JP2001192348A - Liquid crystalline optically active compound and liquid crystal composition, optical film and recording medium each using the same, and method for producing the compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optically active liquid crystalline compound exhibiting cholesteric liquid crystal phase in itself and having high voltage retention, to provide a liquid crystal composition, optical film and recording medium each containing the above compound, and to provide a method for producing the above compound. SOLUTION: This compound is an optically active 3,5-difluoro-1-[4-(trans-4- substituted cyclohexyl)cyclohexen-1-yl]benzene of the general formula (I) (wherein, R is a 1-10C straight-chain, alkyl, alkenyl or alkynyl group). The 2nd objective liquid crystal composition, the 3rd objective optical film and the 4th objective recording medium contain the above compound, respectively. The other objective method for producing the above compound is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel optically active 3,5-difluoro-1- [4- (trans-4-) which is useful for electro-optical display materials, optical films and recording media.
[Substituted cyclohexyl) cyclohexen-1-yl] benzene, a liquid crystal composition containing the same, an optical film and a recording medium, and a method for producing the compound.

[0002]

2. Description of the Related Art Liquid crystal display devices are widely used in watches, calculators, word processors, portable PCs, monitors for desktop PCs, TVs, mobile phones, and the like. The liquid crystal display system includes a TN type, STN type, guest host type, ferroelectric liquid crystal, antiferroelectric liquid crystal, phase transition type, ECB type (hybrid alignment and vertical alignment), IPS type, and the like. In recent years, as display elements have been increased in size and display capacity has been increased, there has been a strong demand for liquid crystal materials having lower viscosity, lower optical anisotropy and higher voltage holding ratio. In order to solve the problem, a fluorine-based liquid crystal compound has been put to practical use. For example, JP-B-63-13411 describes 4- [trans-4 (trans-4-alkylcyclohexyl) cyclohexyl] fluorobenzene which is a fluorine-based nematic liquid crystal.

[0003]

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As a fluorine-based nematic liquid crystal compound, JP-A-5-310618 discloses 4- [trans-4 '-(trans-4 "-alkylcyclohexyl) cyclohexyl] -3,5 according to the following reaction formula. -Synthesis of difluorobenzene is disclosed.

[0005]

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At present, TN and STN, which are the most widely used liquid crystal operation modes, need to contain an optically active substance in a liquid crystal composition in order to generate a desired liquid crystal twist angle. For example, optically active having a cyano group such as cholesteryl chloride, optically active 4-cyano-4 '-(2-methylbutyloxy) biphenyl, and optically active 4-cyano-4'-(2-methylbutyl) biphenyl. A substance is added to the liquid crystal. However, when these compounds are added, there is a problem that the high voltage holding ratio required for the liquid crystal used in the TFT driving method is reduced.

Further, in the reaction formula of the above-mentioned JP-A-5-310618, 3,5-difluoro-1- [4- (trans-4-substituted cyclohexyl) is represented by formula (IV).
[Cyclohexen-1-yl] benzene is indicated.
However, the above-mentioned publication does not disclose any description concerning the properties of the compound or the like, in particular, nothing concerning the optical activity of the compound. Further, when the cyclohexene group is simply reduced as shown in (IV) to (V), most of the compound is obtained as a cis form and a trans form is not obtained. Has adopted a method of directly reducing the following compound without passing through a cyclohexene derivative.

[0008]

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Therefore, in the process of synthesizing the nematic liquid crystal compound described in JP-A-5-310618, it is practically almost impossible to find out the chemical properties of the cyclohexene compound, particularly the properties relating to optical activity. It is possible.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an optically active liquid crystalline compound which exhibits a cholesteric liquid crystal phase by itself and has a high voltage holding ratio. Liquid crystal composition further comprising the compound, an optical film and a recording medium,
And a method for producing the compound.

[0011]

The object of the present invention can be attained by providing the following optically active liquid crystal compound, liquid crystal composition, optical film and recording medium. (1) An optically active 3,5- compound represented by the following general formula (I)
Difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene.

[0012]

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In the formula, R represents a linear alkyl group, alkenyl group or alkynyl group having 1 to 10 carbon atoms. (2) The optically active 3,5- represented by the above general formula (I)
A liquid crystal composition containing difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene. (3) An optically active 3,5- compound represented by the above general formula (I)
An optical film containing difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene. (4) An optically active 3,5- compound represented by the above general formula (I)
A recording medium containing difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene. (5) Optically inactive 3,5 represented by the above general formula (I)
Including the step of recrystallizing -difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene, comprising the optically active 3,5-difluoro- represented by the above general formula (I). 1- [4- (trans-4-
A method for producing a substituted cyclohexyl) cyclohexen-1-yl] benzene.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The compound represented by the general formula (I)
Optical properties of 5-difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene (where R is a linear alkyl, alkenyl, or alkynyl group having 1 to 10 carbon atoms) The active liquid crystalline compound has a low viscosity, a small optical anisotropy, a high voltage holding ratio and a high TF
It is a compound most suitable for a liquid crystal composition for a T drive type liquid crystal display device. Since the optically active liquid crystal compound of the present invention exhibits a cholesteric liquid crystal phase, it exhibits blue selective reflection based on a cholesteric helical structure. In addition, since the compound alone has a cholesteric phase as described above, the liquid crystal temperature range does not greatly change due to the addition of the compound. In addition, the compatibility with the non-chiral liquid crystal material used in the TFT driving method is very good. More specifically, in the general formula (I), when R is a propyl group, the compound exhibits a cholesteric phase in a high temperature range of 70 ° C. to 87 ° C. in a wide temperature range, and has a low viscosity as a remarkable property to a fluorine liquid crystal. And the properties of the composition are not changed by mixing the compounds.

Next, the method for producing the optically active liquid crystalline compound of the present invention will be described. Conventionally, as an optically active liquid crystalline compound added to a liquid crystal composition, a compound in which a liquid crystalline skeleton (mesogen) is substituted with an optically active substituent is used in addition to a cholesterol derivative. As the method, a synthesis method using a compound having an optically active alkyl group as a raw material is used. However, in the method for producing the compound of the present invention described in detail below, a raw material having no asymmetric carbon can be used as a starting material. The asymmetric carbon is generated in the molecule after the reaction, and a racemate having the asymmetric carbon in the molecule is obtained. The racemate can be easily optically resolved as described below, and does not require a complicated racemic resolution step, so that an optically active liquid crystalline compound can be produced at low cost.

In order to produce the optically active liquid crystal compound of the present invention, first, as shown in the following reaction formula, an optically inactive 3,5-difluoro-1- [4- (trans-4-substituted cyclohexyl) is used. ) Cyclohexen-1-yl] benzene. That is, Grignard reaction of 4- (trans-4-substituted cyclohexyl) cyclohesanone with 3,5-difluorofelmagnesium bromide, followed by dehydration with p-toluenesulfonic acid, gives an optically inactive 3,5-. Difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene is obtained. This compound has an asymmetric carbon in the skeleton of the molecule, but can be obtained as a racemate according to the above method.

[0017]

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The racemic compound can be easily optically resolved by recrystallization, for example, as described below. For example, the substance obtained by the above-mentioned synthesis method is dissolved in about 5 to 30% by weight of the solvent using hexane, ethyl acetate, acetone or the like as a solvent, and the ambient temperature is reduced to 10%.
As an example, a method of performing recrystallization under the condition that the temperature is maintained at ２０20 ° C. and left for 24 hours to 6 days. Before performing such recrystallization, ordinary recrystallization that is simpler than the above-described recrystallization may be performed. When the recrystallization is performed as described above, the S-form or the R-form is first separated, and the R-form or the S-form, which is an enantiomer of the optical isomer precipitated in the mother liquor, remains, and optical resolution can be performed. At this time, it is preferable to make a crystal as large as possible. For example, a large crystal can be produced by leaving it in a supersaturated state for a long time. The optical purity can be increased not only once but also as necessary by repeating recrystallization a plurality of times. Further, one enantiomer remaining in the mother liquor in a large amount can be obtained by concentrating and recovering the solvent of the mother liquor, and then performing similar recrystallization. Since the optically active liquid crystalline compound of the present invention exhibits a cholesteric phase and has a twisted structure, its optical activity can be specified by determining the helical pitch. For example, the canoe edge method can be used. Matsumura, Iwayanagi: “Applied Physics”, 43, 125 (197)
As described in 4), this is a method of calculating a helical pitch from the interval between disclination lines generated in a wedge-shaped cell whose surface has been rubbed. When the helical pitch is short and close to the optical wavelength, the selective reflection wavelength (λ
₀ = n × p) (n is the average refractive index of the liquid crystal, and p is the helical pitch).

All optically active liquid crystal compounds represented by the general formula can be produced by the above method, and specific compounds are shown below. Optically active 3,5-difluoro 1- [4- (trans-4
-Methylcyclohexyl) cyclohexen-1-yl]
Benzene optically active 3,5-difluoro 1- [4- (trans-4
-Ethylcyclohexyl) cyclohexen-1-yl]
Benzene optically active 3,5-difluoro 1- [4- (trans-4
-Propylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Butylcyclohexyl) cyclohexen-1-yl]
Benzene optically active 3,5-difluoro 1- [4- (trans-4
-Pentylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Hexylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Heptylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Octylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro1- [4- (trans-4)
-Nonylcyclohexyl) cyclohexen-1-yl]
Benzene optically active 3,5-difluoro 1- [4- (trans-4
-Decylcyclohexyl) cyclohexen-1-yl]
benzene

Optically active 3,5-difluoro 1- [4-
(Trans-4-ethenylcyclohexyl) cyclohexen-1-yl] benzene Optically active 3,5-difluoro 1- [4- (trans-4
-Propenylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Butenylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Pentenylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Hexenylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Heptenylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Octenylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Nonenylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Decenylcyclohexyl) cyclohexen-1-yl] benzene

Optically active 3,5-difluoro 1- [4-
(Trans-4-ethynylcyclohexyl) cyclohexen-1-yl] benzene Optically active 3,5-difluoro 1- [4- (trans-4
-Propynylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Butynylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro1- [4- (trans-4
-Pentynylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Hexynylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Heptynylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Octynylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Noninylcyclohexyl) cyclohexen-1-yl] benzene optically active 3,5-difluoro 1- [4- (trans-4
-Decynylcyclohexyl) cyclohexen-1-yl] benzene

The liquid crystal composition containing the optically active liquid crystal compound of the present invention can be used in various liquid crystal devices (TN device, STN device, guest host device, selective reflection device, Phase transition type element). When the compound of the present invention is added to the liquid crystal, a very useful function, which does not exist in the racemic form, such as inducing a helical structure or spontaneous polarization in the liquid crystal phase, is exhibited. The helical structure in the nematic phase is indispensable in STN and TN devices. By shortening the period, it becomes possible to impart scattering and selective reflection characteristics to the liquid crystal phase. The compound of the present invention is characterized in that it is a substance having a liquid crystal phase and a high voltage holding ratio in terms of chemical structure, but is optically active. Therefore, by mixing the present compound with a liquid crystal, the liquid crystallinity of the composition is not impaired or phase separation does not occur. Furthermore, any of the enantiomers can be similarly synthesized, and by adjusting the mixing ratio thereof, a desired helical pitch can be obtained without any change in the liquid crystal temperature range in the preparation of the composition.

Further, the compound of the present invention can be contained in an optical film. For example, by compounding the compound of the present invention with a polymerizable liquid crystal substance or a polymer liquid crystal,
Optical film in which the orientation direction of molecules is twisted, for example, ST
An optical compensation film for an N element can be formed. Further, when the structure is expressed in the smectic C phase, a periodic defect is generated, and the defect can be used as a diffraction grating. Further, the compound of the present invention can be used as a selective reflection film (color filter) by blending it with a polymerizable liquid crystal substance or polymer liquid crystal. Furthermore, the compounds of the present invention can be used for recording media.
For example, when a compound that isomerizes by azo or styrene light is added to the composition containing the compound of the present invention, the helical pitch of the liquid crystal is changed by irradiation with light (ultraviolet light). Application to patterning of a type recording medium or a color filter is also possible.

[0024]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited to these Examples. Example 1 [optically active 3,5-difluoro-1- [4- (trans-4-propylcyclohexyl) cyclohexene-1-]
[Production of benzene] In a three-necked flask sufficiently purged with nitrogen, 2.3 g of cut magnesium was put, and 1-g
12 g of bromo-3,5-difluorobenzene was added to THF2
The solution dissolved in 5 ml was added with stirring to obtain 3,5-difluorophenylmagnesium bromide. To this, a solution of 9.2 g of 4- (trans-4-propylcyclohexyl) cyclohexanone dissolved in 20 ml of THF was added over 30 minutes while maintaining the temperature at 10 ° C. After further reacting at 40 ° C. for 2 hours, the temperature was returned to room temperature, and 300 ml of 3N hydrochloric acid was added while cooling with ice. After extracting the reaction solution with benzene, benzene was distilled off, the remaining oily substance was dissolved in 200 ml of toluene, 1 g of p-toluenesulfonic acid was added, and the mixture was refluxed for 6 hours on a mantle heater to react. After the completion of the reaction, the toluene layer was
After being neutralized by washing with OH, toluene was distilled off. The remaining oil was subjected to column chromatography with activated alumina using n-hexane as a solvent. When the optical rotation of the concentrated solution was measured with a polarimeter, it was 0 degree and was optically inactive. Then, recrystallization from hexane yielded fine crystals. This crystal exhibits only a nematic phase without a twisted structure, and its phase transition temperature is 62 ° C. at the CN point (crystal-nematic point) and 86 at the NI point (nematic-clearing point).
° C. Although rhombic crystals were also obtained, they had similar transition temperatures. A hexane solution of these crystals (concentration: 15% by weight) was placed in a glass beaker and allowed to stand for 6 days while maintaining the ambient temperature at 20 ° C., and recrystallized, whereby a radial aggregate of single crystal pieces was obtained. When this one piece was taken and its phase transition was measured, it showed a cholesteric phase (Ch) and was found to be an optically active substance. This phase transition temperature is C-
Ch point (crystal-cholesteric point) is 70 ° C, Ch-I
The point (cholesteric-clearing point) is 87 ° C. and the melting point is different from the racemic form. This Ch phase exhibited selective reflection, and the selective reflection wavelength was 470 nm. When the helical pitch is calculated based on the selective reflection wavelength, 300 nm is obtained.
Met.

Example 2 An optical system was prepared in the same manner as in Example 1 except that 4- (trans-4-propylcyclohexyl) cyclohexanone in Example 1 was replaced with 4- (trans-4-pentylcyclohexyl) cyclohexanone. Active 3,5-difluoro 1-
[4- (Trans-4-pentylcyclohexyl) cyclohexen-1-yl] benzene was produced. This phase transition temperature is 58.5 to 59.8 ° C. at the C-Ch point and Ch-I
The point was 93.1 ° C. This material selectively reflected light having a wavelength of 470 nm, and its helical pitch was 300 μm.

Example 3 Optical activity was obtained in the same manner as in Example 1 except that 4- (trans-4-propylcyclohexyl) cyclohexanone was replaced with 4- (trans-4-butylcyclohexyl) cyclohexanone. 3,5-difluoro 1- [4
-(Trans-4-butylcyclohexyl) cyclohexen-1-yl] benzene can be produced.

Example 4 [Preparation of Guest Host Device] A polyimide alignment film LQ-1800 manufactured by Hitachi Chemical DuPont was formed on a glass substrate with ITO, and the alignment film surfaces were opposed to each other without rubbing. And bonded with a two-part epoxy resin adhesive mixed with spacer beads with a diameter of 8 μm,
A driving cell was formed. When the thickness of this cell was measured by an optical interference method, it was 7.6 μm. A liquid crystal composition having the following composition was injected into this. ZLI-2806 (liquid crystal composition manufactured by Merck) 95.0% by weight NKX-1366 (dichroic dye manufactured by Nippon Kogaku Dyeing Co., Ltd.) 2.0% by weight Compound of Example 1 3.0% by weight At 25 ° C, A 1 kHz rectangular wave voltage was applied to the device, and the transmittance of white light (non-polarized light, natural light) was measured. The results are shown in FIG. In FIG. 1, ○ indicates the transmittance in the process of increasing the applied voltage, and △ indicates the transmittance in the process of decreasing the voltage. As is clear from FIG. 1, the liquid crystal composition has a high transmittance and a high contrast, which are features of the guest-host device, and has no dependency on the voltage history of the transmittance. Therefore, it can be seen that the liquid crystal composition gives excellent device characteristics.

Example 5 [Preparation of phase change type element] A polyimide alignment film LX-1400 manufactured by Hitachi Chemical DuPont was formed on a glass substrate with ITO, and then rubbed so that the alignment film surfaces faced each other. 2 mixed with spacer beads having a diameter of 6.5 μm
A drive cell was formed by bonding with a liquid epoxy resin adhesive. When the thickness of this cell was measured by an optical interference method, it was 6.0 μm. To this, a composition in which the enantiomers of the compound of Example 1 were mixed at a weight ratio of 43:57 was injected. (An enantiomer of the compound of Example 1 was obtained by reheating the filtrate in which the compound of Example 1 was precipitated and then allowed to cool and stand.) The helical pitch of this composition was determined using the canoe edge method. It was confirmed to be 4 μm. At 80 ° C,
A 1 kHz rectangular wave was applied to this device, and the change in orientation with respect to the voltage was observed using a polarizing microscope. Planar orientation from 0 V to 4.5 V, and 4.5 V to 11.0 V
In the focal conic fan structure in the range of 11.0 V or higher, and changed to homeotropic alignment. When this change was observed directly by visual observation, it was found that the film was transparent in the planar orientation and the homeotropic orientation, and showed a white turbid state due to light scattering at a voltage that gave the focal conic fan structure. Turned out to be possible.

Example 6 [Preparation of Selective Reflective Element] A polyimide alignment film LX-1400 manufactured by Hitachi Chemical DuPont was formed on a glass substrate with ITO, and then rubbed so that the alignment film surfaces faced each other. The two-component epoxy resin adhesive mixed with spacer beads having a diameter of 4.0 μm was bonded together to form a driving cell. When the thickness of this cell was measured by an optical interference method, it was 3.5 μm. The compound of Example 1 was injected into this. At 80 ° C., this device exhibits a blue selective reflection. A 1 kHz rectangular wave was applied to the device, and the change in orientation with respect to the voltage was observed using a polarizing microscope.
From 9 V to 9 V, to a focal conic fan structure in the range of 9 V to 47 V, and to a homeotropic alignment at 47 V or more. When this change was observed directly by visual observation, it showed a selective reflection of blue in the planar orientation, a cloudy state colored by a voltage giving the focal conic fan structure, and a transparent state in the homeotropic orientation. It has been found that optical switching suitable as a liquid crystal operation mode is possible.

Embodiment 7 [Prevention of Reverse Twist Domain Generation in TN Device] A polyimide alignment film LX-1400 manufactured by Hitachi Chemical DuPont is formed on a glass substrate with ITO, and then rubbed to a rubbing angle of 90 degrees. The substrates were opposed to each other as described above, and bonded with a two-liquid epoxy resin adhesive mixed with spacer beads having a diameter of 6 μm to form a driving cell. When the thickness of this cell was measured by an optical interference method, it was 5.4 μm. The following composition was injected into this. This was inserted between two polarizing plates whose absorption axes were orthogonal to each other, and visually observed, it was confirmed that no reverse twist domain was generated. ZLI-1132 (liquid crystal composition manufactured by Merck) 95.0% by weight Compound of Example 1 0.5% by weight

Example 8 [Manufacture of STN element] A polyimide alignment film SE-150 manufactured by Nissan Chemical Co., Ltd. was formed on a glass substrate with ITO, and then rubbed, and the rubbing angle was 40 degrees (the twist angle of the liquid crystal was 220. The substrates were opposed to each other so as to obtain a driving cell, and bonded with a two-liquid epoxy resin adhesive mixed with spacer beads having a diameter of 7.6 μm to form a driving cell. When the thickness of this cell was measured by an optical interference method, it was 7.0 μm. The following composition was injected into this.
Insert this between two polarizing plates whose absorption axes are orthogonal,
At 25 ° C., a 1 kHz rectangular wave was applied, and the transmittance was measured with respect to the voltage. The results are shown in FIG. As is clear from FIG. 2, it was found that the composition provided excellent device characteristics showing a steep threshold which is a feature of the STN device. ZLI-5000-000 (liquid crystal composition manufactured by Merck) 97.5% by weight Compound of Example 1 2.5% by weight

Example 9 [Formation of Optical Compensation Film for STN Element] TA having a thickness of 80 μm
A PVA film having a saponification degree of 99.5% was formed on C by a bar coating method, and heated at 110 ° C. for 3 minutes. This was subjected to a rubbing treatment, and a coating solution prepared according to the following formulation was heated and coated thereon with a bar coater, and dried in an oven at 120 ° C. for 3 minutes.

[0033]

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This was subjected to UV irradiation at 100 ° C. using a high-pressure mercury lamp to polymerize and cure the film. When the thickness of this film was measured, it was 5.0 μm. It was found from the polarization transmission spectrum profile of this film that the orientation of the liquid crystal molecules was twisted 240 degrees in the thickness direction of the film at 240 degrees. This film was superposed so that the molecular direction of the portion fitted to the reverse twisted STN cell was perpendicular to the film, and the film was inserted between two polarizing plates whose absorption axes were perpendicular to each other. As shown, it was confirmed that this film functions as an optical compensation film for STN.

Example 10 [Preparation of selective opposite film (color filter)] A polyimide alignment film LX-1 manufactured by Hitachi Chemical DuPont on a glass substrate.
400 was formed, and a rubbing treatment was performed. A coating solution prepared according to the following formulation was applied thereon by a spin coater, and the alignment was matured in an oven at 120 ° C. for 3 minutes.

[0036]

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This was subjected to UV irradiation at 120 ° C. using a high-pressure mercury lamp to polymerize and cure the film. When the thickness of this film was measured, it was 3.0 μm. When the transmission spectrum of this film was measured, it was confirmed that the film exhibited selective reflection at 540 nm.

[0038]

The optically active liquid crystalline compound of the present invention exhibits a cholesteric liquid crystal phase by itself and has a high voltage holding ratio. And the optically active liquid crystalline compound is
The racemate can be easily obtained by optical resolution by a relatively simple means of recrystallization. Further, the compound can be applied to a liquid crystal composition, an optical film, and a recording medium.

[Brief description of the drawings]

FIG. 1 is a graph showing light transmittance of a guest host device of Example 4 during a voltage increasing process and a voltage decreasing process.

FIG. 2 is a graph showing a relationship between an applied voltage and a light transmittance in the STN element of Example 8.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/13 500 G02F 1/13 500 // C07M 7:00 C07M 7:00 F term (Reference) 4H006 AA01 AA02 AA03 AB64 AB92 AD15 AD17 BB16 BB17 BC51 EA41 4H027 BA02 BB02 BB03 BB04 BC05 BD02 BD03 BD04 BD05 BD07 BD24 DP05

Claims (5)

[Claims] 1. An optically active 3,5-difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene represented by the following general formula (I). Embedded image In the formula, R represents a linear alkyl group, alkenyl group or alkynyl group having 1 to 10 carbon atoms. 2. A liquid crystal composition containing an optically active 3,5-difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene represented by the above general formula (I). . 3. An optical film containing the optically active 3,5-difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene represented by the general formula (I). 4. A recording medium containing optically active 3,5-difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene represented by the general formula (I). 5. A step of recrystallizing the optically inactive 3,5-difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene represented by the general formula (I). A method for producing optically active 3,5-difluoro-1- [4- (trans-4-substituted cyclohexyl) cyclohexen-1-yl] benzene represented by the above general formula (I).