Specific examples of such linear alkyl groups include hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, hexadecyl and octadecyl groups. I can do it.

Further, when R1 is a halogenated alkyl group having 6 to 18 carbon atoms, examples of the halogenated alkyl group include at least a portion of the hydrogen atoms of the alkyl group as described above.
Mention may be made of groups substituted with halogen atoms such as F, CQ, Br and I.

Further, when R1 is an alkoxy group having 6 to 18 carbon atoms, examples of such an alkoxy group include an alkoxy group having an alkyl group as described above. Specific examples of such alkoxy groups include:
Mention may be made of hexoxy, heptoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tetradecyloxy, heptadecyloxy, hexadecyloxy and octadecyloxy groups.

Among the above compounds, compounds in which R1 is an alkoxy group exhibit particularly excellent liquid crystallinity.

In the above formula [A], m is an integer of 1-10. Therefore, in the above formula [A]: -(CH2)2-CH.

C.F.

Groups where m is 3, m is 4, etc. include m is 1, m is 5, m is 6, m is 2, etc. Among these, m is 4 Compounds in which m is 6 are useful as liquid crystal compounds, and in particular, compounds having the following groups in which m is 5 are most useful as liquid crystal compounds.

-C-(CR2) s CHa C.F.

That is, in the carboxylic acid ester compound of the present invention, a trifluoromethyl group and an alkyl group having m of 1 to 10 are bonded to the asymmetric carbon atom CI.

The above asymmetric carbon atom is bonded to the phenylene group through an ester bond.

In formula [A], the above phenylene group is O-
Mention may be made of phenylene, m-phenylene and p-phenylene. In particular, the carboxylic acid ester compound preferably has a linear molecule itself, and therefore, the phenylene group is preferably a p-phenylene group.

This phenylene group is bonded to another phenylene group (second phenylene group) via an ester bond. Examples of the second phenylene group include an 0-phenylene group, an m-phenylene group, and a p-phenylene group, similar to the above-mentioned second phenylene group. In particular, it is preferable that the molecule itself of the carboxylic acid ester compound is linear, and therefore, the second phenylene group is also preferably a p-phenylene group.

This second phenylene group is bonded to the naphthylene group via an ester bond.

As this naphthylene group, 1,4-naphthylene group, 1,5-naphthylene group, 1,6
-naphthylene group, 1,7-naphthylene group, 1.8-naphthylene group, 2.5-naphthylene group, 2.6-naphthylene group, 2.7-naphthylene group and 2.8-naphthylene group, etc. can. In particular, the carboxylic acid ester compound preferably has a linear molecule itself, and therefore, the naphthylene group is preferably 2,6-naphthylene group.

The other bond of this naphthylene group is bonded to the above R1.

Therefore, as the carboxylic acid ester compound represented by the above formula [A], specifically, for example, the following formulas [1] to [8]
Compounds represented by the following can be mentioned.

Shiri...[11 3...[2] Town...[3] Ul'3...[4] IFI (1-C12N25)-0#C00GC00GCooG
COO4,)5 "sCF co... [6] Su3...[7] Machi...[8] Among the above carboxylic acid ester compounds, phase transition of the compound represented by the following formula [4] The temperatures are shown in Table 1. Furthermore, Table 1
, the smectic C phase from SmC*I, S
mA represents smectic A phase, and IsO represents isoanalyte.

Town...[4]...[5] Table 1 ζ The above carboxylic acid ester compounds can be produced by using a combination of known synthesis techniques.

For example, the above carboxylic acid ester compound can be synthesized according to the synthetic route shown below. In addition, in the example of the reaction route shown below, the case where R1 is alkoxy is used as an example to explain the combination of carboxylic acid ester compounds.

That is, 6-alkoxy-2-carboxynaphthalene (i) and p-hydroxybenzoic acid benzyl ester (
ii) in the presence of an esterifying agent such as N,N'-dicyclohexylcarbodiimide to obtain 6-alkoxynaphthyl-2-carboxylic acid-4°-benzyloxycarbonylphenyl ester (iii) .

In this reaction, it is preferable to mix with a pyridine derivative such as 4-N,N-dialkylaminopyridine. In this case, it is preferable to use a halogenated hydrocarbon such as methylene chloride as the reaction solvent.

Next, the obtained 6-alkoxynaphthyl-2-carboxylic acid-4°-benzyloxycarbonylphenyl ester (iii) is heated with hydrogen in the presence of a reducing catalyst such as a palladium-carbon catalyst in a polar solvent such as tetrahydrofuran. Debenzylation is carried out by contacting with gas and reduction to obtain a compound having a carboxyl group at the terminal such as 6-alkoxynaphthyl-2-carboxylic acid-41-oxycarbonylphenyl ester (iv).

6-alkoxynaphthyl-2- thus obtained
6-alkoxynaphthalene-2-carboxylic acid-4' is obtained by reacting a compound having a carboxyl group at the terminal such as carboxylic acid 4'-oxycarbonylphenyl ester (1v) with a halogenating agent such as oxalic acid chloride.
- Obtain acid chlorides such as chloroformylphenyl ester (V).

6-alkoxynaphthalene-2 thus obtained
The alcohol to be reacted with -carboxylic acid-4°-chloroformylphenyl ester (V) can be synthesized, for example, as follows.

That is, when synthesizing an alcohol to be reacted with the above ester (V), first, 4-benzyloxybenzoic acid (vl) is reacted with a halogenating agent such as oxalic acid chloride to form 4-benzyloxybenzoic acid. Chloride (vii) is obtained.

Next, the obtained 4-benzyloxybenzoic acid chloride (vii) and a predetermined optically active alcohol (viii) are reacted and esterified to obtain 4-benzyloxybenzoic acid ester (1x). This is reduced and debenzylated by contacting it with hydrogen gas in a polar solvent such as tetrahydrofuran in the presence of a reduction catalyst such as a palladium-carbon catalyst. A compound having a hydroxy group at the end is obtained.

A compound having a hydroxy group at the terminal such as the 4-hydroxybenzoic acid ester (X) obtained in this way,
By reacting the previously synthesized acid chloride such as 6-alkoxynaphthalene-2carboxylic acid-4'-chloroformylphenyl ester (V) in a reaction solvent such as methylene chloride, the desired carboxylic acid ester can be obtained. derivatives can be obtained.

The liquid crystal compound used in the present invention can be synthesized by combining various reactions in addition to the synthesis method according to the reaction route as described above.

For example, when the carboxylic acid ester compound represented by formula [A] obtained as described above has optical activity,
This carboxylic acid ester compound comes to exhibit characteristics as a ferroelectric liquid crystal compound.

Among the above carboxylic acid ester compounds, many exhibit a smectic phase in a wide temperature range including around room temperature.

Hitherto, when a liquid crystal compound is used alone, there have been few known liquid crystal compounds that exhibit a smectic phase over a wide range of temperatures like this compound.

The liquid crystal composition containing the above-mentioned carboxylic acid ester compound used in the present invention not only exhibits a smectic phase over a wide temperature range, but also has an optical switching element manufactured using such a liquid crystal composition. It also has excellent high-speed response.

The liquid crystal composition used in the present invention contains at least one type of carboxylic acid ester compound [A] as described above. In the liquid crystal composition used in the present invention, the above-mentioned carboxylic acid ester compound [A] can be used, for example, as the main ingredient of a chiral smectic liquid crystal composition, or another compound exhibiting a smectic phase can be used as the main ingredient. It can also be used as an auxiliary agent for liquid crystal compositions.

In addition, liquid crystal compounds that exhibit ferroelectricity, such as the carboxylic acid ester compounds used in the present invention, cause optical switching phenomena when voltage is applied, so by utilizing this phenomenon, it is possible to improve responsiveness. A good display device can be created (for example, Japanese Patent Laid-Open No. 107216/1983)
(see Japanese Patent Application Laid-open No. 118744/1983).

Ferroelectric liquid crystal compounds used in such display devices include chiral smectic C phase, chiral smectic F phase, chiral smectic C phase, chiral smectic H phase, chiral smectic I phase, chiral smectic J phase, or chiral smectic It is a compound that exhibits one of the smectic phases, but display elements using such liquid crystal compounds generally have a low response speed (I,%) other than the chiral smectic C phase (SmC" phase).
(slow), so in the past, the response speed was large I/) (fast I/
'1) Driving with chiral smectic C phase was considered to be practically advantageous.

However, the method of driving a display element in the smectic A phase as already proposed by the present inventors (Japanese Patent Application No. 62-1
57808), the ferroelectric liquid crystal composition can be used not only in the chiral smectic C phase but also in the smectic A phase. Therefore, by using the liquid crystal composition of the present invention containing the above-mentioned carboxylic acid ester compound, it is possible to obtain a liquid crystal element with a wide range of liquid crystal temperatures and high speed electro-optic compatibility.

Table 2 shows an example in which the temperature range of a liquid crystal composition is widened by using the above carboxylic acid ester compound.

As shown in Table 2, the liquid crystal temperature range of the compound represented by the following formula (Cr-1) is from -6°C to -113°C.
-[4°-(6°゛-n-hebutyloxy-2°゛-naphthoyloxy)-benzoyloxy]benzoic acid R-1
"'-) Lifluoromethylheptyl ester (A-1)
By blending, the liquid crystal temperature range is widened from 96°C to 34°C, and a liquid crystal composition having a liquid crystal temperature range of as much as 6z°C can be obtained.

Town... (Cr-1) When producing the liquid crystal composition used in the present invention using the above-mentioned carboxylic acid ester compound, this liquid crystal compound can be used as a main ingredient, and can also be used as an auxiliary agent. It can also be used as

That is, in the liquid crystal composition used in the present invention, the content of the liquid crystal compound represented by the above formula [A] can be determined as appropriate in consideration of the characteristics of the liquid crystal compound used, the viscosity of the composition, the operating temperature, the intended use, etc. Can be set. In particular, this carboxylic acid ester compound (liquid crystal compound) is contained in an amount of 1 to 99% by weight based on the total weight of liquid crystal substances in the liquid crystal composition.
It is desirable to use an amount in the range of , preferably in the range of 5 to 75% by weight.

Furthermore, one or more types of carboxylic acid ester compounds represented by the above formula [A] may be blended in the liquid crystal composition.

In the liquid crystal composition used in the present invention, the above formula [A]
An example of a compound exhibiting a chiral smectic C phase that can be blended with the carboxylic acid ester compound represented by is (+)-4°-(2''-methylbutyloxy)phenyl-6-octyloxynaphthalene-2-
Carboxylic acid ester, 4°-decyloxyphenyl-6
-((+)-2'-methylbutyloxy)naphthalene-
Constituting a liquid crystal composition by blending a 2-carboxylic acid ester and a carboxylic acid ester compound represented by the above formula [A], which is a compound other than the above-mentioned compound exhibiting a chiral smectic C phase. Examples of liquid crystal compounds that can be used include biphenyl-based liquid crystal compounds such as , Schiff base-based liquid crystal compounds such as , azoxy-based liquid crystal compounds such as , terphenyl-based liquid crystal compounds such as , cyclohexyl-based liquid crystal compounds such as , and benzoyl-based liquid crystal compounds such as . In addition to nematic liquid crystal compounds such as acid ester liquid crystal compounds, cyclohexylcarboxylic acid ester liquid crystal compounds such as pyrimidine liquid crystal compounds, and cholesterin hydrochloride, cholesterin nonanoate, and cholesterin oleate. Cholesteric liquid crystal compounds and known smectic liquid crystal compounds can be mentioned.

In addition, when forming, for example, a display element using the above-mentioned liquid crystal composition, in addition to the above-mentioned carboxylic acid ester compound and other liquid crystal compounds, for example, a conductivity imparting agent and a life-enhancing agent are usually added. Additives that can be blended into the liquid crystal compound may also be blended.

Furthermore, when used in a liquid crystal element of a driving system that utilizes the dichroism of the dye, a dichroic dye may be added.

The liquid crystal composition used in the present invention can be produced by mixing the above carboxylic acid ester compound and, if desired, other liquid crystals and additives.

The liquid crystal element of the present invention can basically be manufactured by filling the gap between the cells as described above with a liquid crystal substance containing the above-mentioned carboxylic acid ester compound.

The liquid crystal material is typically heated to a molten state, and in this state is filled (injected) into the interstices of the evacuated cells.

After being filled with liquid crystal material in this manner, it is usually sealed.

Then, for example, the sealed cell is heated to a temperature above the temperature at which the liquid crystal material within the cell exhibits an isotropic phase, and then cooled to a temperature at which the liquid crystal material exhibits a liquid crystal phase. do.

Then, the temperature decreasing rate during this cooling is set to 2° C./min or less. Furthermore, it is preferable that the temperature decreasing rate be within the range of 0.1 to 2.0°C/min, and particularly preferably within the range of 0.1 to 0.5°C/min.

When cooling the cell in this way, by keeping the cooling rate within the above range, a liquid crystal element having a liquid crystal phase consisting of monodomains with excellent initial alignment and no alignment defects can be obtained. The initial orientation herein refers to the alignment state of the liquid crystal material before the orientation vector of the liquid crystal material is changed by applying a voltage or the like to the liquid crystal element.

The liquid crystal element obtained in this manner has extremely excellent contrast and the like.

Using the liquid crystal element according to the present invention, liquid crystal display devices and electro-optical display devices, such as white tiller type color display devices, cholesteric nematic phase change type display devices, and reverse domain prevention devices in TN type cells, are manufactured. can do.

Further, among the liquid crystal elements according to the present invention, a liquid crystal element filled with a liquid crystal composition exhibiting a smectic phase can be used as a memory type liquid crystal display element such as a thermal writing type display element or a laser writing type display element. A liquid crystal display device or an electro-optical display device can be manufactured using such a liquid crystal element.

Furthermore, by using a liquid crystal composition containing a carboxylic acid ester compound having ferroelectric properties, in addition to the above-mentioned applications, liquid crystal elements such as optical switching elements such as optical shutters and liquid crystal printers, piezoelectric elements and pyroelectric elements can be used. It can be preferably used as a liquid crystal element, and a liquid crystal display device or an electro-optical display device can be manufactured using such a liquid crystal element. That is, when a chiral smectic C phase is formed using the liquid crystal material used in the present invention, the chiral smectic C phase exhibits bistability. Therefore, optical switching and display can be performed using this liquid crystal element by reversing the electric field between two stable states.

Further, since such a ferroelectric liquid crystal material exhibiting a chiral smectic C phase has spontaneous polarization, when a -degree voltage is applied, it has a memory effect even after the electric field is erased. Therefore, if this memory effect is utilized, there is no need to continue applying voltage to the liquid crystal element, and therefore it is possible to reduce power consumption in a display device made of such a liquid crystal element. Furthermore, in this case the contrast of the display device is stable and yet very sharp.

In addition, in a switching element obtained using a liquid crystal composition (compound) exhibiting this chiral smectic C phase, switching is possible simply by changing the orientation direction of the molecules, and in this case, the primary term of the electric field strength becomes the driving force. In order to act,
Liquid crystal elements can be driven with low voltage.

By using this switching element, it is possible to achieve a high-speed response of several tens of microseconds or less, which greatly reduces the scanning time for each element, making it possible to manufacture large-screen displays (liquid crystal display devices) with many scanning lines. I can do it.

Moreover, since this display operates at room temperature or even lower temperatures (see Table 4), it can be easily scanned without the use of auxiliary means for temperature control.

Furthermore, even in the smectic A phase, which does not have bistability, the molecules of the liquid crystal substance used in the liquid crystal element of the present invention are induced to tilt when an electric field is applied. This property can be used to perform optical switching. I can do it.

As mentioned above, a ferroelectric liquid crystal compound has a chiral smectic C phase, a chiral smectic F phase, a chiral smectic C phase, a chiral smectic H phase, a chiral smectic I phase, a chiral smectic J phase, or a chiral smectic phase due to the structure of the liquid crystal substance. However, except for the chiral smectic C phase (SmC$ phase), liquid crystal elements using such liquid crystal compounds generally have a slow response speed. It was believed that phase driving was advantageous in practice. However, according to the method of driving a display element in the smectic A phase and the display element that can be driven in the smectic A phase (Japanese Patent Application No. 157808/1983), which the present inventors have already proposed, the above-mentioned It is possible to drive not only the chiral smectic C phase but also the smectic A phase.

Furthermore, the liquid crystal substance used in the liquid crystal element of the present invention exhibits two or more stable states even in a liquid crystal phase such as a chiral smectic F phase, which has a higher order than the chiral smectic C phase. Optical switching can be performed in a similar manner.

Specific examples of display methods using the liquid crystal element of the present invention include the following methods.

The first method is to interpose the liquid crystal element of the present invention between two polarizing plates, apply an external electric field to this liquid crystal element, and change the orientation vector of the ferroelectric liquid crystal compound. This is a method of displaying using the birefringence of a ferroelectric liquid crystal compound.

A second display method using the liquid crystal element of the present invention uses a liquid crystal composition containing a dichroic dye as the liquid crystal composition,
This method utilizes the dichroism of dyes, and this method performs display by changing the absorption wavelength of light by the dye by changing the alignment direction of molecules in a ferroelectric liquid crystal composition. The dye used in this case is usually a dichroic dye, and examples of such dichroic dyes include azo dyes, naphthoquinone dyes, cyanine dyes, and anthraquinone dyes.

In addition to the display methods described above, the liquid crystal element according to the present invention can also be employed in various commonly used display methods.

Further, a liquid crystal display device and an electro-optic display device manufactured using the liquid crystal element according to the present invention can be statically driven,
It can be driven by driving methods such as electrical address display such as simple matrix drive and complex matrix drive, optical address display, thermal address display, and electron beam address display.

Effects of the Invention Since the liquid crystal element of the present invention uses a liquid crystal material containing a novel carboxylic acid ester compound having a trifluoromethyl group, it operates when the contrast is particularly high and the switching speed is also high.

Furthermore, since the liquid crystal composition used in the present invention contains a carboxylic acid ester compound having a trifluoromethyl group, this composition exhibits a smectic phase even in a wide temperature range including room temperature, and exhibits antiferroelectric properties. Used as a liquid crystal composition.

Further, in the present invention, since the liquid crystal element is molded by the method described above, it is possible to easily manufacture a liquid crystal element having particularly excellent contrast as described above.

Furthermore, in a liquid crystal display device, an electro-optical display device, or an optical switching device manufactured using such an element, not only can the scanning time be significantly shortened, but also it can be used at a temperature below room temperature.

Further, since the liquid crystal material used in the present invention can contain a carboxylic acid ester compound having spontaneous polarization, a device having a memory effect even after the electric field is erased can be obtained.

Such devices have low power consumption and stable contrast. Low voltage drive is also possible. Such devices utilize the bistability of carboxylic acid ester compounds in the smectic phase, so
It is preferably used for optical switching at temperatures below room temperature.

Next, examples of the present invention will be shown, but the present invention is not limited to these examples. In addition, the symbols R and S in the compound formulas used in the following general examples and examples respectively mean the R form and the 5 form among optical isomers.

Synthesis Example 1 4-[4°-(6”-n-hebutyloxy-2-naphthoyloxy)-benzoyloxy]-benzoic acid R-1”
1.14 g (5 mmol) of 4-benzyloxybenzoic acid
, R-1-)lifluoromethyl-heptatool 0.92
g (5 mmol), 0.12 g (l mmol) of 4-N,N-dimethylaminopyridine and 20 ml of methylene chloride.
A methylene chloride solution containing 1.03 g (5 mmol) of N,N'-dicyclohexylcarbodiimide was added to a mixture of
0 ml of the solution was added dropwise at room temperature over 1 hour while stirring.

The mixture was further reacted at room temperature for 10 hours. The reaction mixture was filtered and the resulting filtrate was concentrated. The concentrate was separated using column chromatography to obtain 1.75 g (4.4 mmol) of 4-benzyloxybenzoic acid R-1°-trifluoromethyl-heptyl ester as a colorless and transparent liquid.

2nd stage 4-benzyloxybenzoic acid R-1 obtained in the 1st stage
'-) Lifluoromethyl-heptyl ester 1.58g
(4 mmol), 0.5 g of 5% palladium-carbon catalyst, and 30 ml of ethyl acetate was bubbled with hydrogen at room temperature, normal pressure, and stirring for 9 hours.

The reaction mixture was filtered using Celite, a filter aid, and the resulting filtrate was concentrated. By separating the concentrate using column chromatography, 1.13 g (3.7 mmol) of 4-hydroxybenzoic acid R-1°-trifluoromethyl-heptyl ester was obtained as a colorless viscous liquid. .

Third stage 2.43 g (8.5 mmol) of 6-n-hebutyloxy-naphthalene-2-carboxylic acid, 1.94 g (8.5 mmol) of 4-hydroxybenzoic acid benzyl ester, 4
-N.

In a mixture of 0.012 g (0.1 mmol) of N-dimethylaminopyridine and 30 ml of methylene chloride, N,
'-Dicyclohexylcarbodiimide 1.75 g (8
, 5 mmol) was added dropwise over 1 hour while cooling with water and stirring. 12 more at room temperature
Allowed time to react.

The reaction mixture was filtered and the resulting filtrate was concentrated.

By separating the concentrate using column chromatography, 2.72 g (5.5 mmol) of 4-(6′-n-hebutyloxy-2°-naphthoyloxy)-benzoic acid benzyl ester as a white solid was obtained. I got it.

4-(6'-n-hebutyloxy-) obtained in the 3rd step
Hydrogen was added to a mixture of 2.33 g (4.7 mmol) of benzyl 2°-naphthoyloxy)-benzoate, 1.0 g of 5% palladium-carbon catalyst and 30 ml of tetrahydrofuran at room temperature and normal pressure under stirring. I blew it for 8 hours.

The reaction mixture was filtered using Celite as a filter aid,
The resulting filtrate was concentrated. By recrystallizing the concentrate from toluene, 1.4% of 4-(6°-n-heptyloxy-2°-naphthoyloxy)-benzoic acid was obtained as a white solid.
2 g (3.5 mmol) were obtained.

Fifth step 4-(6°-n-hebutyloxy-
0.41 g (1 mmol) of 2'-naphthoyloxy)-benzoic acid, 0.41 g (1 mmol) of 4-hydroxybenzoic acid R-1'-trifluoromethyl-heptyl ester obtained in the second stage.
30 g (1 mmol), 0.012 g (0.1 mmol) of 4-N, N-dimethylaminopyridine and 0.21 g (1 mmol) of N,N'-dicyclohexylcarbodiimide in a mixture of 30 ml of methylene chloride. 2 ml of methylene solution was added dropwise at room temperature with stirring over 2 hours.

The reaction was further continued at room temperature for 8 hours. Filter the reaction mixture;
The resulting filtrate was concentrated. By separating the concentrate using column chromatography, a melting point of 177-17
Obtained 0.63 g of a white solid at 8°C.

The value of the FD-mass spectrum of this solid is m/e=6
92, and FIG. 2 shows the I H-NMR of this compound.
A spectrum chart was shown. Based on the results of these analyses, this compound has the desired 4-[4'-(6''-n
-heptyloxy-2'°-naphthoyloxy)-benzoyloxy]-benzoic acid R-1''-)lifluoromethylheptyl ester.

Yield, 88 mol% The measurement results of the phase transition temperature of this compound are shown below.

73℃ 124℃ 177℃73℃
125°C 183°C In the above, Cry represents the crystalline phase, SmC" represents the chiral smectic C phase, and SmA
represents the smectic A phase and Iso represents the isotropic liquid.

Preparation of liquid crystal composition Next, the carboxylic acid ester compound represented by the formula (A-1) obtained as described above and the compound represented by the following formula (Cr-1) were mixed in a weight ratio of 51:49. A liquid crystal composition used in the present invention was prepared by mixing at the same ratio.

...(Cr-1) The phase transition temperature of this composition was measured. The results are also listed in Table 3.

Furthermore, the phase transition temperature of the compound represented by the above formula (Cr-1) is also listed in Table 3.

Synthesis Example 2 4-[4°-(6”-n-decyloxy-2°”-naphthoyloxy)-benzoyloxy]-benzoic acid R-1
``'-) Synthesis of refluoromethylheptyl ester 1st step 6-decyloxynaphthalene-2-carboxylic acid 3.01
g (8.0 mmol), 4-hydroxybenzoic acid benzyl ester 1.80 g (8.0 mmol), 4-N,
In a mixture of 0.012 $2 (0.1 mmol) of N-dimethylaminopyridine and 30 ml of diethyl ether,
N,N'-dicyclohexylcarbodiimide 1.63g
15ml of diethyl ether solution containing (8.0 mmol)
1 was added dropwise over 1 hour while cooling with water and stirring. The mixture was further reacted at room temperature for 30 hours. The reaction mixture was filtered and the resulting filtrate was concentrated. The concentrate was separated using column chromatography to obtain 3.34 g (5.7 mmol) of 6-decyloxynaphthyl-2-carboxylic acid-4°-benzyloxycarbonylphenyl ester as a white solid. .

Yield: 2 mol% 2nd stage 2.93 g (5 mmol) of 6-decyloxynaphthyl-2-carboxylic acid-4'-benzyloxycarbonylphenyl ester obtained in the 1st stage, 5% palladium-carbon catalyst 0 Hydrogen gas was passed into a mixture of .29 g and 20 ml of tetrahydrofuran at room temperature for 20 hours with stirring.

The 5% palladium-carbon catalyst was then filtered off and the filtrate was concentrated. The obtained concentrate was recrystallized using acetone to obtain 2.28 g (4.60 mmol) of 6-decyloxynaphthyl-2-carboxylic acid-4°-carboxyphenyl ester as a white solid. .

Yield: 92 mol% Third step 0.57 g (2.5 t remol) of 4-benzyloxybenzoic acid and 2.13 ml (25 t remol) of oxalic acid chloride in large excess
mmol) was added thereto, and the mixture was heated under reflux at 70°C for 3 hours.

After cooling, oxalic acid chloride was removed from the reaction mixture under reduced pressure to obtain a white solid.

R-1,1,1-)Refluoro-2-octatool0.
260 g (2.0 mmol), pyridine 1, 6 ml
(20 mmol) and 25 ml of a tetrahydrofuran solution containing the white solid prepared as described above in a mixture of 50 ml of a tetrahydrofuran solution containing 0.012 g (0.1 mmol) of 4-N,N-dimethylaminopyridine.
ml was added dropwise over 20 minutes under water cooling and stirring.

The mixture was further stirred at room temperature for 7 hours. The reaction mixture was poured into water, and the reaction product was extracted from this aqueous mixture using diethyl ether. The extract was washed with water and then concentrated. By separating the concentrate using column chromatography, a white solid, R-4-benzyloxybenzoic acid, was obtained.
(1′-trifluoromethylheptyl)ester 0.7
4 g (1.9 mmol) were obtained.

Yield: 94 mol% 4th stage R-4-benzyloxybenzoic acid obtained in the 3rd stage
(1'-trifluoromethylheptyl)ester17.
Hydrogen gas was passed through a mixture of 9 g (52.6 mmol), 1.8 g of 5% palladium-on-carbon catalyst and 100 ml of ethanol for 10 hours at room temperature with stirring.

The 5% palladium-carbon catalyst was then filtered off and the filtrate was concentrated. The obtained concentrate was recrystallized using acetone to obtain 16.0 g (52.6 mmol) of R-4-hydroxybenzoic acid-(1'-trifluoromethylhebutyl) ester as a white solid. Obtained.

Yield: 100 mol% 5th stage 6-decyloxynaphthyl-2-carboxylic acid-4'-carboxyphenyl ester obtained in the 2nd stage 0,34
g (0.75 mmol) of oxalyl chloride 0
．． 64 g (7.5 mmol) was added, and the mixture was heated under reflux at 80° C. for 5 hours. After the reaction mixture was allowed to cool, oxalyl chloride was removed by reducing the pressure to obtain a white solid.

R-4-hydroxybenzoic acid-(1
°-trifluoromethylheptyl)ester 0,19
g (0.75 mmol), pyridine 0.60 ml (7
, 5 mmol) and 4-N, N-dimethylaminopyridine (0.012 g (0.1 mmol)), 10 ml of the tetrahydrofuran solution containing the white solid was added to the mixture with stirring under water cooling,
It was added dropwise over 10 minutes. The mixture was further stirred at room temperature for 12 hours. When the reaction mixture was poured into water, a white powder was obtained, which was filtered.

By separating the white solid obtained by filtration using column chromatography, a solid with a melting point of 164 to 165°C was obtained.
33g was obtained.

When this solid was measured using FD-mass spectroscopy, the m/e value was 734.

Further, FIG. 3 shows a chart of the IH-NMR spectrum of this compound.

From the results of these analyses, this compound has the desired 4-
[4°-(611-n-decyloxy-21-naphthoyloxy)-benzoyloxy]-benzoic acid R-11°
-trifluoromethylheptyl ester.

Yield: 44 mol% The measurement results of the phase transition temperature of this compound are shown below.

60℃ 134℃ 164℃85℃
134℃ 164℃ Above Cr
y is the crystalline phase, SmC" is the chiral smectic C phase,
SmA indicates a smectic A phase, and Iso indicates an isotropic liquid.

Preparation of liquid crystal composition Next, the carboxylic acid ester compound represented by the formula [2] obtained as described above, that is, 17B...[2] and the following formula (Cr-
1), (Cr-2), and the compound represented by (A-1) of the present invention were mixed to produce a liquid crystal composition of the present invention.

3...(Cr-1) Lr...(Cr-2) "a...(A-1) The phase transition temperature of this composition was measured. The results are also listed in Table 4. .

Furthermore, the above formulas (Cr-1), (Cr-2), (A-
The phase transition temperature of the compound represented by 1) is also listed in Table 4.

Synthesis Example 3 4-[4°-(6”-n-hexadecyloxy-2-naphthoyloxy)-benzoyloxy]-benzoic acid R-
Synthesis of 1''-)lifluoromethylheptyl ester 1st step 4.94 g (12 mmol) of 6-n-hexadecyloxy-naphthalene-2-carboxylic acid, 2.74 g (12 mmol) of 4-hydroxybenzoic acid benzyl ester ), 4
-N, to a mixture of 0.12 g (1 mmol) of N-dimethylaminopyridine and 40 ml of methylene chloride, N,
N'-dicyclohexylcarbodiimide 2.48g (1
12 ml of methylene chloride solution containing 2 mmol) was cooled with water,
The mixture was added dropwise over 2 hours while stirring. The reaction was further continued at room temperature for 12 hours.

The reaction mixture was filtered and the resulting filtrate was concentrated.

By separating the concentrate using column chromatography, 3.73 g (6.0 mmol) of solid 4-(6'-n-hexadecyloxy-2°-naphthoyloxy)-benzoic acid pendyl ester ) was obtained.

Second stage: 3.04 g (4.9 mmol) of 4-(6'-n-hexadecyloxy-2°-naphthoyloxy)-benzoic acid benzyl ester obtained in the first stage, 5% palladium-
Hydrogen was bubbled into a mixture of 1.5 g of carbon catalyst and 50 ml of ethyl acetate at room temperature and normal pressure with stirring for 8 hours. The reaction mixture was filtered using Celite, a filter aid, and the resulting filtrate was concentrated to obtain solid 4-(6°-n-hexadecyloxy-2°-naphthoyloxy)benzoic acid 2.
．． 51 g was obtained.

Third stage 90.53 g (1
0.30 g (1 mmol) of 4-hydroxybenzoic acid R-1''-)lifluoromethylheptyl ester obtained in the second step of Example 2, 0.30 g (1 mmol) of 4-N,N-dimethylaminopyridine. 012 g (0.1 mmol) and 30 ml of methylene chloride, N,N'-
2 ml of a methylene chloride solution containing 0.21 g (1 mmol) of dicyclohexylcarbodiimide was added at room temperature with stirring.
It dripped in time. The reaction was continued for an additional 12 hours. The reaction mixture was filtered and the resulting filtrate was concentrated. By separating the concentrate using column chromatography, 4 sg of solid o with a melting point of 128.0 to 128.5°C was obtained.

The value of the FD-spectrum of this solid is m/e = 81
8, and Figure 4 shows the + )(-NM
A chart of the R spectrum is shown. From these analysis results, this compound was found to be the target R-1''-trifluoromethylheptyl 4-[4°-(6-n-hexadecyloxy-2-naphthoyloxy)-benzoyloxy]-benzoate. It was identified as an ester. Yield: 54 mol% The measurement results of the phase transition temperature of this compound are shown below.

32°C 109°C 133°C In the above, Cry represents a crystalline phase, SmC" represents a chiral smectic C phase, SmA represents a smectic A phase, and Iso represents an isotropic liquid.

Example 1 As shown in Fig. 1, an alignment control film (thickness) made of polyimide (LX-1400 manufactured by Hitachi Chemical Co., Ltd.) was rubbed on the inner surfaces of two transparent electrode substrates so that the alignment control directions were opposite to each other. The carboxylic acid ester compound (4) produced in Synthesis Example 1 above was melted and injected into the cells each having a diameter of 150 angstroms, with the gap between the cells under reduced pressure.

After filling the liquid crystal material in this way, the cell was heated to 185°C.
After heating to 185° C. for 5 minutes, the liquid crystal device was cooled to 80° C. at a rate of 1° C./min.

When the contrast of the obtained liquid crystal element was measured, it was found to be 3.
It was 5.

Note that the above cell was created by the method described below.

Cell conditions (a) External dimensions: 2.5cm long x 2.2cm wide
× Thickness 1.5 mm (b) Substrate; Thickness Q, 7 mm, substrate material (glass) (c) Distance between substrates: 2 μm (d) Side wall dimensions: length 1.8 cm x width 0.1 cm x thickness 2
Polyimide was applied onto a glass substrate with a μm ITO transparent electrode film. That is, polyimide (manufactured by Hitachi Chemical Co., Ltd., L
X-1400) was applied onto an ITO transparent electrode by a spin code method. Polyimide was diluted to 1.2% using N-methylpyrrolidone as a solvent and spin-coded at 2000 rpm. When this was heated at 325° C. for 3 minutes and cured, a polyimide film with a thickness of 150 to 200 angstroms was created.

Next, the formed polyimide film was rubbed in one direction with a nylon cloth to impart liquid crystal orientation.

An evaluation cell was created by stacking two glass substrates coated with the polyimide film thus created.

First, an epoxy adhesive was applied by silk printing onto a glass substrate coated with a polyimide film in order to control the adhesion between the two substrates and the cell gap.

The epoxy adhesive is the main adhesive (manufactured by EHC■, LCB-
304B), curing agent (manufactured by EHC■, LCB-310B)
and beads for cell gap control (manufactured by EHC■, GP
-20) were mixed at a ratio of 138:30:3. Apply epoxy adhesive to one of the two glass substrates,
They were attached so that the polyimide films faced each other. This epoxy adhesive was cured under the following conditions: 50'CI for 5 minutes, 60'CI for 5 minutes, 70°C for 15 minutes, 80°C for 15 minutes, 125°C for 30 minutes, and 170°C for 60 minutes.

The liquid crystal material was evaluated using the evaluation cell with a cell gear diameter of approximately 2 μm.

In addition, in the present invention, the contrast is determined by placing a liquid crystal element between orthogonal polarizers, rotating this liquid crystal element, and measuring the transmitted light intensity (I) in open and dark conditions.
/ (dark time) was calculated and determined.

A liquid crystal device was manufactured in the same manner as in Example 1 except that the cooling rate was changed to 0.1° C./min.

The contrast of this liquid crystal element was 50.

Example 3 Same as Example 1, except that the composition obtained in "Preparation of liquid crystal composition" in Example 1 was used instead of the carboxylic acid ester compound, and the composition was cooled to 40 ° C. A liquid crystal device was manufactured.

The contrast of this liquid crystal element was 46.

Comparative Example 1 In Example 1, the rubbing direction (
A liquid crystal element was manufactured in the same manner as in Example 1, except that the orientation directions (orientation directions) were changed to the same direction parallel to each other, and the cooling rate was changed to 10° C./min.

The contrast of the obtained liquid crystal element was 6.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing a cross section of a liquid crystal element of the present invention. la, lb...Transparent substrate (e.g. glass, transparent plastic such as polycarbonate) 2...Cell 3...Cell gap 4...Liquid crystal material 5a, 5b...-Electrode (e.g. lN-8n oxide )6
a, 6b... Orientation control film 7... Spacer IH-NMR spectrum chart. Figure 2 shows 4-[4°-(6”-n-hebutyloxy-
2 is a chart of the IH-NMR spectrum of 2-naphthoyloxy)-benzoyloxy]-benzoic acid R-1'-trifluoromethylheptyl ester. Figure 3 shows the I
It is a chart of H-NMR spectrum.

Claims (1)

[Claims] (1) In a liquid crystal element in which a gap between cells formed by two opposing substrates is filled with a liquid crystal substance, an alignment control film is provided on the inner surface of each of the two substrates. The alignment processing directions of the two alignment control films are substantially parallel and opposite, and the liquid crystal substance contains a carboxylic acid ester compound represented by the following formula [A]. Liquid crystal element; ▲There are mathematical formulas, chemical formulas, tables, etc.▼ ... [A] [However, in formula [A], R^1 is a carbon number of 6 to 1
8 alkyl group, an alkoxy group having 6 to 18 carbon atoms, and a halogenated alkyl group having 6 to 18 carbon atoms, m is an integer of 1 to 10,
C^* represents an asymmetric carbon atom]. (2) The liquid crystal element according to claim 1, wherein at least one of the alignment control films is a polyimide film. (3) The liquid crystal element according to claim 1 or 2, wherein the alignment treatment method for the alignment control film is a rubbing treatment method. (4) The liquid crystal element according to claim 1, wherein R^1 in formula [A] is an alkoxy group having 6 to 18 carbon atoms, and m is 5. (5) The liquid crystal substance contains a compound represented by formula [A] from 1 to 99
The liquid crystal element according to claim 1, which is a liquid crystal composition containing % by weight. (6) When manufacturing a liquid crystal element in which a liquid crystal substance is filled in the gap between cells formed by two facing substrates, alignment control films are formed on the inner surfaces of the two substrates, and the alignment treatment is performed. The directions are substantially parallel and opposite to each other to form a cell, and the gap between the cells is filled with a liquid crystal substance containing a carboxylic acid ester compound represented by the following formula [A]. After heating above the temperature at which the liquid crystal substance contained exhibits an isotropic phase, 2
A method of manufacturing a liquid crystal element that involves cooling the liquid crystal material to a temperature below the temperature at which it becomes a liquid crystal at a cooling rate of ℃/min or less; ▲There are mathematical formulas, chemical formulas, tables, etc.▼ ... [A] [However, In [A], R^1 is a carbon number of 6 to 1
8 alkyl group, an alkoxy group having 6 to 18 carbon atoms, and a halogenated alkyl group having 6 to 18 carbon atoms, m is an integer of 1 to 10,
C^* represents an asymmetric carbon atom]. (7) The method for manufacturing a liquid crystal element according to claim 6, wherein at least one of the alignment control films is a polyimide film. (8) The method for manufacturing a liquid crystal element according to claim 6 or 7, wherein the alignment treatment method for the alignment control film is a rubbing treatment method. (9) A liquid crystal display device using the liquid crystal element according to any one of claims 1 to 5. (10) An electro-optical display device using the liquid crystal element according to any one of claims 1 to 5. (11) An optical switching device using the liquid crystal device according to any one of claims 1 to 5.